Impedance measuring device

Abstract

To use a signal injection unit made to low breakdown voltage specification so as to sufficiently reduce manufacturing costs.SOLUTION: The present invention comprises: a signal injection unit 3 for injecting an AC signal S1 to an injection target line to which a battery Bat is connected in series; a contactless current sensor 5 for detecting the current value of the AC signal S1 flowing in an injection target line L without contacting the injection target line L and outputting a detection signal S3; a voltage detection unit 6 for contacting both ends of the battery Bat to detect the voltage value of an AC voltage generated at the both ends and outputting a both ends voltage S4; and a processing unit 7 for measuring an internal impedance Zb of the battery Bat on the basis of the detection signal S3 and the both ends voltage signal S4. The signal injection unit 3 is constituted so as to be capable of contactlessly injecting the AC signal S1 to the injection target line L.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an impedance measuring device that measures the impedance of a measurement target connected in series to an injection target line in a state where a measurement AC signal is injected into the injection target line formed of a conductor by a signal injection unit.

Background Art

[0002] As this type of impedance measuring device, an internal impedance measuring device for a battery (hereinafter also referred to as a "measuring device") disclosed in the following patent document is known. This measuring device includes an AC power supply unit, an AC voltage detection unit, an AC current detection unit, and an arithmetic control unit, and is configured to be able to measure the internal impedance of a secondary battery in a state where a DC current is supplied to a load connected via a pair of power lines.

[0003] In this measuring device, an AC current supply unit functions as a signal injection unit and supplies a measurement AC current to the secondary battery. At this time, the AC voltage detection unit detects the AC voltage generated between the terminals of the secondary battery when the AC current is supplied, and the AC current detection unit detects the AC current flowing through the secondary battery when the AC current is supplied. Next, the arithmetic control unit calculates the internal impedance of the secondary battery based on the AC voltage detected by the AC voltage detection unit and the AC current detected by the AC current detection unit. Therefore, in this measuring device, it is possible to measure the impedance of the secondary battery as a measurement target connected in series to a pair of power lines in a state where a measurement AC signal is injected into the pair of power lines formed of a conductor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the above-described measuring device has the following problems. Specifically, in this measuring device, when measuring impedance, the AC power supply unit (signal injection unit) needs to be directly connected to both ends of the secondary battery and supply an AC current to the secondary battery through both ends. In this case, for example, the voltage at both ends of a secondary battery used in a fuel cell vehicle (FCV) is as high as about DC650V. Therefore, as internal components of the AC power supply unit directly connected to both ends of this secondary battery, expensive components having a withstand voltage equal to or higher than the output voltage of the secondary battery must be adopted. Therefore, the AC power supply unit must be configured with a high withstand voltage specification, and the manufacturing cost of the entire measuring device becomes extremely high, and there is a demand to improve this situation.

[0006] The present invention has been made in view of such problems, and even when a high voltage exists in an injection target line to which measurement objects are connected in series and an AC signal for measurement is injected, by using a signal injection unit with a low withstand voltage specification, it is possible to sufficiently reduce the manufacturing cost of the entire impedance measuring device and reliably measure the impedance of the measurement object. The main object is to provide an impedance measuring device.

Means for Solving the Problems

[0007] To achieve the above object, an impedance measuring device according to the present invention includes a signal injection unit that generates an AC signal for measurement and injects the AC signal into an injection target line to which measurement objects are connected in series, and a non-contact type current detection unit that non-contact detects a current value of the AC signal flowing through the injection target line and outputs a current detection signal. The voltage generated at both ends of the measurement object ru jiaoA voltage detection unit that detects the voltage value of an alternating current voltage by contacting both ends thereof and outputs a voltage detection signal, and a processing unit that inputs the current detection signal and the voltage detection signal and measures the impedance of the measurement target based on the current detection signal and the voltage detection signal. In the impedance measurement device, the signal injection unit is configured to be able to inject the alternating current signal into the injection target line in a non-contact manner.

[0008] In this impedance measurement device, the signal injection unit injects an alternating current signal into the injection target line in a non-contact manner, the non-contact type current detection unit detects the current value of the alternating current signal flowing through the injection target line in a non-contact manner with respect to the injection target line and outputs a current detection signal, the voltage detection unit detects the voltage value of the alternating current signal generated at both ends of the measurement target by contacting both ends thereof and outputs a voltage detection signal, and the processing unit inputs the current detection signal and the voltage detection signal and measures the impedance of the measurement target based on the current detection signal and the voltage detection signal.

[0009] Therefore, according to this impedance measurement device, even when there is a high voltage in the injection target line to which the measurement target is connected in series and the alternating current signal for measurement is injected, since the signal injection unit injects the alternating current signal into the injection target line in a non-contact manner, as a component constituting the signal injection unit, a component with a low withstand voltage specification can be used. As a result, the manufacturing cost of the signal injection unit can be reduced, and thus the manufacturing cost of the entire impedance measurement device can be sufficiently reduced, and the impedance of the measurement target can be reliably measured.

[0010] Further, in the impedance measurement device according to the present invention, the voltage detection unit includes an insulation circuit that outputs the detected voltage detection signal to the processing unit in a state of being insulated from the measurement target.

[0011] In this impedance measuring device, a non-contact current sensor non-contact detects the current of the alternating current flowing through the injection target line and outputs a current detection signal to the processing unit, and the voltage detection unit outputs the both-end voltage signal detected by contacting both ends of the measurement target to the processing unit in a state of being insulated from the measurement target. Thus, even if a very high voltage is generated in the measurement target, and even if noise such as switching noise exists around the load or the impedance measuring device, it is possible to accurately detect a minute alternating voltage generated in the measurement target due to the flow of a current based on the injection of an alternating signal into the measurement target. Therefore, according to this impedance measuring device, the impedance of the measurement target can be accurately measured. Further, according to this impedance measuring device, by using a non-contact current sensor, it is possible to measure the impedance of the measurement target non-contact without cutting the injection target line.

[0012] Further, in the impedance measuring device according to the present invention, the processing unit includes a first quadrature detection circuit that inputs the alternating signal and quadrature-detects the current detection signal to generate an in-phase component and a quadrature component of the alternating current, a second quadrature detection circuit that inputs the alternating signal and quadrature-detects the voltage detection signal to generate an in-phase component and a quadrature component of the alternating voltage, and an arithmetic circuit that calculates the impedance of the measurement target based on the in-phase component and the quadrature component of the alternating current output from the first quadrature detection circuit and the in-phase component and the quadrature component of the alternating voltage output from the second quadrature detection circuit.

[0013] According to this impedance measuring device, the arithmetic circuit of the processing unit calculates the impedance of the measurement target based on the in-phase component and the quadrature component of the alternating current output from the first quadrature detection circuit and the in-phase component and the quadrature component of the alternating voltage output from the second quadrature detection circuit. Thus, even when the signal level of the alternating signal injected into the injection target line is small, it is possible to increase the ratio (S / N) of the signal level (S) to the noise level (N) and accurately measure the impedance.

[0014] In addition, in the impedance measurement device according to the present invention, the signal injection unit includes a primary winding component that constitutes a primary winding magnetically coupled to the injection target line as a secondary winding, and applies the AC signal to the primary winding component to inject the AC signal into the injection target line.

[0015] In addition, in the impedance measurement device according to the present invention, the primary winding component includes an insulated wire wound around an annular first magnetic core through which the injection target line is inserted.

[0016] According to these impedance measurement devices, the primary winding component can be simply configured, and the AC signal can be surely injected into the injection target line.

[0017] In addition, in the impedance measurement device according to the present invention, the first magnetic core is provided with a gap. According to this impedance measurement device, by providing a gap in the magnetic core, magnetic saturation of the magnetic core can be avoided.

[0018] In addition, in the impedance measurement device according to the present invention, the first magnetic core is composed of a plurality of C-shaped unit magnetic cores, and the plurality of unit magnetic cores are stacked such that the separation distances of two adjacent gaps along the outer periphery of the first magnetic core are equal in a top view of the stacked state.

[0019] According to this impedance measurement device, even if the injection target line inserted into the magnetic core is located near the gap, regardless of its position, the AC signal can be stably injected into the injection target line without reducing the injection of the AC signal into the injection target line.

[0020] In addition, in the impedance measurement device according to the present invention, the primary winding component is composed of the insulated coated wires wound around the first magnetic core and is composed of Na windings from the first winding to the Na-th winding (Na is an integer of 2 or more) connected in series as a whole, and the primary winding component includes Na switches from the first parallel switch to the Na-th parallel switch respectively connected in parallel to the first winding to the Na-th winding, and the processing unit controls on / off of the Na parallel switches to change the number of turns of the primary winding component as a whole.

[0021] According to this impedance measurement device, by changing the number of turns of the primary winding component as a whole, regardless of the magnitude of the load impedance seen from the signal injection winding when the load is connected to the measurement target and in a closed loop state, an AC signal can be accurately injected into the injection target line.

[0022] In addition, in the impedance measurement device according to the present invention, the first winding to the Na-th winding are each wound so that their number of turns is different from each other. According to this impedance measurement device, it is possible to increase or decrease the number of turns more significantly compared to a primary winding component configured with the same number of turns.

[0023] In addition, in the impedance measurement device according to the present invention, the first winding to the Na-th winding are each 2 Ma (Ma is an integer of 0 to (Na - 1), and there are Na integers) multiplied by an integer La of 1 or more. According to this impedance measurement device, the number of turns of the primary winding component as a whole can be finely controlled.

[0024] In addition, in the impedance measurement device according to the present invention, the first winding to the Na-th winding are formed such that the wire diameter of the core wire in the insulated coated wire of the winding with a larger number of turns is thinner than the wire diameter of the core wire in the insulated coated wire of the winding with a smaller number of turns. According to this impedance measurement device, as a result of being able to use a thin insulated coated wire (or enameled wire) for the winding with a larger number of turns, the productivity of the signal injection winding can be sufficiently improved.

[0025] In addition, in the impedance measurement device according to the present invention, the signal injection unit includes a capacitor circuit that forms an LC resonance circuit having a resonance point at the frequency of the AC signal or a frequency near the frequency together with the primary winding. According to this impedance measurement device, since the signal injection unit includes a capacitor circuit that forms an LC resonance circuit having a resonance point at the frequency of the AC signal or a frequency near the frequency together with the primary winding, as a result, the AC signal easily flows through the primary winding, and thus the loss of the AC signal in the LC resonance circuit can be sufficiently reduced.

[0026] In addition, in the impedance measurement device according to the present invention, the signal injection unit includes a damping resistor that reduces the Q value of the LC resonance circuit. According to this impedance measurement device, even if the frequency of the AC signal generated by the signal injection unit is somewhat different from the resonance frequency of the LC resonance circuit, the loss of the AC signal in the LC resonance circuit can be sufficiently reduced.

[0027] In addition, in the impedance measurement device according to the present invention, the signal injection unit includes an amplifier circuit that amplifies the AC signal, and the LC resonance circuit is arranged as a load circuit of the amplifier circuit. According to this impedance measurement device, a sine-wave AC signal can be linearly amplified with respect to the amplifier circuit.

[0028] In addition, in the impedance measurement device according to the present invention, one end of the LC resonance circuit is connected to a high potential and is configured by an LC parallel resonance circuit, the amplifier circuit is configured by an N-channel MOSFET, the other end side of the LC resonance circuit is connected to the drain terminal, the source terminal is connected to a low potential, and a pulse signal as the AC signal is input to the gate terminal to perform class-D amplification of the AC signal. According to this impedance measurement device, the amplifier circuit can be simply configured.

[0029] Further, the impedance measuring device according to the present invention is configured such that the voltage of the high potential is variable. According to this impedance measuring device, as a result of the change in the drain voltage of the FET, the voltage (which is also power) of the AC signal output from the FET can be freely changed.

[0030] Further, in the impedance measuring device according to the present invention, one end of the LC resonance circuit is connected to the reference potential and is configured as an LC series resonance circuit, the amplifier circuit is configured as a push-pull circuit by an N-channel MOSFET and a P-channel MOSFET, the drain terminal of the N-channel MOSFET is connected to a potential higher than the reference potential, the drain terminal of the P-channel MOSFET is connected to a potential lower than the reference potential, the other end side of the LC series resonance circuit is connected to the source terminals of the N-channel MOSFET and the P-channel MOSFET, and a positive pulse signal as the AC signal is input to the gate terminal of the N-channel MOSFET and a negative pulse signal as the AC signal is input to the gate terminal of the P-channel MOSFET to perform class-D amplification of the AC signal. According to this impedance measuring device, the AC signal can be surely class-D amplified by the amplifier circuit configured as a push-pull circuit.

[0031] Further, the impedance measuring device according to the present invention is configured such that the voltage of the high potential and the voltage of the low potential are each variable. According to this impedance measuring device, as a result of the change in the drain voltages of the two FETs, the voltages (which are also power) of the AC signals output from the two FETs can be freely changed.

[0032] Further, the impedance measuring device according to the present invention includes either an LPF or a BPF connected in series to the LC resonance circuit to allow the passage of the AC signal. According to this impedance measuring device, the sine-wave AC signal can be surely amplified linearly with respect to the amplifier circuit.

[0033] In addition, in the impedance measurement device according to the present invention, the capacitor circuit includes Nb capacitors from a first capacitor to an Nb-th capacitor (Nb is an integer of 2 or more) connected in parallel as a whole, and Nb switches from a first series switch to an Nb-th series switch each connected in series to the first capacitor to the Nb-th capacitor. The processing unit controls on / off of the Nb series switches according to the frequency of the AC signal to change the capacitance of the entire capacitor circuit. According to this impedance measurement device, the processing unit can finely control the resonance frequency of the LC resonance circuit by controlling on / off of the Nb switches according to the frequency of the AC signal and changing the capacitance of the capacitor circuit CS.

[0034] In addition, in the impedance measurement device according to the present invention, the capacitances of the first capacitor to the Nb-th capacitor are different from each other. According to this impedance measurement device, it is possible to increase or decrease the capacitance more significantly compared to a capacitor circuit composed of capacitors having the same capacitance.

[0035] In addition, in the impedance measurement device according to the present invention, the first capacitor to the Nb-th capacitor each have a capacitance obtained by multiplying a specific capacitance by 2 Mb (Mb is an integer of Nb from 0 to (Nb - 1)). According to this impedance measurement device, since the capacitance of the entire capacitor circuit can be changed, the resonance frequency of the LC resonance circuit can be finely controlled. In this case, by increasing the number of capacitors in the capacitor circuit, the resonance frequency can be linearly changed.

[0036] maFurther, the impedance measuring device according to the present invention includes a plurality of the primary winding components corresponding to frequency band groups obtained by grouping the frequency bands of the generated AC signals, respectively. When injecting the AC signal having a frequency belonging to one of the frequency band groups, the AC signal is applied to both ends of the primary winding component corresponding to the one frequency band group. The frequency band is grouped into two frequency band groups, and the first magnetic core in the primary winding component corresponding to the frequency band group on the low-frequency band side of the two frequency band groups is composed of a metal magnetic core, and the first magnetic core in the primary winding component corresponding to the frequency band group on the high-frequency band side of the two frequency band groups is composed of a ferrite magnetic core.

[0037] ma Further, the impedance measuring device according to the present invention includes a plurality of the primary winding components corresponding to frequency band groups obtained by grouping the frequency bands of the generated AC signals, respectively. When injecting the AC signal having a frequency belonging to one of the frequency band groups, the AC signal is applied to both ends of the primary winding component corresponding to the one frequency band group. The frequency band is grouped into three frequency band groups, and the first magnetic core in the primary winding component corresponding to the frequency band group on the low-frequency band side of the three frequency band groups is composed of a metal magnetic core, the first magnetic core in the primary winding component corresponding to the frequency band group on the middle-frequency band side of the three frequency band groups is composed of a ferrite magnetic core, and the primary winding component corresponding to the frequency band group on the high-frequency band side of the three frequency band groups is composed of an air-core coil.

[0038] koAccording to these impedance measuring devices, when injecting an AC signal into the injection target line by a transformer method, a magnetic core or an air-core coil made of a material with the most suitable coupling to the injection target line according to the frequency of the AC signal can be used. Therefore, the AC signal can be injected into the injection target line sufficiently efficiently over a wide frequency band.

[0039] ma Further, in the impedance measuring device according to the present invention, the signal injection unit is configured to be able to change the frequency of the AC signal, and when changing the frequency of the AC signal from one of the two frequency band groups adjacent to each other to the other at the boundary of the two frequency band groups whose frequency bands of the AC signal are adjacent to each other, the AC signal is applied to the two primary winding component parts corresponding to the two adjacent frequency band groups.

[0040] ko According to the impedance measuring device, at the boundary, two types of primary winding component parts made of materials with suitable coupling to the injection target line according to the frequency of the AC signal are used. Therefore, the AC signal can be injected into the injection target line sufficiently efficiently. Further, according to this impedance measuring device, when changing the frequency of the AC signal from one frequency band group to the other at the boundary, the fluctuation of the signal level of the AC signal caused by the switching of the primary winding component part to which the AC signal is applied can be alleviated.

[0041] ma Further, the impedance measuring device according to the present invention includes a signal detection unit that detects the current value of the AC signal flowing through the injection target line, and the processing unit controls the signal level of the AC signal output from the signal injection unit so that the current value of the AC signal detected by the signal detection unit is included within a target current value range.

[0042] maThe impedance measurement device according to the present invention includes a signal detection unit that detects a current value of the alternating current signal flowing through the injection target line, and the processing unit is the current value of the alternating current signal detected by the signal detection unit ga me controls the on / off of the first parallel switch to the Na-th parallel switch so as to be included within the standard current value range.

[0043] ma The impedance measurement device according to the present invention includes a signal detection unit that detects a current value of the alternating current signal flowing through the injection target line, and the processing unit determines the load impedance of the injection target line based on the current value of the alternating current signal injected by the signal injection unit into the injection target line and the current value of the alternating current signal detected by the signal detection unit, and controls the on / off of the first parallel switch to the Na-th parallel switch, so that when the determined load impedance is small, the number of turns of the entire primary winding component is increased, and when the determined load impedance is large, the number of turns of the entire primary winding component is decreased.

[0044] ko According to these impedance measurement devices, the ratio (S / N) of the signal level (S) to the noise level (N) of the current detection signal and the voltage detection signal can be increased. As a result, in the impedance calculation process (measurement process) performed by the processing unit, the impedance can be measured accurately.

[0045] ma The impedance measurement device according to the present invention is configured such that the signal detection unit is formed separately from the signal injection unit and includes a secondary winding component that forms a primary winding magnetically coupled to the injection target line as a secondary winding.

[0046] koAccording to the impedance measuring device, since the non-contact current detection unit as the signal detection unit is formed separately from the signal injection unit and includes a secondary winding component, it is possible to avoid leakage of the leakage magnetic flux corresponding to the AC signal injected by the signal injection winding of the signal injection unit into the secondary winding component as noise, so that the impedance can be measured accurately.

[0047] ma In addition, in the impedance measuring device according to the present invention, the signal detection unit functions as the current detection unit. According to this impedance measuring device, by the non-contact current detection unit combining the configuration of the current detection unit and the configuration of the signal detection unit, the impedance measuring device can be miniaturized and the manufacturing cost can be sufficiently reduced.

[0048] Further, in the impedance measuring device according to the present invention, the primary winding component is composed of an air-core coil. According to this impedance measuring device, although the configuration is simple, an AC signal in a high-frequency band can be surely injected into the injection target line.

[0049] Moreover, the impedance measuring device according to the present invention includes a plurality of the signal injection units, and the plurality of signal injection units simultaneously apply the AC signals having the same frequency and the same phase to the plurality of primary winding components of the same specification. According to this impedance measuring device, compared with using one primary winding component, an AC signal with a sufficiently large current value can be injected into the injection target line.

[0050] In addition, the impedance measuring device according to the present invention includes a plurality of voltage detection units, and the plurality of voltage detection units are generated at both ends of each of the plurality of measurement targets connected in series to the injection target line. ru jiaoThe voltage value of the alternating current voltage is detected by contacting each of the two ends, and the voltage detection signals are respectively output to the processing unit. The processing unit measures the impedance of each of the plurality of measurement objects based on the current detection signal and the plurality of voltage detection signals respectively output from the plurality of voltage detection units. According to this impedance measurement device, the impedances of a plurality of measurement objects can be measured simultaneously.

[0051] In addition, the impedance measurement device according to the present invention includes a capacitor connected in parallel to both ends of the non-measurement object in the measurement system in which the measurement object and the non-measurement object are connected by the injection target line to form a circular closed loop. According to this impedance measurement device, even if the impedance of the non-measurement object is large, the current value at the time of injecting an alternating current signal into the injection target line by the signal injection unit can be increased.

[0052] In addition, the impedance measurement device according to the present invention is such that the signal injection unit includes a class D amplifier section as a final stage, and injects the alternating current signal amplified by the class D amplifier section into the injection target line. According to this impedance measurement device, the signal injection unit can maintain the output level of the alternating current signal at a constant level controlled against load fluctuations.

[0053] In addition, the impedance measurement device according to the present invention is such that the signal injection unit sweeps the frequency of the alternating current signal. According to this impedance measurement device, since it can be configured as an FRA that supplies an alternating current signal that is a sine wave signal to the measurement object and measures its frequency response, high-precision impedance measurement can be performed.

[0054] In addition, in the impedance measuring device according to the present invention, the metal magnetic core is any one of a permalloy core, a sendust core, an amorphous core, a dust core, pure iron, silicon steel sheet, permendur, nickel, cobalt, Fe-Si-Al, and electromagnetic stainless steel, and the ferrite magnetic core is any one of an Mn-Zn ferrite and an Ni-Zn ferrite. According to this impedance measuring device, by using any one of the above types as the metal magnetic core, a magnetic core that is difficult to be magnetically saturated with respect to a direct current can be configured, and by using any one of the above types as the ferrite magnetic core, the generation of eddy currents in the magnetic core can be avoided.

Effect of the Invention

[0055] According to the impedance measuring device of the present invention, even when a high voltage exists in the injection target line to which the measurement object is connected in series and the AC signal for measurement is injected, since the signal injection unit injects the AC signal in a non-contact manner with respect to the core wire of the injection target line, as a result, components with a low withstand voltage specification can be used as the components constituting the signal injection unit, and thus the manufacturing cost of the signal injection unit can be reduced, and furthermore, the manufacturing cost of the entire impedance measuring device can be sufficiently reduced, and the impedance of the measurement object can be reliably measured.

Brief Description of the Drawings

[0056]

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Embodiments for Carrying Out the Invention

[0057] Hereinafter, embodiments of the impedance measurement device will be described with reference to the accompanying drawings.

[0058] The impedance measurement device 1 shown in FIG. 1 is an example of an "impedance measurement device". For example, when a load Load (non-measurement target) is connected to the measurement target to form a closed loop state, the impedance (in this example, the internal impedance Zb) of the battery (battery) Bat as the measurement target can be measured. Further, the impedance measurement device 1 is configured as a FRA (Frequency Response Analyzer) that can supply an AC signal S1, which will be described later, as a sine wave signal to the battery Bat and measure its frequency response, enabling highly accurate impedance measurement.

[0059] For example, in a fuel cell vehicle, a load Load that consumes a large direct current such as a motor and a battery Bat (illustrated as one battery as a whole in the figure) configured by connecting a plurality of battery cells in series are connected by a power line (hereinafter, also referred to as "injection target line L") formed of a conductor such as an insulated cable in which a core wire, which is a conductor, is insulated, an enameled wire, and a non-insulated wire. A large direct current flows from the battery Bat to the load Load through this injection target line L. In order to measure the internal impedance Zb of the battery Bat in such a connection state, it is necessary to supply an AC signal S1 for impedance measurement (for example, 1 Hz to 10 MHz) to the battery Bat. At this time, in this impedance measurement device 1, the AC signal S1 can be injected into the injection target line L through which a large direct current flows from the battery Bat to the load Load by using an injection extraction device 10 described later.

[0060] Specifically, the impedance measurement device 1 includes a magnetic core 2, a signal injection unit 3, a magnetic flux cancellation unit 4, a non-contact current sensor 5, a voltage detection unit 6, a processing unit 7, and an output unit 8. In this case, the signal injection device 10 is constituted by the magnetic core 2, the signal injection unit 3, and the magnetic flux cancellation unit 4.

[0061] The magnetic core 2 is a component that constitutes the signal injection section 3 and the magnetic flux cancellation section 4. For example, using materials such as ferrite, permalloy, permendur, silicon steel sheet, and pure iron, it is formed in an annular shape such as circular, elliptical, rectangular, and polygonal so that the injection target line L through which the direct current Ib flows can be inserted. Further, the magnetic core 2 has a magnetic flux cancellation winding W1 as a first winding for supplying a negative feedback direct current (hereinafter also referred to as "cancellation current Ic") as a cancellation current for magnetic flux cancellation, and a signal injection winding W2 as a second winding for injecting the alternating signal S1 wound thereon, and a Hall element 41 is disposed in the gap G. In this case, by providing the gap G, it is difficult for the magnetic core 2 to be magnetically saturated. Note that, for the magnetic core 2, a dividable clamp type configuration can also be adopted. Further, a signal is injected into one end of the magnetic flux cancellation winding W1 and the signal injection winding W2, and the other end is connected to a reference potential (floating ground) described later.

[0062] The signal injection unit 3 is configured to generate an AC signal S1 for measurement and inject it non - contactingly into the injection target line L (with respect to the core wire (conductive wire) of the injection target line L). Specifically, the signal injection unit 3 includes a signal generation circuit 31 configured to generate the AC signal S1 and amplify the AC signal S1 in a class - D amplifier circuit arranged at the output stage and output it, the magnetic core 2 described above, and the signal injection winding W2 described above. In this case, since the signal injection unit 3 injects the AC signal S1 non - contactingly into the core wire of the injection target line L, as each component, components with a very low withstand voltage specification are used as compared with the output voltage of the battery Bat. In this signal injection unit 3, the signal generation circuit 31 is controlled by the control signal Sc1 output from the processing unit 7 for the signal level and frequency of the AC signal S1 to be injected into the injection target line L, sweeps the frequency (for example, 1 Hz to 10 MHz), outputs the generated AC signal S1 to the processing unit 7, amplifies it in class - D, and supplies it to the signal injection winding W2. In this case, the signal injection winding W2 is composed of an insulated coated wire (or enameled wire, etc.) wound around the magnetic core 2 (the first magnetic core) and functions as a primary winding component CP1 that constitutes a primary winding magnetically coupled to the injection target line L as a secondary winding. Therefore, by supplying the AC signal S1 to the signal injection winding W2 in a transformer manner (the signal injection winding W2 is a multi - turn primary winding and the injection target line L is a one - turn secondary winding) (that is, applying the AC signal S1 to both ends of the signal injection winding W2), an alternating current Iac based on the AC signal S1 flows through the signal injection winding W2, a magnetic flux Mc based on the AC signal S1 is generated in the magnetic core 2 in the direction shown in FIG. 1, and an injection current Ii, which is an AC signal with a current value corresponding to the magnitude of the magnetic flux Mc, is supplied (injected) to the injection target line L as a normal - mode signal. Note that the frequency sweep by the signal generation circuit 31 is not essential. When the sweep is not required, a configuration for generating an AC signal S1 with a fixed frequency can also be applied to the signal generation circuit 31.

[0063] When a direct current Ib flows through the injection target line L, the magnetic flux cancellation unit 4 generates, by the zero-flux method, a magnetic flux Md as a second magnetic flux in the direction opposite to the magnetic flux Mb, which is the first magnetic flux generated in the magnetic core 2 in the direction shown in FIG. 1, in the magnetic core 2 so as to be cancellable (offset). Specifically, the magnetic flux cancellation unit 4 includes a Hall element 41 as an example of a magnetic flux detection circuit disposed in the above-described gap G, a voltage driver 42, a low-pass filter 43 (hereinafter also referred to as "LPF43"), the above-described magnetic core 2, and a signal injection winding W2. Note that, for example, when the impedance of the load Load is large or when the output voltage of the battery Bat is low, the current value of the direct current Ib may become small or almost no direct current Ib may flow. When assuming the use of the impedance measurement device 1 in such a situation, since magnetic saturation of the magnetic core 2 does not occur, the function of the magnetic flux cancellation unit 4 may not be used, or the arrangement of the magnetic flux cancellation unit 4 itself may be omitted. The impedance measurement devices 1A to 1C having a configuration in which the arrangement of the magnetic flux cancellation unit 4 is omitted will be described later.

[0064] The Hall element 41 is an example of a "magnetic flux detection circuit" and is provided in the magnetic core 2 to output a voltage signal S2 corresponding to the magnetic flux generated in the magnetic core 2. In this case, the configuration may be such that a current signal is output as a detection signal from the Hall element 41, and a signal converted into a voltage signal by such a current signal is also included in the "voltage signal S2". Note that the "magnetic flux detection circuit" is not limited to a Hall element, and a fluxgate sensor, a magnetoresistive element (MR), or the like may be disposed in the magnetic core 2 to configure it. Further, as the magnetoresistive element, a GMR element (Giant Magneto Resistive), a semiconductor magnetoresistive element (SMR), an anisotropic magnetoresistive element (AMR) using a ferromagnetic thin film material, a giant magnetoresistive element (GMR), and a tunnel magnetoresistive element (TMR) can be used.

[0065] The voltage driver 42 is an example of an amplifier circuit that functions as a negative feedback amplifier circuit as a whole, amplifies the voltage signal S2, and outputs it to the LPF 43 with low impedance. The LPF 43 is an example of a filter circuit that blocks the output of the voltage signal S2 based on the AC signal S1 included in the voltage signal S2 amplified by the voltage driver 42, allows the voltage signal S2 based on the DC current Ib to pass through, supplies the cancellation current Ic to the magnetic flux cancellation winding W1 in a direction to cancel the magnetic flux Mb, and blocks the input of the voltage signal (the voltage signal generated in the cancellation winding based on the AC signal) generated in the magnetic flux cancellation winding W1 to the voltage driver 42 based on the magnetic flux Mc generated in the magnetic core 2 by the supply to the signal injection winding W2 of the AC signal S1. Specifically, as shown in FIG. 1, for example, the LPF 43 is composed of an L-type LC filter in which a capacitor C1 is connected between the input terminal Ti on the voltage driver 42 side and the reference potential, and an inductor L1 is connected between the input terminal Ti and the output terminal To on the magnetic flux cancellation winding W1 side. As shown in FIG. 2, it has a frequency characteristic in which its cut-off frequency is lower than the frequency of the AC signal S1 (when the frequency is swept, the lowest frequency of the AC signal S1), blocks the output of the voltage signal S2 based on the AC signal S1, and allows the voltage signal S2 based on the DC current Ib to pass through.

[0066] In this case, in order to allow only the voltage signal S2 based on the direct current Ib to pass through, it is preferable that the cut-off frequency is as close as possible to the frequency 0 Hz. Therefore, in this magnetic flux cancellation section 4, for example, a filter circuit is configured by an LPF43 including an inductor L1 formed of a reactor with a large inductance. For this reason, the cut-off frequency of the LPF43 is made as close as possible to the frequency 0 Hz, blocking the output of the voltage signal S2 based on the alternating current signal S1 and allowing only the voltage signal S2 based on the direct current Ib to pass through, and the cancellation current Ic can be supplied to the magnetic flux cancellation winding W1 in a direction to cancel the magnetic flux Mb, and moreover, it is configured at low cost. Further, since the input to the voltage driver 42 of the voltage signal generated in the magnetic flux cancellation winding W1 based on the magnetic flux Mc generated in the magnetic core 2 by the supply to the signal injection winding W2 of the alternating current signal S1 is blocked, a decrease in the level of the injection current Ii (alternating current signal S1) injected into the injection target line L based on the magnetic flux Mc generated in the magnetic core 2 is avoided. Note that the LPF43 can employ low-pass filters with various configurations in addition to the L-type LC filter shown in FIG. 1. For example, as shown in FIG. 7, between the input terminal Ti and the output terminal To, the above inductor L1 and an inductor L2 with a small inductance are connected in series, and the above capacitor C1 is connected between the connection point of the inductors L2 and L1 and the reference potential, and it may be configured by a T-type LC filter. Also, although not shown, it may be configured by a π-type LC filter. Further, regarding the LPF43 in each of the magnetic flux cancellation sections 4A, 4B, 4C described later and the LPF48 in the magnetic flux cancellation section 4D, since the function of avoiding a decrease in the level of the injection current Ii is not required, for the internal inductor L1, instead of a reactor with a large inductance, an inductor with a small inductance can be used. Also, the configurations of the LPF43 in each of the magnetic flux cancellation sections 4, 4A, 4B, 4C and the LPF48 in the magnetic flux cancellation section 4D are not limited to LC-type low-pass filters such as L-type, T-type, and π-type, and various low-pass filters such as RC-type low-pass filters of L-type, T-type, and π-type using a resistor instead of an inductor can be employed.Further, the frequency characteristics of the LPF 43 match the frequency characteristics indicating the ability to cancel the magnetic flux generated in the magnetic core 2 by the magnetic flux cancellation unit 4.

[0067] Also, the direction in which the cancellation current Ic flows and the winding direction of the magnetic flux cancellation winding W1 are preset so as to generate a magnetic flux Md in a direction that reduces the magnetic flux Mb generated in the magnetic core 2 when the direct current Ib supplied from the battery Bat to the load Load flows. Therefore, the voltage driver 42 of the magnetic flux cancellation unit 4 generates a voltage signal S2 (cancellation current Ic) such that the magnitude of the magnetic flux Mb detected by the Hall element 41 becomes zero and supplies it to the magnetic flux cancellation winding W1 wound around the magnetic core 2, thereby avoiding magnetic saturation of the magnetic core 2 caused by the flow of the large direct current Ib in the injection target line L. As a result, by supplying the alternating current signal S1 to the signal injection winding W2, the magnetic flux Mc is surely generated in the magnetic core 2, and the alternating current signal S1 is surely injected into the injection target line L.

[0068] The non-contact current sensor 5 is a so-called clamp-type current sensor, which functions as a non-contact current detection unit and a signal detection unit. This non-contact current sensor 5 detects, without contact, an injection current Ii, which is an alternating current flowing through the injection target line L, with respect to the injection target line L (the core wire (conductive wire) of the injection target line L), and outputs a detection signal S3, which is a current detection signal indicating the current value of the injection current Ii, to the processing unit 7. As shown in FIG. 8, this non-contact current sensor 5 includes a pair of semi-circular magnetic cores 5a, 5a, a single winding 5b wound around the magnetic cores 5a, 5a and composed of an insulated coated wire, and a current detection circuit 5c. In this non-contact current sensor 5, the pair of magnetic cores 5a, 5a are configured to be openable and closable. When clamping the injection target line L, the injection target line L is made to enter through the opening part of the magnetic cores 5a, 5a that are in the open state by operating an operation switch (not shown), and then, by operating the operation switch to make the magnetic cores 5a, 5a in the closed state (annular shape), the injection target line L is clamped by the magnetic cores 5a, 5a. In a state where the injection target line L is clamped, a magnetic flux whose magnitude changes according to the magnitude of the current flowing through the injection target line L is generated in the magnetic cores 5a, 5a, and a current whose magnitude changes according to the magnitude of the magnetic flux is output from the winding 5b. The current detection circuit 5c generates the detection signal S3 by converting the current output from the winding 5b into a voltage and outputs it to the processing unit 7. Note that the magnetic cores 5a, 5a and the winding 5b that forms a secondary winding magnetically coupled to the injection target line L as a primary winding constitute a secondary winding component CP2 corresponding to "a secondary winding component in a signal detection unit formed separately from the signal injection unit". Further, the secondary winding component CP2 can also be composed of only an air-core coil.

[0069] The voltage detection unit 6 includes a pair of contact-type probes P1 and P2, a buffer circuit 61, and an insulation circuit 62, and detects the voltage across the battery Bat and outputs a voltage signal S4 across both ends as a voltage detection signal to the processing unit 7. In this case, the buffer circuit 61 is an example of a voltage detection circuit, and includes coupling capacitors that block the input of a DC voltage and enable the input of an AC voltage at a pair of input parts respectively, generates a differential voltage of the AC voltage detected by the probes P1 and P2, and outputs a voltage signal S4 across both ends as the voltage across the battery Bat. Also, the insulation circuit 62 insulates the reference potential (ground) of the circuit including the load Load, the battery Bat, and the buffer circuit 61 from the reference potential (floating ground) of the impedance measurement device 1 excluding the buffer circuit 61, and outputs the voltage signal S4 across both ends in an insulated state to the processing unit 7.

[0070] The processing unit 7 is configured by, for example, a CPU, and includes A / D conversion circuits 71 to 73, a phase shift circuit 74, quadrature detection circuits 75 and 76, an arithmetic circuit 77, and an internal memory 78. The processing unit 7 inputs a detection signal S3 (current detection signal) and a voltage signal S4 across both ends (voltage detection signal), and measures the internal impedance Zb of the battery Bat that is the measurement object based on the detection signal S3 and the voltage signal S4 across both ends. In this case, the A / D conversion circuit 71 inputs the AC signal S1 output from the signal generation circuit 31, performs A / D conversion (analog / digital conversion), and outputs signal data D11 (sinωt) indicating the voltage value, frequency, and phase of the sine-wave AC signal S1 to the phase shift circuit 74 and the quadrature detection circuits 75 and 76. The A / D conversion circuit 72 inputs the detection signal S3 output from the non-contact current sensor 5, performs A / D conversion, and outputs signal data D12 indicating the current value, frequency, and phase of the detection signal S3 (injected current Ii) to the quadrature detection circuit 75. The A / D conversion circuit 73 inputs the voltage signal S4 across both ends output from the insulation circuit 62, performs A / D conversion, and outputs signal data D13 indicating the voltage value, frequency, and phase of the voltage signal S4 across both ends to the quadrature detection circuit 76.

[0071] The phase shift circuit 74 receives the signal data D11(sinωt) output from the A / D conversion circuit 71, shifts the phase of the AC signal S1, which is a sine wave signal represented by the signal data D11, by 90°, generates a cosine wave signal, and generates signal data D11(cosωt) indicating the current value, frequency, and phase of the cosine wave signal, and outputs it to the quadrature detection circuits 75 and 76. The quadrature detection circuit 75 receives the signal data D12 indicating the detection signal S3 (AC current value of the injection current Ii) output from the A / D conversion circuit 72, and uses the signal data D11(sinωt) indicating the sine wave AC signal S1 output from the A / D conversion circuit 71 and the signal data D11(cosωt) indicating the cosine wave AC signal S1 output from the phase shift circuit 74 to perform quadrature detection on the signal data D12, generates current data Di indicating the in-phase component (I component: In-phse component) and the quadrature component (Q component: Quadrature component) of the current value of the injection current Ii as a complex number, and outputs it to the arithmetic circuit 77. The quadrature detection circuit 76 receives the signal data D13 indicating the both-end voltage signal S4 (voltage value of the AC voltage generated at both ends of the battery Bat due to the flow of the injection current Ii) output from the A / D conversion circuit 73, and uses the signal data D11(sinωt) indicating the sine wave AC signal S1 output from the A / D conversion circuit 71 and the signal data D11(cosωt) indicating the cosine wave AC signal S1 output from the phase shift circuit 74 to perform quadrature detection on the signal data D13, generates voltage data Dv indicating the in-phase component (I component: In-phse component) and the quadrature component (Q component: Quadrature component) of the voltage value of the both-end voltage signal S4 as a complex number, and outputs it to the arithmetic circuit 77.

[0072] The arithmetic circuit 77 inputs the current data Di output from the quadrature detection circuit 75 and the voltage data Dv output from the quadrature detection circuit 76, and calculates the internal impedance Zb of the battery Bat based on the current data Di and the voltage data Dv. Further, the arithmetic circuit 77 outputs the impedance data Dz indicating the internal impedance Zb of the battery Bat as a calculation result to the internal memory 78 for storage and also outputs it to the output unit 8. Also, the arithmetic circuit 77 outputs a control signal Sc1 to the signal injection unit 3 so that the current value of the injection current Ii detected by the non-contact current sensor 5 is within the target current value range (for example, 1 mA ± 0.1 mA) required for impedance measurement, and controls the signal level of the AC signal S1 output from the signal injection unit 3 (signal generation circuit 31). Specifically, based on the input current data Di (which may be the signal data D12 output from the A / D conversion circuit 72), the arithmetic circuit 77 monitors the current value (signal level of the AC signal S1) of the injection current Ii injected into the injection target line L, and outputs and controls the signal level of the AC signal S1 output from the signal injection unit 3 with the control signal Sc1. The internal memory 78 is composed of a semiconductor memory, a hard disk device, etc., and stores impedance data Dz and the like.

[0073] The output unit 8 is composed of a display device (display) such as a liquid crystal panel or an organic EL panel as an example, inputs the impedance data Dz output from the processing unit 7, and displays the internal impedance Zb of the battery Bat on the screen. Note that instead of the display device, the output unit 8 can also be configured as an interface device that performs data communication with an external device and outputs the impedance data Dz to this external device.

[0074] Next, the measurement process for measuring the internal impedance Zb of the battery Bat as the measurement target by the impedance measurement device 1 will be described with reference to the accompanying drawings.

[0075] First, connect the battery Bat and the load Load with the injection target line L. When the load Load operates in this state, a large direct current Ib flows from the battery Bat to the load Load via the injection target line L. In this state, clamp the non-contact current sensor 5 to the injection target line L and contact the probes P1 and P2 to both ends of the battery Bat.

[0076] Next, operate a measurement start switch (not shown). Thereby, the processing unit 7 controls the signal generation circuit 31 to generate an alternating current signal S1. At this time, the signal generation circuit 31 generates the alternating current signal S1 while sweeping the frequency, outputs the generated alternating current signal S1 to the processing unit 7, and supplies the D-class amplified alternating current signal S1 to the signal injection winding W2. In this case, by supplying the alternating current signal S1 to the signal injection winding W2, an alternating current Iac flows through the signal injection winding W2, a magnetic flux Mc based on the alternating current signal S1 is generated in the magnetic core 2 in the direction shown in FIG. 1, and an injection current Ii, which is an alternating current signal with a current value corresponding to the magnitude of the magnetic flux Mc, is injected into the injection target line L. Therefore, the alternating current signal S1 is injected into the core wire of the injection target line L in a non-contact state via the signal injection winding W2.

[0077] Further, when a direct current Ib flows through the magnetic core 2, the magnetic flux cancellation unit 4 generates, by the zero-flux method, a magnetic flux Md as a second magnetic flux in the direction opposite to the magnetic flux Mb, which is the first magnetic flux generated in the direction shown in FIG. 1 in the magnetic core 2, to cancel the magnetic flux Mb. Specifically, the Hall element 41 outputs a voltage signal S2 corresponding to the magnetic flux generated in the magnetic core 2 to the voltage driver 42. Next, the voltage driver 42 amplifies the voltage signal S2 and outputs it to the LPF 43 with a low impedance. Also, the LPF 43 blocks the output of the voltage signal S2 (the voltage signal S2 based on the magnetic flux Mc) based on the alternating current signal S1 included in the voltage signal S2 amplified by the voltage driver 42, and passes the voltage signal S2 based on the direct current Ib to supply a cancellation current Ic in a direction to cancel the magnetic flux Mb to the magnetic flux cancellation winding W1, and blocks the input of the voltage signal generated in the magnetic flux cancellation winding W1 to the voltage driver 42 due to the supply of the alternating current signal S1 to the signal injection winding W2. Therefore, the voltage driver 42 generates a cancellation current Ic such that the magnitude of the magnetic flux Mb detected by the Hall element 41 becomes zero without flowing a cancellation current that attempts to cancel the magnetic flux Mc based on the alternating current signal S1 generated in the magnetic core 2, and supplies it to the magnetic flux cancellation winding W1. As a result, magnetic saturation of the magnetic core 2 caused by the flow of the large direct current Ib through the injection target line L is avoided. Also, since the input of the voltage signal generated in the magnetic flux cancellation winding W1 to the voltage driver 42 based on the magnetic flux Mc generated in the magnetic core 2 by the supply of the alternating current signal S1 to the signal injection winding W2 is blocked by the LPF 43, a decrease in the level of the injection current Ii (alternating current signal S1) injected into the injection target line L based on the magnetic flux Mc generated in the magnetic core 2 is avoided. As a result, when the alternating current signal S1 is supplied to the signal injection winding W2, the magnetic flux Mc is surely generated in the magnetic core 2, and the alternating current signal S1 is surely and efficiently injected into the injection target line L.

[0078] On one hand, in a state where an AC signal S1 is injected into the injection target line L and a DC current Ib is flowing, the non-contact current sensor 5 non-contactly detects the injection current Ii flowing through the injection target line L with respect to the injection target line L, and outputs a detection signal S3 indicating the current value to the processing unit 7.

[0079] Also, the buffer circuit 61 of the voltage detection unit 6 inputs the voltage at both ends of the battery Bat via a pair of probes P1, P2, and outputs a both-end voltage signal S4, which is the differential voltage of the AC voltage, to the insulation circuit 62. In this case, since the buffer circuit 61 is provided with coupling capacitors at a pair of input parts, only the differential voltage of the AC voltage detected by the probes P1, P2 is generated, and the both-end voltage signal S4 as the both-end voltage of the battery Bat is output. Next, the insulation circuit 62 outputs the both-end voltage signal S4 to the processing unit 7. At this time, the insulation circuit 62 outputs the both-end voltage signal S4 to the processing unit 7 in a state where the reference potential (ground) on the load Load and battery Bat sides is insulated from the reference potential (floating ground) of the impedance measurement device 1. As a result, by outputting the both-end voltage signal S4 to the impedance measurement device 1 via the insulation circuit 62, even if the output voltage of the battery Bat is a very high voltage, it is possible to accurately detect the minute AC voltage generated in the battery Bat when the AC signal S1 flows through the battery Bat.

[0080] On one hand, in the processing unit 7, when the A / D conversion circuit 71 receives the AC signal S1 and performs A / D conversion, it outputs signal data D11(sinωt) indicating the voltage value, frequency, and phase of the sine-wave AC signal S1 to the phase-shifting circuit 74 and the quadrature detection circuits 75 and 76. Further, when the A / D conversion circuit 72 receives the detection signal S3 and performs A / D conversion, it outputs signal data D12 indicating the current value, frequency, and phase of the detection signal S3 to the quadrature detection circuit 75. Also, when the A / D conversion circuit 73 receives the two-terminal voltage signal S4 and performs A / D conversion, it outputs signal data D12 indicating the voltage value, frequency, and phase of the two-terminal voltage signal S4 to the quadrature detection circuit 76. Additionally, when the phase-shifting circuit 74 receives the signal data D11, it shifts the phase of the AC signal S1, which is a sine-wave signal represented by the signal data D11, by 90° to generate a cosine-wave signal, and generates signal data D11(cosωt) indicating the current value, frequency, and phase of the cosine-wave signal and outputs it to the quadrature detection circuits 75 and 76.

[0081] Also, the quadrature detection circuit 75 inputs the signal data D12 indicating the detection signal S3, and quadrature-detects the signal data D12 with the signal data D11(sinωt) indicating the AC signal S1 of a sine wave and the signal data D11(cosωt) indicating the AC signal S1 of a cosine wave, generates current data Di indicating the in-phase component and the quadrature component of the current value of the injection current Ii in complex numbers, and outputs the current data Di to the arithmetic circuit 77. Further, the quadrature detection circuit 76 inputs the signal data D13 indicating the both-end voltage signal S4, and quadrature-detects the signal data D13 with the signal data D11(sinωt) and the signal data D11(cosωt), generates voltage data Dv indicating the in-phase component and the quadrature component of the voltage value of the both-end voltage signal S4 in complex numbers, and outputs the voltage data Dv to the arithmetic circuit 77. Next, the arithmetic circuit 77 inputs the current data Di and the voltage data Dv, calculates the internal impedance Zb of the battery Bat based on the current data Di and the voltage data Dv, outputs the impedance data Dz to the internal memory 78 for storage, and outputs the impedance data Dz to the output unit 8. At this time, the output unit 8 inputs the impedance data Dz and displays the internal impedance Zb of the battery Bat on the screen of the display device. Note that the arithmetic circuit 77 can also display the frequency characteristics of the internal impedance Zb of the battery Bat with respect to the frequency of the AC signal S1 on the screen of the display device by including the frequency information of the AC signal S1 in the impedance data Dz. Further, the arithmetic circuit 77 generates current value information of the DC current Ib flowing through the injection target line L based on the input current data Di (which may be the signal data D12 output from the A / D conversion circuit 72), and can also display the characteristics of the internal impedance Zb of the battery Bat with respect to the current value of the DC current Ib on the screen of the display device by including the current value information in the impedance data Dz.

[0082] Further, based on the input current data Di (which may be the signal data D12 output from the A / D conversion circuit 72), the arithmetic circuit 77 monitors the current value of the injection current Ii injected into the injection target line L, and outputs a control signal Sc1 so that the current value of the injection current Ii detected by the non-contact current sensor 5 is within the target current value range required for impedance measurement, thereby controlling the signal level of the AC signal S1 output from the signal injection unit 3. As a result, since the injection current Ii is within the target current value range, the ratio (S / N) of the signal level (S) to the noise level (N) of the detection signal S3 and the both-end voltage signal S4 can be increased. Therefore, in the arithmetic processing (measurement processing) of the internal impedance Zb performed by the arithmetic circuit 77, the internal impedance Zb can be accurately measured. Thereby, the measurement of the internal impedance Zb of the battery Bat by the impedance measurement device 1 is completed.

[0083] Note that the configuration of the "impedance measurement device" is not limited to the example of the impedance measurement device 1 described above. For example, for the magnetic flux cancellation unit 4, the configuration shown in FIG. 3 can be adopted. In the following description, for components having the same functions as the respective components in the impedance measurement device 1 described above, the same reference numerals are given and redundant descriptions are omitted.

[0084] The magnetic flux cancellation unit 4A shown in FIG. 3 includes a Hall element 41, a magnetic flux cancellation winding W1, an LPF 43, an addition circuit 44, and a voltage driver 42. In this case, one magnetic flux cancellation winding W1 has the functions of a cancellation winding and a signal injection winding. Further, the LPF 43 is an example of a filter circuit, has the same frequency characteristics as the LPF 43 of the magnetic flux cancellation unit 4, blocks the output of the voltage signal S2 based on the AC signal S1 included in the voltage signal S2 output from the Hall element 41, and passes the voltage signal S2 based on the DC current Ib. The addition circuit 44 adds the voltage signal S2 that has passed through the LPF 43 and the AC signal S1 to generate and output an addition signal Sa. The voltage driver 42 amplifies the addition signal Sa output from the addition circuit 44 and supplies it to the magnetic flux cancellation winding W1, supplies a cancellation current Ic to the magnetic flux cancellation winding W1 in a direction to cancel the magnetic flux Mb, and supplies the AC signal S1 (AC current Iac) to the magnetic flux cancellation winding W1 to inject the AC signal S1 into the injection target line L.

[0085] In this signal injection device 10, the voltage driver 42 amplifies the addition signal Sa obtained by adding the voltage signal S2 and the AC signal S1 by the addition circuit 44 and supplies it to the magnetic flux cancellation winding W1, so that the cancellation current Ic and the AC current Iac are added in the magnetic flux cancellation winding W1, and magnetic fluxes Md and Mc are generated in the magnetic core 2. Therefore, according to this signal injection device 10, it is possible to avoid magnetic saturation of the magnetic core 2 caused by the flow of the large DC current Ib through the injection target line L. As a result, by supplying the AC signal S1 (addition signal Sa) to the magnetic flux cancellation winding W1, the magnetic flux Mc can be surely generated in the magnetic core 2, and the AC signal S1 can be surely and efficiently injected into the injection target line L. Further, according to this signal injection device 10, since the functions of a cancellation winding and a signal injection winding can be realized using one magnetic flux cancellation winding W1, the signal injection device 10 can be configured at low cost.

[0086] Also, the magnetic flux cancellation section 4B shown in FIG. 4 includes a Hall element 41, a magnetic flux cancellation winding W1, an LPF 43, and a voltage driver 42. Further, the signal injection section 3A includes a voltage driver 32 in addition to the configuration of the above-described signal injection section 3. In this case, one magnetic flux cancellation winding W1 has the functions of a cancellation winding and a signal injection winding. Also, the LPF 43 is an example of a filter circuit and has the same frequency characteristics as the LPF 43 of the magnetic flux cancellation section 4, and blocks the output of the voltage signal S2 based on the AC signal S1 included in the voltage signal S2 output from the Hall element 41 and allows the voltage signal S2 based on the DC current Ib to pass through. The voltage driver 42 amplifies the voltage signal S2 that has passed through the LPF 43 and supplies a cancellation current Ic to one end T1 of the magnetic flux cancellation winding W1 in a direction to cancel the magnetic flux Mb. Also, the voltage driver 32 amplifies the AC signal S1 and supplies the amplified AC signal S1 (AC current Iac) to the other end T2 of the magnetic flux cancellation winding W1 to inject the AC signal S1 into the injection target line L.

[0087] In this signal injection device 10, the voltage driver 42 supplies a voltage signal S2 (cancellation current Ic) from one end T1 side of the magnetic flux cancellation winding W1 through the magnetic flux cancellation winding W1 toward the output section of the voltage driver 32, and the voltage driver 32 supplies an alternating current signal S1 (alternating current Iac) from the other end T2 side of the magnetic flux cancellation winding W1 through the magnetic flux cancellation winding W1 toward the output section of the voltage driver 42. As a result, the cancellation current Ic and the alternating current Iac are added in the magnetic flux cancellation winding W1, and magnetic fluxes Md and Mc are generated in the magnetic core 2. Therefore, according to this signal injection device 10, magnetic saturation of the magnetic core 2 caused by the flow of a large direct current Ib in the injection target line L can be avoided. As a result, by supplying the alternating current signal S1 to the magnetic flux cancellation winding W1, the magnetic flux Mc can be surely generated in the magnetic core 2, and the alternating current signal S1 can be surely and efficiently injected into the injection target line L. Further, according to this signal injection device 10, since the functions of the cancellation winding and the signal injection winding can be realized using one magnetic flux cancellation winding W1, the signal injection device 10 can be configured at low cost.

[0088] Also, the magnetic flux cancellation section 4C shown in FIG. 5 includes a Hall element 41, a magnetic flux cancellation winding W1, an LPF 43, and a current driver 45. In this case, the LPF 43 is an example of a filter circuit, has the same frequency characteristics as the LPF 43 of the magnetic flux cancellation section 4, blocks the output of the voltage signal S2 based on the alternating current signal S1 included in the voltage signal S2 output from the Hall element 41, and passes the voltage signal S2 based on the direct current Ib. The current driver 45 amplifies the voltage signal S2 that has passed through the LPF 43 and outputs the cancellation current Ic with a high output impedance in a direction to cancel the magnetic flux Mb and supplies it to the magnetic flux cancellation winding W1. Also, the signal injection section 3 includes a signal injection winding W2 wound around the magnetic core 2, in the same manner as the signal injection section 3 shown in FIG. 1, and supplies the alternating current signal S1 (alternating current Iac) to the signal injection winding W2 to inject the alternating current signal S1 into the injection target line L.

[0089] In this signal injection device 10, the current driver 45 supplies a voltage signal S2 (cancellation current Ic) to the magnetic flux cancellation winding W1 in a state of high output impedance. In this case, the signal injection unit 3 supplies an alternating current signal S1 to the signal injection winding W2, thereby generating a magnetic flux Mc in the magnetic core 2. At this time, although an alternating current based on the generated magnetic flux Mc tries to flow through the magnetic flux cancellation winding W1, due to the high output impedance of the current driver 45, the alternating current based on the magnetic flux Mc does not flow in the direction from the magnetic flux cancellation winding W1 toward the output section of the current driver 45. Therefore, without flowing a cancellation current that attempts to cancel the magnetic flux Mc generated by the alternating current signal S1 in the magnetic core 2, the current driver 45 generates a cancellation current Ic such that the magnitude of the magnetic flux Mb detected by the Hall element 41 becomes zero and supplies it to the magnetic flux cancellation winding W1. Therefore, according to this signal injection device 10, it is possible to avoid magnetic saturation of the magnetic core 2 caused by the flow of a large direct current Ib in the injection target line L. As a result, by supplying the alternating current signal S1 (alternating current Iac) to the signal injection winding W2, it is possible to surely generate the magnetic flux Mc in the magnetic core 2 and surely and efficiently inject the alternating current signal S1 into the injection target line L.

[0090] Further, according to the above signal injection device 10, by disposing any one of the Hall element 41, the fluxgate sensor, and the GMR element in the magnetic core 2 to form a magnetic flux detection circuit, it is possible to surely detect the magnetic flux Mb with a simple configuration.

[0091] In addition, by configuring the filter circuit with the LPF43 including an inductor formed of a reactor having a large inductance, the cut-off frequency can be made as close as possible to the frequency 0 Hz. As a result, only the voltage signal S2 based on the direct current Ib can be passed through, and it can be configured at low cost. Further, according to the signal injection device 10 having the magnetic flux canceling section 4, the input of the voltage signal generated in the magnetic flux canceling winding W1 to the voltage driver 42 based on the magnetic flux Mc generated in the magnetic core 2 by the supply of the alternating current signal S1 to the signal injection winding W2 is blocked by the LPF43. Therefore, it is possible to avoid a decrease in the level of the injection current Ii (alternating current signal S1) injected into the injection target line L based on the magnetic flux Mc generated in the magnetic core 2, and as a result, the alternating current signal S1 can be reliably and efficiently injected into the injection target line L.

[0092] Further, the magnetic flux canceling section 4D shown in FIG. 6 is configured to be able to avoid magnetic saturation of the magnetic core 2 caused by a large direct current Ib flowing through the injection target line L by supplying a canceling current Ic that reduces the signal level of the voltage signal S2 corresponding to the magnetic flux based on twice the frequency of the alternating current signal S1 generated in the magnetic core 2 to the magnetic flux canceling winding W1. In the signal injection device 10 using this magnetic flux canceling section 4D, since a magnetic flux detection circuit such as a Hall element 41 is not used, an annular core without a gap is used as the magnetic core 2. However, an annular core provided with a gap can also be used as the magnetic core 2.

[0093] Specifically, the signal injection device 10 shown in FIG. 6 is configured such that the signal generation circuit 31 of the signal injection section 3 includes a 2f signal generation circuit 31a and a 1 / 2 frequency division circuit 31b. In this case, the 2f signal generation circuit 31a generates a reference signal Sr for synchronous detection at twice the frequency of the alternating current signal S1. Further, the 1 / 2 frequency division circuit 31b generates the alternating current signal S1 to be injected into the injection target line L by frequency-dividing the reference signal Sr output from the 2f signal generation circuit 31a by 1 / 2.

[0094] On the one hand, the magnetic flux cancellation section 4D is configured to include a magnetic flux cancellation winding W1, an addition circuit 44, voltage drivers 42, 46, 49, a synchronous detection circuit 47, and an LPF 48. In this case, the synchronous detection circuit 47 synchronously detects a voltage signal S2 having a frequency twice that of the AC signal S1 (i.e., the distortion signal of the AC signal S1) included in the voltage signal S2 generated in the magnetic flux cancellation winding W1 with the reference signal Sr and outputs an output signal Sd. The LPF 48 is an example of a filter circuit, and extracts (passes) a DC signal Sdc generated based on the DC signal included in the output signal Sd of the synchronous detection circuit 47, that is, the harmonic signal having a frequency twice that of the distortion signal of the AC signal S1 (the frequency component same as the frequency reference signal Sr), and blocks the passage of AC signals such as frequency components twice or more the frequency of the reference signal Sr. The voltage driver 49 amplifies and outputs the DC signal Sdc output from the LPF 48. The addition circuit 44 adds the DC signal Sdc output from the amplifier circuit 49 and the AC signal S1 output from the signal generation circuit 31 (1 / 2 frequency division circuit 31b) and outputs an addition signal Sa. The voltage driver 42 amplifies the addition signal Sa output from the addition circuit 44 and supplies it to the magnetic flux cancellation winding W1.

[0095] In this signal injection device 10, a 2f signal generation circuit 31a in a signal generation circuit 31 of a signal injection unit 3 generates a reference signal Sr for synchronous detection and outputs it to a 1 / 2 frequency division circuit 31b and a synchronous detection circuit 47. Further, the 1 / 2 frequency division circuit 31b inputs the reference signal Sr, generates an AC signal S1 by performing 1 / 2 frequency division, and outputs it to an addition circuit 44 and an A / D conversion circuit 71 of a processing unit 7. On the other hand, in a magnetic flux cancellation unit 4D, a voltage driver 46 amplifies the input addition signal Sa and outputs it to the synchronous detection circuit 47. At this time, the synchronous detection circuit 47 performs synchronous detection of a voltage signal having a frequency twice that of the AC signal S1 generated in the magnetic flux cancellation winding W1 with the reference signal Sr, and outputs the voltage signal generated by the synchronous detection as an output signal Sd. Further, an LPF 48 extracts (passes) a DC signal Sdc (that is, a DC signal based on a harmonic signal having a frequency twice that of the distortion signal of the AC signal S1) included in the output signal Sd of the synchronous detection circuit 47 and blocks the passage of the AC signal. Next, a voltage driver 49 amplifies the DC signal Sdc output from the LPF 48 and outputs it to the addition circuit 44. At this time, the addition circuit 44 adds the DC signal Sdc output from the amplifier circuit 49 and the AC signal S1 output from the signal generation circuit 31 (1 / 2 frequency division circuit 31b) and outputs an addition signal Sa. Further, a voltage driver 42 amplifies the addition signal Sa output from the addition circuit 44 and supplies it to the magnetic flux cancellation winding W1. In this case, by the voltage driver 42 outputting the addition signal Sa, a cancellation current Ic based on the DC signal Sdc is supplied to the magnetic flux cancellation winding W1 in a direction to cancel the magnetic flux Mb, magnetic saturation of the magnetic core 2 is avoided, and the AC signal S1 (AC current Iac) is supplied to the magnetic flux cancellation winding W1, and the AC signal S1 is injected into the injection target line L. That is, in this magnetic flux cancellation unit 4D, without using a magnetic flux detection circuit such as a Hall element 41, it is overall feedback-controlled, and as a whole, it is flux-gate-sensitized to constitute the magnetic flux cancellation unit.

[0096] Therefore, according to this signal injection device 10, it is possible to avoid magnetic saturation of the magnetic core 2 caused by the flow of a large direct current Ib through the injection target line L. As a result, by supplying an alternating signal S1 (alternating current Iac) to the magnetic flux cancellation winding W1, a magnetic flux Mc can be surely generated in the magnetic core 2, and the alternating signal S1 can be surely and efficiently injected into the injection target line L. Further, in this signal injection device 10, the magnetic flux cancellation unit 4D is feedback-controlled as a whole so as to detect the magnitude of a harmonic signal having a frequency twice that of the alternating signal S1, which is a distortion signal of the alternating signal S1 generated in the magnetic core 2 in a magnetic saturation state, and reduce the distortion signal. For this reason, according to this signal injection device 10, since magnetic saturation of the magnetic core 2 can be directly detected, the magnetic flux Mc can be more surely generated without generating magnetic saturation in the magnetic core 2, and the alternating signal S1 can be more surely and efficiently injected into the injection target line L. Further, according to this signal injection device 10, since the functions of the cancellation winding and the signal injection winding can be realized using one magnetic flux cancellation winding W1, the signal injection device 10 can be configured at low cost.

[0097] In the magnetic flux cancellation unit 4D, when the necessary gain in each circuit is ensured, the arrangement of at least one of the voltage driver 46 and the voltage driver 49 can be omitted.

[0098] Next, an impedance measurement device 1A having a configuration in which the magnetic flux cancellation unit 4 is omitted will be described. Note that, for this impedance measurement device 1A, components having the same functions as those of the components in the impedance measurement device 1 described above are denoted by the same reference numerals, and redundant descriptions are omitted.

[0099] As shown in Fig. 9, the impedance measuring device 1A includes the magnetic core 2, signal injection unit 3, non-contact current sensor 5, voltage detection unit 6, processing unit 7, output unit 8, capacitor CL, and switch SL in the above-described impedance measuring device 1, and measures the internal impedance Zb of the battery Bat based on the detection signal S3 and the terminal voltage signal S4 in the same manner as the impedance measuring device 1.

[0100] Note that in this impedance measuring device 1, a magnetic core 2 in which the arrangement of the Hall element 41 and the magnetic flux cancellation winding W1 in the above-described impedance measuring device 1 is omitted can be used, or instead of the magnetic core 2, the magnetic core 2A shown in Figs. 10 to 12 can be used.

[0101] In this case, the magnetic core 2A is a first magnetic core and is composed of a plurality of C-shaped (i.e., C-shaped) unit magnetic cores UC having gaps G as shown in Figs. 10 to 12. In this example, for example, two unit magnetic cores UC are used, and in a top view of the two unit magnetic cores UC in a stacked state (see Fig. 11), two gaps G (the gap G of the upper unit magnetic core UC and the gap G of the lower unit magnetic core UC) adjacent to each other along the outer periphery of the magnetic core 2A are stacked so that the separation distance is equal. In this example, since two unit magnetic cores UC are used, the separation distance of the two gaps G is half the length of the outer periphery of the magnetic core 2A. However, when three unit magnetic cores UC are used, the separation distance of the three gaps G is one-third of the length of the outer periphery of the magnetic core 2A, and when four unit magnetic cores UC are used, the separation distance of the four gaps G is one-fourth of the length of the outer periphery of the magnetic core 2A.

[0102] Further, instead of the signal injection winding W2 as the primary winding component CP1 in the impedance measuring device 1, the primary winding component CP1A shown in FIG. 13 (hereinafter, when not distinguishing various primary winding components described later, also referred to as "primary winding component CP") can also be used. This primary winding component CP1A includes a signal injection winding W3 composed of an insulated coated wire (or enameled wire) wound around a magnetic core 2 (or magnetic core 2A). In this case, the signal injection winding W3 includes Na windings from the first winding to the Na-th winding (Na is an integer of 2 or more) that are connected in series as a whole and have different numbers of turns from each other, and Na switches from the first parallel switch to the Na-th parallel switch that are respectively connected in parallel to the first winding to the Na-th winding. Also, the first winding to the Na-th winding are each wound with a number of turns obtained by multiplying La (La is an integer of 1 or more) by Ma (Ma is Na integers from 0 to (Na - 1)). In this case, the start of winding Wb of the signal injection winding W3 is connected to the reference potential, and the end of winding We is connected to the output part of the signal generation circuit 31. Ma (Ma is Na integers from 0 to (Na - 1)) multiplied by La (La is an integer of 1 or more). In this case, the start of winding Wb of the signal injection winding W3 is connected to the reference potential, and the end of winding We is connected to the output part of the signal generation circuit 31.

[0103] Specifically, the primary winding component CP1A shown in the figure is configured by adopting, for example, 4 as the integer Na and 10 as the integer La. Therefore, the primary winding component CP1A includes four windings from the first winding Wd1 to the fourth winding Wd4 (hereinafter, also referred to as "winding Wd" when not distinguishing), and four switches from the first parallel switch SW1 to the fourth parallel switch SW4 (hereinafter, also referred to as "parallel switch SWa") that are respectively connected in parallel to the first winding Wd1 to the fourth winding Wd4. In this case, the parallel switch SWa may be composed of a semiconductor switch such as a transistor or FET, or may be composed of a mechanical switch such as a relay. Also, the first winding Wd1 to the fourth winding Wd4 are each wound around the magnetic core 2 (or magnetic core 2A) with 10 turns, 20 turns, 40 turns, and 80 turns, respectively.

[0104] Also, the first winding Wd1 to the fourth winding Wd4 are formed such that the wire diameter of the core wire in the insulated covered wire of the winding Wd with a larger number of turns is thinner than the wire diameter of the core wire in the insulated covered wire of the winding Wd with a smaller number of turns. In this case, since the impedance of the winding Wd with a larger number of turns increases and the current value of the alternating current Iac flowing through the injection target line L decreases, a thin insulated covered wire (or enameled wire) can be used, so that the productivity of the signal injection winding W3 is sufficiently improved.

[0105] On the other hand, in this impedance measuring device 1A, the processing unit 7 controls the on / off of the four parallel switches SW1 to SW4 by binary port control to change the number of turns of the primary winding component CP1A (signal injection winding W3) as a whole. Specifically, for each winding Wd, when the parallel switch SWa connected in parallel is controlled to be in the on state, both ends are short-circuited and the number of turns becomes 0 turns, and when the parallel switch SWa is controlled to be in the off state, both ends are opened and the original number of turns (number of windings) is obtained. Therefore, by the processing unit 7 (arithmetic circuit 77) outputting the control signal Sc2 to the four parallel switches SW1 to SW4 and controlling them individually to be on / off, the number of turns of the primary winding component CP1A as a whole can be changed in steps of 10 turns between 0 turns and 150 turns (substantially, from 10 turns to 150 turns). For example, as shown in FIG. 14, when the parallel switch SW3 is controlled to be in the on state and the parallel switches SW1, SW2, and SW4 are controlled to be in the off state, since the winding Wd3 is short-circuited, the signal injection winding W3 is controlled to have a total number of turns of 110 turns. Also, as shown in FIG. 15, when the parallel switches SW1, SW3, and SW4 are controlled to be in the on state and the parallel switch SW3 is controlled to be in the off state, since the windings Wd1, Wd3, and Wd4 are short-circuited, the signal injection winding W3 is controlled to have a total number of turns of 20 turns.

[0106] On the other hand, in order to include the current value of the injection current Ii indicated by the detection signal S3 output from the non-contact current sensor 5 within the target current value range, instead of, or in addition to, the process of outputting and controlling the control signal Sc1 for the signal level of the AC signal S1 output from the signal injection unit 3, the processing unit 7 (arithmetic circuit 77) outputs a control signal Sc2 to control the current value of the injection current Ii. Specifically, the processing unit 7 (arithmetic circuit 77) monitors the current value (signal level of the AC signal S1) of the injection current Ii injected into the injection target line L based on the input current data Di (which may also be the signal data D12 output from the A / D conversion circuit 72), and outputs a control signal Sc2 to change the number of turns of the signal injection winding W3, thereby controlling the current value of the injection current Ii. More specifically, the processing unit 7 (arithmetic circuit 77) obtains the load impedance (internal impedance Zb of the battery Bat and impedance of the load Load) as seen from the signal injection winding W3 when the load Load is connected to the battery Bat and in a closed-loop state based on the current value of the AC current Iac output from the signal generation circuit 31 and the current value of the injection current Ii detected by the non-contact current sensor 5 (the current value indicated by the current data Di or the signal data D12). On the other hand, when the load impedance is small, the processing unit 7 (arithmetic circuit 77) outputs a control signal Sc2 to control each parallel switch SWa, thereby increasing the total number of turns of the signal injection winding W3 to control so that more injection current Ii is easily injected. On the other hand, when the load impedance is large, the processing unit 7 (arithmetic circuit 77) outputs a control signal Sc2 to control each parallel switch SWa, thereby decreasing the total number of turns of the signal injection winding W3 to increase the electromotive force of the AC signal S1 in the signal injection winding W3 to control so that the injection current Ii is easily injected. Thereby, the processing unit 7 (arithmetic circuit 77) controls the number of turns of the signal injection winding W3 to an optimal number of turns, so as to include the magnitude of the injection current Ii injected into the injection target line L within the above-mentioned target current value range.

[0107] The capacitor CL is a capacitor connected in parallel across both ends of the load Load in the measurement system where the battery Bat as the measurement target and the load Load as the non-measurement target are connected in series on the injection target line L to form a circular closed loop. It has a function of short-circuiting the load Load when the impedance of the load Load is large. For example, a 100 μF multilayer capacitor is used. Also, the switch SL is connected in series with the capacitor CL and is controlled to be turned on and off by the processing unit 7. Then, the series circuit of the capacitor CL and the switch SL is connected in parallel across both ends of the load Load. Therefore, when the switch SL is controlled to be in the on state, the series circuit of the capacitor CL and the switch SL short-circuits both ends of the load Load. When the impedance of the load Load is large, the impedance of the entire closed loop composed of the battery Bat, the injection target line L, and the load Load also becomes large. In such a case, it becomes difficult to increase the current value (injection amount) of the injection current Ii when injecting the AC signal S1 into the injection target line L by the signal injection unit 3. For this reason, by short-circuiting both ends of the load Load with the capacitor CL, the impedance with respect to the AC signal S1 of the entire closed loop decreases, and the current value of the injection current Ii when injecting the AC signal S1 into the injection target line L by the signal injection unit 3 can be increased. Regarding this capacitor CL, a configuration can also be adopted in which probes provided at both ends of the capacitor CL are directly attached to both ends of the load Load without using the switch SL when the impedance of the load Load is large, or a configuration in which both lead wires of the capacitor CL are directly attached to both ends of the load Load can also be adopted.

[0108] Next, the operation of the impedance measurement device 1A will be described with reference to FIG. 9. Since the measurement process itself for measuring the internal impedance Zb of the battery Bat as the measurement target is the same as that of the impedance measurement device 1, duplicate explanations will be omitted and different processes will be described.

[0109] In this impedance measuring device 1A, in the arithmetic processing of impedance, in order for the processing unit 7 (arithmetic circuit 77) to include the current value of the injection current Ii indicated by the detection signal S3 output from the non-contact current sensor 5 within the target current value range, instead of, or in addition to, the process of outputting and controlling the control signal Sc1 for the signal level of the AC signal S1 output from the signal injection unit 3, the current value of the AC current Iac is output and controlled by the control signal Sc2. Specifically, based on the input current data Di (which may also be the signal data D12 output from the A / D conversion circuit 72), the arithmetic circuit 77 monitors the current value (signal level of the AC signal S1) of the injection current Ii injected into the injection target line L, and outputs the control signal Sc2 to change the number of turns of the signal injection winding W3, thereby controlling the current value of the injection current Ii.

[0110] More specifically, the arithmetic circuit 77 calculates the load impedance (the internal impedance Zb of the battery Bat and the impedance of the load Load) as seen from the signal injection winding W3 when the load Load is connected to the battery Bat and in a closed-loop state, based on the current value of the alternating current Iac output from the signal generation circuit 31 and the current value of the injection current Ii detected by the non-contact current sensor 5 (the current value indicated by the current data Di or the signal data D12). Next, when the load impedance is small, the arithmetic circuit 77 outputs a control signal Sc2 to control each parallel switch SWa, thereby increasing the total number of turns of the signal injection winding W3 so that more injection current Ii can be easily injected. On the other hand, when the load impedance is large, the arithmetic circuit 77 outputs a control signal Sc2 to control each parallel switch SWa, thereby decreasing the total number of turns of the signal injection winding W3 to increase the electromotive force of the alternating current signal S1 in the signal injection winding W3 so that the injection current Ii can be easily injected. Thereby, the arithmetic circuit 77 controls the number of turns of the signal injection winding W3 to an optimal number of turns, so that the magnitude of the injection current Ii injected into the injection target line L is included within the above-described target current value range. In this case, when changing (switching) the number of turns of the signal injection winding W3, the load fluctuation of the signal generation circuit 31 increases. However, since the final stage of the signal generation circuit 31 is composed of a class D amplifier section, the signal generation circuit 31 can maintain the output level of the alternating current signal S1 at a controlled constant level even against the load fluctuation.

[0111] Further, when the load impedance is large, the processing unit 7 (arithmetic circuit 77) controls the switch SL to be in the on state, instead of or in addition to, outputting the control signal Sc2, thereby short-circuiting both ends of the load Load with the capacitor CL. As a result, the AC impedance of the load Load decreases, and thus the current value of the alternating current Iac injected into the injection target line L increases.

[0112] In addition, in the configuration of the winding W3 for signal injection, the above integer Na is not limited to 4, and may be 2, 3, or 5 or more. Similarly, for the integer La, it is not limited to 10, and any integer of 1 or more can be adopted to form the primary winding component CP1A. Also, the first winding to the Na-th winding can be wound with the same number of turns.

[0113] Furthermore, for the primary winding component CP, instead of the magnetic cores 2 and 2A of the primary winding component CP1 or CP1A, as shown in FIG. 16, a primary winding component CP1B using an air-core coil AC configured to be able to insert the injection target line L can be adopted. Also, although not shown, as the primary winding component CP, a Rogowski coil configured by winding an insulated covered wire around an annular core material can also be used. By using these primary winding components CP, the AC signal S1 can be injected into the core wire of the injection target line L without contact, and the primary winding component CP can be configured at low cost. Also, since the primary winding component CP can be miniaturized, the primary winding component CP can be reliably and easily attached to the injection target line L arranged at a narrow measurement location.

[0114] Next, the impedance measuring device 1B will be described. This impedance measuring device 1B includes a plurality of primary winding components CP (in this example, 4 primary winding components CP1 and 2 primary winding components CP1B) corresponding to each of the frequency band groups obtained by grouping the frequency bands of the AC signal S1 generated by the signal injection unit 3 and injected into the injection target line L. Note that instead of the primary winding component CP1, the primary winding component CP1A can also be used. Also, since the impedance measuring device 1B performs the impedance measurement process itself in the same manner as the impedance measuring devices 1 and 1A, hereinafter, for the components having the same functions as the respective components in the above-described impedance measuring devices 1 and 1A, the same reference numerals will be given and redundant explanations will be omitted, and mainly, the configurations and operations different from those of the impedance measuring devices 1 and 1A will be described.

[0115] In the impedance measurement device 1B, as shown in FIG. 17, the signal injection unit 3 includes a signal generation circuit 31 having six output units Op1 to Op6 (hereinafter also referred to as "output unit Op" when not distinguished) that output an AC signal S1. In this case, the frequency band of the AC signal S1 is grouped into three frequency band groups FL, FM, and FH (hereinafter also referred to as "frequency band group F" when not distinguished). Here, as shown in FIG. 18, for example, the frequency band group FL on the low-frequency band side is defined in the range from the lower limit frequency f1 = 1 Hz to the upper limit frequency f2 = 50 KHz, the frequency band group FM on the middle-frequency band side is defined in the range from the lower limit frequency f2 = 50 KHz to the upper limit frequency f3 = 500 KHz, and the frequency band group FH on the high-frequency band side is defined in the range from the lower limit frequency f3 = 500 KHz to the upper limit frequency f4 = 10 MHz.

[0116] Also, a plurality (in this example, two examples are shown, but three or more may be used) of primary winding component parts CP1 respectively corresponding to frequency band groups FL are configured such that the magnetic core 2 (or magnetic core 2A) as the first magnetic core is composed of a metallic magnetic core, and a signal injection winding W2 (or signal injection winding W3) is wound around the magnetic core 2 (or magnetic core 2A) and they are configured with the same specifications. Also, a plurality (in this example, two examples are shown, but three or more may be used) of primary winding component parts CP1 respectively corresponding to frequency band groups FM are configured such that the magnetic core 2 (or magnetic core 2A) as the first magnetic core is composed of a ferrite magnetic core, and a signal injection winding W2 (or signal injection winding W3) is wound around the magnetic core 2 (or magnetic core 2A) and they are configured with the same specifications. Also, a plurality (in this example, two examples are shown, but three or more may be used) of primary winding component parts CP1B respectively corresponding to frequency band groups FH are composed of air-core coils AC with the same specifications formed by insulated coated wires. In this case, as the metallic magnetic core, any one of permalloy core, sendust core, amorphous core, powder core, pure iron, silicon steel sheet, permendur, nickel, cobalt, Fe-Si-Al, and electromagnetic stainless steel is used, and as the ferrite magnetic core, either Mn-Zn ferrite or Ni-Zn ferrite is used. Also, magnetic fluids or magnetic resins obtained by pulverizing metallic materials or ferrite materials and mixing them with oil or resin can also be used.

[0117] Also, the signal injection unit 3 is configured to be able to change the frequency of the AC signal S1, and in accordance with the control signal Sc1 output from the processing unit 7 (arithmetic circuit 77), when injecting an AC signal S1 having a frequency belonging to one frequency band group F, the AC signal S1 is output from two output units Op corresponding to that one frequency band group F, and the AC signal S1 is simultaneously applied to both ends of each of the two primary winding component parts CP.

[0118] Next, the operation of the impedance measurement device 1B will be described with reference to the accompanying drawings. Since the measurement process itself for measuring the internal impedance Zb of the battery Bat as the measurement target is the same as that of the impedance measurement devices 1 and 1A, duplicate explanations will be omitted and different processes will be described.

[0119] In this impedance measurement device 1B, in the impedance calculation process, when the processing unit 7 (calculation circuit 77) changes or sweeps the frequency of the AC signal S1, it outputs a control signal Sc1 to the signal injection unit 3 to specify the frequency of the AC signal S1 to be generated by the signal generation circuit 31. At this time, the signal generation circuit 31 outputs an AC signal S1 with the same frequency, the same phase, and the same signal level to the two output units Op corresponding to the frequency band group F to which the specified frequency belongs. Specifically, when the signal generation circuit 31 outputs an AC signal S1 with a frequency belonging to the frequency band group FL, it outputs the AC signal S1 to the two output units Op1 and Op2. Also, when the signal generation circuit 31 outputs an AC signal S1 with a frequency belonging to the frequency band group FM, it outputs the AC signal S1 to the two output units Op3 and Op4. Further, when the signal generation circuit 31 outputs an AC signal S1 with a frequency belonging to the frequency band group FH, it outputs the AC signal S1 to the two output units Op5 and Op6. Thereby, the AC signal S1 is injected into the injection target line L through the two primary winding component parts CP.

[0120] Note that when the signal generation circuit 31 switches from one primary winding component part CP to another primary winding component part CP and outputs the AC signal S1, the load fluctuation of the signal generation circuit 31 becomes large. However, since the final stage of the signal generation circuit 31 is composed of a class D amplifier section, the signal generation circuit 31 can maintain the output level of the AC signal S1 at a controlled constant level even against load fluctuations.

[0121] Further, when the processing unit 7 (arithmetic circuit 77) causes the signal generation circuit 31 to change (or sweep) the frequency of the AC signal S1 from one frequency band group F to the other frequency band group F at the boundary of two frequency band groups F whose frequency bands of the AC signal S1 are adjacent to each other, the AC signal S1 is applied to two primary winding component parts CP corresponding to the two adjacent frequency band groups F.

[0122] Specifically, as shown in FIG. 18, when the processing unit 7 (arithmetic circuit 77) causes the frequency of the AC signal S1 to change (or sweep) from the frequency band group FL to the frequency band group FM, and when the frequency of the AC signal S1 is caused to change (or sweep) from the frequency band group FM to the frequency band group FL, the control signal Sc1 is output to the signal generation circuit 31, so that at the boundary FLM of the range from a frequency that is lower than the frequency f2 by the frequency α1 (for example, -10% with respect to the frequency f2) to a frequency that is higher than the frequency f2 by the frequency α2 (for example, +10% with respect to the frequency f2), the AC signal S1 is output to two primary winding component parts CP corresponding to the two adjacent frequency band groups F. As a result, the signal generation circuit 31 outputs the AC signal S1 having the same frequency, the same phase, and the same signal level (it may be controlled to 1 / 2 of the signal level at frequencies other than the boundary FLM) from the four output parts Op1, Op2, Op3, Op4. As a result, at the boundary FLM, since two types of magnetic cores 2 (or magnetic cores 2A) of materials suitable for coupling with the injection target line L are used according to the frequency of the AC signal S1, the AC signal S1 is sufficiently efficiently injected into the injection target line L.

[0123] Similarly, as shown in FIG. 18, when the processing unit 7 (arithmetic circuit 77) changes (or sweeps) the frequency of the AC signal S1 from the frequency band group FM to the frequency band group FH, and when changing (or sweeping) the frequency of the AC signal S1 from the frequency band group FH to the frequency band group FM, the control signal Sc1 is output to the signal generation circuit 31, so that at the boundary FMH of the range from a frequency that is lower than the frequency f3 by a frequency α3 (e.g., -10% with respect to the frequency f3) to a frequency that is higher than the frequency f3 by a frequency α4 (e.g., +10% with respect to the frequency f3), the AC signal S1 is output to the two primary winding component parts CP corresponding to the two adjacent frequency band groups F. As a result, the signal generation circuit 31 outputs the AC signal S1 with the same frequency, the same phase, and the same signal level (which may be controlled to 1 / 2 of the signal level at frequencies other than the boundary FMH) from the four output parts Op3, Op4, Op5, and Op6. As a result, at the boundary FLM, since the magnetic core 2 (or magnetic core 2A) and the air-core coil AC that are suitable for coupling with the injection target line L are used according to the frequency of the AC signal S1, the AC signal S1 is injected into the injection target line L with sufficient efficiency.

[0124] Note that the frequency band grouping is not limited to three, and it may be grouped into two frequency band groups. In that case, as an example, the magnetic core 2 (or magnetic core 2A) in the primary winding component part CP1 corresponding to the low-frequency band group FL on the low-frequency band side of the two frequency band groups is composed of a metal-based magnetic core, and the magnetic core 2 (or magnetic core 2A) in the primary winding component part CP1 corresponding to the high-frequency band group FM on the high-frequency band side of the two frequency band groups is composed of a ferrite-based magnetic core.

[0125] Further, as another example, the magnetic core 2 (or magnetic core 2A) in the primary winding component CP1 corresponding to the low-frequency band group FM on the low-frequency band side of the two frequency band groups may be composed of a metal-based magnetic core or a ferrite-based magnetic core, and the primary winding component corresponding to the high-frequency band group FH on the high-frequency band side of the two frequency band groups may be composed of the primary winding component CP1B of the air-core coil AC.

[0126] Next, an impedance measuring device 1C having a plurality of voltage detection units 6 will be described. Note that this impedance measuring device 1C differs from the impedance measuring devices 1, 1A, and 1B described above in that it has a plurality of voltage detection units 6 and the processing unit 7A is configured to be able to simultaneously measure the impedances of a plurality of measurement targets. Therefore, hereinafter, mainly, the configurations and operations different from those of the impedance measuring devices 1, 1A, and 1B will be described.

[0127] As shown in Fig. 19, the impedance measurement device 1C includes a plurality of voltage detection units 6 (three in this figure: voltage detection unit 6-1, voltage detection unit 6-2, and voltage detection unit 6-3) having the same configuration and the same function as the above-described voltage detection unit 6. Hereinafter, when the three voltage detection units 6-1, 6-2, and 6-3 are not distinguished, they are also referred to as "voltage detection unit 6". In this case, the three voltage detection units 6 are connected in series to the injection target line L and detect the voltage values of the AC signals S1 generated at both ends of a plurality of battery cells (three battery cells Cel1 to Cel3 in this figure: hereinafter, when not distinguished, also referred to as "battery cell Cel") among a large number of battery cells of the battery Bat as the measurement target, and output the both-end voltage signals S4 to the processing unit 7A respectively. Each voltage detection unit 6 includes a pair of contact-type probes P1 and P2, a buffer circuit 61, and an insulation circuit 62. The illustration of the buffer circuit 61 and the insulation circuit 62 is omitted. Hereinafter, when the three sets of probes P1 and P2 are distinguished, they are referred to as "probe P1-1, probe P1-2, probe P1-3, probe P2-1, probe P2-2, and probe P2-3", and when not distinguished, they are also referred to as "probes P1, P2".

[0128] The processing unit 7A is composed of, for example, a CPU, and includes A / D conversion circuits 71 and 72, three A / D conversion circuits 73-1, 73-2, and 73-3 (hereinafter, when not distinguished, also referred to as "A / D conversion circuit 73") having the same configuration and the same function as the above-described A / D conversion circuit 73, a phase shift circuit 74, a quadrature detection circuit 75, three quadrature detection circuits 76-1, 76-2, and 76-3 (hereinafter, when not distinguished, also referred to as "quadrature detection circuit 76") having the same configuration and the same function as the above-described quadrature detection circuit 76, an arithmetic circuit 77, and an internal memory 78. The processing unit 7A inputs the detection signal S3 (current detection signal) and a plurality (three in this example) of both-end voltage signals S4 (voltage detection signals), and simultaneously measures the internal impedances Zc1, Zc2, and Zc3 (hereinafter, when not distinguished, also referred to as "internal impedance Zc") of the three battery cells Cel1 to Cel3 that are the measurement target based on the detection signal S3 and the three both-end voltage signals S4.

[0129] Next, a measurement process for measuring the internal impedance Zc of each battery cell Cel in the battery Bat as a measurement target by the impedance measurement device 1C will be described.

[0130] First, the non-contact current sensor 5 is clamped to the injection target line L, and the probes P1-1 and P2-1 are respectively connected (connected) to both ends of the battery cell Cel1, the probes P1-2 and P2-2 are respectively connected (connected) to both ends of the battery cell Cel2, and the probes P1-3 and P2-3 are respectively brought into contact (connected) with both ends of the battery cell Cel3.

[0131] During the impedance measurement process, each voltage detection unit 6 inputs the voltage at both ends of each battery cell Cel via a pair of probes P1 and P2, and outputs the both-end voltage signal S4, which is the differential voltage of the alternating voltage, to the processing unit 7 respectively.

[0132] On the other hand, in the processing unit 7, the A / D conversion circuit 71 inputs the alternating current signal S1, performs A / D conversion, and outputs the signal data D11(sinωt) to the phase shift circuit 74, the quadrature detection circuit 75, and each quadrature detection circuit 76. Also, the A / D conversion circuit 72 inputs the detection signal S3, performs A / D conversion, and outputs the signal data D12 to the quadrature detection circuit 75. Also, each of the A / D conversion circuits 73-1, 73-2, 73-3 inputs the both-end voltage signal S4, performs A / D conversion, and outputs the signal data D13-1, D13-2, D13-3 (hereinafter also referred to as "signal data D13" when not distinguished) to the corresponding quadrature detection circuits 76-1, 76-2, 76-3 respectively. Also, the phase shift circuit 74 inputs the signal data D11, generates the signal data D11(cosωt), and outputs it to the quadrature detection circuit 75 and each quadrature detection circuit 76.

[0133] In addition, the quadrature detection circuit 75 inputs the signal data D12, generates the current data Di, and outputs it to the arithmetic circuit 77. Further, each of the quadrature detection circuits 76-1, 76-2, 76-3 inputs the signal data D13, generates the voltage data Dv-1, Dv-2, Dv-3 (hereinafter also referred to as "voltage data Dv" when not distinguished), and outputs them to the arithmetic circuit 77 respectively. Next, the arithmetic circuit 77 inputs the current data Di and each voltage data Dv, calculates the internal impedance Zc1 of the battery cell Cel1 based on the current data Di and the voltage data Dv-1, calculates the internal impedance Zc2 of the battery cell Cel2 based on the current data Di and the voltage data Dv-2, and calculates the internal impedance Zc3 of the battery cell Cel3 based on the current data Di and the voltage data Dv-3, outputs the impedance data Dz to the internal memory 78 for storage, and outputs it to the output unit 8. At this time, the output unit 8 inputs the impedance data Dz and displays the internal impedances Zc1, ZC2, Zc3 of the respective battery cells Cel1, Cel2, Cel3 on the screen of the display device.

[0134] Next, the impedance measuring device 1D will be described. As shown in FIG. 20, this impedance measuring device 1D includes a primary winding component CP1C in which a signal injection unit 3 has a magnetic core 2 (or magnetic core 2A), a signal injection winding W2 (or signal injection winding W3) wound around the magnetic core 2 (or magnetic core 2A), a capacitor circuit CS, and a damping resistor R1. Further, the signal injection unit 3 includes a signal generation circuit 31A. Note that this impedance measuring device 1D is different from the impedance measuring devices 1, 1A, 1B, and 1C described above in that it includes the primary winding component CP1C having the capacitor circuit CS and the damping resistor R1, and in that it includes the signal generation circuit 31A instead of the signal generation circuit 31 described above. For other configurations and functions, it is provided in the same manner as the impedance measuring devices 1, 1A, 1B, and 1C. Therefore, hereinafter, components having the same functions as the respective components in the impedance measuring devices 1, 1A, 1B, and 1C described above will be denoted by the same reference numerals, and duplicate explanations will be omitted. Mainly, the configurations and operations different from those of the impedance measuring devices 1, 1A, 1B, and 1C will be described.

[0135] The primary winding component CP1C includes a capacitor circuit CS that forms an LC parallel resonance circuit (an example of an LC resonance circuit) RC1 together with the signal injection winding W2 (or the signal injection winding W3) as the primary winding. In this case, the LC parallel resonance circuit RC1 is arranged as the load circuit of the FET1 to be described later. Also, the LC parallel resonance circuit RC1 has a resonance point at the frequency of the AC signal S1 or a frequency in the vicinity thereof (that is, for example, when the frequency of the AC signal S1 is 10 kHz, a frequency between 9.5 kHz and 10.5 kHz (a frequency range of approximately ±5% with respect to the frequency of the AC signal S1)). The inductance of the signal injection winding W2 (or the signal injection winding W3) and the capacitance of the capacitor circuit CS are determined accordingly. In this case, since the LC parallel resonance circuit RC1 functions as the primary winding with respect to the injection target line L as the secondary winding, only the fundamental wave of the AC signal S1, which is a signal having the same or a frequency in the vicinity of the resonance frequency of the LC parallel resonance circuit RC1, is transmitted to the injection target line L by parallel resonance. Therefore, when the AC signal S1 of the pulse signal is class-D amplified by the FET1 as described later, only the sine-wave AC signal S1 is transmitted to the injection target line L without transmitting the harmonics of the AC signal S1. That is, the LC parallel resonance circuit RC1 has a function of linearly amplifying the sine-wave AC signal S1 with respect to the FET1.

[0136] Also, the primary winding component CP1C also includes a damping resistor R1 that reduces the Q value of the resonance in the LC parallel resonance circuit RC1. In this case, the capacitor circuit CS and the damping resistor R1 are each connected in parallel with the signal injection winding W2 (or the signal injection winding W3). Also, the resistance value of the damping resistor R1 is defined as, for example, 10 KΩ. However, for this damping resistor R1, instead of a fixed resistor with a fixed resistance value, a variable resistor with a variable resistance value that can arbitrarily vary the Q value of the resonance can also be employed. Also, when it is necessary to increase the Q value of the resonance in the LC parallel resonance circuit RC1, the arrangement of the damping resistor R1 can also be omitted.

[0137] The capacitor circuit CS is configured to include Nb capacitors from the first capacitor to the Nb-th capacitor (Nb is an integer of 2 or more) that are connected in parallel as a whole and have different capacitances from each other, and Nb switches from the first series switch to the Nb-th series switch that are respectively connected in series to the first capacitor to the Nb-th capacitor. Also, the first capacitor to the Nb-th capacitor are each defined as a capacitance multiplied by a specific capacitance (for example, "0.025 μF") by 2 Mb (Mb is Nb integers from 0 to (Nb - 1)). In this case, one end T11 of the capacitor circuit CS (one end of the LC parallel resonance circuit RC1) is connected to the output end of the LPF33 described later that is at a high potential, and the other end T12 of the capacitor circuit CS (the other end of the LC parallel resonance circuit RC1) is connected to the drain of the FET1.

[0138] Specifically, the primary winding component CP1C is configured by adopting, for example, 4 as the integer Nb. Therefore, as shown in FIG. 21, the primary winding component CP1C includes four capacitors from the capacitor C11 to the capacitor C14 (hereinafter also referred to as "capacitor Cb" when not distinguished), and four switches from the series switch SW11 to the series switch SW14 (hereinafter also referred to as "series switch SWb") that are respectively connected in series to the capacitor C11 to the capacitor C14. In this case, the series switch SWb may be configured by a semiconductor switch such as a transistor or an FET, or may be configured by a mechanical switch such as a relay. Also, as an example, the capacitors C11 to C14 each have capacitances of 0.025 μpF, 0.050 μpF, 0.100 μF, and 0.200 μF. Also, the integer Nb is not limited to 4, and numbers of 2, 3, and 5 or more can be adopted.

[0139] In this impedance measuring device 1D, the processing unit 7 controls the on / off states of four series switches SW11 to SW14 by binary port control to change the capacitance of the entire capacitor circuit CS. Specifically, when the series switch SWb connected in series corresponding to each capacitor Cb is controlled to be in the on state, the capacitance of that capacitor Cb is increased, and when the series switch SWb is controlled to be in the off state, the capacitance of that capacitor Cb is decreased. Therefore, by outputting the control signal Sc3 to the four series switches SW11 to SW14 and individually controlling their on / off states, the processing unit 7 (arithmetic circuit 77) can change the capacitance of the entire capacitor circuit CS in steps of 0.025 μF between 0 μF and 0.375 μF (substantially from 0.025 μF to 0.375 μF). For example, as shown in FIG. 22, when the series switches SW12 and SW14 are controlled to be in the on state and the series switches SW11 and SW13 are controlled to be in the off state, the capacitor circuit CS is controlled to have a total capacitance of 0.25 μF because the capacitances of the capacitors C12 and C14 increase. In this way, when sweeping the frequency of the AC signal S1, the processing unit 7 changes the capacitance of the entire capacitor circuit CS by port control so that the resonance frequency of the LC parallel resonance circuit RC1 becomes the same as or near the frequency of the AC signal S1.

[0140] As shown in Fig. 20, the signal generation circuit 31A includes an FET1, resistors R2 and R3, a low-pass filter 33 (hereinafter also referred to as "LPF33"), and a power supply circuit 34. The FET1 is an amplifier circuit that amplifies the AC signal S1 and is composed of an N-channel MOSFET. Also, for the FET1, the drain terminal is connected to the other end side of the LC parallel resonance circuit RC1, the source terminal is connected to the reference potential at a low potential, and the gate terminal is connected to a signal oscillator (not shown) that generates the AC signal S1. This FET1 receives the AC signal S1 of the pulse signal divided by the resistors R2 and R3 at the gate terminal and amplifies the AC signal S1 in class D. Note that a bipolar transistor can also be used instead of the FET. Also, instead of the configuration of the FET1 in this example, although not shown, an amplifier circuit with a push-pull configuration can also be configured using an FET or a bipolar transistor.

[0141] The LPF33 is configured such that its cut-off frequency is defined to allow the passage of the AC signal S1 (which is also a signal having the same frequency as the resonance frequency of the LC parallel resonance circuit RC1) and to block the passage of frequencies higher than the AC signal S1 (especially the harmonic signals of the AC signal S1), and is connected in series to the LC parallel resonance circuit RC1. The input terminal of this LPF33 is connected to the output section of the power supply circuit 34, and the output terminal is connected to the LC parallel resonance circuit RC1. Therefore, when the FET1 amplifies the AC signal S1 of the pulse signal in class D, the LPF33 blocks the passage to and from the power supply circuit 34 with respect to the frequencies of the harmonics of the AC signal S1, and substantially has a function of linearly (in a straight line) amplifying the sinusoidal AC signal S1 for the FET1 together with the LC parallel resonance circuit RC1.

[0142] The power supply circuit 34 is an output voltage variable type power supply device in which the voltage V as the high potential H is variable, and generates and outputs the voltage V according to the instruction by the control signal Sc1 output from the processing unit 7. In this case, the voltage V according to the instruction by the control signal Sc1 by the power supply circuit 34 H HBy outputting this, as a result of the change in the drain voltage of FET1, the voltage (which is also power) of the AC signal S1 output from FET1 can be freely changed.

[0143] Next, the operation of the impedance measurement device 1D will be described. Note that since the measurement process itself for measuring the internal impedance Zb of the battery Bat as the measurement target is the same as that of the impedance measurement devices 1, 1A, 1B, and 1C, duplicate explanations will be omitted and different processes will be described.

[0144] In this impedance measurement device 1D, in the impedance calculation process, the processing unit 7 (calculation circuit 77) outputs the control signal Sc1 to the signal generation circuit 31A of the signal injection unit 3 to control the signal level and frequency of the AC signal S1. At this time, the signal generation circuit 31A generates an AC signal S1 of a pulse signal having the frequency indicated by the control signal Sc1 as the fundamental wave and outputs it to FET1. Further, FET1 inputs the AC signal S1 divided by the resistors R2 and R3 to the gate terminal and amplifies the AC signal S1 in class D. Also, the power supply circuit 34 controls the voltage value of the voltage V H applied to the drain of FET1 so that the signal level of the AC signal S1 becomes the signal level indicated by the control signal Sc1. Thereby, FET1 of the signal generation circuit 31A generates and outputs an AC signal S1 having the signal level and frequency indicated by the control signal Sc1.

[0145] In this case, in a configuration where the LC parallel resonance circuit RC1 is not provided, when the frequency of the AC signal S1 is high, due to the inductance component of the signal injection winding W2 (or the signal injection winding W3), it becomes difficult for the AC signal S1 to flow through the signal injection winding W2 (or the signal injection winding W3). Also, when the distance between the signal injection winding W2 (or the signal injection winding W3) and the signal generation circuit 31A is long, due to the resistance value and inductance component of the lead wire, the loss of the AC signal S1 increases and the heat generation increases. Furthermore, due to flowing the AC signal S1 through the lead wire, the radio wave radiation of the harmonic wave of the AC signal S1 from the lead wire increases, and there is a possibility of violating the EMC standard (noise standard).

[0146] On the other hand, in this impedance measuring device 1D, since the LC parallel resonance circuit RC1 is provided, the processing unit 7 (arithmetic circuit 77) outputs the control signal Sc3 to the capacitor circuit CS, so that the four series switches SW11 to SW14 are turned on and off according to the frequency of the AC signal S1 generated by the signal generation circuit 31A, thereby changing the capacitance of the entire capacitor circuit CS. That is, the processing unit 7 (arithmetic circuit 77) changes the resonance frequency of the LC parallel resonance circuit RC1 to be the frequency of the AC signal S1 or a frequency in the vicinity thereof. In this case, when sweeping the frequency of the AC signal S1, the control signal Sc3 is sequentially output to the capacitor circuit CS so as to be the frequency of the AC signal S1 to be swept or the resonance frequency in the vicinity thereof.

[0147] Therefore, the impedance of the LC parallel resonance circuit RC1 at the frequency of the AC signal S1 increases, and the impedance of the LC parallel resonance circuit RC1 at the harmonic frequencies of the AC signal S1 decreases. As a result, the generation of harmonic distortion of the AC signal S1 in the current path including the LC parallel resonance circuit RC1 from the drain of the FET1 is suppressed. At the same time, since the impedance of the LPF 33 increases at the harmonic frequencies of the AC signal S1, the generation of harmonic distortion of the AC signal S1 is further suppressed. As a result, the FET1 outputs a sinusoidal AC signal S1. Also, even when the frequency of the AC signal S1 is high, since the inductance component of the signal injection winding W2 (or the signal injection winding W3) is extremely small, the AC signal S1 easily flows through the signal injection winding W2 (or the signal injection winding W3). As a result, the loss of the AC signal S1 in the LC parallel resonance circuit RC1 is sufficiently reduced. Also, even when the distance between the signal injection winding W2 (or the signal injection winding W3) and the signal generation circuit 31A is long, since the impedance of the LC parallel resonance circuit RC1 is large, the loss and heat generation of the AC signal S1 due to the resistance value and inductance component of the lead wire are reduced. Therefore, the configuration of the amplifier circuit including the FET1 is simplified. Furthermore, since the impedance of the LC parallel resonance circuit RC1 is large, the current value of the AC signal S1 flowing through the lead wire becomes small, and almost no harmonic components of the AC signal S1 are generated. As a result, the radio wave radiation of the harmonic of the AC signal S1 from the lead wire is sufficiently reduced, and the EMC standard (noise standard) is easily satisfied. Also, since the damping resistor R1 decreases the Q value of the resonance in the LC parallel resonance circuit RC1, the frequency characteristics of the LC parallel resonance circuit RC1 become broad. As a result, even if there is a slight difference between the frequency of the AC signal S1 generated by the signal generation circuit 31A and the resonance frequency of the LC parallel resonance circuit RC1, the above effects are sufficiently exhibited. Therefore, the sinusoidal AC signal S1 is efficiently injected into the injection target line L as the secondary winding via the signal injection winding W2 (or the signal injection winding W3) as the primary winding.

[0148] In this example, as an example, the capacitors C11 to C14 are each 2 Mb(Mb is an integer from 0 to 4), the capacitance is defined as the capacitance multiplied by 0.025 μF as a specific capacitance, so that the capacitance of the entire capacitor circuit CS can be finely controlled. On the other hand, since the capacitor circuit CS is composed of four capacitors C11 to C14, the frequency bandwidth of the sweepable AC signal S1 is small. Therefore, by providing a large number of capacitors Cb and the same number of series switches SWb as the number of capacitors, the frequency bandwidth of the sweepable AC signal S1 can be made sufficiently large. Also, a signal injection winding W3 can be wound around the magnetic core 2 (or magnetic core 2A), and the processing unit 7 (arithmetic circuit 77) can output a control signal Sc2 to control the parallel switches SW1 to SW4. In this configuration, since both the capacitance of the capacitors C11 to C14 of the LC parallel resonance circuit RC1 and the inductance of the signal injection winding W3 can be changed according to the frequency of the AC signal S1, the frequency bandwidth of the sweepable AC signal S1 can be made wider.

[0149] However, in order to change the resonance frequency of the LC parallel resonance circuit RC1, only the capacitance of the capacitor circuit CS may be changed, or only the inductance of the signal injection winding W3 may be changed using a capacitor with a fixed capacitance without using the capacitor circuit CS, or both the capacitance of the capacitor circuit CS and the inductance of the signal injection winding W3 may be changed. Also, by increasing the number of turns (Na) of the winding wound around the magnetic core 2 (or magnetic core 2A) and the number of series switches SWa (Na), the frequency bandwidth of the sweepable AC signal S1 can be further increased. In this case, by changing both the capacitance of the capacitor circuit CS and the inductance of the signal injection winding W3, or by increasing the number of turns (Na) of the winding wound around the magnetic core 2 (or magnetic core 2A) and the number of series switches SWa (Na), the resonance frequency can be linearly changed. Also, a BPF (band-pass filter) can be employed instead of the LPF33. In this configuration, the processing unit 7 (arithmetic circuit 77) adjusts the cut-off frequencies of the low and high bands of the BPF so as to be a frequency band that allows the passage of the AC signal S1. Furthermore, the arrangement of the LPF33 can be omitted. Also, the primary winding component CP1B can be used instead of the primary winding component CP1C. Also, when control of the signal level of the AC signal S1 is not required, the power supply circuit 34 can be configured with a power supply device with a fixed voltage.

[0150] Next, the impedance measurement device 1E will be described. As shown in FIG. 23, this impedance measurement device 1D includes a primary winding component CP1D in which a signal injection unit 3 includes a magnetic core 2 (or magnetic core 2A), a signal injection winding W2 (or signal injection winding W3) wound around the magnetic core 2 (or magnetic core 2A), a capacitor circuit CS, and a damping resistor R4. The signal injection unit 3 is configured to include a signal generation circuit 31B. Note that this impedance measurement device 1E differs from the impedance measurement device 1D described above in that it includes the primary winding component CP1D instead of the primary winding component CP1C, and includes the signal generation circuit 31B instead of the signal generation circuit 31A described above. For other configurations and functions, it is provided in the same manner as the impedance measurement devices 1, 1A, 1B, 1C, and 1D. Therefore, hereinafter, components having the same functions as the components in the impedance measurement devices 1, 1A, 1B, 1C, and 1D described above will be denoted by the same reference numerals, and redundant descriptions will be omitted. Mainly, the configurations and operations different from those of the impedance measurement devices 1, 1A, 1B, 1C, and 1D will be described.

[0151] The primary winding component CP1D includes the capacitor circuit CS described above that forms an LC series resonance circuit (an example of an LC resonance circuit) RC2 together with the signal injection winding W2 (or the signal injection winding W3) as the primary winding. In this case, the LC series resonance circuit RC2 is arranged as a load circuit for the FET2 and FET3 described later. Also, the inductance of the signal injection winding W2 (or the signal injection winding W3) and the capacitance of the capacitor circuit CS are determined so that the LC series resonance circuit RC2 has a resonance point at the frequency of the AC signal S1 or a frequency in the vicinity thereof (that is, for example, when the frequency of the AC signal S1 is 10 kHz, a frequency between 9.5 kHz and 10.5 kHz (a frequency in the range of approximately ±5% with respect to the frequency of the AC signal S1)). In this case, since the LC series resonance circuit RC2 functions as a primary winding with respect to the injection target line L as the secondary winding, only the fundamental wave of the AC signal S1, which is a signal having the same or a frequency in the vicinity of the resonance frequency of the LC series resonance circuit RC2, is transmitted to the injection target line L by series resonance. Therefore, when the AC signal S1 of the pulse signal is D-class amplified by the FET2 and 3 as described later, only the sine-wave AC signal S1 is transmitted to the injection target line L without transmitting the harmonics of the AC signal S1. That is, the LC series resonance circuit RC2 has a function of linearly amplifying the sine-wave AC signal S1 with respect to the FET2 and 3.

[0152] Also, the primary winding component CP1D also includes a damping resistor R4 that reduces the Q value of the resonance in the LC series resonance circuit RC2. In this case, the capacitor circuit CS and the damping resistor R4 are connected in series with the signal injection winding W2 (or the signal injection winding W3) to form a series circuit, and one end on the capacitor circuit CS side of this series circuit is connected to the output end of the LPF33, and the other end on the damping resistor R4 side of the series circuit (one end of the LC series resonance circuit RC2: one end of the LC resonance circuit) is the high-potential voltage V H and the low-potential voltage V L and the midpoint potential V M(Reference potential). Also, the input terminal of the LPF 33 is connected to the sources of the FETs 2 and 3. Note that the resistance value of the damping resistor R4 is defined as, for example, 1 Ω. However, for this damping resistor R4, instead of a fixed resistor with a fixed resistance value, a variable resistor whose resistance value can be variably adjusted to arbitrarily change the Q value of resonance can also be employed. Also, when it is necessary to increase the Q value of resonance in the LC series resonance circuit RC2, the arrangement of the damping resistor R4 can be omitted.

[0153] Also in this impedance measuring device 1E, in the same manner as in the impedance measuring device 1D, the processing unit 7 controls the on / off states of the four series switches SW11 to SW14 by binary port control to change the capacitance of the entire capacitor circuit CS, and changes the resonance frequency of the LC series resonance circuit RC2 to be the same as or in the vicinity of the frequency of the AC signal S1.

[0154] The signal generation circuit 31A includes the FETs 2 and 3, the resistors R5 and R6, the LPF 33, and the power supply circuits 35 and 36. The FETs 2 and 3 are a push-pull configuration amplifier circuit that amplifies the AC signal S1. The FET 2 is composed of an N-channel MOSFET, and the FET 3 is composed of a P-channel MOSFET. Also, the drain terminal of the FET 2 is connected to the output section of the power supply circuit 35, the source terminal is connected to the source terminal of the FET 3 and the input terminal of the LPF 33 (the other end side of the LC series resonance circuit), and the gate terminal is connected to a signal oscillator (not shown) that generates the AC signal S1. Also, the drain terminal of the FET 3 is connected to the output section of the power supply circuit 36, the source terminal is connected to the source terminal of the FET 2 and the input terminal of the LPF 33, and the gate terminal is connected to a signal oscillator (not shown) that generates the AC signal S1. These FETs 2 and 3 have a positive pulse signal AC signal S1 input to the gate terminal of the FET 2 via the resistor R5 with respect to the midpoint potential V M and a positive pulse signal AC signal S1 input to the gate terminal of the FET 3 via the resistor R6 with respect to the midpoint potential V MA negative pulse signal AC signal S1 is input thereto, and the AC signal S1 is amplified by class D. Note that a bipolar transistor can also be used instead of the FET.

[0155] LPF33 has the same configuration as the LPF33 of the impedance measuring device 1D. The input terminal is connected to the source terminals of FETs 2 and 3, and the output terminal is connected to one end T11 of the capacitor circuit CS (one end of the LC parallel resonance circuit RC1), thereby being connected in series to the LC series resonance circuit RC2. For this reason, when FETs 2 and 3 amplify the AC signal S1 of the pulse signal by class D, LPF33 blocks the passage to the power supply circuits 35 and 36 side and the passage from the power supply circuits 35 and 36 side with respect to the frequency of the harmonic of the AC signal S1. Substantially, together with the LC series resonance circuit RC2, it has a function of linearly amplifying the sine wave AC signal S1 with respect to FETs 2 and 3.

[0156] Power supply circuit 35 is a variable output voltage type power supply device with a voltage V as a potential higher than the midpoint potential V M and generates and outputs a voltage V according to an instruction by the control signal Sc1 output from the processing unit 7. Also, power supply circuit 36 is a variable output voltage type power supply device with a voltage V as a potential lower than the midpoint potential V H and generates and outputs a voltage V according to an instruction by the control signal Sc1 output from the processing unit 7. In this case, power supply circuits 35 and 36 are controlled by the control signal Sc1 output from the processing unit 7 (arithmetic circuit 77) so that the differential voltage obtained by subtracting the midpoint potential V H from the voltage V M is the same as the differential voltage obtained by subtracting the voltage V L from the midpoint potential V L . Also, voltages V H and V M output by power supply circuits 35 and 36 according to an instruction by the control signal Sc1 M are such that the differential voltage obtained by subtracting the midpoint potential V L from the voltage V H is the same as the differential voltage obtained by subtracting the voltage V LBy outputting this, as a result of the drain voltages of FET2 and 3 changing, the voltage (which is also power) of the AC signal S1 output from FET2 and 3 can be freely changed.

[0157] Next, the operation of the impedance measurement device 1E will be described with reference to the accompanying drawings. Note that since the measurement process itself for measuring the internal impedance Zb of the battery Bat as the measurement target is the same as that of the impedance measurement devices 1, 1A, 1B, 1C, and 1D, duplicate explanations will be omitted and different processes will be described.

[0158] In this impedance measurement device 1E, in the impedance calculation process, the processing unit 7 (calculation circuit 77) outputs the control signal Sc1 to the signal generation circuit 31B of the signal injection unit 3 to control the signal level and frequency of the AC signal S1. At this time, the signal generation circuit 31B generates an AC signal S1 of a pulse signal having the frequency indicated by the control signal Sc1 as the fundamental wave and outputs it to FET2 and 3. Also, FET2 and 3 input the AC signal S1 to the gate terminals via the resistors R5 and R6 respectively, and push-pull amplify the AC signal S1 in class D. Further, the power supply circuit 35 controls the voltage value of the voltage V H applied to the drain of FET2 so that the signal level of the AC signal S1 becomes the signal level indicated by the control signal Sc1. At the same time, the power supply circuit 36 controls the voltage value of the voltage V L applied to the drain of FET3 so that the signal level of the AC signal S1 becomes the signal level indicated by the control signal Sc1. Thereby, FET2 and 3 of the signal generation circuit 31B generate and output an AC signal S1 having the signal level and frequency indicated by the control signal Sc1.

[0159] In this case, in a configuration where the LC series resonance circuit RC2 is not provided, when the frequency of the AC signal S1 is high, due to the inductance component of the signal injection winding W2 (or the signal injection winding W3), it becomes difficult for the AC signal S1 to flow through the signal injection winding W2 (or the signal injection winding W3).

[0160] On the other hand, in this impedance measuring device 1E, since it is provided with the LC series resonance circuit RC2, the processing unit 7 (arithmetic circuit 77) outputs the control signal Sc3 to the capacitor circuit CS, so that the four series switches SW11 to SW14 are turned on and off according to the frequency of the AC signal S1 generated by the signal generation circuit 31B, thereby changing the capacitance of the entire capacitor circuit CS. That is, the processing unit 7 (arithmetic circuit 77) changes the resonance frequency of the LC series resonance circuit RC2 to be the frequency of the AC signal S1 or a frequency in the vicinity thereof. In this case, when sweeping the frequency of the AC signal S1, the control signal Sc3 is sequentially output to the capacitor circuit CS so that the resonance frequency is the frequency of the AC signal S1 to be swept or a resonance frequency in the vicinity thereof.

[0161] Therefore, the impedance of the LC series resonance circuit RC2 at the frequency of the AC signal S1 becomes small, and the impedance of the LC series resonance circuit RC2 at the frequency of the harmonic of the AC signal S1 becomes large. As a result, the generation of harmonic distortion of the AC signal S1 in the current path including the LC series resonance circuit RC2 from the sources of the FETs 2 and 3 is suppressed. At the same time, since the impedance of the LPF 33 becomes large at the frequency of the harmonic of the AC signal S1, the generation of harmonic distortion of the AC signal S1 is further suppressed. As a result, the FETs 2 and 3 output a sine-wave AC signal S1. Also, even when the frequency of the AC signal S1 is high, since the inductance component of the signal injection winding W2 (or the signal injection winding W3) is extremely small, the AC signal S1 easily flows through the signal injection winding W2 (or the signal injection winding W3), and as a result, the loss of the AC signal S1 in the LC series resonance circuit RC2 is sufficiently reduced. Further, since the damping resistor R4 reduces the Q value of the resonance in the LC series resonance circuit RC2, the frequency characteristics of the LC series resonance circuit RC2 become broad. As a result, even if there is a slight difference between the frequency of the AC signal S1 generated by the signal generation circuit 31B and the resonance frequency of the LC series resonance circuit RC2, the above effects are sufficiently exhibited. Therefore, the sine-wave AC signal S1 is efficiently injected into the injection target line L as the secondary winding via the signal injection winding W2 (or the signal injection winding W3) as the primary winding.

[0162] In this embodiment, as an example, the capacitors C11 to C14 each have a capacitance of 2 Mb Since the capacitance is set to 0.025μF multiplied by Mb (Mb is an integer between 0 and 4) as a specific capacitance, the capacitance of the capacitor circuit CS as a whole can be finely controlled. On the other hand, since the capacitor circuit CS is configured with four capacitors C11 to C14, the frequency bandwidth of the sweepable AC signal S1 is small. Therefore, by providing a large number of capacitors Cb and the same number of series switches SWb as the number of capacitors, the frequency bandwidth of the sweepable AC signal S1 can be sufficiently increased. In addition, the signal injection winding W3 can be wound around the magnetic core 2 (or the magnetic core 2A), and the processing unit 7 (arithmetic circuit 77) can output a control signal Sc2 to control the parallel switches SW1 to SW4. In this configuration, both the capacitance of the capacitors C11 to C14 of the LC series resonant circuit RC2 and the inductance of the signal injection winding W3 can be changed according to the frequency of the AC signal S1, so that the frequency bandwidth of the sweepable AC signal S1 can be made wider.

[0163] However, in order to change the resonance frequency of the LC series resonance circuit RC2, only the capacitance of the capacitor circuit CS may be changed, or only the inductance of the signal injection winding W3 may be changed using a capacitor with a fixed capacitance without using the capacitor circuit CS, or both the capacitance of the capacitor circuit CS and the inductance of the signal injection winding W3 may be changed. Please confirm. Also, by increasing the number of windings (Na) wound around the magnetic core 2 (or magnetic core 2A) and the number of series switches SWa (Na), the frequency bandwidth of the sweepable AC signal S1 can be further increased. In this case, by changing both the capacitance of the capacitor circuit CS and the inductance of the signal injection winding W3, or by increasing the number of windings (Na) wound around the magnetic core 2 (or magnetic core 2A) and the number of series switches SWa (Na), the resonance frequency can be linearly changed. Also, a BPF (band-pass filter) can be adopted instead of the LPF33. In this configuration, the processing unit 7 (arithmetic circuit 77) adjusts the cut-off frequencies of the low and high bands of the BPF so as to be a frequency band that allows the passage of the AC signal S1. Furthermore, the arrangement of the LPF33 can be omitted. Also, the primary winding component CP1B can be used instead of the primary winding component CP1D. Also, when control of the signal level of the AC signal S1 is not required, the power supply circuits 35, 36 can be configured with voltage-fixed power supply devices.

[0164] As described above, in the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, the signal injection unit 3 injects the AC signal S1 non-contactingly into the core wire of the injection target line L, the non-contact current sensor 5 detects the current value of the injection current Ii flowing through the injection target line L non-contactingly with respect to the core wire of the injection target line L and outputs a detection signal S3 to the processing unit 7, the voltage detection unit 6 detects the voltage value of the AC signal S1 generated across both ends of the battery Bat by contacting both ends thereof and outputs a both-end voltage signal S4 to the processing unit 7, and the processing unit 7 (arithmetic circuit 77) inputs the detection signal S3 and the both-end voltage signal S4 and measures the internal impedance Zb (or internal impedance Zc) of the battery Bat (or battery cell Cel) based on the detection signal S3 and the both-end voltage signal S4.

[0165] Therefore, according to the impedance measuring apparatuses 1, 1A, 1B, 1C, 1D, and 1E, even when a high voltage exists in the injection target line L to which the battery Bat is connected in series and the measurement AC signal S1 is injected, since the signal injection unit 3 injects the AC signal S1 in a non-contact manner with respect to the core wire of the injection target line L, as a result, components with a low withstand voltage specification can be used as components constituting the signal injection unit 3, and thus the manufacturing cost of the signal injection unit 3 can be reduced, and further the manufacturing cost of the entire impedance measuring apparatuses 1, 1A, 1B, 1C, 1D, and 1E can be sufficiently reduced, and the internal impedance Zb (or internal impedance Zc) of the battery Bat (or battery cell Cel) as the measurement target can be surely measured.

[0166] Further, according to the impedance measuring apparatuses 1, 1A, 1B, 1C, 1D, and 1E, when the processing unit 7 measures the internal impedance Zb (or internal impedance Zc) of the battery Bat (or battery cell Cel) which is the measurement target connected in series to the injection target line, when an AC signal S1 is injected into the injection target line L, based on the current value of the AC signal S1 flowing through the injection target line L (the current value of the injection current Ii: detection signal S3) and the voltage value generated at both ends of the battery Bat (both-end voltage signal S4), by measuring the internal impedance Zb (or internal impedance Zc) of the battery Bat (or battery cell Cel), a magnetic flux Mc can be more surely generated in the magnetic core 2, and the AC signal S1 can be more surely and efficiently injected into the injection target line L. As a result, the internal impedance Zb (or internal impedance Zc) of the battery Bat (or battery cell Cel) can be measured with high accuracy.

[0167] Also, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, the non-contact current sensor 5 non-contactly detects the injection current Ii (current of an alternating current) flowing through the injection target line L and outputs a detection signal S3 to the processing unit 7, and the voltage detection unit 6 outputs the both-end voltage signal S4 detected by contacting both ends of the battery Bat to be measured to the processing unit 7 in a state of being insulated from the battery Bat. Thus, even if the output voltage of the battery Bat is a very high voltage, and also even if there is noise such as switching noise around the load Load and the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, it is possible to accurately detect a minute alternating voltage generated in the battery Bat when the injection current Ii flows through the battery Bat. Therefore, according to this impedance measuring device 1, 1A, 1B, 1C, 1D, 1E, the internal impedance Zb (or internal impedance Zc) of the battery Bat (or battery cell Cel) can be accurately measured. Also, according to this impedance measuring device 1, 1A, 1B, 1C, 1D, 1E, by using the non-contact current sensor 5, it is possible to measure the internal impedance Zb (or internal impedance Zc) of the battery Bat (or battery cell Cel) non-contactly without cutting the injection target line L.

[0168] Also, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, the arithmetic circuit 77 of the processing unit 7 (or 7A) calculates the internal impedance Zb (or internal impedance Zc) of the battery Bat (or battery cell Cel) to be measured based on the in-phase component and quadrature component of the injection current Ii (detection signal S3) as an alternating current output from the quadrature detection circuit 75 and the in-phase component and quadrature component of the both-end voltage signal S4 as an alternating voltage output from the quadrature detection circuit 76. Thus, even when the signal level of the alternating signal S1 injected into the injection target line L is small, it is possible to increase the ratio (S / N) of the signal level (S) to the noise level (N) and accurately measure the internal impedance Zb (or internal impedance Zc).

[0169] Also, in impedance measuring devices 1, 1A, 1B, 1C, 1D, and 1E, the signal injection unit 3 includes primary winding component parts CP that constitute a primary winding magnetically coupled to an injection target line L as a secondary winding, and applies an AC signal S1 to both ends of the primary winding component parts CP to inject the AC signal S1 into the injection target line L. Further, in impedance measuring devices 1, 1A, 1B, 1C, 1D, and 1E, the primary winding component parts CP are configured by winding an insulated covered wire around an annular magnetic core 2 through which the injection target line L is inserted. Therefore, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, and 1E, the primary winding component parts CP can be simply configured and the AC signal S1 can be reliably injected into the injection target line L.

[0170] Also, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, and 1E, by providing a gap G in the magnetic cores 2, 2A, magnetic saturation of the magnetic core 2 can be avoided.

[0171] Further, in impedance measuring devices 1, 1A, 1B, 1C, 1D, and 1E, the magnetic core 2 (or magnetic core 2A) is composed of a plurality of C-shaped unit magnetic cores UC, and the plurality of unit magnetic cores UC are stacked such that the separation distances of two gaps G adjacent to each other along the outer periphery of the magnetic core 2 (or magnetic core 2A) are equal in a top view of the stacked state. Therefore, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, and 1E, even if the injection target line L inserted into the magnetic core 2 (or magnetic core 2A) is located at a position close to the gap G, the AC signal S1 can be stably injected into the injection target line L without reducing the injection of the AC signal S1 into the injection target line L regardless of the position.

[0172] Also, in impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, the primary winding component CP includes four windings from the first winding Wd1 to the fourth winding Wd4 (4 is an example of Na), and four parallel switches from the first parallel switch SW1 to the fourth parallel switch SW4 (4 is an example of Na) that are respectively connected in parallel to the first winding Wd1 to the fourth winding Wd4. The first winding Wd1 to the fourth winding Wd4 are wound such that the number of turns is different for each. Therefore, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, by changing the total number of turns of the primary winding component CP, regardless of the magnitude of the load impedance as seen from the signal injection winding W3 when the load Load is connected to the battery Bat and in a closed loop state, the AC signal S1 can be accurately injected into the injection target line L. Also, according to the impedance measuring devices 1A, 1B, 1C, 1D, 1E, the increase or decrease in the number of turns can be made larger compared to the primary winding component CP (signal injection winding W2) configured with the same number of turns.

[0173] Furthermore, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, the first winding Wd1 to the fourth winding Wd4 (example where Na is 4) are wound with the number of turns multiplied by 10 (example where La is 10) for each of 1, 2, 4, and 8 (example where Ma is each integer from 0 to 3), so that the total number of turns of the primary winding component CP can be finely controlled. Ma Also, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, since the core wire diameter of the insulated covered wire of the winding Wd with a larger number of turns is formed thinner than the core wire diameter of the insulated covered wire of the winding Wd with a smaller number of turns among the first winding Wd1 to the fourth winding Wd4, as a result, a thin insulated covered wire (or enameled wire) can be used for the winding Wd with a larger number of turns, and thus the productivity of the signal injection winding W3 can be sufficiently improved.

[0174] Also, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, since the core wire diameter of the insulated covered wire of the winding Wd with a larger number of turns is formed thinner than the core wire diameter of the insulated covered wire of the winding Wd with a smaller number of turns among the first winding Wd1 to the fourth winding Wd4, as a result, a thin insulated covered wire (or enameled wire) can be used for the winding Wd with a larger number of turns, and thus the productivity of the signal injection winding W3 can be sufficiently improved.

[0175] Further, according to the impedance measuring devices 1D and 1E, since the signal injection unit 3 includes a capacitor circuit CS that forms an LC resonance circuit (LC parallel resonance circuit RC1 or LC series resonance circuit RC2) having a resonance point at the frequency of the AC signal S1 or a frequency near that frequency, together with the signal injection winding W2 (or signal injection winding W3), as a result, the AC signal S1 easily flows through the signal injection winding W2 (or signal injection winding W3), and thus, the loss of the AC signal S1 in the LC resonance circuit (LC parallel resonance circuit RC1 or LC series resonance circuit RC2) can be sufficiently reduced.

[0176] Further, according to the impedance measuring devices 1D and 1E, since the signal injection unit 3 includes a damping resistor R1 (or damping resistor R4) that reduces the Q value of the LC resonance circuit (LC parallel resonance circuit RC1 or LC series resonance circuit RC2), even if there is a slight difference between the frequency of the AC signal S1 generated by the signal generation circuit 31A and the resonance frequency of the LC resonance circuit (LC parallel resonance circuit RC1 or LC series resonance circuit RC2), the loss of the AC signal S1 in the LC resonance circuit (LC parallel resonance circuit RC1 or LC series resonance circuit RC2) can be sufficiently reduced.

[0177] Further, according to the impedance measuring devices 1D and 1E, the signal injection unit 3 includes an amplifier circuit (FET1 or FET2, 3) that amplifies the AC signal S1, and since the LC resonance circuit (LC parallel resonance circuit RC1 or LC series resonance circuit RC2) is arranged as the load circuit of the amplifier circuit (FET1 or FET2, 3), the amplifier circuit (FET1 or FET2, 3) can linearly amplify the sinusoidal AC signal S1.

[0178] Further, according to the impedance measuring device 1D, one end of the LC parallel resonance circuit RC1 has a high potential voltage V HConnected thereto, the amplifier circuit is composed of an N-channel MOSFET (FET1). The other end side of the LC parallel resonance circuit RC1 is connected to the drain terminal, the source terminal is connected to the reference potential, and a pulse signal as an AC signal S1 is input to the gate terminal to perform class-D amplification of the AC signal S1, whereby the amplifier circuit (FET1) can be simply configured.

[0179] Also, according to the impedance measuring device 1D, since the voltage V of the high potential is configured to be variable, as a result of the change in the drain voltage of FET1, the voltage (which is also power) of the AC signal S1 output from FET1 can be freely changed. H As a result of the drain voltage of FET1 changing, the voltage (which is also power) of the AC signal S1 output from FET1 can be freely changed.

[0180] Also, according to the impedance measuring device 1E, one end of the LC series resonance circuit RC2 is connected to the reference potential, and the amplifier circuit is configured as a push-pull circuit by an N-channel MOSFET (FET2) and a P-channel MOSFET (FET3). The drain terminal of FET2 is connected to a voltage V that is higher than the midpoint potential V M (reference potential), the drain terminal of FET3 is connected to a voltage V that is lower than the midpoint potential V H (reference potential), the other end side (LPF33 side) of the LC series resonance circuit RC2 is connected to the source terminals of FET2 and FET3, and a positive pulse signal as the AC signal S1 is input to the gate terminal of FET2 and a negative pulse signal as the AC signal S1 is input to the gate terminal of FET3 to perform class-D amplification of the AC signal S1, whereby the AC signal S1 can be reliably class-D amplified by the amplifier circuit (FET2, 3) configured as a push-pull circuit. M (reference potential), and the other end side (LPF33 side) of the LC series resonance circuit RC2 is connected to the source terminals of FET2 and FET3. When a positive pulse signal as the AC signal S1 is input to the gate terminal of FET2 and a negative pulse signal as the AC signal S1 is input to the gate terminal of FET3 to perform class-D amplification of the AC signal S1, the AC signal S1 can be reliably class-D amplified by the amplifier circuit (FET2, 3) configured as a push-pull circuit. L (reference potential), and the other end side (LPF33 side) of the LC series resonance circuit RC2 is connected to the source terminals of FET2 and FET3. When a positive pulse signal as the AC signal S1 is input to the gate terminal of FET2 and a negative pulse signal as the AC signal S1 is input to the gate terminal of FET3 to perform class-D amplification of the AC signal S1, the AC signal S1 can be reliably class-D amplified by the amplifier circuit (FET2, 3) configured as a push-pull circuit.

[0181] Also, according to the impedance measuring device 1E, since the high potential voltage V H and the low potential voltage V L are each configured to be variable, as a result of the change in the drain voltages of FET2 and FET3, the voltage (which is also power) of the AC signal S1 output from FET2 and FET3 can be freely changed.

[0182] Further, according to the impedance measuring devices 1D and 1E, by including either a LPF 33 or a BPF connected in series to an LC resonance circuit (LC parallel resonance circuit RC1 or LC series resonance circuit RC2) and allowing the passage of the AC signal S1, the amplifier circuit (FET1 or FET2, 3) can surely and linearly amplify the sinusoidal AC signal S1.

[0183] Further, according to the impedance measuring devices 1D and 1E, the capacitor circuit CS is composed of four capacitors from the first capacitor (capacitor C11) to the fourth capacitor (capacitor 14: example where Nb is 4) connected in parallel as a whole, and four switches from the first series switch (switch SW1) to the fourth series switch (switch SW4) connected in series to the first capacitor (capacitor C11) to the fourth capacitor respectively. The processing unit 7 (arithmetic circuit 77) can finely control the resonance frequency of the LC resonance circuit (LC parallel resonance circuit RC1 or LC series resonance circuit RC2) by turning on and off the four series switches SWb according to the frequency of the AC signal S1 and changing the capacitance of the capacitor circuit CS as a whole.

[0184] Further, according to the impedance measuring devices 1D and 1E, since the capacitances of the first capacitor (capacitor C11) to the fourth capacitor are different from each other, the increase and decrease of the capacitance can be made larger compared to the capacitor circuit CS composed of capacitors of the same capacitance.

[0185] Further, according to the impedance measuring devices 1D and 1E, the first capacitor (capacitor C11) to the fourth capacitor (capacitor 14: example where Nb is 4) are each 2 Mb (Mb is four integers from 0 to (Nb - 1: 3)) and has a capacitance obtained by multiplying a specific capacitance (in this example, "0.025 μF"), so the capacitance of the capacitor circuit CS as a whole can be changed, and thus the resonance frequency of the LC resonance circuit (LC parallel resonance circuit RC1 or LC series resonance circuit RC2) can be finely controlled.

[0186] Also, in the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, the processing unit 7 (arithmetic circuit 77) controls the signal level of the alternating current signal S1 output from the signal injection unit 3 so that the current value of the injection current Ii (alternating current signal S1) detected by the non-contact current sensor 5 is included within the target current value range. Also, in the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, the processing unit 7 (arithmetic circuit 77) controls the on / off states of the first parallel switch SW1 to the fourth parallel switch SW4 so that the current value of the injection current Ii (alternating current signal S1) detected by the non-contact current sensor 5 is included within the target current value range. Also, in the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, the processing unit 7 (arithmetic circuit 77) discriminates the load impedance of the injection target line L based on the current value (alternating current Iac) of the alternating current signal S1 injected by the signal injection unit 3 into the injection target line L and the current value (injection current Ii) of the alternating current signal S1 detected by the non-contact current sensor 5, and controls the on / off states of the first parallel switch SW1 to the fourth parallel switch SW4. As a result, when the discriminated load impedance is small, the number of turns of the primary winding component CP as a whole is increased, and when the discriminated load impedance is large, the number of turns of the primary winding component CP as a whole is decreased. Therefore, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, the ratio (S / N) of the signal level (S) to the noise level (N) of the detection signal S3 and the both-end voltage signal S4 can be increased. As a result, in the arithmetic processing (measurement processing) of the internal impedance Zb (or internal impedance Zc) performed by the processing unit 7 (arithmetic circuit 77), the internal impedance Zb (or internal impedance Zc) can be accurately measured.

[0187] Further, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, since the non-contact current sensor 5 as the signal detection unit is formed separately from the signal injection unit 3 and includes the secondary winding component CP2, it is possible to avoid leakage magnetic flux corresponding to the alternating current signal S1 injected by the signal injection winding W2 of the signal injection unit 3 from leaking out as noise to the secondary winding component CP2. Therefore, the internal impedance Zb (or the internal impedance Zc) can be accurately measured. In this case, as the signal detection unit, a configuration in which a secondary winding component forming a primary winding magnetically coupled to the injection target line L as the secondary winding is wound around the magnetic core 2 (2A) can be adopted separately and independently from the non-contact current sensor 5. However, in this configuration, since the leakage magnetic flux corresponding to the alternating current signal S1 injected by the signal injection winding W2 of the signal injection unit 3 leaks out as noise to the secondary winding component, it is preferable to configure the signal detection unit separately from the signal injection unit 3.

[0188] Further, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, the non-contact current sensor 5 (signal detection unit) combines the detection function of the alternating current Iac for measuring the internal impedance Zb (configuration of the current detection unit) and the control function for the current value of the alternating current Iac (configuration of the signal detection unit), so that the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E can be miniaturized and the manufacturing cost can be sufficiently reduced.

[0189] Further, according to the impedance measuring devices 1B, 1C, the frequency band of the alternating current signal S1 is grouped, and by using the magnetic core 2 (or the magnetic core 2A) or the air-core coil AC as the primary winding component CP according to each frequency band group F, when injecting the alternating current signal S1 into the injection target line L in a transformer manner, since the magnetic core 2 (or the magnetic core 2A) or the air-core coil AC made of a material most suitable for coupling with the injection target line L according to the frequency of the alternating current signal S1 can be used, the alternating current signal S1 can be injected into the injection target line L sufficiently efficiently over a wide frequency band.

[0190] Also, according to the impedance measuring devices 1B and 1C, when the signal injection unit 3 changes the frequency of the AC signal S1 from one frequency band group F to the other frequency band group F at the boundary FLM (or boundary FMH) between two frequency band groups F whose frequency bands of the AC signal S1 are adjacent to each other, by applying the AC signal S1 to the two primary winding component parts CP corresponding to the two adjacent frequency band groups F, at the boundary FLM (or boundary FMH), since the magnetic cores 2 (or magnetic cores 2A) of two types of materials with suitable coupling to the injection target line L according to the frequency of the AC signal S1 are used, the AC signal S1 can be injected into the injection target line L sufficiently efficiently. Also, according to the impedance measuring devices 1B and 1C, when changing the frequency of the AC signal S1 from one frequency band group F to the other frequency band group F at the boundary FLM (or boundary FMH) between two frequency band groups F whose frequency bands of the AC signal S1 are adjacent to each other, it is possible to gently reduce the fluctuation of the signal level of the AC signal S1 caused by the switching of the primary winding component part CP to which the AC signal S1 is applied.

[0191] Also, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, and 1E, by configuring the primary winding component part CP1B with the air-core coil AC, it is possible to surely inject the AC signal S1 in the high-frequency band into the injection target line L while having a simple configuration.

[0192] Also, according to the impedance measuring devices 1B and 1C, the signal injection unit 3 (signal generation circuit 31) includes a plurality (two in the above example) of primary winding component parts CP of the same specification, and by simultaneously applying a plurality (two in the above example) of AC signals S1 having the same frequency and in the same phase to the plurality of primary winding component parts CP, compared with using one primary winding component part CP, an injection current Ii with a sufficiently large current value can be injected into the injection target line L.

[0193] Further, according to the impedance measuring device 1C, a plurality of voltage detection units 6 are provided, and the plurality of voltage detection units 6 detect the voltage values of the AC signals S1 generated at both ends of each battery cell Cel as a plurality of measurement targets connected in series to the injection target line L, and output both-end voltage signals S4 to the processing unit 7 respectively. The processing unit 7 (arithmetic circuit 77) measures the internal impedance Zc of each battery cell Cel based on the detection signal S3 and the plurality of both-end voltage signals S4, so that the internal impedance Zb and the internal impedance Zc of the plurality of measurement targets (battery Bat and Cel) can be measured simultaneously.

[0194] Further, according to the impedance measuring devices 1A, 1B, 1C, 1D, 1E, by providing a capacitor connected in parallel to both ends of the load Load in the measurement system in which the battery Bat as the measurement target and the load Load as the non-measurement target are connected by the injection target line L to form an annular closed loop, even if the impedance of the load Load is large, the current value of the AC current Iac at the time of injecting the AC signal S1 into the injection target line L by the signal injection unit 3 can be increased.

[0195] Further, according to the impedance measuring devices 1A, 1B, 1C, by configuring the signal injection unit 3 with a class-D amplifier unit as the final stage, the signal injection unit 3 can maintain the output level of the AC signal S1 at a constant level controlled against load fluctuations.

[0196] Further, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, 1E, by sweeping the frequency of the AC signal S1 with respect to the signal generation circuit 31 in the signal injection unit 3, the AC signal S1 which is a sine wave signal can be supplied to the battery Bat or the like, and it can be configured as an FRA capable of measuring the frequency response, so that high-precision impedance measurement can be performed.

[0197] Further, according to the impedance measuring devices 1, 1A, 1B, 1C, 1D, and 1E, as the metal magnetic core, by using any one of a permalloy core, a sendust core, an amorphous core, a dust core, pure iron, silicon steel sheet, permendur, nickel, cobalt, Fe-Si-Al, and electromagnetic stainless steel, a magnetic core 2 (magnetic core 2A) that is difficult to be magnetically saturated with respect to a direct current can be configured. As the ferrite magnetic core, by using any one of an Mn-Zn ferrite and an Ni-Zn ferrite, the generation of eddy currents in the magnetic core 2 (magnetic core 2A) can be avoided.

[0198] Note that the signal injection device 10 is not limited to being applied to the impedance measuring device, and can be applied to various measuring instruments that inject and measure an alternating current signal S1 into the injection target line L. Further, the impedance measuring device can measure the impedances of various measurement targets, not limited to measuring the internal impedance Zb of the battery Bat or the internal impedance Zc of the battery cell Cel. For example, taking a water electrolysis cell that electrolyzes water to produce hydrogen as a measurement target, in a closed loop in which the water electrolysis cell and a power source for the water electrolysis cell instead of the load Load are connected by the injection target line L, probes P1 and P2 are connected to the anode and cathode of the water electrolysis cell to measure the internal impedance of the water electrolysis cell. In this case, the internal impedances of the respective water electrolysis cells in a state where a plurality of water electrolysis cells are connected in series can also be measured simultaneously using the impedance measuring device 1C.

[0199] Also, in the impedance measuring device 1, the winding W1 and the winding W2 can be wound around separate magnetic cores 2.

[0200] Also, the configuration of the signal generation circuit 31A in the impedance measuring device 1D and the configuration of the signal generation circuit 31B in the impedance measuring device 1E can be applied to the configuration of the signal generation circuit 31 of the impedance measuring devices 1, 1A, 1B, and 1C.

[0201] Also, an example of the impedance measurement devices 1, 1A, 1B, 1C using the non-contact current sensor 5 as a current sensor for detecting the current value of the injection current Ii has been described. However, the configuration is not limited to non-contact type, and a configuration in which a current transformer, a current detection resistor, etc. are arranged in the injection target line L to detect the current value of the injection current Ii can be adopted.

[0202] Furthermore, when it is not necessary to insulate the reference potential (floating ground) of the impedance measurement devices 1, 1A, 1B, 1C, 1D, 1E, the arrangement of the insulation circuit 62 can be omitted, and the reference potential (ground) and the reference potential (floating ground) of the impedance measurement devices 1, 1A, 1B, 1C, 1D, 1E can be set to the same potential. Also, the A / D conversion circuits 71, 72, 73 can be provided in the signal generation circuit 31, the non-contact current sensor 5, and the voltage detection unit 6, respectively. Also, an example in which the 2f signal generation circuit 31a and the 1 / 2 frequency division circuit 31b are configured as the signal generation circuit 31 has been described, but a configuration in which the 2f signal generation circuit 31a and the 1 / 2 frequency division circuit 31b are provided separately and independently from the signal generation circuit 31 can also be adopted.

[0203] Also, in the impedance measurement devices 1, 1A, 1B, 1C, 1D, 1E, an example in which the impedance such as the internal impedance Zb (or internal impedance Zc) of the battery Bat is calculated by digital processing has been described. However, a configuration in which the impedance is obtained by analog calculation using an analog circuit based on the AC signal S1, the detection signal S3, and the both-end voltage signal S4 can also be adopted.

Industrial Applicability

[0204] According to the present invention, as a result of being able to use components with a low withstand voltage specification as components constituting the signal injection unit, the manufacturing cost of the signal injection unit can be sufficiently reduced, and thus the manufacturing cost of the entire impedance measurement device can be sufficiently reduced, and the impedance of the measurement target can be reliably measured. Thereby, the present invention can be widely applied to such impedance measurement devices for impedance measurement.

Description of Symbols

[0205] 1,1A~1E Impedance Measuring Device 2,2A Magnetic Core 3,3A Signal Injection Section 31,31A,31B Signal Generation Circuit 33 Low-Pass Filter 34~36 Power Supply Circuit 4,4A~4D Magnetic Flux Cancellation Section 41 Hall Element 42 Voltage Driver 43,48 LPF 44 Addition Circuit 45 Current Driver 47 Synchronous Detection Circuit 5 Non-Contact Current Sensor 6,6-1,6-2,6-3 Voltage Detection Section 61 Buffer Circuit 62 Isolation Circuit 7,7A Processing Section 74 Phase-Shifting Circuit 75,76,76-1,76-2,76-3 Quadrature Detection Circuit 77 Arithmetic Circuit 10 Signal Injection Device AC Air Core Coil Bat Battery C11~C14 Capacitor Cel1~Cel3 Battery Cell CP1,CP1A,CP1B,CP1C,CP1D Primary Winding Component CP2 Secondary Winding Component CS Capacitor Circuit FL,FM,FH Frequency Band Group FLM,FMH Boundary Section G Gap Ii Injection Current Load Load R1,R4 Damping Resistor RC1 LC Parallel Resonance Circuit RC2 LC Series Resonance Circuit S1 AC Signal S2 Voltage Signal S3 detection signal S4 both - end voltage signal Sd output signal Sdc DC signal Sr reference signal SW1~SW4 parallel switches SW11~SW14 series switches UC unit magnetic core W1 flux - cancellation winding W2, W3 signal - injection windings Wd1~Wd4 windings Zb internal impedance Zc internal impedance

Claims

1. A signal injection unit that generates an alternating current signal for measurement and injects the alternating current signal into an injection target line to which a measurement target is connected in series, A non-contact current detection unit that non-contact detects a current value of the alternating current signal flowing through the injection target line and outputs a current detection signal, A voltage detection unit that contacts both ends of the measurement target to detect a voltage value of an alternating voltage generated at both ends and outputs a voltage detection signal, An impedance measurement device comprising a processing unit that inputs the current detection signal and the voltage detection signal and measures the impedance of the measurement target based on the current detection signal and the voltage detection signal, The signal injection unit is an impedance measurement device configured to be able to inject the alternating current signal into the injection target line in a non-contact manner.

2. The impedance measurement device according to claim 1, wherein the voltage detection unit includes an insulation circuit that outputs the detected voltage detection signal to the processing unit in a state of being insulated from the measurement target.

3. The processing unit includes a first quadrature detection circuit that inputs the alternating current signal and quadrature-detects the current detection signal to generate an in-phase component and a quadrature component of the alternating current, and a second quadrature detection circuit that inputs the alternating current signal and quadrature-detects the voltage detection signal to generate an in-phase component and a quadrature component of the alternating voltage, The impedance measurement device according to claim 1 or 2, further comprising an arithmetic circuit that calculates the impedance of the measurement target based on the in-phase component and the quadrature component of the alternating current output from the first quadrature detection circuit and the in-phase component and the quadrature component of the alternating voltage output from the second quadrature detection circuit.

4. The impedance measurement device according to any one of claims 1 to 3, wherein the signal injection unit includes a primary winding component that constitutes a primary winding magnetically coupled to the injection target line as a secondary winding, and injects the alternating current signal into the injection target line by applying the alternating current signal to the primary winding component.

5. The impedance measurement device according to claim 4, wherein the primary winding component includes an insulated wire wound around a circular first magnetic core through which the injection target line is inserted.

6. The impedance measurement device according to claim 5, wherein the first magnetic core is provided with a gap.

7. The first magnetic core is composed of a plurality of C-shaped unit magnetic cores, The impedance measuring device according to claim 6, wherein in a top view of the plurality of unit magnetic cores in a stacked state, the separation distances of two adjacent gaps along the outer periphery of the first magnetic core are equal.

8. The primary winding component includes Na windings from the first winding to the Na-th winding (Na is an integer of 2 or more) that are formed of the insulated coated wire wound around the first magnetic core and are connected in series as a whole, and the first parallel switch to the Na-th parallel switch that are respectively connected in parallel to the first winding to the Na-th winding. The impedance measuring device according to any one of claims 5 to 7, wherein the processing unit controls the on / off of the Na parallel switches to change the number of turns of the primary winding component as a whole. The impedance measuring device according to any one of claims 5 to 7, wherein the processing unit controls the on / off of the Na parallel switches to change the number of turns of the primary winding component as a whole.

9. The impedance measuring device according to claim 8, wherein the first winding to the Na-th winding are respectively wound such that their numbers of turns are different from each other.

10. From the first winding wire to the Nath winding wire, each is wound by a number obtained by multiplying by an integer La of 1 or more at 2 Ｍａ (Ma is Na integers from 0 to (Na - 1)) The impedance measuring device according to claim 9, which is wound by a number obtained by multiplying by an integer La of 1 or more.

11. The impedance measuring device according to claim 9 or 10, wherein the first winding to the Na-th winding are formed such that the wire diameter of the core wire in the insulated coated wire of the winding with a larger number of turns is thinner than the wire diameter of the core wire in the insulated coated wire of the winding with a smaller number of turns.

12. The impedance measuring device according to any one of claims 5 to 11, wherein the signal injection unit includes a capacitor circuit that forms an LC resonance circuit having a resonance point at the frequency of the AC signal or a frequency near the frequency together with the primary winding.

13. The impedance measuring device according to claim 12, wherein the signal injection unit includes a damping resistor that reduces the Q value of the LC resonance circuit.

14. The signal injection unit includes an amplifier circuit that amplifies the AC signal. The impedance measuring device according to claim 12 or 13, wherein the LC resonance circuit is arranged as a load circuit of the amplifier circuit.

15. The LC resonance circuit is configured as an LC parallel resonance circuit with one end thereof connected to a high potential. The impedance measuring device according to claim 14, wherein the amplifier circuit is composed of an N-channel MOSFET, the other end side of the LC resonance circuit is connected to the drain terminal, the source terminal is connected to a low potential, and a pulse signal as the AC signal is input to the gate terminal to perform class-D amplification of the AC signal.

16. The impedance measuring device according to claim 15, wherein the voltage of the high potential is configured to be variable.

17. One end of the LC resonance circuit is connected to a reference potential and is configured as an LC series resonance circuit. The amplifier circuit is configured as a push-pull circuit by an N-channel MOSFET and a P-channel MOSFET. The drain terminal of the N-channel MOSFET is connected to a potential higher than the reference potential, and the drain terminal of the P-channel MOSFET is connected to a potential lower than the reference potential. The other end side of the LC series resonance circuit is connected to the source terminals of the N-channel MOSFET and the P-channel MOSFET, and a positive pulse signal as the AC signal is input to the gate terminal of the N-channel MOSFET, and a negative pulse signal as the AC signal is input to the gate terminal of the P-channel MOSFET to perform class-D amplification of the AC signal. The impedance measuring device according to claim 14.

18. The impedance measuring device according to claim 17, wherein the voltage of the high potential and the voltage of the low potential are each configured to be variable.

19. The impedance measuring device according to any one of claims 12 to 18, further comprising either an LPF or a BPF connected in series to the LC resonance circuit to allow passage of the AC signal.

20. The capacitor circuit includes Nb capacitors from a first capacitor to an Nb-th capacitor (Nb is an integer of 2 or more) connected in parallel as a whole, and Nb switches from a first series switch to an Nb-th series switch each connected in series to the first capacitor to the Nb-th capacitor. The processing unit controls on / off of the Nb series switches according to the frequency of the AC signal to change the capacitance of the capacitor circuit as a whole. The impedance measuring device according to any one of claims 12 to 19.

21. The impedance measuring device according to claim 20, wherein the first capacitor to the Nb-th capacitor have different capacitances from each other.

22. From the first capacitor to the Nb-th capacitor, each has a capacitance obtained by multiplying a specific capacitance by 2 Ｍｂ The impedance measuring device according to claim 21, wherein the capacitances of the first capacitor to the Nb-th capacitor each have a capacitance obtained by multiplying a specific capacitance by 2 (where Mb is Nb integers from 0 to (Nb - 1)).

23. The signal injection unit includes a plurality of the primary winding components respectively corresponding to frequency band groups obtained by grouping the frequency bands of the generated AC signals. When injecting the AC signal having a frequency belonging to one of the frequency band groups, the AC signal is applied to both ends of the primary winding component corresponding to the one frequency band group. The impedance measuring device according to any one of claims 5 to 22, wherein the frequency band is grouped into two frequency band groups, and the first magnetic core in the primary winding component corresponding to the frequency band group on the low-frequency band side of the two frequency band groups is composed of a metal magnetic core, and the first magnetic core in the primary winding component corresponding to the frequency band group on the high-frequency band side of the two frequency band groups is composed of a ferrite magnetic core.

24. The signal injection unit includes a plurality of the primary winding components respectively corresponding to frequency band groups obtained by grouping the frequency bands of the generated AC signals. When injecting the AC signal having a frequency belonging to one of the frequency band groups, the AC signal is applied to both ends of the primary winding component corresponding to the one frequency band group. The impedance measuring device according to any one of claims 5 to 22, wherein the frequency band is grouped into three frequency band groups, the first magnetic core in the primary winding component corresponding to the frequency band group on the low-frequency band side of the three frequency band groups is composed of a metal magnetic core, the first magnetic core in the primary winding component corresponding to the frequency band group on the middle-frequency band side of the three frequency band groups is composed of a ferrite magnetic core, and the primary winding component corresponding to the frequency band group on the high-frequency band side of the three frequency band groups is composed of an air-core coil.

25. The signal injection unit is configured to be able to change the frequency of the AC signal, and when changing the frequency of the AC signal from one of the frequency band groups to the other at the boundary of two frequency band groups whose frequency bands of the AC signal are adjacent to each other, the AC signal is applied to the two primary winding component parts corresponding to the two adjacent frequency band groups. The impedance measuring device according to claim 23 or 24.

26. Comprising a signal detection unit that detects the current value of the AC signal flowing through the injection target line, The processing unit controls the signal level of the AC signal output from the signal injection unit so that the current value of the AC signal detected by the signal detection unit is included within a target current value range. The impedance measuring device according to any one of claims 1 to 25.

27. Comprising a signal detection unit that detects the current value of the AC signal flowing through the injection target line, The processing unit controls the on / off of the first parallel switch to the Na parallel switch so that the current value of the AC signal detected by the signal detection unit is included within a target current value range. The impedance measuring device according to any one of claims 8 to 11.

28. Comprising a signal detection unit that detects the current value of the AC signal flowing through the injection target line, The processing unit discriminates the load impedance of the injection target line based on the current value of the AC signal injected by the signal injection unit into the injection target line and the current value of the AC signal detected by the signal detection unit, and controls the on / off of the first parallel switch to the Na parallel switch. When the discriminated load impedance is small, the number of turns of the entire primary winding component is increased, and when the discriminated load impedance is large, the number of turns of the entire primary winding component is decreased. The impedance measuring device according to any one of claims 8 to 11.

29. The signal detection unit is formed separately from the signal injection unit and includes a secondary winding component that forms a secondary winding magnetically coupled to the injection target line as a primary winding. The impedance measuring device according to any one of claims 26 to 28.

30. The signal detection unit functions as the current detection unit. The impedance measuring device according to any one of claims 26 to 29.

31. The impedance measuring device according to claim 4, wherein the primary winding component is composed of an air-core coil.

32. The impedance measuring device according to any one of claims 4 to 31, wherein the signal injection unit includes a plurality of primary winding components of the same specification, and applies the AC signals of the same frequency and in the same phase to the plurality of primary winding components of the same specification simultaneously.

33. The impedance measuring device includes a plurality of voltage detection units, the plurality of voltage detection units detect voltage values of AC voltages generated at both ends of each of the plurality of measurement objects connected in series to the injection target line by contacting both ends thereof, and output the voltage detection signals to the processing unit respectively, the processing unit measures the impedance of each of the plurality of measurement objects based on the current detection signal and the plurality of voltage detection signals respectively output from the plurality of voltage detection units. The impedance measuring device according to any one of claims 1 to 32.

34. The impedance measuring device according to any one of claims 1 to 33, further comprising a capacitor connected in parallel to both ends of the non-measurement object in a measurement system in which the measurement object and the non-measurement object are connected by the injection target line to form an annular closed loop.

35. The impedance measuring device according to any one of claims 1 to 11 and 23 to 34, wherein the signal injection unit includes a class-D amplifier as a final stage, and injects the AC signal amplified by the class-D amplifier into the injection target line.

36. The impedance measuring device according to any one of claims 1 to 35, wherein the signal injection unit sweeps the frequency of the AC signal.

37. The metal magnetic core is any one of permalloy core, sendust core, amorphous core, powder core, pure iron, silicon steel sheet, permendur, nickel, cobalt, Fe-Si-Al and electromagnetic stainless steel, and the ferrite magnetic core is any one of Mn-Zn ferrite and Ni-Zn ferrite. The impedance measuring device according to claim 23 or 24.

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