Power converter, control method for the inverter of the power converter, and control program

Abstract

This invention provides a power conversion device that controls an inverter circuit in response to changes in the control amount of a rectifier. [Solution] The present invention relates to a power conversion device that transmits power from a power supply coil 11 to a power output coil 21 in a non-contact manner, thereby outputting power through a rectifier 23. The power conversion device comprises an inverter circuit 13 electrically connected to the power supply coil 11, a power supply 46 electrically connected to the inverter circuit 13, a PWM control unit 34 electrically connected to the inverter circuit 13, and an A / D conversion circuit 31 electrically connected to the PWM control unit 34. The A / D conversion circuit 31 measures the inverter current Iinv output from the inverter circuit 13 from the power supply resonant circuit 12 at a predetermined time, reflecting the change in the control amount of the rectifier 23. The PWM control unit 34 generates a gate signal for the inverter circuit 13 based on the difference between the inverter current Iinv and the current command value Itrg, and drives the inverter circuit 13 with the gate signal.

Description

Technical Field

[0001] The present invention relates to a power conversion device, a control method for an inverter of the power conversion device, and a control program.

Background Art

[0002] A conventional power conversion device has a configuration without a DC-DC converter relative to the circuit configuration shown in Fig. 1, and adjusts the supplied power by independently controlling the conduction angle αinv of the switches in the inverter circuit 13 and the conduction angle αarc of the switches in the rectifier 23. A technique related to this is disclosed in Patent Document 1.

[0003] Since the rectifier 23 is disposed immediately before the external power supply unit, it can be said that the control amount of the rectifier 23 most directly reflects the power supplied to the outside in the entire system. Then, as the phase difference φarc of the rectifier 23 changes, the phase difference φinv between the inverter current Iinv and the inverter voltage Vinv output from the inverter circuit 13 is also affected during operation. When the phase difference φinv increases, the conduction loss in the inverter circuit 13 increases, and the efficiency deteriorates. In addition, when the phase difference φinv falls below a predetermined value, the current during ZVS (Zero Voltage Switching) becomes insufficient, resulting in a hard switching state, which causes an increase in harmonic noise and, in some cases, destruction of FET devices.

[0004] Accordingly, there is a demand for a control scheme that corrects the phase of the inverter circuit 13 and operates in coordination with the operation of the rectifier 23, so as to achieve higher efficiency and avoid factors that increase noise.

Prior Art Literature

Patent Documents

[0005]

Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0006] Various aspects of the present invention aim to provide a power converter, a control method for the inverter of a power converter, and a control program that control an inverter circuit in response to changes in the control amount of a rectifier. [Means for solving the problem]

[0007] Various aspects of the present invention will be described below.

[0008] [1] In a power conversion device that transmits power from a power supply coil to a power output coil in a non-contact manner, thereby outputting power through a power output resonant circuit and a rectifier, A power supply side resonant circuit electrically connected to the power supply side coil, An inverter circuit electrically connected to the power supply side resonant circuit, A PFC (Power Factor Correction) circuit is electrically connected to the inverter circuit, An AC power supply electrically connected to the PFC circuit, It has, When outputting the aforementioned power, an A / D conversion circuit measures the inverter current generated by the change in the control amount of the rectifier at the timing of an arbitrary trigger signal, A PI controller that inputs the difference between the inverter current measured by the A / D conversion circuit and the current command value, A PWM control unit receives the phase amount adjusted and output by the PI controller and generates a gate signal for the inverter with the phase amount corrected, It has, A power conversion device characterized by driving the inverter circuit with the gate signal generated by the PWM control unit.

[0009] According to the power conversion device described in [1] above in one aspect of the present invention, the inverter current generated by a change in the control amount of the rectifier is measured by an A / D conversion circuit at the timing of an arbitrary trigger signal, the difference between the measured inverter current and the current command value is input to a PI controller, the phase amount adjusted and output by the PI controller is input to a PWM control unit, the PWM control unit generates an inverter gate signal with the phase amount corrected, and the inverter circuit is driven by this gate signal. The inverter current is measured and controlled in this way in order to keep the inverter current constant during ZVS and minimize conduction loss. Furthermore, the inverter circuit can be driven by an inverter gate signal generated by correcting the phase amount adjusted by the PI controller using the difference between the inverter current output from the independently controlled inverter circuit and the current command value, which is adjusted by the rectifier, in accordance with the change in the control amount of the independently controlled rectifier, and then controlled by the PWM control unit. By operating the inverter circuit in coordination with the operation of the rectifier in this way, the increase in phase difference can be suppressed, conduction loss in the inverter circuit can be reduced, and high efficiency and high noise factors can be avoided. Therefore, compared to the case where the inverter circuit is independently controlled, the power converter described in [1] above reduces conduction loss in the inverter circuit, resulting in higher efficiency and avoidance of factors that increase noise. In addition, the power converter described in [1] above makes it easier to solve the problem of the method of controlling the inverter circuit by PI control of the phase difference between the inverter current and the inverter voltage Vinv and the deviation of the phase command value. This problem is that when the phase difference is controlled to be constant based on the phase command value, if the amplitude of the inverter current changes, the current at ZVS is not constant, and conduction loss increases as the amplitude of the inverter current increases. Factors that cause fluctuations in the inverter current include changes in the coupling degree between the power supply coil and the power output coil, changes in the applied voltage to the FET, and changes in ambient temperature. To address the above problem, by acquiring the inverter current at ZVS, it becomes possible to capture the changes in the inverter current caused by these fluctuation factors. Furthermore, by setting the current command value and inputting the measured deviation of the inverter current to the PI controller to adjust the phase amount, it becomes possible to operate the gate signal with a desired current value at ZVS, enabling operation with minimized conduction loss.

[0010] [2] In the above [1], A DC-DC converter circuit is arranged between the inverter circuit and the PFC circuit. A power conversion device characterized in that the inverter circuit is electrically connected to the DC-DC converter circuit, and the DC-DC converter circuit is electrically connected to the PFC circuit.

[0011] According to the power conversion device [2] described above in one aspect of the present invention, in the power conversion device [1] described above, the DC-DC converter circuit is arranged between the inverter circuit and the PFC circuit and is electrically connected to both. By adopting such a configuration, the operating range of the voltage input to the inverter circuit can be widened.

[0012] [3] In the above [1] or [2], A power converter characterized in that the vehicle's battery is charged when the power converter outputs the power.

[0013] [4] In a power conversion device that outputs power through a rectifier by transmitting power from a power supply coil to a power output coil in a non-contact manner, An inverter circuit electrically connected to the power supply coil, An AC power supply electrically connected to the inverter circuit, A PWM control unit electrically connected to the inverter circuit, A / D conversion circuit electrically connected to the PWM control unit, It has, A power conversion device characterized in that the A / D conversion circuit measures the inverter current output from the power supply side resonant circuit to the inverter circuit at a predetermined time, reflecting the change in the control amount of the rectifier, the PWM control unit generates a gate signal for the inverter circuit based on the difference between the inverter current and the current command value, and drives the inverter circuit with the gate signal.

[0014] According to the power conversion device described in [4] above in one aspect of the present invention, the gate signal of the inverter circuit is generated based on the inverter current, which reflects the change in the control amount of the rectifier located near the power output, and the inverter circuit is driven. As a result, conduction loss in the inverter circuit is reduced, and high efficiency and factors that increase noise are avoided. In addition, the gate signal of the inverter circuit is generated based on the difference between the inverter current converted to a digital signal and the current command value, and the inverter circuit is driven by this gate signal. Conduction loss increases as the above phase difference increases, but in this configuration, since the phase difference is determined based on the current command value, phase adjustment in accordance with changes in the inverter current is possible, and conduction loss can be minimized.

[0015] [5] In the above [4], A power supply side resonant circuit is disposed between the power supply side coil and the inverter circuit and is electrically connected to both, a power output-side resonant circuit disposed between the power output-side coil and the rectifier and electrically connected to both, further comprising the power conversion device.

[0016] [6] The power conversion device according to any one of the above [4] or [5], wherein an arbitrary Trigger signal is used during A / D conversion of the inverter current.

[0017] According to the power conversion device of the above [6] according to one aspect of the present invention, when the A / D conversion circuit converts the inverter current into a digital signal, the current is acquired at the timing of an arbitrary Trigger signal. If, for example, a gate signal for driving the inverter circuit is used as the arbitrary Trigger signal, the inverter current can be acquired based on the timing of the target gate signal during ZVS operation, making it possible to measure an accurate ZVS current and improving control accuracy.

[0018] [7] A control method for an inverter circuit of a power conversion device that outputs power through a power output-side resonant circuit and a rectifier by transmitting power in a non-contact state from a power supply-side coil electrically connected to an AC power supply, a PFC circuit, an inverter circuit and a power supply-side resonant circuit to a power output-side coil, the method comprising: when outputting the power, measuring an inverter current generated by a change in a control amount of the rectifier at a timing of an arbitrary Trigger signal, adjusting a phase amount by PI control based on a difference between the measured inverter current and a current command value, generating a gate signal of the inverter by PWM control based on the phase amount, and driving the inverter circuit by the gate signal.

[0019] According to the control method for an inverter of a power conversion device of the above [7] according to one aspect of the present invention, the same effects as the power conversion device of the above [1] can be expected.

[0020] [8] The method according to the above [7], A method for controlling the inverter of a power converter, characterized in that the onboard battery is charged when the power converter outputs the power.

[0021] [9] In a power conversion device that outputs power through a rectifier by transmitting power from a power supply coil to a power output coil in a non-contact manner, An inverter circuit electrically connected to the power supply coil, An AC power supply electrically connected to the inverter circuit, A PWM control unit electrically connected to the inverter circuit, A / D conversion circuit electrically connected to the PWM control unit, It has, A method for controlling the inverter of a power converter, characterized by measuring the inverter current generated by a change in the control amount of the rectifier at the timing of an arbitrary trigger signal, generating a gate signal for the inverter circuit based on the difference between the inverter current and the current command value, and driving the inverter circuit with the gate signal.

[0022] According to one aspect of the present invention, the inverter control method for the power converter described in [9] above generates a gate signal for the inverter circuit based on the inverter current, which reflects the change in the control amount of the rectifier located near the power output, and drives the inverter circuit. Therefore, even if the operating state of the rectifier changes, conduction loss in the inverter circuit can be reduced, and high efficiency and high noise factors can be avoided. In addition, the gate signal for the inverter circuit is generated based on the difference between the inverter current converted to a digital signal and the current command value, and the inverter circuit is driven by this gate signal. Conduction loss increases as the above phase difference increases, but in this configuration, since the phase difference is determined based on the current command value, phase adjustment in accordance with changes in the inverter current is possible, and conduction loss can be minimized.

[0023]

[10] The power converter described in [1] above has a control program that implements multiple functions, The aforementioned multiple functions are, (a) A function to measure the inverter current output from the inverter circuit at the timing of an arbitrary trigger signal, (b) A function that calculates the difference between the measured inverter current and the current command value and inputs it to the PI controller, The PI controller has a function (c) of outputting a PI-controlled adjusted phase amount, where the phase difference between the measured inverter current and the current command value is PI controlled, to the PWM control unit. The PWM control unit has a function (d) to generate the gate signal of the inverter in accordance with the adjusted phase amount, (e) A function to drive the inverter circuit with the generated gate signal, A power conversion device characterized by having the following features.

[0024] A power conversion device according to one aspect of the present invention

[10] has a control program that realizes the above functions (a) to (e). This enables control based on feedback from a rectifier adjacent to the power output section to the inverter circuit. Compared to independent control of the inverter circuit, this control allows for control in response to fluctuating factors, reduces conduction loss in the inverter circuit, and improves efficiency and avoids factors that increase noise.

[0025]

[11] A rectifier electrically connected to a power output coil that receives power from a power supply coil in a non-contact manner, and which supplies the rectified current and voltage of the input current to the outside, An inverter circuit that receives an inverter voltage and inverter current input that reflects the output from the rectifier, transmitted from the power output coil to the power supply coil via a power supply side resonant circuit, and receives and converts an AC voltage and AC current input, and outputs it to the power supply coil via the electrically connected power supply side resonant circuit, A PWM control unit connected to the inverter circuit, A PI controller connected to the PWM control unit, A phase detector connected to the PI controller, A conversion unit connected to the PI controller, A program for controlling a power converter having, (a) A step of measuring the inverter current output from the inverter circuit when an arbitrary trigger signal is input, (b) the step of calculating the difference between the measured inverter current and the current command value and inputting it to the PI controller, The PI controller outputs a PI-controlled adjusted phase amount, where the phase difference between the measured inverter current and the current command value is PI controlled, to the PWM control unit (c). The PWM control unit performs the step (d) of generating a gate signal for the inverter corresponding to the adjusted phase amount, Step (e) of driving the inverter circuit with the generated gate signal, A control program that causes a computer to execute something.

[0026] In a device using the control program described in

[11] above according to one aspect of the present invention, power is transmitted from the power output coil to the power supply coil. For this reason, the output from the rectifier is reflected in step (a) of measuring the inverter current output from the inverter circuit at the timing of an arbitrary trigger signal. Subsequently, the difference between the measured inverter current and the current command value is calculated and input to the PI controller in step (b), thereby PI-controlled. The PI controller outputs the PI-controlled adjusted phase amount to the PWM control unit (step (c)), the PWM control unit generates a gate signal for the inverter corresponding to the adjusted phase amount (step (d)), and drives the inverter circuit with the generated gate signal (step (e)). As a result, control based on feedback from the rectifier, which is close to the power supply unit to the outside, to the inverter circuit is possible. Compared to independent control of the inverter circuit, this control enables control according to fluctuating factors, reduces conduction loss in the inverter circuit, improves efficiency, and avoids factors that increase noise. [Effects of the Invention]

[0027] According to various aspects of the present invention, it is possible to provide a power conversion device that achieves high efficiency by reducing conduction loss and avoids factors that increase noise, as well as a control method and control program for its inverter. [Brief explanation of the drawing]

[0028] [Figure 1] This is a circuit diagram illustrating a power conversion device according to one aspect of the present invention. [Figure 2] Figure 1 shows a detailed circuit diagram and schematic diagram illustrating the control of the power supply inverter. [Figure 3] This is a circuit diagram illustrating a power conversion device 40 according to one aspect of the present invention. [Figure 4] Figure 2 is a schematic diagram showing the results of the inverter control. [Figure 5] This flowchart illustrates a program that reduces conduction losses by controlling the inverter on the power supply side, as shown in Figure 2. [Modes for carrying out the invention]

[0029] Embodiments of the present invention will be described in detail below with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and that its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention shall not be construed as being limited to the descriptions of the embodiments shown below.

[0030] Figure 1 is a circuit diagram illustrating a power conversion device according to one aspect of the present invention. Figure 2 is a circuit diagram and schematic diagram illustrating in detail the control of the power output side inverter circuit 13 shown in Figure 1. Figure 3 is a circuit diagram illustrating a power conversion device 40 according to one aspect of the present invention. Figure 4 is a schematic diagram showing the result of controlling the inverter shown in Figure 2. Figure 5 is a flowchart illustrating a program that reduces conduction loss by controlling the power output side inverter shown in Figure 2.

[0031] The power converter 40 shown in Figure 3 is a system that transmits power from the power supply coil 11 of the power supply system 40GA to the power output coil 21 of the power output system 40VA in a non-contact manner. It is desirable that the power supply coil 11 and the power output coil 21 face each other and that the distance between them is a predetermined distance. This predetermined distance can be appropriately changed to a suitable distance according to the application of the device. The power supply coil 11 and the power output coil 21 transmit power to each other by electromagnetic induction. This power transmission can be performed using a magnetic field resonance method by adding a resonant circuit, described later, to the power converter 40.

[0032] As shown in Figure 3, the power converter 40 has a power supply coil 11, to which an inverter circuit 13 is electrically connected. A power supply 46 is electrically connected to the inverter circuit 13, and an AC voltage corresponding to the gate signal drive frequency is output to the power supply coil 11. The power supply 46 is assumed to be a DC power supply. This causes the current flowing through the power supply coil 11 to fluctuate, generating an electromotive force in the power output coil 21, and AC power is input to the rectifier 23 electrically connected to the power output coil 21. In the rectifier 23, a configuration in which the conduction angle αarc is actively varied is also called an Active Rectifier (ARC). The voltage and current converted to DC by the rectifier 23 become the output of the power converter 40. Alternatively, a configuration without a rectifier 23 is possible. In this case, AC power is output to the outside of the power converter 40.

[0033] To understand the electrical state of the power converter 40, eight voltage and current measurement points P_S1, P_S2, P_inv1, P_inv2, P_arc1, P_arc2, P_O1, and P_O2 can be provided. Of these measurement points, P_inv1 and P_inv2 are essential in this embodiment, while the others may be provided at will. By providing P_S1 on one of the two conductive wires electrically connecting the power supply 46 and the inverter circuit 13, and P_S2 on the other, the voltage and current values ​​applied from the power supply 46 to the inverter circuit 13 can be measured. By providing P_inv1 and P_inv2, the voltage and current values ​​between the inverter circuit 13 and the power supply coil 11 can be measured. By providing P_arc1 on one of the two conductive wires electrically connecting the power output coil 21 and the rectifier 23, and P_arc2 on the other, the voltage and current values ​​between the power output coil 21 and the rectifier 23 can be measured. By providing P_O1 on one of the two conductive wires that output power from the rectifier 23 to the outside and P_O2 on the other, the voltage and current values ​​output from the rectifier 23 to the outside can be measured.

[0034] To set the external output power from the rectifier 23 to a specified value, the measured power is calculated from the output current measured at P_O1 or P_O2 and the output voltage between P_O1 and P_O2, and the conduction angle of the rectifier 23 is adjusted so that the external output power reaches the specified value.

[0035] As the phase difference φarc between the voltage Varc applied from the rectifier 23 to the power output coil 21 and the current Iarc flowing from the rectifier 23 to the power output coil 21 changes, the phase difference φinv of the inverter circuit 13 is also affected and fluctuates. As φinv increases, the conduction loss of the switching elements constituting the inverter circuit increases.

[0036] By measuring the inverter voltage Vinv using P_inv1 and P_inv2, and the inverter current Iinv using either P_inv1 or P_inv2, the following feedback control can be achieved.

[0037] First, let's explain the inverter circuit 13 shown in the upper part of Figure 2, which is the object of control. The inverter circuit 13 consists of four elements: Qinv_A, Qinv_B, Qinv_C, and Qinv_D, each being a pair of diodes and transistors. The following explanation assumes that four measurement points, P_S1, P_S2, P_inv1, and P_inv2, are provided in the circuit.

[0038] The four elements Qinv_A, Qinv_B, Qinv_C, and Qinv_D are each controlled by the voltage of the gate signal indicated by the arrow in the diagram. When a voltage is applied to the gate terminals of Qinv_A and Qinv_D, Qinv_A and Qinv_D conduct and the voltage of power supply 46 is output to Vinv (State 1). When a voltage is applied to the gate terminals of Qinv_B and Qinv_D, the voltage of power supply 46 is output to Vinv (State 2). By repeating the outputs of State 1 and State 2, the DC voltage of power supply 46 is output to Vinv as an AC voltage. By repeating the outputs of State 1 and State 2, the DC voltage of power supply 46 is reversed in polarity and output to Vinv as an AC voltage.

[0039] Next, a method for modifying and generating a gate signal, which is a control signal, will be described. As shown in the middle section of Figure 2, the power converter 40 has an A / D conversion circuit 31 that measures the inverter current Iinv input from the power supply coil 11 to the inverter circuit 13 at the timing of an arbitrary trigger signal. In addition, the power converter 40 has a calculation unit (represented in the figure by a symbol with the letter Σ inside a circle) that receives input of the inverter current Iinv converted by the A / D conversion circuit 31 and the current command value Itrg, and calculates the difference between them, ierr. When this difference ierr is input, the power converter 40 has a PI controller 33 that outputs a PI-controlled phase amount φout. Furthermore, the power converter 40 has a PWM control unit 34 that, when the phase amount φout is input, generates and outputs a PWM-controlled gate signal (indicated as Gate Signal in the figure) for the inverter circuit 13, as shown in detail in the upper section of Figure 2. The calculation of the difference ierr between the inverter current Iinv and the current command value Itrg, which is performed in the calculation unit, may be performed by the PI controller 33 by inputting the inverter current Iinv and the current command value Itrg to the PI controller 33.

[0040] To output the gate signal described above, the control by the A / D conversion circuit 31, calculation unit, PI controller 33, and PWM control unit 34 described above is repeated. The trigger signal used in the A / D conversion circuit 31 can be any signal. For example, if the gate signal for driving the inverter circuit 13 is used, the inverter current can be obtained based on the timing of the target gate signal during ZVS operation, making it possible to measure the ZVS current accurately and improving control accuracy. Alternatively, an external signal that is sufficiently faster than the period of the gate signal may be used as the trigger signal.

[0041] When power is output through the rectifier 23, the current Iarc flowing out of the rectifier 23 most directly reflects the power supplied to the outside among the power conversion devices 40. Based on the inverter current Iinv, which reflects the change in this current Iarc, a gate signal for the inverter circuit 13 is generated and the inverter circuit 13 is driven. As a result, conduction loss in the inverter circuit 13 is reduced, and high efficiency and factors that increase noise are avoided. In addition, a gate signal for the inverter circuit 13 is generated based on the difference between the inverter current Iinv converted to a digital signal and the current command value Itrg, and the inverter circuit 13 is driven by this gate signal. Conduction loss increases when the phase difference between the inverter current Iinv and the gate signal of the inverter circuit 13 increases, but in this configuration, since the phase difference is determined based on the current command value, phase adjustment according to changes in the inverter current is possible and conduction loss can be minimized.

[0042] In the case where the power converter 40 does not have a rectifier 23, the power supplied to the outside is most directly reflected in the power converter 40 by the current value flowing through the power supply system 40VA and the voltage values ​​measured by P_arc1 and P_arc2. The same effect as above can be obtained by controlling it in the same way as above based on the inverter current Iinv which is affected by these current and voltage values.

[0043] The A / D conversion circuit 31 receives the inverter current Iinv and the trigger signal as inputs. These inputs are received via conductive wires connected to the power supply coil 11, and the gate signal may be transmitted to the inverter circuit 13 via the conductive wires. Alternatively, as shown in the lower part of Figure 2, all or some of the components in the above configuration may not be physically connected to the power converter 40, and communication between the input to and output of these components and the power converter 40 may be performed wirelessly.

[0044] Figure 4 shows how conduction loss is reduced in this embodiment, when the power supply 46 is a DC power supply. The gate signal for driving the inverter circuit 13 is used as the trigger signal. The top row of Figure 4 shows the trigger signal, and the second row shows the waveform of the inverter current Iinv when the trigger signal is not modified. As shown in the figure, the value of the inverter current Iinv at the start of the trigger signal input, iinv, is a negative value, and the inverter voltage Vinv is a positive value, but the inverter current Iinv is a negative value until the value of the inverter current Iinv becomes zero. Therefore, conduction loss occurs from the time the value of the inverter current Iinv is iinv until it becomes zero. Since the trigger signal is not modified, the conduction loss per control cycle does not change.

[0045] The third row from the top of Figure 4 shows the modified gate signal, or trigger signal, for driving the inverter circuit 13, and the bottom row of Figure 4 shows the waveform of the inverter current Iinv from the second row of Figure 4 again. The timing of the trigger signal input start is modified and gradually becomes later, and as the value of the inverter current Iinv at the start of the trigger signal input approaches the current command value Itrg, the conduction loss decreases. In the example shown, at the rightmost timing of the trigger signal input start, the value of the inverter current Iinv becomes the current command value Itrg, which is the control target state when ZVS is considered.

[0046] (Embodiment 2) The power converter shown in Figure 1 is an additional component to the power converter 40 shown in Figure 3. The inverter circuit 13 of the power supply system GA is electrically connected to the DC-DC converter 14, and the DC-DC converter 14 is electrically connected to the PFC (Power Factor Correction) circuit 15. The AC power supply 16 is electrically connected to the PFC circuit 15. The rectifier 23 of the power output system VA is electrically connected to the power supply resonant circuit 22, and the power supply resonant circuit 22 is electrically connected to the power supply coil 21. A smoothing capacitor Cr is connected in parallel to the rectifier 23, and the battery 24 is electrically connected to it.

[0047] Let's further explain the power supply system GA. The DC-DC converter 14 makes it possible to broaden the voltage input from the PFC circuit 15 and input it to the inverter circuit 13. The AC power supply 16 can be replaced with a DC power supply, and if a DC power supply is used, it is possible to have a configuration without one or both of the PFC circuit 15 and the DC-DC converter 14.

[0048] The power supply side resonant circuit 12 and the power output side resonant circuit 22 enable power transmission using a magnetic field resonance method. Specifically, the DS (Double Sided)-LCC method and the SS method are envisioned as the methods for the power supply side resonant circuit 12 and the power output side resonant circuit 22. In the DS-LCC method, the power supply side resonant circuit 12 is a circuit consisting of a capacitor and a coil connected in series with the power supply side coil 11, as well as a capacitor connected in parallel, and the power output side resonant circuit 22 is a similar circuit with respect to the power output side coil 21. In the SS method, the power supply side resonant circuit 12 is a capacitor connected in series with the power supply side coil 11, and the power output side resonant circuit 22 is a capacitor connected in series with the power output side coil 21.

[0049] Power transmission from the power supply system GA to the power output system VA is performed using a magnetic field resonance method. The distance between the power output coil 21 and the power supply coil 11 during power transmission may be appropriately changed according to the application of the power converted by this invention. Ideally, the power output coil 21 should be in the optimal position for power transmission relative to the power supply coil 11, i.e., the position where the transmitted power is maximized, but power transmission can still be performed even if it is deviated from this optimal position. In the above magnetic field resonance method, the reduction in transmitted power due to the above positional deviation can be suppressed by appropriately configuring the resonant circuit. The presence of a smoothing capacitor Cr enables smoothing of the current and, consequently, the power supplied from the rectifier 23 to the battery 24. The battery 24 is an on-board battery when supplying power to an electric vehicle by the power conversion device, and some kind of energy storage device when supplying power to something other than an electric vehicle.

[0050] The effects and advantages of this embodiment will be explained with reference to Figures 1 and 2. In this embodiment, it is essential to measure the inverter current Iinv flowing from the power supply side resonant circuit 12 to the inverter circuit 13. Measuring other current and voltage values ​​in the circuit is optional.

[0051] In this embodiment, the inverter current Iinv, which is input from the power supply side resonant circuit 12 to the inverter circuit 13 and reflects the change in the current Iarc flowing out from the rectifier 23 near the battery 24, is measured by the A / D conversion circuit 31 at the timing of an arbitrary trigger signal. The difference between the measured inverter current Iinv and the current command value Itrg is input to the PI controller 33, and the phase amount φout, which is adjusted and output by the PI controller 33, is input to the PWM control unit 34, which generates the gate signal of the inverter by correcting the phase amount φout. The inverter circuit 13 is driven by this gate signal. The reason for measuring and controlling the inverter current Iinv in this way is to keep the inverter current Iinv constant during ZVS and minimize conduction loss. In this embodiment, the inverter gate signal is also generated by the PWM control unit 34 correcting the phase amount φout, which is adjusted by the PI controller 33 using the difference between the inverter current Iinv output from the inverter circuit 13, which is affected by the change in the control amount of the rectifier 23, and the current command value Itrg. The gate signal of the inverter generated is then used to drive the inverter circuit 13. By operating the inverter circuit 13 in coordination with the operation of the rectifier 23 in this way, the increase in the phase difference φinv can be suppressed, the conduction loss in the inverter circuit 13 is reduced, and higher efficiency and avoidance of noise-generating factors can be achieved.

[0052] The effects of the operation of the inverter circuit 13 in coordination with the operation of the rectifier 23 described above will be explained in detail below. The power output transmitted from the power supply coil 11 to the power output coil 21 is performed through the rectifier 23. Here, a gate signal is generated based on the change in the control amount of the rectifier 23, and the inverter circuit 13 is driven by this gate signal. In the above feedback control, the gate signal is modified so that the phase difference φinv between the inverter current Iinv and the inverter voltage Vinv output from the inverter circuit 13 is greater than or equal to a predetermined value that does not result in a current shortage during ZVS, and is as small as possible. For this reason, in the power conversion device of this embodiment, the conduction loss in the inverter circuit 13 is reduced compared to the case where the inverter circuit is controlled independently, resulting in higher efficiency and avoidance of factors that increase noise. In addition, the power conversion device of this embodiment makes it easier to solve the problems of the method of controlling the inverter circuit 13 by PI control of the deviation between the phase difference φinv between the inverter current Iinv and the inverter voltage Vinv and the phase command value φtrg. This problem arises when the phase difference φinv is controlled to be constant based on the phase command value φtrg. If the amplitude of the inverter current changes, the current during ZVS (Zero-Variable State) will not be constant, and the conduction loss will increase as the amplitude of the inverter current increases. Factors causing fluctuations in the inverter current include changes in the coupling degree between the power supply coil and the power output coil, changes in the applied voltage to the FET (Field Effect Transistor), and changes in ambient temperature. To address this problem, as shown in Figure 4, the change in the inverter current Iinv caused by these fluctuations can be captured by acquiring the inverter current during ZVS. Furthermore, by setting the current command value Itrg and inputting the difference between it and the measured inverter current Iinv to the PI controller 33 to adjust the phase amount φout, it becomes possible to operate the gate signal with a desired current value during ZVS, enabling operation with minimized conduction loss.

[0053] Furthermore, according to this embodiment, the DC-DC converter circuit 14, which is positioned between the inverter circuit 13 and the PFC circuit 15 and electrically connected to both, can widen the operating range of the voltage input to the inverter circuit 13.

[0054] Furthermore, in this embodiment, in order to control the inverter circuit 13 of a power converter that outputs power through a power output resonant circuit 22 and a rectifier 23 by transmitting power in a non-contact manner from a power supply side coil 11 electrically connected to an AC power supply 16, a PFC circuit 15, an inverter circuit 13, and a power supply side resonant circuit 12 to a power output side coil 21, the inverter current Iinv input from the power supply side resonant circuit 12 to the inverter circuit 13, which is generated by the change in the control amount of the rectifier 23 when the above power is output, is measured at the timing of an arbitrary trigger signal, the phase amount φout is adjusted by PI control based on the difference between the measured inverter current Iinv and the current command value Itrg, the gate signal of the inverter is generated by PWM control based on the phase amount φout, and the inverter circuit 13 is driven by that gate signal. The reason for measuring and controlling the inverter current Iinv in this way is to keep the inverter current Iinv constant during ZVS and minimize conduction loss. In this embodiment, the PWM control unit 34 modifies the phase amount φout, which is adjusted by the PI controller 33 using the difference between the inverter current Iinv output from the inverter circuit 13 (which is affected by changes in the control amount of the rectifier 23) and the current command value Itrg, to generate the gate signal for the inverter. The inverter circuit 13 is then driven by the generated gate signal for the inverter. By operating the inverter circuit 13 in coordination with the operation of the rectifier 23 in this way, the increase in the phase difference φinv can be suppressed, conduction loss in the inverter circuit 13 can be reduced, and efficiency and factors that increase noise can be avoided.

[0055] The effects of the operation of the inverter circuit 13 in coordination with the operation of the rectifier 23 described above will be explained in detail below. The power output transmitted from the power supply coil 11 to the power output coil 21 is performed through the rectifier 23. Here, a gate signal is generated based on the change in the control amount of the rectifier 23, and the inverter circuit 13 is driven by this gate signal. In the above feedback control, the gate signal is modified so that the phase difference φinv between the inverter current Iinv and the inverter voltage Vinv output from the inverter circuit 13 is greater than or equal to a predetermined value that does not result in a current shortage during ZVS, and is as small as possible. For this reason, in the power conversion device of this embodiment, the conduction loss in the inverter circuit 13 is reduced compared to the case where the inverter circuit is controlled independently, resulting in higher efficiency and avoidance of factors that increase noise. In addition, the power conversion device of this embodiment makes it easier to solve the problems of the method of controlling the inverter circuit 13 by PI control of the deviation between the phase difference φinv between the inverter current Iinv and the inverter voltage Vinv and the phase command value φtrg. This problem arises when the phase difference φinv is controlled to be constant based on the phase command value φtrg. If the amplitude of the inverter current changes, the current during ZVS (Zero-Variable State) will not be constant, and the conduction loss will increase as the amplitude of the inverter current increases. Factors causing fluctuations in the inverter current include changes in the coupling degree between the power supply coil and the power output coil, changes in the applied voltage to the FET (Field Effect Transistor), and changes in ambient temperature. To address this problem, as shown in Figure 4, the change in the inverter current Iinv caused by these fluctuations can be captured by acquiring the inverter current during ZVS. Furthermore, by setting the current command value Itrg and inputting the difference between it and the measured inverter current Iinv to the PI controller 33 to adjust the phase amount φout, it becomes possible to operate the gate signal with a desired current value during ZVS, enabling operation with minimized conduction loss.

[0056] Furthermore, the power conversion system 40 may have a control program that implements multiple functions. These multiple functions may include the following functions (a) to (e).

[0057] Function (a): A function to measure the inverter current Iinv output from the inverter circuit at the timing of an arbitrary trigger signal.

[0058] Function (b): A function that calculates the difference between the measured inverter current Iinv and the current command value Itrg and inputs it to the PI controller.

[0059] Function (c): A function that outputs a PI-controlled adjusted phase amount φout to the PWM control unit, which is the phase difference between the measured inverter current Iinv and the current command value Itrg from the PI controller.

[0060] Function (d): A function in the PWM control unit that generates the gate signal for the inverter circuit in accordance with the adjusted phase amount φout.

[0061] Function (e): The function of driving the inverter circuit with the generated gate signal.

[0062] According to the control program of this embodiment, by using a control program that realizes the above functions (a) to (e), control based on feedback from the rectifier 23 adjacent to the battery 24 to the inverter circuit 13 is possible. Compared to independent control of the inverter circuit 13, this control allows for control in response to fluctuating factors, reduces conduction loss in the inverter circuit 13, and improves efficiency and avoids factors that increase noise.

[0063] Figure 5 is a flowchart illustrating a program that performs control based on feedback from the rectifier 23 to the inverter circuit 13, as shown in Figures 1 and 2. This control program can be implemented by having a computer run it, and the power conversion system shown in Figure 1 may have this control program.

[0064] This control program controls a power converter having, as shown in Figure 1, a power output coil 21 to which power is transmitted in a non-contact manner from a power supply coil 11, a rectifier 23 that supplies a rectified current and voltage from the input current to a battery 24, an inverter circuit 13 that receives an inverter voltage Vinv and inverter current Iinv that are transmitted from the power output coil 11 to the power supply coil 21 and reflect the output from the rectifier 23 via a power supply side resonant circuit 22, and receives and converts an AC voltage and AC current input and outputs to the power supply coil 11 via an electrically connected power supply side resonant circuit 12, a PWM control unit 34 connected to the inverter circuit 13, a PI controller 33 connected to the PWM control unit 34, and an A / D conversion circuit 31 connected to the PI controller 33.

[0065] As shown in Figure 5, when an arbitrary trigger signal is input, the inverter current Iinv output from the inverter circuit 13 is measured (step (a)).

[0066] Next, the difference between the measured inverter current Iinv and the current command value Itrg is calculated and input to the PI controller (step (b)).

[0067] Next, the PI controller outputs the adjusted phase amount φout, which is the phase difference between the measured inverter current Iinv and the current command value Itrg, to the PWM control unit (step (c)). Next, the PWM control unit generates the gate signal for the inverter circuit corresponding to the adjusted phase amount φout (step (d)). Next, the generated gate signal drives the inverter circuit (step (e)).

[0068] According to the control program described above, power is transmitted from the power output coil 21 to the power supply coil 11. Therefore, the output from the rectifier 23 is reflected in step (a) of measuring the inverter current Iinv output from the inverter circuit 13 at the timing of an arbitrary trigger signal. Subsequently, the difference between the measured inverter current Iinv and the current command value Itrg is calculated and input to the PI controller 33 in step (b), thereby performing PI control on the difference. The PI controller 33 outputs the PI-controlled adjusted phase amount φout to the PWM control unit 34 (step (c)), the PWM control unit 34 generates a gate signal for the inverter circuit 13 corresponding to the adjusted phase amount φout (step (d)), and drives the inverter circuit 13 with the generated gate signal (step (e)). As a result, control based on feedback from the rectifier 23, which is close to the battery 24, to the inverter circuit 13 is possible. Compared to independent control of the inverter circuit 13, this control allows for control in response to fluctuating factors, reduces conduction losses in the inverter circuit 13, and improves efficiency and avoids factors that increase noise. [Explanation of Symbols]

[0069] 11 Power supply coil 12 Power supply side resonant circuit 13 Inverter Circuit 14. DC-DC converter circuit 15 PFC circuit 16 AC power supply 21 Power output side coil 22 Power output side resonant circuit 23 Rectifier 24 batteries 31 A / D conversion circuit 33 PI controller 34 PWM control unit 46 Power supply

Claims

1. In a power conversion device that transmits power from a power supply coil to a power output coil in a non-contact manner, thereby outputting power through a power output resonant circuit and a rectifier, A power supply side resonant circuit electrically connected to the power supply side coil, An inverter circuit electrically connected to the power supply side resonant circuit, A PFC circuit electrically connected to the inverter circuit, An AC power supply electrically connected to the PFC circuit, It has, When outputting the aforementioned power, an A / D conversion circuit measures the inverter current generated by the change in the control amount of the rectifier at the timing of an arbitrary trigger signal, A PI controller inputs the difference between the inverter current measured by the A / D conversion circuit and the current command value, A PWM control unit receives the phase amount adjusted and output by the PI controller and generates a gate signal for the inverter with the phase amount corrected, It has, A power conversion device characterized by driving the inverter circuit with the gate signal generated by the PWM control unit.

2. In claim 1, A DC-DC converter circuit is arranged between the inverter circuit and the PFC circuit. A power conversion device characterized in that the DC-DC converter circuit is electrically connected to the inverter circuit, and the PFC circuit is electrically connected to the DC-DC converter circuit.

3. In claim 1 or 2, A power converter characterized in that the vehicle's battery is charged when the power converter outputs the power.

4. In a power conversion device that outputs power through a rectifier by transmitting power from a power supply coil to a power output coil in a non-contact manner, An inverter circuit electrically connected to the power supply coil, An AC power supply electrically connected to the inverter circuit, A PWM control unit electrically connected to the inverter circuit, An A / D conversion circuit electrically connected to the PWM control unit, It has, A power conversion device characterized in that the A / D conversion circuit measures the inverter current output from the power supply side resonant circuit to the inverter circuit at a predetermined time, reflecting the change in the control amount of the rectifier, the PWM control unit generates a gate signal for the inverter circuit based on the difference between the inverter current and the current command value, and drives the inverter circuit with the gate signal.

5. In claim 4, A power supply side resonant circuit is disposed between the power supply side coil and the inverter circuit and is electrically connected to both, A power output side resonant circuit is disposed between the power output side coil and the rectifier and electrically connected to both, A power conversion device characterized by further having the following.

6. In claim 4 or 5, A power conversion device characterized by using an arbitrary trigger signal during A / D conversion of the inverter current.

7. A control method for the inverter circuit of a power converter that outputs power through a power output resonant circuit and a rectifier by transmitting power in a non-contact manner from a power supply coil electrically connected to an AC power source, a PFC circuit, an inverter circuit, and a power supply side resonant circuit to a power output side coil, When outputting the aforementioned power, the inverter current generated by the change in the control amount of the rectifier is measured at the timing of an arbitrary trigger signal. The phase amount is adjusted by PI control based on the difference between the measured inverter current and the current command value. The gate signal of the inverter is generated by PWM control based on the aforementioned phase amount. A method for controlling the inverter of a power conversion device, characterized in that the inverter circuit is driven by the gate signal.

8. In claim 7, A method for controlling the inverter of a power converter, characterized in that the onboard battery is charged when the power converter outputs the power.

9. In a power conversion device that outputs power through a rectifier by transmitting power from a power supply coil to a power output coil in a non-contact manner, An inverter circuit electrically connected to the power supply coil, An AC power supply electrically connected to the inverter circuit, A PWM control unit electrically connected to the inverter circuit, An A / D conversion circuit electrically connected to the PWM control unit, It has, A method for controlling the inverter of a power converter, characterized by measuring the inverter current output from the power supply side resonant circuit to the inverter circuit at a predetermined time, reflecting the change in the control amount of the rectifier, generating a gate signal for the inverter circuit based on the difference between the inverter current and the current command value, and driving the inverter circuit with the gate signal.

10. The power conversion device described in claim 1 has a control program that realizes multiple functions, The aforementioned multiple functions are, A function (a) that measures the inverter current output from the inverter circuit at the timing of an arbitrary trigger signal, (b) A function that calculates the difference between the measured inverter current and the current command value and inputs it to the PI controller, The PI controller has a function (c) of outputting a PI-controlled adjusted phase amount, where the phase difference between the measured inverter current and the current command value is PI controlled, to the PWM control unit. The PWM control unit has a function (d) that generates a gate signal for the inverter circuit corresponding to the adjusted phase amount, (e) A function to drive the inverter circuit with the generated gate signal, A power conversion device characterized by having the following features.

11. A rectifier is electrically connected to a power output coil that receives power from a power supply coil in a non-contact manner, and supplies the rectified current and voltage of the input current to the outside. An inverter circuit that receives an inverter voltage and inverter current input that reflects the output from the rectifier, transmitted from the power output coil to the power supply coil via a power supply side resonant circuit, and receives and converts an AC voltage and AC current input, and outputs it to the power supply coil via the electrically connected power supply side resonant circuit, A PWM control unit connected to the inverter circuit, A PI controller connected to the PWM control unit, A phase detector connected to the PI controller, The A / D conversion circuit connected to the PI controller, A program for controlling a power converter having, (a) A step of measuring the inverter current output from the inverter circuit when an arbitrary trigger signal is input, (b) the step of calculating the difference between the measured inverter current and the current command value and inputting it to the PI controller, Step (c) of outputting the PI controller to the PWM control unit an adjusted phase amount controlled by PI, where the phase difference between the measured inverter current and the current command value is PI controlled. The PWM control unit performs the step (d) of generating a gate signal for the inverter circuit corresponding to the adjusted phase amount, Step (e) of driving the inverter circuit with the generated gate signal, A control program that causes a computer to execute something.

Images