Method and device for measuring impedance of battery

Abstract

The invention discloses a method and a device for measuring battery impedance. The method comprises the following steps: acquiring a sampling voltage signal and a sampling current signal of an output end of a battery; processing the sampling voltage signal through a first SOGI module to obtain an AC voltage signal; processing the sampling current signal through a second SOGI module to obtain an alternating current signal; obtaining a first DC voltage signal based on the AC voltage signal and the cosine signal; obtaining a second DC voltage signal based on the AC voltage signal and the sinusoidal signal; the cosine signal and the sine signal are obtained by processing the sampling current signal based on the second SOGI module; obtaining a direct current signal based on the alternating current signal and the sinusoidal signal; and performing division operation on the first direct-current voltage signal and the direct-current signal to obtain real part impedance of the battery, and performing division operation on the second direct-current voltage signal and the direct-current signal to obtain imaginary part impedance of the battery. The calculation amount of the AC impedance of the battery can be reduced.

Description

Technical Field

[0001] The present application relates to the field of electronic circuit technology, and in particular to a method and device for measuring battery impedance. Background Art

[0002] During the operation of the battery, by analyzing the AC impedance of the battery, real-time online monitoring of the battery operation can be achieved. In order to calculate the AC impedance of the battery, it is first necessary to superimpose the AC harmonic current of the specified frequency on the battery output current. At this time, the AC impedance of the battery at the specified frequency can be calculated by sampling the voltage and current on the battery output side. At present, the harmonic components on the battery output current are usually generated by adjusting the direct current / direct current converter (DC / DC) converter on the battery output side. At the same time, after sampling the voltage and current, the AC impedance of the battery is calculated through fast Fourier transform (FFT) analysis. However, the FFT algorithm is complex and requires a large amount of calculation. Summary of the invention

[0003] The embodiments of the present application provide a method and device for measuring battery impedance, which can reduce the amount of calculation of the AC impedance of the battery.

[0004] A first aspect of an embodiment of the present application provides a method for measuring battery impedance, comprising:

[0005] Acquire a sampled voltage signal and a sampled current signal at the output end of the battery;

[0006] The sampled voltage signal is processed by a first generalized second-order integrator SOGI module to obtain an AC voltage signal;

[0007] Processing the sampled current signal through a second SOGI module to obtain an alternating current signal;

[0008] Based on the AC voltage signal and the cosine signal, a first DC voltage signal is obtained;

[0009] Based on the AC voltage signal and the sine signal, a second DC voltage signal is obtained; the cosine signal and the sine signal are obtained by processing the sampled current signal based on the second SOGI module;

[0010] Obtaining a direct current signal based on the alternating current signal and the sinusoidal signal;

[0011] The first DC voltage signal and the DC current signal are divided to obtain the real impedance of the battery, and the second DC voltage signal and the DC current signal are divided to obtain the imaginary impedance of the battery.

[0012] Among them, the second-order generalized integrator (SOGI) module has a transfer function with infinite gain within a specific frequency, and SOGI can generate two mutually orthogonal signals at the same time.

[0013] In the embodiment of the present application, the AC impedance of the battery includes the real impedance and imaginary impedance of the battery. In the process of calculating the AC impedance of the battery, only addition, subtraction, multiplication and division operations are needed, and no complex operations such as trigonometric functions and square root extraction are involved. After obtaining the DC quantity (the first DC voltage signal, the second DC voltage signal and the DC current signal), the calculation of the impedance does not need to be run during the interruption, which greatly reduces the time consumption of the interruption. There is no need for a large number of arrays to store data, and it has real-time performance. And it is an open-loop calculation, and there is no need to consider the interference of parameter adjustment and output signals.

[0014] Optionally, obtaining a first DC voltage signal based on the AC voltage signal and the cosine signal includes:

[0015] Multiplying the AC voltage signal and the cosine signal to obtain a first superimposed voltage signal;

[0016] The first superimposed voltage signal is filtered to obtain a first direct current voltage signal.

[0017] Optionally, obtaining a second DC voltage signal based on the AC voltage signal and the sinusoidal signal includes:

[0018] Multiplying the AC voltage signal and the sinusoidal signal to obtain a second superimposed voltage signal;

[0019] The second superimposed voltage signal is filtered to obtain a second DC voltage signal.

[0020] Optionally, obtaining a direct current signal based on the alternating current signal and the sinusoidal signal includes:

[0021] Multiplying the alternating current signal and the sinusoidal signal to obtain a superimposed current signal;

[0022] The superimposed current signal is filtered to obtain a direct current signal.

[0023] Optionally, the first SOGI module includes: a first subtractor, a second subtractor, a first amplifier, a second amplifier, a first multiplier, a second multiplier, a first integrator and a second integrator; the first input end of the first subtractor is connected to the output end of the voltage sampling module, the second input end of the first subtractor is connected to the output end of the first integrator and the second input end of the second multiplier, the output end of the first subtractor is connected to the input end of the first amplifier, the output end of the first amplifier is connected to the first input end of the second subtractor, the second input end of the second subtractor is connected to the output end of the second integrator, the output end of the second subtractor is connected to the first input end of the first multiplier, the second input end of the first multiplier is connected to the output end of the second amplifier and the first input end of the second multiplier, the output end of the first multiplier is connected to the input end of the first integrator, the output end of the second multiplier is connected to the input end of the second integrator, and the value input to the input end of the second amplifier is the frequency of the AC harmonic signal at the output end of the battery; the voltage sampling module is used to sample the voltage at the output end of the battery and output the sampled voltage signal; the output end of the first integrator outputs the AC voltage signal.

[0024] Optionally, when the cosine signal and the sine signal are obtained by processing the sampled voltage signal based on the first SOGI module, the output end of the second subtractor outputs the cosine signal, and the output end of the first integrator outputs the sine signal.

[0025] Optionally, the second SOGI module includes: a third subtractor, a fourth subtractor, a third amplifier, a fourth amplifier, a third multiplier, a fourth multiplier, a third integrator and a fourth integrator; the first input end of the third subtractor is connected to the output end of the current sampling module, the second input end of the third subtractor is connected to the output end of the third integrator and the second input end of the fourth multiplier, the output end of the third subtractor is connected to the input end of the third amplifier, the output end of the third amplifier is connected to the first input end of the fourth subtractor, and the second input end of the fourth subtractor is connected to the output end of the fourth integrator. The output end of the fourth subtractor is connected to the first input end of the third multiplier, the second input end of the third multiplier is connected to the output end of the fourth amplifier and the first input end of the fourth multiplier, the output end of the third multiplier is connected to the input end of the third integrator, the output end of the fourth multiplier is connected to the input end of the fourth integrator, and the value input to the input end of the fourth amplifier is the frequency of the AC harmonic signal at the output end of the battery; the current sampling module is used to sample the current at the output end of the battery and output the sampled current signal; the output end of the third integrator outputs the AC current signal.

[0026] Optionally, when the cosine signal and the sine signal are obtained by processing the sampled current signal based on the second SOGI module, the output end of the fourth subtractor outputs the cosine signal, and the output end of the third integrator outputs the sine signal.

[0027] Optionally, the cosine signal and the sine signal have the same amplitude and a phase difference of 90 degrees.

[0028] A second aspect of an embodiment of the present application provides a measuring device, including: a voltage sampling module, a current sampling module, a first SOGI module, a second SOGI module, a signal processing module and a calculation module;

[0029] The voltage sampling module is used to obtain a sampled voltage signal at the output end of the battery;

[0030] The current sampling module is used to obtain a sampling current signal of the output end of the battery;

[0031] The first SOGI module is used to process the sampled voltage signal to obtain an AC voltage signal;

[0032] The second SOGI module is used to process the sampled current signal to obtain an AC current signal;

[0033] The signal processing module is used to obtain a first DC voltage signal based on the AC voltage signal and the cosine signal;

[0034] The signal processing module is further used to obtain a second DC voltage signal based on the AC voltage signal and the sine signal; the cosine signal and the sine signal are obtained by processing the sampled current signal based on the second SOGI module;

[0035] The signal processing module is further used to obtain a direct current signal based on the alternating current signal and the sinusoidal signal;

[0036] The calculation module is used to obtain the real impedance of the battery based on the first DC voltage signal and the DC current signal, and to obtain the imaginary impedance of the battery based on the second DC voltage signal and the DC current signal.

[0037] A third aspect of an embodiment of the present application provides a measuring device, including a processor and a memory, the memory being used to store a computer program, the computer program including program instructions, the processor being configured to call the program instructions and execute the step instructions in the first aspect of the embodiment of the present application.

[0038] The fourth aspect of an embodiment of the present application provides a computer-readable storage medium, wherein the above-mentioned computer-readable storage medium stores a computer program for electronic data exchange, and the computer program includes program instructions, and when the program instructions are executed by a processor, the processor executes the step instructions in the first aspect of the embodiment of the present application.

[0039] The fifth aspect of the embodiments of the present application provides a computer program product, wherein the above-mentioned computer program product includes a computer program, and the computer program includes program instructions, and when the program instructions are executed by a processor, the processor executes the step instructions in the first aspect of the embodiments of the present application.

[0040] In the embodiment of the present application, the sampled voltage signal and the sampled current signal of the output end of the battery are obtained; the sampled voltage signal is processed by the first SOGI module to obtain an AC voltage signal; the sampled current signal is processed by the second SOGI module to obtain an AC current signal; based on the AC voltage signal and the cosine signal, a first DC voltage signal is obtained; based on the AC voltage signal and the sine signal, a second DC voltage signal is obtained; the cosine signal and the sine signal are obtained by processing the sampled current signal based on the second SOGI module; based on the AC current signal and the sine signal, a DC current signal is obtained; the first DC voltage signal and the DC current signal are divided to obtain the real impedance of the battery, and the second DC voltage signal and the DC current signal are divided to obtain the imaginary impedance of the battery. In the embodiment of the present application, the AC impedance of the battery includes the real impedance and the imaginary impedance of the battery. In the process of calculating the AC impedance of the battery, only addition, subtraction, multiplication and division operations are needed, and there is no complex operation such as trigonometric function and square root. After obtaining the DC amount (the first DC voltage signal, the second DC voltage signal and the DC current signal), the calculation of the impedance does not need to be run during the interruption, which greatly reduces the time consumption of the interruption. There is no need for a large number of arrays to store data, and it has real-time performance. And it is an open-loop calculation, so there is no need to consider parameter adjustment and output signal interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 is a structural schematic diagram of a power supply system provided in an embodiment of the present application;

[0043] Figure 2 is a structural schematic diagram of a measuring device provided in an embodiment of the present application;

[0044] Figure 3 It is a flowchart of a method for measuring battery impedance provided by an embodiment of the present application;

[0045] Figure 4 This is a schematic diagram of a specific process of calculating battery impedance using a measuring device provided in an embodiment of the present application;

[0046] Figure 5 It is a structural diagram of a SOGI module provided in an embodiment of the present application. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0048] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, products or devices.

[0049] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0050] See also Figure 1 , Figure 1 Schematic diagram of a power supply system provided in an embodiment of the present application. Figure 1As shown, the power supply system includes a battery 10, a DC / DC converter 20 and a load 30. The power supply system also includes a measuring device 40, which can obtain a sampled voltage signal and a sampled current signal at the output end of the battery 10, and calculate the AC impedance of the battery 10 according to the sampled voltage signal and the sampled current signal at the output end of the battery 10. The AC impedance of the battery 10 includes a real impedance and an imaginary impedance. The measuring device 40 can also report the calculated AC impedance of the battery 10 to the control unit of the vehicle (for example, to the vehicle controller of the vehicle via CAN communication).

[0051] The battery 10 can supply power to the load 30 via the DC / DC converter 20. The battery 10 can be a fuel cell, such as a hydrogen fuel cell.

[0052] The DC / DC converter 20 is a direct current / direct current converter (DC / DC) converter. The DC / DC converter may also be called a DC-DC converter, which can convert one type of direct current into another type of direct current.

[0053] The load 30 may include a power battery or a low voltage load. The voltage of the power battery is generally above 100 V. The power battery can be used to power the motor on the electric vehicle. The power battery may be a lithium battery.

[0054] Low-voltage loads may include: navigation, audio and video, wipers, heaters, air conditioners, brakes, steering wheels, sensors, airbags, lighting systems (e.g., turn signals, tail lights, headlights, brake lights, vehicle interior lights, instrument panel lights, etc.), sound systems (e.g., radios, speakers, alarms) and other low-voltage loads (e.g., loads powered by 12V or 24V).

[0055] The measuring device 40 may be a component of a control chip, and the control chip may control the magnitude of the current output by the DC / DC converter 20 according to the sampled voltage signal and the sampled current signal at the output end of the battery 10 .

[0056] The AC impedance of the battery 10 reflects the state of the battery 10 more comprehensively than the DC impedance. It should be noted that when measuring the AC impedance of the battery 10, a DC / DC converter is required to generate an AC harmonic signal of a certain frequency at the output end of the battery 10. The frequency of the AC harmonic signal can be set as needed, for example, the frequency of the AC harmonic signal can be set to 1000 Hz. The AC harmonic signal can be an AC harmonic current.

[0057] In the embodiment of the present application, the measuring device 40 can sample the sampled voltage signal and the sampled current signal of the output end of the battery 10 in real time, and calculate the AC impedance of the battery 10 in real time, which greatly reduces the time consumption of interruption. There is no need to store data in a large array, and it has real-time performance. And it is an open-loop calculation, and there is no need to consider the interference of parameter adjustment and output signal.

[0058] See also Figure 2 , Figure 2 Schematic diagram of a measuring device provided in an embodiment of the present application. Figure 2 As shown, the measuring device 40 may include: a voltage sampling module 41, a current sampling module 42, a first SOGI module 43, a second SOGI module 44, a signal processing module 45 and a calculation module 46;

[0059] The voltage sampling module 41 is used to obtain a sampled voltage signal (such as Figure 2 Vsamp shown);

[0060] The current sampling module 42 is used to obtain a sampling current signal (such as Figure 2 Isamp shown);

[0061] The first SOGI module 43 is used to process the sampled voltage signal to obtain an AC voltage signal (such as Figure 2 Vsamp_ac as shown);

[0062] The second SOGI module 44 is used to process the sampled current signal to obtain an AC current signal (such as Figure 2 Isamp_ac shown);

[0063] The signal processing module 45 is used to process the AC voltage signal and the cosine signal (such as Figure 2 Xcos as shown), and obtain a first DC voltage signal (such as Figure 2 Vdc shown);

[0064] The signal processing module 45 is also used to process the AC voltage signal and the sinusoidal signal (such as Figure 2 Xsin as shown), and obtain a second DC voltage signal (such as Figure 2 The cosine signal and the sine signal are obtained by processing the sampled current signal based on the second SOGI module;

[0065] The signal processing module 45 is further configured to obtain a DC current signal (eg, Figure 2 Idc' shown);

[0066] The calculation module 46 is used to obtain the real impedance (such as Figure 2 Rr as shown), and for obtaining the imaginary impedance of the battery 10 (such as Figure 2 Ri shown).

[0067] In the embodiment of the present application, after an AC harmonic signal of a certain frequency is superimposed on the output end of the battery 10, the AC impedance of the battery 10 is measured. The AC harmonic signal can avoid the polarization effect in the process of measuring the impedance of the battery 10, thereby more accurately reflecting the real impedance characteristics of the battery 10. The measurement time of the AC harmonic signal is short (for example, about 100ms), which is suitable for all types of batteries 10, including small-capacity batteries 10, and causes less damage to the battery 10. The impedance characteristics of the battery 10 can be measured more accurately through the AC harmonic signal.

[0068] The voltage sampling module and the current sampling module can respectively and simultaneously obtain the sampled voltage signal and the sampled current signal of the output end of the battery 10. The signal processing module 45 can obtain the first DC voltage signal based on the AC voltage signal and the cosine signal, obtain the second DC voltage signal based on the AC voltage signal and the sine signal, and obtain the DC current signal based on the AC current signal and the sine signal. The calculation module 46 divides the first DC voltage signal and the DC current signal to obtain the real impedance of the battery 10, and divides the second DC voltage signal and the DC current signal to obtain the imaginary impedance of the battery 10.

[0069] In the embodiment of the present application, the AC impedance of the battery 10 includes the real impedance and the imaginary impedance of the battery 10. In the process of calculating the AC impedance of the battery 10, only addition, subtraction, multiplication and division operations are needed, and no complex operations such as trigonometric functions and square root extraction are involved. After obtaining the DC quantity (the first DC voltage signal, the second DC voltage signal and the DC current signal), the calculation of the impedance does not need to be run during the interruption, which greatly reduces the time consumption of the interruption. There is no need for a large number of arrays to store data, and it has real-time performance. And it is an open-loop calculation, and there is no need to consider the interference of parameter adjustment and output signals.

[0070] See also Figure 3 , Figure 3 FIG. 1 is a flow chart of a method for measuring battery impedance provided by an embodiment of the present application. Figure 3 As shown, the method may include the following steps.

[0071] 301. A measuring device obtains a sampled voltage signal and a sampled current signal at an output end of a battery.

[0072] In the embodiment of the present application, the measuring device can obtain the sampled voltage signal of the output end of the battery through the voltage sampling module, and obtain the sampled current signal of the output end of the battery through the current sampling module. After superimposing an AC harmonic signal of a certain frequency on the output end of the battery, the voltage sampling module and the current sampling module can respectively and simultaneously obtain the sampled voltage signal and the sampled current signal of the output end of the battery.

[0073] The sampled voltage signal includes a DC signal of the voltage at the output end of the battery and a superposition signal of the AC signal. The sampled current signal includes a DC signal of the current at the output end of the battery and a superposition signal of the AC signal.

[0074] For example, Figure 2 As shown, the sampled voltage signal is Vsamp, and the sampled current signal is Isamp.

[0075] 302. The measuring device processes the sampled voltage signal through a first SOGI module to obtain an AC voltage signal.

[0076] The second-order generalized integrator (SOGI) module has the function of separating AC and DC superimposed signals, thus obtaining the AC component of the original signal.

[0077] The first SOGI module performs AC / DC separation on the sampled voltage signal to obtain an AC voltage signal of a specified frequency. The frequency of the AC voltage signal is the same as the frequency of the AC harmonic signal.

[0078] For example, Figure 2 As shown, the AC voltage signal is Vsamp_ac.

[0079] 303 , the measuring device processes the sampled current signal through the second SOGI module to obtain an AC current signal.

[0080] The second SOGI module performs AC / DC separation on the sampled current signal to obtain an AC current signal of a specified frequency. The frequency of the AC current signal is the same as the frequency of the AC harmonic signal.

[0081] For example, Figure 2 As shown, the AC current signal is Isamp_ac.

[0082] 304. The measuring device obtains a first DC voltage signal based on the AC voltage signal and the cosine signal.

[0083] For example, Figure 2 As shown, the cosine signal is Xcos.

[0084] 305. The measuring device obtains a second DC voltage signal based on the AC voltage signal and the sinusoidal signal.

[0085] The cosine signal and the sine signal are obtained by processing the sampled current signal based on the second SOGI module.

[0086] For example, Figure 2 As shown, the sinusoidal signal is Xsin.

[0087] Optionally, the cosine signal and the sine signal have the same amplitude and a phase difference of 90 degrees.

[0088] The cosine signal and the sine signal have the same amplitude and a phase difference of 90 degrees (°), so that the first DC voltage signal and the second DC voltage signal have the same amplitude and a phase difference of 90°. Since the phase difference between the real impedance and the imaginary impedance is 90°, the first DC voltage signal and the second DC voltage signal have the same amplitude and a phase difference of 90°, which can facilitate the subsequent calculation of the real impedance and the imaginary impedance according to the first DC voltage signal and the second DC voltage signal.

[0089] The AC current signal and the cosine signal have the same amplitude and a 90° phase difference, and the AC current signal and the sine signal have the same amplitude and the same phase.

[0090] 306 , the measuring device obtains a direct current signal based on the alternating current signal and the sinusoidal signal.

[0091] In the embodiment of the present application, the AC current signal and the sinusoidal signal have the same amplitude and phase, and the DC current signal obtained based on the AC current signal and the sinusoidal signal has amplitude but no phase information.

[0092] For example, Figure 2 As shown, the first DC voltage signal is Vdc, the second DC voltage signal is Vdc', and the DC current signal is Idc'.

[0093] 307 , the measuring device divides the first DC voltage signal and the DC current signal to obtain the real impedance of the battery, and divides the second DC voltage signal and the DC current signal to obtain the imaginary impedance of the battery.

[0094] In the embodiment of the present application, the first DC voltage signal is divided by the DC current signal to obtain the real impedance of the battery, and the second DC voltage signal is divided by the DC current signal to obtain the imaginary impedance of the battery.

[0095] In the embodiment of the present application, the AC impedance of the battery includes the real impedance and imaginary impedance of the battery. In the process of calculating the AC impedance of the battery, only addition, subtraction, multiplication and division operations are needed, and no complex operations such as trigonometric functions and square root extraction are involved. After obtaining the DC quantity (first DC voltage signal, second DC voltage signal and DC current signal), the calculation of the impedance does not need to be run during the interruption, which greatly reduces the time consumption of the interruption. There is no need for a large number of arrays to store data, and it has real-time performance. And it is an open-loop calculation, and there is no need to consider the interference of parameter adjustment and output signals.

[0096] Optionally, step 304 may specifically include the following steps:

[0097] The measuring device performs multiplication operation on the AC voltage signal and the cosine signal to obtain a first superimposed voltage signal; the measuring device performs filtering processing on the first superimposed voltage signal to obtain a first DC voltage signal.

[0098] Optionally, step 305 may specifically include the following steps:

[0099] The measuring device performs multiplication operation on the AC voltage signal and the sinusoidal signal to obtain a second superimposed voltage signal; the measuring device performs filtering processing on the second superimposed voltage signal to obtain a second DC voltage signal.

[0100] Optionally, step 306 may specifically include the following steps:

[0101] The measuring device performs multiplication operation on the AC current signal and the sinusoidal signal to obtain a superimposed current signal; the measuring device performs filtering processing on the superimposed current signal to obtain a DC current signal.

[0102] See also Figure 4 , Figure 4 1 is a schematic diagram of a specific process of calculating battery impedance using a measuring device provided in an embodiment of the present application. Figure 4As shown, the voltage sampling module 41 obtains the sampled voltage signal Vsamp at the output end of the battery, and the current sampling module 42 obtains the sampled current signal Isamp at the output end of the battery. The first SOGI module 43 processes the sampled voltage signal Vsamp to obtain the AC voltage signal Vsamp_ac. The second SOGI module 44 processes the sampled current signal Isamp to obtain the AC current signal Isamp_ac, the cosine signal Xcos and the sine signal Xsin. The signal processing module 45 multiplies the AC voltage signal Vsamp_ac and the cosine signal Xcos to obtain a first superimposed voltage signal, namely Vdc (DC signal) + Vac (AC signal). The signal processing module 45 multiplies the AC voltage signal Vsamp_ac and the sine signal Xsin to obtain a second superimposed voltage signal, namely Vdc' (DC signal) + Vac' (AC signal). The signal processing module 45 multiplies the AC current signal Isamp_ac and the sinusoidal signal Xsin to obtain a superimposed current signal, i.e., Idc' (DC signal) + Iac' (AC signal). The first notch filter filters out the AC signal in the first superimposed voltage signal to obtain the first DC voltage signal Vdc. The second notch filter filters out the AC signal in the second superimposed voltage signal to obtain the second DC voltage signal Vdc'. The third notch filter filters out the AC signal in the superimposed current signal to obtain the DC current signal Idc'. The calculation module 46 divides the first DC voltage signal Vdc by the DC current signal Idc' to obtain the real impedance Rr of the battery, and divides the second DC voltage signal Vdc' by the DC current signal Idc' to obtain the imaginary impedance Ri of the battery. The impedance Rz of the battery 10 is Rr+i*Ri.

[0103] Exemplarily, if Vsamp_ac=A*sin(wt+a), Isamp_ac=B*sin(wt+b), Xcos=B*cos(wt+b), Xsin=B*sin(wt+b). Then the first superimposed voltage signal=Vsamp_ac*Xcos=A*sin(wt+a)*B*cos(wt+b). The second superimposed signal=Vsamp_ac*Xcos=A*sin(wt+a)*B*sin(wt+b). The superimposed current signal=B*sin(wt+b)*B*sin(wt+b). Wherein, w=2π*f0, where f0 is the frequency of the AC harmonic signal superimposed on the output end of the battery. “*” represents multiplication.

[0104] It can be seen that the first superimposed voltage signal includes Vdc (DC signal) + Vac (AC signal), wherein the frequency of Vac is twice the frequency of Vsamp_ac, and the first notch filter can filter out Vac in the first superimposed voltage signal, thereby outputting Vdc. The second superimposed voltage signal includes Vdc' (DC signal) + Vac' (AC signal), wherein the frequency of Vac' is twice the frequency of Vsamp_ac, and the second notch filter can filter out Vac' in the second superimposed voltage signal, thereby outputting Vdc'. The superimposed current signal includes Idc' (DC signal) + Iac' (AC signal), wherein Iac' is twice the frequency of Isamp_ac, and the second notch filter can filter out Iac' in the superimposed current signal, thereby outputting Idc'.

[0105] Vdc = A*B*sin(ab) / 2;

[0106] Vdc'=A*B*cos(ab) / 2;

[0107] Idc'=B 2 / 2;

[0108] Rr=Vdc / Idc'=A*cos(ab) / B;

[0109] Ri=Vdc' / Idc'=A*sin(ab) / B.

[0110] In the embodiment of the present application, the function of the SOGI module is utilized, and the relationship between the output signals of the SOGI module is combined, and the AC impedance of the battery can be obtained by using a notch filter and simple operations (addition, subtraction, multiplication and division operations). The AC impedance of the battery can be obtained in real time without complex operations and a large amount of storage depth.

[0111] Optionally, the first SOGI module includes: a first subtractor, a second subtractor, a first amplifier, a second amplifier, a first multiplier, a second multiplier, a first integrator and a second integrator; the first input end of the first subtractor is connected to the output end of the voltage sampling module, the second input end of the first subtractor is connected to the output end of the first integrator and the second input end of the second multiplier, the output end of the first subtractor is connected to the input end of the first amplifier, the output end of the first amplifier is connected to the first input end of the second subtractor, the second input end of the second subtractor is connected to the output end of the second integrator, the output end of the second subtractor is connected to the first input end of the first multiplier, the second input end of the first multiplier is connected to the output end of the second amplifier and the first input end of the second multiplier, the output end of the first multiplier is connected to the input end of the first integrator, the output end of the second multiplier is connected to the input end of the second integrator, and the value input to the input end of the second amplifier is the frequency of the AC harmonic signal at the output end of the battery; the voltage sampling module is used to sample the voltage at the output end of the battery and output the sampled voltage signal; the output end of the first integrator outputs the AC voltage signal.

[0112] Wherein, when the cosine signal and the sine signal are obtained by processing the sampled voltage signal based on the first SOGI module, the output end of the second subtractor outputs the cosine signal, and the output end of the first integrator outputs the sine signal.

[0113] Optionally, the second SOGI module includes: a third subtractor, a fourth subtractor, a third amplifier, a fourth amplifier, a third multiplier, a fourth multiplier, a third integrator and a fourth integrator; the first input end of the third subtractor is connected to the output end of the current sampling module, the second input end of the third subtractor is connected to the output end of the third integrator and the second input end of the fourth multiplier, the output end of the third subtractor is connected to the input end of the third amplifier, the output end of the third amplifier is connected to the first input end of the fourth subtractor, and the second input end of the fourth subtractor is connected to the output end of the fourth integrator. The output end of the fourth subtractor is connected to the first input end of the third multiplier, the second input end of the third multiplier is connected to the output end of the fourth amplifier and the first input end of the fourth multiplier, the output end of the third multiplier is connected to the input end of the third integrator, the output end of the fourth multiplier is connected to the input end of the fourth integrator, and the value input to the input end of the fourth amplifier is the frequency of the AC harmonic signal at the output end of the battery; the current sampling module is used to sample the current at the output end of the battery and output the sampled current signal; the output end of the third integrator outputs the AC current signal.

[0114] Wherein, when the cosine signal and the sine signal are obtained by processing the sampled current signal based on the second SOGI module, the output end of the fourth subtractor outputs the cosine signal, and the output end of the third integrator outputs the sine signal.

[0115] See also Figure 5 , Figure 5 It is a structural schematic diagram of a SOGI module provided in an embodiment of the present application. The SOGI module includes two subtractors: subtractor 1 (corresponding to the above-mentioned first subtractor or third subtractor) and subtractor 2 (corresponding to the above-mentioned second subtractor or fourth subtractor), two amplifiers: amplifier 1 (corresponding to the above-mentioned first amplifier or third amplifier) ​​and amplifier 2 (corresponding to the above-mentioned second amplifier and fourth amplifier), two multipliers: multiplier 1 (corresponding to the above-mentioned first multiplier or third multiplier) and multiplier 2 (corresponding to the above-mentioned second multiplier or fourth multiplier), and two integrators: integrator 1 (corresponding to the above-mentioned first integrator or third integrator) and integrator 2 (corresponding to the above-mentioned second integrator or fourth integrator). Among them, k1 in amplifier 1 represents the first amplification factor, and k2 in amplifier 2 represents the second amplification factor. k1 can be selected as needed, and k1 can select a constant less than 1. For example, k1 can be taken as 0.4. k2 can be set to 2π, so that the output of amplifier 2 is 2π*f0. The first input terminal of the subtractor 1 inputs Vsamp or Isamp, and the output of the integrator 1 is Vsamp_ac or Isamp_ac. When Vsamp is input to the first input terminal of the subtractor 1, the output of the integrator 1 is Vsamp_ac; when Isamp is input to the first input terminal of the subtractor 1, the output of the integrator 1 is Isamp_ac.

[0116] In the embodiment of the present application, the AC impedance of the battery includes the real impedance and imaginary impedance of the battery. In the process of calculating the AC impedance of the battery, only addition, subtraction, multiplication and division operations are needed, and no complex operations such as trigonometric functions and square root extraction are involved. After obtaining the DC quantity (the first DC voltage signal, the second DC voltage signal and the DC current signal), the calculation of the impedance does not need to be run during the interruption, which greatly reduces the time consumption of the interruption. There is no need for a large number of arrays to store data, and it has real-time performance. And it is an open-loop calculation, and there is no need to consider the interference of parameter adjustment and output signals.

[0117] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0118] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0119] In the several embodiments provided in the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of the units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the device or unit can be electrical or other forms.

[0120] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0121] In addition, the functional units in the various embodiments of the application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated units may be implemented in the form of hardware or in the form of software program modules.

[0122] If the integrated unit is implemented in the form of a software program module and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a memory, including a number of instructions to enable a computer device (which can be a personal computer, a measuring device or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned memory includes: U disk, read-only memory (ROM), random access memory (RAM), mobile hard disk, disk or optical disk and other media that can store program codes.

[0123] A person of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable memory, which can include: a flash drive, a read-only memory, a random access memory, a magnetic disk or an optical disk, etc.

[0124] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for measuring battery impedance, characterized in that: include: Acquire a sampled voltage signal and a sampled current signal at the output end of the battery; The sampled voltage signal is processed by a first generalized second-order integrator SOGI module to obtain an AC voltage signal; Processing the sampled current signal through a second SOGI module to obtain an alternating current signal; Based on the AC voltage signal and the cosine signal, a first DC voltage signal is obtained; Based on the AC voltage signal and the sine signal, a second DC voltage signal is obtained; the cosine signal and the sine signal are obtained by processing the sampled current signal based on the second SOGI module; Obtaining a direct current signal based on the alternating current signal and the sinusoidal signal; The first DC voltage signal and the DC current signal are divided to obtain the real impedance of the battery, and the second DC voltage signal and the DC current signal are divided to obtain the imaginary impedance of the battery.

2. The method according to claim 1, characterized in that The step of obtaining a first DC voltage signal based on the AC voltage signal and the cosine signal comprises: Multiplying the AC voltage signal and the cosine signal to obtain a first superimposed voltage signal; The first superimposed voltage signal is filtered to obtain a first direct current voltage signal.

3. The method according to claim 1, characterized in that The step of obtaining a second DC voltage signal based on the AC voltage signal and the sinusoidal signal comprises: Multiplying the AC voltage signal and the sinusoidal signal to obtain a second superimposed voltage signal; The second superimposed voltage signal is filtered to obtain a second DC voltage signal.

4. The method according to claim 1, characterized in that: The step of obtaining a direct current signal based on the alternating current signal and the sinusoidal signal comprises: Multiplying the alternating current signal and the sinusoidal signal to obtain a superimposed current signal; The superimposed current signal is filtered to obtain a direct current signal.

5. The method according to any one of claims 1 to 4, characterized in that: The first SOGI module includes: a first subtractor, a second subtractor, a first amplifier, a second amplifier, a first multiplier, a second multiplier, a first integrator and a second integrator; the first input end of the first subtractor is connected to the output end of the voltage sampling module, the second input end of the first subtractor is connected to the output end of the first integrator and the second input end of the second multiplier, the output end of the first subtractor is connected to the input end of the first amplifier, the output end of the first amplifier is connected to the first input end of the second subtractor, the second input end of the second subtractor is connected to the output end of the second integrator, the output end of the second subtractor is connected to the first input end of the first multiplier, the second input end of the first multiplier is connected to the output end of the second amplifier and the first input end of the second multiplier, the output end of the first multiplier is connected to the input end of the first integrator, the output end of the second multiplier is connected to the input end of the second integrator, and the value input to the input end of the second amplifier is the frequency of the AC harmonic signal at the output end of the battery; the voltage sampling module is used to sample the voltage at the output end of the battery and output the sampled voltage signal; the output end of the first integrator outputs the AC voltage signal.

6. The method according to claim 5, characterized in that When the cosine signal and the sine signal are obtained by processing the sampled voltage signal based on the first SOGI module, the output end of the second subtractor outputs the cosine signal, and the output end of the first integrator outputs the sine signal.

7. The method according to any one of claims 1 to 4, characterized in that: The second SOGI module includes: a third subtractor, a fourth subtractor, a third amplifier, a fourth amplifier, a third multiplier, a fourth multiplier, a third integrator and a fourth integrator; the first input end of the third subtractor is connected to the output end of the current sampling module, the second input end of the third subtractor is connected to the output end of the third integrator and the second input end of the fourth multiplier, the output end of the third subtractor is connected to the input end of the third amplifier, the output end of the third amplifier is connected to the first input end of the fourth subtractor, and the second input end of the fourth subtractor is connected to the output end of the fourth integrator. The output end of the fourth subtractor is connected to the first input end of the third multiplier, the second input end of the third multiplier is connected to the output end of the fourth amplifier and the first input end of the fourth multiplier, the output end of the third multiplier is connected to the input end of the third integrator, the output end of the fourth multiplier is connected to the input end of the fourth integrator, and the value input to the input end of the fourth amplifier is the frequency of the AC harmonic signal at the output end of the battery; the current sampling module is used to sample the current at the output end of the battery and output the sampled current signal; the output end of the third integrator outputs the AC current signal.

8. The method according to claim 7, characterized in that When the cosine signal and the sine signal are obtained by processing the sampled current signal based on the second SOGI module, the output end of the fourth subtractor outputs the cosine signal, and the output end of the third integrator outputs the sine signal.

9. The method according to any one of claims 1 to 4, characterized in that: The cosine signal and the sine signal have the same amplitude and a phase difference of 90 degrees.

10. A measuring device, characterized in that: include: A voltage sampling module, a current sampling module, a first SOGI module, a second SOGI module, a signal processing module and a calculation module; The voltage sampling module is used to obtain a sampled voltage signal at the output end of the battery; The current sampling module is used to obtain a sampling current signal of the output end of the battery; The first SOGI module is used to process the sampled voltage signal to obtain an AC voltage signal; The second SOGI module is used to process the sampled current signal to obtain an AC current signal; The signal processing module is used to obtain a first DC voltage signal based on the AC voltage signal and the cosine signal; The signal processing module is further used to obtain a second DC voltage signal based on the AC voltage signal and the sine signal; the cosine signal and the sine signal are obtained by processing the sampled current signal based on the second SOGI module; The signal processing module is further used to obtain a direct current signal based on the alternating current signal and the sinusoidal signal; The calculation module is used to obtain the real impedance of the battery based on the first DC voltage signal and the DC current signal, and to obtain the imaginary impedance of the battery based on the second DC voltage signal and the DC current signal.

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