JP2023108903A - Processor and calculation system - Google Patents

Abstract

To acquire a high-frequency signal of a battery signal without increasing a sampling frequency.SOLUTION: A processing section 30 comprises a first filter section 101, a generation section 113, a first multiplication section 111, a second filter section 102, and a communication section 114. The first filter section 101 generates a first signal by extracting a signal of a first frequency component from a voltage signal of a battery. The first multiplication section 111 generates a first multiplication signal by multiplying a first sine wave signal generated by the generation section 113 by the first signal. The second filter section 102 generates a second signal by extracting a signal of a second frequency component from the first multiplication signal. The communication section 114 samples the second signal with a first sampling frequency. The first signal includes a signal of a first specific frequency larger than 1/2 of the first sampling frequency. The second signal includes a signal of a frequency smaller than the first specific frequency.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to processing devices and computing systems.

For example, Japanese Patent Laying-Open No. 2021-12065 (Patent Document 1) discloses a battery monitoring device that calculates the impedance of a battery. This battery monitoring device acquires a digital signal of voltage or current by sampling at a predetermined sampling frequency in order to calculate the impedance of the battery.

Japanese Patent Application Laid-Open No. 2021-12065

When acquiring a high-frequency signal of a battery signal that is at least one of a current signal and a voltage signal, sampling processing is performed on the battery signal while components with frequencies equal to or higher than 1/2 of the sampling frequency remain. Then aliasing effects occur. Therefore, it is conceivable to increase the sampling frequency so as not to cause the influence of aliasing. However, increasing the sampling frequency causes problems such as an increase in the cost of the apparatus.

The present disclosure has been made to solve the above-described problems, and its object is to acquire a high-frequency signal of a battery signal without increasing the sampling frequency.

A processing apparatus according to the present disclosure includes a first filter unit, a generator, a first multiplier, a second filter unit, and a first sampler. The first filter unit generates a first signal by extracting a signal of a first frequency component from a battery signal that is at least one of a current signal charged/discharged to a chargeable/dischargeable battery and a voltage signal of the battery. do. The generator generates a first sine wave signal. The first multiplier generates a first multiplied signal by multiplying the first signal by the first sine wave signal. The second filter section generates a second signal by extracting a signal of a second frequency component from the first multiplied signal. The first sampling section samples the second signal at a first sampling frequency. The first signal includes a signal at a first specific frequency greater than half the first sampling frequency. The second signal includes signals with frequencies less than the first specific frequency.

According to the present disclosure, a high frequency signal of a battery signal can be acquired without increasing the sampling frequency.

It is a figure showing typically an example of composition of vehicles of this embodiment. 4 is a functional block diagram of a BMU; FIG. It is a functional block diagram of a processing unit of a comparative example. FIG. 5 is a diagram showing signals and the like generated by a processing unit of a comparative example; It is a figure which shows the structural example of the process part of this Embodiment. It is a figure for demonstrating the principle of the process part of this Embodiment. It is a figure for demonstrating the principle of the process part of this Embodiment. It is a figure for demonstrating the principle of the process part of this Embodiment. 3 is a functional block diagram of an impedance calculator; FIG. It is an example of an impedance plot. 4 is a flowchart showing BMU processing. It is a configuration example of a processing unit of a modified example. It is a figure for demonstrating the principle of the process part of a modification.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

[Vehicle configuration]
FIG. 1 is a diagram schematically showing an example of the configuration of a vehicle 1 equipped with a state calculation device according to this embodiment. The vehicle 1 includes driving wheels 2, a motor generator 3 mechanically connected to the driving wheels 2, a power control unit (PCU) 4, a battery 5, and an electronic control unit (ECU). ) 6 and a battery monitoring device (BMU: Battery Management Unit) 100 . The BMU 100 corresponds to the "calculation system" of the present disclosure.

Vehicle 1 is an electric vehicle that runs using the power of motor generator 3 . Vehicle 1 may be provided with a power source (for example, an engine) other than motor generator 3 .

Motor generator 3 is, for example, a three-phase AC rotating electric machine. Motor generator 3 is driven by electric power supplied from battery 5 via PCU 4 . Also, the motor generator 3 can regenerate power using the power transmitted from the driving wheels 2 and supply the generated power to the battery 5 via the PCU 4 .

The battery 5 includes a secondary battery (chargeable/dischargeable battery) such as a lithium ion battery or a nickel hydrogen battery. The secondary battery may be a single battery or an assembled battery.

PCU 4 includes an inverter 41 and a step-up/step-down converter that operate according to instructions from ECU 6 . The PCU 4 converts electric power supplied from the battery 5 into electric power capable of driving the motor generator 3 and supplies the electric power to the motor generator 3 according to an instruction from the ECU 6 . Further, the PCU 4 converts the electric power generated by the motor generator 3 into electric power capable of charging the battery 5 and supplies the electric power to the battery 5 .

Although not shown, the vehicle 1 is provided with a plurality of sensors for detecting various physical quantities necessary for controlling the vehicle 1, such as the driver's accelerator pedal operation amount, brake pedal operation amount, and vehicle speed. . These sensors transmit detection results to the ECU 6 .

BMU 100 detects voltage, current, and temperature of battery 5 . The BMU 100 also has a function of calculating the impedance and resistance deterioration degree of the battery 5, as will be described later. BMU100 outputs a calculation result and a detection result to ECU6.

BMU 100 has processor 181 , memory 182 , and communication I/F 183 . The processor 181 is configured to execute predetermined arithmetic processing. The memory 182 is composed of a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The ROM stores programs executed by the processor 181 . The RAM temporarily stores data generated by executing programs in the processor 181 . RAM can function as a temporary data memory that is used as a working area. Communication I/F 183 is configured to communicate with an external device (ECU 100, etc.).

The ECU 6 executes predetermined arithmetic processing based on information from each sensor and the BMU 100 and information stored in the memory, and controls the PCU 4 based on the arithmetic results.

FIG. 2 is a functional block diagram of BMU 100. As shown in FIG. BMU 100 includes measuring section 15 , current measuring section 10 , voltage measuring section 20 , processing section 30 , impedance calculating section 50 , deterioration degree calculating section 80 , and reference impedance storage section 70 . The measuring section 15 has a current measuring section 10 and a voltage measuring section 20 . The current measurement unit 10 corresponds to the "first measurement unit", the voltage measurement unit 20 corresponds to the "second measurement unit", the impedance calculation unit 50 corresponds to the "first calculation unit", and the deterioration degree calculation The unit 80 corresponds to the "second calculator", and the reference impedance storage unit 70 corresponds to the "storage unit". Also, the processing unit 30 corresponds to the “processing device” of the present disclosure.

Also, the processing unit 30 and the impedance calculation unit 50 have different reference potentials. Therefore, it is difficult for the processing unit 30 and the impedance calculation unit 50 to directly transmit and receive signals. In this embodiment, the processing unit 30 and the impedance calculation unit 50 transmit and receive signals by insulated communication. Each of processing unit 30 and impedance calculation unit 50 has processor 181 , memory 182 , and communication I/F 183 described above.

The current measurement unit 10 measures the current charged/discharged in the battery 5 and outputs the current to the processing unit 30 . “Current charged/discharged in the battery 5” indicates current charged in the battery 5 or current discharged from the battery 5. FIG. Voltage measurement unit 20 measures the voltage of battery 5 during current measurement by current measurement unit 10 and outputs the voltage to processing unit 30 .

[Comparative example]
FIG. 3 is a diagram for explaining a configuration of a processing unit of a comparative example; In the example of FIG. 3, it has a measurement unit 86, an LPF (Low Pass Filter) 81, an analog-to-digital conversion unit (hereinafter also referred to as “ADC 82”), an LPF 83, and a communication unit 84. . In the example of FIG. 3, the measurement unit 86 measures the battery 5 and outputs a voltage signal. Communication unit 84 outputs to calculation unit 85 a signal obtained by subjecting the voltage signal to predetermined processing by LPF 81 , ADC 82 , and LPF 83 .

In the example of FIG. 3, the ADC 82 converts the analog signal input to the ADC 82 into a digital signal by sampling the analog signal at the sampling frequency fs1. Further, the communication unit 84 samples the digital signal input to the communication unit 84 at the sampling frequency fs<b>2 and outputs the sampled signal to the calculation unit 85 . Also, in the example of FIG. 3, fs1>fs2.

Here, the Nyquist frequency of the sampling frequency fs1 of the ADC 82 is (fs1)/2, and the Nyquist frequency of the sampling frequency fs2 of the communication unit 84 is (fs2)/2.

Generally, in the sampling process, aliasing effects occur when frequencies exceeding the Nyquist frequency are sampled. For example, the case where the frequency of the signal before sampling by the ADC 82 is 11 Hz and the sampling frequency is 10 Hz will be described. In this case, since the Nyquist frequency is 5 Hz, 11 Hz>5 Hz. Then, although the signal is actually 11 Hz, the effect of aliasing is that the signal is converted into a signal of 1 Hz.

Therefore, it is conceivable to increase the sampling frequency. For example, in the above example, it is conceivable to set the sampling frequency to 22 Hz or higher. However, when the sampling frequency is increased in this way, there arises a problem that the cost of sampling processing increases.

In the example of FIG. 3, LPF81 and LPF82 are placed before the sampling process to reduce such aliasing. LPF81 and LPF82 are anti-aliasing filters.

The LPF 81 removes signals of frequency components (high frequency components) of (fs1)/2 or higher. The LPF 83 also removes signals of frequency components (high frequency components) of (fs2)/2 or higher. In this way, high frequency component signals are removed.

FIG. 4 is a diagram showing the removed signal. The horizontal axis in FIG. 4 indicates frequency. As shown in FIG. 4, in the processing unit of the comparative example, frequency components (high frequency components) of (fs1)/2 or higher are removed in order to remove aliasing. Therefore, the communication unit 84 outputs the voltage signal from which the high frequency component has been removed to the impedance calculation unit, so that the impedance cannot be calculated accurately. Although not shown in FIGS. 3 and 4, the measuring section 86 also measures the current signal. For the same reason as described above, the processing unit of the comparative example outputs the voltage signal from which the high frequency component has been removed to the impedance calculation unit.

Therefore, the processing unit 30 of the present embodiment is configured to suppress the influence of aliasing, to compensate for the removed high-frequency component signal without increasing the sampling frequency.

[Configuration of processing unit]
FIG. 5 is a diagram showing a configuration example of the processing unit 30. As shown in FIG. In the following description, "greater than X" may be replaced with "greater than or equal to X." Also, "less than X" may be replaced with "less than X."

The processing unit 30 has an analog circuit 120 , an ADC 109 , an ADC 110 , an integrated circuit 122 and a generation unit 113 . The integrated circuit 122 is configured by, for example, an ASIC (application specific integrated circuit).

The analog circuit 120 has a seventh filter section 107 that is an LPF and an eighth filter section 108 that is an LPF. Both the seventh filter section 107 and the eighth filter section 108 are configured by analog circuits.

The integrated circuit 122 includes a first filter section 101 that is a BPF (Band Pass Filter), a second filter section 102 that is an LPF, a third filter section 103 that is a BPF, and a fourth filter that is an LPF. It has functions of section 104 , fifth filter section 105 as LPF, sixth filter section 106 as LPF, first multiplication section 111 , second multiplication section 112 , and generation section 113 .

Further, the LPF (second filter section 102, fourth filter section 104, fifth filter section 105, sixth filter section 106, seventh filter section 107, eighth filter section 108) shown in FIG. is.

Also, the voltage signal ADC 109 samples the voltage signal at the sampling frequency fs1. The current signal ADC 110 samples the current signal at a sampling frequency fs1. The sampling frequencies of ADC 109 and ADC 110 are the same. Also, the communication unit 114 samples the signal input to the communication unit 114 at the sampling frequency fs2. The sampling frequency fs2 corresponds to the communication cycle of the communication unit 114. FIG. Also, the communication unit 114 corresponds to the “first sampling unit” and the “second sampling unit” of the present disclosure. Also, the sampling frequency fs2 corresponds to the "first sampling frequency" and the "second sampling frequency" of the present disclosure. The "first sampling section" and the "second sampling section" may have different configurations.

First, the flow of voltage signals will be described. A voltage signal measured by the voltage measurement unit 20 is input to the seventh filter unit 107 . A seventh filter unit 107 generates a seventh signal by extracting the signal of the seventh frequency component. A seventh signal is an analog signal. The seventh frequency component is a frequency component less than (fs1)/2. That is, the seventh signal is a voltage signal from which frequency components above (fs1)/2 have been removed. A seventh signal is input to the ADC 109 . The seventh signal is sampled by the ADC 109 at the sampling frequency fs1.

A voltage signal sampled by ADC 109 is input to first filter section 101 and fifth filter section 105 . The sampled signal corresponds to the "battery signal" of this disclosure.

The first filter section 101 generates a first signal by extracting a signal of a first frequency component from the sampled signal. Here, the first frequency component is a frequency band greater than (fs2)/2 and less than (fs1)/2. The first signal is input to first multiplier 111 . In addition, generation section 113 generates a sine wave signal and outputs the sine wave signal to first multiplication section 111 and second multiplication section 112 . In this embodiment, the same sine wave signal is input to the first multiplier 111 and the second multiplier 112 . The same sinusoidal signal corresponds to the first sinusoidal signal and the second sinusoidal signal of the present disclosure. As a modification, the first sine wave signal and the second sine wave signal may be different.

The first multiplier 111 generates a first multiplied signal by multiplying the first signal by a sine wave signal (first sine wave signal). The first multiplied signal is output to second filter section 102 . A second filter section 102 generates a second signal by extracting a signal of a second frequency component from the first multiplied signal. Here, the second frequency component is a frequency component less than (fs2)/2. That is, the second signal is a voltage signal from which frequency components of (fs2)/2 or higher have been removed. The second signal is input to communication section 114 . Also, as will be described later, the second signal is a high-frequency voltage signal VH.

Fifth filter section 105 also generates a fifth signal by extracting the signal of the fifth frequency component from the signal from ADC 109 . The fifth signal is input to communication section 114 . Also, as will be described later, the fifth signal is a low-frequency voltage signal VL. The frequency of the fifth frequency component and the frequency of a sixth frequency component described later are smaller than (fs2)/2.

Next, the flow of current signals will be described. A current signal measured by the current measurement unit 10 is input to the eighth filter unit 108 . The eighth filter section 108 generates an eighth signal by extracting the signal of the eighth frequency component. The eighth frequency component is a frequency component less than (fs1)/2. That is, the eighth signal is a current signal from which frequency components of (fs1)/2 or higher have been removed. The eighth signal is input to ADC 110 . The eighth signal is sampled by ADC 110 at sampling frequency fs1.

A current signal sampled by ADC 110 is input to third filter section 103 and sixth filter section 106 . The sampled current signal corresponds to the "battery signal" of this disclosure.

A third filter section 103 generates a third signal by extracting a signal of a third frequency component from the sampled signal. Here, the third frequency component is a frequency band greater than (fs2)/2 and less than (fs1)/2. The third signal is input to second multiplier 112 .

The second multiplier 112 generates a second multiplied signal by multiplying the third signal by a sine wave signal (second sine wave signal). The second multiplied signal is output to fourth filter section 104 . A fourth filter section 104 generates a fourth signal by extracting a signal of a fourth frequency component from the second multiplied signal. Here, the fourth frequency component is a frequency component less than (fs2)/2. That is, the fourth signal is a current signal from which frequency components above (fs2)/2 have been removed. The fourth signal is input to communication section 114 . Also, as will be described later, the fourth signal is a current high-frequency signal IH.

Also, the sixth filter unit 106 extracts the signal of the sixth frequency component from the signal from the ADC 110 to generate the sixth signal. The sixth signal is input to communication section 114 . Also, as will be described later, the sixth signal is a low-frequency current signal IL.

The communication unit samples the second signal, the fourth signal, the fifth signal, and the sixth signal at the sampling frequency fs2, and outputs the sampled signals to the impedance calculation unit 50.

[principle]
Next, the principle that the processing unit 30 can compensate for the removed high-frequency component signal without increasing the sampling frequency will be described. FIG. 6 is a diagram for explaining this principle. In FIGS. 6A, 6B, and 6C, the horizontal axis indicates frequency, and the vertical axis indicates intensity. 6A to 6C show signal components extracted by the first filter section 101, the first multiplication section 111, and the second filter section 102, respectively.

FIG. 6A shows the component 201 of the first signal and the component 202 of the sinusoidal signal of frequency fLo. Here, the component 201 of the first signal is the component extracted by the first filter section 101 . Also, the center frequency fA of the first filter section 101, which is a BFP, is greater than (fs2)/2. Also, the frequency of the sine wave signal is fLo. A component 202 of the sine wave signal is a component generated by the generator 113 . In addition, FIG. 6A shows the difference fA-fLo.

A component 201 (first signal) is a high frequency component that is a high frequency (first specific frequency) greater than (fs2)/2. Thus, the first signal is a signal containing a signal with a first specific frequency higher than 1/2 of the first sampling frequency fs2. On the other hand, in the fifth filter section 105, components above (fs2)/2 are deleted. Therefore, the signal from fifth filter section 105 does not include component 201 .

FIG. 6B is a diagram showing a component resulting from multiplying the component 201 of the first signal by the component 202 of the sine wave signal by the first multiplier 111 . In the example of FIG. 6B, the first signal component 201 is divided into a low frequency component 203 and a high frequency component 204 . Thus, the first multiplied signal is composed of the low frequency component 203 and the high frequency component 204 . The frequency band of the low frequency component 203 is fLo-fA, and the frequency band of the high frequency component 204 is fLo+fA. The frequency band of the low frequency component 203 is smaller than any of the second frequency component f2, the fifth frequency component f5 and (fs2)/2. Also, the frequency band of the high frequency component 204 is larger than any of the second frequency component f2, the fifth frequency component f5, and (fs2)/2, and smaller than (fs1)/2. The intensity of low frequency component 203 and high frequency component 204 is less than the intensity of component 201 .

FIG. 6C is a diagram showing that the high frequency component 204 of the first multiplied signal (the low frequency component 203 and the high frequency component 204) has been removed by the second filter section 102, which is the LPF. Therefore, the low frequency component 203 of the component 201 higher than (fs2)/2 is extracted. This low frequency component 203 corresponds to the second signal.

Thus, the center frequency fA of the first frequency component of the first filter section 101 is greater than (fs2)/2. Also, the center frequency fA is less than (fs1)/2. Furthermore, the frequency fLo of the sine wave signal is set so that the following formula (A) holds.
fLo−fA<(fs2)/2 (A)
Similarly, with respect to the current component, the sixth filter section 106 extracts the component less than (fs2/2) (the component corresponding to the low frequency component 203) as the sixth signal. Also, based on the same principle as in FIG. 6, the component corresponding to the low frequency component 203 is input to the communication section 114 as the fourth signal. Also, in the sixth filter unit 106, components above (fs2)/2 are deleted.

FIG. 7 is a diagram showing a case where the signal extracted by the first filter section 101 contains the noise component fN later. The frequency fN of the noise component 210 in the example of FIG. 7 is included in the band below (fs2)/2.

In this case, the noise component 210 is divided into a low-frequency noise component 211 and a high-frequency noise component 212 by the first multiplier 111 multiplying the noise component 210 by the sine wave signal. As shown in FIG. 7, the frequency of the low-frequency noise component 211 is fLo-fN, and the frequency of the high-frequency noise component 212 is fLo+fN. fLo-fN and fLo+fN are greater than (fs2)/2.

Next, second filter section 102 removes frequency components greater than (fs2)/2, so not only high frequency component 204 but also low frequency noise component 211 and high frequency noise component 212 can be removed. Therefore, even if the noise component 210 is included in the signal output from the first filter unit 101, the processing unit 30 can remove the noise component. For the same reason, even if the noise component 210 is included in the signal output from the third filter unit 103, the processing unit 30 can remove the noise component.

FIG. 8 shows first filter section 101, first multiplier section 111, and second filter section when center frequency fA of first filter section 101 is 50 Hz and the frequency of the sine wave signal is 52 Hz. 102 is a diagram for explaining the processing of 102. FIG.

FIG. 8A shows an example of the first signal from the first filter section 101 whose center frequency is 50 Hz. FIG. 8B is an example of the first multiplication signal. The first multiplied signal is a signal obtained by multiplying the first signal by a sine wave signal having a frequency fLo of 52 Hz by the first multiplier 111 . The first multiplied signal in the example of FIG. 8(B) is a combined signal of a signal of 2 Hz (=fLo-fA) and a signal of 102 Hz (=fLo+fA).

FIG. 8(C) is an example of the second signal generated by the second filter section 102 . In the example of FIG. 8C, the second signal is 2 Hz (=fLo-fA). FIG. 8D shows a signal sampled by the communication unit 114. FIG. That is, FIG. 8(D) is the signal transmitted to the impedance calculator 50 .

[Impedance calculator]
FIG. 9 is a functional block diagram of the impedance calculator 50. As shown in FIG. The impedance calculation unit 50 includes a ninth filter unit 51, a tenth filter unit 52, an eleventh filter unit 58, a twelfth filter unit 59, a phase unit 53, reciprocal units 54 and 55, a multiplication unit 56, 57 , an eleventh filter section 58 and a twelfth filter section 59 .

In the following, the currents (fourth and sixth signals) transmitted from processing unit 30 are also referred to as I(t). The voltages (second signal and fifth signal) transmitted from the processing unit 30 are also referred to as V(t). where "t" is the time variable.

A current I(t) is input to the ninth filter unit 51 . Ninth filter section 51 extracts the frequency band component of current I(t) and outputs it to phase section 53 and reciprocal section 54 . Hereinafter, the current frequency band component extracted by the ninth filter unit 51 is also referred to as an “extracted current component” or a “current component”. The current component is called Iω(t). Also, the frequency band may be a predetermined frequency band, or may be calculated by a predetermined method.

The reciprocal part 54 calculates 1/Iω(t), which is the reciprocal of the current component Iω(t). The reciprocal 1/Iω(t) calculated by the reciprocal unit 54 is output to the multiplication unit 56 .

The phase unit 53 performs a calculation to shift the phase of the current component Iω(t) by π/2. Here, the “operation for shifting the phase by π/2” may be an operation for advancing the phase by π/2 or an operation for delaying the phase by π/2. The π/2 shift operation corresponds to the “first operation” of the present disclosure. In the present embodiment, the first calculation is calculation for delaying the phase of the current component Iω(t) by π/2.

As will be described later, the phase unit 53 may shift at least one of the phase of the current component and the phase of the voltage component relatively by π/2. 52 may be connected.

The current component for which the first calculation is performed (the phase is shifted by π/2) is also referred to as “current component Iωd(t)”. The current component Iωd(t) calculated by the phase section 53 is output to the reciprocal section 55 . The reciprocal part 55 calculates 1/Iωd(t), which is the reciprocal of the current component Iωd(t). The reciprocal 1/Iωd(t) calculated by the reciprocal unit 54 is output to the multiplication unit 56 .

A voltage V(t) is input to the tenth filter unit 52 . Tenth filter section 52 extracts the frequency band component of voltage V and outputs it to multiplier 56 and multiplier 57 . Hereinafter, the voltage frequency band component extracted by the tenth filter unit 52 is also referred to as “voltage component Vω(t)”. Also, the frequency band used by the ninth filter section 51 and the frequency band used by the tenth filter section 52 are the same. The voltage component Vω(t) extracted by the tenth filter section 52 is output to the multiplier section 56 and the multiplier section 57 .

Multiplication section 56 multiplies 1/Iω(t) from reciprocal section 54 by Vω(t) from tenth filter section 52 . That is, the multiplier 56 calculates Vω(t)/Iω(t). Thus, the impedance calculator 50 divides Vω(t) from the tenth filter unit 52 by Iω(t) from the reciprocal unit 54 . Thus, in the current component and the voltage component after execution of the first calculation, the calculation of dividing the voltage component by the current component corresponds to the "second calculation" of the present disclosure. Also, Vω(t)/Iω(t) corresponds to the “first value” of the present disclosure.

Multiplication unit 57 multiplies 1/Iωd(t) from reciprocal unit 55 and Vω(t) from tenth filter unit 52 . That is, the multiplier 56 calculates Vω(t)/Iωd(t). In other words, the impedance calculator 50 calculates Vω(t)/Iωd(t) by performing the second calculation of 1/Iωd(t) and Vω(t). Vω(t)/Iωd(t) corresponds to the “second value” of this disclosure.

As described above, the phase section 53 is also called a first calculation section that executes the first calculation. The reciprocal units 54 and 55 and the multiplication units 56 and 57 are also collectively referred to as a second computation unit that executes the above-described second computation.

Vω(t)/Iω(t) from the multiplication section 56 is output to the eleventh filter section 58 . The eleventh filter unit 58 calculates the real part Zre of the impedance of the battery 5 by removing the time-varying component of Vω(t)/Iω(t) (first value). The time-varying component is a component that varies with time, and will be detailed later.

Vω(t)/Iωd(t) from the multiplication unit 57 is output to the twelfth filter unit 59 . The twelfth filter unit 59 calculates the imaginary part Zim of the impedance of the battery 5 by removing the time-varying component of Vω(t)/Iωd(t) (second value).

The integration unit 60 calculates the impedance Z by integrating the real part Zre from the eleventh filter unit 58 and the imaginary part Zim from the twelfth filter unit 59 .

In this embodiment, the fifth signal (VL) is the voltage V(t) and the sixth signal (IL) is the current I(t). The impedance calculator 50 calculates the impedance ZL (first impedance) of the low frequency component based on the fifth signal and the sixth signal. Also, let the second signal (VH) be the voltage V(t), and let the fourth signal (IL) be the current I(t). The impedance calculator 50 calculates the impedance ZH (second impedance) of the high frequency component based on the second signal and the fourth signal. Impedance calculator 50 transmits impedance ZL and impedance ZH to deterioration degree calculator 80 .

The impedance calculator 50 may calculate the impedance ZL of the low frequency component and the impedance ZH of the high frequency component in parallel. Further, the impedance calculator 50 may calculate one of the impedance ZL of the low frequency component and the impedance ZH of the high frequency component, and then calculate the other.

[Impedance plot]
FIG. 10 is an example of an impedance plot generated by the deterioration degree calculator 80. In FIG. The example of FIG. 10 shows an example of an impedance plot in which the impedance ZL of the low frequency component and the impedance ZH of the high frequency component (hereinafter also referred to as “two impedances”) are plotted. there is In FIG. 10, the horizontal axis indicates the real part Zre, and the vertical axis indicates the imaginary part -Zim. Also, in the example of FIG. 10, an arc is drawn by the impedance plot.

FIG. 10A is an example of an impedance plot generated by the deterioration degree calculator 80. FIG. FIG. 10A is also an example of an impedance plot (hereinafter also referred to as a "reference impedance plot") generated when the battery 5 has not deteriorated. A reference impedance plot is stored in the reference impedance storage unit 70 .

Further, in the example of FIG. 10A, a straight line M is shown. A reference line M is a line that indicates the reference of the impedance on the high frequency side and the impedance on the low frequency side. In the example of FIG. 10A, in the real part Zre of the horizontal axis, the impedance plot of the region A1 larger than the reference line M is calculated from the impedance ZL on the low frequency side. In addition, the impedance plot of the region A2, which is smaller than the reference line M in the real part Zre of the horizontal axis, is calculated from the impedance ZH on the high frequency side.

FIG. 10B is a diagram showing an example of an impedance plot in which two impedances calculated by the impedance calculator 50 are plotted when the battery 5 is deteriorating at a high rate. FIG. 10C is a diagram showing an example of an impedance plot in which two impedances calculated by the impedance calculator 50 are plotted when the battery 5 has deteriorated over time.

As shown in FIG. 10A, when the battery 5 has not deteriorated (for example, the initial state immediately after the battery 5 is manufactured), the starting point X of the arc is the initial value of the DC resistance R (hereinafter referred to as (also referred to as initial DC resistance R0). The difference in the real number component between the connection point Y between the arc and the straight line and the starting point X of the arc represents the initial value of the reaction resistance Rct (hereinafter also referred to as the initial reaction resistance Rct0).

As shown in FIG. 10B, as the high-rate deterioration of the battery 5 progresses, the DC resistance R increases. As a result, the starting point of the arc shifts to the right in FIG. 10(B) as indicated by the arrow in FIG. 10(B). In FIG. 10B, the arc starting point RB (RB>R0) is shown.

On the other hand, when the age deterioration of the battery 5 is relatively slow, the arc size RctB does not change much from the arc size Rct0 in the initial state. That is, RB≈R0.

Thereafter, as the aging deterioration of the battery 5 progresses, as shown in FIG. 10C, the arc size increases by ΔRct compared to before the aging deterioration progresses. In FIG. 10C, RC≈RB>R0. Note that in the example shown in FIG. 10C, the progress of high-rate deterioration is suppressed by limiting the current (suppressing charging and discharging with a large current) from the state shown in FIG. 10B. Therefore, almost no shift of the starting point of the arc occurs. That is, RC≈RB.

The deterioration degree calculator 80 creates an impedance plot based on the first impedance and the second impedance. Then, the deterioration degree calculation unit 80 calculates the deterioration degree of the battery 5 by comparing the created impedance plot with the reference impedance plot stored in the reference impedance storage unit 70 (the deterioration degree of the battery 5 is presume).

[flowchart]
FIG. 11 is a flowchart mainly showing the processing of the processing unit 30 of the BMU 100. As shown in FIG. In step S<b>2 , the measurement unit 15 of the BMU 100 detects current charged/discharged to the battery 5 . In step S2, the measurement unit 15 of the BMU 100 also detects the voltage of the battery 5 during the current measurement.

Next, the processing of steps S4 to S18 will be described. The processing of steps S4 to S18 is performed by the processing unit 30. FIG. First, the voltage component signal will be described. In step S<b>4 , the processing unit 30 uses the fifth filter unit 105 to generate a fifth signal. In parallel with step S4, the processing unit 30 causes the first filter unit 101 to generate the first signal in step S6. Next, in step S8, the processing unit 30 multiplies the first signal by the sine wave signal to generate the first multiplied signal. Next, in step S<b>10 , the processing section 30 causes the second filter section 102 to generate a second signal.

Next, the current component signal will be described. In step S<b>12 , the processing unit 30 generates a sixth signal using the sixth filter unit 106 . In parallel with step S12, the processing unit 30 causes the third filter unit 103 to generate a third signal in step S14. Next, in step S16, the processing section 30 generates a second multiplied signal by multiplying the third signal by the sine wave signal. Next, in step S<b>18 , the processing section 30 uses the second filter section 102 to generate a fourth signal.

[Summary]
In general, if the sampling process is performed while the frequency component of half or more of the sampling frequency remains in the signal to be sampled, the effect of aliasing will occur. Therefore, it is conceivable to increase the sampling frequency so as not to cause the influence of aliasing. However, increasing the sampling frequency causes problems such as an increase in the cost of the device. A voltage is measured for each cell in the battery 5 . As the sampling frequency increases, the amount of data in the signal after sampling increases, and as the number of cells increases, the amount of data in the signal increases even more. Also, for example, increasing the sampling frequency of ADC 109 or ADC 110 is conceivable. However, since the sampling frequency in the communication unit 114 is fixed, the sampling frequency is rate-determined.

Therefore, in the present disclosure, the first filter section 101 generates a first signal including a signal with a first specific frequency equal to or higher than half the sampling frequency fs2. The second filter section 102 generates a second signal (low-frequency component 203 in FIG. 6) including signals included in the first signal and having a frequency lower than the first specific frequency. Therefore, the processing unit 30 can acquire the signal of the first specific frequency equal to or higher than half the sampling frequency (fs2) without increasing the sampling frequency.

In addition, in the present disclosure, the second filter unit 102 can generate the second signal from the low frequency component of the signal of the first specific frequency equal to or higher than 1/2 of the sampling frequency fs2 for the voltage signal. Further, the fourth filter unit 104 can generate the fourth signal from the low frequency component of the signal of the second specific frequency equal to or higher than 1/2 of the sampling frequency fs2 for the current signal. Therefore, the processing unit 30 can acquire the signal of the first specific frequency equal to or higher than 1/2 of the sampling frequency without increasing the sampling frequency in either current or voltage.

Also, the first sine wave signal used in the first multiplier 111 and the second sine wave signal used in the second multiplier are sine wave signals having the same frequency and the same phase. Therefore, the processing load can be reduced compared to the case where the first sine wave signal and the second sine wave signal are separate.

Moreover, the impedance calculator 50 calculates the first impedance ZL of the battery 5 on the low frequency side based on the fifth signal and the sixth signal. Also, the impedance calculator 50 calculates a second impedance ZH on the high frequency side of the battery 5 based on the second signal and the fourth signal. Also, the impedance calculator 50 generates an impedance plot based on the first impedance ZL and the second impedance ZH. Then, the degree of deterioration of the battery is calculated. Then, the deterioration degree calculator 80 calculates the deterioration degree of the battery 5 based on the impedance plot.

With the configuration of the comparative example in FIG. 3, the second impedance ZH on the high frequency side cannot be calculated because the signal of the first specific frequency (signal on the high frequency side) is deleted. In the present embodiment, the signal of the first specific frequency can be acquired, so the second impedance ZH can be calculated. Therefore, the BMU 100 can calculate the degree of deterioration of the battery 5 more accurately.

Also, the ninth filter unit 51 extracts the ninth signal (IL) from the ninth frequency component of the sixth signal (IL). The tenth filter section 52 extracts the tenth frequency component of the fifth signal (VL) as the tenth signal (VL). Then, the impedance calculator 50 performs a first calculation to relatively shift at least one of the phase of the ninth signal and the phase of the tenth signal by π/2. Also, the impedance calculator 50 calculates the first value and the second value (see FIG. 9) by executing the second calculation using the ninth signal and the tenth signal after the execution of the first calculation. Then, the impedance calculator 50 calculates the first impedance ZL of the battery 5 on the low frequency side by removing the time-varying component from the first value and the second value.

Also, the ninth filter section 51 extracts the ninth signal (IH) from the signal of the ninth frequency component of the fourth signal (IH). The tenth filter section 52 extracts the tenth frequency component of the second signal (VH) as the tenth signal (VH). Then, the impedance calculator 50 performs a first calculation to relatively shift at least one of the phase of the ninth signal and the phase of the tenth signal by π/2. In addition, the impedance calculator 50 performs the second calculation using the ninth signal (IH) and the tenth signal (VH) after the execution of the first calculation, thereby obtaining the third value and the fourth value (Fig. 9 ) are calculated. Then, the impedance calculator 50 calculates the second impedance ZH on the high frequency side of the battery 5 by removing the time-varying component from the third value and the fourth value.

For example, in calculating the impedance described in Japanese Patent Application Laid-Open No. 2021-12065, it is necessary to apply a sinusoidal current in order to calculate the impedance. Therefore, a problem of wasteful power consumption may arise. With the impedance calculator 50 of the present disclosure, it is possible to reduce wasteful power consumption and calculate the impedance of the battery.

Further, the second calculation is a calculation of dividing the component of the tenth signal by the component of the ninth signal in the ninth signal (current signal) and the tenth signal (voltage signal) after the execution of the first calculation. . Therefore, the second calculation can be executed with a relatively simple calculation.

Further, the impedance calculator 50 calculates the real part of the first impedance by removing the time-varying component from the first value, and calculates the imaginary part of the first impedance by removing the time-varying component from the second value. is calculated, and the first impedance is calculated by integrating the real part and the imaginary part. Further, the impedance calculator 50 calculates the real part of the second impedance by removing the time-varying component from the third value, and calculates the imaginary part of the second impedance by removing the time-varying component from the fourth value. and integrating the real part and the imaginary part to calculate the second impedance. Therefore, the first impedance and the second impedance can be calculated by relatively simple calculations.

[Principle by formula]
Next, the principle of the processing of the first filter section 101, the first multiplication section 111, the second filter section 102, the third filter section 103, the second multiplication section 112, and the fourth filter section 104 will be described using mathematical expressions.

The complex impedance, which is the impedance of the battery 5, is expressed by dividing it into a real part and an imaginary part. Then, when Z=V/I, the third signal is represented by the following equation (1).

When the complex impedance of the impedance of the battery 5 is indicated by "Z", the complex impedance Z is represented by the following equation (1).

Z=|Z|·ejφ (1)
Here, "e" on the right side of equation (1) indicates the base of natural logarithms, "j" indicates the imaginary number, "φ" indicates the phase, and |Z| indicates the absolute value of the complex impedance. show. Note that |Z| and φ vary with frequency. Also, the third signal (current signal) can be represented by the following equation (2).
Third signal=Isin(ωAt+φI) (2)
Here, “I” in equation (2) is amplitude, “ωA” represents angular velocity, t represents time variable, and φI represents “phase”.

Also, the first signal (voltage signal) can be expressed by the following equations (3) and (4).
First signal=Vsin(ωAt+φI+φz) (3)
=Vsin(ωAt+φV) (4)
"φz" in equation (3) indicates the phase difference between the current and the voltage. Also, φV in Equation (4) is the sum of φI and φz. Also, the first multiplication signal is represented by the following equation (5).

First multiplication signal=Vsin(ωAt+φV)·cos(ωLt+φL)
=(V/2)·{sin((ωL+ωA)t+φV+φL)+sin(−((ωL−ωA)t−φV+φL))} (5)
Here, in Equation (5) and Equation (6) described later, cos(ωLt+φL) indicates the sine wave signal output from generator 113 .

Further, sin((ωL+ωA)t+φV+φL)) indicates the high frequency component 204 (see FIG. 6) of the voltage signal, and sin(−((ωL−ωA)t−φV+φL)) indicates the low frequency component 203 of the voltage signal. show. Also, the second multiplication signal is represented by the following equation (6).

Second multiplication signal=Isin(ωAt+φV)·cos(ωLt+φL)
=(I/2)·{sin((ωL+ωA)t+φI+φL)+sin(−((ωL−ωA)t−φI+φL))} (6)
Further, sin((ωL+ωA)t+φI+φL)) indicates the high frequency component 204 of the current signal, and sin(−((ωL−ωA)t−φI+φL)) indicates the low frequency component 203 of the current signal.

When φI=φL and φV=φL+φz, the low-frequency component of the voltage signal (that is, the second signal) and the low-frequency component of the current signal (that is, the fourth signal) are expressed by the following equations (7) and (8).

Low frequency component of voltage signal (second signal)
=-(V/2){sin((ωL-ωA)t-φz) (7)
Low frequency component of current signal (4th signal)
=−(V/2){sin((ωL−ωA)t) (8)
As shown in equations (7) and (8), a phase difference φz occurs between the voltage signal and the current signal. The voltage signal of equation (7) and the current signal of equation (8) are input to the impedance calculator 50 .

Next, the principle by which the impedance of the battery 5 is calculated by the calculation by the impedance calculator 50 will be described. In the following, the current signal in equation (7) is I(t) and the voltage signal in equation (8) is V(t). The complex impedance Z is also expressed by the following equation (2A) in addition to the above equation (1).

Z=Zre+jZim (2A)
Here, "Zre" on the right side of Equation (2A) indicates the real part of the impedance, and "Zim" indicates the imaginary part of the impedance. Also, the current I(t) is represented by the following equation (3A).

I(t)=I0+I1.ej.omega.1t+I2.ej.omega.2t+...In.ej.omega.nt...
(3A)
Here, "ωn" on the right side of Equation (3A) indicates the angular frequency of the current I(t), and "t" indicates time. Also, n is an integer of 1 or more and represents each frequency component contained in the current I(t). Also, I0 is a DC component.

When the current I(t) measured by the current measuring unit 10 is represented by the formula (3A), the voltage V(t) is represented by the following formula (4A).

V(t)=I0·|Z0|+I1·|Z1|·ej(ω1t+φ1)
+I2·|Z2|·ej(ω2t+φ2)+...In·|Zn|·ej(ωnt+φn)...
(4A)
As shown in Equation (4A), a phase shift of φn occurs between the current and the voltage with respect to the frequency component of ωn. This phase φn corresponds to the phase difference φz shown in Equation (7).

A ninth filter unit 51 extracts a component of an arbitrary angular frequency ω (a part of the above-described current component) from I(t) of Equation (3A). The extracted current component Iω(t) is represented by the following equation (5A). In addition, in the following formulas, the exponential functions are converted to trigonometric functions for the sake of simplification of calculation.

Iω(t)=Isinωt (5A)
When the extracted current component is given by Equation (5A), the extracted voltage component Vω(t) can be expressed by Equation (6A) below. The extracted voltage component Vω(t) is the voltage component extracted by the tenth filter section 52 .

Vω(t)=I·│Z|·sin(ωt+φ)
=I·│Z|·(cosφ·sinωt+sinφ·cosωt)
(6A)
Further, the calculation of the multiplication unit 56 becomes the following formula (7A).

Vω(t)/Iω(t)
=|Z|·(cosφ·sinωt+sinφ·cosωt)/(sinωt)
=(|Z|·cos φ)+(|Z|·(sin φ)·(1/tan ωt)) (7A)
Here, "|Z|·(sin φ)·(1/tanωt)" on the right side of Equation (7A) is represented by time t. That is, "|Z|·(sinφ)·(1/tanωt)" is a component that varies with time, and is the time-varying component described above. The eleventh filter unit 58 removes this time-varying component. Then, Vω(t)/Iω(t) is represented by the following equation (8A).

Vω(t)/Iω(t)
＝│Z│・cosφ
= Zre (8A)
Thus, the real part of the complex impedance of the battery 5 is calculated by removing the time-varying component by the eleventh filter section 58 .

Further, the current component Iωd(t) whose current phase is delayed by π/2 by the phase unit 53 is expressed by the following equation (9A) using equation (5A).

Iωd(t)=Isin(ωt+(π/2))
= I cos ωt (9A)
Further, the calculation of the multiplier 57 is given by the following equation (10A).

Vω(t)/Iωd(t)
=|Z|·(cosφ·sinωt+sinφ·cosωt)/(cosωt)
=(|Z|·cosφ·tanωt)+(|Z|·sisφ) (10A)
Here, "|Z|·cos φ·tanωt" on the right side of Equation (10A) is represented by time t. That is, "|Z|·cos φ·tan ωt" is a component that varies with time, and is the time-varying component. In the above equation (7A), Vω(t) is divided by Iω(t). In order to prevent Vω(t) from being divided by zero, the division is executed. Similarly, the above equation (10A) divides Vω(t) by Iωd(t), but in order to prevent dividing Vω(t) by zero, when Iωd(t) is not 0 The division is performed.

The twelfth filter section 59 removes this time-varying component. Then, Vω(t)/Iω(t) is represented by the following formula (11A).

Vω(t)/Iωd(t)
＝│Z│・sinφ
= Zim (11A)
Thus, the imaginary part of the complex impedance of the battery 5 is calculated by removing the time-varying component by the twelfth filter section 59 . Then, the integrating section 60 calculates the complex impedance by integrating the real part and the imaginary part of the impedance as shown in the above equation (2A). Thus, the real part and the imaginary part of the complex impedance of the battery 5 are calculated by the processing of the impedance calculator 50 in FIG.
[Modification]
(1) In the example of FIG. 5, the first filter unit 101, the second filter unit 102, and the fifth filter unit 105 are configured by the integrated circuit 122, that is, realized by digital processing (software processing). explained the configuration. However, the processing executed by first filter section 101, second filter section 102, and fifth filter section 105 may employ a configuration implemented by analog circuit 120A. FIG. 12 is a configuration example of a processing section 30A adopting this configuration. Also, in this modification, the ADC 109 corresponds to the “first sampling unit” of the present disclosure. The sampling frequency of ADC 109 is fs1.

The analog circuit 120A has a seventh filter section 107 that is an LPF, a thirteenth filter section 153 that is a BPF, a first multiplication section 111, a generation section 113, and a fourteenth filter section 154 that is an LPF. FIG. 13 is a diagram showing components and the like generated by the analog circuit 120A.

As shown in FIG. 13, the 13th filter unit 153 extracts the signal of the 13th frequency component from the voltage signal V, thereby extracting the component 201 of the first signal. Also, the center frequency fA of the thirteenth filter section 153 is a frequency equal to or higher than (fs1)/2. That is, the first signal includes a signal with a first specific frequency equal to or higher than (fs1)/2. FIGS. 13B and 13C are similar to FIGS. 6B and 6C.

Also, the signal sampled by the ADC 109 is input to the fifth filter section 105 . Fifth filter section 105 removes a signal of (fs2)/2 or more from the signal and outputs the result.

In addition, in the example of FIG. 12, the processing for the voltage signal has been described, but the same processing may be performed for the current signal as well. Even with the processing unit 30A as shown in FIG. 12, the same effects as in the present embodiment can be obtained.

(2) In the above embodiment, the output signal output from the processing unit 30 is used for calculating the impedance and the degree of deterioration. However, the output signal may be used for other purposes. For example, a determination device may be provided outside the processing unit 30 . The determination device may detect noise based on the output signal from the processing section 30 . The noise is, for example, high frequency noise generated in inverter 41 . For example, when noise is generated in the inverter 41, the intensity of the second signal (component 203) in FIG. 6 tends to increase. Therefore, if the intensity of the second signal (component 203) is equal to or greater than a predetermined threshold value, the determination device determines that the noise is occurring. On the other hand, if the intensity of the second signal (component 203) is less than the threshold, the determination device determines that the noise has not occurred. Also, the determination device detects the presence or absence of noise based on the intensity of at least one of the second signal of the current signal and the voltage signal.

(3) The calculation method of the impedance calculator 50 is not limited to that shown in FIG. 9, and may be another method. For example, the impedance calculator 50 may calculate the impedance by dividing the voltage signal by the current signal.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning of equivalents of the scope of the claims.

1 vehicle, 2 drive wheel, 3 motor generator, 5 battery, 10 current measurement unit, 15 measurement unit, 20 voltage measurement unit, 30 processing unit, 41 inverter, 50 impedance calculation unit, 51 ninth filter unit, 52 tenth filter section, 53 phase section, 58 eleventh filter section, 59 twelfth filter section, 60 integration section, 70 reference impedance storage section, 80 deterioration degree calculation section, 114 communication section, 101 first filter section, 102 second filter section, 103 Third Filter Section 104 Fourth Filter Section 105 Fifth Filter Section 106 Sixth Filter Section 107 Seventh Filter Section 108 Eighth Filter Section 111 First Multiplication Section 112 Second Multiplication Section 113 Generation 120, 120A analog circuit 122 integrated circuit 153 thirteenth filter section 154 fourteenth filter section 181 processor 182 memory.

Claims (4)

a first filter section for generating a first signal by extracting a signal of a first frequency component from a battery signal which is at least one of a current signal charged and discharged to and discharged from a chargeable/dischargeable battery and a voltage signal of the battery; ,
a generator that generates a first sine wave signal;
a first multiplier that generates a first multiplied signal by multiplying the first signal by the first sinusoidal signal;
a second filter unit that generates a second signal by extracting a signal of a second frequency component from the first multiplied signal;
a first sampling unit that samples the second signal at a first sampling frequency;
the first signal includes a signal of a first specific frequency greater than half the first sampling frequency;
A processing device, wherein the second signal includes a signal having a frequency lower than the first specific frequency. the battery signal includes the current signal and the voltage signal;
The first filter unit generates the first signal by extracting the signal of the first frequency component from the voltage signal,
The generator generates a second sine wave signal,
The processing device further comprises:
a third filter unit that generates a third signal by extracting a signal of a third frequency component from the current signal;
a second multiplier that generates a second multiplied signal by multiplying the third signal by the second sinusoidal signal;
a fourth filter section for generating a fourth signal by extracting a signal of a fourth frequency component from the second multiplied signal;
a second sampling unit that samples the fourth signal at a second sampling frequency;
the third signal includes a signal of a second specific frequency greater than 1/2 of the second sampling frequency;
2. The processing device according to claim 1, wherein said fourth signal includes a signal with a frequency lower than said second specific frequency. 3. The processor of claim 2, wherein said first sinusoidal signal and said second sinusoidal signal are identical. The processing apparatus according to claim 2 or claim 3;
a first calculator that calculates the impedance of the battery;
A second calculation unit that calculates the degree of deterioration of the battery,
The processing device further comprises:
a fifth filter unit that generates a fifth signal by extracting a signal of a fifth frequency component from the voltage signal;
a sixth filter unit that generates a sixth signal by extracting a signal of a sixth frequency component from the current signal;
a communication unit that transmits the second signal, the fourth signal, the fifth signal, and the sixth signal to the first calculation unit;
The first calculator,
calculating a first impedance on the low frequency side of the battery based on the fifth signal and the sixth signal;
calculating a second impedance on the high frequency side of the battery based on the second signal and the fourth signal;
The calculation system, wherein the second calculation unit estimates the degree of deterioration of the battery based on the first impedance and the second impedance.

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