JP2021139656A - Control device - Google Patents

Abstract

To provide a control device capable of suppressing a decrease in calculation accuracy in an internal resistance of a rechargeable battery even when a current change or a voltage change is not constant.SOLUTION: A control device is applied to a power supply system including a rechargeable battery, a current sensor, a filter circuit arranged in an electric path between the rechargeable battery and the current sensor, and a voltage sensor. When a predetermined change occurs, the control device acquires a detected current detected by the current sensor and a detected voltage detected by the voltage sensor as paired data at a predetermined cycle, linearly approximates a relation between the detected current and the detected voltage included in the paired data, and also calculates an internal resistance of the rechargeable battery based on a slope of the approximated straight line. The control device includes: a change determination unit which determines whether or not a current change of the detected current or a voltage change of the detected voltage included in the paired data is constant in a change period in which a predetermined change occurs; and a calculation unit which calculates the slope of the approximated straight line as the internal resistance of the rechargeable battery on the condition that the current change or the voltage change is determined to be constant.SELECTED DRAWING: Figure 2

Description

The present invention relates to a control device for a power supply system.

Conventionally, there is known a device that calculates the internal resistance of a storage battery based on the current flowing through the storage battery and the voltage of the storage battery (for example, Patent Document 1). In this device, a plurality of pairs of data are acquired by using the detected current detected by the current sensor and the detected voltage detected by the voltage sensor as paired data, and the detected current and the detected voltage included in the paired data are obtained. The slope of the approximate straight line when linearly approximated is calculated as the internal resistance of the storage battery.

Japanese Patent No. 3752888

In order to remove noise contained in the current flowing through the storage battery, a filter circuit may be provided in the electric path between the storage battery and the current sensor. If the filter circuit is provided, for example, even if the current and the voltage change at the same time at the start of charging the storage battery, the timing at which the change appears in the detection current is delayed from the timing at which the detection voltage appears.

By the way, the internal resistance includes an inductance component as well as a resistance component. When this inductance component acts on the current or voltage in the storage battery, the amount of current change, which is the amount of change in the detected current contained in the pair of data per unit time, and the amount of voltage change, which is the amount of change in the detected voltage per unit time, It is not constant, and the amount of current change and the amount of voltage change increase or decrease according to the elapsed time. When the amount of current change or the amount of voltage change increases or decreases according to the elapsed time, if the increase or decrease of the amount of current change lags behind the increase or decrease of the amount of voltage change due to synchronization deviation, the linear approximation of the paired data Decreases. For example, when the amount of current change and the amount of voltage change decrease with the elapsed time, a relatively large amount of current change and a relatively small amount of voltage change are associated with each other in the paired data. Therefore, the slope of the calculated approximate straight line becomes smaller than the internal resistance of the storage battery, and if the slope of the approximate straight line is calculated as the internal resistance of the storage battery, there is a concern that the calculation accuracy of the internal resistance may decrease.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control device capable of suppressing a decrease in calculation accuracy in the internal resistance of a storage battery even when the amount of current change or the amount of voltage change is not constant. It is in.

The first means for solving the above-mentioned problems are a storage battery, a current sensor for detecting the current flowing through the storage battery, a filter circuit provided in an electric path between the storage battery and the current sensor, and the storage battery. When applied to a power supply system including a voltage sensor for detecting voltage and a predetermined change in current or voltage in the storage battery occurs, the detection current detected by the current sensor and the detection detected by the voltage sensor. The voltage is acquired as a pair of data at a predetermined cycle, the relationship between the detected current and the detected voltage included in the paired data is linearly approximated, and the internal resistance of the storage battery is calculated based on the inclination of the approximated straight line. In the change period in which the predetermined change occurs, the current change amount, which is the change amount of the detection current included in the pair of data per unit time, or the change amount of the detection voltage per unit time. On the condition that the change amount determination unit for determining whether or not a certain voltage change amount is constant and the current change amount or the voltage change amount are determined to be constant during the change period, the approximate straight line A calculation unit for calculating the inclination as the internal resistance of the storage battery is provided.

In the control device of the power supply system equipped with the storage battery, the internal resistance of the storage battery is calculated using the current flowing through the storage battery and the voltage of the storage battery. Specifically, when a predetermined change in current or voltage in the storage battery occurs, the detected current detected by the current sensor and the detected voltage detected by the voltage sensor are acquired as paired data at a predetermined cycle. Then, the relationship between the detected current and the detected voltage included in the pair of data is linearly approximated, and the internal resistance of the storage battery is calculated based on the slope of the approximated straight line.

In the control device, a filter circuit for removing noise is provided in the electric path between the storage battery and the current sensor, and this filter circuit causes a synchronization shift between the current sensor and the voltage sensor. Further, the internal resistance of the storage battery contains an inductance component. When this inductance component acts on the current or voltage in the storage battery, the current change amount, which is the amount of change in the detected current per unit time, and the voltage change amount, which is the amount of change in the detected voltage per unit time, are not constant, and the current change. The amount and the amount of voltage change increase or decrease according to the elapsed time. When the amount of current change or the amount of voltage change increases or decreases according to the elapsed time, if the decrease in the amount of current change lags behind the decrease in the amount of voltage change due to synchronization deviation, the linear approximation of the paired data decreases. For example, when the amount of current change and the amount of voltage change decrease with the elapsed time, a relatively large amount of current change and a relatively small amount of voltage change are associated with each other in the paired data. Therefore, the slope of the calculated approximate straight line is smaller than the internal resistance of the storage battery, and if the slope of the approximate straight line is calculated as the internal resistance of the storage battery, the calculation accuracy of the internal resistance is lowered.

In the above configuration, it is determined whether or not the amount of current change or the amount of voltage change is constant during the change period in which a predetermined change occurs, and on the condition that it is determined to be constant, the slope of the approximate straight line is determined inside the storage battery. It is calculated as resistance. Therefore, when the amount of change in current or the amount of change in voltage is not constant, the slope of the approximate straight line is not calculated as the internal resistance of the storage battery, so that a decrease in the calculation accuracy of the internal resistance can be suppressed.

In the second means, when the calculation unit determines that the current change amount or the voltage change amount is not constant during the change period, the calculation unit determines that the current change amount or the voltage change amount is based on the current change amount or the voltage change amount. The inclination is corrected to calculate the internal resistance of the storage battery.

The internal resistance of the storage battery is calculated when the condition that a predetermined change in current or voltage in the storage battery occurs is satisfied. Therefore, when the above conditions are satisfied, if the internal resistance of the storage battery is not calculated because it is determined that the current change amount or the voltage change amount is not constant, the period during which the internal resistance of the storage battery is not calculated becomes long. In that respect, in the above configuration, when it is determined that the current change amount or the voltage change amount is not constant during the change period, the inclination of the approximate straight line is corrected based on the current change amount or the voltage change amount to reduce the internal resistance of the storage battery. I tried to calculate. The amount of change in current and the amount of change in voltage are affected by the inductance component that acts on the current and voltage in the storage battery. Therefore, by correcting the slope of the approximate straight line based on the amount of current change or the amount of voltage change, the influence of the inductance component on the slope of the approximate straight line can be suppressed. As a result, even if it is determined that the amount of change in current or the amount of change in voltage is not constant, the internal resistance of the storage battery can be calculated while suppressing the decrease in calculation accuracy, and the period during which the internal resistance of the storage battery is not calculated can be shortened. be able to.

The third means includes a slope determination unit for determining whether or not the slope of the current change amount is positive or whether or not the slope of the voltage change amount is positive, and the calculation unit includes the change period. When it is determined that the current change amount or the voltage change amount is not constant, and the slope determination unit determines that the slope of the current change amount or the slope of the voltage change amount is positive, the approximate straight line is used. The slope of the storage battery is calculated by reducing the slope of the storage battery, and it is determined that the current change amount or the voltage change amount is not constant during the change period, and the slope determination unit determines the slope of the current change amount or the slope of the current change amount. When it is determined that the slope of the voltage change amount is negative, the slope of the approximate straight line is increased and corrected to calculate the internal resistance of the storage battery.

When the amount of change in current or the amount of change in voltage is not constant, the amount of change increases or decreases according to the elapsed time, and the slope becomes positive or negative. For example, when the slope of the current change amount and the voltage change amount is positive and these changes increase with the elapsed time, the increase in the current change amount is delayed from the increase in the voltage change amount due to the synchronization shift. The slope of the approximate straight line is calculated based on the small amount of current change and the relatively large amount of voltage change. Therefore, the slope of the approximate straight line becomes larger than the internal resistance of the storage battery. Therefore, by reducing and correcting the slope of the approximate straight line, it is possible to calculate the internal resistance of the storage battery while suppressing a decrease in calculation accuracy. Further, for example, when the slope of the current change amount or the voltage change amount is negative and the change amount decreases according to the elapsed time, if the decrease of the current change amount is delayed from the decrease of the voltage change amount due to the synchronization shift, The slope of the approximate straight line is calculated based on a relatively large amount of current change and a relatively small amount of voltage change. Therefore, the slope of the approximate straight line becomes larger than the internal resistance of the storage battery. Therefore, by increasing and correcting the slope of the approximate straight line, it is possible to calculate the internal resistance of the storage battery while suppressing a decrease in calculation accuracy.

In the fourth means, the power supply system is applied to a vehicle equipped with an engine and a starter motor, and power is supplied to the starter motor when the engine is started, and the inclination determination unit is the starter motor. When the predetermined change occurs with the engine start by the engine, it is determined that the slope of the current change amount or the slope of the voltage change amount is negative.

When the engine is started by the starter motor, the discharge current flowing through the storage battery temporarily rises, and the amount of change in the discharge current sharply increases and then decreases. Therefore, when a predetermined change occurs with the engine start, the slope of the current change amount and the voltage change amount becomes negative. Therefore, by reducing and correcting the inclination of the approximate straight line, it is possible to calculate the internal resistance of the storage battery while suppressing a decrease in calculation accuracy when the engine is started by the starter motor.

In a fifth means, the power supply system includes a rotary electric machine that performs at least one of power generation by supplying electric power from the storage battery and power generation for charging the storage battery, and if required, the rotary electric machine. Is driven in a power running state or a power generation state, and the inclination determination unit determines the amount of change in the current when the predetermined change occurs as the inclination of the load amount gradually increases when the rotary electric machine is driven. When it is determined that the inclination or the inclination of the voltage change amount is positive and the predetermined change occurs as the inclination of the load amount gradually decreases when the rotary electric machine is driven, the inclination of the current change amount or the above-mentioned It is determined that the slope of the voltage change amount is negative.

When the slope gradually increases with the change in the load amount when the rotary electric machine is driven, the current change amount of the charge / discharge current flowing through the storage battery gradually increases, so that the slope of the current change amount or the slope of the voltage change amount Is positive. Therefore, when a predetermined change occurs as the load amount gradually increases, the internal resistance of the storage battery can be calculated while suppressing a decrease in calculation accuracy by increasing and correcting the slope of the approximate straight line. .. Further, when the slope of the load amount gradually decreases when the rotary electric machine is driven, the slope of the current change amount or the slope of the voltage change amount becomes negative because the current change amount of the charge / discharge current flowing through the storage battery gradually decreases. .. Therefore, by reducing and correcting the slope of the approximate straight line, it is possible to calculate the internal resistance of the storage battery with high accuracy while suppressing a decrease in calculation accuracy.

Overall configuration diagram of the power supply system. A flowchart showing a procedure of control processing. A time chart showing the transition of the detected current when the vehicle is running. A time chart showing changes in the detected voltage and the detected current when the voltage change is constant. The figure which shows the relationship between the detected current and the detected voltage when the voltage change is constant. A time chart showing changes in the detected voltage and the detected current when the slope of the voltage change is negative. The figure which shows the relationship between the detection current and the detection voltage when the slope of the voltage change is negative. A time chart showing changes in the detected voltage and the detected current when the slope of the voltage change is positive. The figure which shows the relationship between the detection current and the detection voltage when the slope of the voltage change is positive. The figure which shows the slope map of a voltage change.

(Embodiment)
Hereinafter, an embodiment in which the control device according to the present invention is applied to a power supply system 100 mounted on a vehicle traveling with an engine as a drive source will be described with reference to the drawings.

As shown in FIG. 1, the power supply system 100 is a system that supplies electric power to a rotary electric machine 10, an electric load 12, and a starter motor (hereinafter, starter) 26. The power supply system 100 includes a first battery 13, a second battery 14 as a storage battery, a voltage sensor 16, a current sensor 18, a filter circuit 20, and a control device 30.

The rotary electric machine 10 has functions of power running drive and regenerative power generation, and specifically, is an MG (Motor Generator) or an ISG (Integrated Starter Generator). The rotary electric machine 10 inputs and outputs electric power to and from the first battery 13 and the second battery 14. The rotary shaft of the rotary electric machine 10 is driven and connected to an engine output shaft (not shown) by a belt or the like. Rotates the engine output shaft. The rotary electric machine 10 is driven by power supply from at least one of the first battery 13 and the second battery 14 at the time of power running drive, and applies a rotational force to the engine output shaft. Further, at the time of regenerative power generation, the rotary electric machine 10 generates power by rotating the engine output shaft and charges at least one of the first battery 13 and the second battery 14.

The electric load 12 includes a constant voltage required load and a general load. Here, the constant voltage required load is a load that is required to be stable so that the voltage of the supplied power is substantially constant, or at least changes within a predetermined range, and the general load is a load other than the constant voltage load. ..

The first battery 13 and the second battery 14 are rechargeable and dischargeable storage batteries, and are assembled batteries in which a plurality of battery cells are connected in series. The first battery 13 is, for example, a lead storage battery, which is a well-known general-purpose storage battery. On the other hand, the second battery 14 is, for example, a lithium ion storage battery. Therefore, the second battery 14 is a high-density storage battery having a smaller power loss during charging / discharging, a higher output density, and a higher energy density than the first battery 13.

FIG. 1 shows an equivalent circuit of the internal resistance 24 of the second battery 14 together with the battery cell assembly 22 of the second battery 14. The internal resistance 24 is configured as a series connection of two sets of resistance components, a first resistance component RA representing the DC resistance of the second battery 14 and a reaction resistance component in the positive electrode and the negative electrode. The reaction resistance component is configured as a parallel circuit having a second resistance component RB, a coil component LB, and a capacitance component CB. That is, the second battery 14 has the resistance components RA and RB as well as the inductance components LB and CB such as the coil component LB and the capacitance component CB as circuit components of the equivalent circuit of the internal resistance 24.

The voltage sensor 16 is connected to a connection point PA between the second battery 14, the rotary electric machine 10 and the electric load 12, and the second battery between the connection point PA and the negative electrode voltage of the second battery 14. 14 voltages are detected. The current sensor 18 detects the current flowing in the electric path NA connecting the connection point PA, the rotary electric machine 10 and the electric load 12. Specifically, a shunt resistor RC is provided in the electric path NA between the connection point PA and the rotary electric machine 10 and the electric load 12, and both ends of the shunt resistor RC pass through the electric paths NB and NC. Is connected to the current sensor 18. The current sensor 18 detects the current flowing through the shunt resistor RC as the current flowing through the second battery 14. The detected current IE detected by the current sensor 18 and the detected voltage VE detected by the voltage sensor 16 are input to the control device 30.

The filter circuit 20 is provided in the electric paths NB and NC connecting the second battery 14 and the current sensor 18. The filter circuit 20 is a low-pass filter composed of filter resistors RD and RE and a filter capacitor CD, and removes noise included in the current flowing through the second battery 14. The filter resistors RD and RE are provided in the respective electric paths NB and NC. Both ends of the filter capacitor CD are connected between the filter resistors RD and RE and the current sensor 18 in each of the electric paths NB and NC, respectively.

The starter 26 is connected to the connection point PB between the shunt resistor RC in the electric path NA and the rotary electric machine 10 and the electric load 12. The rotation shaft of the starter 26 is driven and connected to the engine output shaft, and a rotational force is applied to the engine by supplying electric power from at least one of the first battery 13 and the second battery 14. The starter 26 applies a rotational force to the engine when the engine is started for the first time. In the following, the first start of the engine by the starter 26 will be referred to as the engine start by the starter 26.

The starter 26 and the connection point PB are connected by an electric path ND, and the first battery 13 is connected to the connection point PC between the starter 26 and the connection point PB in the electric path ND. A first switch 28 is provided between the connection point PA and the connection point PB in the electric path NA, and a second switch 29 is provided between the connection point PC and the connection point PB in the electric path ND. Has been done.

Each of the first and second switches 28 and 29 has a first switching element and a second switching element connected in series. In this embodiment, an N-channel MOSFET is used as the first and second switching elements. The first and second switching elements have a parasitic diode, and in the first and second switches 28 and 29, the first and second switching elements are connected in series so that the anodes of the parasitic diodes are connected to each other. There is. Further, in the first switch 28, a shunt resistor RC is arranged between the first switching element and the second switching element.

The control device 30 includes a well-known microcomputer including a CPU, ROM, RAM, flash memory, and the like. Further, the control device 30 is connected to the power switch 32, the vehicle speed sensor 34 for detecting the vehicle speed MV, and the accelerator sensor 36. The power switch 32 is a vehicle start switch. The control device 30 monitors the open / closed state of the power switch 32. The vehicle speed sensor 34 is a sensor that detects the vehicle speed MV, which is the speed of the vehicle. The accelerator sensor 36 is a sensor that detects the accelerator operation amount AC, which is the operation amount of the accelerator pedal 40. The control device 30 realizes various functions for controlling the vehicle by referring to the arithmetic program and various data in the ROM.

Specifically, the control device 30 drives the rotary electric machine 10 in a power running state or a power generation state in response to a request such as an accelerator operation by a driver. Further, the control device 30 generates a control signal SD in order to control the first and second switches 28 and 29, and outputs the control signal SD to the first and second switches 28 and 29. The open / closed state of the first and second switches 28 and 29 is switched by the control signal SD.

Further, the control device 30 calculates the resistance value RF of the first resistance component RA as the internal resistance based on the detection current IE input from the current sensor 18 and the detection voltage VE input from the voltage sensor 16. .. The control device 30 calculates the resistance value RF when a predetermined change in the current or voltage in the second battery 14 occurs. Here, the predetermined change is a change in which the current change amount ΔI, which is a change amount (absolute value) of the detected current IE per unit time, becomes larger than the predetermined current threshold Isth, or a change amount of the detected voltage VE per unit time (absolute value). This is a change in which the voltage change amount ΔV, which is an absolute value), becomes larger than the predetermined voltage threshold Vth, and the change period TB (see FIG. 4) at which the change occurs is equal to or longer than the reference period.

When this predetermined change occurs, the control device 30 acquires the detected current IE and the detected voltage VE as paired data in the change period TB in a predetermined period TA (see FIG. 4). Then, the relationship between the detected current IE and the detected voltage VE included in the acquired pair of data is linearly approximated, and the resistance value RF is calculated based on the slope XA of the approximated straight line. For example, the control device 30 calculates the slope XA of the approximate straight line as the resistance value RF.

By the way, in the power supply system 100 of the present embodiment, the filter circuit 20 is provided in the electric paths NB and NC between the second battery 14 and the current sensor 18. Therefore, for example, when the charging of the second battery 14 is started, even if the current and the voltage of the second battery 14 change at the same time, the timing at which the change appears in the detection current IE is delayed from the timing at which the detection voltage VE appears. Occurs.

Further, in the power supply system 100 of the present embodiment, the internal resistance 24 includes the inductance components LB and CB. When the inductance components LB and CB act on the current and voltage in the second battery 14, the current change amount ΔI of the detection current IE and the voltage change amount ΔV of the detection voltage VE included in the pair of data are not constant, and these The amount of change increases or decreases depending on the elapsed time. When the current change amount ΔI and the voltage change amount ΔV increase or decrease according to the elapsed time, if the increase or decrease of the current change amount ΔI lags behind the increase or decrease of the voltage change amount ΔV due to the synchronization shift, the paired data The linear approximation of is reduced.

For example, when the voltage change amount ΔV decreases with the elapsed time, a relatively large current change amount ΔI and a relatively small voltage change amount ΔV are associated with each other in the pair of data. Therefore, the slope XA of the calculated approximate straight line becomes smaller than the resistance value RF, and when the slope XA of the approximate straight line is calculated as the resistance value RF, the calculation accuracy of the resistance value RF decreases.

In the present embodiment, in the change period TB, it is determined whether or not the voltage change amount ΔV is constant, and on the condition that it is determined to be constant, the slope XA of the approximate straight line is calculated as the resistance value RF. The process is now carried out. Therefore, when the voltage change amount ΔV is not constant, the slope XA of the approximate straight line is not calculated as the resistance value RF, so that it is possible to suppress a decrease in the calculation accuracy of the resistance value RF.

FIG. 2 is a flowchart showing a processing procedure of a control process for calculating the resistance value RF of the second battery 14. The control device 30 is implemented when the above-mentioned predetermined change occurs when the power switch 32 is in the closed state.

When the control process is started, first, in step S10, it is determined whether or not the predetermined change is completed. When the predetermined change is not completed and multiple pairs of data for calculating the resistance value RF are not acquired, or when the change of current or voltage is completed, the change period TB is less than the reference period. In that case, a negative determination is made in step S10. In this case, the control process ends.

On the other hand, when the predetermined change is completed and the change period TB has elapsed, an affirmative determination is made in step S10. In this case, in step S12, the slope DV of the voltage change amount ΔV of the detection voltage VE included in the pair of data acquired in the change period TB, that is, the change speed of the voltage change amount ΔV is calculated. In the following step S14, it is determined whether or not the voltage change amount ΔV is constant during the change period TB. In this embodiment, the process of step S14 corresponds to the "change amount determination unit".

In step S14, it is determined whether or not the absolute value of the slope DV calculated in step S12 is smaller than the predetermined first threshold value ΔVth1. When the absolute value of the slope DV is smaller than the first threshold value ΔVth1 and the voltage change amount ΔV is constant, a positive determination is made in step S14. In this case, since the slope XA of the approximate straight line is equal to the resistance value RF, in step S16, the slope XA of the approximate straight line is calculated as the resistance value RF, and the control process is terminated.

On the other hand, when the absolute value of the slope DV is larger than the first threshold value ΔVth1 and the voltage change amount ΔV is not constant, a negative determination is made in step S14. In this case, in step S18, it is determined whether or not the absolute value of the slope DV is smaller than the second threshold value ΔVth2 set to a value larger than the first threshold value ΔVth1.

If the absolute value of the slope DV is larger than the second threshold value ΔVth2 and the acquired pair of data is linearly approximated and the error becomes significantly large, a negative determination is made in step S18. In this case, since the slope XA of the approximate straight line itself cannot be calculated with a predetermined accuracy, the control process is terminated without calculating the resistance value RF.

On the other hand, when the absolute value of the slope DV is smaller than the second threshold value ΔVth2 and the slope XA of the approximate straight line can be calculated with a predetermined accuracy from the acquired pair of data, an affirmative determination is made in step S18. In this case, in steps S20 to S24, the slope XA of the approximate straight line is corrected based on the voltage change amount ΔV, and the resistance value RF is calculated. Specifically, first, in step S20, it is determined whether or not the inclination DV is positive. In this embodiment, the process of step S20 corresponds to the “tilt determination unit”.

When the slope DV is positive, the slope XA of the approximate straight line becomes larger than the resistance value RF. Therefore, if an affirmative determination is made in step S20, in step S22, the slope XA of the approximate straight line is reduced and corrected to calculate the resistance value RF, and the control process is terminated.

On the other hand, when the slope DV is negative, the slope XA of the approximate straight line becomes smaller than the resistance value RF. Therefore, if a negative determination is made in step S20, in step S24, the slope XA of the approximate straight line is increased and corrected to calculate the resistance value RF, and the control process is terminated. In this embodiment, the processes of steps S16, S22, and S24 correspond to the “calculation unit”.

Subsequently, FIG. 3 shows the transition of the detected current IE when the vehicle is running. In FIG. 3, (A) shows the transition of the vehicle speed MV, (B) shows the transition of the detected current IE, and (C) shows the transition of the accelerator operation amount AC. In (B), the charging current is described as positive and the discharging current is described as negative.

In the example shown in FIG. 3, the accelerator operation amount AC is constant during the period from time t0 to time t1, and the vehicle speed MV and the detected current IE are also constant accordingly.

When the accelerator operation amount AC increases in response to the accelerator operation by the driver at time t1, the vehicle speed MV continues to increase from the time t1 to the time t3 when the accelerator operation is performed. Further, the detection current IE decreases due to the increase in the discharge current in the second battery 14. Since the second battery 14 includes the internal resistance 24, the detected current IE slowly decreases as compared with the accelerator operation amount AC, as shown in FIG. 3 (B). Specifically, the detected current IE decreases with a predetermined slope from the time t1 to the time t2 before the time t3.

At the subsequent time t3, when the accelerator operation amount AC becomes zero in response to the end of the accelerator operation by the driver, the vehicle speed MV continues to decrease due to the regenerative power generation of the rotary electric machine 10. Further, the current flowing through the second battery 14 is switched from the discharge current to the charge current, and the detection current IE increases due to the increase in the charge current. Since the second battery 14 includes the internal resistance 24, the detected current IE slowly increases as compared with the accelerator operation amount AC, as shown in FIG. Specifically, the detected current IE increases with a predetermined slope over the period from time t3 to time t4.

That is, the detected current IE has a change period TB that increases or decreases with a predetermined inclination due to the internal resistance 24 of the second battery 14. The control device 30 calculates the resistance value RF when the change in the change period TB is a predetermined change in which the current change amount ΔI becomes larger than the current threshold value Is.

4, FIG. 6 and FIG. 8 show an example of the control process in the change period TB from the time t3 to the time t4. FIG. 4 shows the transition of the detected voltage VE and the detected current IE when the voltage change amount ΔV in the change period TB is constant. In FIGS. 4, 6 and 8, (A) shows the transition of the detected voltage VE, (B) shows the transition of the detected current IE, and (C) shows the transition of the voltage change amount ΔV.

In the example shown in FIG. 4, as shown in FIG. 4C, the voltage change amount ΔV is constant, and the slope DV is zero. Therefore, as shown in FIG. 4A, the detection voltage VE increases with a constant slope in the period from the time t3 when the accelerator operation amount AC decreases to the time t16 before the time t4, and then becomes constant. Become.

On the other hand, since the filter circuits 20 are provided in the electric paths NB and NC between the second battery 14 and the current sensor 18, a synchronization shift occurs between the detection voltage VE and the detection current IE. Therefore, as shown in FIG. 4B, the detected current IE increases with a constant slope in the period from the time t12 to the time t4 after the time t3, and then becomes constant thereafter.

In the control process, the detection current IE and the detection voltage VE are acquired at the same timing for each predetermined cycle TA in the change period TB from the time t3 to the time t4. Specifically, the detection current IE and the detection voltage VE are acquired as paired data at time t3, time t4, and between times t11 and t17. Then, the resistance value RF is calculated based on the data of these pairs.

FIG. 5 shows the relationship between the detected current IE and the detected voltage VE in the paired data acquired at each time t3, t11 to t17, t4 in FIG. As shown in FIG. 5, since there is a synchronization shift between the detection voltage VE and the detection current IE, the detection current IE changes in the pair of data acquired during the period from time t3 to time t12. In the paired data acquired during the period from time t16 to time t4, the detection voltage VE has not changed. Therefore, it is not possible to calculate the slope XA of the approximate straight line from the paired data acquired during these periods. On the other hand, in the pair of data acquired from the time t12 to the time t16, the detection current IE and the detection voltage VE change. Therefore, the slope XA of the approximate straight line is calculated using the paired data acquired during these periods.

Here, if a synchronization shift occurs between the detected voltage VE and the detected current IE, a synchronization shift also occurs between the current change amount ΔI and the voltage change amount ΔV. Specifically, as shown in FIGS. 4A and 4B, the voltage change amount ΔVA in the period from time t3 to time t11 corresponds to the current change amount ΔIA in the period from time t12 to time t13. It is a thing. Therefore, the slope XA of the approximate straight line calculated based on the current change amount ΔIA and the voltage change amount ΔVA becomes equal to the resistance value RF. However, in the paired data, the voltage change amount ΔVA is associated with the voltage change amount ΔVB in the period from time t12 to time t13, and the slope of the approximate straight line is based on the current change amount ΔIA and the voltage change amount ΔVB. XA is calculated.

As shown in FIG. 4C, when the voltage change amount ΔV is constant, the voltage change amount ΔVA and the voltage change amount ΔVB become equal. Therefore, the slope XA of the approximate straight line calculated based on the current change amount ΔIA and the voltage change amount ΔVB is equal to the slope XA of the approximate straight line calculated based on the current change amount ΔIA and the voltage change amount ΔVA. Therefore, as shown in FIG. 5, the slope of the approximate straight line XA calculated based on the current change amount ΔIA and the voltage change amount ΔVB is calculated as the resistance value RF without deteriorating the linear approximation of the pair of data. be able to.

FIG. 6 shows the transition of the detected voltage VE and the detected current IE when the slope DV of the voltage change amount ΔV in the change period TB is negative, and FIG. 7 shows the transition at each time t3, t11 to t17, t4 in FIG. The relationship between the detected current IE and the detected voltage VE in the acquired pair of data is shown. Since the various timings in FIG. 6 are the same as those in FIG. 4, duplicated description will be omitted.

As shown in FIG. 6C, when the slope DV of the voltage change amount ΔV is negative, the voltage change amount ΔVB becomes smaller than the voltage change amount ΔVA. Therefore, the slope of the approximate straight line XA calculated based on the current change amount ΔIA and the voltage change amount ΔVB is smaller than the slope XA of the approximate straight line calculated based on the current change amount ΔIA and the voltage change amount ΔVA. .. Therefore, as shown in FIG. 7, the linear approximation of the paired data is reduced, and when the slope XA of the approximate straight line calculated based on the current change amount ΔIA and the voltage change amount ΔVB is calculated as the resistance value RF, the resistance The calculation accuracy of the value RF decreases.

In the present embodiment, when the slope DV of the voltage change amount ΔV is negative, the slope XA of the approximate straight line calculated based on the current change amount ΔIA and the voltage change amount ΔVB is not calculated as the resistance value RF. The slope XA of the approximate straight line is increased and corrected to calculate the resistance value RF. As a result, the slope of the approximate straight line XA calculated based on the current change amount ΔIA and the voltage change amount ΔVB is brought closer to the slope XA of the approximate straight line calculated based on the current change amount ΔIA and the voltage change amount ΔVA. This makes it possible to suppress a decrease in the calculation accuracy of the resistance value RF.

FIG. 8 shows the transition of the detected voltage VE and the detected current IE when the slope DV of the voltage change amount ΔV in the change period TB is positive, and FIG. 9 shows the transition of the detected voltage VE and the detected current IE at each time t3, t11 to t17, t4 in FIG. The relationship between the detected current IE and the detected voltage VE in the acquired pair of data is shown. Since the various timings in FIG. 8 are the same as those in FIG. 4, duplicated description will be omitted.

As shown in FIG. 8C, when the slope DV of the voltage change amount ΔV is positive, the voltage change amount ΔVB becomes larger than the voltage change amount ΔVA. Therefore, the slope of the approximate straight line XA calculated based on the current change amount ΔIA and the voltage change amount ΔVB is larger than the slope XA of the approximate straight line calculated based on the current change amount ΔIA and the voltage change amount ΔVA. .. Therefore, as shown in FIG. 9, the linear approximation of the paired data is reduced, and when the slope XA of the approximate straight line calculated based on the current change amount ΔIA and the voltage change amount ΔVB is calculated as the resistance value RF, the resistance The calculation accuracy of the value RF decreases.

In the present embodiment, when the slope DV of the voltage change amount ΔV is positive, the slope XA of the approximate straight line calculated based on the current change amount ΔIA and the voltage change amount ΔVB is not calculated as the resistance value RF. The slope XA of the approximate straight line is reduced and corrected to calculate the resistance value RF. As a result, the slope of the approximate straight line XA calculated based on the current change amount ΔIA and the voltage change amount ΔVB is brought closer to the slope XA of the approximate straight line calculated based on the current change amount ΔIA and the voltage change amount ΔVA. This makes it possible to suppress a decrease in the calculation accuracy of the resistance value RF.

When the slope XA of the approximate straight line is increased or decreased, the correction amount for correcting the slope XA of the approximate straight line is determined based on the slope DV. Correspondence information in which the inclination DV and the correction amount are associated is stored in the storage unit 38 of the control device 30, and the control device 30 determines the correction amount using this correspondence information. In the correspondence information, the inclination DV and the correction amount are associated with each other so that the correction amount becomes larger as the inclination DV becomes larger.

FIG. 10 shows the slope map MP of the voltage change amount ΔV. The tilt map MP is stored in the storage unit 38 of the control device 30. In the tilt map MP, each drive in the engine or the rotary electric machine 10 is associated with whether the tilt DV is positive or negative.

In the tilt map MP, the engine start by the starter 26 is associated with a negative tilt DV. When the engine is started by the starter 26, the discharge current flowing through the second battery 14 temporarily rises, and the current change amount ΔI of the discharge current sharply increases and then decreases. Therefore, when a predetermined change occurs due to the engine start by the starter 26, it can be determined that the inclination DV is negative without comparing the inclination DV with zero.

Further, in the inclination map MP, the inclination DV can be switched between being positive and negative based on the change mode of the inclination of the load amount in the rotary electric machine 10. Here, the load amount is generated by driving the rotary electric machine 10 in the power running state or the power generation state. For example, the rotary electric machine 10 applies a rotational force to the engine output shaft in response to an accelerator operation by the driver (hereinafter referred to as power assist). A load amount is generated when driving in a power running state in which (simply assist) is performed. Further, in response to the charging request of the second battery 14, the load amount in the power generation state is generated when the rotary electric machine 10 drives the power generation state in which the regenerative power generation is performed. In this embodiment, the accelerator operation by the driver and the request for charging the second battery 14 correspond to the "request".

Specifically, in the inclination map MP, when the rotary electric machine 10 is driven, the inclination of the load amount, which is the increase amount of the load amount per unit time, gradually decreases, which is associated with the negative inclination DV. Has been done. Here, when the slope of the load amount gradually decreases, it includes a case where the rotational force applied to the engine output shaft by the assist gradually decreases and a case where the amount of power generated by the regenerative power generation gradually decreases. In these cases, the amount of change ΔI of the charge / discharge current flowing through the second battery 14 gradually decreases. Therefore, when a predetermined change occurs as the load amount gradually decreases when the rotary electric machine 10 is driven, it can be determined that the inclination DV is negative without comparing the inclination DV with zero.

Further, in the inclination map MP, the gradual increase in the inclination of the load amount when the rotary electric machine 10 is driven is associated with the fact that the inclination DV is positive. Here, when the slope of the load amount gradually increases, it includes a case where the rotational force applied to the engine output shaft by the assist gradually increases and a case where the amount of power generated by the regenerative power generation gradually increases. In these cases, the amount of change ΔI of the charge / discharge current flowing through the second battery 14 gradually increases. Therefore, when a predetermined change occurs as the load amount gradually increases when the rotary electric machine 10 is driven, it can be determined that the inclination DV is positive without comparing the inclination DV with zero.

According to the present embodiment described above, the following effects are obtained.

In the present embodiment, it is determined whether or not the voltage change amount ΔV is constant in the change period TB in which a predetermined change occurs, and only when it is determined that the voltage change amount ΔV is constant, the slope XA of the approximate straight line is set to the resistance value RF. It was calculated as. Therefore, when the voltage change amount ΔV is not constant, the slope XA of the approximate straight line is not calculated as the resistance value RF, so that it is possible to suppress a decrease in the calculation accuracy of the resistance value RF.

-In the present embodiment, the linear approximation of the paired data is determined by determining whether or not the voltage change amount ΔV is constant. Therefore, the processing load of the control device 30 in the above determination can be reduced as compared with the case where the linear approximation of the paired data is determined using the correlation function.

-On the other hand, the resistance value RF is calculated only when the condition that a predetermined change in the current or voltage in the second battery 14 occurs is satisfied, so that the voltage change amount ΔV is not constant when the above condition is satisfied. If the resistance value RF is not calculated due to the determination, the period during which the resistance value RF is not calculated becomes long. In this case, the charging / discharging of the second battery 14 cannot be controlled based on the resistance value RF.

In that respect, in the present embodiment, when it is determined that the voltage change amount ΔV is not constant during the change period TB, the slope XA of the approximate straight line is corrected based on the voltage change amount ΔV to calculate the resistance value RF. bottom. The voltage change amount ΔV is affected by the inductance components LB and CB acting on the current and voltage in the second battery 14. Therefore, by correcting the slope XA of the approximate straight line based on the voltage change amount ΔV, the influence of the inductance components LB and CB on the slope XA of the approximate straight line can be suppressed. As a result, even when it is determined that the voltage change amount ΔV is not constant, the resistance value RF can be calculated while suppressing a decrease in calculation accuracy, and the period during which the resistance value RF is not calculated can be shortened.

Specifically, when it is determined that the slope DV of the voltage change amount ΔV is positive, the slope XA of the approximate straight line is reduced and corrected to calculate the resistance value RF. Further, when it is determined that the slope DV of the voltage change amount ΔV is negative, the slope XA of the approximate straight line is increased and corrected to calculate the resistance value RF. As a result, the slope XA of the approximate straight line can be appropriately corrected based on the voltage change amount ΔV, and the decrease in the calculation accuracy of the resistance value RF can be suppressed.

-In the present embodiment, in the tilt map MP, the engine start by the starter 26 is associated with the fact that the tilt DV is negative. When the engine is started by the starter 26, the amount of change ΔI of the discharge current flowing through the second battery 14 increases sharply and then decreases. Therefore, when a predetermined change occurs with the engine start, the slope DV of the voltage change amount ΔV becomes negative. Therefore, by reducing and correcting the slope XA of the approximate straight line, it is possible to calculate the resistance value RF while suppressing a decrease in calculation accuracy when the engine is started by the starter 26.

-In the present embodiment, in the tilt map MP, the gradual increase in the load amount when the rotary electric machine 10 is driven is associated with the positive tilt DV. When the load amount gradually increases when the rotary electric machine 10 is driven, the current change amount ΔI of the charge / discharge current flowing through the second battery 14 gradually increases, so that the slope DV of the voltage change amount ΔV becomes positive. Therefore, when a predetermined change occurs as the load amount gradually increases, the resistance value RF can be calculated while suppressing a decrease in calculation accuracy by increasing and correcting the slope XA of the approximate straight line. ..

On the other hand, in the tilt map MP, the gradual decrease in the load amount when the rotary electric machine 10 is driven is associated with the fact that the tilt DV is negative. When the load amount gradually decreases when the rotary electric machine 10 is driven, the current change amount ΔI of the charge / discharge current flowing through the second battery 14 gradually decreases, so that the slope DV of the voltage change amount ΔV becomes negative. Therefore, when a predetermined change occurs as the load amount gradually decreases, the resistance value RF can be calculated while suppressing a decrease in calculation accuracy by reducing and correcting the slope XA of the approximate straight line. ..

(Other embodiments)
Each of the above embodiments may be modified as follows.

-The "storage battery" is not limited to the lithium ion storage battery, and may be another secondary battery that can be charged and discharged.

-The "filter circuit" is not limited to the low-pass filter, and may be another filter that causes a synchronization shift.

-The "predetermined change" is not limited to the above, and may be, for example, a change in which the detected current IE becomes larger than a predetermined threshold value, or a change in which the detected voltage VE becomes larger than a predetermined threshold value.

-As the "current change amount and voltage change amount", the correlation value may be used instead of the current change amount ΔI and the voltage change amount ΔV, or together with the current change amount ΔI and the voltage change amount ΔV.

-In the above embodiment, the linear approximation of the pair of data is determined based on the voltage change amount ΔV, but the determination may be made based on the current change amount ΔI. However, since the detection current IE used for calculating the current change amount ΔI is detected via the filter circuit 20, the change amount of the current change amount ΔI is suppressed as compared with the voltage change amount ΔV. Therefore, the linear approximation of the paired data can be suitably determined by making a determination based on the voltage change amount ΔV.

-Similarly, in the above embodiment, the slope XA of the approximate straight line is corrected based on the voltage change amount ΔV, but it may be corrected based on the current change amount ΔI.

-In the above embodiment, an example in which the rotary electric machine 10 is MG or ISG is shown, but it does not have to have the function of a generator. It is assumed that the control device 30 automatically stops and restarts the engine according to a predetermined condition when the rotary electric machine 10 does not have the function of a generator. In this case, the starter 26 applies a rotational force to the engine not only when the engine is first started but also when the engine is restarted, and the engine start by the starter 26 includes the restart of the engine as well as the first start of the engine. Therefore, in the tilt map MP, these starts may be associated with the negative tilt DV.

-In the above embodiment, the example in which the internal resistance 24 of the second battery 14 has the coil component LB is shown, but it does not necessarily have to have the coil component LB. The rotary electric machine 10 to which the second battery 14 is connected has a coil. Therefore, the second battery 14 does not have to have the coil component LB when an event occurs in which the current change amount ΔI and the voltage change amount ΔV are not constant due to the coil of the rotary electric machine 10.

The "control device" may be applied to a power supply system 100 mounted on an electric vehicle that does not have an engine. In an electric vehicle, the starter 26 does not start the engine or assist. On the other hand, even in an electric vehicle, regenerative power generation of the rotary electric machine 10 is performed. Therefore, in the electric vehicle, in the inclination map MP, it is sufficient that the inclination DV is positive and negative based on the change in the load amount at the time of driving the power generation state.

The controls and methods described herein are provided by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. It may be realized. Alternatively, the control device and method thereof described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control device and method thereof described in the present disclosure may be a combination of a processor and memory programmed to perform one or more functions and a processor composed of one or more hardware logic circuits. It may be realized by one or more dedicated computers configured. Further, the computer program may be stored in a computer-readable non-transitional tangible recording medium as an instruction executed by the computer.

ΔI ... current change amount, ΔV ... voltage change amount, 14 ... second battery, 16 ... voltage sensor, 18 ... current sensor, 20 ... filter circuit, 100 ... power supply system, RF ... resistance value, XA ... slope of a line.

Claims (5)

The storage battery (14), the current sensor (18) that detects the current flowing through the storage battery, the filter circuit (20) provided in the electric path between the storage battery and the current sensor, and the voltage of the storage battery are detected. Applied to a power supply system (100) with a voltage sensor (16) and
When a predetermined change in current or voltage in the storage battery occurs, the detection current detected by the current sensor and the detection voltage detected by the voltage sensor are acquired as paired data at a predetermined cycle, and the paired data is used. A control device that linearly approximates the relationship between the detected current included and the detected voltage and calculates the internal resistance (RF) of the storage battery based on the slope of the approximate straight line (XA).
During the change period in which the predetermined change occurs, the current change amount (ΔI), which is the change amount of the detected current included in the pair of data per unit time, or the voltage change amount, which is the change amount of the detected voltage per unit time. A change amount determination unit that determines whether (ΔV) is constant, and
A control device including a calculation unit that calculates the slope of the approximate straight line as the internal resistance of the storage battery on condition that the current change amount or the voltage change amount is determined to be constant during the change period. When it is determined that the current change amount or the voltage change amount is not constant during the change period, the calculation unit corrects the slope of the approximate straight line based on the current change amount or the voltage change amount. The control device according to claim 1, wherein the internal resistance of the storage battery is calculated. A tilt determination unit for determining whether or not the slope of the current change amount is positive or whether or not the slope of the voltage change amount is positive is provided.
The calculation unit
When it is determined that the current change amount or the voltage change amount is not constant during the change period, and the inclination determination unit determines that the current change amount inclination or the voltage change amount inclination is positive. The slope of the approximate straight line is reduced and corrected to calculate the internal resistance of the storage battery.
When it is determined that the current change amount or the voltage change amount is not constant during the change period, and the inclination determination unit determines that the current change amount inclination or the voltage change amount inclination is negative. The control device according to claim 1 or 2, wherein the slope of the approximate straight line is increased and corrected to calculate the internal resistance of the storage battery. The power supply system is applied to a vehicle equipped with an engine and a starter motor (26), and supplies electric power to the starter motor when the engine is started.
The control device according to claim 3, wherein the inclination determining unit determines that the inclination of the current change amount or the inclination of the voltage change amount is negative when the predetermined change occurs with the engine start by the starter motor. .. The power supply system includes a rotary electric machine (10) that performs at least one of power running by supplying electric power from the storage battery and power generation for charging the storage battery, and powers the rotary electric machine according to a request. Or it is driven in a power generation state,
The tilt determination unit
When the predetermined change occurs as the slope of the load amount gradually increases when the rotary electric machine is driven, it is determined that the slope of the current change amount or the slope of the voltage change amount is positive.
3. 4. The control device according to 4.

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