Control device, control method and storage medium of power supply circuit

Abstract

The present disclosure relates to a control device, a control method and a storage medium for a power supply circuit. The control device for the power supply circuit includes a processing circuit, the processing circuit having a charging rate calculation unit for calculating the charging rate of a first battery and a target calculation unit for calculating a target voltage range, the charging rate calculation unit, when an acquisition abnormality occurs that makes it impossible to acquire the output voltage of the first battery detected by a voltage sensor, calculates the charging rate of the first battery calculated at a timing before the acquisition abnormality occurs as a maintained charging rate after the acquisition abnormality occurs, and the target calculation unit, when a pre-charging process is performed in a state where the acquisition abnormality occurs, calculates an estimated output voltage of the first battery based on the maintained charging rate, and calculates the target voltage range based on the estimated output voltage.

Description

Technical Field

[0001] The present disclosure relates to a control device of a power supply circuit, a non-transitory computer-readable storage medium storing a power supply circuit control program, and a control method of a power supply circuit. Background Art

[0002] The power system disclosed in Japanese Patent Publication No. 2008-289326 has a first battery composed of a secondary battery. A voltage sensor for detecting the output voltage of the first battery is connected to the first battery. In addition, an electric load is connected to the first battery via a relay for cutting off / connecting the electrical connection. In addition, the power system has a second battery with a lower rated voltage than the first battery. A converter for boosting the output voltage of the second battery is connected to the second battery. The converter is connected to the part between the relay and the electric load, and supplies the boosted output voltage to the electric load.

[0003] The control device of the power system performs a pre-charging process before starting to supply power from the first battery to the electric load. The pre-charging process is a process of boosting the converter until the output voltage supplied from the converter to the electric load substantially matches the target voltage in a state where the electrical connection between the first battery and the electric load is cut off by a relay. When performing the pre-charging process, the control device determines the output voltage of the first battery detected by the voltage sensor as the target voltage.

[0004] The control device may not be able to grasp the output voltage of the first battery due to, for example, a communication failure between the control device and the voltage sensor, a failure of the voltage sensor, etc. In this case, the target voltage cannot be set, and thus the precharge process cannot be performed. Summary of the invention

[0005] According to one embodiment of the present disclosure, a control device for a power supply circuit is provided. The power supply circuit comprises: a first battery; a voltage sensor configured to detect an output voltage of the first battery; a relay configured to cut off / make electrical connection from the first battery to a load; a second battery having a lower rated voltage than the first battery; and a converter configured to boost the output voltage of the second battery and output the boosted output voltage to a portion between the relay and the load. The control device includes a processing circuit configured to perform a pre-charging process, the pre-charging process being a process of performing a voltage-boosting drive of the converter until the output voltage of the converter becomes a value within a target voltage range determined based on the output voltage of the first battery in a state where the electrical connection between the first battery and the load is cut off by the relay, the processing circuit having: a charging rate calculation unit configured to calculate a charging rate of the first battery; and a target calculation unit configured to calculate the target voltage range, the charging rate calculation unit being configured to: in the case of an acquisition abnormality in which the output voltage of the first battery detected by the voltage sensor cannot be acquired, after the timing of the acquisition abnormality, calculate the charging rate of the first battery calculated at a timing before the acquisition abnormality occurs as a holding charging rate, the target calculation unit being configured to: in the case of the pre-charging process being performed in the state where the acquisition abnormality is occurring, calculate an estimated output voltage of the first battery based on the holding charging rate, and calculate the target voltage range based on the estimated output voltage.

[0006] According to one embodiment of the present disclosure, there is provided a non-transitory computer-readable storage medium storing a power supply circuit control program. The power supply circuit control program is executed in a processing circuit of a control device of a power supply circuit having a first battery, a voltage sensor configured to detect an output voltage of the first battery, a relay configured to cut off / make electrical connection from the first battery to a load, a second battery having a lower rated voltage than the first battery, and a converter configured to boost the output voltage of the second battery and output the boosted output voltage to a portion between the relay and the load. When the processing circuit is executed, the processing circuit is caused to execute: a pre-charging process of performing a voltage step-up drive of the converter until the output voltage of the converter reaches a value within a target voltage range determined based on the output voltage of the first battery in a state where the electrical connection between the first battery and the load is cut off by the relay; a charging rate calculation process of calculating the charging rate of the first battery; and a target calculation process of calculating the target voltage range, the charging rate calculation process including the following processes: in a case where an acquisition abnormality occurs that makes it impossible to acquire the output voltage of the first battery detected by the voltage sensor, after the timing when the acquisition abnormality occurs, calculating the charging rate of the first battery calculated at a timing before the acquisition abnormality occurs as a holding charging rate, and the target calculation process including the following processes: in a case where the pre-charging process is executed in a state where the acquisition abnormality is occurring, calculating an estimated output voltage of the first battery based on the holding charging rate, and calculating the target voltage range based on the estimated output voltage.

[0007] According to one embodiment of the present disclosure, a control method for a power supply circuit is provided. The power supply circuit comprises: a first battery; a voltage sensor configured to detect an output voltage of the first battery; a relay configured to cut off / make an electrical connection from the first battery to a load; a second battery having a lower rated voltage than the first battery; and a converter configured to boost the output voltage of the second battery and output the boosted output voltage to a portion between the relay and the load. The control method includes: performing a pre-charging process, which is a process of performing a boost drive of the converter until the output voltage of the converter becomes a value within a target voltage range determined based on the output voltage of the first battery in a state where the electrical connection between the first battery and the load is cut off by the relay; performing a charging rate calculation process, which is a process of calculating the charging rate of the first battery; and performing a target calculation process, which is a process of calculating the target voltage range, the charging rate calculation process including the following processes: in the case of an acquisition abnormality in which the output voltage of the first battery detected by the voltage sensor cannot be acquired, after the timing of the acquisition abnormality, calculating the charging rate of the first battery calculated at the timing before the acquisition abnormality occurs as a maintenance charging rate, the target calculation process including the following processes: in the case of performing the pre-charging process in the state where the acquisition abnormality is occurring, calculating the estimated output voltage of the first battery based on the maintenance charging rate, and calculating the target voltage range based on the estimated output voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a schematic diagram of the vehicle's power system.

[0009] Figure 2 : is a flowchart showing the processing procedure of the charging rate calculation processing.

[0010] Figure 3 It is a diagram showing an example of a characteristic map.

[0011] Figure 4 : is a flowchart showing the processing procedure of the precharge processing.

[0012] Figure 5 1 is a timing chart showing an example of time changes of various parameters in the charging rate calculation process and the pre-charging process. DETAILED DESCRIPTION

[0013] Hereinafter, one embodiment of a control device for a power supply circuit will be described with reference to the drawings.

[0014] First, a schematic configuration of an electric power system mounted on a vehicle will be described.

[0015] like Figure 1 As shown, a hybrid vehicle (hereinafter referred to as a vehicle) 10 is equipped with an internal combustion engine 12 as a driving source of the vehicle 10. In addition, the vehicle 10 is equipped with a motor generator 14 as a driving source different from the internal combustion engine 12. The motor generator 14 has both functions of a motor and a generator.

[0016] The vehicle 10 is equipped with a first battery 22 as a secondary battery that exchanges power with the motor generator 14. That is, the first battery 22 supplies power to the motor generator 14 or stores power generated by the motor generator 14. The first battery 22 is a battery for driving the vehicle 10, and the rated voltage is, for example, about 200 [V] to 250 [V]. A first battery voltage sensor 24 is connected between the terminals of the first battery 22 to detect the output voltage of the first battery 22 as a battery output voltage VB.

[0017] The first battery 22 is connected to a buck-boost converter 80 that bucks and outputs a voltage via a pair of power lines. Specifically, the positive terminal of the first battery 22 is connected to the buck-boost converter 80 via a first positive line 31. In addition, the negative terminal of the first battery 22 is connected to the buck-boost converter 80 via a first negative line 32.

[0018] A current sensor 26 for detecting the charge / discharge current AB flowing through the first battery 22 is provided midway in the first positive line 31. In this embodiment, the charge / discharge current AB is detected as a positive value when the first battery 22 is discharged and as a negative value when the first battery 22 is charged.

[0019] A positive relay 35 is provided on the first positive line 31. The positive relay 35 is located in the portion between the current sensor 26 and the buck-boost converter 80. The positive relay 35 can disconnect / connect the electrical connection between the first battery 22 and the buck-boost converter 80. In addition, a negative relay 36 for disconnecting / connecting the electrical connection between the first battery 22 and the buck-boost converter 80 is installed in the middle of the first negative line 32. When the positive relay 35 and the negative relay 36 are switched to the disconnected state, the electrical connection between the first battery 22 and the buck-boost converter 80 is disconnected. When the positive relay 35 and the negative relay 36 are switched to the connected state, the electrical connection between the first battery 22 and the buck-boost converter 80 is connected.

[0020] The bidirectional converter 50 is connected to the first positive line 31 and the first negative line 32. Specifically, the bidirectional converter 50 is connected to a portion of the first positive line 31 between the positive relay 35 and the buck-boost converter 80 and a portion of the first negative line 32 between the negative relay 36 and the buck-boost converter 80. The second battery 29 as a secondary battery is connected to the bidirectional converter 50. The second battery 29 is a battery for auxiliary machine driving, and the rated voltage is, for example, about 12 [V] to 48 [V].

[0021] Although not shown in the figure, the bidirectional converter 50 is configured to include transistors and diodes, and to step up and down the voltage and output it. Specifically, the bidirectional converter 50 steps up the output voltage of the second battery 29 and outputs it to the first positive line 31 and the first negative line 32. In addition, the bidirectional converter 50 steps down the voltage of the first positive line 31 and the first negative line 32 and outputs it to the second battery 29. The bidirectional converter 50 is connected to a converter voltage sensor 52 that detects the output voltage from the bidirectional converter 50 to the first positive line 31 and the first negative line 32 as the converter output voltage VD.

[0022] In this embodiment, the power supply circuit 16 is configured to include a first battery 22, a first battery voltage sensor 24, a current sensor 26, a first positive line 31, a first negative line 32, a positive relay 35, a negative relay 36, a second battery 29, a bidirectional converter 50 and a converter voltage sensor 52.

[0023] The first capacitor 41 for smoothing the voltage between the first battery 22 and the buck-boost converter 80 is connected to the first positive line 31 and the first negative line 32. Specifically, the first capacitor 41 is connected to a portion of the first positive line 31 between a connection point of the bidirectional converter 50 and the buck-boost converter 80 and a portion of the first negative line 32 between another connection point of the bidirectional converter 50 and the buck-boost converter 80. A first capacitor voltage sensor 43 for detecting a charging voltage of the first capacitor 41 as a first charging voltage VC1 is connected between the terminals of the first capacitor 41.

[0024] In the above-mentioned step-up / step-down converter 80, a first transistor 81 and a second transistor 82 as switching elements are connected in series. The first transistor 81 and the second transistor 82 are both npn-type transistors. A first diode 85 for reflux is connected in parallel to the first transistor 81. A second diode 86 for reflux is connected in parallel to the second transistor 82.

[0025] The first positive line 31 is connected to the connection point of the emitter terminal of the first transistor 81 and the collector terminal of the second transistor 82 via the inductor 88. The collector terminal of the first transistor 81 is connected to the converter 90 via the second positive line 71. The emitter terminal of the second transistor 82 is connected to the first negative line 32, and the converter 90 is connected via the second negative line 72. The converter 90 is connected to the motor generator 14. It should be noted that, although omitted from the figure, a control voltage is input to the base terminal of the first transistor 81 and the base terminal of the second transistor 82, and the control voltage is used to switch the on / off of these transistors. The converter 90 converts DC power and AC power between the step-up / step-down converter 80 and the motor generator 14.

[0026] The second capacitor 61 for smoothing the voltage between the step-up / step-down converter 80 and the inverter 90 is connected to the second positive line 71 and the second negative line 72. A second capacitor voltage sensor 63 is connected between the terminals of the second capacitor 61 to detect the charging voltage of the second capacitor 61 as a second charging voltage VC2.

[0027] In this embodiment, the electric load (hereinafter referred to as load) 18 is configured to include the motor generator 14, the inverter 90, and the step-up / step-down converter 80. And a series of power systems including the load 18, the power supply circuit 16, and the first capacitor 41 and the second capacitor 61 constitute a power system.

[0028] Next, the control configuration of the vehicle 10 will be described.

[0029] The vehicle 10 is equipped with a vehicle control device 100 for controlling various parts of the vehicle 10 including the power system. The vehicle control device 100 can be configured as one or more processors that perform various processes according to a computer program (software). It should be noted that the vehicle control device 100 can also be configured as one or more dedicated hardware circuits such as an integrated circuit (ASIC: Application Specific Integrated Circuit) for a specific purpose that performs at least a part of the various processes, or a processing circuit (processing circuitry) including a combination thereof. The processor includes a CPU and memories such as RAM and ROM. The memory stores program codes or instructions configured to enable the CPU to perform processing. The memory, i.e., a computer-readable storage medium, includes all available media that can be accessed by a general or dedicated computer. For example, a power circuit control program can be stored in a non-temporary computer-readable storage medium.

[0030] Detection signals from various sensors mounted on the vehicle 10 are input to the vehicle control device 100. Specifically, the following detection signals are input to the vehicle control device 100.

[0031] The battery output voltage VB detected by the first battery voltage sensor 24

[0032] The charge and discharge current AB detected by the current sensor 26

[0033] Converter output voltage VD detected by converter voltage sensor 52

[0034] The first charging voltage VC1 detected by the first capacitor voltage sensor 43

[0035] The second charging voltage VC2 detected by the second capacitor voltage sensor 63

[0036] Here, the battery output voltage VB detected by the first battery voltage sensor 24 may not be acquired by the vehicle control device 100 due to an abnormality in the communication line between the first battery voltage sensor 24 and the vehicle control device 100. The vehicle control device 100 includes an abnormality determination unit 102 that determines whether an acquisition abnormality that makes it impossible to acquire the battery output voltage VB has occurred.

[0037] The vehicle control device 100 includes a charging rate calculation unit 104 that calculates the charging rate SOC of the first battery 22. As shown in the following equation (1), the charging rate SOC is a value obtained by dividing the remaining capacity YL of the first battery 22 by the full charge capacity YA.

[0038] SOC[%]=YL[Ah] / YA[Ah]×100···(1)

[0039] The charging rate calculation unit 104 calculates the maintained charging rate KSOC as the charging rate SOC maintained in response to the occurrence of an acquisition abnormality. In this embodiment, the charging rate calculation unit 104 calculates the maintained charging rate KSOC regardless of whether the acquisition abnormality occurs. When no acquisition abnormality occurs, the charging rate calculation unit 104 calculates the charging rate SOC of the first battery 22 directly as the maintained charging rate KSOC. When an acquisition abnormality occurs, the charging rate calculation unit 104 calculates the charging rate SOC of the first battery 22 calculated at the timing before the acquisition abnormality occurs as the maintained charging rate KSOC after the timing when the acquisition abnormality occurs. In this embodiment, when an acquisition abnormality occurs, the charging rate calculation unit 104 calculates the charging rate SOC of the first battery 22 calculated last before the acquisition abnormality occurs as the maintained charging rate KSOC.

[0040] Here, when the ignition switch G of the vehicle 10 is turned on, the positive relay 35 and the negative relay 36 are switched to the connection state, and power starts to be supplied from the first battery 22 to the buck-boost converter 80. At this time, if a large current flows instantaneously from the high-voltage first battery 22 to the buck-boost converter 80, the positive relay 35 and the negative relay 36 may be welded. Therefore, before starting to supply power from the first battery 22 to the buck-boost converter 80, the following process needs to be performed: the first capacitor 41 is charged in a state where the electrical connection between the first battery 22 and the buck-boost converter 80 is cut off. By charging the first capacitor 41 in advance, the voltage difference between the first battery 22 and the first capacitor 41 becomes small, and the current flowing through the positive relay 35 and the negative relay 36 can be suppressed to be small.

[0041] The vehicle control device 100 has a precharge execution unit 106 that executes a precharge process as a process for charging the first capacitor 41. The precharge execution unit 106 is responsible for controlling various parts of the power supply circuit 16 such as the bidirectional converter 50 and the relay in the precharge process. In addition, the precharge execution unit 106 maintains the positive relay 35 and the negative relay 36 in the cut-off state during the precharge process, and performs a boost drive of the bidirectional converter 50 until the output voltage of the bidirectional converter 50 becomes a value within the target voltage range VZ determined based on the output voltage of the first battery 22. It should be noted that during the execution of the precharge process, the charging voltage of the first capacitor 41 is substantially the same as the output voltage of the bidirectional converter 50. In addition, when the precharge process is performed, the buck-boost converter 80 and the converter 90 are both in a non-driving state. At this time, the first positive line 31 and the second positive line 71 are connected via the first diode 85, so that the charging voltage of the second capacitor 61 is also substantially the same as the output voltage of the bidirectional converter 50. Therefore, the precharge execution unit 106 increases the charging voltage of the first capacitor 41 and the second capacitor 61 to the target voltage range VZ in the precharge process.

[0042] The precharge execution unit 106 calculates the above-mentioned target voltage range VZ when executing the precharge process. When no acquisition abnormality occurs, the precharge execution unit 106 calculates the target voltage range VZ based on the battery output voltage VB detected by the first battery voltage sensor 24. When an acquisition abnormality occurs, the precharge execution unit 106 calculates the estimated output voltage EVB of the first battery 22 based on the maintained charge rate KSOC of the first battery 22, and calculates the target voltage range VZ based on the estimated output voltage EVB. In this way, in this embodiment, the precharge execution unit 106 functions as a target calculation unit that calculates the target voltage range VZ.

[0043] The vehicle control device 100 has a charge and discharge determination unit 108 that determines whether the first battery 22 can be charged and discharged. The charge and discharge determination unit 108 allows the charge and discharge of the first battery 22 when no acquisition abnormality occurs. On the other hand, the charge and discharge determination unit 108 prohibits the charge and discharge of the first battery 22 when an acquisition abnormality occurs. In order to reflect whether the charge and discharge of the first battery 22 can be charged and discharged in the control of the electric generator 14, the charge and discharge determination unit 108 sets a charge and discharge prohibition flag FN indicating that the charge and discharge of the first battery 22 is prohibited. When no acquisition abnormality occurs, the charge and discharge determination unit 108 sets the charge and discharge prohibition flag FN to OFF. When an acquisition abnormality occurs, the charge and discharge determination unit 108 sets the charge and discharge prohibition flag FN to ON.

[0044] The vehicle control device 100 has a drive source control unit 110 that controls the internal combustion engine 12 and the electric generator 14. It should be noted that the drive source control unit 110 substantially controls the electric generator 14 by controlling the step-up / step-down converter 80 and the converter 90. When the charge / discharge prohibition flag FN is turned off (OFF), the drive source control unit 110 sets the step-up / step-down converter 80 and the converter 90 to a driving state to control the electric generator 14 to a driving state. On the other hand, when the charge / discharge prohibition flag FN is enabled (ON), the drive source control unit 110 sets the step-up / step-down converter 80 and the converter 90 to a non-driving state to control the electric generator 14 to a non-driving state. That is, the drive source control unit 110 makes the electric generator 14 function neither as a motor nor as a generator. In this case, the drive source control unit 110 only drives the internal combustion engine 12.

[0045] Next, the determination process of whether or not there is an acquisition abnormality performed by the abnormality determination unit 102 is described. The abnormality determination unit 102 repeatedly performs the determination process of whether or not there is an acquisition abnormality from the time the ignition switch G is turned on to the time it is turned off. It should be noted that, as a prerequisite for this process, the abnormality determination unit 102 repeatedly receives the battery output voltage VB detected by the first battery voltage sensor 24.

[0046] The abnormality determination unit 102 determines that an acquisition abnormality has occurred when the situation in which the battery output voltage VB cannot be acquired from the first battery voltage sensor 24 continues for more than a predetermined specified time. The above-mentioned specified time is determined to be a time that is sufficiently longer than the acceptance cycle of the battery output voltage VB. It should be noted that the situation in which the abnormality determination unit 102 cannot acquire the battery output voltage VB occurs, for example, when the communication line between the first battery voltage sensor 24 and the vehicle control device 100 is disconnected or the connector of the communication line is detached from the input port of the vehicle control device 100, resulting in a communication failure.

[0047] Furthermore, even when the battery output voltage VB from the first battery voltage sensor 24 can be obtained, the abnormality determination unit 102 determines that an acquisition abnormality has occurred when the battery output voltage VB is a value that deviates from a predetermined normal range. The normal range is determined as a range of values ​​that the battery output voltage VB can normally take. It should be noted that the situation in which the battery output voltage VB becomes a value that deviates from the normal range occurs, for example, when an abnormality occurs in the first battery voltage sensor 24 and the first battery voltage sensor 24 cannot properly detect the battery output voltage VB.

[0048] The abnormality determination unit 102 determines that no acquisition abnormality has occurred when any of the above conditions are not met. The abnormality determination unit 102 sets the acquisition abnormality flag FC to ON when it determines that an acquisition abnormality has occurred. The abnormality determination unit 102 sets the acquisition abnormality flag FC to OFF when it determines that no acquisition abnormality has occurred.

[0049] Next, the charging rate calculation process performed by the charging rate calculation unit 104 is described. The charging rate calculation process is a process for calculating the charging rate SOC and the maintained charging rate KSOC of the first battery 22. The charging rate calculation unit 104 repeatedly performs the charging rate calculation process from the time when the ignition switch G is turned on to the time when it is turned off. It should be noted that when the ignition switch G is turned off, the charging rate calculation unit 104 does not clear the maintained charging rate KSOC maintained at that time point, but stores the maintained charging rate KSOC until the next time the ignition switch G is turned on.

[0050] like Figure 2 As shown, after starting the charging rate calculation process, the charging rate calculation unit 104 executes the process of step S10. In step S10, the charging rate calculation unit 104 determines whether the acquisition abnormality flag FC is enabled (ON). When the acquisition abnormality flag FC is turned off (step S10: No), the charging rate calculation unit 104 proceeds to step S110.

[0051] In step S110, the charging rate calculation unit 104 calculates the charging rate SOC of the first battery 22. In this embodiment, the charging rate calculation unit 104 calculates the charging rate SOC using the so-called current integration method. Here, the charging rate calculation unit 104 calculates the integral value SAB of the charge and discharge current AB from the time when the ignition switch G is turned on in the background. The charging rate calculation unit 104 obtains the latest integral value SAB of the charge and discharge current AB when calculating the charging rate SOC. Then, as shown in the following formula (2), the charging rate calculation unit 104 adds the value obtained by dividing the integral value SAB of the charge and discharge current AB by the full charge capacity YA of the first battery 22 to the initial charging rate YS to calculate the charging rate SOC. The charging rate calculation unit 104 stores the full charge capacity YA of the first battery 22 in advance. The initial charging rate YS is the charging rate SOC of the first battery 22 at the time when the ignition switch G is turned on, that is, the maintained charging rate KSOC stored by the charging rate calculation unit 104 at the time when the ignition switch G is turned on. The charging rate calculation unit 104 stores the initial charging rate YS while the ignition switch G is turned on.

[0052] SOC[%]=YS[%]+(SAB[Ah]÷YA[Ah])×100···(2)

[0053] After executing the process of step S110 , the charging rate calculation unit 104 proceeds to step S120 .

[0054] In step S120, the charging rate calculation unit 104 calculates the maintained charging rate KSOC. Specifically, the charging rate calculation unit 104 calculates the charging rate SOC calculated in step S110 as the maintained charging rate KSOC. After executing the process of step S120, the charging rate calculation unit 104 temporarily ends the series of processes of the charging rate calculation process. Then, the charging rate calculation unit 104 executes the process of step S10 again.

[0055] On the other hand, in step S10, when the abnormal flag FC is enabled (ON) (step S10: Yes), the charging rate calculation unit 104 advances the process to step S20. In step S20, the charging rate calculation unit 104 calculates the maintained charging rate KSOC maintained at the time of executing step S20 as the latest maintained charging rate KSOC. After executing the process of step S20, the charging rate calculation unit 104 temporarily ends the series of processes of the charging rate calculation process. Then, the charging rate calculation unit 104 executes the process of step S10 again.

[0056] Next, the pre-charge processing performed by the pre-charge execution unit 106 is described. The pre-charge execution unit 106 performs the pre-charge processing only once from the time when the ignition switch G is turned on to the time when it is turned off. It should be noted that during the period when the pre-charge execution unit 106 is performing the pre-charge processing, the control performed by the pre-charge execution unit 106 takes precedence over the control performed by other functional units with respect to the control of the power supply circuit 16. In addition, at the time when the ignition switch G is turned on, the positive relay 35 and the negative relay 36 are in the disconnected state.

[0057] When the ignition switch G is turned on, the pre-charge execution unit 106 starts the pre-charge process. Figure 4 As shown, after the precharge execution unit 106 starts the precharge process, it executes the process of step S200. In step S200, the precharge execution unit 106 prohibits switching to the connection state of the positive electrode relay 35 and the negative electrode relay 36. That is, the disconnection state of the positive electrode relay 35 and the negative electrode relay 36 is maintained. Thereafter, the precharge execution unit 106 advances the process to step S210.

[0058] In step S210, the precharge execution unit 106 determines whether the acquisition abnormality flag FC is enabled (ON). When the acquisition abnormality flag FC is off (step S210: No), the precharge execution unit 106 advances the process to step S300.

[0059] In step S300, the precharge execution unit 106 calculates the target voltage range VZ based on the battery output voltage VB detected by the first battery voltage sensor 24. Specifically, the precharge execution unit 106 obtains the latest battery output voltage VB. Then, the precharge execution unit 106 calculates the value obtained by subtracting the tolerable differential voltage VP from the battery output voltage VB as the lower limit value of the target voltage range VZ. In addition, the precharge execution unit 106 calculates the value obtained by adding the tolerable differential voltage VP to the battery output voltage VB as the upper limit value of the target voltage range VZ. The precharge execution unit 106 stores the tolerable differential voltage VP in advance. The tolerable differential voltage VP is related to the voltage difference between the first battery 22 and the first capacitor 41, and is predetermined by experiments and simulations as the voltage difference at which the positive relay 35 and the negative relay 36 are not welded when the positive relay 35 and the negative relay 36 are set to a connected state. After executing the process of step S300 , the precharge execution unit 106 advances the process to step S240 .

[0060] On the other hand, when the pre-charge execution unit 106 obtains the abnormal flag FC as enabled (ON) in step S210 (step S210: Yes), the processing proceeds to step S220. In step S220, the pre-charge execution unit 106 calculates the estimated output voltage EVB of the first battery 22 based on the maintained charging rate KSOC. Here, the pre-charge execution unit 106 pre-stores a characteristic map representing the relationship between the charging rate SOC of the first battery 22 and the open circuit voltage OCV of the first battery 22. The open circuit voltage OCV of the first battery 22 refers to the output voltage of the first battery 22 in a state where no charge or discharge current flows through the first battery 22. The above-mentioned characteristic map representing the relationship between the charging rate SOC of the first battery 22 and the open circuit voltage OCV of the first battery 22 is determined for each product of the first battery 22. The characteristic map is prepared based on experiments, simulations, etc. As Figure 3 As shown in the characteristic map, generally, the larger the charge rate SOC is, the larger the open circuit voltage OCV is.

[0061] When calculating the estimated output voltage EVB, the pre-charge execution unit 106 first obtains the latest maintained charge rate KSOC calculated by the charge rate calculation unit 104. In addition, the charge rate calculation unit 104 refers to the characteristic map. Then, the charge rate calculation unit 104 calculates the open circuit voltage OCV corresponding to the maintained charge rate KSOC in the characteristic map as the estimated output voltage EVB. Figure 4 After the process of step S220 shown, the process proceeds to step S230.

[0062] In step S230, the precharge execution unit 106 calculates the target voltage range VZ based on the estimated output voltage EVB. Specifically, the precharge execution unit 106 calculates the value obtained by subtracting the allowable differential voltage VP from the estimated output voltage EVB as the lower limit value of the target voltage range VZ. In addition, the precharge execution unit 106 calculates the value obtained by adding the allowable differential voltage VP to the estimated output voltage EVB as the upper limit value of the target voltage range VZ. After executing the processing of step S230, the precharge execution unit 106 enters the processing into step S240. It should be noted that the processing of steps S220, S230, and S300 is a target calculation processing.

[0063] In step S240, the precharge execution unit 106 starts boosting the bidirectional converter 50. Thereafter, the precharge execution unit 106 advances the process to step S250.

[0064] In step S250, the precharge execution unit 106 determines whether the converter output voltage VD detected by the converter voltage sensor 52 is a value within the target voltage range VZ. Specifically, the precharge execution unit 106 obtains the latest converter output voltage VD. Then, the precharge execution unit 106 compares the converter output voltage VD with the lower limit value and the upper limit value of the target voltage range VZ. When the converter output voltage VD is a value that deviates from the target voltage range VZ (step S250: No), the precharge execution unit 106 performs the processing of step S250 again. The precharge execution unit 106 repeatedly performs the processing of step S250 until the converter output voltage VD becomes a value within the target voltage range VZ. Then, after the converter output voltage VD becomes a value within the target voltage range VZ (step S250: Yes), the precharge execution unit 106 enters the processing into step S260.

[0065] In step S260, the precharge execution unit 106 stops the voltage boosting drive of the bidirectional converter 50. Thereafter, the precharge execution unit 106 advances the process to step S270.

[0066] In step S270, the precharge execution unit 106 switches the positive electrode relay 35 and the negative electrode relay 36 to the connection state. Then, the precharge execution unit 106 ends the series of precharge processing.

[0067] Next, the operation of this embodiment will be described.

[0068] Assume that at time T1, the vehicle 10 is traveling. Figure 5 As shown in (b), both the positive relay 35 and the negative relay 36 are in the connected state. In addition, it is assumed that no acquisition abnormality occurs at time T1. Figure 5 As shown in (d), the acquisition exception flag FC is turned off (OFF), and as Figure 5 As shown in (c) of FIG. 1 , the charge / discharge prohibition flag FN is also OFF. That is, the motor generator 14 is in the driving state.

[0069] Assume that an acquisition anomaly occurs at time T2 after time T1. In this case, Figure 5 As shown in (d) of FIG. 1 , the abnormal flag FC is switched to enable (ON). At the same time, Figure 5As shown in (c), the charge and discharge prohibition flag FN is switched to ON, and the motor generator 14 is set to a non-driving state. Thereafter, the vehicle 10 travels using only the output of the internal combustion engine 12. In addition, when the abnormality flag FC is switched to ON at time T2, the charge rate LSOC before the abnormality occurs is calculated as the maintained charge rate KSOC. The charge rate LSOC before the abnormality occurs is the charge rate SOC of the first battery 22 calculated at the last timing before the abnormality flag FC is switched to ON.

[0070] like Figure 5 As shown in (a), it is assumed that the ignition switch G is turned off at time T3 after time T2. Figure 5 As shown in (b), the positive relay 35 and the negative relay 36 are switched to the disconnected state. Assuming that at the subsequent time T4, as Figure 5 As shown in (a), the ignition switch G is turned on again. Then, assume that the acquisition abnormality continues to occur after this time T4. In this case, Figure 5 As shown in (e), after time T4, the charge rate LSOC before the abnormality occurs is also calculated as the maintenance charge rate KSOC.

[0071] In addition, when the ignition switch G is turned on at time T4, the target voltage range VZ is calculated to start the pre-charging process. Since the acquisition abnormality is occurring, the target voltage range VZ is calculated based on the estimated output voltage EVB based on the maintained charging rate KSOC. The estimated output voltage EVB is the open circuit voltage of the first battery 22 immediately before the acquisition abnormality occurs. Here, since the electric generator 14 is set to a non-driving state at time T2 when the acquisition abnormality occurs, the open circuit voltage OCV of the first battery 22 is maintained at a value substantially the same as the value at time T2 when the acquisition abnormality occurs during the period from time T2 to time T4. Therefore, the open circuit voltage POCV during the pre-charging process is the above-mentioned estimated output voltage EVB.

[0072] After the target voltage range VZ is calculated, the boost drive of the bidirectional converter 50 is started. Figure 5 As shown in (f) of FIG. 1 , as the ignition switch G is turned off at time T3, the converter output voltage VD decreases to zero before time T4. Then, when the bidirectional converter 50 is boosted from time T4 as described above, the converter output voltage VD increases from zero. When the converter output voltage VD reaches a value within the target voltage range VZ at time T5, the boosting of the bidirectional converter 50 is stopped. Then, as shown in FIG. Figure 5 As shown in (b) of FIG. 1 , the positive electrode relay 35 and the negative electrode relay 36 are switched to a connected state.

[0073] Next, the effects of this embodiment will be described.

[0074] (1) In the above configuration, the estimated output voltage EVB of the first battery 22 before the acquisition abnormality occurs is used for the calculation of the target voltage range VZ. Here, at the timing before the acquisition abnormality occurs, the positive relay 35 and the negative relay 36 are in a connected state. Therefore, the first battery 22 is electrically connected to the load 18, and power is transferred between the first battery 22 and the load 18. When power is transferred between the first battery 22 and the load 18, the battery output voltage VB detected by the first battery voltage sensor 24 fluctuates up and down relative to the open circuit voltage OCV of the first battery 22. When such an output voltage including a fluctuation amount relative to the open circuit voltage OCV is applied to the calculation of the target voltage range VZ, it is difficult to determine the target voltage range VZ as an appropriate value.

[0075] In contrast, the charge rate SOC of the first battery 22 becomes a value corresponding to the open circuit voltage OCV, regardless of the exchange of power between the first battery 22 and the load 18. Therefore, the open circuit voltage OCV of the first battery 22 before the acquisition abnormality occurs can be calculated based on the charge rate SOC of the first battery 22 as the above-mentioned estimated output voltage EVB. Moreover, in the above-mentioned configuration, the estimated output voltage EVB is calculated based on the charge rate SOC of the first battery 22 calculated at the last timing before the acquisition abnormality occurs. Therefore, the open circuit voltage OCV of the first battery 22 at the timing immediately before the acquisition abnormality occurs can be calculated as the estimated output voltage EVB. By calculating the target voltage range VZ based on such an estimated output voltage EVB, the target voltage range VZ can be appropriately determined. Moreover, by determining the target voltage range VZ, the pre-charging process can be performed even when an acquisition abnormality occurs.

[0076] (2) In the above configuration, when an acquisition abnormality occurs, the charging and discharging of the first battery 22 is prohibited. Therefore, as described in the above action, during the period from the occurrence of the acquisition abnormality to the execution of the pre-charging process, the open circuit voltage OCV of the first battery 22 is maintained at a value substantially the same as the value immediately before the acquisition abnormality occurs. That is, the change in the open circuit voltage OCV of the first battery 22 during the period from the occurrence of the acquisition abnormality to the execution of the pre-charging process is suppressed. In addition, the possibility that the estimated output voltage EVB based on the charging rate SOC immediately before the acquisition abnormality occurs is consistent with the open circuit voltage OCV of the first battery 22 when the pre-charging process is actually performed increases. By determining the target voltage range VZ based on such an estimated output voltage EVB, the target voltage range VZ can be determined using a value substantially the same as the case where the battery output voltage VB can be obtained from the first battery voltage sensor 24 as an input.

[0077] It should be noted that the present embodiment can be implemented by modification as follows. The present embodiment and the following modification examples can be implemented in combination with each other within the scope of no technical contradiction.

[0078] The method for calculating the target voltage range VZ is not limited to the example of the above embodiment. For example, the allowable differential voltage VP for calculating the lower limit value of the target voltage range VZ and the allowable differential voltage VP for calculating the upper limit value of the target voltage range VZ may be set to different values. In this case, the allowable differential voltage VP for calculating the lower limit value and the allowable differential voltage VP for calculating the upper limit value may be appropriately determined so that welding does not occur in the positive electrode relay 35 and the negative electrode relay 36.

[0079] The allowable differential voltage VP is not limited to welding, and may be a value that does not allow a current large enough to cause abnormality in the operation of the positive electrode relay 35 and the negative electrode relay 36 to flow when the positive electrode relay 35 and the negative electrode relay 36 are in the connected state.

[0080] The permissible differential voltage VP may be set to zero if relays capable of withstanding high voltage and high current are used as the positive electrode relay 35 and the negative electrode relay 36. In this case, the target voltage range VZ may also be a specific value, not a constant width.

[0081] The method for determining the end of the boost drive of the bidirectional converter 50 is not limited to the example of the above embodiment. For example, it is also possible to determine whether the first charging voltage VC1 detected by the first capacitor voltage sensor 43 is within the target voltage range VZ. It is also possible to determine whether the second charging voltage VC2 detected by the second capacitor voltage sensor 63 is within the target voltage range VZ. In order to prevent erroneous determination, it is also possible to determine whether more than one of the converter output voltage VD, the first charging voltage VC1, and the second charging voltage VC2 is within the target voltage range VZ, instead of using only one of the converter output voltage VD, the first charging voltage VC1, and the second charging voltage VC2.

[0082] The calculation method of the maintained charge rate KSOC is not limited to the example of the above-mentioned embodiment. The calculation method of the maintained charge rate KSOC can be configured to calculate the charge rate SOC of the first battery 22 calculated at the timing before the acquisition abnormality occurs as the maintained charge rate KSOC after the acquisition abnormality occurs. For example, after the acquisition abnormality occurs, the maintained charge rate KSOC can be directly stored after the maintained charge rate KSOC is calculated once, instead of repeatedly calculating the maintained charge rate KSOC as in the above-mentioned embodiment.

[0083] The charge rate KSOC to be maintained calculated after the acquisition abnormality occurs may not be the charge rate SOC of the first battery 22 calculated last among the charge rates SOC of the first battery 22 calculated before the acquisition abnormality occurs. If the charge rate SOC of the first battery 22 is calculated at a timing close to the acquisition abnormality, it will not change much compared with the charge rate SOC of the first battery 22 calculated last.

[0084] The calculation of the maintained charge rate KSOC may be omitted when no acquisition abnormality occurs.

[0085] The characteristic map is not limited to a table or a graph, but may be a formula.

[0086] The method for calculating the charge rate SOC of the first battery 22 is not limited to the example of the above embodiment. For example, when the absolute value of the charge and discharge current AB of the first battery 22 is small, the charge rate SOC of the first battery 22 may be calculated using the battery output voltage VB detected by the first battery voltage sensor 24. Specifically, when calculating the charge rate SOC of the first battery 22, the charge rate SOC corresponding to the battery output voltage VB in the characteristic map may be calculated with reference to the characteristic map.

[0087] ·It is not essential to provide the charge and discharge determination unit 108. When the charge and discharge determination unit 108 is abolished, the charge and discharge of the first battery 22 is allowed after the timing when the acquisition abnormality occurs. In this case, if the charge rate SOC of the first battery 22 calculated at the timing before the acquisition abnormality occurs is calculated as the maintained charge rate KSOC, the open circuit voltage of the first battery 22 before the acquisition abnormality occurs can be calculated based on the maintained charge rate KSOC. It is preferable to calculate the target voltage range VZ based on the open circuit voltage in terms of determining the target voltage range VZ to an appropriate value.

[0088] If the configuration of prohibiting the charging and discharging of the first battery when an acquisition abnormality occurs is eliminated as in the above-mentioned modification example, the charging rate calculation process and the pre-charging process of the above-mentioned embodiment can also be applied to an electric vehicle without an internal combustion engine.

[0089] The vehicle control device 100 may be composed of a plurality of control devices. Furthermore, each functional part such as the charging rate calculation unit 104 may be provided as a plurality of control devices instead of being integrated into a single control device. In this case, information can be transmitted and received between the plurality of control devices.

[0090] When the vehicle control device 100 is composed of a plurality of control devices as in the above-mentioned modification example, one functional unit may be provided across the plurality of control devices. For example, regarding the charging rate calculation unit, the control unit that calculates the charging rate SOC of the first battery 22 and the control unit that calculates the maintained charging rate KSOC may be separated from each other. In this case, the charging rate calculation unit 104 is composed of these two control devices.

[0091] The target calculation unit may be a functional unit different from the precharge execution unit 106 .

[0092] The configuration of the power supply circuit 16 is not limited to the example of the above-described embodiment. For example, if the first charging voltage VC1 detected by the first capacitor voltage sensor 43 is used to determine the end of the boost drive of the bidirectional converter 50 instead of the converter output voltage VD detected by the converter voltage sensor 52, the converter voltage sensor 52 may be eliminated.

[0093] The configuration of the load 18 is not limited to the example of the above-described embodiment. For example, the load may be configured by only the motor generator 14 and the inverter 90 .

[0094] The number of the motor generators 14 may be changed as appropriate.

Claims

1. A control device for a power supply circuit, the power supply circuit comprising: a first battery; a voltage sensor configured to detect an output voltage of the first battery; a relay configured to cut off / make an electrical connection from the first battery to a load; a second battery, wherein a rated voltage of the second battery is lower than a rated voltage of the first battery; and a converter configured to boost the output voltage of the second battery and output the boosted output voltage to a portion between the relay and the load, The control device comprises a processing circuit, The processing circuit is configured to perform a pre-charging process in which the converter is boosted and driven until the output voltage of the converter reaches a value within a target voltage range determined based on the output voltage of the first battery in a state in which the electrical connection between the first battery and the load is cut off by the relay. The processing circuit has: a charging rate calculation unit configured to calculate the charging rate of the first battery; and a target calculation unit configured to calculate the target voltage range, The charging rate calculation unit is configured to: in the case of an acquisition abnormality that makes it impossible to acquire the output voltage of the first battery detected by the voltage sensor, calculate the charging rate of the first battery calculated at a timing before the acquisition abnormality occurs as a maintained charging rate after the timing when the acquisition abnormality occurs, The target calculation unit is configured to calculate an estimated output voltage of the first battery based on the maintained charging rate and calculate the target voltage range based on the estimated output voltage when the precharge process is executed in a state where the acquisition abnormality is occurring.

2. The control device for a power supply circuit according to claim 1, wherein: The charging rate calculation unit is configured to calculate, when the acquisition abnormality occurs, a charging rate of the first battery that is calculated last among charging rates of the first battery calculated before the acquisition abnormality occurs as the maintained charging rate.

3. The control device for a power supply circuit according to claim 1 or 2, wherein: The processing circuit includes a charge / discharge determination unit for determining whether the first battery can be charged or discharged. The charge and discharge determination unit is configured to prohibit charge and discharge of the first battery when the acquisition abnormality occurs.

4. A non-transitory computer-readable storage medium storing a power supply circuit control program, the power supply circuit control program, when executed by a processing circuit of a control device of a power supply circuit having a first battery, a voltage sensor configured to detect an output voltage of the first battery, a relay configured to cut off / make electrical connection from the first battery to a load, a second battery having a rated voltage lower than the rated voltage of the first battery, and a converter configured to boost the output voltage of the second battery and output the boosted output voltage to a portion between the relay and the load, causing the processing circuit to execute: a pre-charging process of performing a voltage-boosting drive of the converter until the output voltage of the converter reaches a value within a target voltage range determined based on the output voltage of the first battery, in a state where the electrical connection between the first battery and the load is cut off by the relay; A charging rate calculation process, calculating the charging rate of the first battery; as well as Target calculation processing, calculating the target voltage range, The charging rate calculation process includes the following process: in the case where an acquisition abnormality occurs that makes it impossible to acquire the output voltage of the first battery detected by the voltage sensor, after the timing when the acquisition abnormality occurs, calculating the charging rate of the first battery calculated at the timing before the acquisition abnormality occurs as a maintained charging rate, The target calculation process includes the following process: when the precharge process is executed in a state where the acquisition abnormality is occurring, an estimated output voltage of the first battery is calculated based on the maintained charge rate, and the target voltage range is calculated based on the estimated output voltage.

5. A control method for a power supply circuit, the power supply circuit comprising: a first battery; a voltage sensor configured to detect an output voltage of the first battery; a relay configured to cut off / make an electrical connection from the first battery to a load; a second battery, wherein a rated voltage of the second battery is lower than a rated voltage of the first battery; and a converter configured to boost the output voltage of the second battery and output the boosted output voltage to a portion between the relay and the load, the control method comprising: executing a pre-charging process, the pre-charging process being a process of boosting the converter until the output voltage of the converter reaches a value within a target voltage range determined based on the output voltage of the first battery, in a state where the electrical connection between the first battery and the load is cut off by the relay; executing a charging rate calculation process of calculating a charging rate of the first battery; and executing a target calculation process, the target calculation process being a process of calculating the target voltage range, The charging rate calculation process includes the following process: in the case where an acquisition abnormality occurs that makes it impossible to acquire the output voltage of the first battery detected by the voltage sensor, after the timing when the acquisition abnormality occurs, calculating the charging rate of the first battery calculated at the timing before the acquisition abnormality occurs as a maintained charging rate, The target calculation process includes the following process: when the precharge process is executed in a state where the acquisition abnormality is occurring, an estimated output voltage of the first battery is calculated based on the maintained charge rate, and the target voltage range is calculated based on the estimated output voltage.

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