JP7435206B2 - Power circuit control device - Google Patents

Description

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

The power system disclosed in Patent Document 1 includes a first battery configured with a secondary battery. An electric load is connected to the first battery via a relay that connects and disconnects electrical connection. The power system also includes a second battery having a lower rated voltage than the first battery. A converter that boosts the output voltage of the second battery is connected to the second battery. The converter is connected to a part closer to the electrical load than the relay, and supplies a boosted voltage to the electrical load.

Prior to starting power supply from the first battery to the electrical load, the control device of the power system performs a precharging process with the electrical connection between the first battery and the electrical load cut off by the relay. In this precharge process, the converter is boosted until the voltage of the power supplied from the converter to the electrical load becomes approximately equal to a target voltage determined as the output voltage of the first battery.

JP2008-289326A

In a control device such as the technique disclosed in Patent Document 1, there is an upper circuit for commands that sets a target voltage and instructs boost drive of the converter, and a lower circuit for the converter that receives the target voltage and actually controls boost drive of the converter. may be provided separately.

Here, an acquisition abnormality may occur in which the lower-level circuit cannot acquire the target voltage set by the higher-level circuit. When performing precharge processing under a situation where such an acquisition abnormality has occurred, the lower circuit automatically determines whether the output voltage of the converter has reached the target voltage, that is, the timing to end boost drive of the converter. Cannot be determined. Therefore, in order to deal with such a situation, it is conceivable that the upper circuit that can grasp the target voltage determines the completion of the precharge process and outputs a boost drive stop signal to the lower circuit. However, there is a considerable delay between when the upper circuit outputs the stop signal and when the lower circuit receives the signal and actually stops the boost drive of the converter. Therefore, there is a possibility that the converter continues to boost the voltage during the delay, and the voltage supplied from the converter to the electrical load greatly exceeds the target voltage.

A power supply circuit control device for solving the above problem includes a first battery, a relay that connects and disconnects electrical connection from the first battery to a load, and a second battery having a lower rated voltage than the first battery. is applied to a power supply circuit having a converter that boosts the output voltage of the second battery and outputs it to the load side rather than the relay, and the electrical connection between the first battery and the load is applied by the relay. The control device executes a precharge process in which the converter is boosted 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 while the connection is cut off. and a converter control unit that obtains the target voltage range from the precharge management unit and boosts the converter toward the target voltage range. , when performing the precharge processing in a situation where an acquisition abnormality occurs in which the converter control unit cannot acquire the target voltage range, the converter control unit may perform step-up driving of the converter so that the output voltage of the converter is within the first range. The precharge control unit increases the amount of voltage boost per unit time by the converter until it reaches a changed voltage that is determined as a voltage lower than the output voltage of the battery than after reaching the changed voltage, and the precharge control section When the output voltage of the converter reaches a value within the target voltage range, a stop signal for stopping boost drive of the converter is output to the converter control section.

According to the above configuration, immediately before the output voltage of the converter falls within the target voltage range, the amount of voltage boost per unit time by the converter is relatively small. Therefore, even if there is a delay between when the converter's output voltage falls within the target voltage range and when it receives a stop signal from the precharge general unit and stops boosting, the converter's output voltage falls within the target voltage range. It will not be boosted significantly beyond that. Furthermore, according to the above configuration, the amount of boost per unit time by the converter is relatively large until the output voltage of the converter reaches the changed voltage. Therefore, the time required to boost the output voltage of the converter to within the target voltage range does not become excessively long.

A schematic configuration diagram of a vehicle power system. 5 is a flowchart showing the processing procedure of precharge processing for normal times. 5 is a flowchart showing the processing procedure of precharge processing for when an abnormality occurs. 5 is a time chart showing an example of changes over time in each parameter related to precharge processing for when an abnormality occurs.

Hereinafter, one embodiment of a power supply circuit control device will be described with reference to the drawings.
First, the schematic configuration of the electric power system installed in the vehicle will be explained.
As shown in FIG. 1, a hybrid vehicle (hereinafter simply referred to as a vehicle) 10 is equipped with an internal combustion engine 12 that serves as a drive source for the vehicle 10. As shown in FIG. Furthermore, the vehicle 10 is equipped with a motor generator 14 that serves as a starting source separate from the internal combustion engine 12. The motor generator 14 has the functions of both a motor and a generator.

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

The first battery 22 is connected via a pair of power lines to a buck-boost converter 80 that boosts and lowers the voltage and outputs the voltage. Specifically, the positive terminal of the first battery 22 is connected to the buck-boost converter 80 via the first positive line 31. Further, the negative terminal of the first battery 22 is connected to the buck-boost converter 80 via the first negative line 32 .

A current sensor 26 that detects the charging/discharging current AB flowing through the first battery 22 is attached in the middle of the first positive electrode line 31 . In this embodiment, the charging/discharging current AB is detected as a positive value when the first battery 22 is being discharged, and as a negative value when being charged.

A positive relay 35 that connects and disconnects the electrical connection between the first battery 22 and the buck-boost converter 80 is attached to a portion of the first positive line 31 closer to the buck-boost converter 80 than the current sensor 26 . Further, a negative relay 36 is installed midway along the first negative line 32 to connect and disconnect the electrical connection between the first battery 22 and the buck-boost converter 80. When the positive relay 35 and the negative relay 36 are switched to the cutoff state, the electrical connection between the first battery 22 and the buck-boost converter 80 is turned off. 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 turned on.

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

Although detailed illustrations are omitted, the bidirectional converter 50 is configured to include a plurality of transistors 50T as switching elements and a freewheeling diode 50D connected in parallel to the transistors 50T, and increases or decreases the voltage and outputs it. do. Specifically, bidirectional converter 50 boosts the output voltage of second battery 29 and outputs it to first positive line 31 and first negative line 32 . Further, the bidirectional converter 50 steps down the voltages of the first positive line 31 and the first negative line 32 and outputs the voltages to the second battery 29 . A converter voltage sensor 52 is connected to the bidirectional converter 50 to detect the output voltage from the bidirectional converter 50 to the first positive line 31 and the first negative line 32 as a converter output voltage VD.

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

A first capacitor 41 that smoothes 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 closer to the buck-boost converter 80 than the connection point of the bidirectional converter 50, and to a portion of the first negative line 32 that is closer to the buck-boost converter 80 than the connection point of the bidirectional converter 50. It is also connected to the part on the buck-boost converter 80 side. A first capacitor voltage sensor 43 that detects the charging voltage VC1 of the first capacitor 41 is connected between the terminals of the first capacitor 41.

In the buck-boost converter 80 described above, the first transistor 81 and the second transistor 82, which are 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 freewheeling is connected in parallel to the first transistor 81 . A second diode 86 for freewheeling is connected in parallel to the second transistor 82 .

The first positive line 31 is connected to the connection point between the emitter terminal of the first transistor 81 and the collector terminal of the second transistor 82 via a reactor 88 . An inverter 90 is connected to the collector terminal of the first transistor 81 via a second positive line 71. The emitter terminal of the second transistor 82 is connected to the first negative line 32 and also to the inverter 90 via the second negative line 72 . Inverter 90 is connected to motor generator 14 . Although not shown, a control voltage for switching on/off of these transistors is input to the base terminal of the first transistor 81 and the base terminal of the second transistor 82. Inverter 90 converts DC power and AC power between buck-boost converter 80 and motor generator 14 .

A second capacitor 61 that smoothes the voltage between the buck-boost 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 that detects the charging voltage VC2 of the second capacitor 61 is connected between the terminals of the second capacitor 61.

In this embodiment, an electrical load (hereinafter simply referred to as load) 18 includes a motor generator 14, an inverter 90, and a step-up/step-down converter 80. 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.

Next, the control configuration of the vehicle 10 will be explained.
The vehicle 10 is equipped with a vehicle control device 100 that controls various parts of the vehicle 10 including the electric power system. Further, the vehicle 10 is equipped with a converter control device 200 that controls the bidirectional converter 50. Converter control device 200 is a control device dedicated to bidirectional converter 50. Vehicle control device 100 is a higher level control device with respect to converter control device 200, and controls bidirectional converter 50 by controlling converter control device 200. These vehicle control device 100 and converter control device 200 constitute a power supply control device 11 that controls a power supply circuit 16. Converter control device 200 constitutes a converter control section that controls bidirectional converter 50 in power supply control device 11 .

Vehicle control device 100 and converter control device 200 may be configured as one or more processors that execute various processes according to computer programs (software). Note that the vehicle control device 100 and the converter control device 200 are one or more dedicated hardware circuits such as an application-specific integrated circuit (ASIC), or a combination thereof, which executes at least some of the various processes. It may be configured as a circuit including. The processor includes a CPU and memory such as RAM and ROM. The memory stores program codes or instructions configured to cause the CPU to perform processes. Memory or computer-readable media includes any available media that can be accessed by a general purpose or special purpose computer.

Detection signals from various sensors attached to the vehicle 10 are input to the vehicle control device 100 . Specifically, the following detection signals are input to the vehicle control device 100.
- Output voltage VB of the first battery 22 detected by the first battery voltage sensor 24
- Charging and discharging current AB of the first battery 22 detected by the current sensor 26
-Charging voltage VC1 of the first capacitor 41 detected by the first capacitor voltage sensor 43
-Charging voltage VC2 of the second capacitor 61 detected by the second capacitor voltage sensor 63
Further, a signal related to converter output voltage VD detected by converter voltage sensor 52 is input to converter control device 200 .

Vehicle control device 100 and converter control device 200 are connected via CAN communication line 300. Vehicle control device 100 and converter control device 200 basically exchange signals related to various information via this CAN communication line 300. Further, vehicle control device 100 and converter control device 200 are connected by a power line 310 that directly connects these two control devices. Vehicle control device 100 outputs a pulse signal, which is a repeating signal of HIGH and LOW, to converter control device 200 via Zika line 310 . Vehicle control device 100 can change the duty ratio of the pulse signal depending on the type of command output to converter control device 200.

Here, due to an abnormality in CAN communication line 300 or the like, signals may not be exchanged between vehicle control device 100 and converter control device 200 via CAN communication line 300. Vehicle control device 100 includes an abnormality determination unit 102 that determines whether an acquisition abnormality has occurred in which vehicle control device 100 and converter control device 200 cannot acquire signals from each other via CAN communication line 300. Note that a situation where an acquisition abnormality has occurred is a situation where converter control device 200 is unable to obtain a target voltage range VZ, which will be described later, from vehicle control device 100.

Now, 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 connected state, and power supply from the first battery 22 to the buck-boost converter 80 is started. At this time, if a large current instantaneously flows from the high voltage first battery 22 to the buck-boost converter 80, there is a risk that the positive relay 35 and the negative relay 36 may be welded together. Therefore, before starting power supply from the first battery 22 to the buck-boost converter 80, the first capacitor 41 is charged while the electrical connection between the first battery 22 and the buck-boost converter 80 is cut off. processing is required. By charging the first capacitor 41, 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 a small value.

The vehicle control device 100 includes a precharge control unit 104 that controls a precharge process that is a process of charging the first capacitor 41. In this precharge process, the positive relay 35 and the negative relay 36 are maintained in a cut-off state until the converter output voltage VD reaches a value within the target voltage range VZ determined based on the output voltage VB of the first battery 22. Bidirectional converter 50 is boosted. Note that during the execution of the precharge process, the charging voltage VC1 of the first capacitor 41 becomes approximately the same as the converter output voltage VD. Furthermore, when performing the precharge process, both the buck-boost converter 80 and the inverter 90 are in a non-driven 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 VC2 of the second capacitor 61 becomes substantially the same as the converter output voltage VD. Therefore, in the precharge process, the charging voltage VC1 of the first capacitor 41 and the charging voltage VC2 of the second capacitor 61 increase to the target voltage range VZ.

The precharge control unit 104 can execute precharge base processing, which is the base processing of precharge processing. In the precharge base process, the precharge control unit 104 calculates the target voltage range VZ. Furthermore, in the precharge-based process, precharge control unit 104 outputs a command signal to converter control device 200 to cause converter control device 200 to execute boost drive of bidirectional converter 50 .

When performing precharge base processing in a situation where no acquisition abnormality has occurred, precharge control unit 104 uses target voltage range VZ as a command signal for causing converter control device 200 to perform boost drive on bidirectional converter 50. Output. Precharge control unit 104 outputs target voltage range VZ via CAN communication line 300. On the other hand, when precharge base processing is performed in a situation where an acquisition abnormality has occurred, precharge control unit 104 causes converter control device 200 to perform step-up drive of bidirectional converter 50 via Zika line 310. An abnormality execution signal D1, which is a command signal, is output.

When performing precharge-based processing in a situation where no acquisition abnormality has occurred, the precharge control unit 104 instructs the converter control device 200 to determine whether the bidirectional converter 50 has completed boosting, that is, the charging of the first capacitor 41 has been completed. entrust. On the other hand, when performing precharge processing under a situation where an acquisition abnormality has occurred, the precharge control unit 104 determines by itself whether the boosting by the bidirectional converter 50 is complete. Then, when the charging voltage VC1 of the first capacitor 41 reaches a value within the target voltage range VZ, the precharge control section 104 sends a command signal to the converter control device 200 to stop the boost drive of the bidirectional converter 50. A stop signal D2 is output when a certain abnormality occurs. The precharge control unit 104 outputs an abnormality stop signal D2 via the Zika line 310. Note that, as described above, during the precharge process, the charging voltage VC1 of the first capacitor 41 and the converter output voltage VD substantially match. Therefore, the charging voltage VC1 of the first capacitor 41 having a value within the target voltage range VZ corresponds to converter output voltage VD having a value within the target voltage range VZ.

Converter control device 200 is capable of executing a boost drive process that is a process of boosting bidirectional converter 50 in response to a command signal output by precharge control unit 104 . When performing boost drive processing in a situation where no acquisition abnormality has occurred, converter control device 200 acquires the target voltage range VZ output from precharge control section 104 and operates the bidirectional converter toward the target voltage range VZ. 50 boost drive is performed. In this case, converter control device 200 maintains the amount of boost per unit time (hereinafter simply referred to as boost amount) by bidirectional converter 50 constant from the start to the end of the boost drive.

On the other hand, when converter control device 200 performs boost drive processing under a situation where an acquisition abnormality has occurred, when boosting drive of bidirectional converter 50, converter output voltage VD reaches a predetermined change voltage VK. In this case, the boost amount by the bidirectional converter 50 is made larger than after reaching the modified voltage VK.

Next, a process for determining whether there is an acquisition abnormality, which is executed by the abnormality determining unit 102 of the vehicle control device 100, will be described. The abnormality determination unit 102 repeats the process of determining the presence or absence of an acquisition abnormality from when the ignition switch G is turned on until it is turned off. Note that, as a premise of this process, converter control device 200 repeatedly outputs determination parameters for determining the presence or absence of acquisition abnormality to vehicle control device 100 via CAN communication line 300. Then, the abnormality determination unit 102 of the vehicle control device 100 repeatedly receives the determination parameters. In this embodiment, the determination parameter is converter output voltage VD.

Abnormality determination unit 102 determines that an acquisition abnormality has occurred when a determination condition that a situation in which converter output voltage VD cannot be acquired from converter control device 200 continues for a predetermined period of time or more is satisfied. The predetermined time is determined to be sufficiently longer than the acceptance cycle of the converter output voltage VD in the abnormality determining section 102. Incidentally, a situation in which the abnormality determination unit 102 cannot acquire the converter output voltage VD is, for example, when the CAN communication line 300 is disconnected or the connector of the CAN communication line 300 is disconnected from the input/output port of the vehicle control device 100 or the converter control device 200. This occurs when a communication failure occurs. Further, a situation in which the abnormality determining unit 102 cannot acquire the converter output voltage VD also occurs when an input/output port of the vehicle control device 100 or the converter control device 200 fails.

The abnormality determination unit 102 determines that no acquisition abnormality has occurred when the above determination conditions are not satisfied. When determining whether there is an acquisition abnormality, the abnormality determination unit 102 sets an acquisition abnormality occurrence flag FC indicating the determination result. When the abnormality determination unit 102 determines that an acquisition abnormality has occurred, it turns on the acquisition abnormality occurrence flag FC. When determining that an acquisition abnormality has not occurred, the abnormality determining unit 102 turns off the acquisition abnormality occurrence flag FC.

Next, details of the precharge base processing executed by precharge control section 104 of vehicle control device 100 and the boost drive processing executed by converter control device 200 in conjunction with the precharge base processing will be described. Here, the precharge base processing is the normal precharge base processing that is performed in a situation where no acquisition abnormality has occurred, and the precharge base processing for abnormality that is performed in a situation where an acquisition abnormality has occurred. The contents are different. The same applies to the boost drive process. Below, the precharge base processing and boost drive processing for normal times will be explained first, and then the precharge base processing and boost drive processing for when an abnormality occurs will be explained. It should be noted that, regardless of whether it is for normal times or when an abnormality occurs, the precharge base process and the boost drive process are executed only once from when the ignition switch G is turned on until it is turned off. Further, regarding the control related to the power supply circuit 16, the control by the precharge base process and the boost drive process is given priority over the control by other processes.

The precharge base processing for normal times will be explained. When the ignition switch G is turned on, the precharge control section 104 of the vehicle control device 100 starts the precharge base processing for normal times on the condition that the acquisition abnormality occurrence flag FC is off. Note that when the ignition switch G is turned on, the positive relay 35 and the negative relay 36 are in a cutoff state.

As shown in FIG. 2A, when the precharge control unit 104 starts the precharge base processing for normal times, it executes the processing of step S100. In step S100, the precharge control unit 104 prohibits switching of the positive relay 35 and the negative relay 36 to the connected state. That is, the precharge control unit 104 maintains the positive relay 35 and the negative relay 36 in a disconnected state. After executing the process in step S100, the precharge control unit 104 advances the process to step S110.

In step S110, the precharge control unit 104 calculates a target voltage range VZ. Specifically, the precharge control unit 104 obtains the latest output voltage VB of the first battery 22 detected by the first battery voltage sensor 24. The precharge control unit 104 then calculates the output voltage VB of the first battery 22 as the lower limit value of the target voltage range VZ. Further, the precharge control unit 104 calculates a value obtained by adding the tolerance voltage VP to the output voltage VB of the first battery 22 as the upper limit value of the target voltage range VZ. The precharge management unit 104 stores the tolerance voltage VP in advance. Here, regarding the voltage difference between the first battery 22 and the first capacitor 41, the limit value of the voltage difference at which the positive relay 35 and the negative relay 36 will not weld when the positive relay 35 and the negative relay 36 are connected is defined as the limit value of the voltage difference. Let the voltage be VPM. The tolerance voltage VP is determined through experiments and simulations to be a value slightly smaller than the limit voltage difference VPM. After executing the process of step S110, the precharge control unit 104 advances the process to step S120.

In step S120, precharge control section 104 outputs target voltage range VZ to converter control device 200 via CAN communication line 300. After this, the precharge control unit 104 advances the process to step S130.

In step S130, precharge control unit 104 determines whether a completion signal PE indicating that the bidirectional converter 50 has completed boosting is obtained. This completion signal PE is a signal output by converter control device 200 in normal boost drive processing, which will be described later. If the precharge control unit 104 has not acquired the completion signal PE (step S130: NO), it executes the process of step S130 again. The precharge control unit 104 repeats the process of step S130 until it obtains the completion signal PE. When the precharge control unit 104 obtains the completion signal PE (step S130: YES), it advances the process to step S140.

In step S140, the precharge control unit 104 switches the positive relay 35 and the negative relay 36 to a connected state. Then, the precharge control unit 104 ends the series of precharge base processing for normal times.

The boost drive process for normal times will be explained. As shown in FIG. 2B, converter control device 200 starts this process upon receiving the process of step S120 in the normal precharge base process. That is, converter control device 200 starts this process upon acquiring target voltage range VZ output by precharge control section 104.

When converter control device 200 starts the normal boost drive process, it executes the process of step S200. In step S200, converter control device 200 starts boosting drive of bidirectional converter 50. Converter control device 200 controls bidirectional converter 50 so that the amount of boost by bidirectional converter 50 becomes normal boost amount UN. Converter control device 200 substantially controls the switching frequency of transistor 50T of bidirectional converter 50 in accordance with the normal boost amount UN.

Converter control device 200 stores the normal boost amount UN in advance. The normal boost amount UN is determined by experiment or simulation in consideration of the processing process when stopping the boost drive of the bidirectional converter 50. Regarding the stop of the step-up drive, the first stop is the time required from when it is determined in step S210, which will be described later, that the step-up is completed by the bidirectional converter 50 until the switching of the bi-directional converter 50 actually stops after going through each process. Time. The normal boost amount UN is determined as a value slightly smaller than the value obtained by dividing the tolerance voltage VP used to calculate the target voltage range VZ by the first stop time. That is, the normal boost amount UN is set so that the amount of increase in the converter output voltage VD during the first stop time is smaller than the tolerance voltage VP.

After converter control device 200 executes the process of step S200, it advances the process to step S210. In step S210, converter control device 200 determines whether converter output voltage VD is a value within target voltage range VZ. Specifically, converter control device 200 acquires the latest converter output voltage VD detected by converter voltage sensor 52. Converter control device 200 then compares converter output voltage VD with the lower limit and upper limit of target voltage range VZ. Converter control device 200 executes the process of step S210 again when converter output voltage VD is a value outside the target voltage range VZ (step S210: NO). Converter control device 200 repeats the process of step S210 until converter output voltage VD reaches a value within target voltage range VZ. Then, when converter output voltage VD reaches a value within target voltage range VZ (step S210: YES), converter control device 200 advances the process to step S220.

In step S220, converter control device 200 stops boosting drive of bidirectional converter 50. Converter control device 200 then advances the process to step S230.

In step S230, converter control device 200 outputs completion signal PE indicating completion of boosting by bidirectional converter 50 to vehicle control device 100. After this, converter control device 200 ends a series of processes of the boost drive process for normal times. The series of processes related to the precharge base process for normal times and the series of processes related to the boost drive process for normal times described above constitute the precharge process for normal times.

Next, precharge-based processing for when an abnormality occurs will be explained. When the ignition switch G is turned on, the precharge control unit 104 of the vehicle control device 100 starts precharge base processing for when an abnormality occurs, provided that the acquisition abnormality flag FC is on. As described above, when the ignition switch G is turned on, the positive relay 35 and the negative relay 36 are in the cutoff state.

As shown in FIG. 3A, when the precharge control unit 104 starts the precharge base process for when an abnormality occurs, it executes the process of step S300. In step S300, the precharge control unit 104 prohibits switching of the positive relay 35 and the negative relay 36 to the connected state. Thereafter, the precharge control unit 104 advances the process to step S310.

In step S310, the precharge control unit 104 calculates the target voltage range VZ. The method for calculating the target voltage range VZ is the same as in the precharge-based processing for normal times, so a description thereof will be omitted. After executing the process of step S310, the precharge control unit 104 advances the process to step S320.

In step S320, the precharge control unit 104 starts outputting the abnormality execution signal D1, which instructs the bidirectional converter 50 to perform step-up driving, via the Zika line 310. The abnormality execution signal D1 is essentially a signal that instructs execution of the boost drive process for when an abnormality occurs. Thereafter, the precharge control unit 104 advances the process to step S330.

In step S330, the precharge control unit 104 determines whether the charging voltage VC1 of the first capacitor 41 is within the target voltage range VZ. Specifically, the precharge control unit 104 obtains the latest charging voltage VC1 of the first capacitor 41 detected by the first capacitor voltage sensor 43. The precharge control unit 104 then compares the charging voltage VC1 with the lower limit and upper limit of the target voltage range VZ. If the charging voltage VC1 is outside the target voltage range VZ (step S330: NO), the precharge control unit 104 executes the process of step S330 again. The precharge control unit 104 repeats the process of step S330 until the charging voltage VC1 reaches a value within the target voltage range VZ. Then, when the charging voltage VC1 reaches a value within the target voltage range VZ (step S330: YES), the precharge control unit 104 advances the process to step S340.

In step S340, the precharge control unit 104 starts outputting the abnormality stop signal D2, which instructs the bidirectional converter 50 to stop boosting drive, via the Zika line 310. Specifically, precharge control unit 104 switches the signal output to converter control device 200 via Zika line 310 from abnormality execution signal D1 to abnormality stop signal D2. The abnormality stop signal D2 is essentially a signal that instructs to stop execution of the boost drive process for when an abnormality occurs. After executing the process of step S340, the precharge control unit 104 advances the process to step S350.

In step S350, the precharge control unit 104 switches the positive relay 35 and the negative relay 36 to a connected state. Note that, as will be described later, there is a delay from when converter control device 200 acquires abnormality stop signal D2 outputted by precharge control unit 104 in step S340 until boost drive of bidirectional converter 50 actually stops. . On the other hand, there is a delay from when the precharge control unit 104 outputs a signal to switch the positive relay 35 and the negative relay 36 to the connected state in step S350 until the positive relay 35 and the negative relay 36 actually switch to the connected state. be. Due to the delay in switching between the positive relay 35 and the negative relay 36, the positive relay 35 and the negative relay 36 are switched to the connected state after the bidirectional converter 50 stops boosting the voltage. After executing the process of step S350, the precharge control unit 104 ends the series of processes of the precharge base process for when an abnormality occurs.

Note that the precharge control unit 104 continues to output the abnormality stop signal D2 started in step S340 until the ignition switch G is turned off. This abnormality stop signal D2 is also a signal that prohibits execution of the boost drive process for when an abnormality occurs. Here, if the acquisition abnormality occurrence flag FC is off when the ignition switch G is turned on and the precharge processing for normal times is to be performed, the precharge control unit 104 determines whether the ignition switch G is turned on. At the point in time, the output of the abnormality stop signal D2 is started to prohibit execution of the boost drive process for occurrence of an abnormality.

The boost drive process for when an abnormality occurs will be explained. As shown in FIG. 3B, converter control device 200 starts this process upon receiving the process of step S320 in the precharge base process for when an abnormality occurs. That is, converter control device 200 starts this process upon acquiring abnormality execution signal D1 output from precharge control unit 104 of vehicle control device 100.

When converter control device 200 starts the step-up drive process for when an abnormality occurs, converter control device 200 executes the process of step S400. In step S400, converter control device 200 starts boosting drive of bidirectional converter 50. Converter control device 200 controls bidirectional converter 50 so that the amount of boosting by bidirectional converter 50 becomes the first boosting amount U1. The first boost amount U1 is the same as the normal boost amount UN. After converter control device 200 executes the process in step S400, it advances the process to step S410.

In step S410, converter control device 200 determines whether converter output voltage VD is greater than change voltage VK. Converter control device 200 stores changed voltage VK in advance. Here, when the lower limit of the output voltage VB that the first battery 22 can take when the first battery 22 is in a normal usable state is the minimum output voltage VN, the changed voltage VK is lower than the minimum output voltage VN. It is set as a rather low value. The minimum output voltage VN of the first battery 22 is the output voltage VB of the first battery 22 when the charging rate of the first battery 22 is the lower limit value of the charging rate that the first battery 22 can take. That is, the minimum output voltage VN of the first battery 22 is determined for each product. Note that the charging rate of the first battery 22 is a value obtained by dividing the remaining capacity of the first battery 22 by the full charge capacity. As mentioned above, since the changed voltage VK is lower than the lowest output voltage VN of the first battery 22, the changed voltage VK is lower than the output voltage VB of the first battery 22 when step S410 is executed. It has a low value.

In the process of step S410, converter control device 200 acquires the latest converter output voltage VD detected by converter voltage sensor 52. Converter control device 200 then compares converter output voltage VD with modified voltage VK. Converter control device 200 executes the process of step S410 again when converter output voltage VD is equal to or lower than change voltage VK (step S410: NO). Converter control device 200 repeats the process of step S410 until converter output voltage VD becomes larger than changed voltage VK. Then, when converter output voltage VD becomes larger than change voltage VK (step S410: YES), converter control device 200 advances the process to step S420.

In step S420, converter control device 200 changes the boost amount by bidirectional converter 50 to second boost amount U2. The second boost amount U2 is determined as a smaller boost amount than the first boost amount U1. Converter control device 200 substantially makes the switching frequency of transistor 50T in bidirectional converter 50 smaller than in the case of the first boost amount. Then, the period during which the transistor 50T is turned off is lengthened.

Converter control device 200 stores second boost amount U2 in advance. The second boost amount U2 is determined by experiments and simulations in consideration of the processing process when stopping the boost drive of the bidirectional converter 50. Specifically, the second boost amount U2 is set to the following value. In the step-up drive process for when an abnormality occurs, the converter control device 200 starts boosting the bidirectional converter 50 after acquiring the abnormality stop signal D2 output by the precharge control unit 104 in the precharge base process for when an abnormality occurs. The drive will be stopped. Regarding the stop of this boost drive, in the precharge base processing, the precharge control unit 104 determines the completion of boosting by the bidirectional converter 50, and then the actual operation is carried out through various processes including sending and receiving the above-mentioned abnormality stop signal D2. The time required for the bidirectional converter 50 to stop switching is defined as the second stop time. The second boost amount U2 is set as a value slightly smaller than the value obtained by dividing the tolerance voltage VP used to calculate the target voltage range VZ by the second stop time. That is, the second boost amount U2 is set such that the amount of increase in the converter output voltage VD during the second stop time is smaller than the tolerance voltage VP.

After converter control device 200 executes the process of step S420 described above, converter control device 200 advances the process to step S430. In step S430, converter control device 200 determines whether or not it has acquired abnormality stop signal D2, which is a signal instructing to stop boosting drive of bidirectional converter 50. This abnormality stop signal D2 is a signal output by the precharge control unit 104 in the precharge base processing for when an abnormality occurs (step S430). If converter control device 200 has not acquired abnormality stop signal D2 (step S430: NO), converter control device 200 executes the process of step S430 again. Converter control device 200 repeats the process of step S430 until it obtains abnormality stop signal D2. When converter control device 200 obtains abnormality stop signal D2 (step S430: YES), the process proceeds to step S440.

In step S440, converter control device 200 stops boosting drive of bidirectional converter 50. Converter control device 200 then ends the series of steps of the step-up drive process for when an abnormality occurs. The above-described series of precharge base processing for when an abnormality occurs and the series of processes related to the boost drive process for when an abnormality occurs constitute the precharge process for when an abnormality occurs.

Next, the operation of this embodiment will be explained.
It is assumed that an acquisition abnormality occurs at time T1 while the vehicle 10 is traveling, and the acquisition abnormality occurrence flag FC is switched from off to on as shown in FIG. 4(c). Thereafter, as shown in FIG. 4A, it is assumed that the ignition switch G is turned off at time T2, and then turned on again at time T3. The positive relay 35 and the negative relay 36 are switched to the cut-off state in response to the ignition switch G being turned off at time T2, and remain in the cut-off state at time T3.

Now, as shown in FIG. 4C, it is assumed that the acquisition abnormality continues even after time T3 when the ignition switch G is turned on. In this case, as shown in FIG. 4(d), the abnormality execution signal D1 is output from the precharge control unit 104 of the vehicle control device 100 via the Zika line 310 (step S320). Then, converter control device 200 starts a boost drive process for when an abnormality occurs (step S400). Here, as shown in FIG. 4(e), the ignition switch G is turned off at time T2, and the converter output voltage VD has decreased to zero by time T3. Then, as described above, when step-up driving of bidirectional converter 50 is started from time T3, converter output voltage VD increases from zero.

As shown in FIG. 4(e), until time T4 when converter output voltage VD reaches change voltage VK, which is slightly lower than the lowest output voltage VN of first battery 22, converter output voltage VD is boosted by the first It is controlled to the boost amount U1 (step S400, step S410). After time T4, the boost amount of converter output voltage VD is controlled to a second boost amount U2 that is smaller than the first boost amount U1 (step S420).

While the bidirectional converter 50 is boosted as described above, the precharge control unit 104 determines when the bidirectional converter 50 has completed boosting based on the target voltage range VZ determined from the output voltage VB of the first battery 22. A determination is made (step S330). Then, at time T5 when this boosting is completed, as shown in FIG. 4(d), an abnormality stop signal D2 is output from the precharge control section 104 via the Zika line 310 (step S340). Then, converter control device 200 stops boosting drive of bidirectional converter 50 (step S440). Then, as shown in FIG. 4(b), the positive relay 35 and the negative relay 36 are brought into a connected state (step S350).

In addition, although FIG. 4 shows the acquisition abnormality occurrence flag FC being turned on and off and the signal output via the Zika line 310 even while the ignition switch G is turned off, this is for convenience only. It is.

Next, the effects of this embodiment will be explained.
(1) In the above configuration, the converter control device 200, which is a control device exclusively for the bidirectional converter 50, executes and stops the step-up drive of the bidirectional converter 50. Under a situation where no acquisition abnormality has occurred, converter control device 200 can acquire target voltage range VZ. Therefore, in the normal precharge process, converter control device 200 itself determines whether the bidirectional converter 50 has completed boosting. Therefore, after the completion of boosting is determined, a signal instructing the bidirectional converter 50 to stop the boosting drive is immediately outputted, so that the boosting drive can be stopped immediately.

On the other hand, under a situation where an acquisition abnormality has occurred, converter control device 200 cannot acquire target voltage range VZ. Therefore, in the precharge processing for when an abnormality occurs, the completion of boosting by the bidirectional converter 50 is determined not by the converter control device 200 but by the precharge control section 104 of the vehicle control device 100. In this case, when stopping the step-up drive of the bidirectional converter 50, the converter control device 200 itself determines whether the step-up is complete, including sending and receiving an abnormality stop signal D2 between the precharge control unit 104 and the converter control device 200. There are more processes than when making a determination and stopping boost drive. Therefore, after it is determined that the boosting is complete, there is a corresponding delay until the bidirectional converter 50 actually stops boosting the voltage.

Boosting by the bidirectional converter 50 continues even during the above delay. From this, if the boost amount of the converter output voltage VD immediately before the converter output voltage VD falls within the target voltage range VZ is a correspondingly large value such as the normal boost amount UN, the converter output voltage will increase during the above delay. There is a possibility that VD exceeds the target voltage range VZ.

Therefore, in the above configuration, after the converter output voltage VD reaches the changed voltage VK, the amount of boost by the bidirectional converter 50 is set to the second boost amount U2, which is smaller than the first boost amount U1. Therefore, immediately before converter output voltage VD falls within target voltage range VZ, the amount of boost by bidirectional converter 50 becomes relatively small. Therefore, during the above-mentioned delay related to stopping the step-up drive of the bidirectional converter 50, it is possible to prevent the converter output voltage VD from exceeding the target voltage range VZ.

(2) Considering the above delay problem related to stopping the boost drive of the bidirectional converter 50, suppose that from the start to the end of the boost drive of the bidirectional converter 50, as shown by the two-dot chain line U2A in FIG. , a second boost amount U2 having a small boost amount is set. In this case, it takes a considerable amount of time for the bidirectional converter 50 to complete boosting.

Therefore, in the above configuration, the boost amount by the bidirectional converter 50 is set to the first boost amount U1, which is the same value as the normal boost amount UN, until the converter output voltage VD reaches the changed voltage VK. In this way, by setting the step-up amount by the bi-directional converter 50 to the first step-up amount U1 until the middle of the execution period of the step-up drive of the bi-directional converter 50, the time required to complete the step-up by the bi-directional converter 50 becomes excessive. can be prevented from becoming too long.

(3) The output voltage VB of the first battery 22 when performing the precharge process increases or decreases depending on the charging rate of the first battery 22 for each precharge process. However, even if there is a rise or fall for each precharge process, the output voltage VB of the first battery 22 when executing the precharge process is the lowest value corresponding to when the charging rate of the first battery 22 is at the lower limit value. It never becomes lower than the output voltage VN. That is, the output voltage VB of the first battery 22, which is the reference value of the target voltage range VZ, is always a value equal to or higher than the minimum output voltage VN. Then, when executing the precharge process, it is determined that boosting is complete and the bidirectional converter 50 is activated after the boost drive of the bidirectional converter 50 is started until the converter output voltage VD reaches the vicinity of the minimum output voltage VN. It is impossible for boost drive to be stopped. Therefore, during the above period, there is no need to reduce the boost amount of the converter output voltage VD in consideration of the problem of the delay related to stopping the boost drive of the bidirectional converter 50. In other words, as long as it is between the above, it is permissible to set a large boost amount regardless of the difference in the output voltage VB of the first battery 22 for each precharge process. Therefore, in the above configuration, the change voltage VK near the lowest output voltage VN is defined as the timing for changing the boost amount, and the first boost amount U1 is set until the converter output voltage VD reaches the change voltage VK. In this way, by defining the change timing using the change voltage VK, it is possible to set a large first boost amount regardless of the difference in the output voltage VB of the first battery 22 for each precharge process.

Note that this embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
- The first boost amount U1 is not limited to the example of the above embodiment. That is, the first boost amount U1 may be different from the normal boost amount UN. The larger the first boost amount U1, the shorter the time required for the bidirectional converter 50 to complete boosting.

- The second boost amount U2 is not limited to the example of the above embodiment. The second boost amount U2 only needs to be smaller than the first boost amount U1. Further, the second boost amount U2 is such that when the boosting by the bidirectional converter 50 actually stops, the converter output voltage VD exceeds the limit difference voltage VPM from the output voltage VB of the first battery 22 during the precharging process. It suffices if it is set to be less than or equal to the added value.

- The changing voltage VK is not limited to the example of the above embodiment. The changed voltage VK may have a value smaller than the output voltage VB of the first battery 22 when performing the precharge process. If the changed voltage VK has a value smaller than the output voltage VB of the first battery 22, the converter output voltage VD will exceed the target voltage range VZ during the above-mentioned delay related to stopping the step-up drive of the bidirectional converter 50. This can be prevented.

When changing the changed voltage VK from the above embodiment, the changed voltage VK may be calculated by the precharge control unit 104 for each precharge process. Specifically, during execution of the precharge process, the precharge control unit 104 calculates the changed voltage VK based on the output voltage VB of the first battery 22 as a value slightly lower than the output voltage VB. Then, when the charging voltage VC1 of the first capacitor 41 increases as the bidirectional converter 50 is boosted and the charging voltage VC1 reaches the changed voltage VK, the precharge control unit 104 disconnects the Zika line 310. A change signal instructing a change in the boost amount is output to converter control device 200 via the converter controller 200 . In response to this change signal, converter control device 200 changes the boost amount by bidirectional converter 50 from the first boost amount U1 to the second boost amount U2. In order to realize such an aspect, a change signal may be outputted from the Zika line 310 as a signal different from the abnormality execution signal D1 and the abnormality stop signal D2 of the above-described embodiment. Furthermore, the contents of the precharge base processing and boost drive processing for when an abnormality occurs may be changed so as to realize the above aspect.

- The method of calculating the target voltage range VZ is not limited to the example of the above embodiment. For example, the lower limit value of the target voltage range VZ may be calculated as a value obtained by subtracting the tolerance voltage VP from the output voltage VB of the first battery 22. Then, the upper limit value of the target voltage range VZ may be calculated as the output voltage VB of the first battery 22.

- Calculate the lower limit value of the target voltage range VZ as the value obtained by subtracting the tolerance voltage VP from the output voltage VB of the first battery 22, and set the upper limit value of the target voltage range VZ to the output voltage VB of the first battery 22. It may be calculated as a value obtained by adding the difference voltage VP. In this case, the tolerance voltage VP used to calculate the lower limit value of the target voltage range VZ and the tolerance voltage VP used to calculate the upper limit value may be different values. The tolerance voltage VP may have a value equal to or less than the limit difference voltage VPM.

- The tolerance voltage VP may be set to zero. In this case, the target voltage range VZ does not have a constant width but has a specific value. Even in this case, due to the setting of the second step-up amount U2, when the step-up by the bidirectional converter 50 actually stops, the converter output voltage VD has a limit difference from the output voltage VB of the first battery 22 during the precharge process. The value becomes less than the sum of the voltage VPM.

- The determination parameters for determining the presence or absence of acquisition abnormality are not limited to the examples in the above embodiment. The determination parameter may be any parameter that can determine the transmission and reception of signals between converter control device 200 and vehicle control device 100 via CAN communication line 300.

- The configuration of the power supply circuit 16 is not limited to the example of the above embodiment. For example, a temperature sensor may be added to monitor the state of the first battery 22.
- The configuration of the load 18 is not limited to the example of the above embodiment. For example, the load may be composed of only the motor generator 14 and the inverter 90.

- The number of motor generators 14 may be changed as appropriate.
- The vehicle 10 may be configured as an electric vehicle without the internal combustion engine 12.

DESCRIPTION OF SYMBOLS 11... Power supply control device 16... Power supply circuit 18... Load 22... First battery 29... Second battery 35... Positive pole relay 36... Negative pole relay 50... Bidirectional converter 100... Vehicle control device 104... Precharge control unit 200... Converter control Device (converter control unit)

Claims (1)

a first battery;
a relay that connects and disconnects electrical connection from the first battery to a load;
a second battery having a lower rated voltage than the first battery;
applied to a power supply circuit comprising: a converter that boosts the output voltage of the second battery and outputs it to the load side beyond the relay;
With the electrical connection between the first battery and the load cut off by the relay, the output voltage of the converter reaches a value within a target voltage range determined based on the output voltage of the first battery. A control device that executes precharge processing to boost drive a converter,
a precharge management unit that calculates the target voltage range;
a converter control unit that acquires the target voltage range from the precharge control unit and boosts the converter toward the target voltage range;
When performing the precharge process in a situation where an acquisition abnormality occurs in which the converter control unit cannot acquire the target voltage range,
When the converter is boosted, the converter control section is configured to: until the output voltage of the converter reaches a changed voltage, which is determined as a voltage lower than the output voltage of the first battery, than after reaching the changed voltage, when boosting the converter; increasing the amount of boost per unit time by the converter,
The precharge control unit outputs a stop signal for stopping boost drive of the converter to the converter control unit when the output voltage of the converter reaches a value within the target voltage range.