Vehicle control system

Abstract

This reduces the risk of overheating caused by the battery not being cooled during external charging. [Solution] The control ECU controls the vehicle. The vehicle is equipped with a battery that can be externally charged and stores power to drive the vehicle, and a compressor that compresses a refrigerant to lower the temperature of the passenger compartment using the rotational force generated by the battery's power. The battery is cooled by the cold of the refrigerant. When the decrease in the rotational speed of the compressor during external charging of the battery meets predetermined conditions, the control ECU controls the compressor to maintain a rotational speed at which the battery is not supplied with charging power exceeding the charging power limit value Win (S114, S116, S117). As a result, even if the rotational speed of the compressor decreases during external charging, the compressor is controlled to maintain a rotational speed at which the battery is not supplied with charging power exceeding the charging power limit value Win. Therefore, it is possible to prevent the battery from being supplied with charging power exceeding the charging power limit value Win.

Description

Technical Field

[0001] This disclosure relates to a control device for a vehicle, particularly to a control device for a vehicle including a power storage device capable of external charging and storing power for driving the vehicle, and a compressor that compresses a refrigerant for reducing the temperature of a vehicle compartment by a rotational force generated by the power of the power storage device.

Background Art

[0002] Conventionally, there has been a control technique for operating a compressor of an air conditioner to cool a power storage device during external charging (see, for example, Patent Document 1 and Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In some vehicles, when the ignition switch is turned from on to off, the compressor that was operating during external charging stops. This causes a sharp drop in the compressor's rotational speed, which worsens the cooling capacity of the energy storage device. As a result, the temperature of the energy storage device may rise. Furthermore, if the power supply requirement for the charging equipment is set to the energy storage device's charging power limit value Win plus the power consumption of the compressor used to cool the energy storage device during charging, the following problem occurs: When the compressor's rotational speed drops sharply, the compressor's power consumption also drops sharply. This results in power exceeding the charging power limit value Win being supplied to the energy storage device. As a result, problems such as lithium deposition on the electrodes of the energy storage device may occur. To avoid this problem, if the power supply requirement for the charging equipment is set to the energy storage device's charging power limit value Win, the power consumption of the compressor will reduce the charging power. As a result, the charging time will increase.

[0005] This disclosure is made to solve the aforementioned problems, and its purpose is to provide a vehicle control device that can suppress the risk of overheating due to the storage device not being cooled during external charging. [Means for solving the problem]

[0006] The control device described in this disclosure controls a vehicle. The vehicle includes a power storage device that can be externally charged and stores power to drive the vehicle, and a compressor that compresses a refrigerant to lower the temperature of the vehicle's interior using the rotational force generated by the power of the power storage device. The power storage device is cooled by the cold energy of the refrigerant. When the decrease in the rotational speed of the compressor during external charging of the power storage device satisfies predetermined conditions, the control device controls the compressor to maintain a rotational speed at which the power supply to the power storage device does not exceed a charging power limit.

[0007] With this configuration, even if the compressor's rotational speed decreases during external charging of the energy storage device, the compressor is controlled to maintain a rotational speed that does not supply charging power exceeding the charging power limit to the energy storage device. Therefore, it is possible to prevent the supply of charging power exceeding the charging power limit to the energy storage device. As a result, it is possible to provide a vehicle control device that can suppress the risk of overheating due to the energy storage device not being cooled during external charging.

[0008] The control device may set the power obtained by adding the compressor's power consumption to the charging power limit as the power required for external charging.

[0009] With this configuration, the energy storage device is continuously supplied with charging power up to the charging power limit. As a result, it is possible to prevent the application of charging power exceeding the charging power limit to the energy storage device. In addition, it is possible to suppress an increase in the charging time of the energy storage device.

[0010] The control device may maintain the rotational speed and control the external charging power to be consumed by a specific device that consumes power in place of or together with the compressor, if the rotational speed decreases during external charging of the energy storage device and meets predetermined conditions.

[0011] With this configuration, even if the compressor's rotational speed decreases during external charging of the energy storage device, a specific device can consume power exceeding the charging power limit for the energy storage device. As a result, it is possible to suppress the supply of charging power exceeding the charging power limit.

[0012] The specific device may be an inverter for the motor that drives the vehicle. With such a configuration, even if the rotational speed of the compressor decreases during external charging of the energy storage device, the inverter can consume power exceeding the charging power limit for the energy storage device. As a result, it is possible to suppress the supply of charging power exceeding the charging power limit. [Effects of the Invention]

[0013] This disclosure provides a vehicle control device that can suppress the risk of overheating due to the storage device not being cooled during external charging. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram of the vehicle according to this embodiment. [Figure 2] This is a diagram illustrating an example of a cooling device. [Figure 3] This flowchart shows the flow of the charging power control process in this embodiment. [Modes for carrying out the invention]

[0015] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated.

[0016] Figure 1 is a schematic diagram of the vehicle 1 according to this embodiment. In this embodiment, vehicle 1 is an electric vehicle, for example, an electric vehicle (BEV: Battery Electric Vehicle). Vehicle 1 comprises a motor generator (MG: Motor Generator) 10, a power transmission gear 20, drive wheels 30, a power control unit (PCU: Power Control Unit) 40, a system main relay (SMR: System Main Relay) 50, a battery 100, a monitoring unit 200, a battery ECU (Electronic Control Unit) 250, and a control ECU 300.

[0017] The MG10 has both the function of an electric motor and a generator. The output torque of the MG10 is transmitted to the drive wheels 30 via a power transmission gear 20 which includes a reduction gear and a differential.

[0018] When the vehicle 1 is braking, the MG10 is driven by the drive wheels 30, and the MG10 operates as a generator. The regenerative power generated by the regenerative braking force in the MG10 is stored in the battery 100.

[0019] The PCU40 is a power conversion device that converts power bidirectionally between the MG10 and the battery 100. The PCU40 includes, for example, an inverter and a converter that operate based on a control signal from the control ECU300, and drives the MG10.

[0020] The SMR50 is electrically connected to the power line connecting the battery 100 and the PCU40. When the SMR50 is turned ON in response to a control signal from the control ECU300 and is in a conductive state, power can be exchanged between the battery 100 and the PCU40. On the other hand, when the SMR50 is turned OFF and is in a cut-off state, the electrical connection between the battery 100 and the PCU40 is cut off.

[0021] The battery 100 stores power for driving the MG10. The battery 100 is a secondary battery and is a battery pack composed of a plurality of single batteries (battery cells) 110. The single battery is composed of, for example, a lithium-ion battery, may be a nickel-metal hydride battery, or may be a all-solid-state battery.

[0022] The monitoring unit 200 includes a voltage detection unit, a current sensor, and a temperature detection unit. The voltage detection unit detects the battery voltage VB. The current sensor detects the current IB input to and output from the battery 100. The temperature detection unit detects the temperature TB of the battery 100. The voltage VB, the temperature TB, and the current IB are input to the battery ECU250. The battery ECU250 calculates the SOC (State Of Charge) of the battery 100. The SOC may be calculated, for example, by the Coulomb count method, the SOC-OCV (Open Circuit Voltage) characteristic, or a combination of these. The voltage VB, the temperature TB, the current IB, and the SOC are output from the battery ECU250 to the control ECU300.

[0023] Vehicle 1 is equipped with a DC inlet 60 and an AC inlet 80, and the battery 100 can be charged (externally charged) from an external DC power supply 400 or an external AC power supply 500, or other charging equipment (EVSE: Electric Vehicle Supply Equipment) 2. When the connector 420 at the end of the charging cable 410 of the external DC power supply (EVSE) 400 is connected to the DC inlet 60, the charging relay 70 is controlled to the connected state, and external charging (rapid charging) of the battery 100 is performed.

[0024] When the connector 520 at the end of the charging cable 510 of the external AC power supply (EVSE) 500 is connected to the AC inlet 80, the onboard charger 130 converts the alternating current power supplied from the external AC power supply into direct current power. The direct current power output from the onboard charger 130 is supplied to the battery 100 via the charging relay 90, and external charging (normal charging) of the battery 100 is performed.

[0025] The control ECU 300 includes a CPU (Central Processing Unit) 301 and a memory 302. Based on signals received from the battery ECU 250, signals from various sensors (not shown) (e.g., accelerator opening signal, vehicle speed signal, etc.), and information such as maps and programs stored in the memory 302, the control ECU 300 controls each device so that the vehicle 1 reaches a desired state. The control ECU 300 controls the cooling system 800. The battery ECU 250 also includes a CPU and memory, similar to the control ECU 300.

[0026] The power switch (ignition switch) 350 is operated by the user. For example, if the user operates the power switch 350 while pressing the brake pedal (not shown), the control ECU 300 controls the SMR50 to turn ON (conductive state). When the SMR50 is ON, the PCU 40 enables the MG10 to be driven (the drive system is started), and vehicle 1 becomes drivable. If the user operates the power switch 350 while vehicle 1 is drivable, the SMR50 turns OFF (disconnected state), the PCU 40 etc (drive system) stops, and vehicle 1 comes to a stop.

[0027] The Human-Machine Interface (HMI) device 700 includes an input device and a display device. The input device and display device may be a touch panel display.

[0028] Vehicle 1 is equipped with a cooling system 800. The cooling system 800 cools the battery 100. Figure 2 is a diagram illustrating an example of the cooling system 800. In this embodiment, the cooling system 800 consists of a thermal management circuit capable of cooling and heating the battery 100. The cooling system 800 (thermal management circuit) includes a thermal circuit S and a refrigeration cycle R.

[0029] The refrigeration cycle R circulates a refrigerant. The refrigeration cycle R includes a compressor R1 and a condenser R2. Compressor R1 compresses the refrigerant using a motor with a controllable rotational speed, which operates on power from battery 100 according to a control signal from control ECU 300. The power consumption of compressor R1 is approximately proportional to the flow rate of refrigerant discharged from compressor R1, i.e., the rotational speed of the motor driving compressor R1. The refrigerant compressed by compressor R1 flows into condenser R2. The high-pressure refrigerant discharged from condenser R2 flows into evaporator R3 via an electric expansion valve, and also flows into chiller Ch via an electric expansion valve. Evaporator R3 is used as the cooling source for the air conditioning system of vehicle 1. Chiller Ch exchanges heat with a heat transfer medium circulating in a heat circuit S, thereby cooling the heat transfer medium.

[0030] The thermal circuit S circulates a heat transfer medium. The thermal circuit S includes a three-way valve S1, a battery 100, a reserve tank (R / T), an SPU (Smart Power Unit), a PCU 40, an oil cooler (O / C), and pumps W1 and W2. The oil cooler cools the oil that cools the transaxle (T / A) with the heat transfer medium of the thermal circuit S. The EOP circulates the oil that cools the transaxle. When pump W1 is activated, ports P1 and P2 of the three-way valve S1 are connected, and the heat transfer medium cooled by the chiller Ch circulates through the battery 100, thereby cooling the battery 100. When pump W2 is activated, ports P2 and P3 of the three-way valve S1 are connected, and the heat transfer medium heated by the waste heat from the SPU, PCU 40, and O / C circulates through the battery 100, thereby heating the battery 100. An electric heater may be installed between port P2 and battery 100.

[0031] The heat transfer medium circulating in the heat circuit S may be, for example, insulating oil or insulating antifreeze. The refrigeration cycle R and the heat circuit S (compressor R1, pumps W1, W2, etc.) are driven by power stored in the battery 100.

[0032] In this vehicle 1, when the power switch 350 is turned from on to off, the air conditioner control is reset, causing the compressor R1, which was operating during external charging, to stop. As a result, the rotational speed of the compressor R1 drops sharply, worsening the cooling capacity of the battery 100. This may cause the temperature of the battery 100 to rise. Furthermore, if the power supply requirement for the charging equipment, such as the external DC power supply 400 or external AC power supply 500, is set to the battery 100's charging power limit value Win plus the power consumption of the compressor R1 used to cool the battery 100 during charging, the following problem occurs: When the rotational speed of the compressor R1 drops sharply, the power consumption of the compressor R1 also drops sharply. This results in power exceeding the charging power limit value Win being supplied to the battery 100. Consequently, problems such as lithium deposition on the electrodes of the battery 100's individual cells 110 occur. To avoid this problem, if the power supply requirement for the charging equipment is set to the charging power limit value Win for battery 100, the power consumption of compressor R1 will reduce the charging power. As a result, the charging time will increase.

[0033] Therefore, if the rotational speed of the compressor R1 decreases during external charging of the battery 100, the control ECU 300 controls the compressor R1 to maintain a rotational speed at which charging power exceeding the charging power limit value Win is not supplied to the battery 100.

[0034] As a result, even if the rotational speed of the compressor R1 decreases during external charging of the battery 100, the compressor R1 is controlled to maintain a rotational speed that does not supply charging power exceeding the charging power limit value Win to the battery 100. Therefore, it is possible to prevent the supply of charging power exceeding the charging power limit value Win to the battery 100. Consequently, the risk of overheating due to the battery 100 not being cooled during external charging can be suppressed.

[0035] Figure 3 is a flowchart showing the flow of the charging power control process in this embodiment. Referring to Figure 3, this charging power control process is called and executed by the control ECU 300 at predetermined intervals from a higher-level process.

[0036] The CPU 301 of the control ECU 300 determines whether or not the vehicle's battery 100 is being externally charged from the external DC power supply 400 (step S111). If it determines that DC charging is in progress (YES in step S111), the CPU 301 determines whether or not the compressor R1 is operating to cool the battery 100 (step S112). If it determines that DC charging is not in progress (NO in step S111), the CPU 301 returns the processing to be executed to the higher-level processing that called this charging power control processing.

[0037] If the CPU 301 determines that the compressor R1 is not operating (NO in step S112), it limits the power supplied to the external DC power supply 400 to the battery 100's charging power limit value Win (step S113). As a result, the charging power of the battery 100 is limited to the charging power limit value Win. After step S113, the CPU 301 returns the processing to the higher-level processing that called this charging power control process.

[0038] If the CPU 301 determines that the compressor R1 is operating to cool the battery (YES in step S112), it determines whether the decrease in the number of rotations per unit time (rotational speed) of the compressor R1 exceeds a predetermined threshold (step S114). The predetermined threshold is a value set so that the charging power of the battery 100 does not exceed the charging power limit value Win. If the CPU 301 determines that the decrease in rotational speed does not exceed the predetermined threshold (NO in step S114), it adds the power consumed by the compressor R1 to the power supply requested from the external DC power supply 400 (step S115). This allows power to be supplied to the compressor R1 from the external DC power supply 400 while keeping the charging power of the battery 100 at the charging power limit value Win. After step S115, the CPU 301 returns the processing to be executed to the higher-level processing that called this charging power control processing.

[0039] On the other hand, if the CPU 301 determines that the decrease in rotational speed exceeds a predetermined threshold (YES in step S114), it adds the power consumed by the compressor R1 to the power supplied to the external DC power supply 400 (step S116), and maintains the rotational speed of the compressor R1 per unit time at a level where power exceeding the charging power limit value Win is supplied to the battery 100 (step S117). In other words, it maintains the power supplied from the external DC power supply 400, excluding the power supplied to the battery 100 that exceeds the charging power limit value Win, at a rotational speed per unit time that the compressor R1 can consume. After step S117, the CPU 301 returns the processing to be executed to the higher-level processing that called this charging power control processing.

[0040] [Differentiation] (1) In the embodiment described above, as shown in step S117 of Figure 3, the power supplied from the external DC power supply 400, excluding the power of the charging power limit value Win supplied to the battery 100, is consumed by the compressor R1. However, the invention is not limited to this, and the power supplied from the external DC power supply 400, excluding the power of the charging power limit value Win supplied to the battery 100, may be consumed by the compressor R1 and also by the conduction loss of the inverter and the copper loss of the MG10 by switching control of the inverter of the PCU 40, or it may be consumed by the inverter of the PCU 40 instead of the compressor R1.

[0041] (2) In the embodiment described above, as shown in step S111 in Figure 3, the process from step S112 onwards is executed when DC charging is in progress. However, the invention is not limited to this, and the process from step S112 onwards may be executed when AC charging is in progress.

[0042] (3) In the embodiment described above, as shown in Figure 2, the battery 100 is cooled by the heat transfer medium of the heat circuit S, which is cooled by the refrigerant of the refrigeration cycle R compressed by the compressor R1, and the battery 100 is cooled by the heat transfer medium. However, it is not limited to this, and the battery 100 may be cooled by other methods as long as it is cooled by the refrigerant compressed by the compressor R1. For example, instead of being cooled indirectly by the refrigerant as shown in Figure 2, it may be cooled directly by the refrigerant.

[0043] (4) In the embodiment described above, in step S114 of Figure 3, steps S116 and S117 are executed if the decrease in the rotational speed of the compressor R1 per unit time exceeds a predetermined threshold. However, the invention is not limited to this, and steps S116 and S117 may be executed if the decrease in the rotational speed of the compressor R1 during external charging of the battery satisfies a predetermined condition. The predetermined condition is not limited to the condition that the decrease in the rotational speed of the compressor R1 per unit time exceeds a predetermined threshold, but may also be the condition that the rotational speed of the compressor R1, the rotational speed of the battery 100, or the charging power of the battery 100 is less than a predetermined rotational speed determined so as not to exceed the charging power limit value Win.

[0044] (5) In the embodiment described above, as shown in Figure 3, the charging power of the battery 100 is limited to the charging power limit value Win, and the process in Figure 3 is executed using the charging power limit value Win. However, the invention is not limited to this, and the process in Figure 3 may be executed using other values ​​instead of the charging power limit value Win. For example, the process in Figure 3 may be executed using a predetermined percentage (for example, 90%) of the charging power limit value Win, or the process in Figure 3 may be executed using a value obtained by subtracting a predetermined value from the charging power limit value Win.

[0045] (6) The embodiments described above can be interpreted as disclosures of a vehicle 1 or a control device such as the control ECU 300 of vehicle 1 shown in Figure 1, or as disclosures of a control method or control program such as the one shown in Figure 3 that is executed by vehicle 1 or the control device of vehicle 1.

[0046] [summary] (1) As shown in Figures 1 and 2, the control ECU 300 controls the vehicle 1. As shown in Figures 1 and 2, the vehicle 1 includes a battery 100, which is an energy storage device that can be externally charged and stores power to drive the vehicle 1, and a compressor R1 that compresses a refrigerant to lower the temperature of the passenger compartment using the rotational force generated by the battery 100. As shown in Figure 2, the battery 100 is cooled by the cold of the refrigerant. As shown in Figure 3, if the decrease in the rotational speed of the compressor R1 during external charging of the battery 100 satisfies predetermined conditions, the control ECU 300 controls the compressor R1 to maintain a rotational speed at which charging power exceeding the charging power limit value Win is not supplied to the battery 100 (for example, steps S114, S116, and S117).

[0047] As a result, even if the rotational speed of the compressor R1 decreases during external charging of the battery 100, the compressor R1 is controlled to maintain a rotational speed that does not supply charging power exceeding the charging power limit value Win to the battery 100. Therefore, it is possible to prevent the supply of charging power exceeding the charging power limit value Win to the battery 100. Consequently, the risk of overheating due to the battery 100 not being cooled during external charging can be suppressed.

[0048] (2) As shown in Figure 3, the control ECU 300 may use the power obtained by adding the power consumption of the compressor R1 to the charging power limit value Win as the power to be requested for external charging (for example, in steps S115 and S116).

[0049] This ensures that battery 100 is continuously supplied with charging power up to the charging power limit value Win. As a result, it is possible to prevent the application of charging power exceeding the charging power limit value Win to battery 100. Furthermore, since the maximum charging power is continuously supplied to battery 100, the increase in the charging time of battery 100 can be suppressed.

[0050] (3) As shown in the modified example, the control ECU 300 may maintain the rotational speed and control the external charging power to be consumed by a specific device (e.g., the inverter of the PCU 40, MG10) that consumes power in place of or together with the compressor R1 if the rotational speed decreases during external charging of the battery 100 under predetermined conditions.

[0051] This allows a specific device to consume power exceeding the charging power limit Win for battery 100, even if the rotation speed of the compressor R1 decreases during external charging of battery 100. As a result, it is possible to suppress the supply of charging power exceeding the charging power limit Win.

[0052] (4) As shown in the modified example, the specific device may be the inverter of the PCU40 of the MG10 that drives the vehicle 1.

[0053] This allows the inverter of the PCU40 to consume power exceeding the charging power limit Win for battery 100, even if the rotation speed of the compressor R1 decreases during external charging of battery 100. As a result, it is possible to suppress the supply of charging power exceeding the charging power limit Win.

[0054] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0055] 1 Vehicle, 10 MG, 20 Power transmission gear, 30 Drive wheels, 40 PCU, 50 SMR, 60 DC inlet, 70, 90 Charging relay, 80 AC inlet, 100 Battery, 110 Single cell, 130 Onboard charger, 200 Monitoring unit, 250 Battery ECU, 300 Control ECU, 301 CPU, 302 Memory, 350 Power switch, 400 External DC power supply, 410, 510 Charging cable, 420, 520 Connector, 500 External AC power supply, 700 HMI device, 800 Cooling device, Ch Chiller, P1, P2, P3 Port, R Refrigeration cycle, R1 Compressor, R2 Condenser, R3 Evaporator, S Thermal circuit, S1 Three-way valve, W1, W2 Pump.

Claims

1. A vehicle control device, The aforementioned vehicle is A power storage device that can be charged externally and stores power to drive the vehicle, The system includes a compressor that compresses a refrigerant to lower the temperature of the vehicle interior using the rotational force generated by the power of the aforementioned energy storage device, The energy storage device is cooled by the cold energy of the refrigerant, The control device is A vehicle control device that, when the rotational speed of the compressor decreases during external charging of the energy storage device, satisfies predetermined conditions, controls the compressor to maintain a rotational speed such that no charging power exceeding a charging power limit is supplied to the energy storage device.

2. The control device for a vehicle according to claim 1, wherein the control device uses the power obtained by adding the power consumption of the compressor to the charging power limit as the power to be requested for external charging.

3. The control device for a vehicle according to claim 1 or 2, wherein, when the decrease in rotational speed during external charging of the energy storage device satisfies the predetermined conditions, the control device maintains the rotational speed and controls the power for external charging to be consumed by a specific device that consumes power in place of or together with the compressor.

4. The vehicle control device according to claim 3, wherein the specified device is an inverter for a motor that drives the vehicle.

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