Control device for electric vehicle

Abstract

To suppress shortage of SOC of a battery during travel of an electric vehicle including a battery which is charged with power supplied from the outside according to a predetermined charge / discharge plan.SOLUTION: Disclosed is a control device for an electric vehicle including a battery which is charged with power supplied from the outside according to a predetermined charge / discharge plan, and an auxiliary machine which is operated by consuming power stored in the battery. When charging power supplied to the battery according to the charge / discharge plan is equal to or less than consumption power which is consumed by the auxiliary machine, the control device for the electric vehicle cancels the charge / discharge plan so as to charge the battery with power larger than the consumption power.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a control device for an electric vehicle including a battery that is charged by externally supplied power. [Background technology]

[0002] Conventionally, electric vehicle management systems that control charging and discharging between an electric vehicle's battery and an external charging / discharging device are known (see, for example, Patent Document 1). This electric vehicle management system includes an energy management system that formulates a charging / discharging plan for the battery and controls charging and discharging of the battery based on the charging / discharging plan, and a mobile terminal capable of communicating with the energy management system via a public wireless line. The mobile terminal also includes a constraint / target value creation unit that creates control constraints and control target values ​​for power control of the electric vehicle based on the charging / discharging plan formulated by the energy management system and settings input via a user interface; an optimal control plan creation unit that formulates an optimal control plan for power control of power consumption elements of the electric vehicle so as to obtain the control target values ​​while satisfying the control constraints; and an electric vehicle control unit that issues control instructions to the power consumption elements of the electric vehicle based on the optimal control plan. Furthermore, the optimal control plan creation unit of the mobile terminal formulates an optimal control plan that takes into account the energy consumption of accessories such as an air conditioner while the electric vehicle is traveling, based on weather and temperature information. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-22094 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even if an optimal control plan is formulated taking into consideration the energy consumption of the auxiliary devices while the electric vehicle is running, depending on the state of the electric vehicle while the battery is being charged with power from an external charging / discharging device, the battery's SOC may become insufficient while the electric vehicle is running, making it impossible to run the electric vehicle according to the optimal control plan.

[0005] Therefore, the main object of the present disclosure is to prevent a shortage of the SOC of a battery in an electric vehicle including a battery that is charged with power supplied from an external source according to a predetermined charge / discharge plan while the electric vehicle is traveling. [Means for solving the problem]

[0006] The control device for an electric vehicle disclosed herein is a control device for an electric vehicle that includes a battery that is charged with power supplied from an external source in accordance with a predetermined charge / discharge plan, and an auxiliary device that operates by consuming the power stored in the battery, and when the charging power supplied to the battery in accordance with the charge / discharge plan is less than or equal to the power consumption consumed by the auxiliary device, the charge / discharge plan is canceled, and the battery is charged with power greater than the power consumption.

[0007] The control device for an electric vehicle disclosed herein cancels a predetermined charge / discharge plan when the charging power supplied to the battery according to the plan is equal to or less than the power consumed by the accessories. The charge / discharge plan is then canceled, and the battery is charged with power greater than the power consumed by the accessories. This allows the battery's SOC to be kept sufficiently high by the external power even if the accessories of the electric vehicle consume power from the battery when the battery is being charged with external power. This effectively prevents the battery's SOC from becoming insufficient while the electric vehicle is traveling. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram showing an electric vehicle including a control device according to the present disclosure. [Figure 2]FIG. 2 is an explanatory diagram illustrating an example of a charge / discharge plan. [Figure 3] 3 is a flowchart showing a routine executed by the control device of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Next, embodiments of the present disclosure will be described with reference to the drawings.

[0010] FIG. 1 is a schematic diagram showing an electric vehicle 20 including a control device according to the present disclosure. The electric vehicle 20 shown in the figure is a battery electric vehicle (BEV) and includes a battery (high-voltage battery) 21, a system main relay SMR, a power control device (hereinafter referred to as "PCU") 22, and a motor generator MG. However, the electric vehicle 20 may also be a plug-in hybrid vehicle (PHEV). The battery 21 is, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery. A positive power line PL is connected to a positive terminal of the battery 21 via a positive relay of the system main relay SMR. A negative power line NL is connected to a negative terminal of the battery 21 via a negative relay of the system main relay SMR.

[0011] The PCU 22 is connected to the battery 21 via a positive power line PL, a negative power line NL, and a system main relay SMR. The PCU 22 includes an inverter (drive circuit) 22i that drives the motor generator MG, a boost converter 22c, and the like. The motor generator MG is a synchronous generator motor (three-phase AC motor). The rotor of the motor generator MG is connected to a drive shaft DS that is connected to the drive wheels DW via a power transmission mechanism that includes a reducer and a differential gear. The motor generator MG is driven by electric power from the PCU 22 (battery 21) and outputs drive torque (drive force) to the drive shaft DS. Furthermore, the motor generator MG outputs regenerative braking torque to the drive shaft DS when braking the electric vehicle 20.

[0012] Electric vehicle 20 also includes a bidirectional DC / DC converter (DDC) 23, high-voltage auxiliary equipment 24, and an on-board charger / discharger 25. Bidirectional DC / DC converter 23 is connected to a positive-side power line PL and a negative-side power line NL between system main relay SMR and PCU 22, and is also connected to an auxiliary battery (low-voltage battery) and multiple low-voltage auxiliary equipment (not shown) via a low-voltage power line. Bidirectional DC / DC converter 23 can step down the power on the battery 21 and PCU 22 side and supply it to the low-voltage power line side, i.e., the auxiliary battery and various auxiliary equipment, and can also step up the power from the auxiliary battery and supply it to battery 21 and PCU 22 side. The auxiliary battery is, for example, a lead-acid battery with a rated output voltage of approximately 12 V, and the multiple low-voltage auxiliary equipment includes lights, audio equipment, etc.

[0013] High-voltage auxiliaries 24 are also connected to the positive power line PL and the negative power line NL between the system main relay SMR and PCU 22. High-voltage auxiliaries 24 include a compressor (inverter compressor) of an air conditioner that conditions the air inside the passenger compartment of electric vehicle 20, a converter to AC 100V, and a temperature control device (heater and cooler) for battery 21. On-board charger / discharger 25 includes an AC / DC converter and a DC / DC converter, and is connected to a charge / discharge inlet 26 (receptacle) provided on the body of electric vehicle 20, and is also connected to the positive power line PL and the negative power line NL between the system main relay SMR and PCU 22 via a charge relay CHR.

[0014] The charge / discharge inlet 26 can be connected to a charging connector of a charging station outside the vehicle, a charging connector of a charging cable (EVSE) connected to a household power source (outlet), an external power supply connector (VPC), etc. The charge / discharge inlet 26 is connected to the battery 21 via the on-board charger / discharger 25 or the like when the charging relay CHR and the system main relay SMR are closed. This makes it possible to convert AC power supplied from outside the vehicle to the charge / discharge inlet 26 into DC power by the on-board charger / discharger 25 and charge the battery 21 with the DC power. Furthermore, in this embodiment, by connecting a predetermined connector (cable), power equipment, etc. to the charge / discharge inlet 26, the battery 21 of the electric vehicle 20 can be connected to the power system PS of a virtual power plant (VPP). This makes it possible to charge the battery 21 with power supplied from the power system PS to the charge / discharge inlet 26 and to supply power stored in the battery 21 to the power system PS (reverse power flow). The power system PS supplies AC power and may include a power generation system that generates power from renewable energy sources such as wind power and solar power.

[0015] Furthermore, the electric vehicle 20 includes a master electronic control unit (hereinafter referred to as "BEVECU") 200 that performs overall control of the entire vehicle, a charge / discharge electronic control unit (hereinafter referred to as "charge / discharge ECU") 201 as a control device of the present disclosure that executes control related to charging and discharging of the battery 21, and an on-board communication device (gateway ECU) 202. The BEVECU 200 includes a microcomputer having a CPU, ROM, RAM, input / output devices, etc. (not shown), and controls the PCU 22, i.e., the motor / generator MG, in cooperation with other ECUs (not shown). The BEVECU 200 also controls the opening and closing of the system main relay SMR. Furthermore, when the electric vehicle 20 is in system startup, the BEVECU 200 calculates the total power consumption Ec of the auxiliaries at predetermined time intervals (very short time intervals), which is the sum of the DC power output from the bidirectional DC / DC converter 23 to the auxiliaries side, i.e., the low-voltage power line, and the power consumption (DC power) by the high-voltage auxiliaries 24.

[0016] The charge / discharge ECU 201 includes a microcomputer having a CPU, ROM, RAM, input / output devices, etc. (not shown), and controls the on-board charger / discharger 25 and controls the opening and closing of the charge relay CHR. The charge / discharge ECU 201 also calculates the SOC of the battery 21, the allowable charging power Win for charging the battery 21, and the allowable discharging power Wout for discharging the battery 21, based on the terminal voltage, charging / discharging current, temperature, etc. of the battery 21. The on-board communication device 202 exchanges various information with the BEVECU 200 and the charge / discharge ECU 201. The on-board communication device 202 also exchanges various information with an external device such as the virtual power plant management server 300 via high-speed wireless data communication (packet communication). The on-board communication device 202 also acquires GPS time and exchanges various information with a mobile terminal 30, such as a smartphone, owned by the owner of the electric vehicle 20 via high-speed wireless data communication (packet communication).

[0017] The management server 300 of the virtual power plant includes a computer having a CPU, ROM, RAM, input / output devices, etc., and a storage device for storing various information. The management server 300 creates a power usage plan for the virtual power plant and a charge / discharge plan for the battery 21 of the electric vehicle 20, which serves as the energy resource of the virtual power plant. FIG. 2 shows an example of a charge / discharge plan for the battery 21 created by the management server 300. As shown in FIG. 2, the charge / discharge plan for the battery 21 specifies, for each time period (GPS time), the charging power (DC power) Pc for charging the battery 21 or the discharging power to be discharged from the battery 21 (only the charging power Pc is shown in the example of FIG. 2). Every time the management server 300 creates a charge / discharge plan, it transmits the created charge / discharge plan to the on-board communication device 202 of the corresponding electric vehicle 20.

[0018] Next, a procedure for charging the battery 21 of the electric vehicle 20 with power from the power system PS of the virtual power plant will be described with reference to Fig. 3. Fig. 3 is a flowchart showing a routine executed by the charge / discharge ECU 201 when a predetermined connector is connected to the charge / discharge inlet 26 of the electric vehicle 20 and the battery 21 is connected to the virtual power plant.

[0019] 3, the charge / discharge ECU 201 acquires the charge / discharge plan transmitted from the management server 300 (step S100), and determines whether it is time to start charging the battery 21 based on the acquired charge / discharge plan and the GPS time acquired by the in-vehicle communication device 202 (step S110). If it is not time to start charging the battery 21 (step S110: NO), the charge / discharge ECU 201 ends the routine of FIG. 3 at that point in time, and starts executing the routine of FIG. 3 again after a predetermined time (infinite time) has elapsed.

[0020] Furthermore, when it is determined that the time to start charging the battery 21 has arrived (step S110: YES), the charge / discharge ECU 201 acquires the charging power Pc specified in the charge / discharge plan and acquires the total power consumption Ec of the auxiliaries calculated by the BEVECU 200 (step S120). Furthermore, the charge / discharge ECU 201 determines whether the acquired charging power Pc exceeds the total power consumption Ec of the auxiliaries (step S130). When the charging power Pc exceeds the total power consumption Ec of the auxiliaries (step S130: YES), the charge / discharge ECU 201 closes the charging relay CHR and controls the on-board charger / discharger 25 so that the battery 21 is charged in accordance with the charge / discharge plan (step S140). Then, the charge / discharge ECU 201 determines whether charging of the battery 21 has been completed for the corresponding term (frame) specified in the charge / discharge plan (step S150), and when charging of the battery 21 for the current term has been completed (step S150: YES), stops the on-board charger / discharger 25 and opens the charging relay CHR, and ends the routine of Figure 3.

[0021] On the other hand, if the charging power Pc specified in the charging / discharging plan is equal to or less than the total power consumption Ec of the auxiliaries (step S130: NO), the charging / discharging ECU 201 cancels the charging / discharging plan (step S160) and transmits a notification to the mobile terminal 30 of the user of the electrically powered vehicle 20 via the in-vehicle communication device 202 indicating that the charging / discharging plan from the management server 300 has been canceled, i.e., indicating that the incentive obtained when the battery 21 is charged according to the charging / discharging plan will be lost (reduced) due to the cancellation of the charging / discharging plan (step S170). Next, the charging / discharging ECU 201 closes the charging relay CHR and controls the in-vehicle charger / discharger 25 so that the battery 21 is charged with a maximum power that is determined to be greater than the total power consumption based on the current value from the power grid PS and the allowable charging power Win of the battery 21 (step S180). Then, the charge / discharge ECU 201 determines whether the SOC of the battery 21 has reached or exceeded a predetermined target value Sref (e.g., a value of approximately 70-80%) (step S190), and when the SOC of the battery 21 has reached or exceeded the target value Sref (step S190: YES), stops the on-board charger / discharger 25, opens the charging relay CHR, and ends the routine of FIG. 3.

[0022] As described above, when the charging power Pc of the battery 21 based on the power supplied from the power system PS (external) according to the charge / discharge plan predetermined by the management server 300 of the virtual power plant is equal to or less than the total power consumption Ec of the auxiliaries (steps S160-S190), the charge / discharge ECU 201 as the control device of the present disclosure cancels the charge / discharge plan and charges the battery 21 with power greater than the total power consumption Ec of the auxiliaries (steps S160-S190). As a result, even if at least one auxiliary consumes power from the battery 21 due to, for example, air conditioning the interior of the electric vehicle 20, temperature adjustment of the battery 21, or lighting (due to a door being ajar or forgotten to be turned off) when the battery 21 is being charged with power supplied from the power system PS, the SOC of the battery 21 can be kept sufficiently high by the power from the power system PS (external). As a result, it is possible to effectively prevent the SOC of the battery 21 from becoming insufficient while the electric vehicle 20 is traveling. In addition, when it is determined in step S130 that the charging power Pc of the battery 21 is equal to or less than the total power consumption Ec, instead of charging the battery 21 at the above-mentioned maximum power until the SOC becomes equal to or greater than the target value Sref, the charging / discharging plan may be canceled and the battery 21 may be charged at the maximum power for only the corresponding term (frame) specified in the charging / discharging plan.

[0023] Furthermore, the invention of the present disclosure is not limited to the above-described embodiment, and various modifications can be made within the scope of the present disclosure. Furthermore, the above-described embodiment is merely one specific form of the invention described in the Summary of the Invention, and does not limit the elements of the invention described in the Summary of the Invention. [Industrial Applicability]

[0024] The invention of the present disclosure can be used in the electric vehicle manufacturing industry and the like. [Explanation of symbols]

[0025] 20 Electric vehicle, 21 Battery, 22 Power control unit (PCU), 23 Bidirectional DC / DC converter, 24 High voltage auxiliary equipment, 25 On-board charger / discharger, 26 Charging / discharging inlet, 30 Mobile terminal, 200 Overall electronic control unit (BEVECU), 201 Charging / discharging electronic control unit (charging / discharging ECU), 202 On-board communication device, 300 Management server, MG Motor generator.

Claims

[Claim 1] A control device for an electric vehicle including a battery that is charged with power supplied from an external source in accordance with a predetermined charge / discharge schedule, and an auxiliary device that operates by consuming the power stored in the battery, A control device for an electric vehicle that, when charging power supplied to the battery in accordance with the charge / discharge plan is equal to or less than the power consumption consumed by the auxiliary equipment, cancels the charge / discharge plan and charges the battery with power greater than the power consumption.

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