Control device for charging equipment, method for controlling charging equipment, and charging system

Abstract

To provide a control unit of charging equipment capable of stably charging even when the output voltage of the charging equipment becomes lower than the lower limit voltage.SOLUTION: EVSE 400 (ECU 401) calculates the output maximum power value SWmx and output maximum current value SImx using the battery voltage VB before charging starts (S13). The maximum output power value SWmx and the maximum output current value SImx are set, when the voltage VB is low, to be smaller than when the voltage VB is high. The current value Imax capable of being output is calculated based on the maximum output power SWmx. The current value Imax capable of being output is set, when the voltage VB is low, to be smaller than when the voltage VB is high (S14).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a control device for a charging facility, a control method for a charging facility, and a charging system.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2018-38198 (Patent Document 1) discloses a vehicle including a power storage device that can be charged using an external power source. In this Patent Document 1, the power storage device is charged according to the command value of the charging current or the charging power command value, whichever is smaller, where the charging current command value is set according to the output current of the charging stand and the charging power command value is set according to the required power of the vehicle.

Prior Art Documents

Patent Documents

[0003] [[ID=...]]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, information on the output current of the charging stand is provided from the charging stand to the vehicle. When components designed for a vehicle are utilized (converted) for components used in a charging stand, the output voltage of the charging stand may not satisfy the lower limit voltage of the specification value (design value) of the charging stand. When the output voltage of the charging stand becomes lower than the lower limit output voltage, the charging current output from the charging stand may become smaller than the output current by restricting the output to an allowable output even at a low voltage. In this case, the charging current output from the charging stand may deviate from the charging current command value, and charging may stop due to charging abnormality processing.

[0005] An object of the present disclosure is to enable stable charging even when the output voltage of the charging facility is lower than the lower limit voltage. [Means for solving the problem]

[0006] The charging equipment control device of this disclosure is a control device for a charging equipment that charges a battery mounted on a vehicle. The control device is configured to transmit to the vehicle the output current value that can be output from the charging equipment. The output current value is set to be smaller when the battery voltage is low compared to when the battery voltage is high.

[0007] In this configuration, the charging equipment's control unit transmits the maximum output current value that can be output from the charging equipment to the vehicle. The maximum output current value is set to be smaller when the battery voltage is low compared to when the battery voltage is high. For example, the lower the battery voltage, the smaller the maximum output current value. Therefore, when the voltage of the battery being charged (battery voltage) is low, the maximum output current value is small, so even if the output voltage of the charging equipment falls below the lower limit voltage, the range in which charging can be performed is widened, and stable charging becomes possible.

[0008] Preferably, the battery voltage may be the battery voltage before charging begins. The control device sets the output current value before charging the battery begins.

[0009] Generally, the battery voltage before charging begins is lower than the battery voltage after charging begins. Therefore, it is possible to prevent the output current value from becoming unnecessarily large and to enable stable charging. The battery voltage before charging begins may be detected by a voltage sensor installed in the charging equipment. Alternatively, at the start of charging, the vehicle may transmit information about the battery's normal operating lower limit voltage, and this normal operating lower limit voltage may be used as the battery voltage before charging begins.

[0010] Preferably, the control device may reset the output current value based on the battery voltage while the battery is charging.

[0011] In this configuration, the output current value is reset based on the battery voltage during charging. If the battery voltage rises during charging, the output current value increases, making it possible to shorten the charging time.

[0012] The charging equipment control method described herein is a method for controlling a charging equipment that charges a battery mounted on a vehicle. The control method includes acquiring the battery voltage, which is the voltage of the battery before charging begins, and transmitting to the vehicle the output current value that can be output from the charging equipment. The output current value is set to be smaller when the battery voltage is low compared to when the battery voltage is high.

[0013] This method acquires the battery voltage before charging begins and transmits the maximum output current value that the charging equipment can output to the vehicle. The maximum output current value is set to be smaller when the battery voltage is low compared to when the battery voltage is high. Therefore, when the battery voltage is low, the maximum output current value is small, which widens the charging range and allows for stable charging even when the output voltage of the charging equipment falls below the lower limit voltage.

[0014] The charging system of this disclosure comprises a vehicle equipped with an externally rechargeable battery, charging equipment that supplies charging power to the battery, and a control device that controls the charging equipment. The control device is configured to transmit to the vehicle an output current value that can be output from the charging equipment. The output current value is set to be smaller when the battery voltage is low compared to when the battery voltage is high. The vehicle sets a charging current command value based on the received output current value and transmits the charging current command value to the control device. The control device controls the charging equipment to supply charging power to the battery based on the received charging current command value.

[0015] In this configuration, the charging system's control unit transmits to the vehicle the maximum output current value that can be output from the charging equipment. Based on the received maximum output current value, the vehicle sets a charging current command value and transmits the charging current command value to the control unit. Based on the received charging current command value, the control unit controls the charging equipment to supply charging power to the battery. The maximum output current value is set to be smaller when the battery voltage is low compared to when the battery voltage is high. For example, the lower the battery voltage, the smaller the maximum output current value. Therefore, when the voltage of the battery being charged (battery voltage) is low, the maximum output current value is small, so even if the output voltage of the charging equipment falls below the lower limit voltage, the range in which stable charging can be achieved is widened, and stable charging becomes possible. [Effects of the Invention]

[0016] According to this disclosure, stable charging is possible even when the output voltage of the charging equipment falls below the lower limit voltage. [Brief explanation of the drawing]

[0017] [Figure 1] This is an overall configuration diagram of the charging system according to this embodiment. [Figure 2] This sequence shows an example of the charging start process executed in the ECU. [Figure 3] This is an example of a map showing the maximum output power and maximum output current. [Figure 4] This sequence shows an example of the charging start process in a modified example. [Figure 5] This flowchart shows an example of the charging process performed in the ECU. [Modes for carrying out the invention]

[0018] 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.

[0019] Figure 1 is an overall configuration diagram of a charging system 1 according to the present embodiment. The charging system 1 includes a vehicle V and a charging facility (EVSE: Electric Vehicle Supply Equipment) 400. In the present embodiment, the vehicle V is, for example, a battery electric vehicle (BEV) without an internal combustion engine. However, the present invention is not limited to this, and the vehicle V may be a plug-in hybrid electric vehicle (PHEV) equipped with an internal combustion engine, or may be another electric vehicle (xEV).

[0020] The vehicle V includes a motor generator (MG) 10 that is a rotating electric machine, a power transmission gear 20, drive wheels 30, a power control unit (PCU) 40, a system main relay (SMR) 50, a battery 100, a monitoring unit 200, and an electronic control unit (ECU) 300.

[0021] The MG 10 has functions as a motor and as a generator. The output torque of the MG 10 is transmitted to the drive wheels 30 via a power transmission gear 20 configured to include a reduction gear, a differential device, and the like.

[0022] During braking of the vehicle V, the MG 10 is driven by the drive wheels 30, and the MG 10 operates as a generator. Thereby, the MG 10 also functions as a braking device that performs regenerative braking to convert the kinetic energy of the vehicle V into electric power. The regenerative power generated by the regenerative braking force in the MG 10 is stored in the battery 100. The PCU 40 is a power conversion device that converts power bidirectionally between the MG 10 and the battery 100. The SMR 50 is electrically connected to a power line connecting the battery 100 and the PCU 40. When the SMR 50 is closed (ON), power is exchanged between the battery 100 and the PCU 40.

[0023] Battery 100 stores the power needed to drive the MG10. Battery 100 is a rechargeable DC power source (secondary battery), and is configured, for example, by stacking multiple single cells and electrically connecting them in series.

[0024] The monitoring unit 200 includes a voltage sensor 210 for detecting the voltage VB of the battery 100, a current sensor 220 for detecting the current IB that is input to and output from the battery 100, and a temperature sensor 230 for detecting the temperature TB of the battery 100.

[0025] The ECU 300 includes a CPU (Central Processing Unit) 301 and memory (including, for example, ROM (Read Only Memory) and RAM (Random Access Memory)) 302. Based on signals received from the monitoring unit 200, signals from various sensors (for example, vehicle speed, accelerator pedal position, etc.), and information such as maps and programs stored in the memory 302, the ECU 300 controls each device so that the vehicle V reaches a desired state. For example, based on signals received from the monitoring unit 200, the ECU 300 calculates the State of Charge (SOC) of the battery 100 and uses this SOC to control the charging and discharging of the battery 100. In addition, the ON / OFF state of the ignition switch (power switch) 250 is input to the ECU 300.

[0026] Vehicle V is equipped with an inlet 60, which is configured to allow connection of a connector 420 located at the end of the charging cable 410 of the EVSE400. When the connector 420 is connected to the inlet 60, the charging relay (CHR) 70 is closed by a command from the ECU300, enabling external charging of the battery 100. The EVSE400 includes a power conversion circuit that converts AC power supplied from, for example, the power grid into DC power. The EVSE400 includes an ECU401, which is a control device, and a voltage sensor 402 that detects the output voltage. The ECU401 includes a CPU and memory and controls the power output from the EVSE400 (the charging power of the battery 100).

[0027] When the power switch 250 is turned OFF and the EVSE400 connector 420 is connected to the inlet 60, charging of the battery 100 (external charging) begins.

[0028] Figure 2 shows a sequence of events illustrating an example of the charging start process performed in ECUs 300 and 401. When connector 420 is connected to inlet 60, communication is established between ECU 401 and ECU 300. This communication may be CAN (Controller Area Network) communication or PLC (Power Line Communication) communication. Furthermore, communication between ECU 401 and ECU 300 may be via short-range wireless communication.

[0029] Once communication is established between ECU401 and ECU300, information exchange processing is performed (steps 10 and 20 (hereinafter, steps are abbreviated as "S")). For example, vehicle V (ECU300) sends vehicle ID, charging voltage upper limit value CVmx, minimum current charging value, billing information, etc. to EVSE400 (ECU401). EVSE400 (ECU401) sends identification ID, version, output voltage value SVmx, billing information, etc. to vehicle V (ECU300).

[0030] Once the information exchange process is complete and the vehicle V is ready to begin charging, ECU300 sends a readiness notification to ECU401 (S21). Upon receiving the readiness notification from ECU300, ECU401 performs an insulation diagnosis, and if there are no abnormalities, sends a completion notification to ECU300 (S11).

[0031] When vehicle V (ECU300) receives a completion notification, it closes (turns on) CHR70 (S22). After sending the completion notification, EVSE400 (ECU401) detects the voltage VB of battery 100 using the voltage sensor 402 (S12). Alternatively, ECU300 may be configured to send an ON notification for CHR70, and ECU401 may detect the voltage VB using the voltage sensor 402 after receiving the ON notification. When CHR70 is in the closed state and no charging power is output from EVSE400, the voltage detected by the voltage sensor 402 is the voltage VB of battery 100.

[0032] The ECU 401 calculates the maximum output power SWmx and the maximum output current SImx based on the voltage VB detected by the voltage sensor 402 (S13).

[0033] Figure 3 shows an example of a map of the maximum output power SWmx and maximum output current SImx. This map is stored in the memory of the ECU401. In S13, this map is used to calculate the maximum output power SWmx (see dashed line) and maximum output current SImx (see solid line) based on the voltage VB. As shown in Figure 3, the maximum output power SWmx and maximum output current SImx are set to be smaller (output is limited) when the voltage VB is low compared to when the voltage VB is high. Alternatively, the maximum output power SWmx and maximum output current SImx may be set to be smaller as the voltage VB decreases, as shown by the dashed line.

[0034] Referring again to Figure 2, the ECU401 calculates the output current value Imax (S14). The output current value Imax is calculated using the formula: "Output current value Imax = Output power maximum value SWmx / min (Charging voltage upper limit value CVmx, Output voltage value SVmx)" (S14). min (Charging voltage upper limit value CVmx, Output voltage value SVmx) is the smaller of the charging voltage upper limit value CVmx and the output voltage value SVmx.

[0035] When the output current value Imax is greater than the output current maximum value SImx (a positive determination is made in S15), the ECU401 guards the output current value Imax by the output current maximum value SImx (in S16, the output current value Imax is set to the output current maximum value SImx).

[0036] Next, ECU401 notifies vehicle V (ECU300) of the output current value Imax (S17). Upon receiving the output current value Imax, ECU300 sets the charge current command value Ci. Then, ECU300 transmits the charge current command value Ci to ECU401 and starts the charge command (S23). The charge current command value Ci is a value less than or equal to the output current value Imax, and may be set according to the temperature TB of the battery 100, for example.

[0037] When ECU401 receives the charging current command value Ci (when the charging command is initiated), it starts outputting charging power from EVSE400. The current value of the charging power output from EVSE400 is the charging current command value Ci. This initiates charging (external charging) of battery 100.

[0038] According to this embodiment, the ECU401 of the EVSE400 transmits the output current value Imax, which is the maximum output current value that can be output from the EVSE400, to the vehicle V (ECU300). The output current value Imax is calculated using the formula: "Output current value Imax = Maximum output power SWmx / min (Upper charging voltage value CVmx, Output voltage value SVmx)". The maximum output power value SWmx is set to be smaller when the voltage VB of the battery 100 is low compared to when the voltage VB is high (see Figure 3). When the voltage VB of the battery 100 is low, the output current value Imax becomes smaller, so even if the output voltage of the EVSE400 is lower than the lower limit voltage, the charging range is widened and stable charging becomes possible.

[0039] Furthermore, in this embodiment, the maximum output current SImx is also set to be smaller when the voltage VB of the battery 100 is low compared to when the voltage VB is high (see Figure 3). Since the output current value Imax is guarded by the maximum output current SImx (see S15, S16), this configuration also reduces the output current value Imax when the voltage VB of the battery 100 is low. As a result, even when the output voltage of the EVSE400 falls below the lower limit voltage, the charging range is widened, and stable charging becomes possible.

[0040] In this embodiment, the voltage VB used to calculate the maximum output power SWmx and maximum output current SImx is the voltage of the battery 100 detected by the voltage sensor 402 before charging begins. The voltage VB before charging begins is lower than the voltage VB after charging begins. Therefore, it is possible to suppress the maximum output power SWmx and maximum output current SImx from becoming unnecessarily large, and as a result, it is possible to suppress the output current value Imax from becoming large, thus enabling stable charging.

[0041] (modified version) Figure 4 shows a sequence illustrating an example of the charging start process in a modified example. In the above embodiment, the voltage VB before charging started was detected using a voltage sensor 402 provided on the EVSE400. In the modified example, after communication between the ECU401 and the ECU300 is established, the EVSE400 (ECU401) calculates the output current value Imax during the information exchange process and transmits it to the ECU300.

[0042] In the modified information exchange process (S10,20), the vehicle V (ECU300) transmits information including the upper limit charge voltage CVmx and the lower limit voltage VBmn to the EVSE400 (ECU401). The lower limit voltage VBmn is the normal operating lower limit voltage of the battery 100, which is set based on the specifications of the battery 100 and the vehicle V, and is stored in the memory 302 of the ECU300. The normal operating lower limit voltage of the battery 100 may be, for example, a voltage corresponding to the lower limit of the State of Charge (SOC) at which normal driving of the vehicle V stops (discharge from the battery 100 stops).

[0043] In the modified information exchange process, ECU401 uses the received lower limit voltage value VBmn to calculate the maximum output power SWmx, the maximum output current SImx, and the outputable current value Imax (S13a~S16a). The processing in S13a~S16a is the same as the processing in S13~S16, using the lower limit voltage value VBmn as the voltage VB, and determining the maximum output power SWmx and maximum output current SImx from the map in Figure 3 (S13a). The outputable current value Imax is calculated using the formula: "Outputable current value Imax = Maximum output power SWmx / min (Upper limit charging voltage CVmx, Outputable voltage value SVmx)", and guard processing is performed with the maximum output current SImx (S14a~S16a). Then, ECU401 transmits the calculated outputable current value Imax, along with the identification ID, to ECU300.

[0044] In Figure 4, the processes S21, S11, S22, S23, and S18 are the same as the processes S21, S11, S22, S23, and S18 in Figure 3.

[0045] In this modified example as well, in vehicle V where the lower limit voltage value VBmn is low and the battery voltage VB is low, the output current value Imax becomes smaller, similar to the embodiment described above. Therefore, even when the output voltage of EVSE400 falls below the lower limit voltage, the charging range is widened, and stable charging becomes possible.

[0046] In the above embodiment, the output current value Imax was determined using the voltage VB before charging began. As the battery 100 charges, the voltage VB increases. The charging current command value Ci is set to be less than or equal to the output current value Imax. Therefore, by resetting the output current value Imax in accordance with the increase in voltage VB during the charging of the battery 100, it may be possible to shorten the charging time.

[0047] FIG. 5 is a flowchart showing an example of the charging process executed in the ECU 401. This flowchart is repeatedly processed at predetermined intervals during charging of the battery 100 (after the start of charging output in S18). For example, it is executed every time offset learning of the current sensor 220 of the monitoring unit 200 is performed. When offset learning is executed, charging of the battery 100 is temporarily stopped (charging power becomes 0). Note that the output available current value Imax notified to the ECU 300 in S17 of FIG. 2 is stored in the memory of the ECU 401 as the current value Imaxn.

[0048] In FIG. 5, in S30, the voltage VB of the battery 100 is acquired. The voltage VB may be a value detected by the voltage sensor 402, or may be the voltage VB detected by the voltage sensor 210 of the monitoring unit 200.

[0049] In S31, based on the voltage VB acquired in S30, the maximum output power SWmx and the maximum output current SImx are calculated. The process of S31 is the same as that of S13 (FIG. 2). In S32, the output available current value Imax is calculated, and in S33 and S34, the output available current value Imax is guarded by the maximum output current SImx. Since the processes of S32, S33, and S34 are the same as the processes of S14, S15, and S16 (FIG. 2), the description thereof is omitted.

[0050] In S35, it is determined whether or not the output available current value Imax calculated in S31 to S34 is greater than or equal to a predetermined value α than the current value Imaxn stored in the memory. When the output available current value Imax is greater than or equal to the predetermined value α than the current value Imaxn (Imax≧Imaxn + α), the process proceeds to S36. When the output available current value Imax is not greater than or equal to the predetermined value α than the current value Imaxn (Imax < Imaxn + α), the current routine ends. The predetermined value α may be set in advance in consideration of detection errors of the voltage VB or the like, and α = 0 may be used.

[0051] In S36, the output current value Imax is notified to the ECU300, and then the process proceeds to S37. In S37, the output current value Imax is stored in the memory of the ECU401 as the current value Imaxn (Imaxn ← Imax), and then the routine ends. When the ECU300 receives the output current value Imax, it resets the charge current command value Ci. The charge current command value Ci is a value less than or equal to the output current value Imax, and may be reset according to, for example, the temperature TB of the battery 100. Once the charge current command value Ci is reset, the EVSE400 outputs charge power corresponding to the reset charge current command value Ci.

[0052] By executing this charging process, the output current value Imax is reset based on the charging voltage VB. When the voltage VB rises during charging, the value of the output current value Imax increases, making it possible to shorten the charging time.

[0053] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention 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]

[0054] 1 Charging system, 10 Motor generator (MG), 20 Drive transmission gear, 30 Drive wheels, 40 PCU, 50 SMR, 60 Inlet, 70 CHR, 100 Battery, 200 Monitoring unit, 210 Voltage sensor, 220 Current sensor, 250 Ignition switch, 300 ECU, 301 CPU, 302 Memory, 400 EVSE, 401 ECU, 402 Voltage sensor, 420 Connector, V Vehicle.

Claims

1. A control device for charging equipment that charges a battery installed in a vehicle, The control device is configured to transmit to the vehicle the output current value that can be output from the charging equipment. A control device for charging equipment, wherein the output current value is set to be smaller when the battery voltage is low compared to when the battery voltage is high.

2. The battery voltage is the voltage of the battery before charging of the battery begins. The control device for a charging facility according to claim 1, wherein the control device sets the output current value before starting to charge the battery.

3. The control device for a charging device according to claim 2, wherein the control device resets the output current value based on the battery voltage while the battery is being charged.

4. A method for controlling a charging system that charges a battery installed in a vehicle, To obtain the battery voltage, which is the voltage of the battery before charging of the battery begins, This includes transmitting to the vehicle the output current value that can be output from the charging equipment, A control method for charging equipment, wherein the output current value is set to be smaller when the battery voltage is low compared to when the battery voltage is high.

5. A vehicle equipped with an externally rechargeable battery, A charging device that supplies charging power to the aforementioned battery, The charging equipment is controlled by a control device, The control device is configured to transmit to the vehicle the output current value that can be output from the charging equipment. The output current value is set to be smaller when the battery voltage is low compared to when the battery voltage is high. The vehicle sets a charging current command value based on the received outputtable current value and transmits the charging current command value to the control device. A charging system in which the control device controls the charging equipment to supply the charging power to the battery based on the received charging current command value.

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