Power conversion device for energy storage systems

Abstract

To provide a power conversion device for a power storage device that can more accurately detect output failures in the power conversion circuit. [Solution] The power conversion device of the energy storage device comprises a first control unit (MCU1), a power conversion circuit configured to output power to the energy storage device, a drive circuit that generates a drive signal for the power conversion circuit using power supply power (DCDC_POW), a cutoff circuit 60 that cuts off the supply of power supply power to the drive circuit, and a detection circuit 70. The detection circuit 70 is configured to output a cutoff signal to the first control unit (MCU1) based on the completion of the cutoff by the cutoff circuit 60. The cutoff signal indicates that the supply of power supply power to the drive circuit has been cut off.

Description

Technical Field

[0001] This disclosure relates to a power conversion device for a power storage device.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2021-176252 (Patent Document 1) discloses a technique for prohibiting the output of a power conversion circuit included in a charger when an abnormality occurs in the charger (on-vehicle charger) during charging of an on-vehicle battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, the detection value of a current sensor included in the charger is used to confirm whether the output of the power conversion circuit has stopped due to the above prohibition process. However, it is not always easy to confirm that the output of the power conversion circuit has stopped based on the detection value of the current sensor. For example, even when no current is flowing, the detection value of the current sensor may not become 0 A due to the offset error of the current sensor. Also, even if the detection value of the current sensor shows a value close to 0 A, there may be a possibility that a minute amount of current is flowing. Although it is conceivable to employ a current sensor with a small tolerance, such current sensors are difficult to obtain and manage and are expensive.

[0005] This disclosure has been made to solve the above problems, and an object thereof is to provide a power conversion device for a power storage device that can more accurately detect the stop of the output of a power conversion circuit.

Means for Solving the Problems

[0006] In one embodiment of the present disclosure, a power converter for an energy storage device is provided as described below. The power converter for an energy storage device comprises a first control device, a power conversion circuit configured to output power to the energy storage device, a drive circuit that generates a drive signal for the power conversion circuit using power supply power, a cutoff circuit that cuts off the supply of power supply power to the drive circuit, and a detection circuit. The detection circuit is configured to output a cutoff signal to the first control device based on the completion of the cutoff by the cutoff circuit. The cutoff signal indicates that the supply of power supply power to the drive circuit has been cut off. [Effects of the Invention]

[0007] According to this disclosure, it becomes possible to provide a power conversion device for an energy storage device that can more accurately detect the output stoppage of the power conversion circuit. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing the configuration of the charging system according to an embodiment of the present disclosure. [Figure 2] This figure shows an example of an electric vehicle equipped with the charging system shown in Figure 1. [Figure 3] This figure shows a part of the configuration of the charging circuit shown in Figure 1. [Figure 4] This diagram shows the configuration of the power supply circuit shown in Figures 1 and 2. [Figure 5] This flowchart shows a charging control method according to an embodiment of the present disclosure. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described in detail 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. Hereinafter, the electronic control unit may be referred to as "ECU (Electronic Control Unit)". The ECU comprises one or more processors and one or more memories.

[0010] Figure 1 shows the configuration of the charging system according to this embodiment. Referring to Figure 1, the charging system 1 comprises an AC charger 100, a battery 200, a vehicle ECU 300, a power supply circuit 400, an AC power supply 500, and a charging relay 31. The charging relay 31 is located between the AC charger 100 and the battery 200. The charging relay 31 is, for example, an electromagnetic mechanical relay. The charging relay 31 is controlled by the vehicle ECU 300.

[0011] AC power supply 500 is an AC power supply that supplies AC power to AC charger 100. AC charger 100 outputs charging power for battery 200. AC charger 100 includes a charging circuit 110, a capacitor 130, a charging ECU 150, a current sensor 151, and a voltage sensor 152. The charging circuit 110 converts the AC power supplied from AC power supply 500 into DC power (charging power). The charging circuit 110 includes a power conversion circuit 111, an isolation transformer 112, and a rectifier circuit 113. The isolation transformer 112 includes a primary coil 112a and a secondary coil 112b. Capacitor 130 is connected in parallel with battery 200.

[0012] The current sensor 151 detects the magnitude of the current flowing through the primary coil 112a. The value detected by the current sensor 151 may be used for diagnosing abnormalities in the power conversion circuit 111. The voltage sensor 152 detects the magnitude of the charging voltage output from the AC charger 100 to the battery 200. The charging voltage detected by the voltage sensor 152 corresponds to the voltage of the capacitor 130. The respective detection values ​​of the current sensor 151 and the voltage sensor 152 are input to the charging ECU 150 and transmitted from the charging ECU 150 to the vehicle ECU 300.

[0013] In this embodiment, the charging system 1 shown in Figure 1 is mounted on an electric vehicle, and the AC power supply 500 is configured to be detachable from the AC charger 100. In this embodiment, the AC power supply 500 is an EVSE (Electric Vehicle Supply Equipment).

[0014] Figure 2 shows an example of an electric vehicle equipped with the charging system shown in Figure 1. Referring to Figure 2 in conjunction with Figure 1, vehicle 2 is an electric vehicle equipped with an inlet 10 that can be electrically connected to an AC charger 100 and a monitoring unit 32 that monitors the status of the battery 200.

[0015] As shown in Figure 1, the connector of the charging cable connected to the AC power supply 500 (EVSE) is connected to the inlet 10, thereby electrically connecting the AC power supply 500 and the power conversion circuit 111. This makes it possible to supply power from the AC power supply 500 to the AC charger 100 (onboard charger) through the charging cable.

[0016] The battery 200 is a rechargeable battery, such as a lithium-ion battery, nickel-metal hydride battery, or sodium-ion battery. The type of rechargeable battery may be a liquid-type rechargeable battery or an all-solid-state rechargeable battery. Multiple rechargeable batteries may form a battery pack. The monitoring unit 32 includes various sensors that detect the state of the battery 200 (e.g., voltage, current, and temperature). The detection results of each sensor included in the monitoring unit 32 are output to the vehicle ECU 300. The vehicle ECU 300 and the monitoring unit 32 may function as a BMS (Battery Management System) that manages the State of Charge (SOC) of the battery 200, etc.

[0017] Vehicle 2 further comprises an MG (Motor Generator) 21, a PCU (Power Control Unit) 22, and an SMR (System Main Relay) 23. The SMR 23 is located in the circuit connecting the battery 200 and the PCU 22. The SMR 23 is, for example, an electromagnetic mechanical relay. The state of the SMR 23 (connected / disconnected) is controlled by the vehicle ECU 300. The SMR 23 is connected when the vehicle is running.

[0018] MG21 is driven by PCU22 and is configured to rotate the drive wheels 25 of the vehicle 2. PCU22 may include, for example, a control device including a processor, an inverter, and a converter (none of which are shown). The control device of PCU22 is configured to receive an instruction (control signal) from the vehicle ECU300 and control the inverter and converter of PCU22 according to the instruction. The output torque of MG21 is transmitted to the drive wheels 25 via the power transmission gear 24 that serves as a speed reducer. Also, MG21 is configured to perform regenerative power generation, for example, when the vehicle decelerates, and supply the generated power to the battery 200.

[0019] In this embodiment, the vehicle ECU300 includes a control circuit (hereinafter referred to as "MCU1"). Also, the charging ECU150 also includes a control circuit (hereinafter referred to as "MCU2"). Each of MCU1 and MCU2 may be an IC (integrated circuit) based on a microprocessor. The charging ECU150 and the vehicle ECU300 are connected to each other via the bus L1. The bus L1 may be a CAN (Controller Area Network) bus. A CGW (central gateway) may be provided between the charging ECU150 and the vehicle ECU300. Also, the vehicle ECU300 is connected to the power supply circuit 400 via the direct control line L2. The direct control line L2 is a direct control line that directly connects devices one-to-one. By using the direct control line L2 for transmitting control signals, the control speed is increased. The charging ECU150 drives the charging circuit 110 using the power supplied from the power supply circuit 400. The configuration of the power supply circuit 400 will be described later (see FIG. 4).

[0020] In this embodiment, the charging ECU 150 is configured to perform charging control of the battery 200. Specifically, when the vehicle 2 and the AC power supply 500 (FIG. 1) are electrically connected via a charging cable, the charging ECU 150 is activated. Then, when a predetermined charging start condition is satisfied, the vehicle ECU 300 connects the charging relay 31 and transmits a charging request signal to the charging ECU 150. When the charging ECU 150 receives the charging request signal, it starts external charging of the battery 200 (charging using power supplied from outside the vehicle) by controlling the charging circuit 110. During the execution of external charging, the charging relay 31 is maintained in the connected state, and the charging circuit 110 is controlled by the charging ECU 150. The power for external charging is supplied from the AC power supply 500 to the inlet 10 of the vehicle 2 and input to the charging circuit 110. Then, it is output from the charging circuit 110 to the battery 200. The charging ECU 150 stops charging the battery 200 in response to a request from the vehicle ECU 300.

[0021] The vehicle ECU 300 has a function (hereinafter also referred to as the "CHEN function") of prohibiting the output of the charging circuit 110 when an abnormality occurs in the AC charger 100 during charging of the battery 200. Specifically, when an abnormality occurs in the AC charger 100 during the execution of the above external charging, the vehicle ECU 300 transmits a prohibition signal to the power supply circuit 400. The prohibition signal is transmitted from the vehicle ECU 300 to the power supply circuit 400 through the Jika line L2. When the prohibition signal is input to the power supply circuit 400, the power for driving the power conversion circuit 111 is no longer output from the power supply circuit 400. As a result, the output of the power conversion circuit 111 stops, and no charging voltage is applied to the battery 200. According to such a CHEN function, the vehicle ECU 300 can directly stop charging the battery 200 without going through the charging ECU 150. By having such a CHEN function, the vehicle ECU 300 can quickly and surely prohibit charging of the battery 200 when an abnormality occurs in the AC charger 100 and suppress excessive charging of the battery 200.

[0022] Vehicle 2 further comprises an input device 410 and a notification device 420. The input device 410 outputs a signal to the vehicle ECU 300 in response to user input. The notification device 420 may include at least one of a display device (e.g., a touch panel display), a speaker, and a MIL (fault warning light). The notification device 420 may also be an instrument panel, a head-up display, or a car navigation system.

[0023] Figure 3 shows a part of the configuration of the charging circuit 110. The charging circuit 110 includes, for example, the power conversion circuit 111, isolation transformer 112, and rectifier circuit 113 shown in Figure 3.

[0024] Referring to Figure 3 along with Figure 1, the power conversion circuit 111 includes a filter 111a, an AC / DC conversion circuit 111b, and a DC / AC conversion circuit 111c. The filter 111a removes high-frequency noise contained in the AC power. The AC / DC conversion circuit 111b includes a single-phase bridge circuit and converts the AC power supplied from the AC power supply 500 (Figure 1) via the filter 111a into DC power. The DC / AC conversion circuit 111c includes a smoothing capacitor, a single-phase bridge circuit, and an inductor and converts the DC power output from the AC / DC conversion circuit 111b into AC power. The AC voltage output from the DC / AC conversion circuit 111c is applied to the primary coil 112a. The isolation transformer 112 transforms the voltage in a ratio corresponding to the turns ratio of the primary coil 112a and the secondary coil 112b. The transformed AC voltage is applied to the secondary coil 112b. The rectifier circuit 113 includes an inductor and a single-phase bridge circuit, which converts the AC voltage applied to the secondary coil 112b into DC power and outputs it to the capacitor 130. Each bridge circuit is composed of multiple connected switching elements.

[0025] Each switching element in the AC / DC conversion circuit 111b, the DC / AC conversion circuit 111c, and the rectifier circuit 113 is switched on / off by the MCU2 of the charging ECU 150. The configuration for the MCU2 to control the DC / AC conversion circuit 111c will be described below.

[0026] The single-phase bridge circuit of the DC / AC conversion circuit 111c is composed of switching elements SW1 to SW4. The DC / AC conversion circuit 111c is provided with a drive circuit 50 that generates drive signals for the switching elements SW1 to SW4. The drive circuit 50 generates the above drive signals using power supplied from the drive power supply unit P1 (Figure 4), which will be described later (hereinafter also referred to as "DCDC_POW"). In this embodiment, N-channel MOSFETs are used as each of the switching elements SW1 to SW4. "MOS" stands for metal-oxide-semiconductor, and "FET" stands for field-effect transistor. A MOSFET has a drain, a source, and a gate. Each of the switching elements SW1 to SW4 does not allow current to flow between the drain and source when no voltage is applied to the gate, but when a positive voltage is applied to the gate relative to the source, a drain current flows from the drain to the source. The drive circuit 50 includes transformers 51 to 54. Each of the transformers 51, 52, 53, and 54 generates a drive signal according to a control command (e.g., a pulse signal) received from the MCU2 and outputs the drive signal to the gates of the switching elements SW1, SW2, SW3, and SW4. As a result, the switching elements operate according to the control command output by the MCU2. Each of the transformers 51 to 54 is a transformer and may function as, for example, a pulse transformer. Note that each of the switching elements SW1 to SW4 is not limited to an N-channel MOSFET and can be changed as appropriate.

[0027] As will be described in detail later, in this embodiment, the CHEN function mentioned above cuts off the supply of power (DCDC_POW) to the drive circuit 50 of the DC / DC conversion circuit 111c. On the other hand, each of the AC / DC conversion circuit 111b and the rectifier circuit 113 is configured so that they do not stop operating due to the CHEN function. For example, the drive circuits (e.g., gate drive circuits) for switching control of each of the AC / DC conversion circuit 111b and the rectifier circuit 113 may be supplied with power separate from DCDC_POW. Alternatively, the MCU2 may directly apply a drive signal (e.g., a gate drive signal) to each switching element included in the AC / DC conversion circuit 111b and the rectifier circuit 113 without going through a drive circuit. However, the configuration is not limited to these, and the AC / DC conversion circuit 111b and the rectifier circuit 113 may also be provided with a drive circuit having the same configuration as the drive circuit 50 shown in Figure 3 (i.e., a drive circuit whose operation is stopped by the CHEN function).

[0028] The vehicle ECU 300 can use the detection value of the current sensor 151 included in the AC charger 100 to confirm whether the output of the charging circuit 110 has stopped due to the CHEN function described above. However, it is not always easy to detect with high accuracy that the output of the charging circuit 110 has stopped based on the detection value of the current sensor 151. For example, even if no current is flowing, the detection value of the current sensor 151 may not be 0A due to the offset error of the current sensor 151. Also, even if the detection value of the current sensor 151 shows a value close to 0A, there is a possibility that a small amount of current is flowing. Therefore, the vehicle ECU 300 detects the stoppage of the output of the charging circuit 110 in cooperation with the power supply circuit 400 described below.

[0029] Figure 4 shows the configuration of the power supply circuit 400 shown in Figures 1 and 2. The power supply circuit 400 comprises a cutoff circuit 60 and a detection circuit 70. The cutoff circuit 60 is configured to cut off the supply of power (DCDC_POW) to the drive circuit 50 shown in Figure 3 in response to a request from the MCU1 of the vehicle ECU 300. Specifically, the cutoff circuit 60 has a switch device 61 and a resistor element 62. The switch device 61 is configured to switch the connection / cutoff of the power line PL that supplies power (DCDC_POW) to the drive circuit 50 (Figure 3). The power line PL is an electric wire connecting the drive power supply unit P1 and the transformers 51-54 shown in Figure 3. The switch device 61 includes a photocoupler. This photocoupler includes a light-emitting diode 61a and a phototransistor 61b. The light-emitting diode 61a and the phototransistor 61b function as a light-emitting element and a light-receiving element, respectively. The resistor element 62 is connected to the MCU1 via a direct wire L2 (electric wire). The light-emitting diode 61a is connected to the direct wire L2 via a resistor 62. The phototransistor 61b is provided on the power line PL. The photocoupler can transmit signals while electrically isolating the power line PL and the direct wire L2. The switch device 61 is, for example, a normally closed type switch.

[0030] When the MCU1 outputs the aforementioned CHEN function prohibition signal (hereinafter also referred to as the "CHEN signal") to the direct line L2, the CHEN signal flows through the direct line L2 to the resistor 62 and the light-emitting diode 61a. The light-emitting diode 61a is energized by this CHEN signal (electrical signal) and emits light. The phototransistor 61b receives this light, and the phototransistor 61b enters an open state. With the power line PL interrupted, the supply of power (DCDC_POW) from the drive power supply unit P1 to the drive circuit 50 (Figure 3) is cut off.

[0031] The detection circuit 70 is configured to output a cutoff signal to the MCU1 based on the completion of the cutoff by the cutoff circuit 60. The cutoff signal indicates that the supply of power (DCDC_POW) to the drive circuit 50 (Figure 3) has been cut off. Specifically, the detection circuit 70 comprises a comparison circuit 71 and resistors 72-75. The comparison circuit 71 has input terminal T1 (first input terminal) and input terminal T2 (second input terminal). The detection circuit 70 also further comprises power terminals T11, T21 and ground terminals T12, T22. Power terminal T11 is connected to the drive power supply unit P1 via phototransistor 61b. Resistors 72 and 73 are provided on the wire connecting power terminal T11 and ground terminal T12. This wire branches between resistor 72 and resistor 73, and the branched circuit is connected to input terminal T1. Power terminal T21 is connected to the reference power supply unit P2. Resistor elements 74 and 75 are located on the wire connecting the power terminal T21 and the ground terminal T22. This wire branches between resistor element 74 and resistor element 75, and the branched circuit is connected to the input terminal T2. Ground terminals T12 and T22 are each connected to the ground section P3.

[0032] The drive power supply unit P1 outputs power supply power (DCDC_POW) for driving the DC / AC conversion circuit 111c to the power line PL. The power terminal T11 of the detection circuit 70 is connected to the power line PL. The reference power supply unit P2 outputs a reference voltage for the detection circuit 70 to the power terminal T21. In this embodiment, the power supply voltage output by the drive power supply unit P1 and the reference voltage output by the reference power supply unit P2 are the same voltage (hereinafter referred to as "Vdd"). The drive power supply unit P1 and the reference power supply unit P2 may each receive power from the auxiliary battery (not shown) of the vehicle 2.

[0033] The comparison circuit 71 is configured to output to the MCU1 the result of comparing the voltage input to input terminal T1 with the voltage input to input terminal T2. The comparison circuit 71 is, for example, an AND (logical conjunction) gate. The comparison circuit 71 outputs a value of "1" to the MCU1 when high-level signals (e.g., voltage signals above a predetermined threshold) are input to both input terminals T1 and T2, and outputs a value of "0" to the MCU1 when a low-level signal (e.g., a voltage signal below the threshold) is input to at least one of input terminals T1 and T2.

[0034] When phototransistor 61b is connected (closed), a voltage based on the power supply power (DCDC_POW) is input to input terminal T1. Specifically, the value obtained by dividing Vdd by resistors 72 and 73 (the first divided value of Vdd) is input to input terminal T1. The first divided value of Vdd corresponds to a high-level signal. On the other hand, when phototransistor 61b is disconnected, no voltage based on the power supply power (DCDC_POW) is input to input terminal T1. In this case, a voltage value corresponding to the ground section P3 (ground voltage) is input to input terminal T1. The ground voltage corresponds to a low-level signal.

[0035] A predetermined reference voltage is input to input terminal T2 regardless of the state (connected / disconnected) of the phototransistor 61b. Specifically, the value obtained by dividing Vdd by resistors 74 and 75 (the second divided value of Vdd) is input to input terminal T2. In this embodiment, the reference voltage input to input terminal T2 (the second divided value of Vdd) is set to match the first divided value of Vdd (the voltage based on DCDC_POW). That is, the second divided value of Vdd corresponds to a high-level signal.

[0036] Among the output signals of the comparison circuit 71, the signal indicating a value of "0" corresponds to the cutoff signal. While the phototransistor 61b is connected, the comparison circuit 71 outputs a signal indicating a value of "1", and the detection circuit 70 does not output a cutoff signal to the MCU1. The cutoff signal is generated when the phototransistor 61b cuts off, and the detection circuit 70 outputs a cutoff signal to the MCU1. If the MCU1 has not received a cutoff signal, it means that power is being supplied from the drive power supply unit P1 to the drive circuit 50 (Figure 3). If the MCU1 has received a cutoff signal, it means that the supply of charging power from the AC charger 100 to the battery 200 has stopped due to the output stop of the power conversion circuit 111.

[0037] Figure 5 is a flowchart showing the control performed by the vehicle ECU 300 during external charging. In the flowchart, "S" represents a step.

[0038] Referring to Figures 1 to 4 and Figure 5, in S10 the vehicle ECU 300 determines whether or not there is a malfunction in the AC charger 100. The vehicle ECU 300 may determine whether or not there is a malfunction in the AC charger 100 using at least one of the detection values ​​of each sensor included in the AC charger 100 (for example, current sensor 151 and voltage sensor 152) and the detection values ​​of each sensor included in the monitoring unit 32 (for example, current sensor, voltage sensor, and temperature sensor). For example, if any of the sensors included in the AC charger 100 outputs an abnormal detection value that is not seen under normal conditions, the vehicle ECU 300 may determine that there is a malfunction in the AC charger 100.

[0039] If the AC charger 100 is determined to be functioning correctly (NO in S10), the vehicle ECU 300 turns off the CHEN function in S11. When the CHEN function is off, the MCU 1 does not send a CHEN signal to the cutoff circuit 60. As a result, the light-emitting diode 61a does not emit light, and the phototransistor 61b remains connected. Subsequently, in S12, the vehicle ECU 300 determines whether the output signal of the comparison circuit 71 indicates a value of "0".

[0040] If the output signal of the comparison circuit 71 indicates a value of "1" (NO in S12), the vehicle ECU 300 determines in S31 whether charging is complete based on the state of the battery 200. For example, the vehicle ECU 300 may determine that charging is complete when the State of Charge (SOC) of the battery 200 reaches a target value. Alternatively, the vehicle ECU 300 may determine that charging is complete when a predetermined time has elapsed since the start of charging. If charging is not complete (NO in S31), the vehicle ECU 300 sends a command to the MCU2 in S32. The vehicle ECU 300 may determine the command to the MCU2 based on, for example, the state of the battery 200. The vehicle ECU 300 may request the MCU2 to provide the maximum power that the battery 200 can accept. Alternatively, the vehicle ECU 300 may request the MCU2 to suppress the charging power when, for example, the temperature or SOC of the battery 200 exceeds a predetermined value. Once the process in S32 is executed, the process returns to the first step (S10). If charging is complete (YES in S31), both ECUs 300 request the MCU 2 to stop charging (specifically, to stop the operation of the AC charger 100) in S33. This ends the charging of the battery 200. The process flow shown in Figure 5 then ends.

[0041] If the output signal of the comparison circuit 71 shows a value of "0" (YES in S12), the vehicle ECU 300 controls the notification device 420 in S13 to notify the user that there is an abnormality in the power supply circuit 400 (first abnormality notification). Specifically, the vehicle ECU 300 causes the notification device 420 to notify the AC charger 100 (power conversion circuit 111) of the loss of power supply. The first MIL (first lamp) may light up as a result of this notification process. The output signal of the comparison circuit 71 showing a value of "0" means that a cutoff signal has been input to the MCU1. Once the process in S13 is executed, the process proceeds to S33. The process in S33 described above is executed, and the charging of the battery 200 is completed. The processing flow shown in Figure 5 is also completed.

[0042] If the vehicle ECU 300 determines that there is an abnormality in the AC charger 100 (YES in S10), it turns on the CHEN function in S21. When the CHEN function is ON, the MCU 1 sends a CHEN signal to the cutoff circuit 60. As a result, the light-emitting diode 61a lights up and the phototransistor 61b enters a cutoff state. Since a cutoff signal is input to the MCU 1 in conjunction with the cutoff operation of the phototransistor 61b, the vehicle ECU 300 can more easily and reliably detect the output stoppage of the power conversion circuit 111 early.

[0043] Next, in S22, the vehicle ECU 300 determines whether the output signal of the comparison circuit 71 indicates a value of "1". If the output signal of the comparison circuit 71 indicates a value of "1" (YES in S22), the vehicle ECU 300 controls the notification device 420 in S23 so that the user is notified that there is an abnormality in the power supply circuit 400 (second abnormality notification). Specifically, the vehicle ECU 300 causes the notification device 420 to notify that the CHEN function is not working properly. The second MIL (second lamp) may light up as a result of this notification process. Once the process in S23 is executed, the process proceeds to S33. If the output signal of the comparison circuit 71 indicates a value of "0" (NO in S22), the process skips S23 and proceeds to S33. Then, the process in S33 described above is executed, and the charging of the battery 200 is completed. The processing flow shown in Figure 5 is also completed.

[0044] As described above, the power conversion device for the energy storage device according to this embodiment comprises a first control device (vehicle ECU 300), a power conversion circuit (charging circuit 110) configured to output power to the energy storage device (battery 200), a drive circuit 50 that generates a drive signal for the power conversion circuit using power from a power source, a cutoff circuit 60 that cuts off the supply of power from a power source to the drive circuit 50, and a detection circuit 70. The detection circuit 70 is configured to output a cutoff signal to the first control device based on the completion of the cutoff by the cutoff circuit 60. The cutoff signal indicates that the supply of power from a power source to the drive circuit 50 has been cut off. With this configuration, the first control device can more accurately detect when the output of the power conversion circuit has stopped.

[0045] Furthermore, when the drive circuit 50 receives a control command from the second control device (charging ECU 150), it generates a drive signal so that the switching elements SW1 to SW4 operate according to the control command. The cutoff circuit 60 is configured to cut off the power supply to the drive circuit 50 in response to a request (CHEN signal) from the first control device (vehicle ECU 300). With this configuration, the first control device can directly cut off the power to the drive circuit 50 without going through the second control device, and stop the power output from the power conversion circuit to the energy storage device.

[0046] In the above embodiment, the operation of all switching elements SW1 to SW4 included in the DC / AC conversion circuit 111c was prohibited in accordance with the prohibition signal output by the vehicle ECU 300. However, this is not limited to this, and the operation of only some of the switching elements SW1 to SW4 (for example, two or three) may be prohibited. For example, the operation of the minimum number of switching elements necessary to stop the output of the DC / AC conversion circuit 111c may be prohibited.

[0047] The switch device 61 may be, for example, a normally open type switch. The signal to stop the power supply to the light-emitting diode 61a may be a prohibit signal. It is not essential that the voltage of the drive power supply unit P1 and the voltage of the reference power supply unit P2 match. The comparator circuit 71 may be a comparator other than an AND gate. When a reference voltage is input from the reference power supply unit P2 to the input terminal T2, the comparator circuit 71 may output a high-level signal (a signal that is not a cutoff signal) to the MCU1 if the voltage input to the input terminal T1 is higher than the reference voltage, and the comparator circuit 71 may output a low-level signal (a cutoff signal) to the MCU1 if the voltage input to the input terminal T1 becomes lower than the reference voltage. Furthermore, even if the comparator circuit 71 changes its output voltage according to the difference between the voltage input to the input terminal T1 and the voltage input to the input terminal T2, the MCU1 can still determine whether or not the power line PL is cut off.

[0048] The above-described circuit configuration for the power conversion device of an energy storage device may be applied to devices other than AC chargers. The above-described circuit configuration may also be applied to wireless power transmission (WPT) devices. Furthermore, the power conversion device of an energy storage device may be used in vehicles other than automobiles (ships, airplanes, railway vehicles, etc.), unmanned mobile devices (autonomous transport vehicles, automatic vacuum cleaners, agricultural machinery, construction machinery, robots, drones, space probes, etc.), or buildings (houses, factories, etc.).

[0049] 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]

[0050] 1 Charging system, 2 Vehicle, 50 Drive circuit, 60 Cut-off circuit, 61 Switching device, 61a Light-emitting diode, 61b Phototransistor, 70 Detection circuit, 100 AC charger, 110 Charging circuit, 111c DC / AC conversion circuit, 150 Charging ECU, 200 Battery, 300 Vehicle ECU, 400 Power supply circuit, SW1~SW4 Switching elements.

Claims

1. First control device, A power conversion circuit configured to output power to a power storage device, A drive circuit that generates a drive signal for the power conversion circuit using power supply power, A cutoff circuit that cuts off the supply of the power to the drive circuit, A detection circuit configured to output a cutoff signal to the first control device based on the completion of cutoff by the cutoff circuit, Equipped with, The power converter of the energy storage device indicates that the cutoff signal indicates that the supply of power to the drive circuit has been cut off.

2. The power conversion device of the energy storage device further comprises a second control device for controlling the power conversion circuit, The power conversion circuit comprises a plurality of switching elements, The drive circuit is configured to generate the drive signal when it receives a control command from the second control device, so that the plurality of switching elements operate in accordance with the control command. The power conversion device for a power storage device according to claim 1, wherein the interruption circuit is configured to interrupt the supply of the power supply to the drive circuit in response to a request from the first control device.

3. The interruption circuit includes a switch device that switches between connecting and disconnecting the power line that supplies the power supply to the drive circuit. The detection circuit includes a comparison circuit having a first input terminal and a second input terminal. When the switch device is connected, a voltage based on the power supply is input to the first input terminal. When the switch device is in the off state, the voltage based on the power supply is not input to the first input terminal. A predetermined reference voltage is input to the second input terminal. The power conversion device for an energy storage device according to claim 1 or 2, wherein the comparison circuit is configured to output to the first control device the result of comparing the voltage input to the first input terminal with the voltage input to the second input terminal.

4. The predetermined reference voltage is set to match the voltage based on the power supply power. The power conversion device for a power storage device according to claim 3, wherein the comparison circuit is an AND gate.

5. The aforementioned switching device includes a photocoupler, The aforementioned photocoupler is A light-emitting diode that emits light in response to an electrical signal from the first control device, A phototransistor that switches the connection / disconnection of the power line in accordance with the light emitted by the light-emitting diode, A power conversion device for an energy storage device according to claim 3, including the power conversion device for the energy storage device.

Images