Charging apparatus, method for controlling charging apparatus, and storage medium

Abstract

To surely detect a failure of a relay provided in parallel with a rush current prevention resistor.SOLUTION: The electric vehicle charging system includes an inrush current prevention circuit 22 having an inrush current prevention resistor 41 connected to an input terminal TI1 to which external AC power is supplied and a relay 42 having one end connected to the input terminal and the other end connected to the other end of the resistor to prevent an inrush current, a voltage detection unit 30 for detecting a voltage between the other end of the resistor and the other input terminal TI2, a control circuit for controlling the relay based on the voltage of the voltage detection unit, and a charging circuit for charging a secondary battery by converting AC power supplied via the inrush current prevention circuit into DC power. The relay is in an open state in a state where no power is supplied to the input terminal, and the control circuit determines that the relay has failed when the control circuit determines that the voltage detected by the voltage detector is a voltage corresponding to a voltage drop of the resistor with respect to the voltage of the external AC power after a lapse of a predetermined time from when the control circuit performs control to bring the relay into a closed state.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a charging device, a control method for a charging device, and a program. [Background technology]

[0002] 2. Description of the Related Art Conventionally, an on-vehicle charging device that charges a battery from an AC external power supply is known. In the above-mentioned conventional on-board charging device, an inrush current prevention resistor is provided to prevent inrush current from flowing into the on-board charging device when connected to an AC external power source, and a relay (bypass relay) is arranged in parallel with the inrush current prevention resistor to prevent AC current from flowing into the inrush current prevention resistor during actual charging. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-016276 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned conventional vehicle-mounted charging device, after connection to an external AC power supply and charging of the smoothing capacitor inside the vehicle-mounted charging device, control is performed to turn on the relay in order to supply power from the external AC power supply without passing through an inrush current prevention resistor. However, in the voltage sensor that detects the voltage of the smoothing capacitor, even if the bypass relay cannot be turned on due to a malfunction or the like, the AC voltage is detected, so it is not possible to detect that the relay cannot be turned on.

[0005] As a result, charging cannot be performed via a relay without passing through an inrush current prevention resistor, which poses a problem that charging cannot be performed effectively.

[0006] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a charging device, a control method for a charging device, and a program that can reliably detect a fault in a relay connected in parallel with an inrush prevention resistor without increasing the number of parts. [Means for solving the problem]

[0007] The charging device according to the present disclosure includes an inrush current prevention circuit for preventing inrush current, the inrush current prevention circuit having a pair of input terminals to which external AC power is supplied, a resistor having one end connected to one of the input terminals, and a relay having one end connected to one of the input terminals and the other end connected to the other end of the resistor, the inrush current prevention circuit having an inrush current prevention circuit, a voltage detection unit that detects a voltage between the other end of the resistor and the other input terminal, a control circuit that controls the relay based on the voltage of the voltage detection unit, and a charging circuit that converts AC power supplied via the inrush current prevention circuit into DC power and charges a secondary battery, the relay being in an open state when no power is supplied to the input terminals, and the control circuit determining that the relay has failed when it determines that the voltage detected by the voltage detection unit a predetermined time after the control circuit has closed the relay is a voltage equivalent to the voltage drop across the resistor compared to the voltage of the external AC power. [Effects of the Invention]

[0008] According to the charging device of the present disclosure, it is possible to reliably detect a failure of a relay connected in parallel with an inrush current prevention resistor without increasing the number of components, thereby preventing failure of the inrush current prevention resistor and, ultimately, the charging device. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic explanatory diagram of an electric vehicle charging system according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram of the in-vehicle charging device. [Figure 3] FIG. 3 is a diagram illustrating the operation when the supplied power is single-phase AC power. [Figure 4]FIG. 4 is a diagram illustrating the operation when the supplied power is three-phase AC power. [Figure 5] FIG. 5 is an operation flowchart of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] FIG. 1 is a schematic explanatory diagram of an electric vehicle charging system according to an embodiment. The electric vehicle charging system 10 of the embodiment includes a charging station 11 , a charging plug 12 , and an electric vehicle 13 . The electric vehicle 13 is equipped with a charging receptacle 14 and an on-board charging device 15 .

[0011] The charging station 11 is configured to receive power from a commercial power source, supply AC power to the electric vehicle 13, and charge the on-board battery of the electric vehicle 13.

[0012] The on-board charging device 15 of the electric vehicle 13 receives AC power via the charging receptacle 14 and performs AC / DC power conversion to charge the on-board battery of the electric vehicle 13 .

[0013] FIG. 2 is a schematic diagram of the in-vehicle charging device. The on-board charging device 15 includes input terminals TI1 and TI2, an inrush current prevention circuit 21, a first rectifier circuit 22, a power factor correction circuit (PFC) 23, a smoothing capacitor 24, an inverter 25, a transformer 26, a second rectifier circuit 27, an inductor 28, output terminals TO1 and TO2, a relay drive circuit 29, a first voltage detection unit 30, a first current detection unit 31, a second voltage detection unit 32, a second current detection unit 33, and a controller 34.

[0014] In the above configuration, input terminals TI1 and TI2 are electrically connected to terminals of charging receptacle 14 to which charging plug 12 is connected and to which power is supplied. The first rectifier circuit 22, the power factor correction circuit (PFC) 23, the smoothing capacitor 24, the inverter 25, the transformer 26, the second rectifier circuit 27, and the inductor 28 form a charging circuit.

[0015] The inrush current prevention circuit 21 is a circuit that prevents a current for precharging the smoothing capacitor 24 from suddenly flowing in when charging starts. The inrush current prevention circuit 21 includes an inrush current prevention resistor (inrush prevention resistor) 41 and a relay 42.

[0016] Here, one end of the inrush current prevention resistor 41 is connected to the input terminal TI1, and when AC power of a predetermined voltage starts to be input from the input terminal TI1, it prevents the current for precharging the smoothing capacitor 24 from being supplied as an inrush current.

[0017] The relay 42 is connected in parallel to the inrush current prevention resistor 41, and is closed after the smoothing capacitor 24 has been precharged, to supply the AC power to be converted to a subsequent circuit.

[0018] The first rectifier circuit 22 is configured as a diode bridge, and converts the input AC power into DC power, which is supplied to the power factor correction circuit 23 . The power factor correction circuit 23 performs control so that the power factor (the ratio of effective power to apparent power) of the AC power supplied from the inrush current prevention circuit 21 approaches unity.

[0019] The power factor correction circuit 23 includes an inductor (coil) 45 having one end connected to the inrush current prevention resistor 41 and connected in series with the inrush current prevention resistor 41, a diode 46 having an anode connected to the other end of the inductor 45, and a switching transistor 47 having one end connected to the anode of the diode 46.

[0020] The smoothing capacitor 24 operates to smooth the DC voltage output from the power factor correction circuit 23 and supply DC power of a predetermined constant voltage to the subsequent circuit. The inverter 25 converts DC power of a predetermined voltage supplied via the smoothing capacitor 24 into AC power and outputs it.

[0021] The transformer 26 converts the voltage of the input AC power into a predetermined output voltage in accordance with the winding ratio between the primary winding and the secondary winding, and supplies the output voltage to the second rectifier circuit 27 . The second rectifier circuit 27 is configured as a diode bridge, and converts the AC power transformed by the transformer 26 into DC power, which is supplied to the vehicle-mounted battery BAT to be charged via output terminals TO1 and TO2, thereby charging the battery.

[0022] The relay driving circuit 29 is a circuit that drives the relay 42 under the control of the controller 34 to turn the relay 42 on and off. The first voltage detection unit 30 detects the AC voltage between the other end of the inrush current prevention resistor 41 and the second input terminal TI2, and outputs it to the controller 34 as a first voltage detection signal V1.

[0023] The first current detector 31 detects an AC current flowing from the other end of the inrush current prevention resistor 41 toward the smoothing capacitor 24, and outputs the detected AC current to the controller 34 as a first current detection signal I1.

[0024] The second voltage detector 32 detects the terminal voltage (DC voltage) of the smoothing capacitor 24 and outputs it to the controller 34 as a second voltage detection signal V2.

[0025] The second current detection unit 33 detects the DC current flowing from the power factor correction circuit 23 to the inverter 25 side, and outputs the detected current to the controller 34 as a second current detection signal I2.

[0026] When charging receptacle 14 is connected to on-board charging device 15 and a predetermined pre-charge time has elapsed, controller 34 controls relay 42 via relay drive circuit 29 to turn on relay 42. If controller 34 detects that relay 42 does not transition to the on state based on the input first current detection signal I1 and first voltage detection signal V1, it treats this as a relay stuck-off abnormality and performs processing such as stopping power supply to protect inrush current prevention resistor 41.

[0027] A specific method for detecting that the relay 42 does not transition to the ON state, that is, a relay stuck-off abnormality, will be described in detail later.

[0028] The controller 34 also controls the relay 42 via the relay drive circuit 29 to turn it on, and when it detects that the relay 42 has transitioned to the on state based on the input first current detection signal I1 and first voltage detection signal V1, it controls the power factor correction circuit 23 and the inverter 25 based on the input second current detection signal I1 and second voltage detection signal V2 to control the power supplied to the transformer 26 side.

[0029] Here, the principle of relay off fixation abnormality detection will be explained. [1] When the power supply is single-phase AC power FIG. 3 is a diagram illustrating the operation when the supplied power is single-phase AC power. In FIG. 3, the thick arrows schematically illustrate the flow of charging current via inrush current prevention resistor 41 when relay 42 is in the OFF state after precharging.

[0030] In this case, the voltage of the AC power (single-phase AC power) supplied from charging station 11 when no current is flowing is defined as ACVpre. When charging receptacle 14 is connected to on-board charging device 15, charging station 11 receives power from the commercial power supply and starts supplying AC power at voltage ACVpre.

[0031] As a result, the current is supplied to the first rectifier circuit via the inrush current prevention resistor 41 . The first rectifier circuit 22 performs AC / DC conversion and charges the smoothing capacitor 24. In this case, if the voltage detected by the first voltage detection unit 30 is ACVchg, the resistance value of the inrush current prevention resistor 41 is R1, and the current detected by the first current detection unit 31 is ACI, the following equation holds: ACVpre ≒ ACVchg + R1 ACI In other words, if a voltage drop due to the inrush current prevention resistor 41 continues to be detected during charging, it is determined that a relay stuck off abnormality has occurred.

[0032] [2] When the power supply is three-phase AC power FIG. 4 is a diagram illustrating the operation when the supplied power is three-phase AC power. In this case, each of the phases L1 to L3 constituting the three-phase AC power has the same circuit configuration as the in-vehicle charging device 15 shown in FIG. 2 except for the controller, and one controller common to all phases is provided.

[0033] More specifically, the in-vehicle charging device 15A, which receives three-phase AC power, has the same configuration as the in-vehicle charging device 15, and is configured with a first charging unit 15L1 corresponding to phase L1, a second charging unit 15L2 corresponding to phase L2, and a third charging unit 15L3 corresponding to phase L3 connected in parallel.

[0034] In FIG. 5, the thick arrows schematically illustrate the flow of charging current via inrush current prevention resistor 41 when relay 42 is in the OFF state after precharging.

[0035] In the above configuration, when all of the phases L1 to L3 are operating normally, when the first rectifier circuits 22 corresponding to each phase perform AC / DC conversion to charge the smoothing capacitor 24, the voltage corresponding to phase L1 detected by the first voltage detection unit 30 corresponding to phase L1 is defined as L1_ACVchg, the voltage corresponding to phase L2 detected by the first voltage detection unit 30 corresponding to phase L2 is defined as L2_ACVchg, and the voltage corresponding to phase L3 detected by the first voltage detection unit 30 corresponding to phase L3 is defined as L3_ACVchg. L1_ACVchg≒L2_ACVchg≒L3_ACVchg This becomes:

[0036] In contrast, when the relay 42 corresponding to phase L1 is in a relay-off stuck abnormal state, the following equation holds if the resistance value of the inrush current prevention resistor 41 of each phase L1 to L3 is R1 and the current detected by the first current detection unit 31 corresponding to phase L1 is L1_ACI. L2_ACVchg ≒ L3_ACVchg ≒L1_ACVchg+R1·L1_ACI

[0037] Therefore, if a voltage drop due to the inrush current prevention resistor 41 corresponding to the phase L1 during charging continues to be detected, it is determined that a relay stuck off abnormality has occurred in the relay 42 corresponding to the phase L1.

[0038] Next, the operation of the embodiment will be described. [1] First embodiment In the first embodiment, the supplied power is single-phase AC power. FIG. 5 is an operation flowchart of the embodiment. When charging receptacle 14 is not connected to in-vehicle charging device 15, relay 42 is in the OFF state.

[0039] The controller 34 connects the charging receptacle 14 to the on-board charging device 15 (step S11), receives notification of the allowable current value from a controller (not shown) on the charging station 11 side, and performs pre-power supply processing in which the controller 34 requests power supply from the charging station 11 (step S12).

[0040] Then, when the pre-power supply process is completed, AC power is supplied from charging station 11 via charging receptacle 14 (step S13).

[0041] As a result, AC power supplied via the input terminals TI1 and TI2 causes an AC current to flow through the inrush current prevention resistor 41, precharging the smoothing capacitor 24 (step S14). More specifically, the AC power supplied via the inrush current prevention resistor 41 is rectified by the first rectifier circuit 22 to become DC power.

[0042] The DC power output from the first rectifier circuit 22 is passed through the power factor correction circuit 23 to precharge the smoothing capacitor 24 . At this time, the second voltage detector 32 measures the voltage across the smoothing capacitor 24 and outputs a second voltage detection signal V2 to the controller .

[0043] The first voltage detector 30 measures the voltage at one end of the inrush current prevention resistor 41 (corresponding to the voltage between the input terminals of the first rectifier circuit 22) and outputs a first voltage detection signal V1 to the controller .

[0044] In parallel with this, the controller 34 determines whether or not the voltage across the terminals of the smoothing capacitor 24 corresponding to the second voltage detection signal V2 has reached a predetermined precharge voltage and the precharge has been completed (step S15).

[0045] In the judgment of step S15, if the terminal voltage of the smoothing capacitor 24 corresponding to the second voltage detection signal V2 has not yet reached the predetermined precharge voltage and precharge has not yet been completed (step S15; No), the device enters a standby state.

[0046] If it is determined in step S15 that the inter-terminal voltage of the smoothing capacitor 24 corresponding to the second voltage detection signal V2 has reached a predetermined pre-charge voltage and pre-charging has been completed (step S15; Yes), the controller 34 outputs a relay drive control signal SRD to the relay drive circuit 29 to switch the current path of the inrush current prevention circuit from the inrush current prevention resistor 41 to the relay 42 (step S16).

[0047] As a result, the relay drive circuit 29 operates to pass a current through the coil that constitutes the relay 42, causing the relay 42 to transition to the on state. Next, the controller 34 performs a charging operation for the vehicle-mounted battery BAT (step S17).

[0048] Then, the controller 34 determines whether the following equation (1) holds when the voltage detected by the first voltage detection unit 30 is ACVchg, the resistance value of the inrush current prevention resistor 41 is R1, and the current detected by the first current detection unit 31 is ACI (step S18). ACVpre≒ACVchg+R1·ACI ……(1)

[0049] In the judgment of step S18, if the formula (1) is established (step S18; Yes), the controller 34 determines that the relay 42 is stuck off abnormally and cannot transition to the on state, and therefore suspends charging to prevent the inrush current prevention resistor 41 from being damaged by an overcurrent (step S22). Then, the controller 34 notifies the charging station 11 of an abnormality that the relay 42 is stuck on (step S23), and ends the process.

[0050] On the other hand, in the judgment of step S18, it is determined that the formula (1) is not satisfied, that is, ACVpre≒ACVchg ……(2) If the above expression is true (step S18; No), the controller 34 determines whether charging of the vehicle-mounted battery BAT has finished (step S19). That is, it determines whether the vehicle-mounted battery BAT has reached a predetermined charge amount.

[0051] If it is determined in step S19 that charging has not yet finished (step S19; No), the controller 34 shifts the process back to step S17 and continues charging the in-vehicle battery BAT (step S17).

[0052] On the other hand, if it is determined in step S19 that the in-vehicle battery BAT has reached a predetermined charge level and charging of the in-vehicle battery BAT has ended (step S19; Yes), the controller 34 performs charging termination processing such as cutting off the current supply (step S20), sends a charging termination notification to the charging station 11 indicating that charging has been completed normally, and ends the processing (step S21).

[0053] As described above, according to the first embodiment, it is possible to reliably detect a fault in a bypass relay provided in parallel with an inrush current prevention resistor without increasing the number of components, and as a result, it is possible to avoid a fault due to an overcurrent flowing through the inrush current prevention resistor.

[0054] [2] Second embodiment In the second embodiment, the supplied power is three-phase AC power. FIG. 5 is an operation flowchart of the embodiment. When charging receptacle 14 is not connected to in-vehicle charging device 15, relay 42 is in the OFF state.

[0055] The controller 34 receives notification of the power supply information (voltage, current, etc.) and the start of power supply from a controller (not shown) on the charging station 11 side when the charging receptacle 14 is connected to the on-board charging device 15 (step S11), and then performs pre-power supply processing in which the controller 34 responds to accept the power supply (step S12).

[0056] Then, when the pre-power supply process is completed, three-phase AC power is supplied from charging station 11 via charging receptacle 14 (step S13). In the following description, of the three phases L1, L2, and L3 that make up the three-phase AC power, the phase L1 will be described as an example.

[0057] AC power is supplied via input terminals TIL11 and TIL12 of the first charging unit 15L1 corresponding to phase L1 that constitutes the three-phase AC power, causing an AC current to flow through the inrush current prevention resistor 41, thereby precharging the smoothing capacitor 24 (step S14). More specifically, the AC power supplied via the inrush current prevention resistor 41 is rectified by the first rectifier circuit 22 to become DC power.

[0058] The DC power output from the first rectifier circuit 22 is passed through the power factor correction circuit 23 to precharge the smoothing capacitor 24 . At this time, the second voltage detector 32 measures the voltage across the smoothing capacitor 24 and outputs a second voltage detection signal V2 to the controller .

[0059] The first voltage detector 30 measures the voltage at one end of the inrush current prevention resistor 41 (corresponding to the voltage between the input terminals of the first rectifier circuit 22) and outputs a first voltage detection signal V1 to the controller .

[0060] In parallel with this, the controller 34 determines whether or not the voltage across the terminals of the smoothing capacitor 24 corresponding to the second voltage detection signal V2 has reached a predetermined precharge voltage and the precharge has been completed (step S15). In the judgment of step S15, if the terminal voltage of the smoothing capacitor 24 corresponding to the second voltage detection signal V2 has not yet reached the predetermined precharge voltage and precharge has not yet been completed (step S15; No), the device enters a standby state.

[0061] If it is determined in step S15 that the inter-terminal voltage of the smoothing capacitor 24 corresponding to the second voltage detection signal V2 has reached a predetermined pre-charge voltage and pre-charging has been completed (step S15; Yes), the controller 34 outputs a relay drive control signal SRD to the relay drive circuit 29 to switch the current path of the inrush current prevention circuit from the inrush current prevention resistor 41 to the relay 42 (step S16).

[0062] As a result, the relay drive circuit 29 operates to pass a current through the coil that constitutes the relay 42, causing the relay 42 to transition to the on state. Next, the controller 34 performs a charging operation for the vehicle-mounted battery BAT (step S17).

[0063] Then, the controller 34 determines whether the following equation (2-1) holds when the voltage detected by the first voltage detection unit 30 of the first charging unit 15L1 is L1_ACVchg, the voltage detected by the first voltage detection unit 30 of the second charging unit 15L2 is L2_ACVchg, the voltage detected by the first voltage detection unit 30 of the third charging unit 15L3 is L3_ACVchg, the resistance value of each inrush current prevention resistor 41 is R1, and the current detected by the first current detection unit 31 corresponding to phase L1 is L1_ACI (step S18). L2_ACVchg ≒ L3_ACVchg ≒L1_ACVchg+R1·L1_ACI ……(2-1)

[0064] If the determination in step S18 is that the formula (2-1) is true (step S18; Yes), the controller 34 determines that the relay 42 of the first charging unit 15L1 is stuck off abnormally and cannot transition to the on state, and therefore suspends charging to prevent the inrush current prevention resistor 41 of the first charging unit 15L1 from being damaged by an overcurrent (step S22).

[0065] Similarly, when the current detected by the first current detection unit 31 corresponding to the phase L2 is set to L2_ACI, the controller 34 determines whether or not the following equation (2-2) is established (step S18). L1_ACVchg ≒ L3_ACVchg ≒L2_ACVchg+R1·L2_ACI ……(2-2)

[0066] If the determination in step S18 is that the formula (2-2) is true (step S18; Yes), the controller 34 determines that the relay 42 of the second charging unit 15L2 is stuck off abnormally and cannot transition to the on state, and therefore suspends charging to prevent the inrush current prevention resistor 41 of the second charging unit 15L2 from being damaged by an overcurrent (step S22).

[0067] Similarly, when the current detected by the first current detection unit 31 corresponding to the phase L3 is set to L3_ACI, the controller 34 determines whether or not the following equation (2-3) is established (step S18). L1_ACVchg≒L2_ACVchg ≒L3_ACVchg+R1·L3_ACI ……(2-3)

[0068] If the determination in step S18 is that the formula (2-3) is true (step S18; Yes), the controller 34 determines that the relay 42 of the third charging unit 15L3 is stuck off abnormally and cannot transition to the on state, and therefore suspends charging to prevent the inrush current prevention resistor 41 of the third charging unit 15L3 from being damaged by an overcurrent (step S22).

[0069] The above explanation applies to the case where the relay 42 of the charging unit corresponding to any one of the phases of the charging units 15L1 to 15L3 is stuck off abnormally. However, if the relay 42 of the charging unit corresponding to two or all phases is stuck off abnormally, the voltage of the corresponding phase will be a value that includes the product of the resistance value of the inrush current prevention resistor 41 and the current detected by the first current detection unit 31 corresponding to the phase that is stuck off abnormally, so the abnormality can be detected in the same way.

[0070] Therefore, controller 34 notifies charging station 11 of the abnormality that relay 42 of the charging unit corresponding to the phase in which the abnormality was detected is stuck on (step S23), and ends the process.

[0071] On the other hand, in the judgment of step S18, none of the formulas (2-1) to (2-3) is satisfied, that is, L1_ACVchg≒L2_ACVchg≒L3_ACVchg……(3) If the above expression is true (step S18; No), the controller 34 determines whether charging of the vehicle-mounted battery BAT has finished (step S19). That is, it determines whether the vehicle-mounted battery BAT has reached a predetermined charge amount.

[0072] If it is determined in step S19 that charging has not yet finished (step S19; No), the controller 34 shifts the process back to step S17 and continues charging the in-vehicle battery BAT (step S17).

[0073] On the other hand, if it is determined in step S19 that the in-vehicle battery BAT has reached a predetermined charge level and charging of the in-vehicle battery BAT has ended (step S19; Yes), the controller 34 performs charging termination processing such as cutting off the current supply (step S20), sends a charging termination notification to the charging station 11 indicating that charging has been completed normally, and ends the processing (step S21).

[0074] As described above, according to the second embodiment, it is possible to reliably detect a fault in a bypass relay provided in parallel with an inrush current prevention resistor without increasing the number of components, and it is therefore possible to avoid a fault due to an overcurrent flowing through the inrush current prevention resistor.

[0075] In the above explanation, we have described a case where charging is interrupted when one of charging units 15L1 to 15L3 detects a relay stuck-off abnormality, but for charging units for which no abnormality is detected, charging is possible, so it is also possible to configure charging to continue although the charging power will be reduced and the time to complete charging will be longer. In this case, controller 34 notifies charging station 11 of the abnormality and then notifies that the time required for charging will be longer.

[0076] As described above, according to each embodiment, it is possible to reliably detect a failure of a relay connected in parallel to an inrush current prevention resistor without increasing the number of parts, thereby preventing failure of the inrush current prevention resistor and ultimately the charging device, thereby improving user convenience.

[0077] Furthermore, the processes and controls described in the embodiments as being performed by multiple devices may be integrated and realized in one device, and conversely, the processes and controls described as being performed by one device may be configured to be realized by multiple devices working together.

[0078] The controller functioning as the control unit in the above-described embodiment is equipped with a control device such as an MPU, a storage device such as a ROM (Read Only Memory) or RAM, and an input device such as an operation switch, and has a hardware configuration that utilizes a normal computer.

[0079] The program executed by the controller functioning as the control unit of this embodiment can also be provided by being recorded in an installable or executable file format on a computer-readable recording medium such as a USB memory, a semiconductor storage device such as an SSD, or a DVD (Digital Versatile Disk).

[0080] The program executed by the controller functioning as the control unit of this embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network.The program executed by the controller functioning as the control unit of this embodiment may be provided or distributed via a network such as the Internet.

[0081] Furthermore, the program for the controller that functions as the control unit of this embodiment may be provided by being pre-installed in a ROM or the like. [Explanation of symbols]

[0082] 10 Electric vehicle charging systems 11. Charging Station 12 Charging plug 13 Electric Vehicles 14 Charging Receptacle 15, 15A on-board charging device 15L1 1st charging unit 15L2 Second charging unit 15L3 3rd Charging Unit 21 Inrush current prevention circuit 22 1st rectifier circuit 23 Power factor correction circuit 24 smoothing capacitor 25 inverter 26 Transformer 27 Second rectifier circuit 28 Inductors 29 Relay drive circuit 30 First voltage detection unit 31 First current detection unit 32 Second voltage detection unit 33 Second current detection section 34 Controller 41 Inrush current prevention resistor 42 Relay 45 inductor 46 Diode 47 Switching Transistor ACVpre voltage BAT Vehicle battery I1 First current detection signal I2 Second current detection signal L1~L3 phase TI1 (one of the two) input terminals TI2 (other) input terminal TIL11 to TIL31 (one side) input terminal TIL12~TIL32 (other) input terminal V1 First voltage detection signal V2 Second voltage detection signal

Claims

1. an inrush current prevention circuit for preventing inrush current, the circuit comprising: a pair of input terminals to which external AC power is supplied; a resistor having one end connected to one of the input terminals; and a relay having one end connected to one of the input terminals and the other end connected to the other end of the resistor; a voltage detection unit that detects a voltage between the other end of the resistor and the other input terminal; a control circuit that controls the relay based on the voltage of the voltage detection unit; a charging circuit that converts AC power supplied via the inrush current prevention circuit into DC power and charges a secondary battery, the relay is in an open state when no power is supplied to the input terminal; the control circuit determines that the relay has failed when it determines that the voltage detected by the voltage detection unit after a predetermined time has elapsed since the control circuit performed control to close the relay is a voltage corresponding to a voltage drop across the resistor relative to the voltage of the external AC power; Charging device.

2. the charging circuit includes a smoothing capacitor; the control circuit precharges the smoothing capacitor via the resistor and then controls the relay to be in a closed state. The charging device according to claim 1 .

3. the external AC power is single-phase AC power, The control circuit interrupts charging via the charging circuit when it determines that the relay has failed. The charging device according to claim 1 .

4. the external AC power is three-phase AC power, the inrush current prevention circuit, the voltage detection unit, and the charging circuit are provided for each phase, The control circuit determines a fault in the corresponding relay for each phase. The charging device according to claim 1 .

5. When the control circuit determines that a relay corresponding to any of the phases has failed, the control circuit suspends charging via all of the charging circuits. The charging device according to claim 4.

6. When the control circuit determines that a relay corresponding to any of the phases has failed, it suspends charging via the charging circuit corresponding to the phase whose relay has been determined to have failed, and continues charging via the charging circuit corresponding to the phase whose relay has been determined to have not failed. The charging device according to claim 4.

7. a control method for a charging device having a pair of input terminals to which external AC power is supplied, a resistor having one end connected to one of the input terminals, and a relay having one end connected to one of the input terminals and the other end connected to the other end of the resistor, the control method comprising: a voltage detection unit detecting a voltage between the other end of the resistor and the other input terminal; a control circuit controlling the relay based on the voltage of the voltage detection unit; and a charging circuit converting AC power supplied via the inrush current prevention circuit into DC power and charging a secondary battery, the method comprising: the relay is in an open state when no power is supplied to the input terminal; a step of detecting a voltage after a predetermined time has elapsed since the control to close the relay is performed by the voltage detection unit; determining that the relay has failed when it is determined that the voltage of the external AC power is equal to the voltage drop of the resistor; A control method for a charging device comprising:

8. a control circuit for controlling the relay based on the voltage of the voltage detection unit; and a charging circuit for converting AC power supplied via the inrush current prevention circuit into DC power and charging a secondary battery, the control circuit comprising: an inrush current prevention circuit having a pair of input terminals to which external AC power is supplied, a resistor having one end connected to one of the input terminals, and a relay having one end connected to one of the input terminals and the other end connected to the other end of the resistor, the inrush current prevention circuit being used to prevent inrush current; a voltage detection unit for detecting a voltage between the other end of the resistor and the other input terminal; the relay is in an open state when no power is supplied to the input terminal; The computer means for detecting, via the voltage detection unit, a voltage after a predetermined time has elapsed since control was performed to close the relay; a means for determining that the relay has failed when it is determined that the voltage detected via the voltage detection unit is a voltage corresponding to a voltage drop across the resistor with respect to the voltage of the external AC power; A program that makes it work.

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