Charging device, method for controlling charging device, computer program product, and storage medium

Abstract

The invention provides a charging device, a control method of the charging device, a computer program product, and a storage medium. A charging device is provided with: an inrush current prevention circuit having a pair of input terminals, a resistor, and a relay; 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 on the basis of 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 the secondary battery, the relay being in an off state in a state in which power is not supplied to the input terminal, and the charging circuit being in a state in which power is not supplied to the input terminal. The control circuit determines that the relay has failed when it is determined that the voltage detected by the voltage detection unit after a predetermined time has elapsed since the control for putting the relay in the closed state has been performed is a voltage in an amount corresponding to the voltage drop of the external AC power and the voltage drop of the resistor.

Description

Technical Field

[0001] This disclosure relates to a charging device, a control method for the charging device, and a program. Background Technology

[0002] Previously, there were known on-board charging devices that charged batteries from an external AC power source.

[0003] In the aforementioned conventional vehicle charging devices, a surge current prevention resistor is configured in parallel to prevent surge current from flowing to the vehicle charging device when connected to an external AC power source, and a relay (bypass relay) is configured to prevent AC current from flowing to the surge current prevention resistor during actual charging.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-016276 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, in the aforementioned conventional vehicle charging devices, after connecting to an external AC power source to charge the smoothing capacitor inside the vehicle charging device, control is performed to turn on the relay so as to supply power from the external AC power source without passing through the surge current prevention resistor.

[0009] Furthermore, in voltage sensors that detect the voltage of smoothing capacitors, AC voltage is detected even if the bypass relay fails to connect due to a malfunction, thus failing to detect situations where the relay cannot connect.

[0010] As a result, the following problems exist: charging cannot be performed via a relay without the surge current prevention resistor, and charging cannot be performed effectively.

[0011] The present invention was made in view of the above-mentioned problems, and its object is to provide a charging device, a control method for the charging device, and a program that can reliably detect faults in a relay connected in parallel with a surge current prevention resistor without increasing the number of components.

[0012] Solution for solving the problem

[0013] The charging device disclosed herein includes: a surge current prevention circuit for preventing surge current, the surge current prevention circuit having a pair of input terminals supplied with external AC power, a resistor connected at one end to one of the input terminals, and a relay connected at one end to one of the input terminals and at the other end to the other end of the resistor; a voltage detection unit for detecting the voltage between the other end of the resistor and the other input terminal; a control circuit for controlling the relay based on the voltage of the voltage detection unit; and a charging circuit for converting the AC power supplied via the surge current prevention circuit into DC power to charge a secondary battery, wherein, when no power is supplied to the input terminals, the relay is in an open state, and the control circuit determines that the relay is faulty if, after a predetermined time has elapsed since the control to close the relay, the voltage detected by the voltage detection unit is a voltage drop corresponding to the voltage drop of the external AC power and the voltage drop of the resistor.

[0014] The effects of the invention

[0015] According to the charging device disclosed herein, a fault in a relay connected in parallel with a surge current prevention resistor can be reliably detected without increasing the number of components, thereby preventing a fault in the surge current prevention resistor and thus preventing a fault in the charging device. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the implementation of an electric vehicle charging system.

[0017] Figure 2 This is a schematic diagram of the on-board charging device.

[0018] Figure 3 This is a diagram illustrating the operation when the power supply is single-phase AC power.

[0019] Figure 4 This is a diagram illustrating the operation when the power supply is three-phase AC power.

[0020] Figure 5 This is a flowchart of the implementation method. Detailed Implementation

[0021] Figure 1 This is a schematic diagram illustrating the implementation of an electric vehicle charging system.

[0022] The electric vehicle charging system 10 of the embodiment includes a charging station 11, a charging plug 12, and an electric vehicle 13.

[0023] The electric vehicle 13 is equipped with a charging socket 14 and an on-board charging device 15.

[0024] The charging station 11 is configured to receive power from commercial power sources and supply AC power to the electric vehicle 13 to charge the on-board battery of the electric vehicle 13.

[0025] Since the AC power is supplied via the charging socket 14, the on-board charging device 15 of the electric vehicle 13 performs AC / DC power conversion to charge the on-board battery of the electric vehicle 13.

[0026] Figure 2 This is a schematic diagram of the on-board charging device.

[0027] The on-board charging device 15 includes input terminals TI1 and TI2, surge current prevention circuit 21, first rectifier circuit 22, power factor correction circuit (PFC) 23, smoothing capacitor 24, inverter 25, transformer 26, second rectifier circuit 27, inductor 28, output terminals TO1 and TO2, relay drive circuit 29, first voltage detection unit 30, first current detection unit 31, second voltage detection unit 32, second current detection unit 33, and controller 34.

[0028] In the above structure, the input terminals TI1 and TI2 are electrically connected to the terminals of the charging socket 14, which is powered by the connected charging plug 12.

[0029] In addition, 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 constitute the charging circuit.

[0030] The surge current prevention circuit 21 is a circuit that prevents the current used to precharge the smoothing capacitor 24 from flowing in rapidly at the start of charging.

[0031] The surge current prevention circuit 21 includes a surge current prevention resistor (surge protection resistor) 41 and a relay 42.

[0032] Here, one end of the surge current prevention resistor 41 is connected to the input terminal TI1 to prevent the current used to precharge the smoothing capacitor 24 from being supplied as a surge current when AC power of a specified voltage is input from the input terminal TI1.

[0033] The relay 42 is connected in parallel with the surge current prevention resistor 41. After the smoothing capacitor 24 is pre-charged, it is in a closed state, supplying AC power as the object of power conversion to the subsequent circuit.

[0034] The first rectifier circuit 22 is configured as a diode bridge, which converts the input AC power into DC power and supplies it to the power factor improvement circuit 23.

[0035] The power factor improvement circuit 23 is controlled to make the power factor (the ratio of active power to apparent power) of the AC power supplied from the surge current prevention circuit 21 close to 1.

[0036] The power factor improvement circuit 23 includes an inductor (coil) 45 connected in series with the surge current prevention resistor 41 at one end, a diode 46 whose anode is connected to the other end of the inductor 45, and a switching transistor 47 whose anode is connected to the anode of the diode 46.

[0037] The smoothing capacitor 24 operates to smooth the DC voltage output from the power factor improvement circuit 23 and supply DC power at a specified fixed voltage to the subsequent circuits.

[0038] Inverter 25 converts the DC power supplied with a specified voltage via smoothing capacitor 24 into AC power and outputs it.

[0039] Transformer 26 converts the voltage of the input AC power into a specified output voltage based on the turns ratio of the primary winding to the secondary winding, and then supplies it to the second rectifier circuit 27.

[0040] The second rectifier circuit 27 is configured as a diode bridge, which converts the AC power transformed by the transformer 26 into DC power and supplies it to the vehicle battery BAT, which is the object of charging, through the output terminals TO1 and TO2 for charging.

[0041] The relay drive circuit 29 is a circuit that drives the relay 42 under the control of the controller 34 to perform the on / off action of the relay 42.

[0042] The first voltage detection unit 30 detects the AC voltage between the other end of the surge current prevention resistor 41 and the second input terminal TI2, and outputs the AC voltage as the first voltage detection signal V1 to the controller 34.

[0043] The first current detection unit 31 detects the alternating current from the other end of the surge current prevention resistor 41 toward the smoothing capacitor 24, and outputs the alternating current as the first current detection signal I1 to the controller 34.

[0044] The second voltage detection unit 32 detects the terminal voltage (DC voltage) of the smoothing capacitor 24 and outputs the terminal voltage as the second voltage detection signal V2 to the controller 34.

[0045] The second current detection unit 33 detects the DC current flowing from the power factor improvement circuit 23 to the inverter 25 side, and outputs the DC current as the second current detection signal I2 to the controller 34.

[0046] After the charging socket 14 is connected to the vehicle charging device 15 and a predetermined pre-charging time has elapsed, the controller 34 uses the relay drive circuit 29 to control the relay 42 to be in the on state. If the controller detects that the relay 42 has not switched to the on state based on the input first current detection signal I1 and the first voltage detection signal V1, it sets the relay to be in the off state due to sticking abnormality and performs processing such as stopping the power supply to protect the surge current prevention resistor 41.

[0047] Furthermore, the specific method for detecting that relay 42 has not switched to the ON state, i.e., the relay is abnormally stuck in the OFF state, will be described in detail later.

[0048] In addition, the controller 34 uses the relay drive circuit 29 to control the relay 42 to be in the on state. When the relay 42 is detected to be in the on state based on the input first current detection signal I1 and first voltage detection signal V1, the controller controls the power factor improvement circuit 23 and the inverter 25 based on the second current detection signal I1 and the second voltage detection signal V2 to control the power supply to the transformer 26 side.

[0049] Here, the principle of relay shut-off adhesion abnormality detection is explained.

[0050] [1] When the power supply is single-phase AC power

[0051] Figure 3 This is a diagram illustrating the operation when the power supply is single-phase AC power.

[0052] exist Figure 3 In the diagram, the thick arrows schematically illustrate the flow of charging current through the surge current prevention resistor 41 when the pre-charged relay 42 is in the off state.

[0053] In this case, the voltage of the AC power (single-phase AC power) supplied from the charging station 11 when no current flows is used is set as ACVpre.

[0054] When the charging socket 14 is connected to the on-board charging device 15, the charging station 11 receives power from a commercial power source and begins supplying AC power at voltage ACVpre.

[0055] As a result, AC power is supplied to the first rectifier circuit via surge current prevention resistor 41.

[0056] The first rectifier circuit 22 performs AC / DC conversion to charge the smoothing capacitor 24.

[0057] At this time, if the voltage detected by the first voltage detection unit 30 is set to ACVchg, the resistance value of the surge current prevention resistor 41 is set to R1, and the current detected by the first current detection unit 31 is set to ACI, then the following formula holds true.

[0058] ACVpre≈ACVchg+R1·ACI

[0059] In other words, if the voltage drop of surge current prevention resistor 41 is continuously detected during charging, it can be known that a relay shut-off sticking abnormality has occurred.

[0060] [2] When the power supply is three-phase AC power

[0061] Figure 4 This is a diagram illustrating the operation when the power supply is three-phase AC power.

[0062] In this case, let's assume that in each of the phases L1 to L3 constituting the three-phase AC power, a circuit is formed that connects to the controller. Figure 2 The on-board charging device 15 shown has the same circuit structure and is equipped with a controller shared by all phases.

[0063] More specifically, the on-board charging device 15A, which receives three-phase AC power, has the same structure as the on-board charging device 15, and adopts a structure obtained by connecting the first charging unit 15L1 corresponding to phase L1, the second charging unit 15L2 corresponding to phase L2, and the third charging unit 15L3 corresponding to phase L3 in parallel.

[0064] exist Figure 5 In the diagram, the thick arrows schematically illustrate the flow of charging current through the surge current prevention resistor 41 when the pre-charged relay 42 is in the off state.

[0065] When any one of the phases L1 to L3 in the above structure operates normally, and the smoothing capacitor 24 is charged by AC / DC conversion with the corresponding first rectifier circuit 22, if the voltage corresponding to phase L1 detected by the first voltage detection unit 30 corresponding to phase L1 is set to L1_ACVchg, the voltage corresponding to phase L2 detected by the first voltage detection unit 30 corresponding to phase L2 is set to L2_ACVchg, and the voltage corresponding to phase L3 detected by the first voltage detection unit 30 corresponding to phase L3 is set to L3_ACVchg, then:

[0066] L1_ACVchg≈L2_ACVchg≈L3_ACVchg.

[0067] In contrast, if the relay 42 corresponding to phase L1 becomes in an abnormal state of relay disconnection sticking, and if the resistance value of the surge current prevention resistor 41 of each phase L1 to L3 is set to R1, and the current detected by the first current detection unit 31 corresponding to phase L1 is set to L1_ACI, then the following formula holds.

[0068] L2_ACVchg≈L3_ACVchg

[0069] ≈L1_ACVchg+R1·L1_ACI

[0070] Therefore, if the voltage drop of the surge current prevention resistor 41 corresponding to phase L1 during charging is continuously detected, it can be known that a relay shut-off sticking abnormality has occurred in the relay 42 corresponding to phase L1.

[0071] Next, the operation of the implementation method will be explained.

[0072] [1] First implementation method

[0073] This first embodiment is based on the case where the power supply is single-phase alternating current.

[0074] Figure 5 This is a flowchart of the implementation method.

[0075] When the charging socket 14 is not connected to the on-board charging device 15, the relay 42 is set to the off state.

[0076] Regarding the controller 34, the charging socket 14 is connected to the on-board charging device 15 (step S11). The controller (not shown) on the charging station 11 side notifies the allowable current value, and the controller 34 performs power supply preprocessing to request power supply from the charging station 11 (step S12).

[0077] Then, when the power supply preprocessing is complete, AC power is supplied from the charging station 11 via the charging socket 14 (step S13).

[0078] Therefore, by using the AC power supplied via the input terminals TI1 and TI2, an AC current flows through the surge current prevention resistor 41 to precharge the smoothing capacitor 24 (step S14).

[0079] More specifically, the AC power supplied via surge current prevention resistor 41 is rectified by the first rectifier circuit 22 into DC power.

[0080] The DC power output from the first rectifier circuit 22 precharges the smoothing capacitor 24 via the power factor improvement circuit 23.

[0081] At this time, the second voltage detection unit 32 measures the voltage between the terminals of the smoothing capacitor 24 and outputs the second voltage detection signal V2 to the controller 34.

[0082] In addition, the first voltage detection unit 30 measures the voltage at one end of the surge current prevention resistor 41 (equivalent to the voltage between the input terminals of the first rectifier circuit 22) and outputs the first voltage detection signal V1 to the controller 34.

[0083] In parallel, the controller 34 determines whether the voltage between the terminals of the smoothing capacitor 24 corresponding to the second voltage detection signal V2 has reached the specified pre-charge voltage and the pre-charge is completed (step S15).

[0084] In step S15, if the voltage between the terminals of the smoothing capacitor 24 corresponding to the second voltage detection signal V2 has not reached the specified pre-charge voltage and pre-charging has not been completed (step S15: "No"), the system enters a standby state.

[0085] In the determination in step S15, if the voltage between the terminals of the smoothing capacitor 24 corresponding to the second voltage detection signal V2 reaches the specified pre-charge voltage and pre-charging is completed (step S15: "Yes"), the controller 34 outputs a relay drive control signal SRD to the relay drive circuit 29 in order to switch the current path of the surge current prevention circuit from the surge current prevention resistor 41 to the relay 42 (step S16).

[0086] As a result, the relay drive circuit 29 operates to allow current to flow through the coil constituting the relay 42, causing the relay 42 to switch to the ON state.

[0087] Next, the controller 34 performs the charging operation of the vehicle battery BAT (step S17).

[0088] Then, when the voltage detected by the first voltage detection unit 30 is set to ACVchg, the resistance value of the surge current prevention resistor 41 is set to R1, and the current detected by the first current detection unit 31 is set to ACI, the controller 34 determines whether the following formula (1) is true (step S18).

[0089] ACVpre≈ACVchg+R1·ACI……(1)

[0090] In the judgment of step S18, if equation (1) is true (step S18: "Yes"), the relay 42 is in the off sticking abnormal state and the relay 42 cannot be switched to the on state. Therefore, the controller 34 interrupts charging to prevent the surge current prevention resistor 41 from being damaged due to overcurrent (step S22).

[0091] Then, the controller 34 sends an abnormal notification to the charging station 11 indicating that the relay 42 is stuck and disconnected (step S23), and the process ends.

[0092] On the other hand, in the judgment of step S18, equation (1) is not true, that is...

[0093] ACVpre≈ACVchg……(2)

[0094] If the condition is met (step S18: "No"), the controller 34 determines whether the charging of the vehicle battery BAT is complete (step S19). That is, it determines whether the vehicle battery BAT has reached the specified charging amount.

[0095] If the determination in step S19 indicates that charging has not yet ended (step S19: "No"), the controller 34 transfers the processing back to step S17 to continue charging the vehicle battery BAT (step S17).

[0096] On the other hand, in the judgment of step S19, if the vehicle battery BAT reaches the specified charging amount and the charging of the vehicle battery BAT ends (step S19: "Yes"), the controller 34 performs charging end processing such as cutting off the current supply (step S20), and sends a charging end notification to the charging station 11 indicating that charging has been completed normally, and ends the processing (step S21).

[0097] As explained above, according to this first embodiment, faults of the bypass relay installed in parallel with the surge current prevention resistor can be reliably detected without increasing the number of components, thereby preventing faults caused by overcurrent flowing through the surge current prevention resistor.

[0098] [2] Second implementation method

[0099] This second embodiment is based on the case where the power supply is three-phase alternating current.

[0100] Figure 5 This is a flowchart of the implementation method.

[0101] When the charging socket 14 is not connected to the on-board charging device 15, the relay 42 is set to the off state.

[0102] Regarding the controller 34, the charging socket 14 is connected to the on-board charging device 15 (step S11). The controller (not shown) on the charging station 11 side notifies the power supply information (voltage, current, etc.) and the intention to start power supply. The controller 34 then performs power supply preprocessing to receive power supply (step S12).

[0103] Then, when the power supply preprocessing is complete, three-phase AC power is supplied from the charging station 11 via the charging socket 14 (step S13).

[0104] In the following explanation, we will take phase L1 of the three phases L1, L2, and L3 that constitute a three-phase AC power supply as an example.

[0105] Using the AC power supplied via the input terminals TIL11 and TIL12 of the first charging unit 15L1 corresponding to the phase L1 constituting the three-phase AC power, an AC current flows through the surge current prevention resistor 41 to precharge the smoothing capacitor 24 (step S14).

[0106] More specifically, the AC power supplied via surge current prevention resistor 41 is rectified by the first rectifier circuit 22 into DC power.

[0107] The DC power output from the first rectifier circuit 22 precharges the smoothing capacitor 24 via the power factor improvement circuit 23.

[0108] At this time, the second voltage detection unit 32 measures the voltage between the terminals of the smoothing capacitor 24 and outputs the second voltage detection signal V2 to the controller 34.

[0109] In addition, the first voltage detection unit 30 measures the voltage at one end of the surge current prevention resistor 41 (equivalent to the voltage between the input terminals of the first rectifier circuit 22) and outputs the first voltage detection signal V1 to the controller 34.

[0110] In parallel, the controller 34 determines whether the voltage between the terminals of the smoothing capacitor 24 corresponding to the second voltage detection signal V2 has reached the specified pre-charge voltage and the pre-charge is completed (step S15).

[0111] In step S15, if the voltage between the terminals of the smoothing capacitor 24 corresponding to the second voltage detection signal V2 has not reached the specified pre-charge voltage and pre-charging has not been completed (step S15: "No"), the system enters a standby state.

[0112] In the determination in step S15, if the voltage between the terminals of the smoothing capacitor 24 corresponding to the second voltage detection signal V2 reaches the specified pre-charge voltage and pre-charging is completed (step S15: "Yes"), the controller 34 outputs a relay drive control signal SRD to the relay drive circuit 29 in order to switch the current path of the surge current prevention circuit from the surge current prevention resistor 41 to the relay 42 (step S16).

[0113] As a result, the relay drive circuit 29 operates to allow current to flow through the coil constituting the relay 42, causing the relay 42 to switch to the ON state.

[0114] Next, the controller 34 performs the charging operation of the vehicle battery BAT (step S17).

[0115] Then, with the voltage detected by the first voltage detection unit 30 of the first charging unit 15L1 set to L1_ACVchg, the voltage detected by the first voltage detection unit 30 of the second charging unit 15L2 set to L2_ACVchg, the voltage detected by the first voltage detection unit 30 of the third charging unit 15L3 set to L3_ACVchg, the resistance value of each surge current prevention resistor 41 set to R1, and the current detected by the first current detection unit 31 corresponding to phase L1 set to L1_ACI, the controller 34 determines whether the following formula (2-1) is true (step S18).

[0116] L2_ACVchg≈L3_ACVchg

[0117] ≈L1_ACVchg+R1·L1_ACI……(2-1)

[0118] In the judgment of step S18, if equation (2-1) is true (step S18: "Yes"), the relay 42 of the first charging unit 15L1 is in a closed sticking abnormality and the relay 42 cannot be switched to the closed state. Therefore, the controller 34 interrupts charging to prevent the surge current prevention resistor 41 of the first charging unit 15L1 from being damaged due to overcurrent (step S22).

[0119] Similarly, if the current detected by the first current detection unit 31 corresponding to phase L2 is L2_ACI, the controller 34 determines whether the following formula (2-2) is true (step S18).

[0120] L1_ACVchg≈L3_ACVchg

[0121] ≈L2_ACVchg+R1·L2_ACI……(2-2)

[0122] In the judgment of step S18, if equation (2-2) is true (step S18: "Yes"), the relay 42 of the second charging unit 15L2 is in a closed sticking abnormality and the relay 42 cannot be switched to the closed state. Therefore, the controller 34 interrupts charging to prevent the surge current prevention resistor 41 of the second charging unit 15L2 from being damaged due to overcurrent (step S22).

[0123] Similarly, when the current detected by the first current detection unit 31 corresponding to phase L3 is set as L3_ACI, the controller 34 determines whether the following formula (2-3) is true (step S18).

[0124] L1_ACVchg≈L2_ACVchg

[0125] ≈L3_ACVchg+R1·L3_ACI……(2-3)

[0126] In the judgment of step S18, if equation (2-3) is true (step S18: "Yes"), the relay 42 of the third charging unit 15L3 is in an abnormal off-hook state and cannot switch to the on state. Therefore, the controller 34 interrupts charging to prevent the surge current prevention resistor 41 of the third charging unit 15L3 from being damaged due to overcurrent (step S22).

[0127] The above description describes the case where the relay 42 of any one of the charging units 15L1 to 15L3 is experiencing a shut-off sticking abnormality. However, when the relay 42 of two or all of the corresponding charging units is experiencing a shut-off sticking abnormality, the voltage of the corresponding phase is the product of the resistance value of the surge current prevention resistor 41 and the current detected by the first current detection unit 31 corresponding to the sticking abnormality. Therefore, the abnormality can be detected in the same way.

[0128] Therefore, the controller 34 sends an abnormal notification to the charging station 11, indicating that the relay 42 of the charging unit corresponding to the detected abnormality is stuck and connected (step S23), and ends the process.

[0129] On the other hand, in the judgment of step S18, equations (2-1) to (2-3) are all invalid, that is...

[0130] L1_ACVchg≈L2_ACVchg≈L3_ACVchg……(3)

[0131] If the condition is met (step S18: "No"), the controller 34 determines whether the charging of the vehicle battery BAT is complete (step S19). That is, it determines whether the vehicle battery BAT has reached the specified charging amount.

[0132] If the determination in step S19 indicates that charging has not yet ended (step S19: "No"), the controller 34 transfers the processing back to step S17 to continue charging the vehicle battery BAT (step S17).

[0133] On the other hand, in the judgment of step S19, if the vehicle battery BAT reaches the specified charging amount and the charging of the vehicle battery BAT ends (step S19: "Yes"), the controller 34 performs charging end processing such as cutting off the current supply (step S20), and sends a charging end notification to the charging station 11 indicating that charging has been completed normally, and ends the processing (step S21).

[0134] As explained above, according to this second embodiment, faults of the bypass relay installed in parallel with the surge current prevention resistor can be reliably detected without increasing the number of components, thereby avoiding faults caused by overcurrent flowing through the surge current prevention resistor.

[0135] The above explanation describes the situation where charging is interrupted if any of the charging units 15L1 to 15L3 detects a relay shut-off sticking abnormality. However, for charging units where no abnormality is detected, charging can continue. Therefore, it is also possible to configure the charging power to decrease and the time until charging is completed to increase, but charging continues. In this case, the controller 34 only needs to notify the charging station 11 of the abnormality and then indicate that the charging time has increased.

[0136] As explained above, according to each embodiment, it is possible to reliably detect the faults of the relay that is connected in parallel with the surge current prevention resistor without increasing the number of components, prevent the surge current prevention resistor from malfunctioning, and thus prevent the charging device from malfunctioning, thereby improving user convenience.

[0137] Furthermore, the processing and control described in the embodiments, which are intended to be performed by multiple devices, can also be implemented by a single device. Conversely, the processing and control described, which are intended to be performed by a single device, can be configured to be implemented by multiple devices working together.

[0138] The controller that functions as the control unit in the above-described embodiment includes a control device such as an MPU, a storage device such as a ROM (Read-Only Memory) and RAM, and an input device such as an operation switch, and utilizes a typical computer hardware structure.

[0139] The program executed by the controller, which functions as the control unit in this embodiment, can also be provided as an installable or executable file on a computer-readable recording medium such as a USB flash drive, an SSD, or a DVD (Digital Versatile Disk).

[0140] Alternatively, the program executed by the controller, which functions as the control unit in this embodiment, can be stored on a computer connected to a network such as the Internet and provided by downloading it via the network. Alternatively, the program executed by the controller, which functions as the control unit in this embodiment, can be provided or distributed via a network such as the Internet.

[0141] Alternatively, the program for the controller, which functions as the control unit in this embodiment, can be pre-loaded into a ROM or the like.

Claims

1. A charging device comprising: A surge current prevention circuit for preventing surge current, the surge current prevention circuit having a pair of input terminals supplied with external AC power, a resistor connected at one end to one of the input terminals, and a relay connected at one end to one of the input terminals and at the other end to the other end of the resistor. A voltage detection unit that detects the voltage between the other end of the resistor and another of the input terminals; The control circuit controls the relay based on the voltage detected by the voltage detection unit. as well as The charging circuit converts the AC power supplied via the surge current prevention circuit into DC power to charge the secondary battery. Specifically, when no power is supplied to the input terminal, the relay is in the open state. If the control circuit determines that the voltage detected by the voltage detection unit after a predetermined time elapsed since the control to close the relay is a voltage drop relative to the external AC power and corresponding to the voltage drop of the resistor, then the relay is considered faulty.

2. The charging device according to claim 1, wherein, The charging circuit has a smoothing capacitor. After pre-charging the smoothing capacitor via the resistor, the control circuit controls the relay to be in a closed state.

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

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

5. The charging device according to claim 4, wherein, If the control circuit determines that a fault has occurred in any of the corresponding relays, it will interrupt all charging via the charging circuit.

6. The charging device according to claim 4, wherein, If the control circuit determines that a fault has occurred in any of the corresponding relays, it interrupts the charging via the charging circuit corresponding to the relay that has been determined to have failed, and continues the charging via the charging circuit corresponding to the relay that has been determined not to have failed.

7. A control method for a charging device, the charging device comprising: a surge current prevention circuit for preventing surge current, the surge current prevention circuit having a pair of input terminals supplied with external AC power, a resistor connected at one end to one of the input terminals, and a relay connected at one end to one of the input terminals and at the other end to the other end of the resistor; a voltage detection unit for detecting the voltage between the other end of the resistor and the other input terminal; and a control circuit for controlling the relay based on the voltage detected by the voltage detection unit. And a charging circuit, which converts the AC power supplied via the surge current prevention circuit into DC power to charge the secondary battery, in the control method, When no power is supplied to the input terminal, the relay is in the open state. The control method The process includes the following: The voltage detection unit detects the voltage after a predetermined time has elapsed since the control that closes the relay was initiated. as well as If the voltage detected by the voltage detection unit is determined to be a voltage drop relative to the external AC power and corresponding to the voltage drop of the resistor, the relay is deemed to be faulty.

8. A computer program product comprising a program for controlling a charging device via a computer, the charging device comprising: a surge current prevention circuit for preventing surge current, the surge current prevention circuit having a pair of input terminals supplied with external AC power, a resistor connected at one end to one of the input terminals, and a relay connected at one end to one of the input terminals and at the other end to the other end of the resistor; a voltage detection unit for detecting the voltage between the other end of the resistor and the other input terminal; and a control circuit for controlling the relay based on the voltage detected by the voltage detection unit. And a charging circuit, which converts the AC power supplied via the surge current prevention circuit into DC power to charge the secondary battery, wherein, When no power is supplied to the input terminal, the relay is in the open state. The program enables the computer to function as the following unit: A unit that detects the voltage after a predetermined time has elapsed since the control that closes the relay was initiated; as well as A unit that determines that the relay is faulty if the voltage detected by the voltage detection unit is a voltage drop relative to the external AC power and corresponds to the voltage drop of the resistor.

9. A storage medium storing a program for controlling a charging device via a computer, the charging device comprising: a surge current prevention circuit for preventing surge current, the surge current prevention circuit having a pair of input terminals supplied with external AC power, a resistor connected at one end to one of the input terminals, and a relay connected at one end to one of the input terminals and at the other end to the other end of the resistor; a voltage detection unit for detecting the voltage between the other end of the resistor and the other input terminal; and a control circuit for controlling the relay based on the voltage detected by the voltage detection unit. And a charging circuit, which converts the AC power supplied via the surge current prevention circuit into DC power to charge the secondary battery, wherein, When no power is supplied to the input terminal, the relay is in the open state. The program enables the computer to function as the following unit: A unit that detects the voltage after a predetermined time has elapsed since the control that closes the relay was initiated; as well as A unit that determines that the relay is faulty if the voltage detected by the voltage detection unit is a voltage drop relative to the external AC power and corresponds to the voltage drop of the resistor.

Images