On-vehicle power converter

Abstract

To suppress increase of manufacturing costs of an on-vehicle power converter while suppressing flow of comparatively large rush curent to a smoothing capacitor when power is supplied from an external power supply to the on-vehicle power converter.SOLUTION: An on-vehicle power converter 1 is constituted by comprising: connectors CL, CN in which power to be output from an external power supply device Ch is input; an ACDC power conversion circuit 2; a smoothing capacitor Cs; a bidirectional DCDC power conversion circuit 3; switches SW1, SW2; and a control unit 4, wherein the control unit 4 supplies power to be output from a battery B to the smoothing capacitor Cs by controlling an operation of the bidirectional DCDC power conversion circuit 3 as maintaining the connectors CL, CN and the smoothing capacitor Cs in a cutoff state by the switches SW1, SW2 when it is determined that the on-vehicle power converter 1 is connected with an external power supply via the external power supply device Ch, and after that, transits the switches SW1, SW2 from the cutoff state to a conduction state.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an in-vehicle power converter.

Background Art

[0002] As an in-vehicle power converter, AC power output from an external power supply device such as a charging stand is rectified by an AC-DC power conversion circuit and smoothed by a smoothing capacitor to be converted into DC power. The DC power is converted into target DC power by a bidirectional DC-DC power conversion circuit, and the target DC power is supplied to a battery mounted on the vehicle. Further, in this in-vehicle power converter, before power is output from the external power supply device to the in-vehicle power converter, the smoothing capacitor is charged using the power output from the battery, so that when power is output from the external power supply to the in-vehicle power converter, a relatively large inrush current does not flow through the smoothing capacitor. As a related technique, there is Patent Document 1.

[0003] By the way, when the external power supply device does not have a function of controlling the power output timing, there is a possibility that power is output from the external power supply device to the in-vehicle power converter when the external power supply device and the in-vehicle power converter are connected to each other, that is, when the connector of the charging stand is inserted into the vehicle, and there is a possibility that the smoothing capacitor cannot be charged in advance.

[0004] Therefore, as another in-vehicle power converter, a circuit in which a resistor and a switch are connected in parallel in front of the smoothing capacitor is provided, the inrush current flowing from the external power supply device to the smoothing capacitor is limited by the resistor, and after the smoothing capacitor is charged, the switch is transitioned from the off state to the on state.

[0005] However, in other in-vehicle power converters, since it is necessary to provide a resistor and a switch to limit the inrush current flowing through the smoothing capacitor, there is a concern about an increase in manufacturing cost.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2022-54686 [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] An object according to one aspect of the present invention is to suppress an increase in the manufacturing cost of an in-vehicle power converter while suppressing a relatively large inrush current from flowing through a smoothing capacitor when power is supplied from an external power source to the in-vehicle power converter. [Means for Solving the Problems]

[0008] An in-vehicle power converter according to one form of the present invention is an in-vehicle power converter mounted on a vehicle, and includes a connector to which power output from an external power source is input, an ACDC power conversion circuit that rectifies the AC power input to the connector, a smoothing capacitor that smooths the power rectified by the ACDC power conversion circuit, a bidirectional DCDC power conversion circuit that converts the DC power smoothed by the smoothing capacitor into a target DC power and supplies it to a battery mounted on the vehicle, a switch provided between the connector and the smoothing capacitor, and a control unit that controls the operations of the ACDC power conversion circuit, the bidirectional DCDC power conversion circuit, and the switch.

[0009] When it is determined that the in-vehicle power converter is connected to the external power source, the control unit executes a battery charging preparation operation. The battery charging preparation operation controls the operation of the bidirectional DCDC power conversion circuit while keeping the connector and the smoothing capacitor in a disconnected state by the switch, so that the power output from the battery is supplied to the smoothing capacitor, and then the switch is transitioned from the disconnected state to the conducting state.

[0010] As a result, when power is supplied from an external power source to the in-vehicle power converter, for example, when connected to the external power source via an external power supply device and the external power supply device does not have a function to control the power output timing, even in such a case, it is possible to prevent power from being supplied from the external power source to the smoothing capacitor before the smoothing capacitor is sufficiently charged. Therefore, it is possible to suppress a relatively large inrush current from flowing through the smoothing capacitor. Also, since there is no need to provide a resistor to limit the inrush current flowing through the smoothing capacitor, the increase in the manufacturing cost of the in-vehicle power converter can be suppressed accordingly.

[0011] Also, in the battery charging preparation operation, when a predetermined time has elapsed after the power supply from the battery to the smoothing capacitor is started, the control unit transitions the switch from the off state to the on state. The predetermined time is equal to or longer than the time when the voltage value of the smoothing capacitor reaches a voltage value such that the current value flowing into the smoothing capacitor from the AC-DC power conversion circuit when the switch transitions to the on state is equal to or less than the allowable current value of the smoothing capacitor, and is equal to or shorter than the time when the voltage value reaches a voltage value equal to the peak value of the AC power input from the external power source or the voltage value of the DC power supplied from the AC-DC power conversion circuit.

[0012] As a result, it is possible to prevent the smoothing capacitor from being damaged even when the switch transitions from the off state to the on state. Therefore, the time from when the power supply from the battery to the smoothing capacitor is started until the switch transitions from the off state to the on state can be shortened, and thus the time taken from when the in-vehicle power converter is connected to the external power source until the charging of the battery is started can be shortened.

[0013] In addition, the in-vehicle power converter includes an in-vehicle power supply unit that supplies AC power to the interior of the vehicle. The AC-DC power conversion circuit is a bidirectional circuit capable of AC outputting the DC power on the smoothing capacitor side to the connector side. The switch is disposed between the connector and the AC-DC power conversion circuit and is configured to connect the AC-DC power conversion circuit to the connector or to connect the AC-DC power conversion circuit to the in-vehicle power supply unit.

[0014] Thereby, since the switch for connecting the AC-DC power conversion circuit to the connector or the in-vehicle power supply unit can be diverted to the switch for preventing an inrush current from flowing into the smoothing capacitor, an increase in the manufacturing cost of the in-vehicle power converter having a function of supplying power to the in-vehicle power supply unit can be suppressed.

[0015] In addition, the in-vehicle power converter includes the switch provided between the connector and the AC-DC power conversion circuit, a first voltage sensor provided between the switch and the connector, and a second voltage sensor provided between the switch and the AC-DC power conversion circuit. The control unit is configured to determine that the switch is welded when the first voltage detected by the first voltage sensor is equal to or higher than a first voltage threshold value and the second voltage detected by the second voltage sensor is equal to or higher than a second voltage threshold value when the switch disconnects the connector and the smoothing capacitor.

[0016] Thereby, it is possible to determine whether or not the switch is welded.

[0017] Further, the in-vehicle power converter includes a switch provided between the AC-DC power conversion circuit and the smoothing capacitor, a first voltage sensor provided between the switch and the AC-DC power conversion circuit, and a second voltage sensor provided between the switch and the bidirectional DC-DC power conversion circuit. When the switch disconnects the connector and the smoothing capacitor, the control unit determines that the switch is welded if the first voltage detected by the first voltage sensor is equal to or higher than a first voltage threshold value and the second voltage detected by the second voltage sensor is equal to or higher than a second voltage threshold value.

[0018] Thereby, it is possible to determine whether or not the switch is welded.

[0019] Further, the in-vehicle power converter includes a voltage sensor provided between the connector and the switch, and the control unit may be configured to shorten the predetermined time as the voltage detected by the voltage sensor is lower.

[0020] Thereby, as the output voltage of the external power supply is lower and the inrush current flowing into the smoothing capacitor is smaller, the time from when the power supply from the battery to the smoothing capacitor starts until the switch transitions from the off state to the on state can be shortened. Therefore, the time taken from when the in-vehicle power converter is connected to the external power supply until the charging of the battery starts can be shortened.

[0021] Further, in the in-vehicle power converter, the switch is disposed between the connector and the AC-DC power conversion circuit, and includes a capacitor provided between a bus bar provided between the switch and the AC-DC power conversion circuit and the ground. The switch may be disposed on all bus bars to which the capacitor is connected.

[0022] Accordingly, when an external power supply is connected to the ground and the switch is in the off state, even if the resistance value across the capacitor is relatively small, it is possible to turn off all the buses provided with the capacitor, and it is possible to suppress the flow of idle current to the ground via the external power supply, the connector, the bus, and the capacitor.

[0023] Further, when the power input to the connector is AC, the control unit may execute the battery charging preparation operation, and when the power input to the connector is DC, the control unit may be configured not to execute the battery charging preparation operation and keep the switch in the off state.

[0024] As a result, it is not necessary to separately provide a dedicated connector for inputting DC power supplied from the external power supply device, so that it is possible to suppress an increase in the manufacturing cost of the in-vehicle power converter. Further, when the power supplied from the external power supply device is DC power, it is not necessary to pre-charge the smoothing capacitor, so that a useless battery charging preparation operation can be omitted.

Advantages of the Invention

[0025] According to the present invention, it is possible to suppress an increase in the manufacturing cost of the in-vehicle power converter while suppressing a relatively large inrush current from flowing through the smoothing capacitor when power is supplied from an external power supply to the in-vehicle power converter.

Brief Description of the Drawings

[0026]

Figure 1

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Figure 12

Embodiments for Carrying Out the Invention

[0027] Hereinafter, embodiments will be described in detail with reference to the drawings.

[0028] FIG. 1 is a diagram showing an example of an in-vehicle power converter in the embodiment.

[0029] The in-vehicle power converter 1 shown in FIG. 1 is mounted on a vehicle Ve such as an electric vehicle or a plug-in hybrid vehicle, for example, and converts AC power supplied from an external power supply device Ch such as a charging stand into target DC power and supplies it to a battery B mounted on the vehicle Ve.

[0030] Note that the external power supply device Ch converts AC power output from an AC power supply P as an external power supply such as a commercial power supply into predetermined AC power and supplies it to the in-vehicle power converter 1.

[0031] Further, the battery B is a rechargeable battery such as a lithium-ion secondary battery, and is a main battery for supplying power to a drive device such as a traveling motor, or an auxiliary battery for supplying power to an electrical equipment such as an air compressor or a vehicle-side control unit Cv that controls the driving of the vehicle Ve.

[0032] Also, in the example shown in FIG. 1, the AC power output from the external power supply device Ch is supplied to the in-vehicle power converter 1 via the charging cable Ca. However, the AC power output from the external power supply device Ch may be supplied to the in-vehicle power converter 1 in a non-contact manner. In such a configuration, the in-vehicle power converter 1 is provided with a power receiving unit for receiving AC power in a non-contact manner, and the power receiving unit is assumed to be connected to the connectors CL and CN described later.

[0033] The in-vehicle power converter 1 further includes connectors CL, CN, and Cc, switches SW1 and SW2, an AC-DC power conversion circuit 2, a bidirectional DC-DC power conversion circuit 3, a smoothing capacitor Cs, current sensors Si1 and Si2, a voltage sensor Sv1 (first voltage sensor), a voltage sensor Sv2 (second voltage sensor), voltage sensors Sv3 and Sv4, and a control unit 4.

[0034] Connectors CL and CN receive AC power, which is the power output from the AC power supply P through the external power supply device Ch. Connector CL is connected to one terminal of the AC-DC power conversion circuit 2 via the bus bar (live wire) L11. Also, connector CL is connected to one output terminal OL of the external power supply device Ch via one power line in the charging cable Ca. Further, connector CN is connected to the other terminal of the AC-DC power conversion circuit 2 via the bus bar (neutral wire) L12. Also, connector CN is connected to the other output terminal ON of the external power supply device Ch via the other power line in the charging cable Ca. Connector Cc is connected to the control unit 4 via the signal line Lc. Also, connector Cc is connected to the terminal Oc of the external power supply device Ch via the signal line in the charging cable Ca. When the in-vehicle power converter 1 is connected to the external power supply device Ch via the charging cable Ca, the external power supply device Ch can supply power to the in-vehicle power converter 1, and communication becomes possible between the in-vehicle power converter 1 and the external power supply device Ch.

[0035] Switches SW1 and SW2 are constituted by, for example, electromagnetic relays of a contact. Switches SW1 and SW2 are provided between connectors CL and CN and a smoothing capacitor Cs described later. In the present embodiment, switch SW1 is provided on the bus bar L11 between connector CL and one terminal of the AC-DC power conversion circuit 2. Also, switch SW2 is provided on the bus bar L12 between connector CN and the other terminal of the AC-DC power conversion circuit 2. When switches SW1 and SW2 are in the ON state, connectors CL and CN and the AC-DC power conversion circuit 2 (smoothing capacitor Cs) are in a conductive state. Also, when at least one of switches SW1 and SW2 is in the OFF state, connectors CL and CN and the AC-DC power conversion circuit 2 (smoothing capacitor Cs) are in an open state. Note that a configuration may be adopted in which either one of switches SW1 and SW2 is omitted and only the other is provided. When both switches SW1 and SW2 are provided, even if one fails, the other can put connectors CL and CN and the smoothing capacitor Cs in an open state.

[0036] The AC-DC power conversion circuit 2 rectifies the AC power input to connectors CL and CN.

[0037] The smoothing capacitor Cs is provided between the AC-DC power conversion circuit 2 and the bidirectional DC-DC power conversion circuit 3, smooths the power rectified by the AC-DC power conversion circuit 2, and outputs it to the bidirectional DC-DC power conversion circuit 3. That is, one terminal of the smoothing capacitor Cs is connected to the bus bar (positive electrode wire) L21 that connects one terminal of the AC-DC power conversion circuit 2 and one terminal of the bidirectional DC-DC power conversion circuit 3 to each other, and the other terminal of the smoothing capacitor Cs is connected to the bus bar (negative electrode power supply) L22 that connects the other terminal of the AC-DC power conversion circuit 2 and the other terminal of the bidirectional DC-DC power conversion circuit 3 to each other.

[0038] The bidirectional DC-DC power conversion circuit 3 is provided between the smoothing capacitor Cs and the battery B, and when charging the battery B, it converts the DC power smoothed by the smoothing capacitor Cs into the target DC power and supplies it to the battery B.

[0039] The current sensor Si1 is composed of a Hall element, a shunt resistor, etc., detects the current I1 flowing through the bus bar L11, and sends the detected current I1 to the control unit 4.

[0040] The voltage sensor Sv1 is composed of a voltage dividing resistor, etc., detects the voltage V1 applied to the bus bars L11 and L12 between the connectors CL and CN and the switches SW1 and SW2, and sends the detected voltage V1 to the control unit 4.

[0041] The voltage sensor Sv2 is composed of a voltage dividing resistor, etc., detects the voltage V2 applied to the bus bars L11 and L12 between the switches SW1 and SW2 and the AC-DC power conversion circuit 2, and sends the detected voltage V2 to the control unit 4.

[0042] The voltage sensor Sv3 is composed of a voltage dividing resistor, etc., detects the voltage V3 applied to the smoothing capacitor Cs, and sends the detected voltage V3 to the control unit 4.

[0043] The current sensor Si2 is composed of a Hall element, a shunt resistor, etc., detects the current I2 flowing through the bidirectional DCDC power conversion circuit 3, and sends the detected current I2 to the control unit 4.

[0044] The voltage sensor Sv4 is composed of a voltage dividing resistor, etc., detects the voltage V4 output from the bidirectional DCDC power conversion circuit 3 when charging the battery B, and sends the detected voltage V4 to the control unit 4.

[0045] <An example of the ACDC power conversion circuit 2> Fig. 2(a) is a diagram showing an example of the ACDC power conversion circuit 2. In Fig. 2(a), the same components as those shown in Fig. 1 are denoted by the same reference numerals.

[0046] The ACDC power conversion circuit 2 shown in Fig. 2(a) is a so-called totem-pole type PFC (Power Factor Correction) circuit, and includes an inductor L and switching elements Q1 to Q4. The switching elements Q1 to Q4 are composed of, for example, MOSFETs (Metal Oxide Semiconductor Field-Effect Transistors).

[0047] One terminal of the inductor L is connected to the bus L11, and the other terminal of the inductor L is connected to the connection point between the source terminal of the switching element Q1 and the drain terminal of the switching element Q2. The connection point between the source terminal of the switching element Q3 and the drain terminal of the switching element Q4 is connected to the bus L12. The drain terminals of the switching elements Q1 and Q3 are connected to one terminal of the smoothing capacitor Cs via the bus L21, and the source terminals of the switching elements Q2 and Q4 are connected to the other terminal of the smoothing capacitor Cs via the bus L22.

[0048] When positive power is input from the bus bars L11 and L12 to the AC-DC power conversion circuit 2 (during the positive period of the alternating current), after the switching elements Q2 and Q4 turn on and the switching elements Q1 and Q3 turn off, the switching elements Q1 and Q4 turn on and the switching elements Q2 and Q3 turn off are repeated. Also, when negative power is input from the bus bars L11 and L12 to the AC-DC power conversion circuit 2 (during the negative period of the alternating current), after the switching elements Q1 and Q3 turn on and the switching elements Q2 and Q4 turn off, the switching elements Q2 and Q3 turn on and the switching elements Q1 and Q4 turn off are repeated. As a result, the AC power input to the AC-DC power conversion circuit 2 is improved in power factor and rectified.

[0049] Also, the AC-DC power conversion circuit 2 is a bidirectional circuit capable of AC outputting the DC power on the smoothing capacitor Cs side to the connector CL and CN sides.

[0050] <An example of the bidirectional DC-DC power conversion circuit 3> FIG. 2(b) is a diagram showing an example of the bidirectional DC-DC power conversion circuit 3. In FIG. 2(b), the same components as those shown in FIG. 1 are denoted by the same reference numerals.

[0051] The bidirectional DC-DC power conversion circuit 3 shown in FIG. 2(b) includes a transformer Tr, switching elements Q5 to Q8 constituting the primary-side bridge circuit of the transformer Tr, switching elements Q9 to Q12 constituting the secondary-side bridge circuit of the transformer Tr, and a capacitor C provided in the output stage. The switching elements Q5 to Q12 are constituted by, for example, MOSFETs.

[0052] The drain terminals of the switching elements Q5 and Q7 are each connected to one terminal of the smoothing capacitor Cs via the bus bar L21, and the source terminals of the switching elements Q6 and Q8 are each connected to the other terminal of the smoothing capacitor Cs via the bus bar L22. The connection point between the source terminal of the switching element Q5 and the drain terminal of the switching element Q6 is connected to one terminal of the primary coil Lt1 of the transformer Tr, and the connection point between the source terminal of the switching element Q7 and the drain terminal of the switching element Q8 is connected to the other terminal of the primary coil Lt1. The drain terminals of the switching elements Q9 and Q11 are each connected to one terminal of the capacitor C, and the source terminals of the switching elements Q10 and Q12 are each connected to the other terminal of the capacitor C. The connection point between the source terminal of the switching element Q9 and the drain terminal of the switching element Q10 is connected to one terminal of the secondary coil Lt2 of the transformer Tr, and the connection point between the source terminal of the switching element Q11 and the drain terminal of the switching element Q12 is connected to the other terminal of the secondary coil Lt2. One terminal of the capacitor C is connected to the positive terminal of the battery B shown in FIG. 1, and the other terminal of the capacitor C is connected to the negative terminal of the battery B.

[0053] Note that the circuit configuration of the bidirectional DCDC power conversion circuit 3 is not limited to the circuit configuration shown in FIG. 2(b) as long as it is a circuit configuration capable of converting the DC power smoothed by the smoothing capacitor Cs into the target DC power and supplying it to the battery B, and converting the DC power output from the battery B into a predetermined DC power and supplying it to the smoothing capacitor Cs.

[0054] <Regarding the configuration of the control unit 4> The control unit 4 shown in FIG. 1 is composed of a processor or a programmable device (such as an FPGA (Field Programmable Gate Array) or a PLD (Programmable Logic Device)), and controls the operations of the AC-DC power conversion circuit 2, the bidirectional DC-DC power conversion circuit 3, and the switches SW1 and SW2. Note that the operations of the AC-DC power conversion circuit 2 and the switches SW1 and SW2 may be controlled by a control unit different from the control unit 4. In this case, the control unit 4 cooperates with the other control unit to control the operation of the bidirectional DC-DC power conversion circuit 3.

[0055] <Regarding the operation of the control unit 4> 1) In advance, the connectors CL and CN and the smoothing capacitor Cs are in a disconnected state by the switches SW1 and SW2. First, when the control unit 4 determines that the in-vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch, while keeping the connectors CL and CN and the smoothing capacitor Cs in a disconnected state by the switches SW1 and SW2, the control unit 4 controls the operation of the bidirectional DC-DC power conversion circuit 3 to supply the power output from the battery B to the smoothing capacitor Cs and pre-charge the smoothing capacitor Cs. That is, when the control unit 4 determines that the in-vehicle power converter 1 is connected to the external power supply device Ch, the control unit 4 executes a battery charging preparation operation. The battery charging preparation operation is an operation in which, while keeping the connectors CL and CN and the smoothing capacitor Cs in a disconnected state by the switches SW1 and SW2, the power output from the battery B is supplied to the smoothing capacitor Cs by controlling the operation of the bidirectional DC-DC power conversion circuit 3, and then the switches SW1 and SW2 are changed from the off state to the on state to transition from the disconnected state to the conductive state. Note that it is assumed that the control unit 4 keeps the connectors CL and CN and the smoothing capacitor Cs in a disconnected state by the switches SW1 and SW2 from the end of the previous charging of the battery B until the pre-charging of the smoothing capacitor Cs is completed. Also, when pre-charging the smoothing capacitor Cs, the maximum value of the current flowing from the battery B to the smoothing capacitor Cs through the bidirectional DC-DC power conversion circuit 3 is, for example, a current equal to or less than the rated current of the smoothing capacitor Cs. 2) Next, when the pre-charging of the smoothing capacitor Cs is completed, the control unit 4 turns on both switches SW1 and SW2 to transition the in-vehicle power converter 1 from the disconnected state to the conductive state with respect to the AC power supply P. (End of battery charging preparation operation) 3) Next, the control unit 4 controls the operations of the AC-DC power conversion circuit 2 and the bidirectional DC-DC power conversion circuit 3 so that DC power corresponding to the target DC power sent from the vehicle-side control unit Cv is output to the battery B. 4) Then, when the target DC power sent from the vehicle-side control unit Cv becomes zero, or when a charging end instruction is sent from the vehicle-side control unit Cv, the control unit 4 stops the AC-DC power conversion circuit 2 and the bidirectional DC-DC power conversion circuit 3, and at the same time, the switches SW1 and SW2 are used to transition the connectors CL, CN and the smoothing capacitor Cs from the conductive state to the disconnected state.

[0056] <Example of the operation of the control unit 4 when it is determined that the in-vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch> When the control unit 4 detects the signals flowing through the signal lines and the signal line Lc in the charging cable Ca, it determines that the in-vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch. The above signals are, for example, the PISW signal. When the in-vehicle power converter 1 and the external power supply device Ch are connected via the charging cable Ca, a signal is input to the PISW terminal on the in-vehicle power converter 1 side, and the control unit 4 can detect the signal. Or, the above signal is, for example, the CPLT (Control Pilot Line) signal. When the in-vehicle power converter 1 and the external power supply device Ch are connected via the charging cable Ca, a signal is input to the CPLT terminal on the in-vehicle power converter 1 side, and the control unit 4 can detect the signal. Note that "determining that it is connected to the AC power supply P" includes the actual connected state.

[0057] Or, when the control unit 4 receives a charging start instruction sent from the vehicle-side control unit Cv, it determines that the in-vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch. Note that the vehicle-side control unit Cv sends a charging start instruction to the control unit 4 based on user operations, the remaining capacity of the battery B, etc.

[0058] Or, when AC power is output non - contact from the external power supply device Ch to the in - vehicle power converter 1, when communication for charging preparation is established between the control unit 4 and the external power supply device Ch, the control unit 4 determines that the in - vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch.

[0059] Or, when the control unit 4 receives from the vehicle - side control unit Cv that the vehicle Ve is approaching the external power supply device Ch, the control unit 4 determines that the in - vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch. Note that when the vehicle - side control unit Cv determines that the vehicle Ve is approaching the external power supply device Ch using the signal of the GPS (Global Positioning System) mounted on the vehicle Ve, the vehicle - side control unit Cv sends to the control unit 4 that the vehicle Ve is approaching the external power supply device Ch.

[0060] Or, when the control unit 4 receives from the vehicle - side control unit Cv that an operation or instruction for opening the cover covering the connectors CL, CN provided on the outer surface of the vehicle Ve from the closed state has been made or detected by a sensor (not shown), or when a sensor (not shown) detects that the driver or the like holds a wireless key and approaches the connectors CL, CN and receives that fact from the vehicle - side control unit Cv, the control unit 4 determines that the in - vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch.

[0061] Or, when the voltage sensor Sv1 detects an AC voltage V1 which is the applied voltage from the external power supply device Ch, the control unit 4 determines that the in - vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch.

[0062] <Example of the operation of the control unit 4 when the pre - charging of the smoothing capacitor Cs is completed> When the control unit 4 pre-charges the smoothing capacitor Cs, if the voltage V3 detected by the voltage sensor Sv3 becomes equal to or higher than the voltage threshold Vth3, the control unit 4 determines that the smoothing capacitor Cs is sufficiently charged (the smoothing capacitor Cs is filled with charge), and the switches SW1 and SW2 are used to transition the connectors CL and CN and the smoothing capacitor Cs from the off state to the on state. Note that the voltage threshold Vth3 is, for example, the peak value of the AC voltage applied to the buses L11 and L12, or the maximum value of the DC voltage applied to the buses L21 and L22 when AC power is output from the external power supply device Ch to the in-vehicle power converter 1. The voltage threshold Vth3 may be determined in advance, or may be determined or estimated from the value of the voltage sensor Sv1, or may be set to a value corresponding to the voltage output by the connected external power supply device Ch if the voltage is known.

[0063] Alternatively, when the control unit 4 pre-charges the smoothing capacitor Cs, if the current flowing from the battery B to the smoothing capacitor Cs detected by the current sensor Si2 becomes equal to or lower than the current threshold, the control unit 4 determines that the smoothing capacitor Cs is sufficiently charged, and the switches SW1 and SW2 are transitioned from the off state to the on state. Also, a current sensor connected in series with the smoothing capacitor Cs may be provided to detect the current flowing from the battery B to the smoothing capacitor Cs. Note that the current threshold is, for example, set to zero. Also, the current flowing from the battery B to the smoothing capacitor Cs may be integrated, and when the integrated amount exceeds a predetermined threshold, it may be determined that the smoothing capacitor Cs is sufficiently charged, and the switches SW1 and SW2 are used to transition the connectors CL and CN and the smoothing capacitor Cs from the off state to the on state.

[0064] Alternatively, in the battery charging preparation operation, when a predetermined time t has elapsed since the power supply from the battery B to the smoothing capacitor Cs was started, the control unit 4 determines that the smoothing capacitor Cs is sufficiently charged, and by transitioning the switches SW1 and SW2 from the off state to the on state, the connectors CL and CN and the smoothing capacitor Cs are transitioned from the disconnected state to the conductive state. The predetermined time t is equal to or longer than the time when the voltage value of the smoothing capacitor Cs reaches a voltage value such that the current value flowing from the AC-DC power conversion circuit 2 when the switches SW1 and SW2 are transitioned to the conductive state is equal to or less than the allowable current value of the smoothing capacitor Cs, and is equal to or shorter than the time when the voltage value reaches a voltage value equal to the peak value of the AC power input from the external power supply device Ch or the voltage value of the DC power supplied from the AC-DC power conversion circuit 2. These times may be determined experimentally in advance or may be calculated and determined according to the voltage of the battery B. By managing in this way by time, compared with the case of obtaining and determining the voltage of the smoothing capacitor Cs and the current flowing through the smoothing capacitor Cs, the time from when the power supply from the battery B to the smoothing capacitor Cs is started until the connectors CL and CN and the smoothing capacitor Cs are transitioned from the disconnected state to the conductive state by the switches SW1 and SW2 can be shortened by the time for converting the analog value detected by the voltage sensor and the current sensor into a digital value. Also, it is possible to prevent the smoothing capacitor from being damaged even when the switches SW1 and SW2 are transitioned from the disconnected state to the conductive state. That is, the time taken from when the in-vehicle power converter 1 is connected via the AC power supply P and the external power supply device Ch until the charging of the battery B is started can be shortened.

[0065] Further, the control unit 4 may be configured to change a predetermined time t (voltage threshold value Vth3, current threshold value, threshold value of a predetermined current integration amount) according to the voltage V1 detected by the voltage sensor Sv1. For example, specifically, it may be configured such that the lower the voltage V1, the shorter the predetermined time t. Usually, when the output voltage of the external power supply device Ch is relatively low, the current flowing from the external power supply device Ch to the in-vehicle power converter 1 becomes relatively small. Therefore, even if the predetermined time t is shortened, the current flowing from the external power supply device Ch to the smoothing capacitor Cs when the connectors CL, CN and the smoothing capacitor Cs are changed from the disconnected state to the conducting state by the switches SW1, SW2 can be made relatively small. As a result, the smoothing capacitor Cs can be charged by a necessary amount according to the output voltage of the external power supply device Ch, and compared with the case where a predetermined voltage, a predetermined current, and a predetermined time are determined according to the assumed maximum output voltage of the external power supply device Ch, the time from when the power supply from the battery B to the smoothing capacitor Cs is started until the connectors CL, CN and the smoothing capacitor Cs are changed from the disconnected state to the conducting state by the switches SW1, SW2 can be shortened. That is, the time taken from when the in-vehicle power converter 1 is connected via the AC power supply P and the external power supply device Ch until the charging of the battery B is started can be shortened.

[0066] <Example of the operation of the control unit 4 when determining the welding of the switches SW1, SW2> When AC power is output from the AC power supply P to the in-vehicle power converter 1 via the external power supply device Ch, if the switches SW1 and SW2 keep the connectors CL and CN and the smoothing capacitor Cs in the disconnected state, and when the voltage V1 detected by the voltage sensor Sv1 is equal to or higher than the voltage threshold Vth1 (first voltage threshold), and the voltage V2 detected by the voltage sensor Sv2 is equal to or higher than the voltage threshold Vth2 (second voltage threshold), the control unit 4 determines that the switches SW1 and SW2 are welded. Thereby, it is possible to determine whether the switches SW1 and SW2 are welded. When only one of the switches SW1 and SW2 is provided in the in-vehicle power converter 1, if the voltage V1 detected by the voltage sensor Sv1 is equal to or higher than the voltage threshold Vth1, and the voltage V2 detected by the voltage sensor Sv2 is equal to or higher than the voltage threshold Vth2, the control unit 4 determines that one of the switches is welded.

[0067] <Example of the operation of the control unit 4 after the switches SW1 and SW2 transition the connectors CL and CN and the smoothing capacitor Cs from the disconnected state to the conductive state> During charging of the battery B, the control unit 4 uses the current I1 detected by the current sensor Si1, the voltage V2 detected by the voltage sensor Sv2, and the voltage V3 detected by the voltage sensor Sv3 to control the driving of the switching elements Q1 to Q4 by the drive signals S1 to S4 so that the phase of the AC current input to the ACDC power conversion circuit 2 approaches zero, that is, the power factor of the AC power input to the ACDC power conversion circuit 2 approaches 1. Thereby, the rectified power with an improved power factor by the ACDC power conversion circuit 2 is output to the smoothing capacitor Cs.

[0068] Further, when the battery B is being charged, the control unit 4 controls the driving of the switching elements Q5 to Q8 by the drive signals S5 to S8 and controls the driving of the switching elements Q5 to Q12 by the drive signals S9 to S12 so that the DC power supplied from the bidirectional DCDC power conversion circuit 3 to the battery B follows the target DC power. The target DC power is set based on, for example, the voltage of the battery B when switching from constant current charging control to constant voltage charging control or the current flowing through the battery B when the constant voltage charging control ends. For example, the duty ratios of the drive signals S5 to S12 are each set to 50 [%]. Also, the drive signals S5 and S8 are made the same as each other, the drive signals S6 and S7 are made the same as each other, the drive signals S9 and S12 are made the same as each other, and the drive signals S10 and S11 are made the same as each other. Further, it is assumed that the phases of the drive signals S5 and S8 are different from each other by 180 degrees, and the phases of the drive signals S9 and S12 are different from each other by 180 degrees from the phases of the drive signals S10 and S11. Also, dead times are provided for the rise timings and fall timings of the drive signals S5 and S6, the rise timings and fall timings of the drive signals S7 and S8, the rise timings and fall timings of the drive signals S9 and S10, and the rise timings and fall timings of the drive signals S11 and S12, respectively.

[0069] <Example of the operation of the control unit 4 when outputting AC power from the connectors CL and CN> When the control unit 4 receives an instruction from a user or the like to output the power supplied from the battery B to the outside via the connectors CL and CN, the control unit 4 controls the operations of the ACDC power conversion circuit 2 and the bidirectional DCDC power conversion circuit 3 so that the DC power output from the battery B is converted into AC power and output to the outside via the connectors CL and CN.

[0070] The effects of the in - vehicle power converter 1 according to the present embodiment will be described. <Effect 1> When power is supplied from the AC power supply P to the in-vehicle power converter 1, for example, when it is connected to the AC power supply P via the external power supply device Ch and the external power supply device Ch does not have a function of controlling the power output timing (for example, when the charging control method of the external power supply device Ch is out of specification or when it is only Mode 1), etc. In this case, when the in-vehicle power converter 1 and the external power supply device Ch are connected, that is, when the connector of the charging stand is inserted into the vehicle Ve, there is a possibility that AC power is supplied from the AC power supply P to the in-vehicle power converter 1.

[0071] Therefore, in the in-vehicle power converter 1 of the embodiment, when it is determined that the in-vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch, a battery charging preparation operation is executed. Specifically, the power supply to the smoothing capacitor Cs is prohibited by keeping the connectors CL, CN and the smoothing capacitor Cs in a disconnected state by the switches SW1, SW2. Also, the smoothing capacitor Cs is pre-charged by supplying power from the battery B to the smoothing capacitor Cs. When the pre-charging of the smoothing capacitor Cs is completed, the connectors CL, CN and the smoothing capacitor Cs are transitioned from the disconnected state to the conducting state by the switches SW1, SW2 to permit the power supply from the AC power supply P to the smoothing capacitor Cs.

[0072] Thereby, even when the external power supply device Ch does not have a function of controlling the power output timing, etc., it is possible to suppress the power being supplied from the AC power supply P to the smoothing capacitor Cs via the external power supply device Ch before the smoothing capacitor Cs is sufficiently charged, so it is possible to suppress a relatively large inrush current from flowing through the smoothing capacitor Cs. Also, since there is no need to provide a resistor to limit the inrush current flowing through the smoothing capacitor Cs, the increase in the manufacturing cost of the in-vehicle power converter 1 can be suppressed accordingly.

[0073] <Effect 2> When the control unit 4 pre-charges the smoothing capacitor Cs, if the voltage V3 detected by the voltage sensor Sv3 becomes equal to or higher than the voltage threshold value Vth3, the control unit 4 determines that the smoothing capacitor Cs is sufficiently charged (the smoothing capacitor Cs is filled with charge), and may transition the connectors CL and CN and the smoothing capacitor Cs from the disconnected state to the conducting state by the switches SW1 and SW2.

[0074] Thereby, it is possible to surely suppress a relatively large inrush current from flowing through the smoothing capacitor Cs.

[0075] <Effect 3> In the battery charging preparation operation, after a predetermined time t has elapsed since the power supply from the battery B to the smoothing capacitor Cs is started, the connectors CL and CN and the smoothing capacitor Cs may be transitioned from the disconnected state to the conducting state. The predetermined time t is equal to or longer than the time when the voltage value of the smoothing capacitor Cs reaches a voltage value such that the current value flowing in from the AC-DC power conversion circuit 2 when transitioning to the conducting state by the switches SW1 and SW2 is equal to or less than the allowable current value of the smoothing capacitor Cs, and is equal to or shorter than the time when the voltage value reaches a voltage value equal to the peak value of the AC power input from the external power supply device Ch or the voltage value of the DC power supplied from the AC-DC power conversion circuit 2.

[0076] By managing in this way by time, compared with the case of obtaining and determining the voltage of the smoothing capacitor Cs and the current flowing through the smoothing capacitor Cs, the time until the connectors CL and CN and the smoothing capacitor Cs transition from the disconnected state to the conducting state can be shortened. Also, it is possible to prevent the smoothing capacitor from being damaged even when transitioning from the disconnected state to the conducting state by the switches SW1 and SW2. That is, the time taken from when the in-vehicle power converter 1 is connected via the AC power supply P and the external power supply device Ch until the charging of the battery B is started can be shortened.

[0077] <Effect 4> The predetermined time t (voltage threshold Vth3, current threshold, threshold of a predetermined current integration amount) may be changed according to the voltage V1 detected by the voltage sensor Sv1. For example, specifically, the lower the voltage V1, the shorter the predetermined time t may be.

[0078] Normally, when the output voltage of the external power supply device Ch is relatively low, the current flowing from the external power supply device Ch to the in-vehicle power converter 1 becomes relatively small. Therefore, the time from when the power supply from the battery B to the smoothing capacitor Cs starts until the connectors CL, CN and the smoothing capacitor Cs transition from the cut-off state to the conductive state by the switches SW1, SW2 can be shortened. That is, the time taken from when the in-vehicle power converter 1 is connected via the AC power supply P and the external power supply device Ch until the charging of the battery B starts can be shortened.

[0079] <Effect 5> The ACDC power conversion circuit 2 is a bidirectional circuit capable of AC outputting the DC power on the smoothing capacitor Cs side to the connectors CL, CN side. And when the control unit 4 receives an instruction from the user or the like to output the power supplied from the battery B to the outside via the connectors CL, CN, the DC power output from the battery B is converted into AC power and output to the outside via the connectors CL, CN. The operations of the ACDC power conversion circuit 2 and the bidirectional DCDC power conversion circuit 3 are controlled. Therefore, the in-vehicle power converter can be used not only for charging but also as a source of AC power.

[0080] <Effect 6> The in-vehicle power converter 1 includes switches SW1 and SW2, a voltage sensor Sv1, and a voltage sensor Sv2. Therefore, when AC power is output from the AC power supply P to the in-vehicle power converter 1 via the external power supply device Ch, and when the switches SW1 and SW2 keep the connectors CL and CN and the smoothing capacitor Cs in a disconnected state, if the voltage V1 detected by the voltage sensor Sv1 is equal to or higher than the voltage threshold Vth1 (first voltage threshold), and if the voltage V2 detected by the voltage sensor Sv2 is equal to or higher than the voltage threshold Vth2 (second voltage threshold), it is determined that the switches SW1 and SW2 are welded. Thereby, it is possible to determine whether or not the switches SW1 and SW2 are welded.

[0081] <Modification Example 1> FIG. 3 is a diagram showing Modification Example 1 of the in-vehicle power converter 1 of the embodiment. In FIG. 3, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. The in-vehicle power supply unit Co shown in FIG. 3 is an outlet terminal provided in the vehicle Ve and supplying AC power to the interior of the vehicle, to which a load (not shown) such as an electrical appliance is connected. When AC power is supplied from the in-vehicle power converter 1 to the in-vehicle power supply unit Co with a load connected to the in-vehicle power supply unit Co, it is assumed that the AC power is supplied to the load.

[0082] In the in-vehicle power converter 1 shown in FIG. 3, the difference from the in-vehicle power converter 1 shown in FIG. 1 is that switches SW3 and SW4 are provided instead of switches SW1 and SW2.

[0083] For example, the switches SW3 and SW4 are each constituted by an electromagnetic relay of a c-contact type, and the respective terminals COM of the switches SW3 and SW4 are connected to the AC-DC power conversion circuit 2, the respective terminals NC of the switches SW3 and SW4 are connected to the in-vehicle power supply unit Co, and the respective terminals NO of the switches SW3 and SW4 are connected to the connectors CL and CN.

[0084] When the COM terminals of switches SW3 and SW4 are connected to the NC terminals of switches SW3 and SW4 respectively, the AC-DC power conversion circuit 2 is connected to the in-vehicle power supply section Co. In this case, the connectors CL and CN and the smoothing capacitor Cs are in an off state by switches SW3 and SW4. Note that it can be said to be in an off state even if at least one of switches SW3 and SW4 is connected to the NC terminal.

[0085] When the COM terminals of switches SW3 and SW4 are connected to the NO terminals of switches SW3 and SW4 respectively, the AC-DC power conversion circuit 2 is connected to the connectors CL and CN. In this case, the connectors CL and CN and the smoothing capacitor Cs are in a conductive state by switches SW3 and SW4.

[0086] <Operation example of control unit 4 during charging of battery B> First, when it is determined that the in-vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch, the control unit 4 controls at least one of the COM terminals of switches SW3 and SW4 to be connected to the NC terminal. In this case, the connectors CL and CN and the smoothing capacitor Cs are in an off state by switches SW3 and SW4. Further, the control unit 4 controls the operation of the bidirectional DC-DC power conversion circuit 3 to pre-charge the smoothing capacitor Cs. Note that when the smoothing capacitor Cs is pre-charged, by stopping the AC-DC power conversion circuit 2, it is possible to prevent the AC power output from the AC-DC power conversion circuit 2 from being output outside the in-vehicle power converter 1 via the in-vehicle power supply section Co.

[0087] Next, when the pre-charging of the smoothing capacitor Cs is completed, the control unit 4 controls the operation of switches SW3 and SW4 so that the COM terminals of switches SW3 and SW4 are connected to the NO terminals of switches SW3 and SW4 respectively. In this case, the connectors CL and CN and the smoothing capacitor Cs are in a conductive state by switches SW3 and SW4.

[0088] Then, the control unit 4 controls the operations of the AC-DC power conversion circuit 2 and the bidirectional DC-DC power conversion circuit 3 so that the AC power output from the external power supply device Ch is converted into the target DC power and supplied to the battery B.

[0089] <Example of the operation of the control unit 4 when supplying power to the in-vehicle power supply unit Co> First, when the control unit 4 receives a power supply instruction to the in-vehicle power supply unit Co sent from the vehicle-side control unit Cv, it controls the operations of the switches SW3 and SW4 so that the terminals COM of the switches SW3 and SW4 are connected to the terminals NC of the switches SW3 and SW4, respectively.

[0090] Then, the control unit 4 controls the operations of the AC-DC power conversion circuit 2 and the bidirectional DC-DC power conversion circuit 3 so that the DC power output from the battery B is converted into AC power and supplied to the in-vehicle power supply unit Co.

[0091] According to the in-vehicle power converter 1 of Modification 1, it has the same effects as Effects 1 to 6. Further, it has the following Effect 7.

[0092] <Effect 7> It includes an in-vehicle power supply unit Co that supplies AC power into the vehicle interior, and the AC-DC power conversion circuit 2 is a bidirectional circuit capable of AC outputting the DC power on the smoothing capacitor Cs side to the connector side. SW3 and SW4 arranged in place of the switches SW1 and SW2 are arranged between the connectors CL and CN and the AC-DC power conversion circuit 2, and connect the AC-DC power conversion circuit 2 to the connectors CL and CN, or connect the AC-DC power conversion circuit 2 to the in-vehicle power supply unit Co. Therefore, since the switches SW3 and SW4 can be used as the switches SW1 and SW2, an increase in the manufacturing cost of the in-vehicle power converter 1 having a function of supplying power to the in-vehicle power supply unit Co can be suppressed.

[0093] <Modification 2-1> FIG. 4 is a diagram showing a modification 2-1 of the in-vehicle power converter 1 according to the embodiment. In FIG. 4, the same components as those shown in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted.

[0094] In the in-vehicle power converter 1 shown in FIG. 4, the difference from the in-vehicle power converter 1 shown in FIG. 3 is that three-phase AC power output from the external power supply device Ch is converted into target DC power and supplied to the battery B. The external power supply device Ch converts the R-phase AC power among the three-phase AC power output from the AC power supply P into predetermined AC power and outputs it via the terminal R, and converts the S-phase AC power among the three-phase AC power into predetermined AC power and outputs it via the terminal S, and converts the T-phase AC power among the three-phase AC power into predetermined AC power and outputs it via the terminal T. Further, the terminal n of the external power supply device Ch is connected to the neutral point of the AC power supply P.

[0095] The in-vehicle power converter 1 shown in FIG. 4 includes connectors CR, CS, CT, and Cn instead of the connectors CL and CN, and further includes a switching circuit 5.

[0096] When the in-vehicle power converter 1 is connected to the external power supply device Ch by the charging cable Ca, the connector CR of the in-vehicle power converter 1 is connected to the terminal R of the external power supply device Ch, the connector CS of the in-vehicle power converter 1 is connected to the terminal S of the external power supply device Ch, the connector CT of the in-vehicle power converter 1 is connected to the terminal T of the external power supply device Ch, and the connector Cn of the in-vehicle power converter 1 is connected to the terminal n of the external power supply device Ch.

[0097] The AC-DC power conversion circuit 2 shown in FIG. 4 includes inductors L1 to L3 and switching elements Q13 to Q18. The switching elements Q13 to Q18 are constituted by, for example, MOSFETs.

[0098] One terminal of the inductor L1 is connected to the bus bar L31, and the other terminal of the inductor L1 is connected to the connection point between the source terminal of the switching element Q13 and the drain terminal of the switching element Q14. One terminal of the inductor L2 is connected to the bus bar L32, and the other terminal of the inductor L2 is connected to the connection point between the source terminal of the switching element Q15 and the drain terminal of the switching element Q16. One terminal of the inductor L3 is connected to the bus bar L33, and the other terminal of the inductor L3 is connected to the connection point between the source terminal of the switching element Q17 and the drain terminal of the switching element Q18.

[0099] Also, the AC-DC power conversion circuit 2 is a bidirectional circuit capable of single-phase AC output of the DC power on the smoothing capacitor Cs side to the connector CR, Cn side (refer to FIG. 4 described later for the in-vehicle power supply unit Co).

[0100] The control unit 4 controls the operation of the switching circuit 5 to switch to either a state where the power output from the external power supply device Ch can be supplied to the battery B or a state where the power output from the battery B can be supplied to the in-vehicle power supply unit Co.

[0101] FIG. 5 is a diagram showing an example of the switching circuit 5 shown in FIG. 4.

[0102] The switching circuit 5 shown in FIG. 5 includes switches SW3 to SW7, voltage sensors Sv5 to Sv10, and current sensors Si3 to Si5.

[0103] The switch SW3 is provided on the bus bar L31. Specifically, the switch SW3 has its terminal COM connected to the inductor L1, its terminal NC connected to the in-vehicle power supply unit Co, and its terminal NO connected to the connector CR. That is, the switch SW3 connects the inductor L1 to the connector CR or the in-vehicle power supply unit Co.

[0104] Switch SW4 and switch SW5 are provided on bus bar L34 that connects the connection point of switching elements Q17 and Q18 and connector Cn. Specifically, switch SW4 is composed of an electromagnetic relay with an a contact where terminal COM is connected to the connection point of switching elements Q17 and Q18, and terminal COM is connected to terminal NO of switch SW5, terminal NC is connected to in-vehicle power supply unit Co, and terminal NO is connected to connector Cn. That is, switch SW4 connects the connection point of switching elements Q17 and Q18 to connector Cn or in-vehicle power supply unit Co.

[0105] Switch SW6 is provided on bus bar L32. Specifically, switch SW6 is composed of an electromagnetic relay with a c contact, terminal COM is connected to inductor L2, terminal NC is connected to connector CR, and terminal NO is connected to connector CS. That is, switch SW6 connects inductor L2 to connector CR or connector CS.

[0106] Switch SW7 is provided on bus bar L33. Specifically, switch SW7 is composed of an electromagnetic relay with an a contact, and terminal COM is connected to inductor L3 and terminal NO is connected to connector CT.

[0107] Also, voltage sensors Sv5 to Sv7 for measuring the voltage between bus bar L31 and bus bar L34, between bus bar L32 and bus bar L34, and between bus bar L33 and bus bar L34 are provided between each of switches SW3 to SW7 and connectors CR, CS, CT, and Cn. Also, voltage sensors Sv8 to Sv10 for measuring the voltage between bus bar L31 and bus bar L34, between bus bar L32 and bus bar L34, and between bus bar L33 and bus bar L34 are provided between each of switches SW3 to SW7 and ACDC power conversion circuit 2. Also, current sensors Si3 to Si5 for measuring the current flowing through each of inductors L1, L2, and L3 are provided on bus bars L31, L32, and L33.

[0108] Note that the connection of the voltage sensors Sv5 to Sv10 is not limited to this example. Between each of the switches SW3 to SW7 and the connectors CR, CS, CT, and Cn, voltage sensors Sv5 to Sv7 for measuring the voltage between bus line L31 and bus line L32, between bus line L32 and bus line L33, and between bus line L33 and bus line L31 may be provided. Between each of the switches SW3 to SW7 and the AC-DC power conversion circuit 2, voltage sensors Sv8 to Sv10 for measuring the voltage between bus line L31 and bus line L32, between bus line L32 and bus line L33, and between bus line L33 and bus line L31 may be provided.

[0109] <Example of the operation of the control unit 4 during charging of the battery B> First, when the control unit 4 determines that the in-vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch, the control unit 4 keeps the connectors CR, CS, CT, Cn and the AC-DC power conversion circuit 2 (smoothing capacitor Cs) in a disconnected state by the switches SW3 to SW7. Here, the case where at least three of the four connectors CR, CS, CT, Cn and the bus between the AC-DC power conversion circuit 2 are turned off is defined as the disconnected state by the switches. For example, in the state of FIG. 5, although the connector CR is connected to the AC-DC power conversion circuit 2 via the terminal NC of the switch SW6 and is in an on state, the connectors CS, CT, Cn are in an off state by the switches SW4, SW5, SW6, SW7, so it is in a disconnected state. Specifically, the control unit 4 controls the operation of the switch SW3 so that the inductor L1 is connected to the in-vehicle power supply unit Co. Further, the control unit 4 controls the operations of the switches SW4 and SW5 so that the connection points of the switching elements Q17 and Q18 are not connected to the connector Cn and the in-vehicle power supply unit Co. Further, the control unit 4 controls the operation of the switch SW6 so that the inductor L2 is not connected to the connector CS. Further, the control unit 4 controls the operation of the switch SW7 so that the inductor L3 is not connected to the connector CT.

[0110] Then, the control unit 4 pre-charges the smoothing capacitor Cs by controlling the operation of the bidirectional DCDC power conversion circuit 3. When the smoothing capacitor Cs is pre-charged, by stopping the ACDC power conversion circuit 2, even if the switches SW3, SW4, and SW5 are connected to the in-vehicle power supply unit Co, it is possible to prevent the AC power output from the ACDC power conversion circuit 2 from being output to the outside of the in-vehicle power converter 1 via the in-vehicle power supply unit Co.

[0111] Next, when the pre-charging of the smoothing capacitor Cs is completed, the control unit 4 controls the operation of the switch SW3 so that the inductor L1 is connected to the connector CR, controls the operations of the switches SW4 and SW5 so that the connection point of the switching elements Q17 and Q18 is not connected to the connector Cn, controls the operation of the switch SW6 so that the inductor L2 is connected to the connector CS, and controls the operation of the switch SW7 so that the inductor L3 is connected to the connector CT. This state is set as the conduction state when three-phase AC power is input.

[0112] Then, the control unit 4 controls the operations of the ACDC power conversion circuit 2 and the bidirectional DCDC power conversion circuit 3 so that the three-phase AC power output from the external power supply device Ch is converted into the target DC power and supplied to the battery B.

[0113] Note that the in-vehicle power converter 1 in FIG. 4 can also handle the case where single-phase alternating current is input. When single-phase alternating current is input, one of the AC outputs is connected to the connector CR, and the other is connected to the connector Cn. At least one of the connectors CR and Cn and the ACDC power conversion circuit 2 (smoothing capacitor) are in an off state, which is an open state, by the switches SW3, SW4, SW5, and SW6. When the pre-charging of the smoothing capacitor Cs is completed, the control unit 4 controls the operation of the switch SW3 so that the inductor L1 is connected to the connector CR, controls the operations of the switches SW4 and SW5 so that the connection point of the switching elements Q17 and Q18 is connected to the connector Cn, and controls the operation of the switch SW6 so that the inductor L2 is connected to the connector CR. This state is a conducting state. In this connection state, an interleaved connection using the inductors L1 and L2 is achieved, and the burden on the switching elements Q13 to Q16 can be reduced. Also, the operation of the switch SW6 may be controlled so that the inductor L2 is not connected to the connector CR. This state is also a conducting state. In this connection state, the inductor L2 and the switching elements Q15 and Q16 do not function.

[0114] <Example of the operation of the control unit 4 when supplying power to the in-vehicle power supply unit Co> First, when the control unit 4 receives an instruction to supply power to the in-vehicle power supply unit Co sent from the vehicle-side control unit Cv, it controls the operation of the switch SW3 so that the inductor L1 is connected to the in-vehicle power supply unit Co, and controls the operations of the switches SW4 and SW5 so that the connection point of the switching elements Q17 and Q18 is connected to the in-vehicle power supply unit Co.

[0115] Then, the control unit 4 turns on the switching elements Q13 and Q18 and turns off the switching elements Q14, Q15, Q16, and Q17, and then repeats turning on the switching elements Q14 and Q17 and turning off the switching elements Q13, Q15, Q16, and Q18.

[0116] <Example of the operation of the control unit 4 when outputting AC power from the connector> When the control unit 4 receives an instruction from a user or the like to output the power supplied from the battery B to the outside via the connectors CR and Cn, it controls the operation of the switch SW3 so that the inductor L1 is connected to the connector CR, and controls the operations of the switches SW4 and SW5 so that the connection point of the switching elements Q17 and Q18 is connected to the connector Cn. Then, the control unit 4 turns on the switching elements Q13 and Q18 and turns off the switching elements Q14, Q15, Q16, and Q17, and then repeats turning on the switching elements Q14 and Q17 and turning off the switching elements Q13, Q15, Q16, and Q18.

[0117] Further, when the control unit 4 receives an instruction from a user or the like to output single-phase three-wire alternating current to the outside via the connectors CR, CS, and Cn for the power supplied from the battery B, it controls the operation of SW3 so that the inductor L1 is connected to the connector CR, controls the operations of the switches SW4 and SW5 so that the connection point of the switching elements Q17 and Q18 is connected to the connector Cn, and controls the switch SW6 so that the inductor L2 is connected to the connector CS. Then, the control unit alternately turns on and off the switching element Q13 and the switching element Q14, and alternately turns on and off the switching element Q15 and the switching element Q16, and repeats this to output an alternating voltage of opposite phases between the bus bars L31 and L32. Further, the control unit 4 controls the switching elements Q17 and Q18 so that the voltage value of the voltage sensor Sv5 between the bus bars L31 and L34 and the voltage value of the voltage sensor Sv6 between the bus bars L32 and L34 have opposite signs and the same magnitude.

[0118] According to the in-vehicle power converter 1 of Modification 2-1, it has the same effects as Effects 1 to 7. Further, it has the following Effect 8.

[0119] <Effect 8> It can correspond to three-phase alternating current power, and can further be applied to single-phase alternating current power. Further, it can supply single-phase three-wire alternating current.

[0120] In Modification Example 2-1, the switch SW5 may be omitted, or the switch SW6 may be an electromagnetic relay with the same a contact as the switch SW7.

[0121] <Modification Example 2-2> FIG. 6 is a diagram showing Modification Example 2-2 of the in-vehicle power converter 1 of the embodiment. In FIG. 6, the same components as those shown in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted. In the in-vehicle power converter 1 shown in FIG. 6, the connector CS is omitted as compared with the in-vehicle power converter 1 shown in FIG. 4. Further, the external power supply device Ch shown in FIG. 6 converts single-phase AC power output from a single-phase AC power supply P as an external power supply into predetermined AC power and supplies it to the in-vehicle power converter 1.

[0122] In the in-vehicle power converter 1 shown in FIG. 6, when the in-vehicle power converter 1 is connected to the external power supply device Ch via the charging cable Ca, the connector CR is connected to the output terminal OL of the external power supply device Ch via one power line in the charging cable Ca, the connector CT is connected to the output terminal ON of the external power supply device Ch via the other power line in the charging cable Ca, and the connector Cc is connected to the terminal Oc of the external power supply device Ch via the signal line in the charging cable Ca. In this state, power can be supplied from the external power supply device Ch to the in-vehicle power converter 1, and communication can be performed between the in-vehicle power converter 1 and the external power supply device Ch.

[0123] Further, the AC-DC power conversion circuit 2 shown in FIG. 6 further includes a switch SW8. The switch SW8 is composed of an electromagnetic relay with a c contact, the terminal COM is connected to the connection point of the switching elements Q17, Q18, the terminal NO is connected to the bus bar L33, and the terminal NC is connected to the bus bar L34 via the inductor L3. That is, the switch SW8 connects the connection point of the switching elements Q17, Q18 to the bus bar L33 or the bus bar L34.

[0124] FIG. 7 is a diagram showing an example of the switching circuit 5 shown in FIG. 6. In FIG. 7, the same components as those shown in FIG. 5 are denoted by the same reference numerals, and the description thereof is omitted.

[0125] In the switching circuit 5 shown in FIG. 7, a voltage sensor Sv11 for measuring the voltage between the bus bars L32 and L33 is provided between the switch SW6 and the AC-DC power conversion circuit 2. In the switching circuit 5 shown in FIG. 7, compared with the switching circuit 5 shown in FIG. 5, the switches SW3, SW4, SW7 and the voltage sensors Sv6, Sv8 to Sv10 are omitted. Further, when power is supplied from the single-phase AC power supply P to the in-vehicle power converter 1 as shown in FIG. 6, the switch SW5 may be omitted.

[0126] Also, in the switching circuit 5 shown in FIG. 7, the terminal COM of the switch SW5 is connected to the connection point of the switching elements Q17 and Q18 via the inductor L3 and the switch SW8, and the terminal NO of the switch SW5 is connected to the connector Cn. Also, in the switching circuit 5 shown in FIG. 7, the terminal COM of the switch SW6 is connected to the connection point of the switching elements Q15 and Q16 via the inductor L2, the terminal NC of the switch SW6 is connected to the connector CR, and the terminal NO of the switch SW6 is connected to the connector CT. That is, the switch SW6 connects the connection point of the switching elements Q15 and Q16 to the connector CR or the connector CT. Also, the switches SW5 and SW8 connect the connection point of the switching elements Q17 and Q18 to the connector CT or the connector Cn, or do not connect the connection point of the switching elements Q17 and Q18 to the connector CT and the connector Cn.

[0127] <Example of operation of the control unit 4 during charging of the battery B> First, when the control unit 4 determines that the in-vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch, the switches SW6 and SW8 keep the connectors CR and CT and the ACDC power conversion circuit 2 (smoothing capacitor Cs) in a disconnected state. Here, the case where the bus switch between either one of the two connectors CR and CT and the ACDC power conversion circuit 2 is turned off is regarded as the disconnected state by the switch. For example, in the state of FIG. 7, the connector CR is connected to the ACDC power conversion circuit 2 via the terminal NC of the switch SW6 and is in an on state, but the connector CT is in an off state by the switches SW6 and SW8, so it is in a disconnected state. Specifically, the control unit 4 controls the operation of the switch SW6 so that the connection point of the switching elements Q15 and Q16 is connected to the connector CR. Further, the control unit 4 controls the operation of the switch SW8 so that the connection point of the switching elements Q17 and Q18 is not connected to the connector CT. Note that the state of the switch SW5 may be either off or on.

[0128] Then, the control unit 4 controls the operation of the bidirectional DCDC power conversion circuit 3 to pre-charge the smoothing capacitor Cs. When the smoothing capacitor Cs is pre-charged, by stopping the ACDC power conversion circuit 2, even if the connection point of the switching elements Q17 and Q18 is connected to the connector CT or the connector Cn, it is possible to prevent the AC power output from the ACDC power conversion circuit 2 from being output to the outside of the in-vehicle power converter 1 via the connectors CR, CT, and Cn.

[0129] Next, when the pre-charging of the smoothing capacitor Cs is completed, the control unit 4 controls the operation of the switch SW6 so that the connection point of the switching elements Q15 and Q16 is connected to the connector CR, and controls the operation of the switch SW8 so that the connection point of the switching elements Q17 and Q18 is connected to the connector CT. This state is set as the conduction state when single-phase AC power is input.

[0130] Then, the control unit 4 controls the operations of the AC-DC power conversion circuit 2 and the bidirectional DC-DC power conversion circuit 3 so that the single-phase AC power output from the external power supply device Ch is converted into the target DC power and supplied to the battery B.

[0131] <Example of the operation of the control unit 4 when outputting AC power from the connector (during single-phase AC power supply (when the load at the power supply destination is connected to the connectors CR and CT and not connected to the connector Cn))> When the control unit 4 receives an instruction from the user or the like to convert the DC power supplied from the battery B into single-phase AC power and output it externally via the connectors CR and CT, the control unit 4 controls the operation of the switch SW6 so that the connection point of the switching elements Q15 and Q16 is connected to the connector CR, and controls the operation of the switch SW8 so that the connection point of the switching elements Q17 and Q18 is connected to the connector CT. Then, the control unit 4 turns on the switching elements Q13, Q15, and Q18 and turns off the switching elements Q14, Q16, and Q17, and then repeats turning on the switching elements Q14, Q16, and Q17 and turning off the switching elements Q13, Q15, and Q18. Note that the state of the switch SW5 may be either off or on.

[0132] <Example of the operation of the control unit 4 when outputting AC power from the connector (during single-phase three-wire AC power supply (when the load at the power supply destination is connected to the connectors CR, CT, and Cn))> When the control unit 4 receives an instruction from a user or the like to convert the DC power supplied from the battery B into single-phase three-wire AC power and output it externally via the connectors CR, CT, and Cn, it controls the operation of the switch SW6 so that the connection point of the switching elements Q15 and Q16 is connected to the connector CT, and controls the operations of the switches SW5 and SW8 so that the connection point of the switching elements Q17 and Q18 is connected to the connector Cn. Then, the control unit 4 alternately turns on and off the switching elements Q13 and Q14, and repeatedly turns on and off the switching elements Q15 and Q16 alternately to output AC voltages of opposite phases between the bus line L31 and the bus line L33. In addition, the control unit 4 controls the switching elements Q17 and Q18 so that the voltage value of the voltage sensor Sv5 between the bus line L31 and the bus line L34 and the voltage value of the voltage sensor Sv7 between the bus line L33 and the bus line L34 have opposite signs and the same magnitude.

[0133] <Example of the operation of the control unit 4 when determining the welding of the switch SW6> When AC power is output from the AC power supply P to the in-vehicle power converter 1 via the external power supply device Ch, and the control unit 4 is controlling the operation of the switch SW6 so that the terminal COM of the switch SW6 is connected to the terminal NO, the control unit 4 compares the difference ΔV between the voltage (crest value) measured by the voltage sensor Sv5 and the voltage (crest value) measured by the voltage sensor Sv7 with the voltage V11 measured by the voltage sensor Sv11. When they are equal or approximately equal to each other, it is determined that the terminals COM and NC of the switch SW6 are welded. For example, when the control unit 4 is controlling the operation of the switch SW6 so that the terminal COM of the switch SW6 is connected to the terminal NO, if the difference between the difference ΔV and the voltage V11 is equal to or less than the voltage threshold value Vth3, it is determined that the terminals COM and NC of the switch SW6 are welded.

[0134] According to the in-vehicle power converter 1 of Modification 2-2, it has the same effects as Effects 1 to 5 and Effect 8, and also has the following Effect 9.

[0135] <Effect 9> The in-vehicle power converter 1 includes a switch SW6 and voltage sensors Sv5, Sv7, and Sv11. Therefore, when AC power is output from the AC power source P to the in-vehicle power converter 1 via the external power supply device Ch, the control unit 4 controls the operation of the switch SW6 so that the terminal COM of the switch SW6 is connected to the terminal NO. When comparing the difference ΔV and the voltage V11 and determining that they are equal or substantially equal to each other, it is determined that the terminals COM and NC of the switch SW6 are welded. Thereby, it is possible to determine whether the switch SW6 is welded or not.

[0136] <Modification Example 2-3> FIG. 8 is a diagram showing Modification Example 2-3 of the in-vehicle power converter 1 of the embodiment. In FIG. 8, the same components as those shown in FIG. 6 are denoted by the same reference numerals, and the description thereof is omitted. The switching circuit 5 shown in FIG. 8 is the same as, for example, the switching circuit 5 shown in FIG. 7. In the in-vehicle power converter 1 shown in FIG. 8, when connected to the external power supply device Ch via the charging cable Ca, the connector Cn of the in-vehicle power converter 1 is connected to the terminal n of the external power supply device Ch via the power line in the charging cable Ca. The neutral point is connected to the ground and also connected to the terminal n of the external power supply device Ch.

[0137] The external power supply device Ch shown in FIG. 8 converts single-phase three-wire AC power output from the AC power source P as an external power supply into predetermined AC power and supplies it to the in-vehicle power converter 1.

[0138] <Operation Example of Control Unit 4 During Charging of Battery B> First, when the control unit 4 determines that the in-vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch, the switches SW5, SW6, and SW8 keep the connectors CR, CT, Cn and the ACDC power conversion circuit 2 (smoothing capacitor Cs) in a disconnected state. Here, the case where the bus switches between at least two of the three connectors CR, CT, Cn and the ACDC power conversion circuit 2 are turned off is regarded as the disconnected state by the switches. For example, the control unit 4 controls the operation of the switch SW6 so that the connection point of the switching elements Q15, Q16 is connected to the connector CR. Further, the control unit 4 controls the operations of the switches SW5 and SW8 so that the connection points of the switching elements Q17, Q18 are not connected to the connectors CT, Cn.

[0139] Then, the control unit 4 controls the operation of the bidirectional DCDC power conversion circuit 3 to pre-charge the smoothing capacitor Cs. When the smoothing capacitor Cs is pre-charged, by stopping the ACDC power conversion circuit 2, even if the connection points of the switching elements Q17, Q18 are connected to the connector CT or the connector Cn, it is possible to prevent the AC power output from the ACDC power conversion circuit 2 from being output to the outside of the in-vehicle power converter 1 via the connectors CR, CT, Cn.

[0140] Next, when the pre-charging of the smoothing capacitor Cs is completed, the control unit 4 controls the operation of the switch SW6 so that the connection point of the switching elements Q15, Q16 is connected to the connector CR, and controls the operation of the switch SW8 so that the connection point of the switching elements Q17, Q18 is connected to the connector CT. This state is set as the conduction state when single-phase three-wire AC power is input.

[0141] Then, the control unit 4 controls the operations of the ACDC power conversion circuit 2 and the bidirectional DCDC power conversion circuit 3 so that the single-phase three-wire AC power output from the external power supply device Ch is converted into the target DC power and supplied to the battery B.

[0142] In Modification 2-3, the operation example of the control unit 4 when outputting AC power (single-phase AC power or single-phase three-wire AC power) from the connector is the same as the operation example of the control unit 4 when outputting AC power from the connector in Modification 2-2. Therefore, the description thereof is omitted.

[0143] Also, the welding check of the switch SW6 in Modification 2-3 is the same as the welding check of the switch SW6 in Modification 2-2. Therefore, the description thereof is omitted.

[0144] According to the in-vehicle power converter 1 of Modification 2-3, it has the same effects as Effects 1 to 5, Effect 8, and Effect 9.

[0145] <Modification 2-4> FIG. 9 is a diagram showing Modification 2-4 of the in-vehicle power converter 1 of the embodiment. In FIG. 9, the same components as those shown in FIG. 6 are denoted by the same reference numerals, and the description thereof is omitted. Also, the switching circuit 5 shown in FIG. 9 is, for example, the same as the switching circuit 5 shown in FIG. 7. Further, in the in-vehicle power converter 1 shown in FIG. 9, when connected to the external power supply device Ch via the charging cable Ca, the connector CR of the in-vehicle power converter 1 is connected to the terminal R of the external power supply device Ch via the power line in the charging cable Ca, the connector CT of the in-vehicle power converter 1 is connected to the terminal S of the external power supply device Ch via the power line in the charging cable Ca, the connector Cn of the in-vehicle power converter 1 is connected to the terminal T of the external power supply device Ch via the power line in the charging cable Ca, and the connector Cc of the in-vehicle power converter 1 is connected to the terminal Oc of the external power supply device Ch via the signal line in the charging cable Ca.

[0146] The external power supply device Ch shown in FIG. 9 converts the three-phase AC power output from the AC power supply P as an external power supply into a predetermined AC power and supplies it to the in-vehicle power converter 1.

[0147] <Operation example of the control unit 4 during charging of the battery B> First, when the control unit 4 determines that the in-vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch, the switches SW5, SW6, and SW8 keep the connectors CR, CT, and Cn and the ACDC power conversion circuit 2 (smoothing capacitor Cs) in a disconnected state. Here, the case where the bus switches between at least two of the three connectors CR, CT, and Cn and the ACDC power conversion circuit 2 are in the off state is regarded as the disconnected state by the switches. For example, the control unit 4 controls the operation of the switch SW6 so that the connection point of the switching elements Q15 and Q16 is connected to the connector CR. Also, the control unit 4 controls the operations of the switches SW5 and SW8 so that the connection points of the switching elements Q17 and Q18 are not connected to the connectors CT and Cn.

[0148] Then, the control unit 4 controls the operation of the bidirectional DCDC power conversion circuit 3 to pre-charge the smoothing capacitor Cs. When the smoothing capacitor Cs is pre-charged, by stopping the ACDC power conversion circuit 2, even if the connection points of the switching elements Q17 and Q18 are connected to the connector CT or the connector Cn, it is possible to prevent the AC power output from the ACDC power conversion circuit 2 from being output to the outside of the in-vehicle power converter 1 via the connectors CR, CT, and Cn.

[0149] Next, when the pre-charging of the smoothing capacitor Cs is completed, the control unit 4 controls the operation of the switch SW6 so that the connection point of the switching elements Q15 and Q16 is connected to the connector CT, and controls the operations of the switches SW5 and SW8 so that the connection points of the switching elements Q17 and Q18 are connected to the connector Cn. This state is set as the conduction state when three-phase AC power is input.

[0150] Then, the control unit 4 controls the operations of the ACDC power conversion circuit 2 and the bidirectional DCDC power conversion circuit 3 so that the three-phase AC power output from the external power supply device Ch is converted into the target DC power and supplied to the battery B.

[0151] In Modification 2-4, the operation example of the control unit 4 when outputting AC power (single-phase AC power or single-phase three-wire AC power) from the connector is the same as the operation example of the control unit 4 when outputting AC power from the connector in Modification 2-2. Therefore, the description thereof is omitted.

[0152] Also, the welding check of the switch SW6 in Modification 2-4 is the same as the welding check of the switch SW6 in Modification 2-2. Therefore, the description thereof is omitted.

[0153] According to the in-vehicle power converter 1 of Modification 2-4, it has the same effects as Effects 1 to 5, Effect 8, and Effect 9.

[0154] <Modification 3> FIG. 10 is a diagram showing Modification 3 of the in-vehicle power converter 1 of the embodiment. In FIG. 10, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

[0155] In the in - vehicle power converter 1 shown in Fig. 10, the differences from the in - vehicle power converter 1 shown in Fig. 1 are as follows: A bus bar L11 is provided between the switch SW1 and the AC - DC power conversion circuit 2, and a noise - reducing capacitor Cy1 as a capacitor is provided between the bus bar L11 and the ground. Also, a bus bar L12 is provided between the switch SW2 and the AC - DC power conversion circuit 2, and a capacitor Cy2 as a noise - reducing capacitor is provided between the bus bar L12 and the ground. That is, switches (switches SW1 and SW2) are provided on all of the bus bars L11 and L12 to which the noise - reducing capacitors Cy1 and Cy2 are connected. Note that two AC power supplies P with a phase difference of 180 degrees are connected, the neutral point is connected to the ground, and both ends are connected to the external power supply device Ch. That is, both ends of a single - phase three - wire AC are connected to the external power supply device Ch. Also, when the switches SW1 and SW2 are in the off state, it is assumed that the bus bars L11 and L12 between the connectors CL, CN and the capacitors Cy1, Cy2 are disconnected. Also, the noise - reducing capacitors may be provided between the bus bars L31, L32, L33, L34 between the switching circuit 5 and the AC - DC power conversion circuit 2 and the ground in the in - vehicle power converter 1 shown in Figs. 4 and 8.

[0156] The control unit 4 shown in Fig. 10, similar to the control unit 4 shown in Fig. 1, keeps the connectors CL, CN and the smoothing capacitor Cs in a disconnected state by the switches SW1 and SW2 from the end of the previous charging of the battery B until the pre - charging of the smoothing capacitor Cs is completed. In particular, in Modification 3, by turning off both switches SW1 and SW2, both bus bars L11 and L12 are made non - connected to put them in a disconnected state.

[0157] According to the in - vehicle power converter 1 of Modification 3, it has the same effects as Effects 1 - 6. Also, it has the following Effect 10.

[0158] <Effect 10> Switches SW1 and SW2 are arranged between connectors CL and CN and the ACDC power conversion circuit 2. Noise reduction capacitors Cy1 and Cy2 are provided between the switches SW1 and SW2 and the ground via buses L11 and L12 provided between the switches SW1 and SW2 and the ACDC power conversion circuit 2. Switches (switches SW1 and SW2) are arranged on all of the buses L11 and L12 to which the noise reduction capacitors Cy1 and Cy2 are connected. Therefore, it is possible to turn off all of the buses provided with the noise reduction capacitors.

[0159] When the AC power supply P is connected to the ground and only one of the switches SW1 and SW2, for example, when switch SW2 is absent, even in the off state with switch SW1 turned off, a loop is formed in the order of bus L12, capacitor Cy2, ground, AC power supply P, external power supply device Ch, and bus L12, and reactive current is generated. However, in Modification 3, since switches SW1 and SW2 can be turned off for both of the buses L11 and L12 provided with the noise reduction capacitors, generation of reactive current can be suppressed. Even if there is one AC power supply P as in FIG. 1 or one terminal of the AC power supply P is connected to the ground, the same problem occurs. Therefore, according to the in-vehicle power converter 1 of Modification 3, there is an effect of suppressing reactive power.

[0160] <Modification 4> FIG. 11 is a diagram showing Modification 4 of the in-vehicle power converter 1 of the embodiment. In FIG. 11, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

[0161] In the in-vehicle power converter 1 shown in FIG. 11, the switches SW1 and SW2 are located between the connectors CL and CN and the smoothing capacitor Cs. In this embodiment, they are provided on the bus bars L21 and L22 between the AC-DC power conversion circuit 2 and the smoothing capacitor Cs. As another point different from the in-vehicle power converter 1 shown in FIG. 1, a voltage sensor Sv2 (second voltage sensor) is provided on the bus bars L21 and L22 between the switches SW1 and SW2 and the bidirectional DC-DC power conversion circuit 3. Note that a voltage sensor Sv3 (first voltage sensor) is provided between the switches SW1 and SW2 and the AC-DC power conversion circuit 2.

[0162] When it is determined that the in-vehicle power converter 1 is connected to the AC power supply P via the external power supply device Ch as shown in FIG. 11, the control unit 4 shown in FIG. 11 controls the operation of the bidirectional DC-DC power conversion circuit 3 while keeping the connectors CL and CN and the smoothing capacitor Cs in a disconnected state by the switches SW1 and SW2, thereby supplying the power output from the battery B to the smoothing capacitor Cs and pre-charging the smoothing capacitor Cs.

[0163] Also, when AC power is being output from the external power supply device Ch to the in-vehicle power converter 1 as shown in FIG. 11, and when the voltage V3 detected by the voltage sensor Sv3 is equal to or higher than the voltage threshold Vth1 (first voltage threshold) and the voltage V2 detected by the voltage sensor Sv2 is equal to or higher than the voltage threshold Vth2 (second voltage threshold) while the connectors CL and CN and the smoothing capacitor Cs are kept in a disconnected state by the switches SW1 and SW2, the control unit 4 shown in FIG. 11 determines that the switches SW1 and SW2 are welded. Thereby, it is possible to determine whether or not the switches SW1 and SW2 are welded.

[0164] Further, when AC power is output from the AC power supply P to the in-vehicle power converter 1 via the external power supply device Ch, the control unit 4 shown in FIG. 11 may be configured to change a predetermined time t (voltage threshold, current threshold, threshold of a predetermined current integration amount) according to the voltage V1 detected by the voltage sensor Sv1 when the connectors CL, CN and the smoothing capacitor Cs are kept in a disconnected state by the switches SW1, SW2. For example, specifically, the lower the voltage V1 is, the shorter the predetermined time t may be configured. Thereby, the time taken from when the in-vehicle power converter 1 is electrically connected to the external power supply device Ch until the charging of the battery B is started can be shortened. Also, instead of the voltage V1, the voltage V3 detected by the voltage sensor Sv3 may be used.

[0165] According to the in-vehicle power converter 1 of Modification 4, it has the same effects as Effects 1 to 5. Also, it has the following Effect 11.

[0166] <Effect 11> The in-vehicle power converter 1 includes switches SW1, SW2, a voltage sensor Sv3, and a voltage sensor Sv2. Therefore, when AC power is output from the AC power supply P to the in-vehicle power converter 1 via the external power supply device Ch, when the connectors CL, CN and the smoothing capacitor Cs are kept in a disconnected state by the switches SW1, SW2, if the voltage V3 detected by the voltage sensor Sv3 is equal to or higher than a voltage threshold Vth1 (first voltage threshold), and if the voltage V2 detected by the voltage sensor Sv2 is equal to or higher than a voltage threshold Vth2 (second voltage threshold), it is determined that the switches SW1, SW2 are welded. Thereby, it is possible to determine whether or not the switches SW1, SW2 are welded.

[0167] <Modification 5> FIG. 12 is a diagram showing a fifth modification of the in-vehicle power converter 1 according to the embodiment. In FIG. 12, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. In the present embodiment, the voltage sensor Sv1 is an analog sensor, and by detecting the frequency of the voltage V1 which is the detected value thereof, the control unit 4 can determine whether the voltages input to the buses L11 and L12 are AC voltages or DC voltages. Also, the connectors CL, CN, and Cc are structured such that both an AC connector and a DC connector can be connected. Further, although FIG. 12 shows a state in which the in-vehicle power converter 1 is connected to the external power supply device Ch of the AC power supply P, the connector shape is such that it can also be connected to the external power supply device of the DC power supply, and the state of being connected to the external power supply device of the DC power supply will also be described.

[0168] The in-vehicle power converter 1 shown in FIG. 12 further includes switches SW9 and SW10. The switches SW9 and SW10 are constituted by, for example, electromagnetic relays of a contacts. One terminal of the switch SW9 is connected to the connector CL, and the other terminal of the switch SW9 is connected to the positive terminal of the battery B. One terminal of the switch SW10 is connected to the connector CN, and the other terminal of the switch SW10 is connected to the negative terminal of the battery B. That is, the switches SW9 and SW10 function as bypass switches for connecting the connectors CL and CN and the battery B by bypassing the AC-DC power conversion circuit 2 and the bidirectional DC-DC power conversion circuit 3.

[0169] When the control unit 4 shown in FIG. 12 determines that the power source is AC based on the voltage V1 detected by the voltage sensor Sv1, it determines that the in-vehicle power converter 1 is connected to the AC power source P via the external power supply device Ch. That is, it corresponds to the case where the power input to the connectors CL and CN is AC. In this case, a battery charging preparation operation is executed. With at least one of the switches SW1 and SW2 in the off state to keep the connectors CL and CN and the smoothing capacitor Cs in a disconnected state, the smoothing capacitor Cs is pre-charged. At this time, at least one of the switches SW9 and SW10 is maintained in the off state. After supplying power from the battery B to the smoothing capacitor Cs, next, both the switches SW1 and SW2 are switched to the on state to transition to the conductive state, and while maintaining the switches SW9 and SW10 in the off state, the operations of the AC-DC power conversion circuit 2 and the bidirectional DC-DC power conversion circuit 3 are controlled so that the battery B is charged by the AC power supplied from the external power supply device Ch.

[0170] Next, the case where the in-vehicle power converter 1 is connected to an external power supply device of a DC power source will be described. When the control unit 4 determines that the power source is DC based on the voltage V1 detected by the voltage sensor Sv1, it determines that the in-vehicle power converter 1 is connected to a DC power source (not shown) via the external power supply device Ch. That is, it corresponds to the case where the power input to the connectors CL and CN is DC. In this case, the battery charging operation is not executed, the connectors CL and CN and the smoothing capacitor Cs are kept in the disconnected state by the switches SW1 and SW2, and the switches SW9 and SW10 are switched from the off state to the on state, and the battery B is charged by supplying the DC power supplied from the external power supply device Ch to the battery B via the switches SW9 and SW10.

[0171] Note that the control unit 4 shown in FIG. 12 may determine whether the power input to the connectors CL and CN is AC or DC by performing wired communication with the external power supply device Ch using the signal lines and the signal line Lc in the charging cable Ca, or by performing wireless communication with the external power supply device Ch. Further, it may be determined whether the power input to the connectors CL and CN by a signal from the vehicle-side control unit Cv is AC power or DC power. Also, a DC voltage sensor and an AC voltage sensor may be provided as the voltage sensor Sv1, respectively.

[0172] Further, in the in-vehicle power converter 1 shown in FIG. 12, like the in-vehicle power converter 1 shown in FIG. 11, the switches SW1 and SW2 may be provided on the buses L21 and L22 between the AC-DC power conversion circuit 2 and the smoothing capacitor Cs.

[0173] Further, when AC power is output from the external power supply device Ch to the in-vehicle power converter 1 shown in FIG. 12, when the switches SW1, SW2, SW9, and SW10 keep the connectors CL and CN and the smoothing capacitor Cs in a disconnected state, if the voltage V1 detected by the voltage sensor Sv1 is equal to or higher than the voltage threshold Vth1 (first voltage threshold), and if the voltage V2 detected by the voltage sensor Sv2 is equal to or higher than the voltage threshold Vth2 (second voltage threshold), it may be determined that the switches SW1 and SW2 are welded. Thereby, it is possible to determine whether the switches SW1 and SW2 are welded. Also, by using the voltage V4 detected by the voltage sensor Sv4, it is also possible to determine whether the switches SW9 and SW10 are welded.

[0174] Also, when AC power is output from the AC power supply P to the in-vehicle power converter 1 via the external power supply device Ch, the control unit 4 shown in FIG. 12 may be configured to change a predetermined time t (voltage threshold, current threshold, threshold of a predetermined current integration amount) according to the voltage V1 detected by the voltage sensor Sv1 when the switches SW1, SW2, SW9, and SW10 keep the connectors CL, CN and the smoothing capacitor Cs in a disconnected state. For example, specifically, the lower the voltage V1, the shorter the predetermined time t may be configured. Thereby, the time taken from when the in-vehicle power converter 1 is electrically connected to the external power supply device Ch until the charging of the battery B starts can be shortened.

[0175] According to the in-vehicle power converter 1 of Modification 5, it has the same effects as Effects 1 to 6. Also, it has the following Effect 12.

[0176] <Effect 12> When the power input to the connectors CL, CN is AC, the control unit 4 executes a battery charging preparation operation. When the power input to the connectors CL, CN is DC, the control unit 4 does not execute the battery charging preparation operation and keeps the switches SW1, SW2 to keep the connectors CL, CN and the smoothing capacitor Cs in a disconnected state. Therefore, even when DC is input, the ACDC power conversion circuit 2 or the smoothing capacitor Cs is blocked, so there is no problem even when DC is input. That is, since it is not necessary to provide a dedicated connector for inputting DC power supplied from the external power supply device Ch separately from the connectors CL, CN, the manufacturing cost of the in-vehicle power converter 1 can be suppressed from increasing accordingly. Also, when the power supplied from the external power supply device Ch is DC power, it is not necessary to pre-charge the smoothing capacitor Cs, so the unnecessary battery charging preparation operation can be omitted.

[0177] Note that the present invention is not limited to the above embodiments, and various improvements and changes are possible without departing from the gist of the present invention.

[0178] It may be directly connected to the AC power supply P or a DC power supply even without passing through the external power supply device Ch, as in Modification 5.

[0179] The terminals NO and NC of the electromagnetic relay of the c contact may be reversed. The electromagnetic relay of the a contact may be replaced with the electromagnetic relay of the b contact. However, when no control signal is applied to each switch, it is connected to the terminal NC. If this state is not an open state, it is necessary to switch to the terminal NO side in advance and set it to the open state at a stage before it is determined that the in-vehicle power converter 1 is connected to an external power source. Control signals from the control unit 4 may be input to each switch as required.

[0180] When there is no need to output AC power from the battery B to the connector or the in-vehicle power supply unit Co in the vehicle interior, the circuit configuration of the ACDC power conversion circuit 2 is not limited to the circuit configurations shown in Fig. 2(a), Fig. 4, or Fig. 6, as long as it is at least a circuit configuration capable of rectifying the input AC power. For example, the ACDC power conversion circuit 2 may be provided with a diode rectifier circuit on the connector side, connect the positive output of the diode rectifier circuit to one terminal of the inductor L, connect the negative output to the source terminal of the switching element Q2, omit the phase having the switching elements Q3 and Q4, and use only the phase having the switching elements Q1 and Q2. Also, if power factor improvement is not required, the ACDC power conversion circuit 2 may be composed of a simple diode rectifier circuit.

[0181] When corresponding to three-phase AC as in Modification 2-1 and the connector Cn is omitted, turning off the switch for the bus between two of the three connectors CR, CS, and CT and the ACDC power conversion circuit 2 may be regarded as the open state.

[0182] In Modification 2-1, the switch SW5 may be omitted, or the in-vehicle power supply unit Co may be omitted, and the switches SW3 and SW4 may be electromagnetic relays of the a contact or the b contact.

[0183] In Modification 3 and Modification 5, like Modification 1, the switches SW1 and SW2 may be replaced with the switches SW3 and SW4, and the in-vehicle power supply unit Co may be provided.

[0184] The noise reduction capacitor as in Modification 3 may be applied to the three-phase AC circuit as in Modification 2-1 or the single-phase three-wire AC circuit as in Modification 2-3.

[0185] In Modification 5, the bypass path that connects the connector CL, CN and the battery B by bypassing the AC-DC power conversion circuit 2 and the bidirectional DC-DC power conversion circuit 3 via the switches SW9 and SW10 is provided inside the in-vehicle power converter 1, but it may also be provided outside the in-vehicle power converter 1. Further, a desired power converter, relay, capacitor, etc. may be provided in the path.

[0186] When AC is input to the connector in Modification 5, and when DC is input, the control may be applied to Modification 2-1 or Modification 2-4 corresponding to three-phase AC.

[0187] Hereinafter, the characteristic points of the above-described embodiments will be organized.

[0188] (Appendix 1) An in-vehicle power converter mounted on a vehicle, a connector to which power output from an external power source is input, an AC-DC power conversion circuit that rectifies the AC power input to the connector, a smoothing capacitor that smooths the power rectified by the AC-DC power conversion circuit, a bidirectional DC-DC power conversion circuit that converts the DC power smoothed by the smoothing capacitor into a target DC power and supplies it to a battery mounted on the vehicle, a switch provided between the connector and the smoothing capacitor, a control unit that controls the operations of the AC-DC power conversion circuit, the bidirectional DC-DC power conversion circuit, and the switch, comprising When it is determined that the in-vehicle power converter is connected to the external power source, the control unit executes a battery charging preparation operation. The battery charging preparation operation controls the operation of the bidirectional DCDC power conversion circuit while keeping the switch in a state of blocking the connector and the smoothing capacitor, so as to supply the power output from the battery to the smoothing capacitor, and then transitions the switch from the blocking state to the conducting state. In - vehicle power converter.

[0189] (Appendix 2) The in - vehicle power converter according to Appendix 1, In the battery charging preparation operation, when a predetermined time has elapsed since the start of power supply from the battery to the smoothing capacitor, the control unit transitions the switch from the blocking state to the conducting state. The predetermined time is not less than the time when the voltage value of the smoothing capacitor reaches a voltage value such that the current value flowing from the ACDC power conversion circuit when the switch transitions to the conducting state is less than or equal to the allowable current value of the smoothing capacitor, and is not more than the time when the voltage value of the smoothing capacitor reaches a voltage value equal to the peak value of the AC power input from the external power source or the voltage value of the DC power supplied from the ACDC power conversion circuit. In - vehicle power converter.

[0190] (Appendix 3) The in - vehicle power converter according to Appendix 1 or Appendix 2, Comprises an in - vehicle power supply unit for supplying AC power into the vehicle interior. The ACDC power conversion circuit is a bidirectional circuit capable of AC - outputting the DC power on the smoothing capacitor side to the connector side. The switch is arranged between the connector and the ACDC power conversion circuit, and connects the ACDC power conversion circuit to the connector or connects the ACDC power conversion circuit to the in - vehicle power supply unit. In - vehicle power converter.

[0191] (Appendix 4) The in - vehicle power converter according to any one of Appendices 1 to 3, The switch provided between the connector and the AC-DC power conversion circuit, and the first voltage sensor provided between the switch and the connector, the second voltage sensor provided between the switch and the AC-DC power conversion circuit, and are provided with, when the switch cuts off the connector and the smoothing capacitor, the control unit determines that the switch is welded when the first voltage detected by the first voltage sensor is equal to or higher than a first voltage threshold value and the second voltage detected by the second voltage sensor is equal to or higher than a second voltage threshold value. In-vehicle power converter.

[0192] (Appendix 5) The in-vehicle power converter according to any one of Appendices 1 to 3, the switch provided between the AC-DC power conversion circuit and the smoothing capacitor, the first voltage sensor provided between the AC-DC power conversion circuit, the second voltage sensor provided between the switch and the bidirectional DC-DC power conversion circuit, and are provided with, when the switch cuts off the connector and the smoothing capacitor, the control unit determines that the switch is welded when the first voltage detected by the first voltage sensor is equal to or higher than a first voltage threshold value and the second voltage detected by the second voltage sensor is equal to or higher than a second voltage threshold value. In-vehicle power converter.

[0193] (Appendix 6) The in-vehicle power converter according to Appendix 2, is provided with a voltage sensor provided between the connector and the switch, the control unit shortens the predetermined time as the voltage detected by the voltage sensor is lower. In-vehicle power converter.

[0194] (Appendix 7) The in-vehicle power converter according to any one of Appendices 1 to 6, The switch is arranged between the connector and the AC-DC power conversion circuit, and includes a capacitor provided between a bus provided between the switch and the AC-DC power conversion circuit and the ground, and the switch is arranged on all buses to which the capacitor is connected. In-vehicle power converter.

[0195] (Appendix 8) An in-vehicle power converter according to any one of Appendices 1 to 7, wherein when the power input to the connector is AC, the control unit executes the battery charging preparation operation, and when the power input to the connector is DC, the control unit does not execute the battery charging preparation operation and keeps the switch in an off state. In-vehicle power converter.

Description of Reference Numerals

[0196] 1 In-vehicle power converter 2 AC-DC power conversion circuit 3 Bidirectional DC-DC power conversion circuit 4 Control unit P AC power supply as an external power source Ch External power supply device OL, ON Output terminals Ca Charging cable CL, CN, CR, CS, CT, Cn, Cc Connectors Si1, Si5 Current sensors Sv1~Sv11 Voltage sensors SW1~SW10 Switches Cs Smoothing capacitor B Battery C, Cy1, Cy2 Capacitors L, L1~L3 Inductors Q1~Q18 Switching elements Tr Transformer Co In-vehicle power supply unit

Claims

1. An in-vehicle power converter mounted on a vehicle, a connector to which power output from an external power source is input, an AC-DC power conversion circuit that rectifies the AC power input to the connector, a smoothing capacitor that smooths the power rectified by the AC-DC power conversion circuit, a bidirectional DC-DC power conversion circuit that converts the DC power smoothed by the smoothing capacitor into target DC power and supplies it to a battery mounted on the vehicle, a switch provided between the connector and the smoothing capacitor, a control unit that controls the operations of the AC-DC power conversion circuit, the bidirectional DC-DC power conversion circuit, and the switch, comprising When it is determined that the in-vehicle power converter is connected to the external power source, the control unit executes a battery charging preparation operation, The battery charging preparation operation is to supply the power output from the battery to the smoothing capacitor by controlling the operation of the bidirectional DC-DC power conversion circuit while keeping the connector and the smoothing capacitor in a disconnected state by the switch, and then transition the switch from the disconnected state to the conducting state In-vehicle power converter.

2. The in-vehicle power converter according to claim 1, In the battery charging preparation operation, when a predetermined time has elapsed since the power supply from the battery to the smoothing capacitor was started, the control unit transitions the switch from the disconnected state to the conducting state, The predetermined time is equal to or longer than the time when the voltage value of the smoothing capacitor reaches a voltage value such that the current value flowing from the AC-DC power conversion circuit when the switch is transitioned to the conducting state is equal to or less than the allowable current value of the smoothing capacitor, and is equal to or shorter than the time when the voltage value reaches a voltage value equal to the peak value of the AC power input from the external power source or the voltage value of the DC power supplied from the AC-DC power conversion circuit In-vehicle power converter.

3. The in-vehicle power converter according to claim 1, comprising: an in-vehicle power supply unit that supplies AC power into the vehicle cabin; the AC-DC power conversion circuit is a bidirectional circuit capable of AC outputting the DC power on the smoothing capacitor side to the connector side; the switch is disposed between the connector and the AC-DC power conversion circuit, and connects the AC-DC power conversion circuit to the connector, or connects the AC-DC power conversion circuit to the in-vehicle power supply unit an in-vehicle power converter.

4. The in-vehicle power converter according to claim 1, comprising: the switch provided between the connector and the AC-DC power conversion circuit, a first voltage sensor provided between the switch and the connector, a second voltage sensor provided between the switch and the AC-DC power conversion circuit, and when the control unit turns off the connector and the smoothing capacitor by the switch, if the first voltage detected by the first voltage sensor is equal to or higher than a first voltage threshold value, and the second voltage detected by the second voltage sensor is equal to or higher than a second voltage threshold value, it is determined that the switch is welded an in-vehicle power converter.

5. The in-vehicle power converter according to claim 1, comprising: the switch provided between the AC-DC power conversion circuit and the smoothing capacitor, a first voltage sensor provided between the AC-DC power conversion circuit and the switch, a second voltage sensor provided between the switch and the bidirectional DC-DC power conversion circuit, and are provided. When the control unit turns off the connector and the smoothing capacitor by the switch, if the first voltage detected by the first voltage sensor is equal to or higher than the first voltage threshold value, and if the second voltage detected by the second voltage sensor is equal to or higher than the second voltage threshold value, it is determined that the switch is welded. In - vehicle power converter.

6. The in - vehicle power converter according to claim 2, comprising a voltage sensor provided between the connector and the switch, The control unit shortens the predetermined time as the voltage detected by the voltage sensor is lower. In - vehicle power converter.

7. The in - vehicle power converter according to claim 1, The switch is arranged between the connector and the AC - DC power conversion circuit, comprising a capacitor provided between a bus provided between the switch and the AC - DC power conversion circuit and the ground, The switch is arranged on all buses to which the capacitor is connected. In - vehicle power converter.

8. The in - vehicle power converter according to claim 1, When the power input to the connector is AC, the control unit executes the battery charging preparation operation. When the power input to the connector is DC, the control unit does not execute the battery charging preparation operation and keeps the switch in the off state. In - vehicle power converter.

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