Power supply device

Abstract

To provide a power supply device that can perform charging even if the voltage on a storage battery side is high.SOLUTION: A power supply device comprises: a storage battery; a capacitor part in which a first capacitor and a second capacitor are connected in series between a positive electrode side terminal and a negative electrode side terminal of the storage battery; a power converter in which a three-level inverter is connected in series with the storage battery; a control unit that controls switching of turn-on and turn-off of switching elements; a first connection terminal that is connected with a P-terminal of a DC charger between a first switching element and a second switching element in any one phase of three phases; and a second connection terminal that is connected with an N-terminal of the DC charger between a third switching element and a fourth switching element in another one phase. The control unit controls the switching of turn-on and turn-off of the switching elements to alternately switch between a first mode in which the first capacitor is charged, a second mode in which the second capacitor is charged, and a third mode in which the first capacitor and the second capacitor are charged.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a power supply device. [Background technology]

[0002] Patent Document 1 discloses a configuration in which an inverter for driving a motor generator also functions as a charger. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-252074 A Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed in Patent Document 1 assumes AC charging, and does not consider DC charging at all. On the other hand, existing DC chargers have maximum voltages of 400 [V] and 800 [V], so it is preferable for the vehicle side to be compatible with both voltages. However, if the battery voltage on the vehicle side is higher than the maximum voltage of the charger, charging is not possible. Although it is possible to address this by connecting the batteries in parallel, this increases the charging time, leaving room for improvement.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a power supply device that is capable of charging even when the voltage on the storage battery side is high. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, a power supply device according to the present invention includes a storage battery, a capacitor unit in which a first capacitor and a second capacitor are connected in series between a positive terminal and a negative terminal of the storage battery, a first switching element, a second switching element, a third switching element, and a fourth switching element connected in series, a first diode having a cathode connected to a wiring connecting the first switching element and the second switching element and an anode connected to a wiring connecting the first capacitor and the second capacitor, and a second diode having an anode connected to a wiring connecting the third switching element and the fourth switching element and a cathode connected to a wiring connecting the first capacitor and the second capacitor, and the power supply device selectively supplies a voltage of one of three different voltage values ​​to a motor by switching on and off each of the first switching element, the second switching element, the third switching element, and the fourth switching element. a control device for controlling the switching on and off of each switching element of the power converter; a first connection terminal electrically connected to a P terminal of a DC charger between the first switching element and the second switching element of the three-level inverter for any one of the U phase, the V phase, and the W phase; and a second connection terminal electrically connected to an N terminal of the DC charger between the third switching element and the fourth switching element of the three-level inverter for the other one of the U phase, the V phase, and the W phase, wherein the control device controls the switching on and off of each switching element to alternate between a first mode in which the first capacitor is charged, a second mode in which the second capacitor is charged, and a third mode in which the first capacitor and the second capacitor are charged. Effect of the Invention

[0007] The power supply device according to the present invention can obtain an arbitrary step-up ratio for the voltage on the charger side, and therefore has the effect of making it possible to charge even if the voltage on the storage battery side is high. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a configuration diagram of a power system according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing the configuration of the power system according to the embodiment. [Diagram 3] FIG. 3 is a diagram showing the circuit state when the battery is charged by a DC charger in the direct connection mode. [Figure 4] FIG. 4 is a diagram showing a circuit state in a first charging mode when the battery is charged by a DC charger in the boost mode. [Diagram 5] FIG. 5 is a diagram showing the circuit state in the second charging mode when the battery is charged by the DC charger in the boost mode. [Figure 6] FIG. 6 is a diagram showing the circuit state in the third charging mode when the battery is charged by the DC charger in the boost mode. [Figure 7] FIG. 7 is a graph showing waveforms of the voltages, currents, and on / off states of the switching elements over time in the boost mode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a power supply device according to the present invention will be described. Note that the present invention is not limited to the embodiment.

[0010] 1 is a configuration diagram of a power system according to an embodiment. The power system according to the embodiment is applied to electric vehicles that can run on electricity, such as electric vehicles, hybrid vehicles, plug-in hybrid vehicles (PHVs), and range extended electric vehicles (REEVs).

[0011] The power system according to the embodiment is composed of a power supply device 10, a motor generator 20, a DC charger 30, etc. In the power system according to the embodiment, the power supply device 10 and the motor generator 20 are mounted on the electric vehicle, and the DC charger 30 is provided in an external charging facility or the like installed outside the electric vehicle.

[0012] The power supply device 10 includes a battery 12, a capacitor section 16, a power converter 18, a charging relay device 40, and an ECU (Electronic Control Unit) 60. The power supply device 10 is electrically connected to a motor generator 20.

[0013] The battery 12 is a high-voltage battery that can be charged and discharged. As the battery 12, for example, a lithium ion battery pack, a nickel-metal hydride battery pack, a nickel-cadmium battery, a lead-acid battery, or the like can be used.

[0014] The capacitor unit 16 is composed of a first capacitor C1 and a second capacitor C2, which are connected in series between the positive terminal (positive bus 22) of the battery 12 and the negative terminal (negative bus 24) of the battery 12. The capacitors C1 and C2 are connected to each other at a neutral point NP1. That is, one terminal of the capacitor C1 is connected to the positive bus 22, and the other terminal is connected to the neutral point NP1. The capacitor C2 is connected to the neutral point NP1, and the other terminal is connected to the negative bus 24. Therefore, if the capacitors C1 and C2 are charged and discharged in the same way and always accumulate the same electric charge, the neutral point voltage, which is the voltage between the neutral point NP1 and the negative bus 24, is clamped to a voltage half the voltage of the battery 12. The neutral point voltage corresponds to a voltage VC2, which is the terminal voltage of the capacitor C2. Also, VC1 in FIG. 1 is the terminal voltage of the capacitor C1.

[0015] The power converter 18 is composed of an upper arm to which a positive voltage, which is the voltage between a positive bus 22 and a neutral point NP1, is supplied, and a lower arm to which a negative voltage, which is the voltage between the neutral point NP1 and a negative bus 24, is supplied. In the power converter 18, the upper arm and the lower arm are multiplexed and arranged in series between the positive bus 22 and the negative bus 24, and it is possible to output three-level three-phase AC voltages to the motor generator 20.

[0016] In addition, the power converter 18 has a U-phase arm that outputs a U-phase voltage to the motor generator 20, a V-phase arm that outputs a V-phase voltage to the motor generator 20, and a W-phase arm that outputs a W-phase voltage to the motor generator 20.

[0017] In the U-phase arm, a first switching element SU1, a second switching element SU2, a third switching element SU3, and a fourth switching element SU4 are connected in series in this order from the positive bus 22 to the negative bus 24. Each of the switching elements SU1, SU2, SU3, and SU4 is configured such that a free wheel diode is connected in inverse parallel to a semiconductor element. Note that the inverse connection is, for example, such that a cathode terminal of the diode is connected to a collector terminal of the semiconductor element, and an anode terminal of the diode is connected to an emitter terminal of the semiconductor element. An intermediate point PU1 (first intermediate point) as a connection part in the wiring connecting the first switching element SU1 and the second switching element SU2, and an intermediate point PU2 (second intermediate point) as a connection part in the wiring connecting the third switching element SU3 and the fourth switching element SU4 are connected by the diodes DU1 and DU2 such that the anode side of the two diodes DU1 and DU2 connected in series is connected to the intermediate point PU2, and the cathode side is connected to the intermediate point PU1. A connection point on the wiring connecting these two diodes DU1, DU2 is connected to the neutral point NP1 of the capacitor unit 16. In other words, the cathode side of the diode DU1 is connected to the midpoint PU1, and the anode side is connected to the neutral point NP1. The anode side of the diode DU2 is connected to the midpoint PU2, and the cathode side is connected to the neutral point NP1. In this configuration, a U-phase voltage is output to the motor generator 20 from the connection point between the second switching element SU2 and the third switching element SU3.

[0018] In the V-phase arm, the first switching element SV1, the second switching element SV2, the third switching element SV3, and the fourth switching element SV4 are connected in series in this order from the positive bus 22 to the negative bus 24. Each of the switching elements SV1, SV2, SV3, and SV4 is configured such that a free-wheeling diode is connected in inverse parallel to a semiconductor element. An intermediate point PV1 (first intermediate point) as a connection part in the wiring connecting the first switching element SV1 and the second switching element SV2, and an intermediate point PV2 (second intermediate point) as a connection part in the wiring connecting the third switching element SV3 and the fourth switching element SV4 are connected by the diodes DV1 and DV2 such that the anode side of the two diodes DV1 and DV2 connected in series is connected to the intermediate point PV2 and the cathode side is connected to the intermediate point PV1. The connection point in the wiring connecting these two diodes DV1 and DV2 is connected to the neutral point NP1 of the capacitor unit 16. In other words, the diode DV1 has a cathode connected to the midpoint PV1 and an anode connected to the neutral point NP1. The diode DV2 has an anode connected to the midpoint PV2 and a cathode connected to the neutral point NP1. In this configuration, a V-phase voltage is output to the motor generator 20 from a connection point between the second switching element SV2 and the third switching element SV3.

[0019] In the W-phase arm, the first switching element SW1, the second switching element SW2, the third switching element SW3, and the fourth switching element SW4 are connected in series in this order from the positive bus 22 to the negative bus 24. Each of the switching elements SW1, SW2, SW3, and SW4 is configured with a free wheel diode in inverse parallel to a semiconductor element. An intermediate point PW1 (first intermediate point) as a connection part in the wiring connecting the first switching element SW1 and the second switching element SW2, and an intermediate point PW2 (second intermediate point) as a connection part in the wiring connecting the third switching element SW3 and the fourth switching element SW4 are connected by the diodes DW1 and DW2 such that the anode side of the two diodes DW1 and DW2 connected in series is connected to the intermediate point PW2 and the cathode side is connected to the intermediate point PW1. The connection point in the wiring connecting these two diodes DW1 and DW2 is connected to the neutral point NP1 of the capacitor unit 16. In other words, the diode DW1 has a cathode connected to the midpoint PW1 and an anode connected to the neutral point NP1. The diode DW2 has an anode connected to the midpoint PW2 and a cathode connected to the neutral point NP1. In this configuration, a W-phase voltage is output to the motor generator 20 from a connection point between the second switching element SW2 and the third switching element SW3.

[0020] In this embodiment, each switching element of the power converter 18 may be an IGBT (Insulated Gate Bipolar Transistor) or the like.

[0021] The motor generator 20 is a rotating electric machine mounted on the electric vehicle, and acts as a motor when the DC voltage output from the battery 12 is converted to a three-phase AC voltage by the power converter 18 and supplied, generating a driving force for running the vehicle. On the other hand, the motor generator 20 acts as a generator when the vehicle is braked, recovering braking energy and outputting it as a three-phase AC voltage. This three-phase AC voltage is then converted to a DC voltage by the power converter 18 and supplied to the battery 12, thereby charging the battery 12.

[0022] The DC charger 30 is an external charger provided outside the vehicle to charge the battery 12. The DC charger 30 has a charger connection section 50 for connecting a plug (not shown) of the DC charger 30 to a connector (not shown) on the vehicle side, which has two terminals, a P terminal (positive terminal) 32P and an N terminal (negative terminal) 32N, that are electrically connected to the power supply device 10 side. A charging relay device 40 having a charging relay 42P and a charging relay 42N, and a reactor 44P are provided between the charger connection section 50 and the power converter 18.

[0023] 1, the P terminal 32P of the DC charger 30 is electrically connected to a midpoint PU1 between the switching elements SU1 and SU2 in the U-phase arm via a charging relay 42P and a reactor 44P. The N terminal 32N of the DC charger 30 is electrically connected to a midpoint PV2 between the switching elements SV3 and SV4 in the V-phase arm via a charging relay 42N.

[0024] In the power supply device 10 according to the embodiment, it is sufficient to connect the intermediate points PU1, PV1, PW1, which are the first intermediate points in the three-level inverter of any one phase among the U-phase arm, V-phase arm, and W-phase arm, to the P terminal 32P of the DC charger 30, and to connect the intermediate points PU2, PV2, PW2, which are the second intermediate points in the three-level inverter of the other phase, to the N terminal 32N of the DC charger 30.

[0025] In this manner, in the power supply device 10 according to the embodiment, a first intermediate point in the three-level inverter of any one of the U-phase arm, V-phase arm, and W-phase arm is used as a first connection terminal electrically connected to the P terminal 32P of the DC charger 30. Also, a second intermediate point in the three-level inverter of the other of the U-phase arm, V-phase arm, and W-phase arm is used as a second connection terminal electrically connected to the N terminal 32N of the DC charger 30.

[0026] The power supply device 10 of the embodiment is configured to be able to charge the battery 12 by the DC charger 30 in accordance with a plurality of voltage standards by electrically connecting the P terminal 32P of the DC charger 30 between the first switching element and the second switching element (first midpoint) in the three-level inverter of any one of the U phase, V phase, and W phase in the power converter 18, and electrically connecting the N terminal 32N of the DC charger 30 between the third switching element and the fourth switching element (second midpoint) in the three-level inverter of the other phase.

[0027] Fig. 2 is a block diagram showing the configuration of the power system according to the embodiment. The ECU 60 is an electronic control unit that controls the operation of the power supply device 10 and other components. The ECU 60 includes a charging control unit 62 and a gate signal generating unit 64. In Fig. 2, "VB" is the battery voltage, and "VH" is the charging voltage.

[0028] The charging control unit 62 receives various signals such as a charging power command signal output from a system control unit (not shown), a voltage phase signal output from a voltmeter (not shown) provided in the power converter 18, signals of voltages VC1 and VC2 of the capacitors C1 and C2 output from a voltmeter (not shown) provided in the capacitor unit 16, and a charger information signal output from the DC charger 30. The charging control unit 62 also outputs, for example, duties (U-phase duty and V-phase duty) calculated based on the charging power command signal, the voltage phase signal, and the signals of voltages VC1 and VC2 to the gate signal generating unit 64. The gate signal generating unit 64 generates gate signals for switching on and off each switching element of the power converter 18, and outputs the generated gate signals to each switching element.

[0029] In the power supply device 10 according to the embodiment, the ECU 60 has, as control modes, a direct connection mode that is applied when the maximum voltage of the DC charger 30 is equal to or higher than the battery voltage VB, and a boost mode that is applied when the maximum voltage of the DC charger 30 is lower than the battery voltage VB, when the battery 12 is charged by the DC charger 30. In the direct connection mode, the battery 12 is charged without boosting the power from the DC charger 30. In the boost mode, the battery 12 is charged by boosting the power from the DC charger 30. Note that in the power supply device 10 according to the embodiment, in both the direct connection mode and the boost mode, the battery 12 is charged without flowing current from the DC charger 30 to the motor generator 20.

[0030] The charging control unit 62 compares the maximum voltage of the DC charger 30 with the battery voltage VB based on the charger information signal from the DC charger 30. Then, if the maximum voltage of the DC charger 30 is equal to or higher than the battery voltage VB, the charging control unit 62 charges the battery 12 with the DC charger 30 in the direct connection mode. On the other hand, if the maximum voltage of the DC charger 30 is lower than the battery voltage VB, the charging control unit 62 charges the battery 12 with the DC charger 30 in the boost mode.

[0031] In addition, the selection between the direct connection mode and the boost mode may be performed, for example, by an operator such as a driver operating a switch provided on the electric vehicle equipped with the power supply device 10 based on the specifications (maximum voltage) of the DC charger 30.

[0032] Fig. 3 is a diagram showing the circuit state when the battery 12 is charged by the DC charger 30 in the direct connection mode. In Fig. 3, the maximum voltage of the DC charger 30 is 400 [V], and the battery voltage VB is 600 [V]. In Fig. 3, the switching elements that are in the on state are circled.

[0033] 3, when the battery 12 is charged by the DC charger 30 in the direct connection mode, first, the ECU 60 switches the first switching element SU1 of the U-phase arm and the fourth switching element SW4 of the V-phase arm from off to on, and keeps the other switching elements off. Next, the ECU 60 switches the charging relays 42P, 42N of the charging relay device 40 from off to on, supplying a DC voltage from the DC charger 30 to the battery 12 via the power converter 18, and charging the battery 12.

[0034] The first switching element SU1 and the fourth switching element SV4 may be turned off because current flows through their respective freewheel diodes. This causes all switching elements of the power converter 18 to be in the off state, eliminating the need to perform a switching operation to switch each switching element of the power converter 18 between on and off, improving charging efficiency and reducing the need to add an inverter element or cooling mechanism for charging. On the other hand, by turning on the first switching element SU1 and the fourth switching element SV4, it is possible to ensure durability when a current flows through the first switching element SU1 and the fourth switching element SV4.

[0035] During charging in the direct connection mode, the on and off states of the switching elements of the power converter 18 are fixed, thereby reducing switching loss. Also, switching elements that are unrelated to the current flow may be switched either on or off.

[0036] FIG. 4 is a diagram showing a circuit state in a first charging mode when the battery 12 is charged by the DC charger 30 in the boost mode. FIG. 5 is a diagram showing a circuit state in a second charging mode when the battery 12 is charged by the DC charger 30 in the boost mode. FIG. 6 is a diagram showing a circuit state in a third charging mode when the battery 12 is charged by the DC charger 30 in the boost mode. In FIG. 4, FIG. 5, and FIG. 6, the switching elements in the ON state are circled. FIG. 7 is a diagram showing an example of the timing of switching between the ON state of the charging of the capacitor C1 and the ON state of the charging of the capacitor C2. FIG. 7 is a graph showing the waveforms of the time changes of each voltage, each current, and the ON and OFF of each switching element in the boost mode.

[0037] In this embodiment, as shown in Fig. 4, in the boost mode, a state in which a current flows from the DC charger 30 to the capacitor C1 to charge the capacitor C1 is referred to as a "capacitor C1 charging on state" and is a first charging mode. Also, in this embodiment, as shown in Fig. 5, in the boost mode, a state in which a current flows from the DC charger 30 to the capacitor C2 to charge the capacitor C2 is referred to as a "capacitor C2 charging on state" and is a second charging mode. Also, in this embodiment, as shown in Fig. 6, in the boost mode, a state in which a current flows from the DC charger 30 to the capacitors C1 and C2 to charge the capacitors C1 and C2 is referred to as a "capacitor C1 and C2 charging on state" and is a third charging mode.

[0038] In the boost mode, the charging control unit 62 performs feedback control (PI control) so that the voltages VC1 and VC2 of the capacitors C1 and C2 are equal. In this feedback control (PI control), the duties (U-phase duty and V-phase duty) when the charging of the capacitor C1 is on and when the charging of the capacitor C2 is on are calculated using the following formulas (1) and (2).

[0039] U phase duty=(2×Vcha-VB) / VB)+{Kp(VC1-VC2)+Ki∫(VC1-VC2)dt}···(1)

[0040] V phase duty=(2×Vcha-VB) / VB)-{Kp(VC1-VC2)+Ki∫(VC1-VC2)dt}···(2)

[0041] In the above formulas (1) and (2), "Vcha" is the maximum voltage of the DC charger 30, "Kp" is the proportional gain, and "Ki" is the integral gain.

[0042] In addition, "(2×Vcha-VB) / VB)" in the above formulas (1) and (2) represents an arbitrary boost ratio calculation term. In addition, "{Kp(VC1-VC2)+Ki∫(VC1-VC2)dt}" in the above formulas (1) and (2) represents a correction term that equalizes the voltages VC1 and VC2 of the capacitors C1 and C2.

[0043] Information on the duties (U-phase duty and V-phase duty) calculated in this manner is output from the charge control unit 62 to the gate signal generation unit 64.

[0044] During boost mode, the gate signal generating unit 64 generates a gate signal for switching each switching element of the power converter 18 on and off based on the duty (U-phase duty and V-phase duty) and the carrier period T, etc., so that the charging of the capacitor C1 is on or the charging of the capacitor C2 is on, and outputs the generated gate signal to each switching element.

[0045] When charging the battery 12 with the DC charger 30 in the boost mode, the voltages VC1 and VC2 of the capacitors C1 and C2 are controlled to be 1 / 2 the battery voltage VB, and the battery voltage VB has an arbitrary boost ratio of 1 to 2 times the voltage of the DC charger 30.

[0046] In the first charging mode in which the charging of the capacitor C1 shown in Fig. 4 is turned on, the ECU 60 switches the first switching element SU1 in the U-phase arm and the second switching element SV2 and the second switching element SV3 in the V-phase arm from off to on, and turns the other switching elements off. As a result, the current output from the P terminal 32P of the DC charger 30 to the midpoint PU1 of the U-phase arm passes through the first switching element SU1 of the U-phase arm, the capacitor C1, and the second switching element SV2 and the third switching element SV3 of the V-phase arm, and is input from the midpoint PV2 of the V-phase arm to the N terminal 32N of the DC charger 30. As a result, when the charging of the capacitor C1 is turned on, the capacitor C1 is charged by the power from the DC charger 30, and the voltage VC1 increases.

[0047] The first switching element SU1 may be turned off because a current flows through the freewheel diode. On the other hand, by turning on the first switching element SU1, it is possible to ensure the durability of the first switching element SU1 when a current flows through it.

[0048] In the second charging mode shown in Fig. 5 in which the charging of the capacitor C2 is turned on, the ECU 60 switches the second switching element SU2 and the third switching element SU3 in the U-phase arm and the fourth switching element SV4 in the V-phase arm from off to on, and turns the other switching elements off. As a result, a current output from the P terminal 32P of the DC charger 30 to the midpoint PU1 of the U-phase arm passes through the second switching element SU2 and the third switching element SU3 in the U-phase arm, the capacitor C2, and the fourth switching element SV4 in the V-phase arm, and is input from the midpoint PV2 of the V-phase arm to the N terminal 32N of the DC charger 30. As a result, when the charging of the capacitor C2 is turned on, the capacitor C2 is charged by the power from the DC charger 30, and the voltage VC2 increases.

[0049] The fourth switching element SV4 may be turned off because a current flows through the freewheel diode. On the other hand, by turning on the fourth switching element SV4, it is possible to ensure the durability of the fourth switching element SU4 when a current flows through it.

[0050] In the third charging mode in which the charging of the capacitors C1 and C2 shown in Fig. 6 is turned on, the ECU 60 switches the first switching element SU1 in the U-phase arm and the fourth switching element SV4 in the V-phase arm from off to on, and turns the other switching elements off. As a result, a current output from the P terminal 32P of the DC charger 30 to the midpoint PU1 of the U-phase arm passes through the first switching element SU1 in the U-phase arm, the capacitor C1, the capacitor C2, and the fourth switching element SV4 in the V-phase arm, and is input from the midpoint PV2 of the V-phase arm to the N terminal 32N of the DC charger 30. As a result, when the charging of the capacitors C1 and C2 is turned on, the capacitors C1 and C2 are charged by the power from the DC charger 30, and the voltages VC1 and VC2 become high.

[0051] The first switching element SU1 and the fourth switching element SV4 may be turned off because current flows through their respective freewheeling diodes. On the other hand, by turning on the first switching element SU1 and the fourth switching element SV4, it is possible to ensure durability when current flows through the first switching element SU1 and the fourth switching element SV4.

[0052] In the power supply device 10 according to the embodiment, the ECU 60 controls the on / off switching of each switching element to alternate between one of the first and second charging modes and the third charging mode when the battery 12 is charged by the DC charger 30 in the boost mode. That is, for example, as shown in Fig. 7, when the battery 12 is charged by the DC charger 30 in the boost mode, the ECU 60 controls the on / off switching of each switching element SU1, SU2, SU3, SU4 in the U-phase arm and each switching element SV1, SV2, SV3, SV4 in the V-phase arm to alternate between the first charging mode, the third charging mode, the second charging mode, the third charging mode, the first charging mode, the third charging mode, the second charging mode, ...

[0053] As a result, in the power supply device 10 according to the embodiment, a period in which the capacitors C1 and C2 are charged in series in the third charging mode is inserted between periods in which the capacitors C1 and C2 are alternately charged in the first charging mode and the second charging mode, thereby making it possible to perform a boost operation at an arbitrary boost ratio of 1 to 2. Therefore, the power supply device 10 according to the embodiment can obtain an arbitrary boost ratio for the voltage on the DC charger 30 side, so that it is possible to charge the battery 12 even if its voltage is high. In addition, since the boost ratio can be set arbitrarily, the degree of freedom in designing the battery voltage is increased.

[0054] In addition, in the boost mode, power is not supplied to the motor generator 20, and therefore the coil of the motor generator 20 is not used as a reactor to boost the voltage. Therefore, since the motor generator 20 does not rotate during charging in the boost mode, there is no need to provide a relay that can cut off the power supply between the power supply device 10 and the motor generator 20, and it is possible to reduce the cost and size of the power supply device 10.

[0055] In addition, in the boost mode, the voltage difference between the capacitors C1, C2 and the DC charger 30 becomes close to 0 [V], so that the current ripple due to the voltage difference can be reduced. As a result, the reactor provided between the DC charger 30 and the power converter 18 can be made smaller, or the reactor can be eliminated from between the DC charger 30 and the power converter 18, so that the power supply device 10 can be made smaller, less expensive, and more efficient.

[0056] Furthermore, in the power supply device 10 according to the embodiment, the power converter 18 may be configured using an inverter with more levels than a three-level inverter. In this case, the P terminal 32P and the N terminal 32N of the DC charger 30 may be electrically connected between switching elements other than between switching elements that output power from the power converter 18 to the motor generator 20. [Explanation of symbols]

[0057] 10 Power supply 12 Battery 16 Capacitor section 18 Power Converter 20 Motor generator 22 Positive busbar 24 negative bus 30 DC charger 32N N terminal 32P P terminal 40 Charging relay device 42N, 42P Charging relay 44P Reactor 50 Charger connector 60 ECU 62 Charging control unit 64 Gate signal generator C1, C2 capacitors DU1,DU2,DV1,DV2,DW1,DW2 Diodes SU1, SV1, SW1 Switching elements SU2, SV2, SW2 switching elements SU3, SV3, SW3 switching elements SU4, SV4, SW4 switching elements

Claims

[Claim 1] A storage battery, a capacitor section in which a first capacitor and a second capacitor are connected in series between a positive terminal and a negative terminal of the storage battery; a first diode having a cathode connected to a wiring connecting the first switching element and the second switching element and an anode connected to a wiring connecting the first capacitor and the second capacitor, and a second diode having an anode connected to a wiring connecting the third switching element and the fourth switching element and a cathode connected to a wiring connecting the first capacitor and the second capacitor, the three-level inverter being capable of selectively outputting a voltage of one of three different voltage values ​​to a motor generator by switching on and off each of the first switching element, the second switching element, the third switching element, and the fourth switching element, the three-level inverter being connected in parallel with the storage battery for three phases, U phase, V phase, and W phase; A control device that controls switching on and off of each switching element of the power converter; a first connection terminal electrically connected to a P terminal of a DC charger between the first switching element and the second switching element in the three-level inverter of any one of the U phase, the V phase, and the W phase; a second connection terminal electrically connected to an N terminal of the DC charger between the third switching element and the fourth switching element in the three-level inverter of the other one of the U phase, the V phase, and the W phase; A power supply device comprising: a first charging mode in which the first capacitor is charged, a second charging mode in which the second capacitor is charged, and a third charging mode in which the first capacitor and the second capacitor are charged, The control device controls the switching on and off of each switching element to alternate between the first charging mode and one of the second charging mode and the third charging mode, such as the first charging mode, the third charging mode, the second charging mode, the third charging mode, and the first charging mode.

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