Power System

Abstract

It enables charging of the power storage device using power from an external three-phase AC power source. [Solution] The power supply system includes a first switch provided on the power line for connecting and disconnecting the first inverter side and the second inverter side, a connector connected to the three-phase second arm and connectable to an external three-phase AC power source, a second switch provided on the power line for connecting and disconnecting the three-phase second arms to each other, a third switch provided on the power line for connecting and disconnecting the storage device side and the first inverter side, and an isolated DC / DC converter provided on the power line in parallel with the third switch for exchanging power between the first inverter side and the storage device side via the third switch, involving voltage conversion.

Description

[Technical Field]

[0001] The present disclosure relates to power supply systems. [Background technology]

[0002] Conventionally, a power supply system has been proposed that includes a power storage device, a motor having a three-phase open winding, a first inverter connected to a power line to which the power storage device is connected, connected to one end of the three-phase open winding, and having a three-phase first arm, and a second inverter connected to the power line, connected to the other end of the three-phase open winding, and having a three-phase second arm (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-85914 Summary of the Invention [Problem to be solved by the invention]

[0004] In a power supply system having the above-described hardware configuration, it is desired to be able to charge a power storage device using power from an external three-phase AC power supply. In this case, it is also desirable to miniaturize the circuitry required for charging the power storage device, reduce noise, and reduce the impact of AC power leakage current on the power storage device. The power supply system of the present disclosure has a primary objective of being able to charge a power storage device using power from an external three-phase AC power supply. [Means for solving the problem]

[0005] The power supply system of the present disclosure employs the following means to achieve the above-mentioned primary object: The power supply system of the present disclosure is a power supply system including a power storage device, a motor having a three-phase open winding, a first inverter connected to a power line to which the power storage device is connected and connected to one end of the three-phase open winding and having a three-phase first arm, and a second inverter connected to the power line on the opposite side of the first inverter from the power storage device and connected to the other end of the three-phase open winding and having a three-phase second arm, and further including a second inverter provided on the power line for connecting and disconnecting the first inverter side and the second inverter side. a first switch, a connector connected to the three-phase second arm and connectable to an external three-phase AC power source, a second switch provided on the power line for connecting and disconnecting the three-phase second arms to each other, a third switch provided on the power line for connecting and disconnecting the power storage device side and the first inverter side, and an isolated DC / DC converter provided on the power line in parallel with the third switch for exchanging power with voltage conversion between the first inverter side and the power storage device side via the third switch.

[0006] The power supply system of the present disclosure includes a first switch provided on the power line for connecting and disconnecting the first inverter side and the second inverter side, a connector connected to the three-phase second arm and connectable to an external three-phase AC power supply, a second switch provided on the power line for connecting and disconnecting the three-phase second arms to each other, a third switch provided on the power line for connecting and disconnecting the power storage device side and the first inverter side, and an isolated DC / DC converter provided on the power line in parallel with the third switch for exchanging power with voltage conversion between the first inverter side and the power storage device side via the third switch. Therefore, when the three-phase AC power supply and the connector are connected, the first, second, and third switches are turned off, and AC power from the three-phase AC power supply is converted into DC power with power factor correction and power adjustment by the second inverter, the motor, and the first inverter, and the voltage is further converted by the DC / DC converter and supplied to the power storage device, thereby charging the power storage device. Furthermore, by performing power factor correction and power adjustment using the second inverter, motor, and first inverter, the circuit for charging the power storage device can be made smaller than when a dedicated power factor correction circuit is separately provided. Also, by electrically isolating the first inverter side from the power storage device side using the third switch and DC / DC converter, noise can be reduced and the impact of AC power leakage current on the power storage device side can be reduced. As a result, costs can be reduced. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic configuration diagram of a power supply system 10 according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a schematic diagram of a power supply system 110 according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram of a power supply system 10 according to an embodiment of the present disclosure. The power supply system 10 is installed in an electric vehicle, a hybrid vehicle, a fuel cell vehicle, or the like. As shown in the figure, the power supply system 10 includes a battery 12, a motor 20, a first inverter 22, a second inverter 24, power lines 28 (a positive line 28p and a negative line 28n), system main relays 34p and 34n, a switch 36 (a first switch), a switch 38, charging lines 40u, 40v, and 40w, a connector 42, switches 44a and 44b (a second switch), switches 46u, 46v, 46w, and 46n, switches 50p and 50n (a third switch), a power line 52 (a positive line 52p and a negative line 52n), a DC / DC converter 54, a switch 56, and an ECU 60 (a control device).

[0009] Battery 12 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is connected to power line 28. Motor 20 is configured as a three-phase AC motor, and includes a rotor with a permanent magnet embedded in a rotor core, and a stator with three-phase (U-phase, V-phase, W-phase) coils (open windings) wound around a stator core. The rotor is connected to a drive shaft that is connected to drive wheels via a differential gear.

[0010] The first inverter 22 is connected to the power line 28. The first inverter 22 includes six transistors T11 to T16 (six first arms) as switching elements and six diodes D11 to D16 connected in parallel to the six transistors T11 to T16, respectively. For example, Nch-MOSFETs or IGBTs are used for the transistors T11 to T16. The transistors T11 to T16 are arranged in pairs, two at a time, on the source side and two at the sink side of the positive line 28p and the negative line 28n. Each of the connection points of two transistors forming a pair of the transistors T11 to T16 is connected to one end of the three-phase coil of the motor 20. A smoothing capacitor 30 is connected to the power line 28 near the first inverter 22.

[0011] The second inverter 24 is connected to the power line 28 on the opposite side of the first inverter 22 from the battery 12. Similar to the first inverter 22, the second inverter 24 includes six transistors T21 to T26 (six second arms) as switching elements and six diodes D21 to D26. The transistors T21 to T26 are, for example, Nch-MOSFETs or IGBTs. The transistors T21 to T26 are arranged in pairs, two at a time, on the source side and two at the sink side of the positive line 28p and the negative line 28n. The connection points of the paired two transistors T21 to T26 are connected to the other ends of the three-phase coils of the motor 20. A smoothing capacitor 32 is connected to the power line 28 near the second inverter 24. In this embodiment, the battery 12, capacitor 30, first inverter 22, second inverter 24, and capacitor 32 are connected to the power line 28 in this order from the left side of FIG. 1.

[0012] System main relays 34p, 34n are provided between the connection point of positive line 28p and negative line 28n with battery 12 and the connection point of capacitor 30, respectively, and connect and disconnect battery 12 side and capacitor 30 side. Switch 36 is provided between the connection point of positive line 28p with first inverter 22 and the connection point of second inverter 24, and connects and disconnects first inverter 22 side and second inverter 24 side. Switch 38 is provided between the connection point of positive line 28p with second inverter 24 and the connection point of capacitor 32, and connects and disconnects second inverter 24 side and capacitor 32 side.

[0013] The charging lines 40u, 40v, and 40w are connected to the connection points between the positive line 28p and the transistors T21, T22, and T23, respectively, and are also connected to a connector 42. The charging line 40n is connected to the negative line 28n and to a connector 42. The connector 42 is configured to be connectable to a connector 84. The connector 84 is connected to the U phase, V phase, W phase, and neutral point of a three-phase AC power supply 80 via four power supply lines 82u, 82v, 82w, and 82n. When the connector 42 and the connector 84 are connected, the charging lines 40u, 40v, 40w, and 40n are connected to the power supply lines 82u, 82v, 82w, and 82n, respectively.

[0014] The switch 44a is provided on the positive line 28p between the node with the transistor T21 and the node with the transistor T22, and connects and disconnects the transistor T21 side from the transistor T22 side. The switch 44b is provided on the positive line 28p between the node with the transistor T22 and the node with the transistor T23, and connects and disconnects the transistor T22 side from the transistor T23 side.

[0015] Switches 46u, 46v, and 46w are provided on charging lines 40u, 40v, and 40w, respectively, and connect and disconnect the connection points between positive line 28p and transistors T21, T22, and T23, and connector 42. Switch 46n is provided on charging line 40n and disconnects the connection between negative line 28n and connector 42.

[0016] The switches 50p and 50n are respectively provided on the positive line 28p and the negative line 28n between the connection points of the system main relays 34p and 34n and the capacitor 30, and connect and disconnect the system main relays 34p and 34n sides from the capacitor 30. The switches 50p and 50n are preferably insulating switches that can ensure sufficient insulation when in the off state. Note that the switches 36, 38, 44a and 44b, and 46u, 46v, 46w, and 46n may be insulating switches or semiconductor switches.

[0017] The positive line 52p and the negative line 52n are connected between the system main relays 34p, 34n and the switches 50p, 50n of the positive line 28p and the negative line 28n, respectively, and are connected to the first inverter 22 side of the switches 50p, 50n. The DC / DC converter 54 is configured as an isolated DC / DC converter and includes a transformer and switching elements. The switches 56p, 56n are provided between the DC / DC converter 54 and a connection point between the positive line 52n and the negative line 52n and the positive line 28p and the negative line 28n, which is closer to the first inverter 22 than the switches 50p, 50n.

[0018] The ECU 60 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, as well as various drive circuits and logic ICs. The ECU 60 receives signals from various sensors. For example, the rotational position θm of the rotor of the motor 20 is input from the rotational position sensor 14a, and the phase currents Iu, Iv, and Iw of the motor 20 are input from the current sensors 14u, 12v, and 12w. The ECU 60 also receives the voltage Vb of the battery 12 from the voltage sensor 12v and the current Ib of the battery 12 from the current sensor 12i. The voltage VH of the capacitor 30 is input from the voltage sensor 30v, and the voltage VL of the capacitor 32 is input from the voltage sensor 32v.

[0019] Various control signals are output from the ECU 60. For example, control signals are output to the transistors T11 to T16 of the first inverter 22 and the transistors T21 to T26 of the second inverter 24. Control signals are also output to the system main relays 34p and 34n, the switch 36, the switch 38, the switches 44a and 44b, the switches 46u, 46v, 46w, and 46n, the switches 50p and 50n, and the DC / DC converter 54. The ECU 60 calculates the electrical angle θe and the rotation speed Nm of the motor 20 based on the rotational position θm of the rotor of the motor 20, and calculates the state of charge (SOC) of the battery 12 based on the integrated value of the current Ib of the battery 12.

[0020] In power supply system 10 of the embodiment, when connector 42 and connector 84 are connected, switches 36, 38, 44a, 44b, and 50p, 50n are turned off, and system main relays 34p, 34n, switches 46u, 46v, 46w, 46n, and switches 56p, 56n are turned on. Then, by control of first inverter 22, second inverter 24, and DC / DC converter 54 by ECU 60, three-phase AC power from three-phase AC power supply 80 is converted by second inverter 24, motor 20, and first inverter 22 into DC power with power factor correction and power adjustment, and further voltage conversion is performed by DC / DC converter 54 before supplying the DC power to battery 12 and charging battery 12. Furthermore, by converting three-phase AC power to DC power with power factor correction and power adjustment using second inverter 24, motor 20, and first inverter 22, the circuit for charging the power storage device can be made smaller than when a dedicated power factor correction circuit or the like is separately provided. Also, by electrically isolating battery 12 from first inverter 22 using switches 50p, 50n and DC / DC converter 54, it is possible to reduce noise and the impact of AC power leakage current on battery 12. As a result, costs can be reduced.

[0021] In the above-described embodiment, the power supply system 10 includes the switches 56p and 56n, but this does not necessarily have to be included.

[0022] 1, in the power supply system 10, the system main relays 34p, 34n and the switches 50p, 50n (third switches) are provided on the positive line 28p and the negative line 28n, respectively. Furthermore, one end of the positive line 52p and one end of the negative line 52n are connected between the system main relays 34p, 34n and the switches 50p, 50n on the positive line 28p and the negative line 28n, respectively, and the other end of the positive line 52p and the negative line 52n are connected to the first inverter 22 side of the switches 50p, 50n, respectively. However, the present invention is not limited to this. For example, as shown in a modified power supply system 110 of Figure 2, the switches 50p, 50n may be omitted from the power supply system 10 of Figure 1, and one end of the positive line 52p and one end of the negative line 52n may be connected to the positive line 28p and one end of the negative line 28n closer to the battery 12 than the system main relays 34p, 34n (third switch).

[0023] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be described below. In the embodiment, the battery 12 corresponds to the "power storage device," the motor 20 corresponds to the "motor," the first inverter 22 corresponds to the "first inverter," the second inverter 24 corresponds to the "second inverter," the switch 36 corresponds to the "first switch," the connector 42 corresponds to the "connector," the switches 44a and 44b correspond to the "second switch," the switches 50p and 50n correspond to the "third switch," and the DC / DC converter 54 corresponds to the "DC / DC converter."

[0024] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0025] The above describes the forms for implementing the present disclosure using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0026] The present disclosure is applicable to the power supply system manufacturing industry and the like. [Explanation of symbols]

[0027] 10 Power supply system, 12 Battery, 12i, 14u, 14v, 14w Current sensor, 12v, 30v, 32v Voltage sensor, 14a Rotational position sensor, 20 Motor, 22 First inverter, 24 Second inverter, 28, 52 Power line, 28n, 52n Negative line, 28p, 52p Positive line, 30, 32 Capacitor, 34p System main relay, 36 Switch, 38, 50p, 50n Relay, 40n, 40u, 40v, 40w Charging line, 42, 84 Connector, 44a, 44b, 46n, 46u, 46v, 46w Switch, 54 DC / DC converter, 60 ECU, 80 AC power supply, 82n, 82u, 82v, 82w Power supply line, D11 to D16, D21 to D26 Diodes, T11~T16, T21~T26 transistors.

Claims

[Claim 1] a first inverter connected to a power line to which the power storage device is connected, connected to one end of the three-phase open winding, and having a three-phase first arm; and a second inverter connected to the power line on an opposite side of the first inverter from the power storage device, connected to the other end of the three-phase open winding, and having a three-phase second arm, a first switch provided on the power line for connecting and disconnecting the first inverter side and the second inverter side; a connector connected to the three-phase second arm and connectable to an external three-phase AC power supply; a second switch provided on the power line for connecting and disconnecting the three-phase second arms to each other; a third switch provided on the power line for connecting and disconnecting the power storage device side and the first inverter side; an isolated DC / DC converter that is provided in parallel with the third switch on the power line and exchanges power with voltage conversion between the first inverter side and the power storage device side of the third switch; A power supply system comprising:

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