Power conversion system

Abstract

To allow supply of stable electric power to a load.SOLUTION: An electric power conversion system 1 includes: a first electric power conversion unit 5 connected to a battery 15; a second electric power conversion unit 7 connected to the battery 15 to be connected to the first electric power conversion unit 5 in parallel; and an electric power propagation circuit 9. The first electric power conversion unit 5 has a DC / DC converter 23. The second electric power conversion unit 7 includes an AC inverter 29 and an AC outlet 43 and an AC-DC converter 33 connected to an output end of the AC inverter 29. The output end of the DC-DC converter 23 is connected to a first load which has to be usable when a vehicle travels. The output end of the AC-DC converter 33 is connected to a second load as an item equipped in the vehicle. The electric power propagation circuit 9 makes the output end of the AC-DC converter 33 and the first load electrically connected to each other when supply of DC power from the DC-DC converter 23 to the first load is abnormally stopped.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a power conversion system.

Background Art

[0002] Conventionally, as a vehicle system, a system that converts the power of a battery by a DC / DC converter and supplies it to a load has been used (for example, see Patent Document 1 below).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the conventional system as described above, for example, when an abnormality occurs in the DC / DC converter and the power supply from the DC / DC converter stops abnormally, the power supply to the load connected to the output terminal of the DC / DC converter may be interrupted. Even in such a power failure, a stable power supply to the load used for vehicle running is desired.

[0005] Therefore, the present invention has been made in view of such problems, and an object thereof is to provide a power conversion system capable of stably supplying power to a load used for vehicle running.

Means for Solving the Problems

[0006] To solve the above problems, the power conversion system according to the present invention comprises a first power conversion unit connected to a battery, a second power conversion unit connected to the battery so as to be connected in parallel with the first power conversion unit, and a power transmission circuit connected to the output terminal of the second power conversion unit. The first power conversion unit has a DC / DC converter that converts DC power supplied from the battery into voltage and outputs it, and the second power conversion unit has an inverter that converts DC power supplied from the battery into AC power and outputs it, and an AC outlet and an AC / DC converter connected to the output terminal of the inverter. A first load, which is essential to be usable when the vehicle is running, is connected to the output terminal of the DC / DC converter, and a second load, which is an in-vehicle equipment, is connected to the output terminal of the AC / DC converter. The power transmission circuit has wiring connecting the output terminal of the AC / DC converter and the first load, and a semiconductor element provided on the wiring. The semiconductor element causes conductivity between the output terminal of the AC / DC converter and the first load when the supply of DC power from the DC / DC converter to the first load is abnormally stopped.

[0007] The power conversion system comprises a first power conversion unit and a second power conversion unit connected to a battery. In the first power conversion unit, a first load essential for vehicle operation is connected to the output terminal of a DC / DC converter. In the second power conversion unit, a second load of in-vehicle equipment is connected to the output terminal of an AC / DC converter connected to the battery via an inverter. Furthermore, the system includes a power transmission circuit having wiring connecting the output terminal of the AC / DC converter to the first load and a semiconductor element provided on the wiring. In the event of an abnormal interruption in the supply of DC power to the first load, the semiconductor element causes conductivity between the output terminal and the first load. As a result, even if the power supply from the DC / DC converter to the first load is interrupted, DC power can still be supplied from the AC / DC converter to the first load, enabling a stable power supply to the first load, which is essential for vehicle operation.

[0008] In a power conversion system, it is preferable that the semiconductor element is a transistor. With this configuration, DC power can be stably supplied from the output terminal of the AC / DC converter to the first load, and power supply to the load used for vehicle operation can be achieved with low loss.

[0009] Furthermore, in the power conversion system, it is preferable that the semiconductor element is a diode in which the anode is connected to the output terminal of the AC / DC converter and the cathode is connected to the output terminal of the DC / DC converter. In this case, the supply of DC power from the output terminal of the AC / DC converter to the first load can be started in response to the voltage change on the output terminal side of the DC / DC converter, enabling a stable power supply without momentary interruptions in the power supply to the load used for vehicle operation. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a power conversion system that can provide a stable power supply to loads that are essential to be usable when a vehicle is in motion. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a circuit diagram showing a schematic configuration of a power conversion system 1 according to one embodiment of the present invention. [Figure 2] Figure 2 is a circuit diagram showing the power supply path in a power conversion system 1 according to one embodiment of the present invention. [Figure 3] Figure 3 is a circuit diagram showing the schematic configuration of the power conversion system 901 according to the comparative example. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described in detail below with reference to the attached drawings. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant descriptions will be omitted.

[0013] Figure 1 is a circuit diagram showing a schematic configuration of a power conversion system 1 according to one embodiment of the present invention. The power conversion system 1 shown in the figure is a system that distributes power supplied from a battery (storage battery) to various loads. The power conversion system 1 is mounted on a vehicle. The power conversion system 1 comprises a first junction box 3, a first power conversion unit 5, a second power conversion unit 7, a power transmission circuit 9, a control circuit 11A, and a control circuit 11B.

[0014] The first junction box 3 is a box that connects electrical wiring W1 to two electrical wirings W2 and W3. That is, the first junction box 3 has two first connection points J12 and J13 that connect one terminal T1i of electrical wiring W1, which is brought inside, to one end T2i and T3i of the two electrical wirings W2 and W3, which are brought inside. Each of the two first connection points J12 and J13 is, for example, a fuse. The first junction box 3 only needs to be a box that connects electrical wiring W1 to multiple electrical wirings.

[0015] The other terminal T1o of the electrical wiring W1 is connected to the positive terminal of the battery 15 via a switch 13 outside the first junction box 3. The negative terminal of the battery 15 is connected to a reference potential (e.g., ground potential). The battery 15 supplies DC power to the electrical wiring W1 when the switch 13 is conductive. The switch 13 is a component that can switch between conductive and non-conductive states, such as a MOS (Metal Oxide Semiconductor) FET.

[0016] The other end T2o of electrical wiring W2 is connected to the first power conversion unit 5 outside the first junction box 3, and the other end T3o of electrical wiring W3 is connected to the second power conversion unit 7 outside the first junction box 3. In this embodiment, the first power conversion unit 5 and the second power conversion unit 7 are connected to the battery 15 via electrical wiring W2 and W3, respectively, the first connection parts J12 and J13, respectively, electrical wiring W1, and the switch 13.

[0017] The first power conversion unit 5 includes a DC / DC converter 23, a second junction box 25, and an auxiliary battery 24. The input terminal of the DC / DC converter 23 is connected to the other terminal T2o of the electrical wiring W2. The DC / DC converter 23 converts the DC power supplied from the battery 15 through the switch 13, electrical wiring W1, first connection J12, and electrical wiring W2 into a voltage (for example, stepping it down to 12V) and outputs it. The output terminal of the DC / DC converter 23 is connected to one terminal T4o of the electrical wiring W4, and is connected to the auxiliary battery 24 and the second junction box 25, which are connected to the electrical wiring W4, via the electrical wiring W4.

[0018] The second junction box 25 is a box that connects electrical wiring W4 to multiple electrical wirings. For example, the second junction box 25 connects electrical wiring W4 to six electrical wirings W5, W6, W7, W8, W9, W10 provided for each load. In this embodiment, the second junction box 25 has six second connection points J65, J66, J67, J68, J69, J610 that connect the other end T4i of the electrical wiring W4 that is brought inside to the second junction box 25 to one end T5i, T6i, T7i, T8i, T9i, T10i of the six electrical wirings W5, W6, W7, W8, W9, W10 that are brought inside. Each of the six second connection points J65, J66, J67, J68, J69, J610 is, for example, a circuit in which a fuse and a switch are connected in series. The second junction box 25 only needs to connect electrical wiring W4 to multiple electrical wires.

[0019] The other ends T5o, T6o, T7o, T8o, T9o, T10o of the electrical wirings W5, W6, W7, W8, W9, W10 are respectively connected to loads (first loads) 27A, 27B, 27C, 27D, 27E, 27F. That is to say, it can be said that the loads (first loads) 27A, 27B, 27C, 27D, 27E, 27F are connected to the output end of the DC / DC converter 23 via the electrical wirings W5, W6, W7, W8, W9, W10, the second junction box 25, and the electrical wiring W4. The loads 27A, 27B, 27C, 27D, 27E, 27F are loads that must be driven to be usable when the vehicle equipped with the power conversion system 1 travels. For example, they are any of the headlamps, wipers, ECU (Electronic Control Unit), various meters, various sensors, actuators, winkers, and brake lamps provided on the vehicle.

[0020] The second power conversion unit 7 has an AC inverter 29, a power distribution unit 31, and an AC / DC converter 33. The input end of the AC inverter 29 is connected to the other end T3o of the electrical wiring W3. The AC inverter 29 converts the DC power supplied from the battery 15 via the switch 13, the electrical wiring W1, the first connection part J13, and the electrical wiring W3 into AC power (for example, converts it into 100V AC power) and outputs it. The output end of the AC inverter 29 is connected to one end T11o of the electrical wiring W11 and is connected to the power distribution unit 31 via the electrical wiring W11.

[0021] The power distribution unit 31 is a circuit unit that connects the electrical wiring W11 to the AC / DC converter 33 and the electrical wiring. For example, the power distribution unit 31 connects the electrical wiring W11 to the AC / DC converter 33 and one electrical wiring W12. In this embodiment, the power distribution unit 31 includes third connection parts J71 and J72 that connect the other end T11i of the electrical wiring W11 to the input terminal of the AC / DC converter 33 and one end T12i of the electrical wiring W12. An AC outlet 43 is connected to the other end T12o of the electrical wiring W12. Each of the third connection parts J71 and J72 has at least a switch, and in this embodiment, it has a series-connected switch 37 and an ammeter 39. The switch 37 is an element that can switch between conducting and non-conducting, for example, a MOS (Metal Oxide Semiconductor) FET. The ammeter 39 measures the magnitude of the alternating current that branches off from the electrical wiring W11 and flows into the respective third connection points J71 and J72. The power distribution unit 31 connects the electrical wiring W11 to at least one AC / DC converter and at least one electrical wiring, and may be equipped with multiple switches.

[0022] The AC / DC converter 33 receives AC power input from the AC inverter 29 via the electrical wiring W11 and the third connection J71, and converts this AC power to DC power (for example, 12V DC power) and outputs it. The output terminal of the AC / DC converter 33 is connected to a load (second load) 41A via the electrical wiring W13, and the DC power output by the AC / DC converter 33 is supplied to the load 41A. In other words, the load (second load) 41A is connected to the output terminal of the AC / DC converter 33 via the electrical wiring W13. The load 41A is an in-vehicle piece of equipment that is not essential for the vehicle to run, such as a display, audio system, or interior lights. Note that the number of loads connected to the output terminal of the AC / DC converter 33 may be one or more.

[0023] With the configuration of the above-described power distribution unit 31, an AC outlet 43 and an AC / DC converter 33 are connected in parallel to the output terminal of the AC inverter 29. As a result, the power output from the AC inverter 29 is distributed to the load 41A and the load connected to the AC outlet 43.

[0024] The power transmission circuit 9 includes an electrical wiring W19 that connects the output terminal of the AD / DC converter 33 and the first load (load 27E), a semiconductor element provided on the electrical wiring W19, and a diode 45. The semiconductor element is an element that can switch between conduction and non-conduction, and is, for example, a MOS (Metal Oxide Semiconductor) FET, an IGBT, a diode, or the like. The electrical wiring W19 of the present embodiment is connected to the electrical wiring W13 and the electrical wiring W9. The electrical wiring W9 is connected to the load 27E, and the electrical wiring W13 is connected to the output terminal of the AD / DC converter 33. That is, it can be said that the electrical wiring W19 is a wiring that connects the output terminal of the AD / DC converter 33 and the first load. Also, the semiconductor element of the present embodiment is a MOSFET 47. A diode 45 is connected in parallel to the MOSFET. The cathode terminal of the diode 45 is connected to the electrical wiring W9 that is connected to the output terminal of the first power conversion unit 5 via the electrical wiring W19, and the anode terminal of the diode 45 is connected to the electrical wiring W13 that is the output terminal of the second power conversion unit 7 via the electrical wiring W19. Note that the power transmission circuit 9 may include an electrical wiring that connects the output terminal of the AD / DC converter 33 and the output terminal of the DC / DC converter 23, and a semiconductor element provided on the electrical wiring.

[0025] The control circuit 11A is a circuit that generates a control signal to switch the conduction / non-conduction state of the MOSFET 47 of the power transmission circuit 9 and outputs the control signal to the MOSFET 47. The control circuit 11A also has the function of monitoring the voltage value of the electrical wiring W9 to which the power transmission circuit 9 is connected. When the control circuit 11A detects a drop in the voltage value of the electrical wiring W9 and determines that the supply of DC power from the DC / DC converter 23 to the load 27E has abnormally stopped, it generates and outputs a control signal to switch the MOSFET 47 from non-conduction to conduction. As a result, the output terminal of the AC / DC converter 33 and the load 27E are connected, and the DC power output from the AC / DC converter 33 to the electrical wiring W13 is supplied to the load 27E. In other words, the MOSFET 47 makes the connection between the output terminal of the AC / DC converter 33 and the load 27E conductive when the supply of DC power from the DC / DC converter 23 to the load 27E abnormally stops. In this invention, an abnormal interruption of DC power supply refers to a state in which, for some reason, DC power is not supplied to the first load when it is desired to supply DC power to the first load. Furthermore, when the output voltage of the DC / DC converter 23 drops, the diode 45 conducts between the output terminal of the AC / DC converter 33 and the load 27E. Therefore, DC power is supplied from the AC / DC converter 33 to the load 27E before the MOSFET 47 switches to conduction, and the continuity of the DC power supplied to the load 27E is maintained. The control circuit 11A may monitor the output voltage of the DC / DC converter 23 by detecting the voltage on the electrical wiring W4 or the voltage at the second connection part J69 in the second junction box 25, or it may monitor the output current of the DC / DC converter 23 to determine when the supply of DC power from the DC / DC converter 23 to the load 27E has stopped.

[0026] The control circuit 11B is a circuit that generates control signals to switch the conduction / non-conduction states of the two switches 37 of the power distribution unit 31 and outputs these control signals to each switch 37. The control circuit 11B generates and outputs a control signal to switch the switch 37 of the third connection J71 from conduction to non-conduction when the magnitude of the AC current measured by the ammeter 39 of the third connection J71 exceeds a predetermined threshold. The control circuit 11B also generates and outputs a control signal to switch the switch 37 of the third connection J72 from conduction to non-conduction when the magnitude of the AC current measured by the ammeter 39 of the third connection J72 exceeds a predetermined threshold. The control circuit 11B has the role of preventing overcurrent from being output from the second power conversion unit 7 and thus avoiding power loss at the load.

[0027] Furthermore, the control circuit 11B also has a function to stabilize the power supply to the load 27E, which is of relatively high importance during vehicle operation. Specifically, the control circuit 11B has a function to variably set the threshold value so as to lower the threshold value of the AC current that is the criterion for shutting off the third connection part J72 when the control circuit 11A determines that the supply of DC power from the DC / DC converter 23 to the load 27E has abnormally stopped.

[0028] The power conversion system 1 described above includes a first power conversion unit 5 and a second power conversion unit 7 connected to a battery 15. In the first power conversion unit 5, a load 27E, which is essential for use when the vehicle is running, is connected to the output terminal of a DC / DC converter 23. In the second power conversion unit 7, a load 41A, which is an in-vehicle equipment, is connected to the output terminal of an AC / DC converter 33, which is connected to the battery 15 via an AC inverter 29. Furthermore, the power conversion system 1 is provided with a power transmission circuit 9 between the output terminal of the AC / DC converter 33 and the first load. Due to the function of the power transmission circuit 9, if the supply of DC power to the load 27E is abnormally interrupted, conductivity is maintained between the output terminal of the AC / DC converter 33 and the load 27E. As a result, even if the power supply from the DC / DC converter 23 to the load 27E is interrupted, DC power can be supplied from the AC / DC converter 33 to the load 27E, enabling a stable power supply to the first load, which is essential for use when the vehicle is running.

[0029] In this embodiment, the power transmission circuit 9 includes a diode 45 provided on the electrical wiring W19 as a semiconductor element. With this configuration, in response to a voltage drop at the output terminal of the DC / DC converter 23, the supply of DC power from the output terminal of the AC / DC converter 33 to the load 27E can be started until the MOSFET 47 switches to conduction, enabling a stable power supply without momentary interruptions in the power supply to the load used for vehicle operation.

[0030] Furthermore, in this embodiment, a MOSFET 47 provided on the electrical wiring W19 is included as a semiconductor element in the power transmission circuit 9. With this configuration, DC power can be stably supplied from the output terminal of the AC / DC converter 33 to the load 27E, and power supply to the load used for vehicle operation is achieved with low loss.

[0031] Figure 2 is a circuit diagram showing the power supply path in the power conversion system 1. As shown, if a power loss occurs due to an overcurrent at the output terminal of the DC / DC converter 23 or a failure of the DC / DC converter 23, and the supply of DC power via electrical wiring W4, the second junction box 25, and electrical wiring W9 is abnormally stopped, the voltage of electrical wiring W9 drops. Due to the action of the control circuit 11A, in response to the drop in the voltage of electrical wiring W9, the MOSFET 47 in the power transmission circuit 9 conducts, and DC power output from the AC / DC converter 33 is supplied to the load 27E via the AC / DC converter 33, electrical wiring W13, power transmission circuit 9, and electrical wiring W9.

[0032] Figure 3 is a circuit diagram showing the schematic configuration of a power conversion system 901 according to a comparative example. The difference in the configuration of power conversion system 901 from power conversion system 1 is that it does not have a distribution unit 31, an AC / DC converter 33, a power transmission circuit 9, and control circuits 11A and 11B, and all loads 27A to 27F and 41A are connected to the output terminal of the DC / DC converter 23 by a second junction box 925. In power conversion system 901 with such a configuration, if a power outage occurs between the output terminal of the DC / DC converter 23 and the electrical wiring W9, the supply of DC power to load 27E will stop. In contrast, with power conversion system 1 according to this embodiment, such a situation can be avoided.

[0033] Although various embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and may be modified or applied to other things without changing the gist of each claim.

[0034] The control circuit 11A may be integrated with the second junction box 25, or it may be composed of a circuit section independent of the second junction box 25. Furthermore, the control circuit 11A may be integrated with the DC / DC converter 23, or it may be composed of a circuit section independent of the DC / DC converter 23. Similarly, the control circuit 11B may be integrated with the power distribution unit 31, or it may be composed of a circuit section independent of the power distribution unit 31. Also, the control circuits 11A and 11B may be integrated.

[0035] The control circuit 11B may be omitted. Furthermore, the control circuit 11B does not need to have a function to variably set the threshold value that serves as the criterion for blocking the third connection sections J71 and J72.

[0036] The power transmission circuit 9 includes an electrical wiring W19, a MOSFET 47, and a diode 45, but is not limited to this. It may consist of the electrical wiring W19 and the MOSFET 47, or it may consist of the electrical wiring W19 and a diode provided on the electrical wiring W19, with its anode connected to the output terminal of the AC / DC converter and its cathode connected to the output terminal of the DC / DC converter.

[0037] If the DC power supply from the DC / DC converter 23 to the load 27E is abnormally interrupted, the connection between the AC / DC converter 33 and the load 41A is not disconnected, but it may be disconnected, or the AC power supply from the AC inverter 29 to the AC outlet 43 may be disconnected.

[0038] The electrical wiring W19 only needs to be connected between the output terminal of the AC / DC converter 33 and the output terminal of the DC / DC converter 23. For example, it may be directly connected to the first load, or it may be connected to the output terminal of the DC / DC converter 23. Even when it is connected to the output terminal of the DC / DC converter 23, the output terminal of the DC / DC converter 23 is connected to the load 27E via electrical wiring W4, the second junction box 25, and electrical wiring W9, so it can be said that the electrical wiring W19 is connected between the output terminal of the AC / DC converter 33 and the first load. [Explanation of Symbols]

[0039] 1...Power conversion system, 5...First power conversion unit, 7...Second power conversion unit, 9...Power transmission circuit, 11A,11B...Control circuit, 15...Battery, 23...DC / DC converter, 29...AC inverter, 27A,27B,27C,27D,27E,27F...Load (first load), 33...AC / DC converter, 41A...Load (second load), 43...AC outlet, 45...Diode (semiconductor element), 47...MOSFET (transistor, semiconductor element).

Claims

1. A first power conversion unit connected to a battery, and a second power conversion unit connected to the battery so as to be connected in parallel with the first power conversion unit, The power transmission circuit is connected to the output terminal of the second power conversion unit, The first power conversion unit includes a DC / DC converter that converts the DC power supplied from the battery into a voltage and outputs it, and an auxiliary battery connected to the output terminal of the DC / DC converter. The second power conversion unit includes an inverter that converts the DC power supplied from the battery into AC power and outputs it, and an AC outlet and an AC / DC converter connected to the output terminal of the inverter. A first load, which is essential to make usable when the vehicle is running, is connected to the output terminal of the DC / DC converter. A second load, which is an in-vehicle piece of equipment that is not essential for the vehicle to be driven, is connected to the output terminal of the AC / DC converter. The power transmission circuit includes wiring connecting the output terminal of the AC / DC converter to the first load, and a semiconductor element provided on the wiring, wherein the semiconductor element causes electrical conductivity between the output terminal of the AC / DC converter and the first load when the supply of DC power from the DC / DC converter to the first load is abnormally stopped. Power conversion system.

2. The power conversion system according to claim 1, wherein the semiconductor element is a transistor.

3. The power conversion system according to claim 1, wherein the semiconductor element is a diode whose anode is connected to the output terminal of the AC / DC converter and whose cathode is connected to the output terminal of the DC / DC converter.

4. A switch and an ammeter are further provided, connected in series between the inverter and the AC outlet. The switch is controlled to switch from conducting to non-conducting when the magnitude of the alternating current measured by the ammeter exceeds a predetermined threshold. The predetermined threshold is set to decrease when the supply of DC power from the DC / DC converter to the first load is abnormally interrupted. The power conversion system according to claim 1.

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