Power supply device

Abstract

To drive two kinds of loads having different driving voltages.SOLUTION: The power supply system includes a battery 110 for supplying power to a first power supply line PL1, and a first power converter 120 for converting power outputted from the battery 110 into power of a first voltage V1 and supplying the power to a second power supply line PL2. V1 110, the power supply system includes the second power converter 130 that supplies power to the second power supply line PL2, and the control device 140 that controls the first power converter 120 and the second power converter 130, and the control device 140 turns on the first power converter 120 and turns off the second power converter 130 in the first period, and turns off the first power converter 120 and turns on the second power converter 130 in the period other than the first period.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, vehicles have been equipped with a low-voltage battery that outputs low-voltage power to supply low-voltage power to an ECU that controls electrical components of the vehicle. In addition to this low-voltage battery, electric vehicles (BEVs (Battery Electric Vehicles)), hybrid vehicles (HEVs (Hybrid Electric Vehicles), and PHEVs (Plug-in Hybrid Electric Vehicles)) are equipped with a high-voltage battery that outputs high-voltage power to supply high-voltage power to a motor that drives the vehicle (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-124060 Summary of the Invention [Problem to be solved by the invention]

[0004] In electric vehicles, the installation of a low-voltage battery in addition to a high-voltage battery has resulted in increased costs and weight. Furthermore, lead-acid batteries used as low-voltage batteries have a lifespan of about three years, so installing a low-voltage battery in an electric vehicle also increases costs in this respect.

[0005] An object of the present invention is to drive two types of loads with different drive voltages. [Means for solving the problem]

[0006] In order to solve the above problem, a power supply device according to an embodiment of the present invention includes a battery that supplies power to a first power supply line, a first power converter that converts the output power of the battery into power of a first voltage value and supplies it to a second power supply line, a second power converter that converts the output power of the battery into power of the first voltage value and supplies it to the second power supply line, and a control device that controls the first power converter and the second power converter, wherein the control device turns on the first power converter and turns off the second power converter during a first period, and turns on the first power converter and turns off the second power converter during periods other than the first period. [Effects of the Invention]

[0007] According to the present invention, it is possible to drive two types of loads with different drive voltages. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing a power supply device 100 according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram showing an example of processing operations executed by control device 140 of power supply device 100 according to the present embodiment when switching from the second period to the first period (when the ignition switch of the vehicle switches from off to on). [Figure 3] FIG. 10 is a diagram showing an example of processing operations executed by control device 140 of power supply device 100 according to the present embodiment when switching from a first period to a second period (when the ignition switch of the vehicle switches from on to off). [Figure 4] FIG. 10 is a diagram illustrating another example of the power supply device 100. [Figure 5] FIG. 2 is a diagram illustrating an example of a control device 140. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Power supply device 100> 1 is a diagram showing a power supply device 100 according to one embodiment of the present invention. The power supply device 100 includes a battery 110, a first power converter 120, a second power converter 130, and a control device 140. The power supply device 100 supplies power to a first load L1 driven by an output voltage VB (e.g., 200 V or higher) of the battery 110 via a first power supply line PL1, and supplies power to a second load L2 and a third load L3 driven by a voltage (e.g., 12 V) lower than the output voltage VB of the battery 110 via a second power supply line PL2.

[0010] The battery 110 supplies power having a battery output voltage value VB to a first power supply line PL1. The battery 110 is, for example, configured with a plurality of cells 111 connected in series, and is, for example, a lithium-ion battery. A first load L1 driven by the output voltage VB of the battery 110 is connected to the first power supply line PL1, and the output power of the battery 110 is supplied to the first load L1 via the first power supply line PL1. Although one first load L1 is shown in FIG. 1, the number of first loads L1 may be two or more.

[0011] The first power converter 120 converts the output power of the battery 110 into power of a first voltage value V1 (e.g., 12 V) and supplies the power of the first voltage value V1 to the second power supply line PL2. In other words, the first power converter 120 converts the voltage value of the power output from the battery 110 from the output voltage value VB of the battery 110 to the first voltage value V1, and then supplies the power to the second power supply line PL2.

[0012] The first power converter 120 is, for example, a DC / DC converter (for example, an isolated DC / DC converter) and has a first power input terminal PI11, a second power input terminal PI12, a first power output terminal PO11, and a second power output terminal PO12. The first power input terminal PI11 is connected to the positive electrode of the battery 110, and the second power input terminal PI12 is connected to the negative electrode. Power having an output voltage value VB of the battery 110 is input to the first power converter 120 from the first power input terminal PI11 and the second power input terminal PI12. The first power converter 120 then outputs power having a first voltage value V1 from the first power output terminal PO11 and the second power output terminal PO12. In the example shown in FIG. 1, the first power output terminal PO11 is connected to the second power supply line PL2, the second power output terminal PO12 is grounded, and the power output from the first power converter 120 is supplied to a load connected to the second power supply line PL2.

[0013] The first power converter 120 has a control unit 121 that controls the operation of the first power converter 120. The control unit 121 is configured by, for example, a computer. The control unit 121 has a control signal input terminal CI1, and controls the on / off of the first power converter 120 based on a signal input to this control signal input terminal CI1. In other words, the control unit 121 of the first power converter 120 switches the state of the first power converter 120 between a state in which power is supplied to the second power supply line PL2 (on state) and a state in which power is not supplied to the second power supply line PL2 (off state) based on the signal input to the control signal input terminal CI1.

[0014] The second power converter 130 converts the output power of the battery 110 into power of a first voltage value V1 and supplies the power of the first voltage value V1 to the second power supply line PL2. In other words, the second power converter 130 converts the voltage value of the power output from the battery 110 from the output voltage value VB of the battery 110 to the first voltage value V1, and then supplies the power to the second power supply line PL2.

[0015] The second power converter 130 is, for example, a DC / DC converter (for example, an isolated DC / DC converter) and has a first power input terminal PI21, a second power input terminal PI22, a first power output terminal PO21, and a second power output terminal PO22. The first power input terminal PI21 is connected to the positive electrode of the battery 110, and the second power input terminal PI22 is connected to the negative electrode. Power having an output voltage value VB of the battery 110 is input to the first power input terminal PI21 and the second power input terminal PI22 of the second power converter 130. The second power converter 130 outputs power having a first voltage value V1 from the first power output terminal PO21 and the second power output terminal PO22. In the example shown in FIG. 1, the first power output terminal PO21 is connected to the second power supply line PL2, the second power output terminal PO22 is grounded, and the power output from the second power converter 130 is supplied to a load connected to the second power supply line PL2.

[0016] The second power converter 130 has a control unit 131 that controls the operation of the second power converter 130. The control unit 131 is configured by, for example, a computer. The control unit 131 has a control signal input terminal CI2, and controls the on / off of the second power converter 130 based on a signal input to this control signal input terminal CI2. In other words, the control unit 131 of the second power converter 130 switches the state of the second power converter 130 between a state in which power is supplied to the second power supply line PL2 (on state) and a state in which power is not supplied to the second power supply line PL2 (off state) based on the signal input to the control signal input terminal CI2.

[0017] The control device 140 controls the on / off of the first power converter 120 and the on / off of the second power converter 130. The control device 140 has a first control signal output terminal CO1 connected to a control signal input terminal CI1 of the control unit 121 of the first power converter 120 and a second control signal output terminal CO2 connected to a control signal input terminal CI2 of the control unit 131 of the second power converter 130. The control device 140 controls the on / off of the first power converter 120 by outputting a control signal from the first control signal output terminal CO1 and inputting it to the control signal input terminal CI1 of the control unit 121 of the first power converter 120. The control device 140 controls the on / off of the second power converter 130 by outputting a control signal from the second control signal output terminal CO2 and inputting it to the control signal input terminal CI2 of the control unit 131 of the second power converter 130.

[0018] In this embodiment, a second load L2 and a third load L3 are connected to a second power supply line PL2 to which power of a first voltage V1 is supplied. The first voltage V1 is a voltage value capable of driving the second load L2 and the third load L3. The output voltage VB of the battery 110 is not a voltage value capable of driving the second load L2 and the third load L3, but is, for example, a voltage value greater than the first voltage V1 and greater than a voltage value capable of driving the second load L2 and the third load L3. The second load L2 is a load that is on during a first period and off during a period other than the first period (a second period), and the third load L3 is a load that is always on. While FIG. 1 shows one second load L2 and one third load L3, the number of second loads L2 and third loads L3 may be two or more.

[0019] That is, in this embodiment, in the first period, the power supplied to the second power supply line PL2 is consumed by both the second load L2 and the third load L3, but in the second period, the power supplied to the second power supply line PL2 is consumed by the third load L3 but not by the second load L2. Therefore, in this embodiment, the power consumption in the second period is smaller than the power consumption in the first period.

[0020] Therefore, in this embodiment, the second power converter 130 is a power converter whose output power value is smaller than that of the first power converter 120, and the control device 140 turns on the first power converter 120 and turns off the second power converter 130 during a first period, and turns off the first power converter 120 and turns on the second power converter 130 during a second period (a period other than the first period). In other words, in this embodiment, during a first period when both the second load L2 and the third load L3 are on, the power of the battery 110 is converted from the output voltage value VB of the battery 110 to a first voltage value V1 using the first power converter 120, and during a second period when the second load is off and the third load L3 is on, the power of the battery 110 is converted from the output voltage value VB of the battery 110 to a first voltage value V1 using the second power converter 130, whose outputtable power value is smaller than that of the first power converter 120.

[0021] In this case, for example, the maximum output power value of the second power converter 130 may be set to be smaller than the maximum output power value of the first power converter 120. Also, the rated current value of the second power converter may be set to be smaller than the rated current value of the first power converter 120. In this case, the maximum output power value and rated current value of the first power converter 120 may be set based on the power consumption value in the first period, and the maximum output power value and rated current value of the second power converter 130 may be set based on the power consumption value in the second period. For example, the maximum output power value and rated current value of the first power converter 120 may be set to improve conversion efficiency when supplying power of the power consumption value in the first period, and the maximum output power value and rated current value of the second power converter 130 may be set to improve conversion efficiency when supplying power of the power consumption value in the second period.

[0022] As described above, in this embodiment, the battery 110 that supplies power to the first load L1 also supplies power to the second load L2 and the third load L3, which have a different drive voltage from the first load L1. Therefore, in this embodiment, there is no need to add a battery for supplying power with a drive voltage to the second load L2 and the third load L3, and it is possible to supply power to the second load L2 and the third load L3 in addition to the first load L1 using the battery 110. In other words, in this embodiment, it is possible to drive two types of loads with different drive voltages using a low-cost, lightweight configuration.

[0023] Furthermore, in this embodiment, the first power converter 120, which can output a large amount of power, is used only in the first period when power consumption is large, and the second power converter 130, which can output a small amount of power, is used in the second period when power consumption is small. Therefore, in this embodiment, the output power of the battery 110 can be supplied to a load (the second load L2 or the third load L3) whose drive voltage value is lower than the output voltage value VB of the battery 110 without reducing the conversion efficiency.

[0024] The power supply device 100 is, for example, a power supply device for a vehicle (e.g., an electric vehicle (Battery Electric Vehicle)), the first load L1 is, for example, a drive motor of the vehicle, and the second load L2 and the third load L3 are, for example, an ECU of the vehicle. In particular, the second load L2 is a load that is on when the ignition switch of the vehicle is on and is off when the ignition switch of the vehicle is off, and the third load L3 is a load that is always on regardless of the state of the ignition switch of the vehicle. In other words, the first period is a period during which the ignition switch is on, and the second period is a period during which the ignition switch is off.

[0025] In this case, the control device 140 has a means for checking the state of the ignition switch. When the ignition switch is switched from off to on, the control device 140 controls the second power converter 130 to be off and the first power converter 120 to be on, and when the ignition switch is switched from on to off, the control device 140 controls the first power converter 120 to be off and the second power converter 130 to be on.

[0026] In this way, the power consumption (so-called dark current) when the ignition switch of the vehicle is off can be supplied from the battery 110 without reducing the conversion efficiency.

[0027] 2 is a diagram showing an example of processing operations executed by the control device 140 of the power supply device 100 according to this embodiment when switching from the second period to the first period (when the ignition switch of the vehicle switches from off to on). The control device 140 turns off the second power converter 130 (step S201). The control device 140 turns on the first power converter 120 (step S202).

[0028] 3 is a diagram showing an example of processing operations executed by the control device 140 of the power supply device 100 according to this embodiment when switching from the first period to the second period (when the ignition switch of the vehicle switches from on to off). The control device 140 turns off the first power converter 120 (step S301). The control device 140 turns on the second power converter 130 (step S302).

[0029] <Third Power Converter 150> The control unit 121 of the first power converter 120 has a power input terminal CP1 for receiving a supply of power, the control unit 131 of the second power converter 130 has a power input terminal CP2 for receiving a supply of power, and the control device 140 has a power input terminal CP3 for receiving a supply of power. The power input terminal CP1 of the control unit 121 of the first power converter 120, the power input terminal CP2 of the control unit 131 of the second power converter 130, and the power input terminal CP3 of the control device 140 are preferably connected to a second power supply line PL2, as shown in FIG. 1 . This makes it possible to supply power to the control unit 121 of the first power converter 120, the control unit 131 of the second power converter 130, and the control device 140 via the second power supply line PL2, and makes it possible to supply power of a voltage value lower than the output voltage value of the battery 110 to the control unit 121 of the first power converter 120, the control unit 131 of the second power converter 130, and the control device 140.

[0030] When the first power converter 120 and the second power converter 130 are switched from an off state to an on state, the timing at which the first power converter 120 and the second power converter 130 start supplying power to the second power supply line PL2 may be delayed from the timing at which the switching from the off state to the on state is executed. In other words, when the first power converter 120 and the second power converter 130 are switched from an off state to an on state, there may be a moment when power is not supplied to the second power supply line PL2 from either the first power converter 120 or the second power converter 130. If there is a moment when power is not supplied to the second power supply line PL2, at this moment, power is not supplied to the loads connected to the second power supply line PL2 (the second load L2, the third load L3, the control unit 121 of the first power converter 120, the control unit 131 of the second power converter 130, and the control device 140). Furthermore, at this moment, power is not supplied to the control unit 121 of the first power converter 120, the control unit 131 of the second power converter 130, and the control device 140, so there is a possibility that the first power converter 120 and the second power converter 130 will not be switched from the off state to the on state normally.

[0031] Therefore, as shown in FIG. 4, the power supply device 100 may further include a third power converter 150. The third power converter 150 converts the output power of the battery 110 into power with a second voltage value V2 (for example, 10V) and supplies the power with the first voltage value V1 to the second power supply line PL2. That is, the third power converter 150 converts the voltage value of the power output from the battery 110 to the second voltage value V2 and then supplies it to the second power supply line PL2. The third power converter 150 is, for example, always in an on state.

[0032] The third power converter 150 is, for example, a DC / DC converter (for example, an isolated DC / DC converter), and includes a first power input terminal PI31, a second power input terminal PI32, a first power output terminal PO31, and a second power output terminal PO32.

[0033] The first power input terminal PI31 may be connected to the positive electrode of the battery 110, and the second power input terminal PI32 may be connected to the negative electrode of the battery 110. Alternatively, as shown in FIG. 4, the first power input terminal PI31 may be connected to the positive electrode of a sub-battery 112 (in the example shown in FIG. 4, a battery composed of some cells 111 on the negative electrode side of the battery 110) composed of some cells 111 of the battery 110, and the second power input terminal PI32 may be connected to the negative electrode of the sub-battery 112. When the first power input terminal PI31 is connected to the positive electrode of the battery 110 and the second power input terminal PI32 is connected to the negative electrode of the battery 110, the power with the output voltage value VB of the battery 110 is input to the third power converter 150 from the first power input terminal PI31 and the second power input terminal PI32. When the first power input terminal PI31 is connected to the positive electrode of the sub-battery 112 and the second power input terminal PI32 is connected to the negative electrode of the sub-battery 112, the power with the output voltage value VSB (<VB) of the sub-battery 112 is input to the third power converter 150 from the first power input terminal PI31 and the second power input terminal PI32.

[0034] The third power converter 150 outputs power of a second voltage value V2 from a first power output terminal PO31 and a second power output terminal PO32. In the example shown in Fig. 4, the first power output terminal PO31 is connected to a second power supply line PL2, the second power output terminal PO32 is grounded, and the power output from the third power converter 150 is supplied to a load connected to the second power supply line PL2.

[0035] By doing this, even if there is a period in which power is not supplied to the second power supply line PL2 from either the first power converter 120 or the second power converter 130, power will be supplied to the second power supply line PL2 from the third power converter 150, making it possible to constantly supply power to the loads connected to the second power supply line PL (the second load L2, the third load L3, the control unit 121 of the first power converter 120, the control unit 131 of the second power converter 130, and the control device 140).

[0036] At this time, the second voltage value V2 is set to be smaller than the first voltage value V1, the first power output terminal PO31 of the third power converter 150 is connected to the second power supply line PL2 via the first diode D1, and the forward direction of the first diode D1 is set to be from the first power output terminal PO31 of the third power converter 150 to the second power supply line PL2.

[0037] In this way, power is supplied from the third power converter 150 to the second power supply line PL2 only during periods when power is not being supplied to the second power supply line PL2 from either the first power converter 120 or the second power converter 130. When power is being supplied to the second power supply line PL2 from either the first power converter 120 or the second power converter 130, power is not supplied to the second power supply line PL2 from the third power converter 150. As a result, even if the third power converter 150 is always in an on state, the third power converter 150 supplies power to the second power supply line PL2 only when it is necessary for the third power converter 150 to supply power to the second power supply line PL2.

[0038] <Control device 140> The control device 140 may be configured by a computer, or may have a control section 141 configured by a computer, a mechanical relay 142, and a NOT circuit 143, as shown in FIG.

[0039] The control unit 141 has a power input terminal CP31 and a control signal output terminal CO11. The power input terminal CP31 is connected to a second power supply line PL2, and the control unit 141 receives power from the second power supply line PL2. The control unit 141 outputs a control signal from the control signal output terminal CO11.

[0040] The switch of the mechanical relay 142 is connected between the second power supply line PL2 and a control signal input terminal CI1 of the control unit 121 of the first power converter 120, and the coil of the mechanical relay 142 is connected between the control signal output terminal CO11 of the control unit 141 and ground. The input terminal of the NOT circuit 143 is connected to the control signal output terminal CO11 of the control unit 141, and the output terminal of the NOT circuit 143 is connected to the control signal input terminal CI2 of the control unit 131 of the second power converter 130.

[0041] Therefore, when the control unit 141 outputs a high-level signal from the control signal output terminal CO11, the switch of the mechanical relay 142 is turned on, the first control signal output terminal CO1 of the control device 140 is connected to the second power supply line PL2, a high-level signal is input to the input terminal of the NOT circuit 143, and a low-level signal is output from the output terminal of the NOT circuit 143. As a result, when the control unit 141 outputs a high-level signal from the control signal output terminal CO11, a high-level signal (a signal of the first voltage value V1 or the second voltage value V2) is input to the control signal input terminal CI1 of the control unit 121 of the first power converter 120, and a low-level signal is input to the control signal input terminal CI2 of the control unit 121 of the second power converter 130.

[0042] On the other hand, when the control unit 141 outputs a low-level signal (0 V signal) from the control signal output terminal CO11, the switch of the mechanical relay 142 is turned off, the control signal input terminal CI1 of the control unit 121 of the first power converter 120 is separated from the second power supply line PL2, a low-level signal is input to the input terminal of the NOT circuit 143, and a high-level signal is output from the output terminal of the NOT circuit 143. As a result, when the control unit 141 outputs a low-level signal (0 V signal) from the control signal output terminal CO11, a low-level signal (0 V signal) is input to the control signal input terminal CI1 of the control unit 121 of the first power converter 120, and a high-level signal is input to the control signal input terminal CI2 of the control unit 131 of the second power converter 130.

[0043] Therefore, it is preferable that the control unit 141 outputs a High-level signal from the control signal output terminal CO11 during the first period, and outputs a Low-level signal (a 0 V signal) from the control signal output terminal CO11 during periods other than the first period. At this time, it is preferable that the control unit 121 of the first power converter 120 turns on the first power converter 120 when a High-level signal is input to the control signal input terminal CI1, and turns off the first power converter 120 when a Low-level signal is input to the control signal input terminal CI1, and the control unit 131 of the second power converter 130 turns on the second power converter 130 when a High-level signal is input to the control signal input terminal CI2, and turns off the second power converter 130 when a Low-level signal is input to the control signal input terminal CI2.

[0044] By doing this, the control device 140 can control the first power converter 120 to be on and the second power converter 130 to be off during the first period, and can control the first power converter 120 to be off and the second power converter 130 to be on during the second period (a period other than the first period).

[0045] Alternatively, the control unit 141 may output a low-level (0 V signal) signal from the control signal output terminal CO11 during the first period, and output a high-level signal from the control signal output terminal CO11 during periods other than the first period. In this case, the control unit 121 of the first power converter 120 may turn on the first power converter 120 when a low-level signal is input to the control signal input terminal CI1, and may turn off the first power converter 120 when a high-level signal is input to the control signal input terminal CI1. The control unit 131 of the second power converter 130 may turn on the second power converter 130 when a low-level signal is input to the control signal input terminal CI2, and may turn off the second power converter 130 when a high-level signal is input to the control signal input terminal CI2.

[0046] By doing this, the control device 140 can control the first power converter 120 to be on and the second power converter 130 to be off during the first period, and can control the first power converter 120 to be off and the second power converter 130 to be on during the second period (a period other than the first period).

[0047] The present invention has been described above in terms of preferred embodiments thereof. While the present invention has been described herein with reference to specific examples, various modifications and variations can be made to these examples without departing from the spirit and scope of the present invention as set forth in the claims. [Explanation of symbols]

[0048] 100 Power supply 110 Battery 111 cells 112 Sub-battery 120 first power converter 121 Control Unit 130 Second power converter 131 Control Unit 140 Control device 141 Control Unit 142 Mechanical Relay 143 NOT circuits

Claims

1. a battery that supplies power to the first power supply line; a first power converter that converts the output power of the battery into power of a first voltage value and supplies the power to a second power supply line; a second power converter that converts the output power of the battery into power of the first voltage value and supplies the power to the second power supply line; a control device that controls the first power converter and the second power converter, The control device during a first time period, turning on the first power converter and turning off the second power converter; The power supply device turns off the first power converter and turns on the second power converter during a period other than a first period.

2. the second power supply line is connected to a second load and a third load; The second load is is on during the first period, The power supply is off during periods other than the first period, 2. The power supply of claim 1, wherein the third load is always on.

3. the power supply device is a power supply device for a vehicle, the first period is a period during which an ignition switch of the vehicle is on, The power supply device according to claim 1 , wherein the period other than the first period is a period during which an ignition switch of the vehicle is off.

4. 4. The power supply device according to claim 2, wherein a value of power that the second power converter can output is smaller than a value of power that the first power converter can output.

5. 5. The power supply device according to claim 4, further comprising a third power converter that converts the output power of the battery into power of a second voltage value and outputs the power to the second power supply line.

6. a first diode connected between the second power supply line and the third power converter; the second voltage value is lower than the first voltage value; 6. The power supply device according to claim 5, wherein the forward direction of the first diode is from the third power converter to the second power supply line.

7. the first power converter has a control unit that controls an operation of the first power converter; a control unit of the first power converter having a power input terminal for receiving a supply of power; the second power converter has a control unit that controls an operation of the second power converter, a control unit of the second power converter having a power input terminal for receiving a supply of power; the control device has a power input terminal for receiving a supply of power, 7. The power supply device according to claim 6, wherein a power input terminal of a control unit of the first power converter, a power input terminal of a control unit of the second power converter, and a power input terminal of the control device are connected to the second power supply line.

8. the battery has a plurality of cells; 7. The power supply device according to claim 6, wherein the third power converter converts output power of a sub-battery formed by some of the cells of the battery into power of the second voltage value and outputs the power to the second power supply line.

9. the first power converter has a control unit that controls an operation of the first power converter; The control unit of the first power converter a control signal input terminal to which a control signal is input; controlling on / off of the first power converter based on a control signal input to a control signal input terminal of a control unit of the first power converter; the second power converter has a control unit that controls an operation of the second power converter, The control unit of the second power converter a control signal input terminal to which a control signal is input; 5. The power supply device according to claim 4, wherein the second power converter is controlled to be turned on and off based on a control signal input to a control signal input terminal of a control unit of the second power converter.

10. the control device includes a control unit, a mechanical relay, and a NOT circuit; the control unit of the control device has a control signal output terminal for outputting a control signal, a switch of the mechanical relay connected between the second power supply line and a control signal input terminal of a control unit of the first power converter; a coil of the mechanical relay connected between a control signal output terminal of a control unit of the control device and ground; an input terminal of the NOT circuit is connected to a control signal output terminal of a control unit of the control device; 10. The power supply device according to claim 9, wherein an output terminal of the NOT circuit is connected to a control signal input terminal of a control unit of the second power converter.

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