Power supply system

Abstract

The present invention provides a power supply system comprising: a first DC power supply having a positive terminal connected to a first node; a second DC power supply having a negative terminal connected to a second node; a first contactor connected between the first node and a third node; a second contactor connected between the second node and a fourth node; a third contactor connected between the negative terminal of the first DC power supply and a fifth node; a fourth contactor connected between the positive terminal of the second DC power supply and a sixth node; a first switch connected between the third node and the sixth node; a second switch connected between the fifth node and the sixth node; a third switch connected between the fourth node and the fifth node; a first voltage conversion circuit connected between the first node and the fourth node; and a second voltage conversion circuit connected between the second node and the third node.

Description

Technical Field

[0001] This invention relates to power supply systems. Background Technology

[0002] Japanese Patent Application Publication No. 2014-003858 discloses a power supply device that switches between a series connection of a first power supply, a second power supply, and a reactor connected in series with an inverter, and a parallel connection of the first power supply, the second power supply, and the inverter connected in parallel. Summary of the Invention

[0003] The following structure is not described in Japanese Patent Application Publication No. 2014-003858: This structure is used to continuously supply power from the power supply unit in the event of a failure of the load device that is supplied with power from the power supply unit.

[0004] The power supply system of the first aspect of the present invention comprises: a first DC power supply having a positive terminal connected to a first node; a second DC power supply having a negative terminal connected to a second node; a first contactor connected between the first node and a third node; a second contactor connected between the second node and a fourth node; a third contactor connected between the negative terminal of the first DC power supply and a fifth node; a fourth contactor connected between the positive terminal of the second DC power supply and a sixth node; a first switch connected between the third node and the sixth node; a second switch connected between the fifth node and the sixth node; a third switch connected between the fourth node and the fifth node; a first voltage conversion circuit connected between the first node and the fourth node; and a second voltage conversion circuit connected between the second node and the third node.

[0005] The second solution, based on the power supply system of the first solution, may further include: a fourth switch connected between the output terminal of the first voltage conversion circuit and the seventh node; and a fifth switch connected between the output terminal of the second voltage conversion circuit and the seventh node.

[0006] The third option, based on the power supply system of the first option, may also include a fifth contactor connected between the first node and the first voltage conversion circuit, wherein the rating of the fifth contactor is smaller than that of the first contactor.

[0007] The fourth option, based on the power supply system of the first option, may also include a sixth contactor connected between the second node and the second voltage conversion circuit, wherein the rating of the sixth contactor is smaller than that of the second contactor.

[0008] The fifth option, based on the power system of the first option, may also include a control device. When the control device detects a fault in the first load device connected between the third node and the fourth node, it controls the first contactor, the second contactor, and the fourth contactor to be in an open state, controls the third contactor to be in an on state, controls the first switch and the third switch to be in an on state, and controls the second switch to be in an open state.

[0009] The sixth solution, based on the power system of the first solution, may also include a control device. When the control device detects a fault in the first load device connected between the third node and the fourth node, it controls the first contactor, the second contactor, and the third contactor to be in an open state, controls the fourth contactor to be in an on state, controls the first switch and the third switch to be in an on state, and controls the second switch to be in an open state.

[0010] The seventh option, based on the power supply system of the first option, may also include a control device. When the control device detects a fault in the first load device connected between the third node and the fourth node, it controls the first contactor and the second contactor to be in an open state, controls the third contactor and the fourth contactor to be in an on state, controls the first switch and the third switch to be in an on state, and controls the second switch to be in an open state.

[0011] According to the first scheme, even if a fault such as overcurrent occurs in the first load device connected between the third node N3 and the fourth node N4, at least one of the first voltage conversion circuit and the second voltage conversion circuit can continue to operate, thus maintaining a continuous power supply from the power supply system.

[0012] According to the second scheme, even if either the first voltage conversion circuit or the second voltage conversion circuit fails, power can still be continuously supplied to a second load device, for example, connected to the seventh node.

[0013] According to the third scheme, the wiring connecting the first node and the first voltage conversion circuit is dedicated to the power supply of the control device. Therefore, the rating of the fifth contactor installed on this wiring can be set to be lower than that of the contactor used for large power loads such as motors. As a result, the power supply system can be miniaturized and its cost reduced.

[0014] According to the fourth scheme, the wiring connecting the second node and the second voltage conversion circuit is dedicated to the power supply of the control device. Therefore, the rating of the sixth contactor installed on this wiring can be set to be lower than that of contactors used for large power loads such as motors. This enables the miniaturization and cost reduction of the power supply system.

[0015] According to the fifth scheme, even if a fault such as overcurrent occurs in the first load device connected between the third node and the fourth node, the first voltage conversion circuit can continue to operate while the first DC power supply and the second DC power supply are electrically disconnected from the first load device.

[0016] According to the sixth scheme, even if a fault such as overcurrent occurs in the first load device connected between the third node and the fourth node, the second voltage conversion circuit can continue to operate while the first DC power supply and the second DC power supply are electrically disconnected from the first load device.

[0017] According to the seventh scheme, even if a fault such as overcurrent occurs in the first load device connected between the third node and the fourth node, the first DC power supply and the second DC power supply can be electrically disconnected from the first load device while both the first voltage conversion circuit and the second voltage conversion circuit continue to operate. Attached Figure Description

[0018] Figure 1 This is a diagram showing the outline structure of the power supply system according to an embodiment.

[0019] Figure 2 This is a diagram showing the state of each switch and each contactor when the power supply system of the embodiment operates in series mode.

[0020] Figure 3 This is a diagram showing the state of each switch and each contactor when the power supply system of the embodiment operates in parallel mode.

[0021] Figure 4A This is a diagram showing the current path when the power supply system of the embodiment operates in heating mode.

[0022] Figure 4B This is a diagram showing the current path when the power supply system of the embodiment operates in heating mode.

[0023] Figure 4C This is a diagram showing the current path when the power supply system of the embodiment operates in heating mode.

[0024] Figure 5 This is a graph showing the current changes when the power supply system of the embodiment operates in heating mode.

[0025] Figure 6 This is a graph showing the relationship between the amplitude and ratio (T / Tf) of the current flowing when the power system in the embodiment is operating in heating mode.

[0026] Figure 7A This is a diagram showing the current path when the power supply system of the embodiment operates in the first voltage balance mode.

[0027] Figure 7B This is a diagram showing the current path when the power supply system of the embodiment operates in the first voltage balance mode.

[0028] Figure 8 This is a graph showing the current changes when the power supply system of the embodiment operates in the first voltage balance mode.

[0029] Figure 9A This is a diagram showing the current path when the power supply system of the embodiment operates in the second voltage balance mode.

[0030] Figure 9B This is a diagram showing the current path when the power supply system of the embodiment operates in the second voltage balance mode.

[0031] Figure 10 This is a diagram showing the current changes when the power supply system of the embodiment operates in the second voltage balance mode.

[0032] Figure 11 This is a flowchart illustrating the process of voltage balance control in the power supply system of the embodiment.

[0033] Figure 12 This is a first diagram showing the state of each switch and each contactor when the power system of the embodiment is operating in fault protection mode.

[0034] Figure 13 This is a second diagram showing the state of each switch and each contactor when the power system of the embodiment operates in fault protection mode.

[0035] Figure 14 This is the third diagram showing the state of each switch and each contactor when the power system of the embodiment operates in fault protection mode. Detailed Implementation

[0036] Hereinafter, an embodiment of the power supply system of the present invention will be described with reference to the accompanying drawings.

[0037] <Power System>

[0038] Figure 1 This is a diagram showing the outline structure of the power supply system 1 according to this embodiment. (As shown...) Figure 1 As shown, the power supply system 1 includes a power supply unit 10, a power switching circuit 20, a voltage conversion unit 30, a fifth contactor 41, a sixth contactor 42, and a control device 50.

[0039] For example, power system 1 is installed in an electric vehicle to supply DC power to multiple devices within the electric vehicle.

[0040] The power supply unit 10 includes a first DC power supply 11, a second DC power supply 12, a first contactor 13, a second contactor 14, a third contactor 15, a fourth contactor 16, a first voltage sensor 17, and a second voltage sensor 18. The first DC power supply 11 and the second DC power supply 12 are rechargeable secondary batteries such as storage batteries.

[0041] The first DC power supply 11 has a positive terminal electrically connected to the first node N1 and a negative terminal electrically connected to one end of the third contactor 15. The second DC power supply 12 has a positive terminal electrically connected to one end of the fourth contactor 16 and a negative terminal electrically connected to the second node N2.

[0042] The first contactor 13 is electrically connected between the first node N1 and the third node N3. The second contactor 14 is electrically connected between the second node N2 and the fourth node N4. The third contactor 15 is connected between the negative terminal of the first DC power supply 11 and the fifth node N5. The fourth contactor 16 is connected between the positive terminal of the second DC power supply 12 and the sixth node N6.

[0043] The contactors included in the power supply unit 10 are electrically connected to the control device 50, and for this purpose... Figure 1 The diagram is omitted. The states of each contactor included in the power supply unit 10 are switched between the on and off states by the control device 50.

[0044] The first voltage sensor 17 detects the voltage Vs1 of the first DC power supply 11 and outputs a signal indicating its detection result to the control device 50. The second voltage sensor 18 detects the voltage Vs2 of the second DC power supply 12 and outputs a signal indicating its detection result to the control device 50.

[0045] The power switching circuit 20 includes a first switch SW1, a second switch SW2, a third switch SW3, a first reactor 21, a second reactor 22, and a smoothing capacitor 23. For example, the first switch SW1, the second switch SW2, and the third switch SW3 are n-channel MOS-FETs (Metal-Oxide-Semiconductor Field-Effect Transistors).

[0046] The first switch SW1 is electrically connected between the third node N3 and the sixth node N6. Specifically, the first switch SW1 has a drain terminal electrically connected to the third node N3 and a source terminal electrically connected to the sixth node N6.

[0047] The second switch SW2 is electrically connected between the fifth node N5 and the sixth node N6. Specifically, the second switch SW2 has a drain terminal electrically connected to the sixth node N6 and a source terminal electrically connected to the fifth node N5.

[0048] The third switch SW3 is electrically connected between the fourth node N4 and the fifth node N5. Specifically, the third switch SW3 has a drain terminal electrically connected to the fifth node N5 and a source terminal electrically connected to the fourth node N4.

[0049] The gate terminals of each switch in the power switching circuit 20 are electrically connected to the control device 50, and this is reflected in... Figure 1 The diagram is omitted. As will be described later, pulse width modulated pulse signals, i.e., gate signals, are supplied from the control device 50 to the gate terminals of each switch included in the power switching circuit 20.

[0050] The first reactor 21 is electrically connected between the third contactor 15 and the fifth node N5. The second reactor 22 is electrically connected between the fourth contactor 16 and the sixth node N6. The smoothing capacitor 23 is electrically connected between the third node N3 and the fourth node N4. The potential difference between the third node N3 and the fourth node N4 is the output voltage Vo of the power switching circuit 20.

[0051] The voltage conversion unit 30 includes a first voltage conversion circuit 31, a second voltage conversion circuit 32, a fourth switch 33, and a fifth switch 34. For example, the first voltage conversion circuit 31 and the second voltage conversion circuit 32 are DC / DC converters.

[0052] The first voltage conversion circuit 31 is electrically connected between the first node N1 and the fourth node N4. The second voltage conversion circuit 32 is electrically connected between the second node N2 and the third node N3. That is, when all the contactors in the power supply unit 10 are in the ON state, the output voltage Vo of the power switching circuit 20 is input to both the first voltage conversion circuit 31 and the second voltage conversion circuit 32. The first voltage conversion circuit 31 and the second voltage conversion circuit 32 output DC voltages with voltage values ​​different from the input voltages.

[0053] The fourth switch 33 is electrically connected between the output terminal of the first voltage conversion circuit 31 and the seventh node N7. The fifth switch 34 is electrically connected between the output terminal of the second voltage conversion circuit 32 and the seventh node N7. Each switch included in the voltage conversion unit 30 is electrically connected to the control device 50, and this is indicated in... Figure 1 Illustrations omitted. The states of the switches included in the voltage conversion unit 30 are switched between on and off states by the control device 50.

[0054] The fifth contactor 41 is electrically connected between the first node N1 and the first voltage conversion circuit 31. The rating of the fifth contactor 41 may also be smaller than the rating of the first contactor 13. The sixth contactor 42 is electrically connected between the second node N2 and the second voltage conversion circuit 32.

[0055] The rating of the sixth contactor 42 is smaller than that of the second contactor 14. The fifth contactor 41 and the sixth contactor 42 are electrically connected to the control device 50, for which... Figure 1 Illustrations omitted. The states of the fifth contactor 41 and the sixth contactor 42 are switched between the on and off states by the control device 50.

[0056] The control device 50 controls the switches included in the power switching circuit 20 based on the output signals of the first voltage sensor 17 and the second voltage sensor 18. In addition, the control device 50 controls the contactors included in the power supply unit 10, the switches included in the voltage conversion unit 30, the fifth contactor 41, and the sixth contactor 42.

[0057] For example, the power supply system 1 configured as described above supplies DC power to the first load device 100 and the second load device 200, respectively. The first load device 100 is electrically connected between the third node N3 and the fourth node N4. That is, the output voltage Vo of the power switching circuit 20 is input to the first load device 100. For example, the first load device 100 is an E-Axle or an electric compressor mounted in an electric vehicle.

[0058] The second load device 200 is electrically connected to the seventh node N7. That is, the output voltage of the first voltage conversion circuit 31 or the output voltage of the second voltage conversion circuit 32 is input to the second load device 200. When the fourth switch 33 is on and the fifth switch 34 is off, the output voltage of the first voltage conversion circuit 31 is input to the second load device 200. When the fourth switch 33 is off and the fifth switch 34 is on, the output voltage of the second voltage conversion circuit 32 is input to the second load device 200. For example, the second load device 200 is a vehicle control device or battery mounted on an electric vehicle.

[0059] As described above, the power supply system 1 of this embodiment has a redundant structure, which can continuously supply DC power to the second load device 200 even if either the first voltage conversion circuit 31 or the second voltage conversion circuit 32 fails.

[0060] The power supply system 1 of this embodiment has a parallel mode and a series mode as operating modes. The parallel mode operates when the first DC power supply 11 and the second DC power supply 12 are connected in parallel (parallel state). The series mode operates when the first DC power supply 11 and the second DC power supply 12 are connected in series (series state). The control device 50 switches between the parallel mode and the series mode by controlling the switches included in the power switching circuit 20.

[0061] In addition to parallel and series modes, power supply system 1 also has a heating mode, a voltage balancing mode, and a fault protection mode as operating modes. The heating mode heats the first DC power supply 11 and the second DC power supply 12 using a chopping method. The voltage balancing mode ensures that the voltage of the first DC power supply 11 is equal to the voltage of the second DC power supply 12. When the voltage of the first DC power supply 11 differs from the voltage of the second DC power supply 12, a short-circuit current flows from one of the first DC power supply 11 to the other. To prevent this, the voltage balancing mode is implemented. The fault protection mode is used to continuously supply power to the second load device 200 while preventing damage to the circuit components within power supply system 1 in the event of an overcurrent or other fault in the first load device 100. It should be noted that the detailed descriptions of the operating modes and operating states of power supply system 1 will follow.

[0062] <Series and Parallel Modes>

[0063] Figure 2 This diagram illustrates the states of each switch and contactor when power system 1 operates in series. It should be noted that... Figure 2 In the middle, only show Figure 1 The structure shown is the structure required for the illustration.

[0064] like Figure 2 As shown, in the series mode, the control device 50 controls the first contactor 13, the second contactor 14, the third contactor 15, the fourth contactor 16, the fifth contactor 41 and the sixth contactor 42 to the ON state, controls the first switch SW1 and the third switch SW3 to the OFF state, and controls the second switch SW2 to the ON state.

[0065] As a result, in series mode, the first DC power supply 11 and the second DC power supply 12 are connected in series between the third node N3 and the fourth node N4. In this case, the potential difference between the third node N3 and the fourth node N4, i.e., the output voltage Vo of the power switching circuit 20, is represented by the following equation (1). Thus, when the power system 1 operates in series mode, the output voltage Vo of the power switching circuit 20, represented by the following equation (1), is input to the first voltage conversion circuit 31 and the second voltage conversion circuit 32, respectively.

[0066] Vo=Vs1+Vs2 …(1)

[0067] Figure 3 This diagram illustrates the states of each switch and contactor when power system 1 operates in parallel mode. It should be noted that... Figure 3 In the middle, only show Figure 1 The structure shown is the structure required for the illustration.

[0068] like Figure 3 As shown, in parallel mode, the control device 50 controls the first contactor 13, the second contactor 14, the third contactor 15, the fourth contactor 16, the fifth contactor 41 and the sixth contactor 42 to be in the ON state, controls the first switch SW1 and the third switch SW3 to be in the ON state, and controls the second switch SW2 to be in the OFF state.

[0069] As a result, in parallel mode, the first DC power supply 11 and the second DC power supply 12 are connected in parallel between the third node N3 and the fourth node N4. In this case, the output voltage Vo of the power switching circuit 20 is represented by the following equation (2). Thus, when the power system 1 operates in parallel mode, the output voltage Vo of the power switching circuit 20, represented by the following equation (2), is input to the first voltage conversion circuit 31 and the second voltage conversion circuit 32, respectively.

[0070] Vo=Vs1=Vs2 …(2)

[0071] <Heating Mode>

[0072] Figures 4A-4C This is a diagram showing the current path when power supply system 1 operates in heating mode. It should be noted that... Figures 4A-4C In the middle, only show Figure 1 The structure shown is the structure required for the illustration.

[0073] In heating mode, the control device 50 controls the power switching circuit 20, alternately switching between power supply and power supply modes. Figure 4A The first state shown is the same as Figure 4BThe second state is shown. It should be noted that the switching frequency between the first and second states is, for example, tens to hundreds of kHz.

[0074] It should be noted that during the operation of the power system 1 in heating mode, the control device 50 controls the first contactor 13, the second contactor 14, the third contactor 15, the fourth contactor 16, the fifth contactor 41 and the sixth contactor 42 to be in the on state respectively.

[0075] Here, control device 50 is from Figure 4A The first state shown is switched to Figure 4B In the second state shown, let's temporarily set it to... Figure 4C After the third state shown, switch to Figure 4B The second state is shown. Additionally, the control device 50 is in the second state from... Figure 4B The second state shown is switched to Figure 4A In the first state shown, let's temporarily set it to... Figure 4C After the third state shown, switch to Figure 4A The first state is shown.

[0076] Here, the first state described above is a state where the first DC power supply 11 is connected between the third node N3 and the fourth node N4 via the first reactor 21, and the second DC power supply 12 is connected across the second reactor 22. The second state described above is a state where the second DC power supply 12 is connected between the third node N3 and the fourth node N4 via the second reactor 22, and the first DC power supply 11 is connected across the first reactor 21. The third state described above is a state where the first DC power supply 11 is connected between the third node N3 and the fourth node N4 via the first reactor 21, and the second DC power supply 12 is connected between the third node N3 and the fourth node N4 via the second reactor 22. It should be noted that, according to... Figures 4A to 4C It can be seen that in the heating mode, at least one of the first DC power supply 11 and the second DC power supply 12 is connected between the third node N3 and the fifth node N5.

[0077] like Figure 4A As shown, the control device 50 sets the first state described above by setting the first switch SW1 to the off state and setting the second switch SW2 and the third switch SW3 to the on state.

[0078] In the first state, a current loop LP11 is formed, passing sequentially through the third switch SW3, the first reactor 21, the first DC power supply 11, and the smoothing capacitor 23. Additionally, a current loop LP12 is also formed, passing sequentially through the second DC power supply 12, the second reactor 22, the second switch SW2, and the third switch SW3. Current loop LP11 is the current path of the first DC power supply 11 connected between the third node N3 and the fourth node N4 via the first reactor 21.

[0079] The current loop LP12 is the current path in the state where the two ends of the second DC power supply 12 and the second reactor 22 are connected.

[0080] like Figure 4B As shown, the control device 50 is set to the second state described above by setting the first switch SW1 and the second switch SW2 to the on state and setting the third switch SW3 to the off state.

[0081] In the second state, a current loop LP13 is formed, sequentially passing through the first DC power supply 11, the first switch SW1, the second switch SW2, and the first reactor 21. Additionally, a current loop LP14 is formed, sequentially passing through the second DC power supply 12, the second reactor 22, the first switch SW1, and the smoothing capacitor 23. Current loop LP13 is the current path when the first DC power supply 11 and the first reactor 21 are connected at both ends. Current loop LP14 is the current path when the second DC power supply 12 is connected between the third node N3 and the fourth node N4 via the second reactor 22.

[0082] like Figure 4C As shown, the control device 50 is set to the third state described above by setting the first switch SW1 and the third switch SW3 to the off state and setting the second switch SW2 to the on state.

[0083] In the third state, it forms Figure 4A The current loop LP11 shown and Figure 4B The current loop LP14 is shown. That is, in the third state, the first DC power supply 11 and the second DC power supply 12 are connected in parallel between the third node N3 and the fourth node N4.

[0084] Figure 5 This is a diagram showing the current changes when the power supply system 1 operates in heating mode. It should be noted that... Figure 5 In the middle, will be in Figure 4A The period of the first state shown is set as period Ta1, and it will be in the state of... Figure 4B The period for the second state shown is set as period Tb1. Additionally, from... Figure 4A The first state shown is switched to Figure 4B In the second state shown, temporarily in Figure 4CThe period for the third state shown is set to period Ta2. Additionally, it will be from... Figure 4B The second state shown is switched to Figure 4A In the first state shown, temporarily in Figure 4C The period of the third state shown is set as period Tb2.

[0085] like Figure 5 As shown, the control device 50 controls the first switch SW1, the second switch SW2, and the third switch SW3 to perform... Figures 4A to 4C The switching of each state is shown. Specifically, according to... Figure 4A The first state shown (during period Ta1) Figure 4C The third state shown (during period Ta2) Figure 4B The second state shown (during period Tb1) Figure 4C The third state shown (during period Tb2) Figure 4A The first state (during Ta1) shown is switched sequentially.

[0086] In the state Figure 4A During the first state, Ta1, the voltage Vs1 of the first DC power supply 11 is lower than the output voltage Vo of the power switching circuit 20. Therefore, as shown... Figure 5 As shown, the current Is1 flowing in the first DC power supply 11 (in Figure 4A The current flowing through the current loop LP11 shown decreases. Specifically, when the reactance of the first reactor 21 is set to L1, the rate of decrease of current Is1 is represented by dIs1 / dt = (Vs1 - Vo) / L1. In contrast, the voltage Vs2 of the second DC power supply 12 is higher than 0. Therefore, as Figure 5 As shown, the current Is2 flowing in the second DC power supply 12 (in Figure 4A The current flowing through the current loop LP12 shown increases. Specifically, when the reactance of the second reactor 22 is set to L2, the rate of increase of the current Is2 is represented by dIs2 / dt=Vs2 / L2.

[0087] In the state Figure 4B During the second state shown, period Tb1, the voltage Vs1 of the first DC power supply 11 is higher than 0. Therefore, as Figure 5 As shown, the current Is1 flowing in the first DC power supply 11 (in Figure 4B The current flowing through the current loop LP13 (as shown) increases. Specifically, the rate of increase of current Is1 is represented by dIs1 / dt = Vs1 / L1. In contrast, the voltage Vs2 of the second DC power supply 12 is lower than the output voltage Vo of the power switching circuit 20. Therefore, as Figure 5 As shown, the current Is2 flowing in the second DC power supply 12 (in Figure 4BThe current flowing through the current loop LP14 shown decreases. Specifically, the rate of decrease of current Is2 is represented by dIs2 / dt = (Vs2 - Vo) / L2.

[0088] In the state Figure 4C During periods Ta2 and Tb2 of the third state shown, the voltages Vs1 of the first DC power supply 11 and Vs2 of the second DC power supply 12 are both lower than the output voltage Vo of the power switching circuit 20. Therefore, as Figure 5 As shown, the current Is1 flowing in the first DC power supply 11 (in Figure 4C The current flowing through the current loop LP11 shown) and the current Is2 flowing through the second DC power supply 12 (in Figure 4C The current flowing through the current loop LP14 shown decreases. Specifically, the rate of decrease of current Is1 is represented by dIs1 / dt = (Vs1 - Vo) / L1, and the rate of decrease of current Is2 is represented by dIs2 / dt = (Vs2 - Vo) / L2.

[0089] Here, the voltage Vs1 of the first DC power supply 11 and the voltage Vs2 of the second DC power supply 12 are set as voltage Vs (Vs1 = Vs2 = Vs). Additionally, the reactance L1 of the first reactor 21 and the reactance L2 of the second reactor 22 are set as reactance L (L1 = L2 = L). Furthermore, the voltage Vs1 of the first DC power supply 11 and the voltage Vs2 of the second DC power supply 12 are set as reactance L (L1 = L2 = L). Figure 4A The length Ta of the first state period Ta1 shown and the state in which it is located Figure 4B The length Tb of the second state period Tb1 shown is set to length T (Ta = Tb = T). Furthermore, let the length T of the aforementioned period Ta1 or the aforementioned period Tb1 be relative to the switching period Tf (refer to...). Figure 5 The ratio of ) is less than 0.5 (T / Tf < 0.5). Thus, the amplitude ΔI_1 of the current Is1 flowing in the first DC power supply 11 and the amplitude ΔI_2 of the current Is2 flowing in the second DC power supply 12 are represented by ΔI_1 = ΔI_2 = Vs × T / L.

[0090] Figure 6 This is a graph showing the relationship between the amplitude and ratio (T / Tf) of the current flowing in power system 1 when it operates in heating mode. (Refer to...) Figure 6 When the power supply system 1 operates in heating mode, the amplitude ΔI of the current Is1 flowing in the first DC power supply 11 and the current Is2 flowing in the second DC power supply 12 is proportional to the ratio (T / Tf). It should be noted that the amplitude ΔI becomes 0 when the ratio (T / Tf) is 0, and becomes the maximum when the ratio (T / Tf) is 0.5.

[0091] That is, with Figure 5As the ratio of periods Ta2 and Tb2 in the switching cycle Tf increases, the amplitude ΔI of the current Is1 flowing in the first DC power supply 11 and the current Is2 flowing in the second DC power supply 12 decreases. Conversely, as... Figure 5 As the ratio of periods Ta2 and Tb2 in the switching cycle Tf decreases, the amplitude ΔI of the current Is1 flowing in the first DC power supply 11 and the current Is2 flowing in the second DC power supply 12 increases. Therefore, in order to efficiently heat the first DC power supply 11 and the second DC power supply 12, it is desirable to minimize the... Figure 5 The ratio of period Ta2 and period Tb2 in the switching period Tf shown.

[0092] By conducting Figure 5 The switching shown involves alternating boost operations of the first DC power supply 11 and the second DC power supply 12 when at least one of the first DC power supply 11 and the second DC power supply 12 is connected between the third node N3 and the fifth node N5. This allows high-frequency current to flow through both the first DC power supply 11 and the second DC power supply 12, thus enabling efficient heating of both power supplies.

[0093] <Voltage Balance Mode>

[0094] (1) First voltage balance mode

[0095] Figure 7A , 7B This diagram illustrates the current path of power supply system 1 when it operates in the first voltage balance mode. It should be noted that... Figure 7A , 7B Only shown in Figure 1 The structure shown is the structure required for explanation. The first voltage balancing mode is performed to make the voltages Vs1 of the first DC power supply 11 equal to the voltages Vs2 of the second DC power supply 12, when the voltage Vs1 of the first DC power supply 11 is higher than the voltage Vs2 of the second DC power supply 12. In the first voltage balancing mode, the control device 50 controls the power switching circuit 20 to alternately switch... Figure 7A The energy movement state shown is related to Figure 7B The energy recovery status is shown.

[0096] It should be noted that during the period when the power supply system 1 operates in the first voltage balance mode, the control device 50 controls the first contactor 13, the second contactor 14, the third contactor 15, the fourth contactor 16, the fifth contactor 41 and the sixth contactor 42 to be in the on state respectively.

[0097] here, Figure 7AThe energy movement state shown is the state in which the first DC power supply 11 and the second DC power supply 12 are connected in parallel. Figure 7B The energy recovery state shown is the state in which the first DC power supply 11 is connected via the smoothing capacitor 23, the third switch SW3 and the first reactor 21, and the second DC power supply 12 is connected to the two ends of the second reactor 22.

[0098] exist Figure 7A In the energy movement state shown, electrical energy moves from the higher-voltage first DC power supply 11 to the second DC power supply 12. However, when the voltage difference between the first DC power supply 11 and the second DC power supply 12 is large, the peak value Ip of the current flowing through the first DC power supply 11 and the second DC power supply 12 increases. Therefore, when the magnitude of the current flowing through the first DC power supply 11 and the second DC power supply 12 reaches a certain value, the system switches to an energy recovery state to stop the movement of electrical energy from the higher-voltage first DC power supply 11 to the second DC power supply 12.

[0099] exist Figure 7B In the energy recovery state shown, in order to reduce the peak value Ip of the increased current flowing in the first DC power supply 11 and the second DC power supply 12, the electrical energy stored in the first reactor 21 and the second reactor 22 is recovered to the first DC power supply 11 and the second DC power supply 12, respectively. Figure 7B The energy recovery state shown continues until the current Is1 flowing in the first DC power supply 11 and the current Is2 flowing in the second DC power supply 12 both become 0.

[0100] like Figure 7A As shown, the control device 50 sets the energy movement state described above by performing a control (first control) that turns the first switch SW1 on and turns the second switch SW2 and the third switch SW3 off. In the energy movement state, a current loop LP20 is formed, passing sequentially through the first DC power supply 11, the first switch SW1, the second reactor 22, the second DC power supply 12, the third switch SW3, and the first reactor 21. The current loop LP20 is a current path in which the first DC power supply 11 and the second DC power supply 12 are connected in parallel.

[0101] like Figure 7BAs shown, the control device 50 sets itself to the aforementioned energy recovery state by performing a control (second control) that sets the first switch SW1, the second switch SW2, and the third switch SW3 to the open state. In the energy recovery state, a current loop LP21 is formed, sequentially passing through the first DC power supply 11, the smoothing capacitor 23, the third switch SW3, and the first reactor 21. Additionally, a current loop LP22 is formed, sequentially passing through the second DC power supply 12, the third switch SW3, the second switch SW2, and the second reactor 22. Current loop LP21 is the current path when the first DC power supply 11 and the first reactor 21 are connected at both ends, and current loop LP22 is the current path when the second DC power supply 12 and the second reactor 22 are connected at both ends.

[0102] Figure 8 This is a graph showing the current changes when power supply system 1 operates in the first voltage balance mode. It should be noted that... Figure 8 In the middle, will be in Figure 7A The period of the energy movement state shown is set as period Tc1, and the state in which the energy movement state is shown will be... Figure 7B The period for the energy recovery state shown is denoted as period Tc2. For example... Figure 8 As shown, the control device 50 controls the power switching circuit 20, alternately switching power. Figure 7A The energy movement state shown is related to Figure 7B The energy recovery status is shown.

[0103] In the state Figure 7A During the energy movement period Tc1 shown, the current Is1 flowing through the first DC power supply 11 decreases, while the current Is2 flowing through the second DC power supply 12 increases. When the time from the start of period Tc1 is set to t, the current Is2 flowing through the second DC power supply 12 is represented by Is2 = (Vs1 - Vs2) / (L1 + L2) × t. When the length of period Tc1 is set to t_c1, the peak value Ip of the current Is flowing through the first DC power supply 11 and the second DC power supply 12 is represented by Ip = (Vs1 - Vs2) / (L1 + L2) × t_c1.

[0104] In the state Figure 7BDuring the energy recovery period Tc2 shown, both the current Is1 flowing through the first DC power supply 11 and the current Is2 flowing through the second DC power supply 12 decrease to zero. The time required for the current Is1 flowing through the first DC power supply 11 to become zero is represented by Vs1 / L1×Ip. Similarly, the time required for the current Is2 flowing through the second DC power supply 12 to become zero is represented by Vs2 / L2×Ip. Therefore, the time t_c2 required for both the current Is1 flowing through the first DC power supply 11 and the current Is2 flowing through the second DC power supply 12 to become zero is the larger of Vs1 / L1×Ip and Vs2 / L2×Ip.

[0105] After Figure 8 During the switching process shown in the figure, the voltage Vs1 of the first DC power supply 11 gradually decreases, while the voltage Vs2 of the second DC power supply 12 gradually increases. Furthermore, by repeatedly performing this switching... Figure 8 As shown in the switch, the voltage Vs1 of the first DC power supply 11 and the voltage Vs2 of the second DC power supply 12 become equal. Thus, by performing control in the first voltage balance mode (first voltage balance control), the voltage Vs1 of the first DC power supply 11 and the voltage Vs2 of the second DC power supply 12 become equal.

[0106] (2) Second voltage balance mode

[0107] Figure 9A , 9B This diagram illustrates the current path of power supply system 1 when it operates in the second voltage balance mode. It should be noted that... Figure 9A , 9B Only shown in Figure 1 The structure shown is the structure required for explanation. The second voltage balancing mode is performed to make the voltage Vs1 of the first DC power supply 11 equal to the voltage Vs2 of the second DC power supply 12 when the voltage Vs2 of the second DC power supply 12 is higher than the voltage Vs1 of the first DC power supply 11. In the second voltage balancing mode, the control device 50 controls the power switching circuit 20 to alternately switch... Figure 9A The energy movement state shown is related to Figure 9B The energy recovery status is shown.

[0108] here, Figure 9A The energy movement state shown is related to Figure 9A The energy movement state shown is also the state in which the first DC power supply 11 and the second DC power supply 12 are connected in parallel. Figure 9B The energy recovery state shown is a state in which the first DC power supply 11 is connected to the two ends of the first reactor 21, and the second DC power supply 12 is connected via the second reactor 22, the first switch SW1 and the smoothing capacitor 23.

[0109] exist Figure 9A In the energy movement state shown, electrical energy moves from the higher-voltage second DC power supply 12 to the first DC power supply 11. Figure 9B In the energy recovery state shown, in order to reduce the peak value Ip of the increased current flowing in the first DC power supply 11 and the second DC power supply 12, the electrical energy stored in the first reactor 21 and the second reactor 22 is recovered to the first DC power supply 11 and the second DC power supply 12, respectively.

[0110] like Figure 9A As shown, the control device 50 sets the energy movement state described above by performing a control (third control) that sets the first switch SW1 and the second switch SW2 to the open state and the third switch SW3 to the closed state. In the energy movement state, a current loop LP30 is formed, which sequentially passes through the first DC power supply 11, the first reactor 21, the third switch SW3, the second DC power supply 12, the second reactor 22, and the first switch SW1. The current loop LP30 is a current path in which the first DC power supply 11 and the second DC power supply 12 are connected in parallel.

[0111] like Figure 9B As shown, the control device 50 sets the energy recovery state described above by performing a control (second control) that sets the first switch SW1, the second switch SW2, and the third switch SW3 to the open state. In the energy recovery state, a current loop LP31 is formed that sequentially passes through the first DC power supply 11, the first reactor 21, the second switch SW2, and the first switch SW1. Additionally, a current loop LP32 is formed that sequentially passes through the second DC power supply 12, the second reactor 22, the first switch SW1, and the smoothing capacitor 23. Current loop LP31 is the current path when the first DC power supply 11 and the first reactor 21 are connected at both ends, and current loop LP32 is the current path when the second DC power supply 12 is connected via the second reactor 22 and the smoothing capacitor 23.

[0112] Figure 10 This is a graph showing the current changes when power supply system 1 operates in the second voltage balance mode. It should be noted that... Figure 10 In the middle, will be in Figure 9A The period of the energy movement state shown is set as period Td1, and the state will be in the period Td1. Figure 9B The period for the energy recovery state shown is denoted as period Td2. For example... Figure 10 As shown, the control device 50 controls the power switching circuit 20, alternately switching power. Figure 9A The energy movement state shown is related to Figure 9B The energy recovery status is shown.

[0113] In the state Figure 9ADuring the energy movement period Td1, the current Is2 flowing through the second DC power supply 12 decreases, while the current Is1 flowing through the first DC power supply 11 increases. When the time following the start of period Td1 is set to t, the current Is1 flowing through the first DC power supply 11 is represented by Is1 = (Vs2 - Vs1) / (L1 + L2) × t. When the length of period Td1 is set to t_d1, the peak value Ip of the current Is flowing through the first DC power supply 11 and the second DC power supply 12 is represented by Ip = (Vs2 - Vs1) / (L1 + L2) × t_d1.

[0114] In the state Figure 9B During the energy recovery state shown, the current Is1 flowing through the first DC power supply 11 and the current Is2 flowing through the second DC power supply 12 both decrease to zero during the period Td2. It should be noted that the time t_d2 required for both the current Is1 flowing through the first DC power supply 11 and the current Is2 flowing through the second DC power supply 12 to become zero is similarly the larger of Vs1 / L1×Ip and Vs2 / L2×Ip when operating in the first voltage balance mode.

[0115] After Figure 10 During the switching process shown in the figure, the voltage Vs2 of the second DC power supply 12 gradually decreases, while the voltage Vs1 of the first DC power supply 11 gradually increases. Furthermore, by repeatedly performing this switching... Figure 10 As shown in the switch, the voltage Vs1 of the first DC power supply 11 and the voltage Vs2 of the second DC power supply 12 become equal. Thus, by performing control in the second voltage balance mode (second voltage balance control), the voltage Vs1 of the first DC power supply 11 and the voltage Vs2 of the second DC power supply 12 become equal.

[0116] Figure 11 This is a flowchart illustrating the process of voltage balance control in power supply system 1. It should be noted that... Figure 11 The flowchart shown begins, for example, each time the host device (not shown) gives a transfer instruction to the control device 50 of the power system 1 to switch to a parallel connection. Such a transfer instruction is, for example, given the start-up of an electric vehicle.

[0117] like Figure 11 As shown, when the process begins, the control device 50 determines whether the difference (voltage difference) between the voltage Vs1 of the first DC power supply 11 detected by the first voltage sensor 17 and the voltage Vs2 of the second DC power supply 12 detected by the second voltage sensor 18 is greater than or equal to a predetermined reference value (step S11). If the control device 50 determines that the voltage difference is not greater than or equal to the reference value, the process ends. Figure 11The process is as shown. In contrast, if the control device 50 determines that the voltage difference is greater than or equal to the reference value, it determines whether the state indicated by the upper device is a parallel state (step S12).

[0118] If the control device 50 determines that the state indicated by the upper-level device is not a parallel state, it terminates the operation. Figure 11 The process is shown below. In contrast, when the control device 50 determines that the state indicated by the upper device is a parallel state, it determines whether the value obtained by subtracting the voltage Vs2 of the second DC power supply 12 from the voltage Vs1 of the first DC power supply 11 (hereinafter referred to as the first potential difference) is smaller than a predetermined threshold (step S13).

[0119] When the control device 50 determines that the first potential difference is not less than the aforementioned threshold (is greater than or equal to the aforementioned threshold), it switches to using... Figure 7A , 7B and Figure 8 The first voltage balance mode is described, and first voltage balance control is performed (step S14). It should be noted that the control device 50 performs the first voltage balance control in step S14 until it is determined in step S13 that the first potential difference is smaller than the threshold. In contrast, when the control device 50 determines that the first potential difference is smaller than the threshold, it determines whether the value obtained by subtracting the voltage Vs1 of the first DC power supply 11 from the voltage Vs2 of the second DC power supply 12 (hereinafter referred to as the second potential difference) is larger than a predetermined threshold (step S15).

[0120] When the control device 50 determines that the second potential difference is not less than the aforementioned threshold (is greater than or equal to the aforementioned threshold), it switches to using... Figure 9A , 9B and Figure 10 The second voltage balance mode described above is used for second voltage balance control (step S16). It should be noted that the control device 50 performs the second voltage balance control in step S16 until it is determined in step S15 that the second potential difference is smaller than the threshold value. Conversely, when the control device 50 determines that the second potential difference is smaller than the threshold value, it performs... Figure 3 The control of the parallel state transition shown is in step S17. After the above processing is completed, the control device 50 terminates. Figure 11 The processing shown.

[0121] <Fault Protection Mode>

[0122] Figure 12 This is the first diagram showing the status of each switch and contactor when the power system 1 operates in fault protection mode. It should be noted that... Figure 12 Only shown in Figure 1The structure shown is the structure required for the description. When the control device 50 detects a fault such as overcurrent in the first load device 100, it switches to a fault protection mode, such as... Figure 12 As shown, each switch and contactor is controlled.

[0123] Specifically, such as Figure 12 As shown, in fault protection mode, the control device 50 controls the first contactor 13, the second contactor 14 and the fourth contactor 16 to the open state, controls the third contactor 15, the fifth contactor 41 and the sixth contactor 42 to the closed state, controls the first switch SW1 and the third switch SW3 to the closed state, and controls the second switch SW2 to the open state.

[0124] As a result, the potential difference between the first node N1 and the fourth node N4, i.e., the input voltage of the first voltage conversion circuit 31, becomes approximately equal to the voltage Vs1 of the first DC power supply 11. Therefore, even if the first load device 100 fails, power can be continuously supplied from the first voltage conversion circuit 31 to the second load device 200. Furthermore, the first DC power supply 11 and the second DC power supply 12 are electrically disconnected from the first load device 100. As a result, the power supply to the first load device 100 is stopped, thus preventing the flow of large currents within the power system 1.

[0125] Figure 13 This is a second diagram showing the status of each switch and contactor when power system 1 operates in fault protection mode. It should be noted that... Figure 13 Only shown in Figure 1 The structure shown is the structure required for the description. When the control device 50 detects a fault such as overcurrent in the first load device 100, it switches to a fault protection mode, such as... Figure 13 As shown, each switch and contactor is controlled. It should be noted that when the control device 50 switches to fault protection mode, it can... Figure 12 Controlling each switch and contactor as shown can also be done as follows: Figure 13 Control each switch and contactor as shown.

[0126] Specifically, such as Figure 13 As shown, in fault protection mode, the control device 50 controls the first contactor 13, the second contactor 14 and the third contactor 15 to the open state, controls the fourth contactor 16, the fifth contactor 41 and the sixth contactor 42 to the closed state, controls the first switch SW1 and the third switch SW3 to the closed state, and controls the second switch SW2 to the open state.

[0127] As a result, the potential difference between the third node N3 and the second node N2, i.e., the input voltage of the second voltage conversion circuit 32, becomes approximately equal to the voltage Vs2 of the second DC power supply 12. Therefore, even if the first load device 100 fails, power can be continuously supplied to the second load device 200 from the second voltage conversion circuit 32. Furthermore, the first DC power supply 11 and the second DC power supply 12 are electrically disconnected from the first load device 100. As a result, the power supply to the first load device 100 is stopped, thus preventing the flow of large currents within the power system 1.

[0128] Figure 14 This is the third diagram showing the status of each switch and contactor when power system 1 operates in fault protection mode. It should be noted that... Figure 14 Only shown in Figure 1 The structure shown is the structure required for the description. When the control device 50 detects a fault such as overcurrent in the first load device 100, it switches to a fault protection mode, such as... Figure 14 As shown, each switch and contactor is controlled. It should be noted that when the control device 50 switches to fault protection mode, it can... Figure 12 or Figure 13 Controlling each switch and contactor as shown can also be done as follows: Figure 14 Control each switch and contactor as shown.

[0129] Specifically, such as Figure 14 As shown, in fault protection mode, the control device 50 controls the first contactor 13 and the second contactor 14 to be in the open state, controls the third contactor 15, the fourth contactor 16, the fifth contactor 41 and the sixth contactor 42 to be in the closed state, controls the first switch SW1 and the third switch SW3 to be in the closed state, and controls the second switch SW2 to be in the open state.

[0130] As a result, the potential difference between the first node N1 and the fourth node N4, i.e., the input voltage of the first voltage conversion circuit 31, becomes approximately equal to the voltage Vs1 of the first DC power supply 11; and the potential difference between the third node N3 and the second node N2, i.e., the input voltage of the second voltage conversion circuit 32, becomes approximately equal to the voltage Vs2 of the second DC power supply 12. Therefore, even if the first load device 100 fails, power can be continuously supplied to the second load device 200 from either the first voltage conversion circuit 31 or the second voltage conversion circuit 32.

[0131] Furthermore, the first DC power supply 11 and the second DC power supply 12 are electrically disconnected from the first load device 100. As a result, the power supply to the first load device 100 is stopped, thus preventing the flow of large currents within the power system 1.

[0132] As described above, in fault protection mode, control device 50 uses, for example... Figure 12 , Figure 13 or Figure 14 By controlling each switch and contactor as shown, even if an overcurrent or other fault occurs in the first load device 100, power can be continuously supplied to the second load device 200 while preventing damage to the circuit components in the power supply system 1.

[0133] As described above, the power supply system 1 of this embodiment includes: a first DC power supply 11 having a positive terminal connected to a first node N1; a second DC power supply 12 having a negative terminal connected to a second node N2; a first contactor 13 connected between the first node N1 and the third node N3; a second contactor 14 connected between the second node N2 and the fourth node N4; a third contactor 15 connected between the negative terminal of the first DC power supply 11 and the fifth node N5; a fourth contactor 16 connected between the positive terminal of the second DC power supply 12 and the sixth node N6; a first switch SW1 connected between the third node N3 and the sixth node N6; a second switch SW2 connected between the fifth node N5 and the sixth node N6; a third switch SW3 connected between the fourth node N4 and the fifth node N5; a first voltage conversion circuit 31 connected between the first node N1 and the fourth node N4; and a second voltage conversion circuit 32 connected between the second node N2 and the third node N3.

[0134] According to the embodiment described above, even if a fault such as overcurrent occurs in the first load device 100 connected between the third node N3 and the fourth node N4, at least one of the first voltage conversion circuit 31 and the second voltage conversion circuit 32 can continue to operate, thus maintaining a continuous power supply from the power supply system 1.

[0135] In this embodiment, the power supply system 1 further includes a fourth switch 33 connected between the output terminal of the first voltage conversion circuit 31 and the seventh node N7, and a fifth switch 34 connected between the output terminal of the second voltage conversion circuit 32 and the seventh node N7.

[0136] According to this embodiment as described above, even if either the first voltage conversion circuit 31 or the second voltage conversion circuit 32 fails, power can still be continuously supplied to the second load device 200, for example, connected to the seventh node N7.

[0137] In this embodiment, the power supply system 1 further includes a fifth contactor 41 connected between the first node N1 and the first voltage conversion circuit 31, the rating of the fifth contactor 41 being smaller than the rating of the first contactor 13.

[0138] According to this embodiment as described above, the wiring connecting the first node N1 and the first voltage conversion circuit 31 is a power supply-dedicated wiring for the control device 50. Therefore, the rating of the fifth contactor 41 installed on this wiring can be set to a lower rating than that of contactors used for large electrical loads such as motors. As a result, miniaturization and cost reduction of the power supply system 1 can be achieved.

[0139] In this embodiment, the power supply system 1 further includes a sixth contactor 42 connected between the second node N2 and the second voltage conversion circuit 32, the rating of the sixth contactor 42 being smaller than the rating of the second contactor 14.

[0140] According to this embodiment as described above, the wiring connecting the second node N2 and the second voltage conversion circuit 32 is a power supply-dedicated wiring for the control device 50. Therefore, the rating of the sixth contactor 42 installed on this wiring can be set to a lower rating than that of contactors used for large electrical loads such as motors. As a result, miniaturization and cost reduction of the power supply system 1 can be achieved.

[0141] In this embodiment, the power supply system 1 further includes a control device 50. When the control device 50 detects a fault in the first load device 100 connected between the third node N3 and the fourth node N4, it controls the first contactor 13, the second contactor 14 and the fourth contactor 16 to be in an open state, controls the third contactor 15 to be in an on state, controls the first switch SW1 and the third switch SW3 to be in an on state, and controls the second switch SW2 to be in an open state.

[0142] According to the embodiment described above, even if the first load device 100 connected between the third node N3 and the fourth node N4 experiences a fault such as overcurrent, the first voltage conversion circuit 31 can continue to operate while the first DC power supply 11 and the second DC power supply 12 are electrically disconnected from the first load device 100.

[0143] In this embodiment, the power supply system 1 further includes a control device 50. When the control device 50 detects a fault in the first load device 100 connected between the third node N3 and the fourth node N4, it controls the first contactor 13, the second contactor 14 and the third contactor 15 to be in an open state, controls the fourth contactor 16 to be in an on state, controls the first switch SW1 and the third switch SW3 to be in an on state, and controls the second switch SW2 to be in an open state.

[0144] According to the embodiment described above, even if the first load device 100 connected between the third node N3 and the fourth node N4 experiences a fault such as overcurrent, the second voltage conversion circuit 32 can continue to operate while the first DC power supply 11 and the second DC power supply 12 are electrically disconnected from the first load device 100.

[0145] In this embodiment, the power supply system 1 further includes a control device 50. When the control device 50 detects a fault in the first load device 100 connected between the third node N3 and the fourth node N4, it controls the first contactor 13 and the second contactor 14 to be in an open state, controls the third contactor 15 and the fourth contactor 16 to be in an on state, controls the first switch SW1 and the third switch SW3 to be in an on state, and controls the second switch SW2 to be in an open state.

[0146] According to the present embodiment described above, even if the first load device 100 connected between the third node N3 and the fourth node N4 experiences a fault such as overcurrent, it is possible to continuously operate both the first voltage conversion circuit 31 and the second voltage conversion circuit 32 while electrically disconnecting the first DC power supply 11 and the second DC power supply 12 from the first load device 100.

[0147] The above describes one embodiment of the present invention, but the present invention is not limited to the above embodiment and can be modified and replaced in various ways without departing from the spirit of the present invention.

[0148] For example, in the above embodiment, an example was described where the first reactor 21 is disposed between the third contactor 15 and the fifth node N5, and the second reactor 22 is disposed between the fourth contactor 16 and the sixth node N6. However, the first reactor 22 may also be disposed between the first contactor 13 and the third node N3. Additionally, the second reactor 22 may also be disposed between the second contactor 14 and the fourth node N4.

[0149] Furthermore, the control device 50 can be implemented using a computer, such as an embedded computer. When the control device 50 is implemented by a computer, the functions of each component of the control device 50 are achieved by the CPU (Central Processing Unit) of the computer executing programs to implement these functions. That is, the functions of each component of the control device 50 are achieved through the coordinated use of software and hardware resources. It should be noted that the control device 50 can also be implemented using hardware such as FPGA (Field-Programmable Gate Array), LSI (Large Scale Integration), or ASIC (Application Specific Integrated Circuit).

Claims

1. A power supply system, wherein, The power supply system includes: A first DC power supply having a positive terminal connected to a first node; The second DC power supply has a negative terminal connected to the second node; A first contactor is connected between the first node and the third node; The second contactor is connected between the second node and the fourth node; The third contactor is connected between the negative terminal of the first DC power supply and the fifth node; The fourth contactor is connected between the positive terminal of the second DC power supply and the sixth node; A first switch is connected between the third node and the sixth node; A second switch is connected between the fifth node and the sixth node; A third switch is connected between the fourth node and the fifth node; A first voltage conversion circuit is connected between the first node and the fourth node; and A second voltage conversion circuit is connected between the second node and the third node.

2. The power supply system according to claim 1, wherein, The power supply system also features: A fourth switch is connected between the output terminal of the first voltage conversion circuit and the seventh node; and The fifth switch is connected between the output terminal of the second voltage conversion circuit and the seventh node.

3. The power supply system according to claim 1, wherein, The power supply system also includes a fifth contactor connected between the first node and the first voltage conversion circuit. The rating of the fifth contactor is smaller than that of the first contactor.

4. The power supply system according to claim 1, wherein, The power supply system also includes a sixth contactor connected between the second node and the second voltage conversion circuit. The rating of the sixth contactor is smaller than that of the second contactor.

5. The power supply system according to claim 1, wherein, The power system also includes a control device. When the control device detects a fault in the first load device connected between the third node and the fourth node, it controls the first contactor, the second contactor, and the fourth contactor to be in an open state, controls the third contactor to be in an on state, controls the first switch and the third switch to be in an on state, and controls the second switch to be in an open state.

6. The power supply system according to claim 1, wherein, The power system also includes a control device. When the control device detects a fault in the first load device connected between the third node and the fourth node, it controls the first contactor, the second contactor, and the third contactor to be in an open state, controls the fourth contactor to be in an on state, controls the first switch and the third switch to be in an on state, and controls the second switch to be in an open state.

7. The power supply system according to claim 1, wherein, The power system also includes a control device. When the control device detects a fault in the first load device connected between the third node and the fourth node, it controls the first contactor and the second contactor to be in an open state, controls the third contactor and the fourth contactor to be in an on state, controls the first switch and the third switch to be in an on state, and controls the second switch to be in an open state.

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