Switching power supply, vehicle and control method

Abstract

Switching power supply (100; 200; 300), comprising: a plurality of power supply circuits (1a, 1b; 1a, 1b, 1c) corresponding to respective phases of a multi-phase AC power supply (10b; 10c) as an external power supply, each of the power supply circuits including a filter circuit (2), a voltmeter (5) and an AC / DC converter (3), the AC / DC converter (3) being configured to convert AC power output from the filter circuit (2) into DC power, the voltmeter (5) measuring a voltage of an output capacitor included in the AC / DC converter (3); a switch circuit (7; 7, 7a) configured to switch a connection destination of another power supply circuit among the power supply circuits (1a, 1b; 1a, 1b, 1c), which is other than a specific power supply circuit corresponding to a specific phase of the external power supply, to a phase corresponding to the other power supply circuit or the specific phase; an inrush current prevention circuit (12) configured to prevent an inrush current, the inrush current prevention circuit being arranged on a power supply line on a negative side of the external power supply and at a position closer to the external power supply than a connection point to which the power supply circuits (1a, 1b; 1a, 1b, 1c) are connected, and a control unit (17) designed to control the switching circuit (7; 7, 7a) according to a number of phases of the external voltage supply connected to the switching power supply, wherein the control unit (17) is designed to connect the other power supply circuit corresponding to the phase to each phase of the external power supply connected to the switching power supply, and to connect the other power supply circuit surplus to the specific phase if the number of phases of the external power supply connected to the switching power supply is smaller than a number of the power supply circuits (1a, 1b; 1a, 1b, 1c), the control unit (17) is designed to determine the number of phases of the external power supply connected to the switching power supply on the basis of a voltage value measured by the voltmeter, the control unit (17) is designed: connect the other power supply circuit to the specific phase and de-energise a relay included in the inrush current prevention circuit to perform an initial charging of the output capacitor; and to make the relay of the inrush current prevention circuit conductive, while leaving the other power supply circuit surplus connected to the specific phase after the initial charging of the output capacitor, if the number of phases of the external power supply connected to the switching power supply is smaller than the number of power supply circuits (1a, 1b; 1a, 1b, 1c), and when the switching power supply (100, 200, 300) is connected to the single-phase AC power supply (10a) and a voltage value of the single-phase AC power supply (10a) is equal to or less than a predetermined value, the control unit (17) is configured to connect a power supply circuit from the plurality of power supply circuits that does not correspond to the phase of the single-phase AC power supply (10a) in excess to the phase of the single-phase AC power supply (10a) in order to carry out the initial charging of the output capacitor.

Description

Area

[0001] Embodiments described herein generally relate to a switching power supply, a vehicle, and a control method. background

[0002] In order to avoid the need for a noise suppression filter of a relay driver circuit and to reduce the size of a device, a switching power supply device according to WO 2019 / 124555 A1 is provided with a plurality of power supply circuits corresponding to each phase of a multi-phase AC power supply, the switching power supply device being provided with: a switching circuit capable of switching a phase connected to a power supply circuit that does not correspond to any phase of the multi-phase AC power supply, from the plurality of power supply circuits, to any one phase or to the phase to which the power supply circuit corresponds; an inrush current prevention circuit for preventing an inrush current, the inrush current prevention circuit being provided on a power supply line of the multi-phase AC power supply on the negative electrode side and at a positionwhich is located further toward the multi-phase AC power supply than a connection point to which each of the plurality of power supply circuits is connected; and a filter circuit provided between the multi-phase AC power supply and the inrush current prevention circuit, wherein all lines of the plurality of phases are magnetically coupled to the filter circuit.

[0003] US 2015 / 0115888 A1 relates to a charging device for a battery of a motorized device, which is suitable for being supplied with a single-phase input alternating current and which is suitable for being supplied with a multi-phase input alternating current, wherein the charging device comprises a first conversion module and a second conversion module, wherein the first conversion module is suitable for converting an alternating current into at least one intermediate direct current and supplying the second conversion module with this intermediate current, and wherein the second conversion module is suitable for converting the intermediate current into an output direct current and supplying the battery with this output current;wherein the charging device also comprises a switching module capable of switching the first conversion module between a first configuration adapted to a first single-phase AC input current and a second configuration adapted to a multi-phase AC input current;

[0004] DE 10 2018 203 489 A1 relates to an AC charging device for a motor vehicle, comprising a neutral conductor, at least one phase conductor and at least one rectifier, wherein the neutral conductor and the phase conductor are connected to a rectifier to which at least one smoothing capacitor is also connected, and the AC charging device has a pre-charging circuit arranged between a power grid connection and the smoothing capacitor, which is designed to pre-charge the smoothing capacitor, wherein the pre-charging circuit has at least one transistor.

[0005] According to the prior art, a switching power supply is known that can convert AC power from a single-phase or multi-phase AC power supply into DC power (for example, Japanese Patent Application No. 2017-169350).

[0006] The switching power supply disclosed in Japanese Patent Application No. 2017-169350 includes three power conversion lines arranged in parallel, each of which includes a noise filter and a power converter.

[0007] This switching power supply charges a battery according to the number of phases of an AC power supply to be connected by connecting the power conversion line corresponding to each phase to each phase of the external AC power supply.

[0008] In this way, by designing the switching power supply such that it can be connected to any single-phase AC power supply or a multi-phase AC power supply, it is possible to charge the battery with any infrastructure consisting of a single-phase AC power supply and a multi-phase AC power supply.

[0009] However, in the prior art switching power supply arrangement, the ability to reduce noise may be insufficient in some cases.

[0010] An object of the present disclosure is to improve the performance of a noise protection filter of the switching power supply. Summary

[0011] A switching power supply according to an embodiment of the present disclosure is defined in claim 1. Short description of the drawing Fig. 1 is a circuit diagram illustrating a case where a switching power supply according to a first embodiment is connected to a single-phase AC power supply; Fig. 2 is a circuit diagram illustrating a case where the switching power supply according to the first embodiment is connected to a two-phase AC power supply; Fig. 3 is a circuit diagram illustrating a case where the switching power supply according to the first embodiment is connected to the two-phase AC power supply; Fig. 4 is a circuit diagram showing an arrangement example of an inrush current prevention circuit of the switching power supply according to the first embodiment; Fig. 5 is a flowchart illustrating an operation example of the switching power supply according to the first embodiment; Fig. 6 is a circuit diagram illustrating a case where a switching power supply according to a second embodiment is connected to a single-phase AC power supply; Fig. 7 is a circuit diagram illustrating a case where the switching power supply according to the second embodiment is connected to a two-phase AC power supply; Fig. 8 is a circuit diagram illustrating a case where the switching power supply according to the second embodiment is connected to a three-phase AC power supply; Fig. 9 is a flowchart illustrating an operation example of the switching power supply according to the second embodiment; Fig. 10 is a flowchart illustrating an operation example of a switching power supply according to a modification of the second embodiment; Fig. 11 is a circuit diagram illustrating a case where a switching power supply according to a third embodiment is connected to a single-phase AC power supply; and Fig. 12 is a circuit diagram showing a case where the switching power supply according to the third embodiment is connected to the single-phase AC power supply. Detailed description

[0012] The following describes embodiments of the present disclosure in detail with reference to the drawings. First embodiment

[0013] First, the following describes an example of a configuration of a switching power supply 100 according to the present embodiment. Fig. 1 is a circuit diagram illustrating an arrangement example of the switching power supply 100. For example, the switching power supply 100 is used in a charging device of a vehicle, such as an electric vehicle and a hybrid vehicle. Structure of the switching power supply 100

[0014] The switching power supply 100 is a device that converts AC power from an AC power supply into DC power to be output to a battery 20. For example, Fig. 1 illustrates a case where the switching power supply 100 is connected to a single-phase AC power supply 10a, but the switching power supply 100 may be connected to a two-phase AC power supply 10b, as in Fig. 2 and Fig. 3. The switching power supply 100 according to the present embodiment is designed to be compatible with the single-phase AC power supply 10a and the two-phase AC power supply 10b. Hereinafter, in a case where it is not necessary to distinguish between the single-phase AC power supply 10a and the two-phase AC power supply 10b (a three-phase AC power supply 10c described below), they are simply referred to as "AC power supply." Furthermore, the two-phase AC power supply 10b and the three-phase AC power supply 10c are also referred to as "multi-phase AC power supply."

[0015] The battery 20 is, for example, a battery for powering an engine of a vehicle. The battery 20 is a high-capacity battery, and examples thereof include a lithium-ion battery. Alternatively, the battery 20 may be a battery used for a mobile phone, household electrical appliances, and the like, in addition to a battery used for a vehicle.

[0016] The switching power supply 100 includes a power supply circuit 1a, a power supply circuit 1b, a switch circuit 7, an inrush current prevention circuit 12, and a control unit 17. In the present embodiment, the switching power supply 100 has a structure including two power supply circuits (the power supply circuits 1a and 1b) to be compatible with the single-phase AC power supply 10a and the two-phase AC power supply 10b.

[0017] Each of the power supply circuits 1a and 1b includes a power supply filter 2, an AC / DC converter 3, and a DC / DC converter 6. The power supply filter 2 is an example of a filter circuit in the claims. The power supply circuits 1a and 1b are connected to the AC power supply via the power supply lines L1 and L2, respectively.

[0018] The AC power is input from the AC power supply to the power supply filter 2. The power supply filter 2 prevents noise from entering the power supply line and prevents noise from leaking to an external AC power supply.

[0019] The AC / DC converter 3 is located at a rear stage of the power supply filter 2 (on the battery 20 side). The AC / DC converter 3 converts AC power from the power supply filter 2 into DC power, which is to be output to the DC / DC converter 6.

[0020] The AC / DC converter 3 includes an electrolytic capacitor 4 and a voltmeter 5 for measuring the voltage of the electrolytic capacitor 4. The voltmeter 5 measures the voltage of the electrolytic capacitor 4 at the time when the electrolytic capacitor 4 is initially charged (precharged). A voltage value measured by the voltmeter 5 is output to the control unit 17. The electrolytic capacitor 4 corresponds to an output capacitor in the claims.

[0021] The voltmeter 5 is arranged in each of the power supply circuit 1a and the power supply circuit 1b. By detecting the voltage value of the voltmeter 5, the control unit 17 can determine which of the single-phase AC power supply 10a and the two-phase AC power supply 10b is connected to the switching power supply 100.

[0022] The voltmeter 5 is not essential equipment in the present embodiment. For example, by separately disposing a current sensor in the AC / DC converter 3 to output a current value to the control unit 17, the control unit 17 can determine which of the single-phase AC power supply 10a and the two-phase AC power supply 10b is connected to the switching power supply 100 without using the voltmeter 5. In a case of separately disposing the current sensor, the installation location of the current sensor is not limited to the inside of the AC / DC converter 3.

[0023] Alternatively, by re-arranging another voltmeter at a rear stage of the AC / DC converter 3, separate from the voltmeter 5, the control unit 17 can determine, based on a voltage value of the other voltmeter, which of the single-phase AC power supply 10a and the two-phase AC power supply 10b is connected to the switching power supply 100. In a case of re-arranging another voltmeter separately, a mounting location of the another voltmeter is not limited to the rear stage of the AC / DC converter 3.

[0024] As another method, by arranging a communication module for communicating with the AC power supply, it can be determined based on the information transmitted from the communication module regarding the AC power supply which is connected to the switching power supply 100 from among the single-phase AC power supply 10a and the two-phase AC power supply 10b.

[0025] The DC / DC converter 6 is arranged at a rear stage of the AC / DC converter 3 (on the battery 20 side). The DC / DC converter 6 converts the DC voltage applied from the AC / DC converter 3 into another DC voltage value with a different voltage value, which is to be output to the battery 20.

[0026] The switching circuit 7 is a circuit that switches between a first mode in which only the power supply circuit 1a is driven in a case where the switching power supply 100 is connected to the single-phase AC power supply 10a, and a second mode in which both the power supply circuit 1a and the power supply circuit 1b are driven in a case where the switching power supply 100 is connected to the two-phase AC power supply 10b.

[0027] In other words, the switching circuit 7 can switch, from the power supply circuits 1a and 1b as a connection destination, another power supply circuit (the power supply circuit 1b) as a specific power supply circuit (the power supply circuit 1a) corresponding to a specific phase (for example, the power supply line L1) of the multi-phase AC power supply to the phase (the power supply line L2) corresponding to the other power supply circuit (the power supply circuit 1b) or the specific phase (the power supply line L1).

[0028] The switching circuit 7 includes a switching relay 8, a coil (not shown), and a drive circuit (not shown). The drive circuit turns the switching relay 8 ON or OFF according to a control signal from the control unit 17. This control signal is a signal indicating whether to turn the switching relay 8 on or off. The switching circuit 7 is an example of a switching circuit described in the claims.

[0029] An OFF state of the switching relay 8 means a state in which the switching relay 8 is connected to the power supply line L1 branched at a branch point n2 as shown in Fig. 1 and Fig. 2. On the other hand, an ON state of the switching relay 8 means a state in which the switching relay 8 is connected to the power supply line L2, as shown in Fig. 3. The branch point n2 is a point (a position) on the power supply line L1 (the first phase) on a positive side.

[0030] The control device 17 consists of, for example, a processor such as a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and the like.

[0031] The inrush current prevention circuit 12 is arranged closer to the AC power supply side than a common point (connection point) n3 of a negative-side line of the power supply circuit 1a and the negative-side line of the power supply circuit 1b, and limits an inrush current. The common point n3 is a point on a negative-side power line N. With this arrangement, the inrush current prevention circuit 12 does not need to be arranged for each line, so the switching power supply 100 can be downsized.

[0032] Fig. 4 is a circuit diagram illustrating an arrangement example of the inrush current prevention circuit 12. The inrush current prevention circuit 12 includes an inrush current limiting circuit 13 composed of a fuse (not shown), an inrush current limiting resistor, and the like, an inrush current prevention relay 14, a coil (not shown), and a drive circuit (not shown). The drive circuit turns the inrush current prevention relay 14 ON or OFF according to a control signal from the control unit 17.

[0033] This control signal is a signal indicating whether to turn on the inrush current prevention relay 14 or to turn off the inrush current prevention relay 14. For example, Fig. 4 illustrates a case where the inrush current prevention relay 14 is in the OFF state. The control unit 17 generates the control signal when the processor, such as a CPU described above, interacts with a computer program (software) stored, for example, in a ROM. The function of the control unit 17 is not necessarily implemented by software and may also be implemented by a hardware arrangement, such as a dedicated circuit.

[0034] The inrush current prevention circuit 12 is not necessarily located closer to the single-phase AC power supply 10a side than the common connection point n3, and may be located at a different position. For example, the inrush current prevention circuit 12 may be located in either the negative-side line of the power supply circuit 1a or the negative-side line of the power supply circuit 1b.

[0035] The control unit 17 controls the switching circuit 7 according to the number of phases of the external power supply (AC power supply) connected to the switching power supply 100.

[0036] The example of the arrangement of the switching power supply 100 is described above. Operation of the switching power supply 100

[0037] Next, the following describes an example of operation of the switching power supply 100 with reference to Fig. 5. Fig. Figure 5 is a flowchart illustrating an example of operation of the switching power supply 100. The operation described below begins when the AC power supply is connected.

[0038] First, the control unit 17 determines the data of the connected AC power supply. Specifically, the control unit 17 determines whether the AC power supply is the single-phase AC power supply 10a or the two-phase AC power supply 10b (step S100).

[0039] The control unit 17 determines whether the AC power supply is the single-phase AC power supply 10a or the two-phase AC power supply 10b based on a voltage value output from the voltmeter 5, which measures, for example, the voltage of the electrolytic capacitor 4.

[0040] At the start of the flowchart, the switching relay 8 is in an ON state, as shown in Fig. 3. Thus, in a case where the switching power supply 100 is connected to the single-phase AC power supply 10a (for example, in a case where the positive side of the single-phase AC power supply 10a is connected to the power supply line L1), a positive voltage value is output to the control unit 17 from the voltmeter 5, which measures the voltage of the electrolytic capacitor 4 included in the power supply circuit 1a.

[0041] The single-phase AC power supply is not connected to the power supply circuit 1b (the positive side of the single-phase AC power supply 10a is not connected to the power supply line L2), so that a voltage value 0 is output to the control unit 17 from the voltmeter 5, which measures the voltage of the electrolytic capacitor 4 included in the power supply circuit 1b.

[0042] On the other hand, in a case where the switching power supply 100 is connected to the two-phase AC power supply 10b (in a case where the positive sides of the respective phases of the two-phase AC power supply 10b are connected to the power supply line L1 and the power supply line L2), positive voltage values ​​are output to the control unit 17 from both the voltmeter 5 that measures the voltage of the electrolytic capacitor 4 included in the power supply circuit 1a and the voltmeter 5 that measures the voltage of the electrolytic capacitor 4 included in the power supply circuit 1b.

[0043] Thus, the control unit 17 can detect whether the switching power supply 100 is connected to the single-phase AC power supply 10a or to the two-phase AC power supply 10b based on the voltage values ​​output by the respective voltmeters 5.

[0044] For example, in a case where a voltage value equal to or less than a predetermined threshold is output from any one of the voltmeters 5 included in the power supply circuit 1a and the power supply circuit 1b, it is determined that the switching power supply 100 is connected to the single-phase AC power supply 10a. For example, in a case where voltage values ​​greater than the predetermined threshold are output from all of the voltmeters 5 included in the power supply circuit 1a and the power supply circuit 1b, it is determined that the switching power supply 100 is connected to the two-phase AC power supply 10b.

[0045] As described above, the control unit 17 can determine whether the switching power supply 100 is connected to the single-phase AC power supply 10a or is connected to the two-phase AC power supply 10b using a voltmeter other than the voltmeter 5 or an ammeter.

[0046] Next, the control unit 17 performs an initial charging of the electrolytic capacitor 4 of the AC / DC converter 3 according to the determined AC power supply data.

[0047] As in Fig. 1, in a case where the switching power supply 100 is connected to the single-phase AC power supply 10a (Yes at step S100), the control unit 17 switches the switching relay 8 to the OFF state to perform the initial charging (step S101).

[0048] At the start of the flowchart, the switching relay 8 is in the ON state, and the inrush current prevention relay 14 of the inrush current prevention circuit 12 is in the OFF state, as shown in Fig. 4 shown.

[0049] The reason why the switching relay 8 is in the ON state at startup is that the switching power supply 100 is short-circuited when connected to the two-phase AC power supply 10b. The reason why the inrush current prevention relay 14 is in the OFF state at startup is that the electrolytic capacitor 4 of the AC / DC converter 3 is discharged when the AC power supply is connected, so a potential difference between the AC power supply and the electrolytic capacitor 4 is large, and accordingly, an inrush current flows into the electrolytic capacitor 4.

[0050] The inrush current prevention relay 14 is in the OFF state, so that electric power supplied from the single-phase AC power supply 10a is supplied to the power supply circuit 1a via the power supply line L1 and is supplied to the inrush current limiting circuit 13 of the inrush current prevention circuit 12.

[0051] Therefore, the charging (initial charging) of the electrolytic capacitor 4 of the power supply circuit 1a can be performed while preventing the inrush current from flowing into the power supply circuit 1a.

[0052] After the above-described control, the control unit 17 receives the voltage value of the electrolytic capacitor 4 measured by the voltmeter 5 (step S102). The control unit 17 receives the voltage value from the voltmeter 5 at a time when a predetermined time has elapsed after the control unit 17 switches the switching relay 8 to the OFF state (step S101). After the control unit 17 receives the voltage value, the flow proceeds to step S103.

[0053] Next, the control unit 17 determines whether the initial charging of the electrolytic capacitor 4 is completed by comparing the voltage value received from the voltmeter 5 with the predetermined threshold value (step S103). If the voltage value received from the voltmeter 5 is equal to or less than the threshold value (No in step S103), the flow returns to step S102.

[0054] On the other hand, in a case where the voltage value received from the voltmeter 5 is greater than the threshold value (Yes at step S103), the control unit 17 determines that the initial charging of the electrolytic capacitor 4 is completed. At this point, the control unit 17 switches the inrush current prevention relay 14 to the ON state (step S104).

[0055] The control unit 17 then performs charging (main charging) of the battery 20 while maintaining the OFF state of the switching relay 8 (step S105). In other words, in a case where the switching power supply 100 is connected to the single-phase AC power supply 10a, the control unit 17 controls the switching circuit 7 to connect the power supply circuit (the power supply circuit 1b) other than the specific power supply circuit (the power supply circuit 1a) to the specific phase (for example, the power supply line L1) corresponding to the single-phase AC power supply 10a.

[0056] By charging the battery 20 while the switching relay 8 is turned OFF, the battery 20 is charged while not only the power supply filter 2 included in the power supply circuit 1a but also the power supply filter 2 included in the power supply circuit 1b are connected to the single-phase AC power supply 10a. Thus, compared with a case where charging is performed using only the power supply filter 2 included in the power supply circuit 1a, the noise reduction performance can be improved.

[0057] The power supply filter 2 included in the power supply circuit 1b connected to the single-phase AC power supply 10a is inherently included in the switching power supply 100, so that it is not necessary to dispose a noise filter again, and there can be an advantageous effect of preventing an increase in cost and preventing an increase in the size of the device.

[0058] For example, an X capacitor or a Y capacitor is used as the power supply filter 2. The X capacitor is a capacitor that primarily eliminates differential mode noise in the switching power supply 100, and the Y capacitor is a capacitor that primarily eliminates common mode noise in the switching power supply 100. The Y capacitor is connected to a vehicle body (frame ground).

[0059] In a case of using the X capacitor or the Y capacitor as the power supply filter 2, by connecting not only the power supply filter 2 included in the power supply circuit 1a but also the power supply filter 2 included in the power supply circuit 1b to the single-phase AC power supply 10a when charging the battery 20, the capacitance of the capacitor is increased, so that the noise reduction performance can be improved.

[0060] As the power supply filter 2, a noise filter such as a core or a coil may be used instead of the capacitor. Similarly to the case of using the capacitor, the noise reduction performance can be improved in a case where the switching power supply 100 is connected to the single-phase AC power supply 10a.

[0061] On the other hand, in a case where the switching power supply 100 is connected to the two-phase AC power supply 10b (No at step S100), the control unit 17 performs an initial charging while maintaining the ON state of the switching relay 8, as shown in Fig. 3 (step S106).

[0062] Also, in a case where the switching power supply 100 is connected to the two-phase AC power supply 10b, the inrush current prevention relay 14 is in the OFF state. Thus, the electric power supplied from the two-phase AC power supply 10b is supplied to the power supply circuit 1a and the power supply circuit 1b via the power supply line L1 and the power supply line L2, and is supplied to the inrush current limiting resistor of the inrush current limiting circuit 13.

[0063] In other words, such a circuit arrangement is made that the power supply circuit 1a, the power supply circuit 1b and the inrush current limiting circuit 13 are connected between the neutral point n1 of the two-phase AC power supply 10b and the first phase (the power supply line L1) (see Fig. 3).

[0064] Thus, the charging (initial charging) of the electrolytic capacitors 4 of the power supply circuit 1a and the power supply circuit 1b can be performed while the inrush current limiting circuit 13 prevents an inrush current from flowing into the power supply circuit 1a and the power supply circuit 1b.

[0065] After the above-described control, the control unit 17 receives the voltage value of the electrolytic capacitor 4 measured by the voltmeter 5 (step S107).

[0066] Next, the control unit 17 determines whether the initial charging of the electrolytic capacitor 4 is completed by comparing the voltage value received from the voltmeter 5 with the predetermined threshold value (step S108). If the voltage value received from the voltmeter 5 is equal to or less than the threshold value (No in step S108), the flow returns to step S107.

[0067] On the other hand, in a case where the voltage values ​​received from the voltmeters 5 disposed in the power supply circuits 1a and 1b, respectively, are both greater than the threshold value (Yes at step S108), the control unit 17 determines that the initial charging of the electrolytic capacitors 4 disposed in the power supply circuits 1a and 1b, respectively, is completed. At this point, the control unit 17 switches the inrush current prevention relay 14 to the ON state (step S109).

[0068] The control unit 17 then performs charging (main charging) of the battery 20 while maintaining the ON state of the switching relay 8 (step S110).

[0069] The example of operation of the switching power supply 100 is described above.

[0070] In the present embodiment, in the switching power supply 100 compatible with the single-phase AC power supply 10a or the two-phase AC power supply 10b, the control unit 17 connects the other power supply circuit corresponding to the phase to each phase of the AC power supply, and in a case where the number of phases of the AC power supply is smaller than the number of power supply circuits, surplusly connects another power supply circuit to the specific phase.

[0071] That is, the control unit 17 controls the switch circuit 7 to connect the power supply circuit (the power supply circuit 1b) other than the specific power supply circuit (the power supply circuit 1a) corresponding to the specific phase (the power supply line L1) to the phase (the power supply line L2) corresponding to the other power supply circuit (the power supply circuit 1b) in a case where the AC power supply (the two-phase AC power supply 10b) is connected with the same number of phases as the number of power supply circuits, and to connect another power supply circuit surplus (the power supply circuit 1b) to the specific phase (the power supply line L1) in a case where the AC power supply (the single-phase AC power supply 10a) is connected with a smaller number of phases than the number of power supply circuits.

[0072] Therefore, in a case where the single-phase AC power supply 10a is connected, the switching power supply 100 can perform charging by using not only the power supply filter 2 included in the power supply circuit 1a but also the power supply filter 2 included in the power supply circuit 1b, so that the noise reduction performance can be improved. Second embodiment

[0073] Next, the following describes an example of a configuration of a switching power supply 200 according to the present embodiment. Structure of the switching power supply 200

[0074] Fig. Figure 6 is a circuit diagram illustrating an example of the arrangement of the switching power supply 200. The switching power supply 200 has a structure including three power supply circuits (the power supply circuits 1a to 1c) to be compatible with a three-phase AC power supply. Fig. 6 are the same components as those in Fig. 1 are designated by the same reference numbers and their description is not repeated.

[0075] For example, the switching power supply 200 is used for a charging device of a vehicle such as an electric vehicle and a hybrid vehicle.

[0076] The switching power supply 200 differs from the one in Fig. 1 in that the power supply circuit 1c and a switch circuit 7a are added. The power supply circuit 1c has the same arrangement as that of the power supply circuits 1a and 1b. The switch circuit 7a has the same arrangement as that of the switch circuit 7, and the switching on and off of the switching relay 8 is controlled by the control unit 17. The switch circuit 7 and the switch circuit 7a are examples of a switch circuit described in the claims.

[0077] When a switching relay 8a of the switching circuit 7a is in the OFF state, the power supply circuit is connected to the power supply line L1 branched off at the branch point n2, as shown in Fig. 6. On the other hand, when the switching relay 8a of the switching circuit 7a is in the ON state, the power supply circuit is connected to the power supply line L3.

[0078] For example, Fig. 6 illustrates a case where the switching power supply 200 is connected to the single-phase AC power supply 10a, but the switching power supply 200 may be connected to the two-phase AC power supply 10b as shown in Fig. 7, or may be connected to the three-phase AC power supply 10c, as shown in Fig. 8. The switching power supply 200 according to the present embodiment has a configuration compatible with the single-phase AC power supply 10a, the two-phase AC power supply 10b, and the three-phase AC power supply 10c.

[0079] The inrush current prevention circuit 12 is arranged closer to the AC power supply side than the junction point (connection point) n3 of the negative side line of the power supply circuit 1a, the negative side line of the power supply circuit 1b, and the negative side line of the power supply circuit 1c, and limits an inrush current.

[0080] In Fig. 5, the negative side lines of the respective power supply circuits 1a to 1c are connected to the one junction point (connection point) n3, but a first connection point at which the negative side line of the power supply circuit 1a is connected to the negative side line of the power supply circuit 1b may, for example, be different from a second connection point at which the negative side line of the power supply circuit 1b is connected to the negative side line of the power supply circuit 1c.

[0081] In this case, for example, the inrush current prevention circuit 12 is arranged closer to the AC power supply side than the first connection point and the second connection point. With this arrangement, the inrush current prevention circuit 12 does not need to be arranged for each line, and the switching power supply 200 can be downsized.

[0082] The inrush current prevention circuit 12 is not necessarily located closer to the AC power supply side than the first connection point and the second connection point, and may be located at a different position. For example, the inrush current prevention circuit 12 may be located in any of the negative-side line of the power supply circuit 1a, the negative-side line of the power supply circuit 1b, and the negative-side line of the power supply circuit 1c.

[0083] In the present embodiment, the switching circuits 7 and 7a switch between the first mode and the second mode described in the first embodiment and a third mode in which the power supply circuits 1a, 1b and 1c are driven in a case where the AC power supply is the three-phase AC power supply 10c.

[0084] The example of the arrangement of the switching power supply 200 is described above. Operation of the switching power supply 200

[0085] Next, the following describes an example of operation of the switching power supply 200 with reference to Fig. 9. Fig. Figure 9 is a flowchart illustrating an example of operation of the switching power supply 200. The operation described below begins when the AC power supply is connected.

[0086] First, the control unit 17 determines the data of the connected AC power supply (step S200). Specifically, the control unit 17 determines whether the AC power supply is the single-phase AC power supply 10a, the two-phase AC power supply, or the three-phase AC power supply.

[0087] The control unit 17 determines whether the AC power supply is the single-phase AC power supply 10a, the two-phase AC power supply 10b, or the three-phase AC power supply 10c based on a voltage value output from the voltmeter 5, which measures, for example, the voltage of the electrolytic capacitor 4.

[0088] At the start of the flowchart, the switching relays 8 and 8a are in the ON state, as shown in Fig. 8. Thus, in a case where the switching power supply 200 is connected to the single-phase AC power supply 10a (in a case where, for example, the positive side of the single-phase AC power supply 10a is connected to the power supply line L1), a positive voltage value is output to the control unit 17 from the voltmeter 5, which measures the voltage of the electrolytic capacitor 4 included in the power supply circuit 1a.

[0089] In this case, the single-phase AC power supply is not connected to the power supply circuits 1b and 1c (the positive side of the single-phase AC power supply 10a is not connected to the power supply line L2 and the power supply line L3), so a voltage value 0 is output to the control unit 17 from the voltmeter 5, which measures the voltage of the electrolytic capacitor 4 included in each of the power supply circuits 1b and 1c.

[0090] In a case where the switching power supply 200 is connected to the two-phase AC power supply 10b (in a case where the positive sides of the respective phases of the two-phase AC power supply 10b are connected to the power supply line L1 and the power supply line L2), a positive voltage value is output to the control unit 17 from the voltmeter 5 which measures the voltage of the electrolytic capacitor 4 included in each of the power supply circuits 1a and 1b.

[0091] In this case, a voltage value 0 is output to the control unit 17 from the voltmeter 5, which measures the voltage of the electrolytic capacitor 4 included in the power supply circuit 1c.

[0092] In a case where the switching power supply 200 is connected to the three-phase AC power supply 10c (in a case where the positive sides of the respective phases of the three-phase AC power supply 10c are connected to the power supply line L1, the power supply line L2, and the power supply line L3), a positive voltage value is output to the control unit 17 from the voltmeter 5 that measures the voltage of the electrolytic capacitor 4 included in each of the power supply circuits 1a, 1b, and 1c.

[0093] Thus, the control unit 17 can detect, based on the voltage value output from each of the voltmeters 5, which of the single-phase AC power supply 10a, the two-phase AC power supply 10b, or the three-phase AC power supply 10c is connected to the switching power supply 200.

[0094] For example, in a case where a voltage value equal to or less than the predetermined threshold is output from one or two of the voltmeters 5 included in the power supply circuits 1a to 1c, respectively, it is determined that the switching power supply 200 is connected to the single-phase AC power supply 10a or the two-phase AC power supply 10b. For example, in a case where voltage values ​​greater than the predetermined threshold are output from all of the voltmeters 5 included in the power supply circuits 1a to 1c, respectively, it is determined that the switching power supply 200 is connected to the three-phase AC power supply 10c.

[0095] The control unit 17 can determine which of the single-phase AC power supply 10a, the two-phase AC power supply 10b, and the three-phase AC power supply 10c is connected to the switching power supply 200 using a voltmeter other than the voltmeter 5 included in the AC / DC converter 3 or an ammeter.

[0096] Next, the control unit 17 performs an initial charging of the electrolytic capacitor 4 of the AC / DC converter 3 according to the determined AC power supply data.

[0097] In a case where the switching power supply 200 is connected to the single-phase AC power supply 10a or the two-phase AC power supply 10b (Yes at step S200), the control unit 17 switches the switching relay 8a to the OFF state to perform the initial charging, as shown in Fig. 6 or Fig. 7 (step S201). The switching relay 8 is no different from the switching relay 8a.

[0098] Thus, for example, in a case where the switching power supply 200 is connected to the single-phase AC power supply 10a, the switching relay 8 may be switched to the OFF state instead of the switching relay 8a to perform initial charging.

[0099] At the start of the flowchart, it is assumed that the switching relays 8 and 8a are in the ON state and the inrush current prevention relay 14 is in the OFF state. The reason why the switching relays 8 and 8a are in the ON state at the start is the same as the reason why the switching relay 8 is in the ON state at the start in the first embodiment, so a description thereof is not repeated. The reason why the inrush current prevention relay 14 is in the OFF state at the start is the same as that in the first embodiment. Furthermore, steps S202 to S204 are the same as steps S102 to S104.

[0100] The control unit 17 then performs charging (main charging) of the battery 20 while maintaining the OFF state of the switching relay 8a (step S205). In other words, in a case where the single-phase AC power supply 10a or the two-phase AC power supply 10b is connected to the switching power supply 200, that is, the number of phases of the connected AC power supply is smaller than the number of power supply circuits, the control unit 17 controls the switching circuit 7a to connect the surplus power supply circuit (for example, any one or both of the power supply circuits 1b and 1c) to the specified phase (for example, the power supply line L1).

[0101] In this way, by charging the battery 20 while the switching relay 8a is turned OFF, the battery 20 is charged in a state where not only the power supply filter 2 included in the power supply circuit 1a but also the power supply filter 2 included in the power supply circuit 1c are connected to the single-phase AC power supply 10a. Thus, compared with a case where charging is performed using only the power supply filter 2 included in the power supply circuit 1a, the noise reduction performance can be improved.

[0102] By charging the battery 20 while the switching relay 8a is turned OFF, the battery 20 is charged while keeping not only the power supply filter 2 included in the power supply circuit 1a but also the power supply filter 2 included in the power supply circuit 1c connected to the two-phase AC power supply 10b. Thus, compared with a case where charging is performed by connecting the two-phase AC power supply 10b to the power supply circuits 1a and 1b, the noise reduction performance can be improved.

[0103] On the other hand, in a case where the switching power supply 200 is connected to the three-phase AC power supply 10c (No at step S200), the control unit 17 performs an initial charging while maintaining the ON state of the switching relay 8, as shown in Fig. 8 (step S206).

[0104] Also, in a case where the switching power supply 200 is connected to the three-phase AC power supply 10c, the inrush current prevention relay 14 is in the OFF state, so that the electric power supplied from the three-phase AC power supply 10c is supplied to the power supply circuits 1a to 1c via the power supply lines L1 to L3 and is supplied to the inrush current limiting resistor of the inrush current limiting circuit 13.

[0105] Therefore, the charging (initial charging) of the electrolytic capacitor 4 of the power supply circuits 1a to 1c can be performed while preventing an inrush current from flowing into the power supply circuits 1a to 1c.

[0106] Steps S207 to S209 are the same as steps S107 to S109 described above. Then, at step S209, the control unit 17 turns the inrush current prevention relay 14 off and charges the battery 20 while maintaining the switching relay 8a in the on state (step S210).

[0107] The example of operation of the switching power supply 200 is described above.

[0108] In the present embodiment, in the switching power supply 200 compatible with the single-phase AC power supply 10a, the two-phase AC power supply 10b, and the three-phase AC power supply 10c, the control unit 17 connects the power supply circuit corresponding to the phase to each phase of the AC power supply, and in a case where the number of phases of the AC power supply is smaller than the number of power supply circuits, surplusly connects the other power supply circuit to the specific phase.

[0109] That is, the control unit 17 controls the switch circuit 7 to connect the power supply circuit (the power supply circuits 1b and 1c) other than the specific power supply circuit (the power supply circuit 1a) corresponding to the specific phase (the power supply line L1) to the phase (the power supply lines L2 and L3) corresponding to the other power supply circuit (the power supply circuits 1b and 1c) in a case where the AC power supply (the three-phase AC power supply 10c) is connected with the same number of phases as the number of power supply circuits, and to connect the other power supply circuit surplus (both or any one of the power supply circuits 1b and 1c) to the specific phase (the power supply line L1) in a case where the AC power supply (the single-phase AC power supply 10a and the two-phase AC power supply 10b) is connected with the smaller number of phases than the number of power supply circuits.

[0110] Therefore, in a case where the single-phase AC power supply 10a or the two-phase AC power supply 10b is connected to the switching power supply 200, charging can be performed by using not only the power supply filter 2 included in the power supply circuit 1a or 1b but also the power supply filter 2 included in the power supply circuit 1c, so that the noise reduction performance can be improved. Modification of the operation of the switching power supply 200

[0111] The switching power supply 200 can operate in Fig. 10 instead of the one shown in the second embodiment with reference to Fig. Carry out the operation described in section 6. Fig. 10 is a flowchart illustrating an operation example of the switching power supply 200 according to a modification of the second embodiment.

[0112] First, the control unit 17 determines the data of the connected AC power supply. Specifically, the control unit 17 determines whether the AC power supply is the single-phase AC power supply 10a (step S300). In this respect, the present modification differs from the second embodiment, in which it is determined whether the AC power supply is the single-phase AC power supply 10a or the two-phase AC power supply 10b.

[0113] In a case where the switching power supply 200 is connected to the single-phase AC power supply 10a (Yes at step S300), the control unit 17 switches both of the switching relays 8 and 8a to the OFF state to perform initial charging (step S301).

[0114] Therefore, even in a case where the switching power supply 200 is connected to the single-phase AC power supply 10a, the initial charging of the electrolytic capacitor 4 included in the power supply circuits 1a to 1c, respectively, can be performed.

[0115] At step S301, it is preferable to control the switching relays 8 and 8a at different timings. This is because an inrush current is increased when the switching relays 8 and 8a are switched to the OFF state simultaneously.

[0116] Steps S302 to S304 are the same as steps S202 to S304, so their description is not repeated. After the initial charging of the electrolytic capacitor 4 is completed, the inrush current prevention relay 14 is switched to the ON state (step S304).

[0117] The control unit 17 then performs charging (main charging) of the battery 20 while maintaining the OFF state of the switching relays 8 and 8a (step S305). In other words, in a case where the single-phase AC power supply 10a or the two-phase AC power supply 10b is connected to the switching power supply 200, the control unit 17 makes the inrush current prevention relay 14 of the inrush current prevention circuit 12 conductive while keeping the excess power supply circuit (for example, any one or both of the power supply circuits 1b and 1c) connected to the specific phase (the power supply line L1).

[0118] By charging the battery 20 while the switching relays 8 and 8a are turned OFF, the battery 20 is charged while keeping not only the power supply filter 2 included in the power supply circuit 1a but also the power supply filters 2 included in the power supply circuits 1b and 1c connected to the single-phase AC power supply 10a. Thus, compared with a case where charging is performed using only the power supply filter 2 included in the power supply circuit 1a, the noise reduction performance can be significantly improved.

[0119] In a case where the switching power supply 200 is not connected to the single-phase AC power supply 10a (No at step S300), it is determined whether the switching power supply 200 is connected to the two-phase AC power supply 10b (step S306).

[0120] In a case where the switching power supply 200 is connected to the two-phase AC power supply 10b (Yes at step S306), the control unit 17 switches the switching relay 8a to the OFF state to perform the initial charging while maintaining the ON state of the switching relay (step S307).

[0121] Steps S308 to S310 are the same as steps S302 to S304, so their descriptions are not repeated. After the initial charging of the electrolytic capacitor 4 is completed, the inrush current prevention relay 14 is switched to the ON state (step S310).

[0122] The control unit 17 then turns on the switching relay 8 to perform charging (main charging) of the battery 20 while maintaining the OFF state of the switching relay 8a (step S311). In other words, in a case where the switching power supply 200 is connected to the two-phase AC power supply 10b, the control unit 17 makes the inrush current prevention relay 14 of the inrush current prevention circuit 12 conductive while keeping the excess power supply circuit (for example, the power supply circuit 1c) connected to the specific phase (the power supply line L1).

[0123] In a case where the switching power supply 200 is connected to the three-phase AC power supply 10c (No at step S306), the control unit 17 performs initial charging while maintaining the ON state of the switching relays 8 and 8a (step S312).

[0124] Steps S313 to S315 are the same as steps S207 to S209. Then, at step S315, the control unit 17 turns the inrush current prevention relay 14 on and performs charging (main charging) of the battery 20 while maintaining the switching relays 8 and 8a on (step S316).

[0125] The modification of the operation of the switching power supply 200 is described above. Third embodiment

[0126] In a switching power supply 300 according to the present embodiment, a Y capacitor 2a is used for the power supply filter 2 as shown in Fig. 11. The present embodiment differs from the first embodiment and the second embodiment in that the switching relay 8 (and 8a) is turned off after the initial charging only in a case where the voltage value of the external AC power supply is equal to or less than the predetermined value. Fig. Figure 11 shows the power supply circuits (the power supply circuits 1a and 1b) arranged in two lines, but the embodiment is not limited to this. As shown in Fig. As shown in Figure 12, the power supply circuits (power supply circuits 1a to 1c) may be arranged in three lines. The following describes an example of a configuration in a case where the power supply circuits (power supply circuits 1a to 1c) are arranged in three lines.

[0127] Each of the Y capacitors 2a included in the power supply circuits (the power supply circuits 1a to 1c) is grounded in a vehicle. According to the prior art, in a case where the switching power supply is connected to the single-phase AC power supply 10a, for example, one line of the three-line power supply circuits (the power supply circuits 1a to 1c) is connected to the single-phase AC power supply 10a to charge a battery.

[0128] In a case of connecting one line (for example, the power supply circuit 1a) of the power supply circuits (the power supply circuits 1a to 1c) arranged in three lines to the positive side of the single-phase AC power supply 10a, electric power is supplied to only one ground supply line corresponding to a single Y capacitor 2a connected to the single-phase AC power supply 10a among three Y capacitors 2a included in the power supply circuits (the power supply circuits 1a to 1c).

[0129] On the other hand, in a case of connecting two lines (for example, the power supply circuits 1a and 1c) or three lines (the power supply circuits 1a, 1b and 1c) of the power supply circuits (the power supply circuits 1a to 1c) arranged in three lines, the positive side of the single-phase AC power supply 10a supplies electric power to the ground supply lines corresponding to two or three of the Y capacitors 2a connected to the single-phase AC power supply 10a, among the three Y capacitors 2a included in the power supply circuits (the power supply circuits 1a to 1c).

[0130] Thus, the total capacitance between the supply line to which the electric power of the single-phase AC power supply 10a is supplied and the ground line changes between a case of connecting one line (for example, the power supply circuit 1a) from the power supply circuits arranged in three lines (the power supply circuits 1a to 1c) to the positive side of the single-phase AC power supply 10a and a case of connecting two lines (for example, the power supply circuits 1a and 1c) or three lines (for example, the power supply circuits 1a, 1b and 1c) from the power supply circuits arranged in three lines (the power supply circuits 1a to 1c) to the positive side of the single-phase AC power supply 10a.

[0131] More specifically, the total capacitance is the capacitance of only the Y capacitor 2a in one ground supply line in a case of connecting one line (for example, the power supply circuit 1a) from the power supply circuits (the power supply circuits 1a to 1c) to the positive side of the single-phase AC power supply 10a, while the total capacitance is the capacitance of the three Y capacitors 2a in the respective three ground supply lines in a case of connecting three lines (the power supply circuits 1a, 1b and 1c) from the power supply circuits (the power supply circuits 1a to 1c) to the positive side of the single-phase AC power supply 10a.

[0132] That is, the total capacitance of the Y capacitors 2a in a case of connecting three lines (1a, 1b and 1c) from the power supply circuits (the power supply circuits 1a to 1c) to the positive side of the single-phase AC power supply 10a is three times the capacitance of the Y capacitor 2a in a case of connecting one line (for example, the power supply circuit 1a) from the power supply circuits (the power supply circuits 1a to 1c) to the positive side of the single-phase AC power supply 10a.

[0133] Similarly, in a case of connecting two lines (the power supply circuits 1a and 1c) from the power supply circuits (the power supply circuits 1a to 1c) to the positive side of the single-phase AC power supply 10a, the total capacitance of the Y capacitor 2a is twice the capacitance of the Y capacitor 2a in a case of connecting one line (for example, the power supply circuit 1a) from the power supply circuits (the power supply circuits 1a to 1c) to the positive side of the single-phase AC power supply 10a.

[0134] From the above point of view, when two lines (for example, the power supply circuits 1a and 1c) or three lines (the power supply circuits 1a, 1b and 1c) among the power supply circuits (the power supply circuits 1a to 1c) arranged in three lines are connected to the positive side of the single-phase AC power supply 10a to charge the battery 20, a leakage current (for example, a contact current) may be increased compared with the case of connecting one line (for example, the power supply circuit 1a) among the power supply circuits (the power supply circuits 1a to 1c) arranged in three lines to the positive side of the single-phase AC power supply 10a to charge the battery 20.

[0135] Furthermore, the leakage current increases in proportion to the voltage value of the external AC power supply. Thus, in a case where the voltage value of the external AC power supply is large, it may be preferable not to turn the switching relay 8 and the switching relay 8a off to perform the initial charging in some cases at step S101 in the first embodiment and step S201 in the second embodiment.

[0136] It may be preferable in some cases not to charge the battery 20 in a state where the OFF state of the switching relays 8 and 8a is maintained at step S105 in the first embodiment and step S205 in the second embodiment.

[0137] Thus, in a case where the switching power supply 300 according to the present embodiment is connected to the single-phase AC power supply 10a or the two-phase AC power supply 10b and the voltage value of the single-phase AC power supply 10a or the two-phase AC power supply 10b is equal to or less than the predetermined value (for example, 240 V), the control unit 17 connects the surplus power supply circuit (for example, the power supply circuit 1c) that does not correspond to the phase of the single-phase AC power supply 10a or the two-phase AC power supply 10b to the specified phase (for example, the power supply line L1) to perform the initial charging of the electrolytic capacitor 4.

[0138] Alternatively, in a case where the switching power supply 300 is connected to the single-phase AC power supply 10a or the two-phase AC power supply 10b and the voltage value of the single-phase AC power supply 10a or the two-phase AC power supply 10b is equal to or less than the predetermined value (for example, 240 V), the control unit 17 may connect the excess power supply circuit (for example, the power supply circuit 1c) to the specific phase (for example, the power supply line L1) to charge the battery 20 after initially charging the electrolytic capacitor 4.

[0139] In a case where the switching power supply 300 is connected to the single-phase AC power supply 10a, the switching relay 8a can also be controlled together with the switching relay 8 to switch the power supply circuit surplus (for example, the power supply circuits 1b and 1c) that do not correspond to the specific phase (for example, the power supply line L1) to connect to the specific phase (for example, the power supply line L1).

[0140] The voltage value of the AC power supply may be received by the voltmeter 5, or a voltmeter other than the voltmeter 5 may be arranged. The voltage value is output to the control unit 17, and the control unit 17 controls the switching relay 8 or the switching relay 8a based on the voltage value.

[0141] In the present embodiment, in a case where the switching power supply 300 in which the power supply filter 2 includes the Y capacitor 2a is connected to the single-phase AC power supply 10a or the two-phase AC power supply 10b and the voltage value of the single-phase AC power supply 10a is equal to or less than the predetermined value, the control unit 17 connects the other power supply circuit corresponding to the phase to each phase of the AC power supply, and in a case where the number of phases of the AC power supply is less than the number of power supply circuits, surplusly connects the other power supply circuit to the specific phase.

[0142] That is, in a case where the AC power supply (the single-phase AC power supply 10a, the two-phase AC power supply 10b) is connected with the smaller number of phases than the number of power supply circuits and the voltage value of the single-phase AC power supply 10a is equal to or less than the predetermined value, the control unit 17 controls the switch circuit 7 to connect the other power supply circuit surplus (both or any one of the power supply circuits 1b and 1c) to the certain phase (the power supply line L1).

[0143] Therefore, in a case where the single-phase AC power supply 10a or the two-phase AC power supply 10b is connected to the switching power supply 300, charging can be performed using not only the power supply filter 2 of the power supply circuit to which the AC power supply is connected, but also the power supply filter 2 included in the excess power supply circuit, so that noise reduction performance can be improved. Accordingly, the switching power supply 300 can reduce leakage current.

[0144] The embodiments of the present disclosure are described above, but the present invention is not limited to the above-described embodiments. Various modifications may be made without departing from the gist of the present invention.

[0145] For example, in the embodiments described above, a case where the power supply circuit 1a, the power supply circuit 1b, and the power supply circuit 1c are connected to the power supply line L1 (the specific phase) when performing the initial charging of the capacitor is exemplified, but the embodiment is not limited to this. For example, an arrangement may be such that the power supply circuit 1a, the power supply circuit 1b, and the power supply circuit 1c are connected to the power supply line L2 or the power supply line L3 when performing the initial charging of the capacitor.

[0146] That is, an arrangement may be such that, when performing the initial charging of the capacitor, the power supply circuits (the power supply circuits 1a to 1c) are connected between the specific phase (the power supply line L1) and the neutral point n1. The number of power supply circuits (the power supply circuits 1a to 1c) may be multiple, that is, two or more. The multi-phase AC power supply is not limited to the two-phase AC power supply 10b or the three-phase AC power supply 10c, and may have a plurality of phases equal to or greater than two.

[0147] According to the present disclosure, the performance of the noise filter can be improved without rearranging a noise filter.

[0148] While specific embodiments are described, these embodiments are presented only by way of example and are not intended to limit the scope of the invention. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; further, various omissions, substitutions, and changes may be made in the form of the methods and systems described herein without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.

Claims

[1] Switching power supply (100; 200; 300), comprising: a plurality of power supply circuits (1a, 1b; 1a, 1b, 1c) corresponding to respective phases of a multi-phase AC power supply (10b; 10c) as an external power supply, each of the power supply circuits including a filter circuit (2), a voltmeter (5) and an AC / DC converter (3), the AC / DC converter (3) being configured to convert AC power output from the filter circuit (2) into DC power, the voltmeter (5) measuring a voltage of an output capacitor included in the AC / DC converter (3); a switch circuit (7; 7, 7a) configured to switch a connection destination of another power supply circuit among the power supply circuits (1a, 1b; 1a, 1b, 1c), which is other than a specific power supply circuit corresponding to a specific phase of the external power supply, to a phase corresponding to the other power supply circuit or the specific phase; an inrush current prevention circuit (12) configured to prevent an inrush current, the inrush current prevention circuit being arranged on a power supply line on a negative side of the external power supply and at a position closer to the external power supply than a connection point to which the power supply circuits (1a, 1b; 1a, 1b, 1c) are connected, and a control unit (17) designed to control the switching circuit (7; 7, 7a) according to a number of phases of the external voltage supply connected to the switching power supply, wherein the control unit (17) is designed to connect the other power supply circuit corresponding to the phase to each phase of the external power supply connected to the switching power supply, and to connect the other power supply circuit surplus to the specific phase if the number of phases of the external power supply connected to the switching power supply is smaller than a number of the power supply circuits (1a, 1b; 1a, 1b, 1c), the control unit (17) is designed to determine the number of phases of the external power supply connected to the switching power supply on the basis of a voltage value measured by the voltmeter, the control unit (17) is designed: connect the other power supply circuit to the specific phase and de-energise a relay included in the inrush current prevention circuit to perform an initial charging of the output capacitor; and to make the relay of the inrush current prevention circuit conductive, while leaving the other power supply circuit surplus connected to the specific phase after the initial charging of the output capacitor, if the number of phases of the external power supply connected to the switching power supply is smaller than the number of power supply circuits (1a, 1b; 1a, 1b, 1c), and when the switching power supply (100, 200, 300) is connected to the single-phase AC power supply (10a) and a voltage value of the single-phase AC power supply (10a) is equal to or less than a predetermined value, the control unit (17) is configured to connect a power supply circuit from the plurality of power supply circuits that does not correspond to the phase of the single-phase AC power supply (10a) in excess to the phase of the single-phase AC power supply (10a) in order to carry out the initial charging of the output capacitor. [2] A switching power supply (100; 200; 300) according to claim 1, wherein, when a single-phase AC power supply (10a) is connected to the switching power supply, the control unit (17) is configured to connect the other power supply circuit to the specific phase corresponding to the single-phase AC power supply. [3] Switching power supply (100; 200; 300) according to claim 1 or 2, wherein the filter circuit (2) comprises an X capacitor or a Y capacitor. [4] Switching power supply (100; 200; 300) according to any one of claims 1 to 3, wherein the plurality of power supply circuits (1a, 1b; 1a, 1b, 1c) includes three or more power supply circuits (1a, 1b, 1c), and the switch circuit includes switch circuits (7, 7a) arranged for other power supply circuits besides the specific power supply circuit. [5] Switching power supply (100; 200; 300) according to claim 4, wherein the control unit (17) is designed to control the switching circuits (7, 7a) at different times. [6] A vehicle comprising: the switching power supply (100; 200; 300) according to any one of claims 1 to 5. [7] Control method performed by a switching power supply (100; 200; 300) comprising: a plurality of power supply circuits (1a, 1b; 1a, 1b, 1c) corresponding to respective phases of a multi-phase AC power supply (10b; 10c) as an external power supply, each of the power supply circuits including a filter circuit (2), a voltmeter (5), and an AC / DC converter (3), the AC / DC converter (3) being configured to convert AC power output from the filter circuit (2) into DC power, the voltmeter (5) measuring a voltage of an output capacitor included in the AC / DC converter (3); and a switch circuit (7; 7, 7a) configured to select a connection destination of another power supply circuit among the power supply circuits (1a, 1b;1a, 1b, 1c) which is other than a specific power supply circuit corresponding to a specific phase of the external power supply, to a phase corresponding to the other power supply circuit or the specific phase, an inrush current prevention circuit (12) configured to prevent an inrush current, wherein the inrush current prevention circuit is arranged on a power supply line on a negative side of the external power supply and at a position closer to the external power supply than a connection point to which the power supply circuits (1a, 1b; 1a, 1b, 1c) are connected, the control method comprising:; Controlling the switching circuit (7; 7, 7a) to connect the other power supply circuit corresponding to the phase to each phase of the external power supply connected to the switching power supply, and to connect the other power supply circuit surplus to the specific phase if a number of phases of the external power supply connected to the switching power supply is smaller than a number of the power supply circuits (1a, 1b; 1a, 1b, 1c), Determining the number of phases of the external power supply connected to the switching power supply based on a voltage value measured by the voltmeter, Connecting the other power supply circuit to the specific phase and making non-conductive a relay included in the inrush current prevention circuit to perform an initial charging of the output capacitor; and Making the relay of the inrush current prevention circuit conductive while leaving the other power supply circuit surplus connected to the specific phase after the initial charging of the output capacitor, if the number of phases of the external power supply connected to the switching power supply is smaller than the number of power supply circuits (1a, 1b; 1a, 1b, 1c), and when the switching power supply (100, 200, 300) is connected to the single-phase AC power supply (10a) and a voltage value of the single-phase AC power supply (10a) is equal to or less than a predetermined value: connecting one power supply circuit from the plurality of power supply circuits, which does not correspond to the phase of the single-phase AC power supply (10a), in excess to the phase of the single-phase AC power supply (10a) to perform the initial charging of the output capacitor.

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