CN220896345U - Switching circuit and energy storage power supply circuit - Google Patents

Abstract

The present application relates to a switching circuit and an energy storage power supply circuit. The switching circuit comprises a converter and at least one relay switching circuit connected with the converter, wherein the relay switching circuit comprises a relay circuit; the relay circuit comprises at least two relays, each relay comprises a contact circuit and a coil, the coils of the at least two relays are connected in series and then connected into the same relay power supply circuit, so that the coils of the at least two relays are simultaneously powered through the relay power supply circuit, and the switch circuit can reduce the overall power consumption of the circuit.

Description

Switching circuit and energy storage power supply circuit

Technical Field

The application relates to the field of circuits, in particular to a switch circuit and an energy storage power supply circuit.

Background

The energy storage power supply has a large number of relays and has high requirement on the idle load power consumption.

In the prior art, in order to reduce the power consumption of the relay, the series resistor is generally connected in the relay coil power supply loop in series to reduce the power consumption of the switching circuit.

However, although conventional series resistance schemes may reduce relay power consumption, the series resistance also introduces additional power consumption and the effect of reducing the overall power consumption of the circuit is not ideal.

Disclosure of utility model

In view of the foregoing, it is desirable to provide a switching circuit and an energy storage power supply circuit with low power consumption.

In a first aspect, the present application provides a switching circuit comprising: the relay switch circuit comprises a relay circuit; the relay circuit comprises at least two relays, wherein the relays comprise contact circuits and wire packages, and the wire packages of the at least two relays are connected in series and then connected into the same relay power supply circuit, so that the wire packages of the at least two relays can be simultaneously powered through the relay power supply circuit.

In one embodiment, the relay switch circuit comprises a relay circuit; or the relay switch circuit comprises at least two relay circuits connected in parallel.

In one embodiment, the relay power supply circuit comprises a first power supply source and a first driving circuit which are connected in series, and the first driving circuit can be turned on and turned off.

In one embodiment, the relay power supply circuit comprises a first relay power supply circuit and a second relay power supply circuit which are connected in parallel, and the voltage output by the first relay power supply circuit is larger than the voltage output by the second relay power supply circuit; in the process of switching on at least two relays, the first relay power supply circuit independently supplies power for the coils of the at least two relays simultaneously; after the at least two relays are turned on, the second relay power supply circuit independently supplies power to the coils of the at least two relays simultaneously.

In one embodiment, the voltage output by the first relay power supply circuit is twice the voltage output by the second relay power supply circuit.

In one embodiment, the first relay power supply circuit comprises a second power supply source, a second driving circuit and a first diode which are mutually connected in series, and the second relay power supply circuit comprises a third power supply source, a third driving circuit and a second diode which are mutually connected in series; the second driving circuit is conducted in the process that at least two relays are turned on, and is turned off after at least two relays are turned on; the third driving circuit is conducted in the process of switching on at least two relays and after switching on at least two relays; a first diode that allows current to pass when both the second driving circuit and the third driving circuit are turned on; the second diode is turned off when the second driving circuit and the third driving circuit are both turned on, and allows current to pass when the third driving circuit is turned on alone.

In one embodiment, the switching circuit comprises a first relay switching circuit connected in series between the dc power source and the input of the converter.

In one embodiment, the switching circuit further comprises a second relay switching circuit connected in series between the output of the converter and the off-grid load.

In one embodiment, the switching circuit further comprises a third relay switching circuit connected in series between the off-grid load and the ac grid.

In a second aspect, the present application provides an energy storage power supply circuit comprising a switching circuit as described in any one of the first aspects above.

The switching circuit, the converter and at least one relay switching circuit connected with the converter, wherein the relay switching circuit comprises a relay circuit; the relay circuit comprises at least two relays, wherein the relays comprise contact circuits and wire packages, and the wire packages of the at least two relays are connected in series and then connected into the same relay power supply circuit, so that the wire packages of the at least two relays can be simultaneously powered through the relay power supply circuit. In this way, the coils of the relay are connected in series, the relay power supply circuit is shared, the power consumption of the whole circuit can be reduced due to the fact that the coils of the relay are connected in series and divided, and compared with a conventional series resistance voltage division scheme, no extra power consumption is introduced.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the related art, the drawings that are required to be used in the embodiments or the related technical descriptions will be briefly described, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

FIG. 1 is a switching circuit in one embodiment;

FIG. 2 is a schematic diagram of a switching circuit according to another embodiment;

FIG. 3 shows a switching circuit according to another embodiment;

FIG. 4 shows a switching circuit according to another embodiment;

fig. 5 shows a switching circuit according to another embodiment.

Detailed Description

The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It will be understood that the terms first, second, etc. as used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, a first resistance may be referred to as a second resistance, and similarly, a second resistance may be referred to as a first resistance, without departing from the scope of the application. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

It is to be understood that in the following embodiments, "connected" is understood to mean "electrically connected", "communicatively connected", etc., if the connected circuits, modules, units, etc., have electrical or data transfer between them.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and/or the like, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Also, the term "and/or" as used in this specification includes any and all combinations of the associated listed items.

The energy storage power supply is generally a power supply with higher battery capacity and higher charge and discharge current, the relay of the energy storage power supply is composed of a coil and a contact circuit, the circuit on the driving side of the coil and the circuit on the closing side of the contact circuit are absolutely isolated, but because the inherent physical defect of the relay consumes a large amount of power, namely the relay is used as a device based on magnetic field energy, the relay needs current to excite the coil, the current means dissipation power and heating, and the energy storage power supply has high requirement on no-load power consumption, so that the overall power consumption of the circuit needs to be reduced.

In the prior art, in order to reduce the power consumption of the relay, a series resistor is generally connected in a power supply loop of the relay coil in series to reduce the power consumption of the switching circuit, for example, the impedance of the relay coil is 100 ohms, the rated voltage is 12V, and the power consumption of the coil is 1.44W in normal operation. In order to reduce the power consumption, 100 ohm resistors are connected in series to the coil, so that the actual power supply of the coil is half of the voltage, the power consumption of the coil is reduced to 0.36W, the power consumption of the added series resistors is also 0.36W, the total power consumption is 0.72W, and the total power consumption is reduced by half compared with that of the total power consumption without the series resistors.

However, although conventional series resistance schemes may reduce relay power consumption, the series resistance also introduces additional power consumption and the effect of reducing the overall power consumption of the circuit is still undesirable.

Based on this, it is necessary to propose a switching circuit with low power consumption.

In one exemplary embodiment, as shown in fig. 1, a switching circuit is provided that includes a current transformer and at least one relay switching circuit coupled to the current transformer, the relay switching circuit including a relay circuit.

The relay circuit comprises at least two relays K1 and K2, wherein the relays comprise contact circuits and coils, and the coils of the at least two relays are connected in series and then connected into the same relay power supply circuit so as to supply power to the coils of the at least two relays simultaneously through the relay power supply circuit.

Optionally, the relay is an electronic control device, which has a control system (input loop) and a controlled system (output loop), is generally applied to an automatic control circuit, and is used for controlling the on-off of the circuit by sensing the change of input current, and the relay is a switch control mode for controlling larger current and higher voltage by using smaller current and lower voltage, and plays roles of automatic regulation, safety protection, circuit switching and the like in the circuit.

One side of the relay is a ground control pin, and the other side is a normally open end, a normally closed end and a common end, and the normally closed end is connected with the common end when no power is supplied, and the normally open end is connected with the common end after power is supplied, so that the relay is equivalent to a switch. Besides the contact circuit and the coil, the relay may further comprise a magnetic circuit and a reaction spring, wherein after the relay is electrified, the coil generates electromagnetic attraction to drive the armature in the magnetic circuit to attract, so that the normally closed and normally open contact circuits generate action change, and after the relay is powered off, the reaction spring helps the armature and the contact circuits to recover to an initial state.

As shown in fig. 1, the relays K1 and K2 are respectively connected in series in the energy storage converter loop, the coils of the relays are connected in series, the driving circuit and the power supply are shared, the coils of the relays are connected in series and divided, the voltage on each coil of the relays is reduced, and then the total power consumption of the relays is reduced. For example, each relay coil resistor is 100 ohms, the power supply voltage VCC is 12V, if two coils are independently powered, the power consumption of each relay coil is 1.44W, the total power consumption of the two relays is 2.88W, if the method of reducing the power consumption by series resistors in the prior art is adopted, the power consumption of a single relay coil is 0.36W, the power consumption of a single current limiting resistor is 0.36W, the total power consumption is 1.44W, if the switching circuit in the embodiment is adopted, the coils of the two relays are connected in series and then connected into the same relay power supply circuit, under the steady state condition, the power consumption of each relay coil is 0.36W, and the total power consumption of the two relay coils is 0.72W.

The switching circuit comprises a converter and at least one relay switching circuit connected with the converter, wherein the relay switching circuit comprises a relay circuit. The relay circuit comprises at least two relays, the relays comprise contact circuits and wire packages, the wire packages of the at least two relays are connected in series and then connected into the same relay power supply circuit, so that the wire packages of the at least two relays are simultaneously powered through the relay power supply circuit, the wire packages of the at least two relays are connected in series and then divided, and the actual power supply on each wire package is at least half of the power supply voltage, so that the total power consumption of the energy storage power supply relay can be obviously reduced.

In one exemplary embodiment, as shown in fig. 1, the relay switch circuit may optionally include a one-way relay circuit based on the above embodiment; alternatively, as shown in fig. 2, the relay switch circuit includes at least two relay circuits connected in parallel.

Optionally, the relay power supply circuit includes a first power supply VCC and a first driving circuit connected in series, and the first driving circuit may be turned on and off.

Optionally, the relay switch circuit in fig. 1 includes a relay circuit, the relay circuit includes two relays K1 and K2, the coil of the relay is connected in series and then connected to the same relay power supply circuit, the power supply circuit includes a first power supply and a first driving circuit a connected in series, where the first driving circuit may be simply represented by a triode, when the switch of the relay needs to be controlled to be turned on, signals the input end of the first driving circuit a of the relay, the triode is turned on, then the relay coil circuit is electrified, the relays K1 and K2 are turned on simultaneously, and the total voltage of the relay coil is VCC.

Because the power of the energy storage inverter is larger, two relays are required to be connected in parallel at the switch position of each relay, as shown in fig. 2, the relay switch circuit comprises two relay circuits connected in parallel, one relay circuit comprises two relays K3 and K4, the two relays are connected in parallel, the other relay circuit comprises two relays K5 and K6, and the two relays are also connected in parallel. Optionally, the parallel connection of the relays means that the contact circuits of the relays are connected in parallel, the coils of the relays are connected in series, that is, in fig. 2, the contact circuits of K3 and K4 in one relay circuit are connected in parallel, the coils are connected in series, and the same relay power supply circuit is connected, wherein the power supply circuit comprises a first power supply source and a first driving circuit B which are connected in series, and the total voltage of the coils of the relays K3 and K4 is VCC; the contact circuits of K5 and K6 in the other relay circuit are connected in parallel, the wire packages are connected in series, and the same relay power supply circuit is connected in, wherein the power supply circuit comprises a first power supply and a first driving circuit C which are connected in series, and the total voltage of the wire packages of the relays K5 and K6 is VCC.

The relay switch circuit comprises a relay circuit or at least two relay circuits connected in parallel, wherein the relay power supply circuit comprises a first power supply and a first driving circuit which are connected in series, and the first driving circuit can be turned on and turned off. Therefore, after the coils of the relays are connected in series, the actual power supply on each coil of the same relay power supply circuit is changed into at least half of the power supply voltage, so that the total power consumption of the energy storage power supply relay can be obviously reduced, and meanwhile, if the switch position of each relay is replaced by two relays which are connected in parallel, the switch performance can be improved under the condition that the energy storage inverter is higher in power.

In an exemplary embodiment, as shown in fig. 3, the relay power supply circuit may optionally include a first relay power supply circuit and a second relay power supply circuit connected in parallel, where the voltage VCC2 output by the first relay power supply circuit is greater than the voltage VCC3 output by the second relay power supply circuit; in the process of switching on at least two relays, the first relay power supply circuit independently supplies power for the coils of the at least two relays simultaneously; after the at least two relays are turned on, the second relay power supply circuit independently supplies power to the coils of the at least two relays simultaneously.

Optionally, the voltage VCC2 output by the first relay power supply circuit is twice the voltage VCC3 output by the second relay power supply circuit.

That is, when the voltage of VCC2 is 2 times that of VCC3, relays K1 and K2 are respectively started according to the rated voltage, and are maintained with low voltage after the starting operation, that is, relays K1 and K2 are started with high voltage, and maintained with low voltage, so that the original switching flight time of the switching device of the relay is maintained, and the low power consumption in the maintenance stage is maintained.

The switching flight time is a time from the closed state to the open state of the contact circuit of the relay or a time from the open state to the closed state of the contact circuit of the relay, and the switching flight time becomes long at a low voltage, that is, the switching operation becomes slow.

The relay power supply circuit comprises a first relay power supply circuit and a second relay power supply circuit which are connected in parallel, wherein the voltage output by the first relay power supply circuit is greater than the voltage output by the second relay power supply circuit; in the process of switching on at least two relays, the first relay power supply circuit independently supplies power for the coils of the at least two relays simultaneously; after the at least two relays are turned on, the second relay power supply circuit independently supplies power to the coils of the at least two relays simultaneously. Therefore, the relay is started according to rated voltage, and low voltage is used for maintaining after the starting action, so that the original switching flight time of a switching device of the relay is maintained, and the overall power consumption of a switching circuit is reduced.

In an exemplary embodiment, as shown in fig. 3, optionally, on the basis of the above embodiment, the first relay power supply circuit includes a second power supply, a second driving circuit a, and a first diode D1 connected in series with each other, and the second relay power supply circuit includes a third power supply, a third driving circuit B, and a second diode D2 connected in series with each other.

The second driving circuit A is conducted in the process that at least two relays are turned on, and is turned off after at least two relays are turned on; the third driving circuit B is conducted in the process of turning on at least two relays and after the at least two relays are turned on; a first diode D1 that allows current to pass when both the second driving circuit a and the third driving circuit B are turned on; the second diode D2 is turned off when both the second driving circuit a and the third driving circuit B are turned on, and allows a current to pass when the third driving circuit B is turned on alone.

The first diode D1 and the second diode D2 can prevent the short circuit of the two direct current power supplies of the second power supply and the third power supply and release the highest voltage. For example, when the relays K1 and K2 need to be controlled to be turned on, signals are sent to the second driving circuit a and the third driving circuit B at the same time, since the output voltage VCC2 of the second power supply is greater than the output voltage VCC3 of the third power supply, the second diode D2 is turned off by receiving the reverse bias voltage, and the first diode D1 is turned on by receiving the forward voltage, so when the control signals are sent simultaneously at the end of the second driving circuit a and the end of the third driving circuit B, only the first diode D1 is turned on, the output voltage VCC2 of the second power supply acts, and the voltage of the output voltage VCC3 of the third power supply is blocked by the second diode D2, and at this time, the total voltage of the relay package is VCC2; after the switch of the relay is turned on, the control signal of the second driving circuit A is removed, and the total voltage of the relay coil is VCC3.

The first relay power supply circuit comprises a second power supply, a second driving circuit and a first diode which are mutually connected in series, wherein the second relay power supply circuit comprises a third power supply, a third driving circuit and a second diode which are mutually connected in series, and the second driving circuit is conducted in the process that at least two relays are turned on and turned off after at least two relays are turned on; the third driving circuit is conducted in the process that at least two relays are turned on and after at least two relays are turned on; the first diode allows current to pass when the second driving circuit and the third driving circuit are both conducted; the second diode is turned off when both the second driving circuit and the third driving circuit are turned on, and allows current to pass when the third driving circuit is turned on alone. Thus, when the second driving circuit and the third driving circuit are signaled at the same time, the high voltage is ensured to act, and the low voltage acts after the relay is turned on, namely, the relay is started according to the rated voltage, and the low voltage is used for maintaining after the starting action, so that the original switching flight time of a switching device of the relay is maintained, and the overall power consumption of the switching circuit is reduced.

In an exemplary embodiment, as shown in fig. 4, the switching circuit may optionally include a first relay switching circuit connected in series between the dc power source and the input terminal of the converter, based on the above embodiment.

The first relay switch circuit comprises a relay circuit, the relay circuit comprises at least two relays K11 and K12, the wire packages of the relays K11 and K12 are connected in series and then connected into the same relay power supply circuit, the relay power supply circuit comprises a first power supply source and a first driving circuit A, the power supply source of the first power supply source is VCC, and the relays K11 and K12 are respectively connected in series on the positive electrode and the negative electrode of the direct current power supply and the current transformer.

Optionally, the switching circuit further includes a second relay switching circuit, and the second relay switching circuit is connected in series between the output end of the converter and the off-grid load R1.

The second relay switch circuit comprises a relay circuit, the relay circuit comprises at least two relays K13 and K14, the wire packages of the relays K13 and K14 are connected in series and then connected into the same relay power supply circuit, the relay power supply circuit comprises a first power supply source and a first driving circuit B, the power supply source of the first power supply source is VCC, the relays K13 and K14 are connected between the converter and the off-grid load R1 and are respectively connected in series on a live wire and a zero wire of an alternating current output end.

Optionally, the switching circuit further comprises a third relay switching circuit connected in series between the off-grid load R1 and the ac grid.

The third relay switch circuit comprises a relay circuit, the relay circuit comprises at least two relays K15 and K16, the wire packages of the relays K15 and K16 are connected in series and then connected into the same relay power supply circuit, the relay power supply circuit comprises a first power supply source and a first driving circuit C, the power supply source of the first power supply source is VCC, the relays K15 and K16 are connected between an off-grid load R1 and an alternating current power grid, and the relays K15 and K16 are connected in series on a live wire and a zero wire of an alternating current output end respectively.

Under the grid connection condition, the switches of the relays K11-K16 are closed, 6 relays are arranged, and under the off-grid condition, the switches of the relays K11-K14 are closed, and 4 relays are arranged. For example, the resistance of each relay coil is 100 ohms, the power supply voltage VCC is 12V, if no power reduction measures are adopted, namely, a contact circuit of a relay and a coil share one relay power supply and a relay control circuit in parallel connection, or a separate power supply and a relay control circuit are arranged, the total power consumption of a relay coil under the grid connection condition is 8.64W, and the total power consumption of a relay coil under the off-grid condition is 5.76W. After the relays are connected in series in the manner of the embodiment, that is, the voltage of each relay coil becomes 6V, the total power consumption of the relay coil is 2.16W in the case of grid connection, and the total power of the relay coil is 1.44W in the case of off-grid connection.

As shown in fig. 5, since the power of the energy storage inverter is larger, two relays are required to be connected in parallel at each switching position, that is, the relay switching circuit in the switching circuit shown in fig. 5 includes at least two relay circuits connected in parallel, at this time, each two parallel relay wire packages are connected in series and then connected to the same relay power supply circuit, and the power supply circuit includes a first power supply and a first driving circuit. Alternatively, the parallel connection of two relays means that the contact circuits of the relays are connected in parallel, and the coils of the relays are connected in series.

Optionally, similar to fig. 4, the switching circuit shown in fig. 5 includes a first relay switching circuit connected in series between the dc power source and the input terminal of the converter, where the relays K21 and K22 are connected in parallel, i.e., the K21 and K22 contact circuits are connected in parallel, the coil is connected in series, and the first power source and the first driving circuit A1 are shared, and the relays K31 and K32 are connected in parallel, i.e., the K31 and K32 contact circuits are connected in parallel, and the coil is connected in series, and the first power source and the first driving circuit A4 are shared.

Optionally, the switching circuit includes a second relay switching circuit, where the relays K23 and K24 are connected in parallel, that is, the contact circuits of K23 and K24 are connected in parallel, and the wire package is connected in series, so as to share the first power supply and the first driving circuit A2, and the relays K33 and K34 are connected in parallel, that is, the contact circuits of K33 and K34 are connected in parallel, and the wire package is connected in series, so as to share the first power supply and the first driving circuit A5.

Optionally, the switch circuit further includes a third relay switch circuit, where the relays K25 and K26 are connected in parallel, that is, the contact circuits of the relays K25 and K26 are connected in parallel, and the coil is connected in series, so as to share the first power supply and the first driving circuit A3, and the relays K35 and K36 are connected in parallel, that is, the contact circuits of the relays K35 and K36 are connected in parallel, and the coil is connected in series, so as to share the first power supply and the first driving circuit A6.

Under the grid connection condition, the switches of the relays K21-K26, K31 and K36 are closed, 12 relays are arranged, and under the off-grid condition, the switches of the relays K21-K24 and K31-K34 are closed, and 8 relays are arranged. For example, the resistance of each relay coil is 100 ohms, the power supply voltage VCC is 12V, if no power reduction measures are adopted, namely, a contact circuit of a relay and a coil share one relay power supply and a relay control circuit in parallel connection, or a separate power supply and a relay control circuit are arranged, the total power consumption of a relay coil under the grid connection condition is 17.28W, and the total power consumption of a relay coil under the off-grid condition is 11.52W. After the relay is connected in series with the wire package according to the manner in the above embodiment, that is, the voltage of each relay coil becomes 6V, the total power consumption of the relay coil is 4.32W in the case of grid connection, and the total power of the relay coil is 2.88W in the case of off-grid connection.

The relay switch circuit connects the coils of at least two relays in series and then is connected to the same relay power supply circuit, so that the voltage of the coils of the relays can be reduced, the power consumption of the switch circuit is reduced, and no extra power consumption is introduced.

In an exemplary embodiment, the tank power supply circuit includes a switching circuit as described in any of the switching circuit embodiments described above.

In the description of the present specification, reference to the term "some embodiments," "other embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples merely represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the present application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of the application should be assessed as that of the appended claims.

Claims (10)

1. A switching circuit, characterized in that the switching circuit comprises a current transformer and at least one relay switching circuit connected with the current transformer, the relay switching circuit comprising a relay circuit;

The relay circuit comprises at least two relays, each relay comprises a contact circuit and a coil, and the coils of the at least two relays are connected in series and then connected into the same relay power supply circuit, so that the coils of the at least two relays are simultaneously powered through the relay power supply circuit.

2. The switching circuit of claim 1, wherein the relay switching circuit comprises one of the relay circuits; or alternatively

The relay switch circuit comprises at least two paths of relay circuits which are connected in parallel.

3. The switching circuit of claim 1, wherein the relay power supply circuit comprises a first power supply and a first drive circuit in series, the first drive circuit being on and off.

4. The switching circuit of claim 1, wherein the relay power supply circuit comprises a first relay power supply circuit and a second relay power supply circuit connected in parallel, the voltage output by the first relay power supply circuit being greater than the voltage output by the second relay power supply circuit;

In the process that the at least two relays are turned on, the first relay power supply circuit independently supplies power to the coils of the at least two relays simultaneously;

after the at least two relays are turned on, the second relay power supply circuit independently supplies power to the coils of the at least two relays simultaneously.

5. The switching circuit of claim 4, wherein the voltage output by the first relay power supply circuit is twice the voltage output by the second relay power supply circuit.

6. The switching circuit of claim 4, wherein the first relay power supply circuit comprises a second power supply, a second driving circuit, and a first diode in series with each other, and the second relay power supply circuit comprises a third power supply, a third driving circuit, and a second diode in series with each other;

The second driving circuit is conducted in the process that the at least two relays are turned on, and is turned off after the at least two relays are turned on;

The third driving circuit is conducted in the process that the at least two relays are turned on and after the at least two relays are turned on;

The first diode allows current to pass when the second driving circuit and the third driving circuit are both conducted;

The second diode is turned off when both the second driving circuit and the third driving circuit are turned on, and allows current to pass when the third driving circuit is turned on alone.

7. The switching circuit according to any one of claims 1 to 6, wherein the switching circuit comprises a first relay switching circuit connected in series between a dc power supply and an input of the converter.

8. The switching circuit of claim 7, further comprising a second relay switching circuit connected in series between the output of the converter and an off-grid load.

9. The switching circuit of claim 8, further comprising a third relay switching circuit connected in series between the off-grid load and an ac power grid.

10. A tank power supply circuit comprising a switching circuit as claimed in any one of claims 1 to 9.