A power supply circuit of a photovoltaic intelligent DC isolating switch and a photovoltaic inverter

Abstract

The utility model discloses a power supply circuit of a photovoltaic intelligent DC isolating switch and a photovoltaic inverter, and relates to the field of power electronics technology. The power supply circuit of the photovoltaic intelligent DC isolating switch is used to provide electric energy for the tripping action of the photovoltaic intelligent DC isolating switch, and the power supply circuit of the photovoltaic intelligent DC isolating switch includes a capacitor and a switch element; the first end of the capacitor is respectively connected to the external power supply and the positive access end of the photovoltaic intelligent DC isolating switch, and the second end of the capacitor is grounded; the first end of the switch element is connected to the negative access end of the photovoltaic intelligent DC isolating switch, and the second end of the switch element is connected to the second end of the capacitor; the controlled end of the switch element is connected to a remote host computer, and is used to be controlled to be in a conducting state or a disconnected state. The technical solution disclosed in the utility model can effectively avoid the impact on the operating stability of the photovoltaic inverter where the photovoltaic intelligent DC isolating switch is located when the photovoltaic intelligent DC isolating switch is tripped.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, in particular to a power supply circuit of a photovoltaic intelligent DC isolating switch and a photovoltaic inverter. Background Art

[0002] With the rapid development and popularization of photovoltaic technology, people pay more and more attention to the safety of photovoltaic systems. Among them, photovoltaic inverters are important components in photovoltaic systems, and the photovoltaic DC switches in photovoltaic inverters have also evolved from traditional manual isolation switches to photovoltaic intelligent DC isolation switches. In the actual operation of photovoltaic systems, the fault detection device of the photovoltaic system accurately detects the current signal of each photovoltaic string connected to the photovoltaic inverter through a high-precision DC sensor. When a fault is detected in the photovoltaic string, it can actively control the photovoltaic intelligent DC isolation switch corresponding to the faulty photovoltaic string to disconnect, decouple the faulty photovoltaic string from the photovoltaic inverter, and quickly issue a trip protection and active alarm to effectively disconnect the fault current, so as to effectively protect the photovoltaic string from reverse connection, current backflow and other faults, and effectively improve the safety of the photovoltaic system.

[0003] However, the photovoltaic intelligent DC disconnect switch requires a large short-term tripping energy when it is tripped. Some manufacturers' switches require up to 30W of power at the moment of tripping, but when the photovoltaic inverter is operating normally, the power required by the photovoltaic intelligent DC disconnect switch is almost zero. At present, the auxiliary power supply in the photovoltaic inverter is often used to directly power the photovoltaic intelligent DC disconnect switch. Here, the power of the auxiliary source needs to be much larger than that under normal working conditions in order to enable the photovoltaic intelligent DC disconnect switch to trip smoothly, so as to meet the stability of the photovoltaic inverter when it is tripped. However, when the photovoltaic intelligent DC disconnect switch is tripped, a large short-term impact current will be generated at the high-power auxiliary source, which is very unfavorable to the stability of the auxiliary source of the photovoltaic inverter and the auxiliary source of the main circuit of the photovoltaic inverter, and it is easy to affect the stable operation of the photovoltaic inverter. Therefore, how to reduce the impact current generated by the auxiliary source when the photovoltaic intelligent DC disconnect switch is tripped is an important problem that the photovoltaic industry urgently needs to solve. Utility Model Content

[0004] In view of this, the utility model provides a power supply circuit of a photovoltaic intelligent DC isolating switch and a photovoltaic inverter, the main purpose of which is to solve the technical problem that when the photovoltaic intelligent DC isolating switch is tripped, the impact current generated affects the operating stability of the photovoltaic inverter where the photovoltaic intelligent DC isolating switch is located.

[0005] To achieve the above-mentioned purpose, the utility model first provides a power supply circuit of a photovoltaic intelligent DC isolating switch, which is used to provide electric energy for the tripping action of the photovoltaic intelligent DC isolating switch, and the power supply circuit of the photovoltaic intelligent DC isolating switch includes a capacitor and a switch element;

[0006] The first end of the capacitor is connected to the positive electrode access end of the photovoltaic intelligent DC isolation switch and the power supply end of the external power supply, and the second end of the capacitor is grounded;

[0007] The first end of the switch element is connected to the negative electrode access end of the photovoltaic intelligent DC isolation switch, and the second end of the switch element is connected to the second end of the capacitor;

[0008] The controlled end of the switch element is connected to a remote host computer for being controlled to be in an on state or an off state.

[0009] In one embodiment of the utility model, the power supply circuit of the photovoltaic intelligent DC isolating switch also includes a first current limiting resistor; the first end of the first current limiting resistor is connected to the power supply end of the power supply, and the second end of the first current limiting resistor is respectively connected to the first end of the capacitor and the positive electrode access end of the photovoltaic intelligent DC isolating switch.

[0010] In one embodiment of the utility model, the switching element is an NPN transistor; the base of the NPN transistor is connected to the host computer, the collector of the NPN transistor is connected to the negative access terminal of the photovoltaic intelligent DC isolation switch, and the emitter of the NPN transistor is connected to the second end of the capacitor.

[0011] In one embodiment of the utility model, the switching element is a field effect transistor; the gate of the field effect transistor is connected to the host computer, the source of the field effect transistor is connected to the negative access terminal of the photovoltaic intelligent DC isolation switch, and the drain of the field effect transistor is connected to the second end of the capacitor.

[0012] In one embodiment of the utility model, the power supply circuit of the photovoltaic intelligent DC isolating switch also includes a second current limiting resistor; the first end of the second current limiting resistor is connected to the host computer, and the second end of the second current limiting resistor is connected to the gate of the field effect transistor.

[0013] In one embodiment of the utility model, the power supply circuit of the photovoltaic intelligent DC isolation switch also includes a pull-down resistor; the first end of the pull-down resistor is connected to the gate of the field effect transistor, and the second end of the pull-down resistor is connected to the second end of the capacitor.

[0014] In one embodiment of the utility model, the power supply circuit of the photovoltaic intelligent DC isolating switch also includes a trip indication relay and an alarm; the first end of the relay coil of the trip indication relay is connected to the second end of the switching element, and the second end of the relay coil is connected to the second end of the capacitor; the first end of the normally open contact of the trip indication relay is connected to the power supply end of the external power supply, and the second end of the normally open contact is connected to the alarm.

[0015] In one embodiment of the present invention, the trip indication relay is a power-off delay relay.

[0016] In one embodiment of the present invention, the capacitor is a double-layer capacitor or a pseudocapacitor.

[0017] In addition, to achieve the above-mentioned purpose, the utility model also proposes a photovoltaic inverter, including a power supply circuit of the photovoltaic intelligent DC isolation switch as described above.

[0018] The utility model provides a power supply circuit of a photovoltaic intelligent DC isolating switch and a photovoltaic inverter. When the photovoltaic intelligent DC isolating switch does not need to perform a tripping action, the external power supply, that is, the auxiliary source in the photovoltaic inverter, will charge the capacitor. Here, the capacitor in the circuit is a supercapacitor, and the auxiliary source in the photovoltaic inverter can be a low-power power supply to charge the capacitor until it is fully charged. When the relevant equipment in the photovoltaic system identifies that the photovoltaic string connected to the photovoltaic intelligent DC isolating switch has PV reverse connection, arcing and other faults, the relevant equipment can control the switch element to conduct, so that the capacitor, the photovoltaic intelligent DC isolating switch and the circuit where the switch element is located form a conduction loop, and then the photovoltaic intelligent DC isolating switch is powered from the capacitor to perform a tripping action, and disconnect the faulty photovoltaic string from the photovoltaic inverter. The technical solution provided by the present application adds a supercapacitor to the circuit, and the electric energy based on the supercapacitor provides short-term tripping energy for the photovoltaic intelligent DC isolating switch, instead of using an auxiliary source to directly power the photovoltaic intelligent DC isolating switch. Therefore, the auxiliary source in the circuit does not need a large power design margin, thereby significantly reducing the impact current generated by the auxiliary source when the photovoltaic intelligent DC isolating switch trips. Not only can the effective tripping of the photovoltaic intelligent DC isolating switch be achieved, but also the influence of the short-term impact current on the stability of the auxiliary source of the main circuit is avoided, thereby ensuring the stable operation of the photovoltaic inverter.

[0019] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0021] Figure 1 A schematic diagram of the structure of a power supply circuit of a photovoltaic intelligent DC isolating switch provided in an embodiment of the utility model is shown;

[0022] Figure 2 A schematic diagram of the structure of a power supply circuit of another photovoltaic intelligent DC isolating switch provided in an embodiment of the utility model is shown;

[0023] Figure 3 A structural schematic diagram of a power supply circuit of yet another photovoltaic intelligent DC isolating switch provided in an embodiment of the utility model is shown. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0025] In order to further explain the technical means and effects adopted by the utility model to achieve the predetermined utility model purpose, the specific implementation methods, structures, features and effects of the utility model application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

[0026] Combine the following Figures 1 to 3 A power supply circuit of a photovoltaic intelligent DC isolating switch and a photovoltaic inverter according to some embodiments of the utility model are described.

[0027] like Figure 1 As shown, an embodiment of the utility model proposes a power supply circuit of a photovoltaic intelligent DC isolating switch. Among them, the power supply circuit of the photovoltaic intelligent DC isolating switch can be set at the photovoltaic inverter, connected to the photovoltaic intelligent DC isolating switch of the photovoltaic string corresponding to the photovoltaic inverter, and used to obtain electric energy from the auxiliary source of the photovoltaic inverter to provide tripping energy for the photovoltaic intelligent DC isolating switch. Here, the photovoltaic intelligent DC isolating switch is used to connect one or more photovoltaic strings to the photovoltaic inverter, and can perform a tripping action to disconnect the connected photovoltaic strings from the photovoltaic inverter.

[0028] The power supply circuit of the photovoltaic intelligent DC isolation switch includes a capacitor C1 and a switch element; the switch element may be a circuit breaker, a contactor, or other switch elements that can be controlled to disconnect or conduct, which is not limited here. Furthermore, the capacitor C1 may be a supercapacitor such as a double-layer capacitor or a Faraday pseudo-capacitor.

[0029] Specifically, the first end of the capacitor C1 is respectively connected to the power supply end of the external power supply E and the positive access end of the photovoltaic intelligent DC isolation switch, and the second end of the capacitor C1 is grounded; here, the power supply E can be an auxiliary source of the photovoltaic inverter corresponding to the above-mentioned photovoltaic intelligent DC isolation switch, which does not require a large design power. The power supply E can provide a supply voltage of 12V, 5V and 3.3V and other voltage levels. The specific voltage level can depend on the rated shutdown voltage of the photovoltaic intelligent DC isolation switch, which is not limited here.

[0030] Furthermore, the first end of the switch element is connected to the negative electrode access terminal of the photovoltaic intelligent DC isolation switch, and the second end of the switch element is connected to the second end of the capacitor C1.

[0031] Furthermore, the controlled end of the switch element is connected to a remote host computer for being controlled to be in an on state or an off state. The host computer may be a remote photovoltaic string fault detection system, which may be connected to the photovoltaic string, collect the voltage and current of the photovoltaic string, and judge whether the photovoltaic string has a fault. When a photovoltaic string with a fault is found, a switch-on command signal may be sent to the switch element of the power supply circuit of the photovoltaic intelligent DC isolating switch corresponding to the photovoltaic intelligent DC isolating switch that connects the photovoltaic string to the photovoltaic inverter, so that the capacitor C1 in the power supply circuit of the photovoltaic intelligent DC isolating switch, the photovoltaic intelligent DC isolating switch, and the circuit where the switch element is located form a conduction loop, thereby energizing the photovoltaic intelligent DC isolating switch to perform a tripping action to disconnect the faulty photovoltaic string from the inverter.

[0032] It should be noted that the selection of capacitors and switch elements and the internal circuit connection method can be determined according to actual conditions, and this embodiment does not make specific restrictions. In addition, the connection method of each device can be determined according to the specific selection of the device, and this embodiment does not make specific restrictions. The circuit function of the power supply circuit of the photovoltaic intelligent DC isolating switch provided in this embodiment is mainly realized through the circuit connection relationship between each circuit module, and does not rely on the program module in a certain circuit module. In addition, each circuit module in the power supply circuit of the photovoltaic intelligent DC isolating switch can be realized by an analog circuit or a digital circuit, and for the circuit module that can be implanted with a program module, the realization of its module function can be realized by the program module provided by the prior art.

[0033] The power supply circuit of the photovoltaic intelligent DC isolating switch proposed in the embodiment of the utility model, when the photovoltaic intelligent DC isolating switch does not need to perform the tripping action, the external power supply, that is, the auxiliary source in the photovoltaic inverter will charge the capacitor. Here, the capacitor in the circuit is a supercapacitor, and the auxiliary source in the photovoltaic inverter can be a low-power power supply to charge the capacitor until it is fully charged. When the relevant equipment in the photovoltaic system recognizes that the photovoltaic string connected to the photovoltaic intelligent DC isolating switch has PV reverse connection, arcing and other faults, the relevant equipment can control the switch element to conduct, so that the capacitor, the photovoltaic intelligent DC isolating switch and the circuit where the switch element is located form a conduction loop, and then the photovoltaic intelligent DC isolating switch is energized to perform the tripping action and disconnect the faulty photovoltaic string from the inverter. The technical solution provided by the present application adds a supercapacitor to the circuit. The electric energy based on the supercapacitor provides short-term tripping energy for the photovoltaic intelligent DC isolating switch, so that the auxiliary source in the circuit does not need a large power design margin, thereby significantly reducing the impact current generated by the auxiliary source when the photovoltaic intelligent DC isolating switch trips. It can not only achieve effective tripping of the photovoltaic intelligent DC isolating switch, but also avoid the influence of short-term impact current on the stability of the auxiliary source of the main circuit, thereby ensuring the stable operation of the photovoltaic inverter and reducing the loss of the photovoltaic power station.

[0034] In one embodiment, Figure 2 As shown, the power supply circuit of the photovoltaic intelligent DC isolation switch also includes a first current limiting resistor R1; specifically, the first end of the first current limiting resistor R1 is connected to the power supply end of the energy supply E, and the second end of the first current limiting resistor R1 is respectively connected to the first end of the capacitor C1 and the positive access end of the photovoltaic intelligent DC isolation switch. Here, when the power supply circuit of the photovoltaic intelligent DC isolation switch is in operation, the energy supply E outputs electric energy, and the first current limiting resistor R1 is set in the circuit so that the energy supply E can slowly charge the capacitor C1 until the electric energy of the capacitor C1 is fully charged. The embodiment provided by the present application can limit the current of the energy supply based on the first current limiting resistor, so that the supercapacitor in the circuit can be charged normally, and the charging capacity of the supercapacitor is improved, so as to ensure that when the photovoltaic intelligent DC isolation switch needs to be tripped, the electric energy in the supercapacitor can support the photovoltaic intelligent DC isolation switch to perform the tripping action, and ensure the power supply capacity of the power supply circuit of the photovoltaic intelligent DC isolation switch to the photovoltaic intelligent DC isolation switch.

[0035] In one embodiment, the switching element is an NPN transistor; the base of the NPN transistor is connected to the host computer, the collector of the NPN transistor is connected to the negative access terminal of the photovoltaic intelligent DC isolating switch, and the emitter of the NPN transistor is connected to the second end of the capacitor. In the actual working process, if it is necessary to make the photovoltaic intelligent DC isolating switch perform a tripping action, the host computer only needs to send a voltage to the base of the NPN transistor to turn on the NPN transistor, so that the capacitor provides tripping power for the photovoltaic intelligent DC isolating switch, so that the photovoltaic intelligent DC isolating switch performs a tripping action. The embodiment provided by the present application can control whether the capacitor provides tripping power for the photovoltaic intelligent DC isolating switch based on the NPN transistor as a switching element, which significantly reduces the hardware cost of the power supply circuit of the photovoltaic intelligent DC isolating switch.

[0036] In one embodiment, Figure 3 As shown, the switch element is a field effect transistor Q3; the gate of the field effect transistor Q3 is connected to the host computer, the source of the field effect transistor Q3 is connected to the negative access terminal of the photovoltaic intelligent DC isolation switch, and the drain of the field effect transistor Q3 is connected to the second end of the capacitor C1. Here, the field effect transistor Q3 can be a P-channel field effect transistor, and the conduction command signal can be a high-level signal.

[0037] In the actual working process, if it is necessary to make the photovoltaic intelligent DC isolating switch perform a tripping action, the host computer only needs to send a voltage to the gate of the field effect transistor Q3 to turn on the field effect transistor Q3, so that the photovoltaic intelligent DC isolating switch obtains the tripping power from the capacitor C1, so that the photovoltaic intelligent DC isolating switch performs a tripping action. The embodiment provided by the present application can control whether the capacitor provides the tripping power for the photovoltaic intelligent DC isolating switch based on the field effect transistor as a switching element, and also significantly reduces the hardware cost of the power supply circuit of the photovoltaic intelligent DC isolating switch.

[0038] In one embodiment, Figure 3 As shown, the power supply circuit of the photovoltaic intelligent DC isolating switch also includes a second current limiting resistor R2; specifically, the first end of the second current limiting resistor R2 is connected to the host computer, and the second end of the second current limiting resistor R2 is connected to the gate of the field effect transistor Q3. Here, the second current limiting resistor R2 can also achieve current limiting, and can also play a role in voltage division, which is used to drive the field effect transistor Q3 to turn on or off. The embodiment provided by the present application can receive the turn-on signal of the host computer based on the second current limiting resistor, drive the field effect transistor to turn on, and improve the driving ability of the power supply circuit of the photovoltaic intelligent DC isolating switch to the field effect transistor.

[0039] In one embodiment, Figure 3 As shown, the power supply circuit of the photovoltaic intelligent DC isolation switch also includes a pull-down resistor R3; the first end of the pull-down resistor R3 is connected to the gate of the field effect transistor Q3, and the second end of the pull-down resistor R3 is connected to the second end of the capacitor C1. In the embodiment provided by the present application, by setting a pull-down resistor in the circuit, when the host computer sends a high-level conduction command signal to the gate of the field effect transistor, the conduction signal obtained from the host computer can be clamped at a high level, thereby improving the anti-interference ability of the circuit.

[0040] In one embodiment, the power supply circuit of the photovoltaic intelligent DC disconnect switch further includes a trip indication relay and an alarm; here, the trip indication relay can be a power-off delay relay.

[0041] Specifically, the first end of the relay coil of the trip indication relay is connected to the second end of the switch element, and the second end of the relay coil is connected to the second end of the capacitor; when the capacitor provides energy to the photovoltaic intelligent DC isolation switch, current will flow through the relay coil in an instant. Furthermore, the first end of the normally open contact of the trip indication relay is connected to the power supply end of the external power supply, and the second end of the normally open contact is used to connect to a remote alarm. The alarm can be an alarm device installed in a remote control center room or a photovoltaic power station duty room, and the external power supply is used to provide the working voltage required for the alarm device to send out an alarm message.

[0042] Specifically, when the current flows through the relay coil in an instant, the normally open contact corresponding to the relay coil will be turned on. At the same time, because the trip indication relay is a power-off delay relay, after the relay coil loses power, the normally open contact of the trip indication relay will still be turned on for a period of time, so that the external power supply normally opens the contact to power the alarm device, so that the alarm device sends an alarm prompt message within a period of time. The embodiment provided by the present application can send an alarm prompt message by the alarm when the photovoltaic intelligent DC isolation switch performs a tripping action, so as to remind relevant staff that there is a tripping phenomenon of the photovoltaic intelligent DC isolation switch caused by a photovoltaic string fault, so that relevant staff can perform further troubleshooting.

[0043] On the other hand, an embodiment of the utility model provides a photovoltaic inverter, including a power supply circuit of the photovoltaic intelligent DC isolating switch as described above. Specifically, an auxiliary power supply in the photovoltaic inverter can be connected to the first end of the capacitor and the positive access end of the photovoltaic intelligent DC isolating switch, and a system for running photovoltaic string fault detection in the photovoltaic inverter can be connected to the controlled end of the switch element to control the power supply circuit of the photovoltaic intelligent DC isolating switch to drive the photovoltaic intelligent DC isolating switch to perform a tripping operation.

[0044] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A power supply circuit of a photovoltaic intelligent DC isolating switch, used to provide electric energy for the tripping action of the photovoltaic intelligent DC isolating switch, characterized in that: The power supply circuit of the photovoltaic intelligent DC isolating switch includes a capacitor and a switch element; The first end of the capacitor is connected to the positive electrode access end of the photovoltaic intelligent DC isolation switch and the power supply end of the external power supply, and the second end of the capacitor is grounded; The first end of the switch element is connected to the negative electrode access end of the photovoltaic intelligent DC isolation switch, and the second end of the switch element is connected to the second end of the capacitor; The controlled end of the switch element is connected to a remote host computer for being controlled to be in an on state or an off state.

2. The power supply circuit of the photovoltaic intelligent DC isolating switch according to claim 1, characterized in that: The power supply circuit of the photovoltaic intelligent DC isolating switch also includes a first current limiting resistor; The first end of the first current limiting resistor is connected to the power supply end of the energy supply, and the second end of the first current limiting resistor is respectively connected to the first end of the capacitor and the positive electrode access end of the photovoltaic intelligent DC isolation switch.

3. The power supply circuit of the photovoltaic intelligent DC isolating switch according to claim 1 is characterized in that: The switch element is an NPN transistor; The base of the NPN transistor is connected to the host computer, the collector of the NPN transistor is connected to the negative access terminal of the photovoltaic intelligent DC isolation switch, and the emitter of the NPN transistor is connected to the second end of the capacitor.

4. The power supply circuit of the photovoltaic intelligent DC isolating switch according to claim 1, characterized in that: The switch element is a field effect transistor; The gate of the field effect transistor is connected to the host computer, the source of the field effect transistor is connected to the negative electrode access terminal of the photovoltaic intelligent DC isolation switch, and the drain of the field effect transistor is connected to the second end of the capacitor.

5. The power supply circuit of the photovoltaic intelligent DC isolating switch according to claim 4, characterized in that: The power supply circuit of the photovoltaic intelligent DC isolating switch also includes a second current limiting resistor; The first end of the second current limiting resistor is connected to the host computer, and the second end of the second current limiting resistor is connected to the gate of the field effect transistor.

6. The power supply circuit of the photovoltaic intelligent DC isolating switch according to claim 5, characterized in that: The power supply circuit of the photovoltaic intelligent DC isolating switch also includes a pull-down resistor; A first end of the pull-down resistor is connected to the gate of the field effect transistor, and a second end of the pull-down resistor is connected to the second end of the capacitor.

7. The power supply circuit of the photovoltaic intelligent DC isolating switch according to claim 1, characterized in that: The power supply circuit of the photovoltaic intelligent DC isolating switch also includes a trip indication relay and an alarm; A first end of the relay coil of the trip indication relay is connected to the second end of the switch element, and a second end of the relay coil is connected to the second end of the capacitor; A first end of the normally open contact of the trip indication relay is connected to a power supply end of an external power supply, and a second end of the normally open contact is connected to the alarm.

8. The power supply circuit of the photovoltaic intelligent DC isolating switch according to claim 7, characterized in that: The trip indication relay is a power-off delay relay.

9. The power supply circuit of the photovoltaic intelligent DC isolating switch according to claim 1, characterized in that: The capacitor is an electric double layer capacitor or a pseudo capacitor.

10. A photovoltaic inverter, characterized in that: A power supply circuit comprising the photovoltaic intelligent DC isolating switch as claimed in any one of claims 1 to 9.

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