A power supply fast switching system based on photovoltaic storage direct-flexible mode

Abstract

The utility model discloses a power supply fast switching system based on a photovoltaic storage direct-flexible mode, wherein the system includes a load and a plurality of power supply circuits for supplying power to the load, wherein a static switching switch for controlling the on-off of each power supply circuit and a detection circuit for monitoring the voltage value of each power supply circuit are provided between each power supply circuit and the load, and a control circuit is provided between the static switching switch and the detection circuit, and the control circuit controls the on-off of each power supply circuit through the static switching switch according to the voltage value monitored by the detection circuit. The utility model solves the problem in the existing multi-power supply system that diodes are used for switching between the multi-power supply circuits, so that the power grid power supply circuit and the photovoltaic energy storage power supply circuit are not completely electrically isolated.

Description

Technical Field

[0001] The utility model relates to the technical field of energy management, and in particular to a power supply fast switching system based on a photovoltaic storage direct-flexible mode. Background Art

[0002] In the power supply system, in order to achieve the "dual carbon" goal, the photovoltaic storage direct flexible technology came into being. This technology integrates photovoltaic power generation, energy storage devices, DC power distribution and flexible power consumption. On the basis of realizing distributed photovoltaic consumption, it adopts multiple power supply circuits (photovoltaic energy storage power supply circuit, public power grid power supply circuit) to power the load to achieve efficient and stable power supply to ensure the normal operation of the load. However, diodes are usually used to switch between multiple power supply circuits, such as Figure 1 As shown, although the diode has the characteristic of reverse shutdown, in actual use, the diode may be reversely broken down, causing current backflow, resulting in incomplete electrical isolation between multiple power supply circuits, and the two circuits cannot be completely independent, posing certain operation and maintenance risks. Utility Model Content

[0003] Purpose of the utility model: The purpose of the utility model is to provide a power fast switching system based on the photovoltaic storage direct-flexible mode.

[0004] Technical solution: To achieve the above-mentioned purpose, the utility model describes a power fast switching system based on the photovoltaic storage direct-flexible mode, including a load and multiple power supply circuits for supplying power to the load, wherein a static switching switch for controlling the on and off of each power supply circuit and a detection circuit for monitoring the voltage value of each power supply circuit are provided between each power supply circuit and the load, and a control circuit is provided between the static switching switch and the detection circuit, and the control circuit controls the on and off of each power supply circuit through the static switching switch according to the voltage value monitored by the detection circuit.

[0005] Among them, the multiple power supply circuits include a circuit of a grid unit composed of a public grid, a transformer and an AC / DC converter, and a circuit of a photovoltaic energy storage unit composed of photovoltaic components and photovoltaic converters as well as energy storage components and energy storage converters in parallel.

[0006] Wherein, the detection circuit is arranged in parallel at the voltage output terminal V of the power grid unit. i1 and the voltage output terminal V of the photovoltaic energy storage unit i2 .

[0007] Among them, the output voltage of the public power grid voltage is first stepped down by a transformer, and then converted into 750V DC by an AC / DC converter and connected to a 750V DC bus; the output voltage of the photovoltaic module is stepped up by a photovoltaic converter, converted into 750V DC and connected to a 750V DC bus; the output voltage of the energy storage module is stepped up by an energy storage converter, converted into 750V DC and connected to a 750V DC bus. The 750V DC bus is connected to a DC converter to step down the 750V DC to 220V DC to supply power to multiple groups of loads.

[0008] There are two groups of controlled static switching switches, including a switch 1 connected in series to the voltage output end of the grid unit and a switch 2 connected to the voltage output end of the photovoltaic energy storage unit.

[0009] The switch 1 and the switch 2 each include a positive IGBT and a negative IGBT, wherein the positive IGBT controls the conduction and cutoff of the unit loop, and the negative IGBT prevents current from flowing from the load to the unit loop.

[0010] The control loop receives the V i2 Value is judged, when V i2 When the voltage is less than the set voltage, the control circuit sends a gate voltage signal to switch 1 and switch 2, causing switch 2 to be disconnected and switch 1 to be turned on. At this time, the public grid supplies power to the load. i2 When it is greater than or equal to the set voltage, the control circuit sends a gate voltage signal to switch 1 and switch 2, turning on switch 2 and disconnecting switch 1, and the photovoltaic energy storage unit supplies power to the load.

[0011] Beneficial effects: The utility model has the following advantages: 1. The system integrates the three power sources of the public power grid, photovoltaic power generation and energy storage to supply power to the load, and utilizes the detection circuit, the control circuit and the static switching switch including the positive and negative IGBT to effectively control the conduction and cutoff of each power circuit and prevent the reverse flow of current, thus solving the problem of incomplete electrical isolation caused by the switching of multiple power circuits by diodes, and at the same time improving the power switching speed and the reliability and safety of the system;

[0012] 2. In this system, photovoltaic modules and energy storage modules serve as the main power supply for the load, and the public power grid serves as the backup power supply, which improves energy utilization efficiency while ensuring stable power supply for the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram showing the design of switching between multiple power supply circuits using diodes;

[0014] Figure 2 This is the system topology diagram in the optical storage direct-flexible mode;

[0015] Figure 3 This is the topology diagram of the power supply fast switching system based on the photovoltaic storage direct-flexible mode;

[0016] Figure 4 This is the voltage detection topology diagram of the power supply fast switching system based on the photovoltaic storage direct-flexible mode;

[0017] Figure 5 This is a schematic diagram of the static switching switch circuit structure. DETAILED DESCRIPTION

[0018] The technical solution of the utility model is described in detail below in conjunction with the embodiments and drawings.

[0019] like Figure 2 As shown in the figure, it is a system topology diagram in the photovoltaic storage direct-flexible mode. The utility model designs a power supply fast switching system based on this mode, such as Figure 3 and 4 As shown, the power rapid switching system includes multiple power supply circuits, detection circuits, control circuits, and static switching switches for supplying power to loads.

[0020] Among them, the various power supply circuits include the circuit of the grid unit composed of the public power grid, the transformer and the AC / DC converter, the circuit of the photovoltaic energy storage unit composed of the photovoltaic module and the photovoltaic converter, and the energy storage module and the energy storage converter in parallel, wherein the output voltage of the public power grid is first stepped down by the transformer, and then converted into 750V DC by the AC / DC converter and connected to the 750V DC bus; the output voltage of the photovoltaic module is stepped up by the photovoltaic converter, and then converted into 750V DC and connected to the 750V DC bus; the output voltage of the energy storage module is stepped up by the energy storage converter, and then converted into 750V DC and connected to the 750V DC bus. The 750V DC bus is connected to the DC converter to step down the 750V DC to 220V DC, and supplies power to multiple groups of loads.

[0021] The detection circuit is connected in parallel to the voltage output terminal (V i1 ), the voltage output terminal of the photovoltaic energy storage unit (V i2 ) to detect the output voltage of the two unit loops in real time. The detection process is: first use a resistor to divide the unit loop to obtain a required linear voltage value, then use a follower and an integrator to send the linear voltage to a linear optocoupler for isolation, and then use an integrator and a follower to output the final voltage value.

[0022] The detection circuit sends the detected voltage value to the control circuit, and the control circuit judges the voltage value of each circuit to control the on and off of the static switching switch. The controlled static switching switch consists of two groups, switch 1 connected in series at the voltage output end of the grid unit and switch 2 connected in series at the voltage output end of the photovoltaic energy storage unit.

[0023] like Figure 5 As shown, the switch 1 and switch 2 both use two IGBTs (a positive IGBT and a negative IGBT) to form a switch, wherein the positive IGBT can control the conduction and cutoff of the unit circuit. IGBT is a semiconductor device. During the IGBT driving process, the control circuit will send a corresponding gate voltage signal to switch 1 or switch 2 according to the detected voltage value. When the gate voltage signal is positive, the IGBT is turned on and the current can flow; when the gate voltage is negative or zero, the IGBT channel is disconnected and the current stops flowing; the negative IGBT can prevent the current from flowing from the load to the unit circuit, that is, to achieve the reverse blocking function. This device helps to achieve electrical isolation between the power supply circuit and the load.

[0024] In this system, the photovoltaic components and energy storage components serve as the main power supply for the load, and the public grid serves as the backup power supply. That is, when the load is working normally, the photovoltaic energy storage unit where the photovoltaic components and energy storage components are located will supply power to the load (first powered by the photovoltaic components, and if the photovoltaic components cannot supply power, then powered by the energy storage components). The detection circuit will detect V i2 The voltage value is sent to the control loop, and the control loop responds to the received V i2 When V i2 When the voltage is less than the set voltage, it is considered that the photovoltaic energy storage unit has a fault and loses power. At this time, the control circuit sends a gate voltage signal to switch 1 and switch 2, causing switch 2 to be disconnected and switch 1 to be turned on. At this time, the public grid supplies power to the load. i2 When the voltage value is greater than or equal to the set voltage, the photovoltaic energy storage unit fault is restored. At this time, the control circuit sends a gate voltage signal to switch 1 and switch 2, turning on switch 2 and disconnecting switch 1. At this time, the photovoltaic energy storage unit where the photovoltaic components and energy storage components are located continues to supply power to the load.

Claims

1. A power supply fast switching system based on a photovoltaic storage direct-flexible mode, characterized in that: The system includes a load and multiple power supply circuits for supplying power to the load, wherein a static switching switch for controlling the on / off of each power supply circuit and a detection circuit for monitoring the voltage value of each power supply circuit are provided between each power supply circuit and the load, and a control circuit is provided between the static switching switch and the detection circuit, and the control circuit controls the on / off of each power supply circuit through the static switching switch according to the voltage value monitored by the detection circuit; The multiple power supply circuits include a circuit of a power grid unit and a circuit of a photovoltaic energy storage unit; the detection circuit is arranged in parallel at the voltage output terminal V i1 and the voltage output terminal V of the photovoltaic energy storage unit i2 The static switching switch is divided into two groups, including switch 1 connected in series to the voltage output end of the grid unit and switch 2 connected to the voltage output end of the photovoltaic energy storage unit; The control loop receives V i2 Value is judged, when V i2 When the voltage is less than the set voltage, the control circuit disconnects switch 2 and turns on switch 1. At this time, the public grid supplies power to the load. i2 When it is greater than or equal to the set voltage, the control circuit turns on switch 2 and turns off switch 1, and the photovoltaic energy storage unit supplies power to the load.

2. The power supply fast switching system based on the photovoltaic storage direct-flexible mode according to claim 1 is characterized in that: The multiple power supply circuits include a circuit of a grid unit composed of a public grid, a transformer and an AC / DC converter, and a circuit of a photovoltaic energy storage unit composed of a photovoltaic component and a photovoltaic converter, and an energy storage component and an energy storage converter in parallel.

3. The power supply fast switching system based on the photovoltaic storage direct-flexible mode according to claim 2 is characterized in that: The output voltage of the public power grid is first stepped down by a transformer, and then converted into 750V DC by an AC / DC converter and connected to a 750V DC bus; the output voltage of the photovoltaic module is stepped up by a photovoltaic converter, converted into 750V DC and connected to a 750V DC bus; the output voltage of the energy storage module is stepped up by an energy storage converter, converted into 750V DC and connected to a 750V DC bus, and the 750V DC bus steps down the 750V DC to 220V DC by connecting a DC converter to supply power to multiple groups of loads.

4. The power supply fast switching system based on the photovoltaic storage direct-flexible mode according to claim 1 is characterized in that: The switch 1 and the switch 2 each include a positive IGBT and a negative IGBT, wherein the positive IGBT controls the conduction and cutoff of the unit loop, and the negative IGBT prevents current from flowing from the load to the unit loop.

5. The power supply fast switching system based on the photovoltaic storage direct-flexible mode according to claim 1 is characterized in that: The control loop receives V i2 Value is judged, when V i2 When the voltage is less than the set value, the control circuit sends a gate voltage signal to switch 1 and switch 2, causing switch 2 to be disconnected and switch 1 to be turned on. At this time, the public grid supplies power to the load. i2 When it is greater than or equal to the set voltage, the control circuit sends a gate voltage signal to switch 1 and switch 2, turning on switch 2 and disconnecting switch 1, and the photovoltaic energy storage unit supplies power to the load.

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