Flipped conversion circuit and photovoltaic power generation system

A photovoltaic power generation system, comprising at least one flipped conversion circuit, a plurality of photovoltaic strings, and an inverter circuit, wherein:

• the plurality of photovoltaic strings are connected to an input unit in the flipped conversion circuit;
• and an output unit in the flipped conversion circuit is connected to the inverter circuit;
• the flipped conversion circuit is configured to convert first voltages that are output by the plurality of photovoltaic strings into second voltages, wherein the output unit outputs the second voltage;
• and
• an output terminal of the inverter circuit is connected to a power grid, to convert the second voltage into an alternating current voltage and provide the alternating current voltage to the power grid;
• and
• the flipped conversion circuit comprises a first connection end, a second connection end, a third connection end, a half-bridge switch unit, an output capacitor unit, a resonant unit, a series diode unit, an energy storage switch unit, an input unit, an output unit, and a controller, wherein:
• the half-bridge switch unit comprises N switch devices, and N is an even number, wherein the half-bridge switch unit is connected between the first connection end and the second connection end;
• the series diode unit is connected between the second connection end and the third connection end;
• the output capacitor unit is connected to two ends of the series diode unit in parallel;
• the input unit is connected between the first connection end and the second connection end;
• the output unit is connected between the first connection end and the third connection end;
• the energy storage switch unit comprises at least one switch device and a first diode, wherein the at least one switch device is connected to the first diode in series;
• the resonant unit comprises a first capacitor and a first inductor, wherein a first end of the first inductor is connected to the half-bridge switch unit, a second end of the first capacitor is connected to the series diode unit, and a second end of the first inductor is connected to a first end of the first capacitor;
• one end of the energy storage switch unit is connected between the half-bridge switch unit and the series diode unit, and the other end is connected to the second end of the first inductor;
• and
• the controller is configured to convert, by controlling the switch device in the half-bridge switch unit and the switch device in the energy storage switch unit to be turned on or turned off, a first voltage that is input by the input unit into a second voltage, wherein the output unit outputs the second voltage.