Sungrow Power Supply Co., Ltd.

Haiyan Zou

Lei Tao

Jie Ding

Taotao Xu

Cheng Zhang

Nianan Pan

Jigui Feng

A method and device for modulating a five-level inverter, and a photovoltaic system are provided. The method includes: acquiring a voltage command value Vcmd of a phase bridge; controlling a first and a fourth switching devices to be switched on alternately when Vcmd&#x2265;VPos+Vthrs; controlling the first and a third switching devices to be switched on alternately when VPos&#x2212;Vthrs&#x2264;Vcmd&#x3c;VPos+Vthrs; controlling the fourth and the third switching devices to be switched on alternately when 0&#x2264;Vcmd&#x3c;VPos&#x2212;Vthrs; controlling the third and a fifth switching devices to be switched on alternately when &#x2212;VNeg+Vthrs&#x2264;Vcmd&#x3c;0; controlling the third and a second switching devices to be switched on alternately when &#x2212;VNeg&#x2212;Vthrs&#x2264;Vcmd&#x3c;&#x2212;VNeg+Vthrs; controlling the fifth and the second switching devices to be switched on alternately when Vcmd&#x3c;&#x2212;VNeg&#x2212;Vthrs

Method and device for modulating a five-level inverter, and photovoltaic system

A charging and discharging system, a charging and discharging method, and a photovoltaic power generation system are provided. The charging and discharging system includes: a unidirectional converter, a unidirectional switch, an energy storage device and a controller; where an input terminal of the unidirectional converter is connected to an output terminal of a photovoltaic device of a photovoltaic power generation system to which the charging and discharging system is applied, and an output terminal of the unidirectional converter is connected to an input terminal of the energy storage device; the unidirectional switch is connected between an output terminal of the energy storage device and an input terminal of a bidirectional inverter of the photovoltaic power generation system to which the charging and discharging system is applied; the controller is connected to the unidirectional converter, the unidirectional switch, the energy storage device and the bidirectional inverter.

Charging and discharging system and method, and photovoltaic power generation system

A method and device for switching an operation mode of a five-level inverter are provided. The method includes: determining a first three-level operation mode as a three-level operation mode to be switched to from a five-level operation mode in a case that a PV input voltage is higher than a bridge line-line voltage command value; switching, after the operation mode is switched to the first three-level operation mode, the operation mode from the first three-level operation mode to a second three-level operation mode, in a case that a junction temperature of a switching device operating in the first three-level operation mode exceeds a first preset value; and switching the operation mode from the second three-level operation mode to the first three-level operation mode in a case that the junction temperature of a switching device operating in the second three-level operation mode exceeds a second preset value.

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Anhui, China

Haiyan Zou