Sungrow Power Supply Co., Ltd.

Cheng Zhang

Lei Tao

Jie Ding

Haiyan Zou

Taotao Xu

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 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

Cheng Zhang