METHOD AND DEVICE FOR SWITCHING OPERATION MODE OF A FIVE-LEVEL INVERTER

摘要

A method for switching an operation mode of a five-level inverter and a 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 of the five-level inverter 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 of the five-level inverter required when the five-level inverter is connected to a power grid; switching, after the operation mode of the five-level inverter is switched to the first three-level operation mode, the operation mode of the five-level inverter 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 of the five-level inverter 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. According to the provided method, the junction temperature of a switching device still operating after the operation mode of the five-level inverter is switched from the five-level operation mode to the three-level operation mode is reduced.