METHOD FOR PRE-CHARGING A CASCADE CONVERTER AND CASCADE CONVERTER

摘要

The present application provides a method for pre-charging a cascade converter and a cascade converter. The cascade converter includes a main transformer, multiple power units, a control unit and a precharge unit. Power units connected with the precharge unit are a first power unit group, and other power units are a second power unit group. The control unit controls first switch set in the precharge unit to be turned on, and low-voltage AC power supply in the precharge unit performs pre-charging for a bus capacitor through an inverter circuit in the first power unit group. When a voltage of the bus capacitor reaches a first voltage threshold, the control unit controls a rectifier circuit in the first power unit group to work to magnetize the main transformer, thereby performing pre-charging for bus capacitors in the second power unit group.