A Variable Feedback Control for Single Phase VIENNA Rectifiers at Non-Load Condition

It is hard for a VENNIA rectifier to operate at non-load condition, where the converter usually triggers the over voltage protection. To solve this problem, a variable feedback control is proposed to limit the duty ratio of the switches at non-load condition. The control method proposed leads to greatly reduced output voltage ripple of the rectifier at non-load condition, where the output voltage can be tightly controlled. Both the operating principle and the parameter design guidelines of this method are analyzed in detail. Finally, experimental results are presented to verify the control.