An improved burst-mode control for VIENNA rectifiers to mitigate DC voltage ripples at light load

Due to the unidirectional conduction of the diode, a VIENNA rectifier will be operated at over-voltage-protection (OVP) mode as long as the load is light enough. And the output voltage is usually used as the trigger variable in the existing burst-mode control to hold the output, which inducing a very large voltage ripple, otherwise the double line frequency pulsation may lead to false trigging. An improved burst-mode control is proposed with analyzing the dual loop control principle of the rectifier in dq frame in detail, where the output of the voltage regulator is employed as the trigger. The control proposed leads to greatly reduced output voltage ripple of the rectifier and works well under grid distortion. Experimental and simulation results are given to verify the effectiveness and advantages of the proposed method.