Pulse Train Control Strategy for CCM Boost PFC Converter With Improved Dynamic Response and Unity Power Factor

Pulse train (PT) control strategy for the boost power factor correction (PFC) converter operating in the continuous conduction mode (CCM) is proposed and studied in this article. Average current mode (ACM) control is usually utilized for the CCM boost PFC converter. The ACM-controlled PFC converter suffers from poor dynamic response, because its voltage control loop has to be designed with low bandwidth to minimize the effect of low-frequency output voltage ripple on the current control loop. Different from ACM control, the voltage control loop and current control loop of the PT-controlled PFC converter are decoupled, and thus the effect of low-frequency output voltage ripple on the current control loop is eliminated. Besides, PT modulation is utilized in the proposed controller to regulate the inductor current to follow the current reference. Thus, both high power factor and fast dynamic response can be achieved. The operation principle of the PT-controlled CCM boost PFC converter is analyzed, and a 300-W prototype is built to verify the analysis results. The experimental results show that power factor of the PT-controlled PFC converter is higher than 0.998 and the dynamic response is significantly improved.