Multiloop Control With Two Duty-Ratio Feedforward Current Loops via Sensing Series-Capacitor Current for Voltage Doubler PFC Converter

In this article, the voltage doubler PFC converter with two boost inductors and one series-capacitor is studied. Only when both symmetrical duty ratios are larger than 0.5, the conventional multiloop control with one inner current loop and one voltage loop can be directly applied to the voltage doubler PFC converter due to its topology asymmetry. To remove this duty-ratio limit, the multiloop control with two duty-ratio feedforward current loops is proposed where the series-capacitor current is sensed to reconstruct two inductor currents. It follows that the number of sensor in the proposed control is three equal to the number of sensor in the conventional multiloop control. The proposed method is implemented in a field programmable gate array chip. The provided simulation and experimental results validate the effectiveness.