Simplified DC voltage sensorless control of single-phase PFC converters in EV chargers

A novel method for controlling the output DC link voltage of a single-phase power factor correction (PFC) converter without using a DC voltage sensor for electric vehicle (EV) charging is proposed in this paper. The conventional boost PFC converter normally uses three expensive sensors, i.e., at the input voltage, the input current, and the output voltage. These sensors are used to regulate the power quality and maintain system stability. To reduce the cost and hardware complexity in the power converter, a DC voltage sensorless control using an estimator is proposed. This method utilizes the available input voltage and current signals to predict the output DC link voltage. This predicted output voltage contains an average DC component superimposed with a small ripple content at double the line frequency (2 f ). The proposed control method tracks the reference sinewave signal to maintain a high-power factor. The converter also exhibits very stable behavior under transient load variations. Simulated and experimental validation results obtained with a 1 kW prototype PFC converter are included.