A Non-Linear Voltage Controller for Grid Voltage Sensor-Less Power Factor Correction Converters

In this paper, a grid voltage sensor-less control scheme for an AC-DC power factor correction converter using a non-linear voltage controller is proposed. The conventional PFC converters, used in EV battery chargers, electric drive systems, and computer power supplies, require a grid voltage sensor in order to operate at unity power factor. By using the proposed non-linear control method, the grid voltage sensor, and Phase Locked Loop (PLL) are not required for unity power factor operation of the PFC converter. The proposed grid voltage sensor-less control scheme also provides an additional degree of freedom (a), for controlling the transient response of the converter and its effect on the same in terms of peak overshoot and settling time for DC-link voltage is reviewed and analyzed. The mathematical equation for the grid current drawn by a PFC converter using the proposed control scheme is also derived and using it, the effect of circuit parameters on the power factor of the converter can be predicted. With the proposed control scheme, the system's overall cost, size, and weight are reduced, making it more reliable, less complex, and cost-effective. The proposed control scheme is simulated in MATLAB-Simulink for steady-state and transient conditions, and some hardware experiment results are also included.