Dual comparison one cycle control for single phase AC to DC converters

Classical control and one cycle control of current are popular methods used to generate PWM pulses in active rectifiers for ac-dc power conversion. One cycle control has lower control complexity and can be implemented using simple analog circuits and digital circuits, when compared with the classical approach. However, it also suffers from distortion in input current when the converter is lightly loaded and steady state dc offset in input current under all load conditions. In this paper a new dual comparison one cycle control is proposed which overcomes the above limitations. The proposed control strategy makes use of two comparators which compares sensed input current and inverted sensed input current with a saw-tooth carrier to generate gating signals for switching devices. Detailed simulation studies are carried to validate the viability of the proposed control.