Fundamental frequency parabolic PWM controller for lossless soft-switching boost power factor correction

In this paper, the fundamental frequency (50 Hz) parabolic pulse width modulation controller for the soft-switching boost power factor correction is presented. The soft-switch is achieved by using a simple commutation circuit with no auxiliary active switches. To control the operation of the boost switch in continuous conduction current mode (CCM), the new control strategy is obtained. The new control strategy is a development of the traditional instantaneous current control mode, which in commercial is popularly applied to input power factor correction. The switch duty ratio is determined by comparing a signal derived from the sensed inductor current with the generated fundamental frequency parabolic waveform. As a result, the input current waveform follows in phase with the input line voltage. The multiplier/divider in the voltage feedback loop is not required. The principle of operation is explained and analyzed, and simulation results of the new controller are included.