A predictive switching modulator for current mode control of high power factor boost rectifier

In this paper, a new variation of current mode control for high power factor operation of boost rectifier is presented. The general features are no input voltage sensing, no use of multiplier, and no inner loop current regulator. It therefore follows the same control structure as that of the linear peak current mode control and the nonlinear carrier control. However, it implements a different switching law for the modulator that extends the range of continuous conduction mode of operation. The switching principle of the modulator is predictive, as the actual current equals the reference current at the end of each switching period. The no. of reset integrators required in this modulator for generation of the carrier waveform is two. The steady-state stability analysis of the boost rectifier with the proposed predictive switching modulator (PSM) is presented in this paper. A low-frequency small-signal model of the boost rectifier switched by the PSM is developed for evaluation of the control transfer function. Experimental results on a 400-W boost rectifier prototype are presented.