Digital implementation of a unity-power-factor constant-frequency DCM boost converter

A DSP implementation of digital control for constant-frequency, unity-power-factor, and discontinuous-conduction-mode boost rectifier is described. By employing variable-duty-cycle control, the power factor of over 0.99 is achieved in the entire universal line-voltage range (90-264 V). In addition, the transient response of the rectifier is optimized by utilizing a nonlinear PI-controller with anti windup that is independently optimized for U.S. line-voltage range (90-132 V) and for European line-voltage range (180-264 V) and by temporarily increasing the bandwidth of the control loop during transients. The performance of the proposed DSP control was verified on a 100-kHz, 400-W unity-power-factor rectifier prototype