Comparison between nonlinear-carrier control and average-current-mode control for PFC converters

Single phase high power factor rectification is the most frequently accomplished using a boost converter. The input current shaping approach results in low line currents harmonic distortion and a power factor close to unity at the interface between the ac line and the rectifier. Various technique are available for active current shaping, most of them are now supported by dedicated integrated circuits. Nonlinear control is one from these controls where the switch duty cycle is determined by comparing a signal derived from the main switch current with a periodic, nonlinear carrier waveform that forces the input current to follow the input line voltage. Average-current-mode control is the other regular control where the inductor current is forced to follow the input voltage. Recently nonlinear phenomena have been obvious in AC/DC converters which results in unstable regime such as period doubling and chaos. During these operating regimes, the input current distorts and therefore, breaks the operation of PFC converters. In this paper, a comparison between the two practical controls for boost PFC converter is introduced. Both techniques have tested to determine the practical limitation for stable regions. Some design guidelines are made clear for stable operation in both control techniques. Experimental results confirm simulation with good matching.