Control method for improving the response of single‐phase continuous conduction mode boost power factor correction converter

Abstract

Continuous conduction mode power factor correction AC–DC converters are widely employed as the front stage in power supplies with medium or high output power. The second-order reactive input power in single-phase systems causes second-order ripple in the DC-link voltage. The speed of voltage regulation is thus limited by the second-order frequency in seeking to achieve low distorted input current. This study presents a fast second-order voltage estimation method, wherein an integrator is used for the estimation of second-order voltage ripple to obtain rapid voltage feedback without ripple and thereby cope with the limitations imposed by the second-order frequency. This approach greatly expands the bandwidth of the voltage control loop beyond the second-order frequency while reducing the total harmonic distortion associated with the input current. This also makes it possible to reduce the DC capacitance to reduce costs. The authors opted for full digital control using a TI F28335 DSP IC, in conjunction with feedback plus feedforward control to facilitate the design of the current loop. A feedback current corrector is used to reduce distortion associated with the input current over a wide load range. The effectiveness of the proposed control method was confirmed with some simulation and experimental results.