A general three-phase PFC controller. I. For rectifiers with a parallel-connected dual boost topology

摘要

A general constant-frequency power-factor-correction (PFC) controller is proposed for three-phase rectifiers with parallel-connected dual-boost topologies. This paper shows that unity fundamental power factor and low current distortion in all three phases can be realized by one-cycle control of a linear combination of the inductor currents using one integrator with reset along with a few logic components. This new extension of one-cycle control provides the core PFC function to the dual-boost topologies and the logical circuit rotates the PFC function in three phases. It does not require multipliers, used in many other control approaches, to scale the current reference according to the output power level. In each 60/spl deg/ of AC line cycle, only two switches are switched at high frequency; therefore the switching losses are significantly reduced. All switches are switched at low current, which results in reduced current ratings. This control method is simple and general. It is applicable to three-phase rectifiers that can be decoupled into parallel-connected dual-boost topologies by slight modification of the logic circuit. This control method is verified by theoretical analysis and experimental results. The proposed controller is ready to be integrated into a three-phase PFC control chip.