A unity power factor front-end rectifier with hysteresis current control

A three-phase front-end rectifier capable of sustaining sinusoidal input currents in phase with their corresponding input phase voltages, and performing a wide dc link voltage regulation, is analyzed and presented in this paper. It makes use of three bidirectional switches between the rectifier ac side and de link. An output power estimator, a dc link voltage regulator and a hysteresis current controller are applied in the proposed control algorithm to obtain and track the reference currents. This control algorithm, based on hysteresis current control technique, can enable the proposed rectifier-inverter ac motor drive to function within a wide output power range and large input inductance variations, yielding low current harmonics and unity power factor. Theoretical results of its analysis are verified initially through digital simulation, and confirmed by using an experimental prototype.