High Power Factor in Three-phase Voltage Source Pulse-Width Modula- tion Rectifier Based on Direct Power Control

Abstract: The conventional pulse-width modulation rectifier has the low power factor and more sensors to detect the voltage and current of alternating current side. The traditional direct power control method possesses the defect of unfixed switching frequency. A new method based on three-phase voltage source pulse-width modulation rectifier with high power factor based on direct power control is proposed in this paper. With the analysis of the formation mechanism of the switch table, the stationary coordinate is divided into 12 vectors to optimize the input voltages. Virtual flux estimator is introduced to replace voltage sensors. Instantaneous power theory is used to calculate the estimated virtual flux active and reactive power with outer voltage and inner power loop control mode. The direct power control strategy of space vector modulation is introduced to provide the fixed switching frequency on pulse-width modulation. The experimental results show that the direct power control system has good dynamic response, so as to achieve active power and reactive power control, which ensures that the input side of the unity power factor control. It is illustrated that this method can achieve higher power factor and total lower harmonic disturbance than the conventional current control strategy.