Vector control of PWM rectifier based on a novel virtual flux observer

Aimed at the precision of flux observer in virtual flux oriented vector control (VFOC) of PWM rectifier, low-pass filter adopted in conventional virtual grid flux to substitute the pure integrator to least the DC drift would conduce error of amplitude and phase angle. A new virtual flux observer with low-pass filter compensation link is proposed. The simulation results of VFOC control system are compared based on the new and conventional flux observer. The dynamic error caused by low-pass filter is diminished and the new flux observer can effectively restrain the saturation and DC drift while the phase and amplitude errors can be compensated completely. The precision of virtual flux estimation has been improved. The simulation and experimental outcome confirmed the validity and feasibility of the proposed control strategy.