A zero voltage switching space vector modulation (ZVS-SVM) controlled three-phase boost rectifier is proposed. A branch composed of one active switch, one resonant inductor and one clamping capacitor is added to the six-switch boost rectifier. In addition, a ZVS-SVM for the rectifier is proposed. It can effectively suppress the reverse recovery process of the bridge switch anti-parallel diodes. All the switches are turned on under zero voltage condition, thus the switching loss is reduced, and electromagnetic interence can be lowered. The switching frequency of the rectifier is fixed. The auxiliary switch works at the same frequency with other switch. All the switches in the rectifier have lower voltage stress. A digital signal processor controlled 4-kW prototype is built to verify the theory. Index Terms-Electromagnetic interference (EMI), power factor correction (PFC), zero voltage switching space vector modulation (ZVS-SVM).

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SummaryWe propose a novel speed sensorless vector control method for induction motors, which is applicable to industrial drive systems.This method calculates the flux axis angular velocity and rotor speed of an induction motor from the induced voltages, without using any delay components. According to this method, the system can directly estimate an accurate motor speed, and precisely generate torque.In addition, this system can smoothly restart operation after an instantaneous power interruption.We show the validity of the proposed control method through several experiments.