Three-phase PWM synchronous rectifiers without line-voltage sensors

A line-voltage-sensorless control for three-phase pulse-width-modulated (PW M) synchronous rectifiers is presented. A line synchronisation and unity po wer factor control are described. Indirect synchronisation without sensing the line voltage allows a standard vector-controlled inverter to be used as a synchronous rectifier without requiring any additional hardware. Further more. the line synchronisation can be operated properly under line-voltage distortion or notching and line-frequency variation. It is shown via experi mental results that the proposed controller gives good performance for the synchronous rectifier.