Switching Loss Reduction Method for Instantaneous Reactive Power Compensator in Three-Phase Rectifier System

This article discusses a switching loss reduction method for an instantaneous reactive power compensator (IRPC) of a rectifier system that consists of a three-phase synchronous rectifier and a buck converter. The compensator generates a compensating current to suppress the instantaneous reactive power produced by the rectifier, resulting in a sinusoidal three-phase grid current. Zero-voltage switching (ZVS) and discontinuous pulsewidth modulation are used to reduce the switching power loss caused by the high peak of the compensating current in the compensator. A new dead-time compensation method is developed based on switching current estimation to reduce the harmonic distortion of the grid current. A 4.5-kW experimental setup was used to verify the effectiveness of the proposed methods. These methods are found to improve the grid current with a total harmonic distortion (THD) of around 3%; and a peak efficiency of 99.2%