A Novel PWM Pulse Modifying Method for Reconstructing Three-Phase AC Currents from DC Bus Currents of Inverter

摘要

A novel PWM pulse modifying method for DC bus current detection has been developed to reduce acoustic noise and distortion. DC bus current detection needs wide pulse durations to reconstruct three AC currents. PWM pulse modifying methods have been proposed to expand short pulse durations at low modulation. However, harmonic currents caused by modification signals distort reconstructed currents and create a specific frequency. In this paper, several PWM modifying methods are examined. Moreover a method for modifying signals is proposed that prevents harmonic currents from distorting reconstructed currents and creating a low frequency. Simulated and experimental results show good performances of total harmonic distortion and a high frequency.