Mitigation Methods of Voltage Disturbances and Harmonic Currents of PWM Two-Level Inverter Supplying The 6-Pulse Diode Rectifier

Abstract

Common-mode voltage Current harmonics Differential-mode voltage PWM modulation Three-phase voltage inverter Two-level PWM inverter In fast charging station for Battery Electric Vehicles (BEVs) the three-phase PWM (Pulse Width Modulation) inverters generate parasitic Differential-Mode Voltages (DMV) and Common-Mode Voltages (CMV). Parasitic voltages are a side effect of using the width modulation to shape the phase-to-phase inverter's voltage. In this article the authors present a mathematical description of the differential-mode (DM) and common-mode (CM) voltages and carry out their spectral analysis. Based on the spectral harmonics analysis, the authors present a method for filtration of harmonics of DM and CM voltages aimed at limiting the capacitance parasitic currents: due to DM voltage-phase-to-phase parasitic current and CM voltage-ground parasitic currents. A resonant filter was used to eliminate harmonics of the input rectifier of the DC/DC converter supplied from a voltage inverter. As a result of tests, the T HD i harmonic content factor was significantly reduced and ground leakage current was eliminated from the PE electric shock protection system.