COMPARATIVE ANALYSIS OF THE PULSE WIDTH MODULATION METHODS FOR THE PROPULSION FREQUENCY CONVERTER

In this paper, using a simulation model developed in Simulink, the three most common Pulse Width Modulation techniques are analyzed: hysteresis current control method, sine-triangle method, and space vector modulation method. Simulation is performed in the time domain and a quasi-stationary approach is applied for the simulation results analysis. Waveforms and harmonic distortion of propulsion motor's stator voltage and current are analyzed at different speeds and appropriate loads for all three modulation methods. The obtained results indicate that, at approximately equal switching frequencies, the total harmonic distortions of propulsion motor voltage and current are arguably lowest when the space vector modulation method is used and are highest with the hysteresis current control method. Frequency modulation index has a relative small impact on THDu and a very large impact on THDi.