Harmonic Wave Analysis and Suppression Research on Three-phase SPWM Inverter

摘要

The output voltage of the Sinusoidal Pulse Width Modulation (SPWM) inverter contains various ultra harmonics. It increases the system's power consumption and generates the harmonic interference. By establishing the mathematical model of the three-phase inverter and doing the FFT transformation on the output voltage, it analyses the relation between the output voltage and the combined conduction states of the inverter's switches during one waveform cycle, it also analyzes the main parameters, modulation ratio of the voltage and carrier signal which can affect the inverter's harmonic content. Simulation verifies the distribution regularities of each harmonic of SPWM inverter's output voltage. It indicates that SPWM modulation method can make the output harmonics high frequency, the harmonic characteristic and modulation depth are closely related to the carrier frequency. This study has great significance on the rational selection of modulation depth and carrier frequency, improvement of the inverter's efficiency and reduction of harmonic distortion.