Fast Fourier Transform Analysis on Harmonic Content for SPWM Design and Implementation Based on New Modulation Approach

摘要

This paper is focusing on optimizing harmonic content in Sinusoidal Pulse Width Modulation (SPWM) design. The results show that by varying number of bits, modulation index and switching frequency, the harmonic content to Total Harmonic Distortion (THD) can be analyzed and optimal method to reduce the harmonic content of THD can be found. This SPWM is designed using VHDL and implemented on ALTERA (DE2-70 board). The results, the SPWM signals and its Fast Fourier Transform (FFT) waveform, are measured using Digital Oscilloscope. The Total Harmonic Distortion (THD) is calculated from measured waveform. From the analysis, for 10 bit, mod index one and at frequency of 20 kHz, Total Harmonic Distortion for the SPWM design is optimized.