Harmonics Minimization in Wide Modulation Range Using Improved Differential Evolution Optimization Technique and Hardware Validation

In order to minimise the switching losses, low switching frequency pulse width modulation (LSPWM) approach is chosen for medium voltage high power applications. In these techniques, solving a system of non linear transcendental equations is the primary issue to obtain the switching instants to minimize the pre-specified harmonics along with control on the fundamental component. The number of switching angles employed is proportional to the amount of harmonics minimized from the output. Furthermore, the system of equations exhibits multiple solution, no solution or unique solution in different range of modulation index. In this paper, harmonics minimization based on differential evolution in voltage source inverter is proposed to determine the optimum solution in complete linear range of modulation index to minimize lower order harmonics from the output voltage. To validate the proposed concept, a TMS320F2812 DSP based hardware implementation of voltage source inverter developed with intelligent power module (IPM), FSB20CH60B/600V @ 20A is given in the paper.