Harmonic Elimination in Three Phase Cascaded Multilevel Inverter using Genetic Algorithm

摘要

Growth of a nation depends on the optimum utilization of energy, especially electrical energy, as all the industries, directly or indirectly, need electrical source which is mostly obtain through conventional sources of energy. These sources are limited which are likely to vanish in near future. This has forced harnessing of electrical energy from non-conventional energy resources. The electrical energy obtain through these sources are direct current but most of the electrical drives need alternating current for its operation hence an alternating current at fundamental frequency and magnitude could be achieve through inverter. It acts not only as back-up for drives systems but also as standby supply at domestic levels. An inverter contains controllable power electronic devices which could be switched on and off thereby leading to generation of harmonics, especially dominant orders of harmonics have their effect in form of generating heat within the inverter and also in other power system components. Hence, they need to eliminate. One among many techniques could be Selective harmonic elimination PWM (SHE-PWM). In this paper, a multi-level Cascaded H-bridge inverter has been proposed. The optimized switching angles have been generated through Genetic Algorithm optimization tool by solving nonlinear equations. The simulated result shows that harmonics order, up to 17^th order, have been reduced in no load output voltage. This waveform could be smoothened using low pass filter and intern applied to different types of load.