Genetic algorithm optimization of SHE-PWM technique for paralleled two-module VSIs employed in electric drive systems

Voltage source inverters (VSIs) can be functioned in parallel with the aim of using limited power rating switching devices in high power electric drive systems. However, appropriate modulation strategies should be selected to provide the desired output voltage waveform at low switching frequency. Selective harmonic elimination (SHE) is one of the most adopted pulse width modulation (PWM) strategies that eliminate low-order harmonics from the output voltage. This paper proposes a genetic algorithm (GA) based SHE-PWM strategy for two VSIs operated in parallel and applied for electric drive system. The proposed modulation technique can eliminate extra harmonic contents from the output voltage by using different switching forms simultaneously. The optimum firing angles of each VSI is determined by solving a multi-objective optimization problem using GA. The various functions and configuration parameters that are required for solving the optimization problem are presented and described. Simulation results using different firing angles are presented to verify and validate the advantages of the proposed modulation strategy.