An Improved Hybrid PSO-TS Algorithm for Solving Nonlinear Equations of SHEPWM in Multilevel Inverters

Selective Harmonic Elimination Pulse Width Modulation (SHEWM) can eliminate selected low order harmonics by solving nonlinear transcendental equations to obtain the switching angles in advance and achieve precise harmonics control. However, when solving nonlinear equations, the convergence rate and solution accuracy of the existing intelligent algorithms for multilevel inverter SHEPWM will decrease with the increase of the number of switching angles. In this paper, an improved hybrid PSO-TS algorithm (IPSO-TS) is proposed for switching angle selection in PWM inverter. In the proposed IPSO-TS algorithm, both the PSO algorithm and TS algorithm are improved respectively to enhance their convergence when calculating multiple switching angles. Also, these two improved algorithms are combined to obtain the hybrid algorithm IPSO-TS, in which PSO is used to provide global search capabilities, and TS is used to increases the accuracy of solutions. Simulations are carried out using MATLAB/SIMULINK environment to demonstrate the better convergence of the proposed algorithm compared with the other existing methods. Moreover, the simulation results are further verified by experimental results.