Research on DC Voltage Utilization Ratio of Inverter SHEPWM Control Method Based on Immune Algorithm

Abstract

In the frequency conversion device, the DC voltage utilization rate is one of the important indicators to measure the advantages and disadvantages of the modulation method, and also determines the output capability of the inverter. In the three-phase bridge inverter, the DC voltage utilization rate of the conventional SPWM control method is only 0.866, and the DC voltage utilization ratio of the relatively superior SVPWM control method can reach 1. In this thesis, a three-phase bridge inverter is taken as the research object. Based on the immune algorithm, the affinity evaluation operator and the incentive calculation operator are designed for the mathematical model of the three-phase bridge inverter. Under the condition, the SHEPWM nonlinear transcendental equations are solved, and a reasonable switching angle is calculated, and then the simulation experiment is carried out. The simulation results show that the SHEPWM control method has the characteristics of high DC voltage utilization and small voltage and current harmonic content compared with SPWM control method and SVPWM control method. On the other hand, according to the simulation data, the maximum value of the DC voltage utilization of the SHEPWM control method can be obtained between 1.022 and 1.031.