ABSTRACT

This paper proposes the use of a nature-inspired algorithm known as Grasshopper Optimisation Algorithm for optimising switching angles applied to a three-phase 7-level cascaded H-bridge multilevel inverter. Switching angles obtained using the algorithm can be used to synthesise an optimised output voltage waveform with desired fundamental component and minimised 5th and 7th order harmonics. Simulation results show that the algorithm is able to provide switching angles over a wider modulation index range than Newton Raphson technique and is capable of minimising the objective function better than Genetic Algorithm. MATLAB/Simulink-PSIM dynamic co-simulation performed on a three-phase 7-level cascaded H-bridge multilevel inverter operated using GOA derived switching angles is able to respond to varying modulation index demand and produce the output voltage waveform with the desired fundamental component and minimised selected 5th and 7th order harmonics. Both simulation and experimental results obtained from the three-phase 7-level cascaded H-bridge multilevel inverter show good agreement, confirming the validity of the switching angles obtained using the Grasshopper Optimisation Algorithm.

摘要

本文提出使用一种名为 Grasshopper 优化算法的自然启发算法来优化应用于三相 7 级级联 H 桥多电平逆变器的开关角度。使用该算法获得的开关角度可用于合成具有所需基波分量和最小化 5 次和 7 次谐波的优化输出电压波形。仿真结果表明，该算法能够在比牛顿拉夫森技术更宽的调制指数范围内提供切换角度，并且能够比遗传算法更好地最小化目标函数。MATLAB/Simulink-PSIM 动态联合仿真在使用 GOA 导出的开关角运行的三相 7 级级联 H 桥多电平逆变器上执行，能够响应变化的调制指数需求并产生具有所需基波分量的输出电压波形并最小化选定的 5 次和 7 次谐波。从三相 7 级级联 H 桥多电平逆变器获得的仿真和实验结果均显示出良好的一致性，证实了使用 Grasshopper 优化算法获得的开关角度的有效性。