TLBO based Selection of Optimal Switching angles in SHE Control of CMLI with Unequal DC sources

摘要

Cascade H-bridge multilevel inverters topology has drawn significant importance by producing good quality output voltage waveforms, less dv/dt stress, simple in topology and more suitable to interface DC solar panels than other multilevel inverter topologies. Generally, it is assumed that DC solar panels will produce same magnitude of DC output voltage but practically it may produce sight variations in the DC output voltages. Providing the optimum switching angles in control of CMLI with DC sources which has sight variations in the output voltage is a challenging task. In this paper, the nonlinear SHE equations set which are formulated in control of three phase CMLI with unequal DC sources are solved by TLBO algorithm to obtain optimum switching angles to minimize %THD. To validate the proposed approach, developed algorithm is run at different values of M_I and obtained values of %THDs satisfies IEEE 519-1992 harmonic guidelines.