An Improved Method for Reliability Calculation of Multilevel Inverters

In this paper an optimized structure of a five-level grid connected inverter using a lower number of switches as compared to the similar topologies is proposed. Also, reliability calculations based on the IEC-TR-6280, covering all of the multilevel components especially IGBTs and MOSFETs, are done in this paper for the suggested converter. The important points regarding this standard using in this paper is that the standard considers the performance of the system and package effects not considered in the previous papers. Considering these calculation results show that the reliability of the proposed converter is higher than the similar structures. Apart from that, FFT analysis of the suggested inverter illustrates the Total Harmonic Distortion (THD) of this inverter is considerably improved. Regarding this, to prove what were mentioned as the achievements of this paper, a Simulation results carried out by Matlab verifying the high efficiency, high reliability, low distortion of the proposed five-level inverter.