Performance Analysis of Fixed and Variable Frequency Multi Shape Carrier-Seven Level Multilevel Inverter

This paper is based on the performance analysis of symmetrical seven level multi-level inverter through fixed and variable frequency multi shape carriers. The proposed circuit has been divided into two parts. (i). Level decider circuit and (ii). Inversion circuit. The level decider circuit uses 3 switches, 3 DC sources (fixed voltage) and 3 diodes, which are facilitating to bring out seven levels. The inversion circuit is an H-bridge circuit which is assisting for inversion operation. The carriersintersectionswith the reference sine wave is deciding how multilevel output closeness to the required sinusoidal wave. Triangle carrier, sine carrier and inverted sine carriers are designed with Phase Disposition (PD), Phase Opposition Disposition (POD) and Alternate Phase Opposition Disposition (APOD) configurations. The MATLAB based simulation is done with fixed frequency (1 kHz) and variable frequency (1-2 kHz) with above planned carriers and itemized configurations. The random frequency is designated by the Linear Feedback Shift Registers(LFSR)technique. The performance factors THD, WTHD, HSF and fundamental voltage are reported for the evidence.