Comparison and optimisation of three-level neutral point clamped dual output inverter

Multi-level inverter gives low total harmonic distortion when compared to the two-level inverter. A huge number of switches are required to enhance the performance of multi-level inverters. Conventional neutral point clamped (NPC) three-level inverter needs 12 switches to control a single three-phase load. In this research, dual input and output reduced switch count three-level inverter topology with a minimum number of switches is proposed to reduce the system cost, weight and driver circuits. The sinusoidal pulse width modulation (SPWM) control techniques are developed to control NPC dual inverters. The dual inverter with constant frequency and variable frequency mode are simulated by MATLAB Simulink software and the results are discussed in detail. The analysis plan with 15 different combinations of input parameters is developed as per the Box-Behnken method and the results are compared and discussed. Also, the results such as output voltage, V-THD, I-THD and efficiency are analysed by regression analysis and the derived regression equations can be used to predict the output parameters. The combination of input parameters and dual inverter topology, which give optimum output values are identified by composite desirability analysis. This dual inverter reduced switch count topology can be used for renewable energy applications to reduce the inverter cost and space.