Fuzzy logic controller for nine level multi-level inverter with reduced number of switches

In this paper, a Fuzzy controlled nine level inverter with reduced number of switches is designed. The Fuzzy logic controller is adaptive in nature to operate in closed loop environment without any mathematical model. The reduced number of switches combination in multi-level inverter system reduces the considerable amount of switching losses in the system. The present topology having ten switches and six diodes to generate nine levels of AC output voltage. The Phase Disposition (PD) Pulse Width Modulation (PWM) technique used for generating triggering pulses to the switches in the Inverter. the RMS voltage compared with the reference value to generate error. Mamdani type Fuzzy Logic Controller (FLC) is used for control operation according to the error value. This control topology has the provision to operate in a wide range of reference voltages (either fixed or variable). The FLC has input variable as error in voltage and output variable as amplitude of reference sine wave. The rules of the FLC will control the amplitude of the PWM sine wave with respect to the error voltage. The open loop and closed loop of proposed nine level MLIs with the reduced numbers of switches and their performance with FLC are presented.