A soft switching scheme for a PWM inverter using a fuzzy logic controller

This paper presents a fuzzy logic controller for a soft switched PWM inverter. Soft switching of the inverter switches is achieved by the aid of a front end DC voltage notching circuit consisting of resonant components and auxiliary switches. The proposed fuzzy logic controller controls the operation of the auxiliary switches such that the DC bus voltage is brought to zero whenever an inverter switch needs to change states thereby allowing soft switching. The proposed controller is capable of providing more robust control as compared to the existing methods. The design aspects of the proposed controller involving fuzzification, control rule based establishment and defuzzification is presented. Simulation results which demonstrate the feasibility of the fuzzy controller are included.