Current Control for Multi-Level Inverters Based on Fuzzy Logic Sliding Mode Control Approach

This paper presents a new method of current control for the cascaded three-level inverter based on fuzzy logic sliding mode control (FLSMC). To minimize the chattering caused by fast and large amplitude changes of currents and voltages across the load, a fuzzy logic observer is utilized to identify the switch control law. The proposed FLSMC method shows that the measured current can closely follow the set current, and the high harmonic components of the output voltage are low. Additionally, during the operation of the multilevel inverter system, the common-mode voltage (CMV) is also reduced. The proposed method can reduce the number of switching times, which results in lower losses due to the switching process of the components. The proposed FLSMC is based on a control algorithm, not relying on carrier waves to generate PWM pulses, unlike the conventional inverters of the past. Instead, it generates PWM pulses by comparing the control signal with voltage levels. The simulation and testing results have demonstrated the superiority and high efficiency of the proposed FLSMC method.