Power Quality Enhancement of Five-Level Converter Using Floating H-Bridges of Voltage Ratio 4:1/2:1/4

This work presents a way to improve the power quality of a three-phase five-level converter by cascading it with two floating H-bridges of voltage ratio 4:1/2:1/4. The proposed configuration enhances the power quality by producing a seventeen-level output voltage waveform and thirty-three levels in line voltage waveform. In this paper, the operation of the proposed converter is explained including various switching states and capacitor voltage balancing scheme. The performance of the proposed converter is assessed in simulation studies carried out in MATLAB/Simulink environment. The evaluation involves the use of a multi-carrier level-shifted PWM technique and a two-level hysteresis controller for voltage balancing of the capacitors.