Switched-Capacitor-Based Neutral-Point-Clamped Quasi-Switched Boost Multilevel Inverter

Abstract

Reliable and efficient inverters are becoming essential in the current scenario of electrical power generation from renewable energy sources. Owing to inherent buck–boost ability and shoot-through immunity, the single-stage inverters are getting solid evaluation as compared to conventional inverters in the present era of renewable energy generation. However, the maximum attainable boosting of the single-stage inverters is limited by means of device stresses and spectral performance. This paper proposes a switched-capacitor-based quasi-switched boost neutral-point-clamped single-stage multilevel inverter. It is able to make desired AC output voltage in a single-stage conversion from a low-level DC voltage engendered by renewable sources such as fuel cell and PV cell. Further, it can attain high voltage gain at reduced voltage stresses on the switches, capacitors and diodes by cascading multiple switched-capacitor cells to quasi-switched boost network. The working principle and steady-state analysis of proposed topology are presented in order to obtain mathematical relation between input and output voltages. The effectiveness of the proposed inverter has been compared with other impedance-source multilevel inverters in terms of voltage gain, boosting capability, voltage stresses and efficiency. The operation of the proposed system is verified by MATLAB simulation. Also, a laboratory prototype is built and tested to verify the theoretical analysis.