A new Hybrid Cascaded H-Bridge Multilevel inverter - Performance analysis

Cascaded H-Bridge multilevel inverters synthesize a medium voltage output based on a series connection of power cells which use standard low-voltage component configurations. This characteristic allows one to achieve high-quality output voltages and input currents and also outstanding availability due to their intrinsic component redundancy. Due to these features, the cascaded multilevel inverter has been recognized as an important alternative in the medium-voltage inverter market. This paper presents a cascaded H-bridge multilevel boost inverter for electric vehicle (EV) and hybrid EV (HEV) applications implemented without the use of inductors. Traditionally, each H-bridge needs a dc power supply. The proposed design uses a standard three-leg inverter (one leg for each phase) and an H-bridge in series with each inverter leg which uses a capacitor as the dc power source. The Hybrid Cascaded H-Bridge Multilevel inverter is implemented using the Selective Harmonic Elimination PWM (SHEPWM) technique. The proposed topology offers an intuitive method for minimizing the total harmonic distortion (THD) of the output voltage of the inverter which has been verified using the MATLAB simulation. A fundamental switching scheme is used to do modulation control and to produce a five-level phase voltage.