Three-phase seven-level SFO PWM inverter with high gain voltage multiplier for hybrid distributed energy systems

Abstract

ABSTRACT– In this paper, seven-level cascaded asymmetrical H bridge inverter of reduced DC source with reduced switches is developed. Effort has been made to involve the renewable energy sources such as PV and the PEM fuel cell to take part in the energy harnessing process. A high gain P/O SL Luo Relift circuit is incorporated to boost and stabilise the distributed energy source voltages which produce a dual DC link for the developed modified inverter. The enhancement of fundamental voltage at lower modulation indices is realised using the modulation strategy of switching frequency optimal pulse width modulation of variable frequency which enables balanced switching actions, reduced switching losses and minimal THD for the developed inverter. Simulation model developed using Matlab/Simulink is presented to validate the performance of high gain P/O SL Luo Relift three-phase asymmetrical cascaded H-bridge seven-level inverter and to indicate the effectiveness of the proposed modulation strategy for the inverter. The obtained FFT spectral analysis for the three-phase multi-level inverter output voltage is well below the IEEE harmonic limits.