Enhanced frequency shift carrier modulation for H-bridge multilevel converter to conquer the impact of instability in deputize condenser voltage

Abstract

H-bridge multilevel converter is the most challenging topology from nominal to high power applications. However, when the energy is exchanged between AC side and DC side or vice versa, the fluctuation in the capacitor used in deputize unit is unavoidable. The fluctuation in the deputize unit is due to the increase in the total harmonic distortion by the capacitor in the output voltages. This total harmonic distortion is evaded by exploring the deputize unit capacitor voltage mathematically. This paper proposes the enhanced frequency shift carrier modulation in H-bridge multilevel converter to suppress the influence of fluctuation in deputize unit capacitor voltages. Enhanced frequency shift carrier modulation is considered for nonlinear compensation. The principal results of using this enhanced frequency shift carrier modulation improvise the total harmonic distortion in the output voltage of H-bridge multilevel converter. Simulation and experimental results are done using MATLAB/SIMULINK to verify the effectiveness of the proposed control scheme.