Dual carrier modulation technique using MATLAB for a five level inverter

Multilevel inverter have become an effective and practical solution for increasing power and reducing harmonics of AC waveforms. This paper mainly focuses about a single phase five level inverter using a novel dual carrier modulation technique which is simulated using MATLAB. The inverter consist of a full bridge inverter and an auxiliary circuit with four diodes and a switch. The inverter produces output voltage in five levels zero: +0.5Vdc, +Vdc, -0.5Vdc and -Vdc. The dual carrier modulation technique uses two identical triangular carrier signals each with amplitude exactly half of the amplitude of the sinusoidal reference signal to generate PWM signals. The performance evaluation of the proposed PWM strategy for single phase five level inverter is done using MATLAB Simulink. Total harmonic distortion and switching losses for both the dual reference modulation and dual carrier modulation techniques are compared. It is observed that the dual carrier modulation technique gives reduced total harmonic reduction and switching losses.