Harmonic Reduction of Cascaded H-Bridge Multilevel Inverter Using Advanced Level Shifted Pulse Width Modulation Technique

To convert dc power into ac power from different renewable energy resources, a multilevel inverter plays a very significant role. In order to enhance the efficacy of a multilevel inverter, several types of techniques can be experimented to the existing multilevel inverter. Due to the modulation algorithm, modulation frequency, voltage drops across the switches, and modulation of the dc bus voltage, the output voltage of the power inverter show total harmonic distortion which results in overheating of devices and reduces the life-time of devices. In this paper, a level-shifted pulse width modulation technique is proposed with a view to ameliorate the output voltage quality and reduce total harmonic distortion. This new control scheme is applied to an eleven-level conventional cascaded H-bridge multilevel inverter and compared with a conventional level-shifted pulse width modulation (LSPWM) with Phase Opposition Disposition (LSPWM-POD) technique. The performance of the proposed LSPWM has been simulated for the verification and found two optimal points in this the proposed technique provides better results.