Novel Asymmetrical Pulse Width Modulation Method

The paper proposes new asymmetrical PWM that can be used for operation of multilevel inverters. The working and construction principle of this PWM is demonstrated on 13-level PWM signal that is applied to nine-level inverter and operates it as 13-level inverter. The proposed PWM signal consists of 5-level hybrid PWM which is constructed from two PWM signals-combined parts of the standard 5-level Phase Disposition (PD) PWM and pulsed PWM. The sum of these two PWM signals produces the desired 13-level PWM signal that is applied to the 9-level cascaded inverter. The proposed PWM method allows reduction of 13-level inverter components compared to the standard topologies such as neutral point clamped or flying capacitor inverters. This results in smaller size, weight and cists of the inverter. Extensive simulation results validate the practicability of the proposed PWM method. The proposed method can be extended to any desired number of levels.