Cascaded H-Bridge Multilevel Inverter Using Multi Winding Transformer and Single DC Input with Single Carrier Sinusoidal PWM Control

This paper proposes single carrier sinusoidal PWM based cascaded H-bridge multilevel inverter which employs single dc input power source with isolated unequal turns ratio low-frequency power transformers. Generally cascaded H-Bridge inverters are used to generate levels under trinary fashion switching scheme, where, n represents the number of H-Bridges used. In this topology three H-Bridges are used and hence 27 levels are achieved with single DC input and multi winding transformer unit. Hence harmonics are reduced in the output level. Therefore, an economical and efficient inverter can be designed. In this proposed topology trinary switching pattern is used to achieve the desired levels. Single carrier sinusoidal modulation (SC-SPWM) technique is used which provides variable voltage and a variable frequency supply. The effectiveness of the system is verified through simulation using MATLAB/Simulink.