A Modular Hybrid Cascaded Multilevel Converter For Efficient Power Conversion Using Sinusoidal Pwm Techniques

Abstract

Multilevel Converters are one form of voltage source converters emerging as a new form of power converters for high power and medium power applications. Multilevel voltage source converters are typically used to synthesize the output voltage to staircase shaped sinusoidal voltage wave forms. The work contained in this paper involves a multilevel converter called as hybrid cascaded multilevel converter which is supplied from several dc voltage sources. A simulation of a three phase, eleven level hybrid cascaded multilevel converter using a modular structure called as Hybrid cascaded multilevel converter was done. This arrangement consists of a hybrid combination of cascaded half bridge converters and a single H-bridge. The input to each cascaded half bridge is supplied from individual battery source. All cascaded half bridges produce a staircase shape half sinusoidal output voltage. A single H-bridge alternates the direction of dc to ac. The output voltage control is obtained by suitable modulating strategies based on carrier cascaded sinusoidal pulse width modulation. The circuit has the advantage of less number of switches consequently leading to reduced switching and conduction losses and complexity of the circuit is thereby reduced due to less number of components. These multilevel inverters finds their applications in Electric and Hybrid electric vehicles, adjustable speed drives, photovoltaic applications, Wind energy applications and utility systems containing HVDC and active filters.