A New Approach for Transistor-Clamped H-Bridge Multilevel Inverter with voltage Boosting Capacity

Abstract

Multilevel converters offer high power capability, resulting with lower output harmonics and lower commutation losses. Their main disadvantage is their complexity, requiring a great number of power devices and passive components, and a rather complex control circuitry. This paper presents a new topology of the multilevel inverter with feature like output voltage boosting capability along with capacitor voltage balancing .The proposed multilevel inverter uses conventional transistor clamped H-bridge (TCHB) with an bidirectional switch and four auxillary switches producing a boost output voltage . The single unit of new topology produces five-level output with output voltage double the input DC voltage where as a single unit of conventional H-bridge produces three-level ouput voltage similar to input DC voltage. A novel universal control scheme is used which results in balanced distribution of power among H-bridge cells. This control scheme can also be used for the charge balance control with multiple input DC sources in any given topology. The analysis of the output voltage harmonics is carried out and compared with previous topology and the conventional cascaded H-bridge inverter topology. The proposed multilevel inverter topology is modelled using matlab/simulink. From the results the proposed inverter provides more output voltage.