In this paper a new topology is proposed for energy storage and the power distribution using Ultracapacitors in cascaded multilevel inverters. This consists of hybrid cascaded multilevel inverter (HCMI) topologies and corresponding control strategies are applied to motor drive, interfacing both dc sources and capacitor energy storage elements. For high power motor drive application this proposed topology has a capability to produce high voltage at fundamental switching frequency makes it possible to use switches with low voltage and current ratings. The major advantages of this proposed control method are reduced switching loss, improved efficiency with less number of dc sources, elimination of harmonics and the ability of the capacitor voltage to be successfully maintained at the desired value when the machine is in transient state. In this paper a 7-level cascaded multilevel inverter with motor drive is considered. Finally, the simulation results validate the concept of this topology.

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Multilevel inverters are widely used because of its increased power rating with reduced harmonics and electromagnetic interference. The proposed 7-level cascaded H-Bridge inverter is symmetrical in nature and uses equal sources of DC voltage. Whereas 31-level cascaded H-Bridge inverter is asymmetrical in nature and uses unequal sources of DC voltage. The PD-PWM modulation technique was used here to achieve switching sequence. The proposed idea was validated through simulation and the results provide better efficiency, fewer low order harmonics and lower switching losses. The proposed topology is simulated using MATLAB / SIMULINK.