Reducing the output harmonics of cascaded H-bridge multilevel inverter for Electric Vehicle applications

Both Hybrid Electric Vehicles (HEVs) and Electric Vehicles (EVs) need a traction motor and a power inverter to drive the vehicle motor. The requirements for the power inverter include high peak power, low output harmonics, inexpensive circuit and low continuous power rating. In this paper, reducing the output harmonics of cascade H-bridge multilevel inverter for electric vehicle applications is proposed. Switching angles of switch devices are determined by selective harmonic elimination technique. So, the effect of low order harmonics are reduced, as a result the efficiency of system has improved. Moreover, the number of DC voltage sources that used in the proposed inverter is less than conventional multilevel inverters that leads to reduce the inverter costs. A fundamental frequency switching methods has been used for modulation of inverter and to produce a seven-level phase voltages. Simulation results on various conditions were carried out using PSCAD/EMTDC software.