SEVEN LEVEL CASCADED MULTILEVEL INVERTER FOR POWER QUALITY IMPROVEMENT IN INDUCTION MOTOR

Induction motors are the workhorses of any industry. The speed control of induction motor is mainly done through Variable Frequency Drives (VFD). The VFD includes IGBT or MOSFET based voltage source inverter which is fed from a rectifier. The output AC of the inverter contains more harmonic content and has square waveform. However sinusoidal PWM technique is used to get much more sinusoidal output AC. But the frequent switching of the switches will result in increasing the harmonic content which in turn increases the size of the output filter. To overcome this, a cascaded multilevel inverter is proposed to reduce the harmonic content and improve the power quality. The cascaded multilevel inverter produces nearly sinusoidal output compared to sinusoidal PWM switching. The common configuration of cascaded multilevel inverter includes separate DC sources for each H-bridge. The proposed 3 phase cascaded multilevel inverter has only one DC source. By choosing the adequate switching angles and appropriate carrier frequency, harmonics can be eliminated in the output waveform. Appropriate choice of a fundamental frequency switching pattern can produce a nearly sinusoidal output thereby improving the power quality. In this work, the aim to study the performance of an induction motor, which is used as a medium. Citation: Sakthivel C, JCT College of Engineering and Technology, Coimbatore, Tamil Nadu; E.Parimalasundram ,Sree Vidyanikethan Engineering College, Tirupati, Andhra Pradesh; V.Kumaresan ,JCT College of Engineering and Technology, Coimbatore, Tamil Nadu; P.Samjasper ,JCT College of Engineering and Technology, Coimbatore, Tamil Nadu; J.Madheswari ,JCT College of Engineering and Technology, Coimbatore, Tamil Nadu. "SEVEN LEVEL CASCADED MULTILEVEL INVERTER FOR POWER QUALITY IMPROVEMENT IN INDUCTION MOTOR." Global Research and Development Journal For Engineering : 258 - 264.