Content area
Full Text
Received: November 2017 Revised: January 2018 Accepted: February 2018
ABSTRACT:
The conventional two-level inverter fed induction motor drive causes pulsating torque because of harmonics present in the inverter output voltage. Therefore, minimization of harmonics content is the major challenge in two-level inverter supplied drives. In this paper, a harmonic reduction technique for multiple pole-pair induction motor drive is presented. A modified carrier based space vector PWM technique is used with suitable phase shiftbetween different (modulating and carrier) signals to cancel the harmonic content. In order to use this PWM technique, each pole-pair winding coil of a four-pole induction motor is supplied with two-level inverters separately as dual inverter fed drives. Two dc voltage sources are used to feed all these two-level inverters and by connecting in proper sequence zero sequence currents can be eliminated. By using proposed PWM technique to the inverter configuration, all harmonics will appear at four times of the switching frequency. The proposed inverter concept is tested with 5hp four-pole induction motor in MATLAB/Simulink and experimentally also verified with laboratory prototype. Simulation and experimental results demonstrate the performance of the proposed inverter topology and also show the improvement in harmonic profile.
KEYWORDS: Carrier based SV PWM Technique, Induction Motor, Multi-level Inverters.
(ProQuest: ... denotes formulae omitted.)
1. INTRODUCTION
In recent years, requirement for the inverter fed ac drives is growing considerably because of the advances in power electronics. Mostly two-level inverter configurations are used for speed control of the AC motor drives. But the two-level inverter output voltage consists of more harmonics along with necessary fundamental voltage component [1-2]. The harmonics present in the two-level inverter output voltage will causes torque ripple and current ripple and it will cause the damage (reduce the life time) of stator winding and power electronic switches [3-4]. Hence the minimization of harmonics is the important issue in two-level inverter supplied ac drives. The harmonic elimination concepts presented in paper [5-7] will minimize the effect of harmonics on the load by transferring all harmonics to switching frequency. But, the harmonics near switching frequency will also cause problem to the stator winding of the motor and to power electronic devices. To minimize this effect of harmonics present at switching frequency, the carrier signal frequency has to be...