Improved power quality converter for direct torque control-based induction motor drives

This study presents the performance of a direct torque control (DTC)-based induction motor drive (IMD) with improved power quality converter at the front end. It is designed, modelled, simulated in MATLAB/simulink platform and implemented in hardware using a digital signal processor (DSP). An improved power quality converter known as Vienna rectifier is used in the system to mitigate the power quality problems at the utility interface in the DTC-IMD. The proposed Vienna rectifier is a three switch converter to improve the power quality in terms of reduced total harmonic distortion of ac mains current, power factor correction and dc-link voltage regulation. The performance of the proposed system is validated experimentally using a DSP. The performance of the system is tested for step change in input reference speed and the load torque and it is found that the power quality indices conform to IEEE-519 standard under all operating conditions.