MTPA Associated DTC Methodologies for Enhanced Performance and Energy Savings in Electric Vehicle Mobility With Induction Motor Drive
Pratibha Naganathan, S. Srinivas
Abstract
This article presents two new energy-saving control methodologies for induction motor (IM)-based electric vehicles (EVs) that exploit advantages from both direct torque control (DTC) and maximum torque per ampere (MTPA) control. While the first variant implements IM control through hysteresis controllers, the second variant employs a modulator to achieve constant switching frequency. For both variants, a flux observer is carefully designed to minimize the effects of IM parameter variations. Detailed torque ripple and power loss characteristics of IM drive controlled with the envisaged MTPA-DTC variants are also presented. The proposed techniques clearly show a reduction in current drawn by the EV system in comparison with the existing techniques. The IM drive is tested for fast acceleration and also the European Union (EU) Urban Drive Cycle to assess the advantages offered by the proposed control techniques. Advantages obtained, such as simple and fast implementation, high dynamic performance, reduced stator current, power loss leading to improved IM efficiency, and reduced steady-state torque ripple followed by energy savings obtained in the EV, are presented in the article, which can greatly benefit EV applications.