Optimized Reference Points Based Vector Control of Induction Motor Drive for Electric Vehicle

Abstract

In this paper, to reduce the power consumption and to improve the efficiency in both steady state and transient condition, optimized operating point selection based control of induction motor is presented. Firstly, the steady state non-linear loss function, which incorporates iron loss and saturation is solved for steady state optimized operating point (OOP) references. To enhance the maximum torque along with reduction in energy consumption during low speed transients, over fluxing based OOP reference selection is proposed. To overcome the adverse impact of over fluxing, in the decoupled control and to make the selection process robust, model reference adaptive system (MRAS) is used for parallel estimation of rotor time constant and stator resistance. Super twisting sliding mode observer (ST-SMO) is incorporated for speed estimation, which is also utilized as reference model (rotor time constant estimation) and adjustable model (stator resistance estimation) in MRAS based observer. This OOP reference selection method is implemented along with the rotor field-oriented control (RFOC) for the induction machine. From the simulation and experimental results, it is justified that the presented algorithm reduces the power consumption and improves the efficiency at all the modes of operation of electric vehicles.