PERFORMANCE EVALUATION OF AN ENERGY EFFICIENT DRIVE FOR ELECTRIC VEHICLES

Abstract

of petroleum products, it is high time to switch over from less-efficient, carbon emitting Internal Combustion (IC) engines to highly efficient, eco-friendly (at the point of use) Electric Vehicles (EV). The serious limitations for commercialization of this vehicle technology are bulky batteries and ineffective control techniques. With recent advances in power electronics and material science efficient converters and motor could be designed respectively. Induction motors and Permanent Magnet motors can be employed because of high efficiency and compactness. But speed control is complex. By employing Vector Control, Fuzzy and Artificialb Neural Network based control techniques, high dynamic response is obtained. Computational intensive problem associated with above control techniques can be addressed with modern DSP and microprocessor technology. Research is still going on the high energy density batteries though Nickel-Metal-Hydride and Lithium ion batteries are promising. In addition, Fuel cells and Ultracapacitor technology is under research. Vector Control technique, also known as Field-Oriented Control (FOC), allows a squirrel-cage induction motor to be driven with high dynamic performance that is comparable to a DC motor. This decouples the stator current into two components: one providing the air-gap flux and other producing torque. It provides independent control of flux and torque by ensuring correct orientation of voltage and current space vectors and generate control input signals. Thus, with vector control, an induction motor can operate as a separately excited DC motor. In this work, a comprehensive mathematical modeling of Vector Controlled Induction Motor Drive (VCIMD) and Vector Controlled Permanent Magnet Synchronous Motor Drive (VCPMSMD) has been carried out to investigate the performance of drive system. The dynamic response of the VCIMD andVCPMSMD under various operating conditions such as starting and load perturbation subjected to modeled road load conditions, is simulated and examined in MATLAB 7.6.0 environment using simulink and Power System toolboxes. Further efficiency of these drives is optimized. The PI speed controller is used. PWM cascaded H-bridge inverter is amP used since separate DC sources are available in an EV. Also efficiency optimization is done for the induction motor and the results are compared with the PMSM