Experimental electrodynamometer to emulate the dynamic performance of an electric vehicle

Abstract

This paper addresses the design, simulation and experimental validation of an electrodynamometer (ED) to assess the dynamic performance of an Electric Vehicle (EV). The EV-ED system is comprised of two electric machines coupled mechanically. The traction motor is a 10 hp Permanent Magnet Synchronous Motor (PMSM); it is controlled by means of a vector control. The motor is mechanically coupled to a similar motor which is used as a load machine. An electrodynamometer was implemented by using the load machine which was fed by two DC/AC converters connected by the DC bus allowing bidirectional power flow. The electrodynamometer is controlled by means of National Instruments electronic board and LabView software. Several load profiles and inertias were programmed to emulate an Electric Vehicle (EV). The motor drive was implemented with a PP75T120 Powerex Inverter. PWM generation and control strategy were implemented on a MC56F8357 Freescale Digital Signal Controller (DSC). The speed motor-control was validated for different driving cycles. Matlab/Simulink simulations of the motor control and electrodynamometer along with experimental results illustrating the response of the motor control under the characteristic load profile of an EV are presented and analyzed. Acceleration and regenerative break stages are discussed broadly.