Design, Commissioning and Testing of an Electrodynamometer Based on PM Synchronous Machines

AbstractThis paper addresses the design, simulation, commissioning and testing of an electrodynamometer (ED) to assess the dynamic performance of Electric Vehicles (EV). The EV-ED system is comprised of two electric machines coupled mechanically. The traction machine is a 7.75 kW Permanent Magnet Synchronous Motor which is controlled by means of a vector control and it is coupled mechanically to a similar machine which is used as a mechanical load. The load machine was fed by two DC/AC converters connected by the DC bus allowing bidirectional power flow. The electrodynamometer was controlled by means of a National Instruments electronic board and Labview software. Several load profiles and inertias were programmed to emulate an Electric Vehicle (EV). The traction machine 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 control of the traction machine was validated for different driving cycles. Matlab/Simulink simulations of the machine control and electrodynamometer along with experimental results illustrating the response of the machine control under the characteristic load profile of an EV are presented and analyzed. Traction and regenerative breaking stages are analyzed and discussed broadly