A high-performance ac electric drive system, consisting of a high efficiency (95 to 97%) 70-hp interior permanent magnet (IPM) synchronous motor, an advanced MOS-Controlled Thyristor (MCT)-based three-phase inverter, and microcomputer based inverterlmotor controller has been developed. This electric drive system, a joint development of Ford Motor Company and GE, was funded as a major element of the US Department of Energy's “Electric and Hybrid Vehicle Program”, contract number DE-AC08-85NV10418, and represents the state-of-the-art in electric vehicle technology.
Performance and system efficiency test results of the 3-phase MCT inverter and IPM motor (mounted in the test transaxle and coupled to the dynamometer), are presented. MCT module tests were run at 204-V, 250-V, and 270-V dc link voltages, while drive system tests were run over the torque-speed plane to characterize the electric drive system for 150-V and 200-V dc link voltages. Test results, included in this paper, show the ETX-II MCT inverter-based electric drive system has 2-3 percentage points higher efficiency than the corresponding ETX-II Darlington inverter-based electric drive, over a significant portion of the torque-speed plane.