A life tester for hybrid vehicle e-machine systems

A life tester system for evaluating and validating the electric machine system used in hybrid electric vehicles (HEV) is presented. This tester is intended to simulate a dynamometer unit. Two traction machines in the life tester are installed in back-to-back configuration coupled on the same shaft. One machine runs in closed-loop speed control and the other accordingly run in a torque mode. The speed-mode e-machine system will automatically balance its torque output with the other machine torque. In such a configuration, the tester system power consumption can be minimized (one in generation mode, the other in motoring). Two e-machine systems can be simultaneously tested under various load and environment cycle conditions for life endurance test. The control strategy of the life test system is discussed.