Computer-Controlled Electric Drive Train Test Facility 820262
This paper describes the design and operation of a computer controlled road load simulator for the development of electric vehicle drive trains. Past experience has shown that it is difficult for a driver to execute a driving schedule exactly, cycle after cycle, day after day. Prevailing atmospheric conditions affect battery capacity, vehicle drag, and even motor efficiency. It is not reasonable to make judgments about vehicle range when day-to-day variability in testing conditions can cause range performance differences on the same order of magnitude as those noted between different drive systems. These were the reasons for development of the road load simulator.
The system consists of a DC dynamometer, digital mini-computer, torque and speed transducers, and any electric vehicle drive train. Complete power trains consisting of batteries, motor, choke, controller and chopper can be tested under controlled and repeatable test conditions for simulated vehicles. This can be done not only at steady speeds, but under actual driving cycles (such as EPA Urban or SAE J227a) with the computer acting as the driver.