A novel dynamometer system for testing high power variable frequency drives

In this paper is proposed a novel dynamometer system for testing high power variable frequency drives (VFD). This system, which is built and fully functional, has no movable parts. It is comprised of a 1.7MW active front end drive, a reconfigurable system of inductors and the drive under test. Main advantages of this dynamometer system are flexibility, high efficiency, low maintenance, small footprint and environmental friendly. The flexibility of the system allows for testing drives at different power, voltage and frequency levels. Since the power is circulated within the system, the power loss is minimal and the energy savings and environmental benefits are considerable, especially when testing high power drives. By using a motor-less system the audible noise levels are reduced and the maintenance work virtually eliminated. The system is remotely controlled from a computer controlled interface through Profibus. Results presented in this paper show that the dynamometer system not only performs very well in testing the drives under their full power capability, but also does not interfere with the normal operation of the factory equipment fed from the same distribution transformer.