A high performance dynamometer for drive systems testing

A dynamic dynamometer and its attendant man-machine interface, designed to facilitate the development and testing of adjustable speed drive systems, is presented in this work. It is based on a vector-controlled induction motor drive supplied from the AC mains through a double PWM converter that provides desirable features such as bi-directional power flow, near unity power factor and low harmonic factor at the AC mains. The proposed system estimates torque from machine terminal voltages and currents, thus eliminating the load cell and special mechanical construction, and allowing a standard induction machine to be employed, with conventional machine coupling. Several commonly used load torque profiles, both static and dynamic, can be emulated by the dynamometer. A theoretical analysis is first presented, followed by a detailed simulation study to assess the torque estimation sensitivity to parameter variation as well as the overall system performance under dynamic conditions.