Research on a novel AC variable-frequency dynamic power dynamometer

Traditional dynamometers, such as hysteretic dynamometers, eddy current dynamometers, mechanic dynamometers and waterpower dynamometers, may consume lots of fuels and electrical energy while working, which causes the energy waste. Also, these dynamometers should be equipped with additional radiators to keep the dynamometers cool. A type of novel dynamic power dynamometer scheme is presented based on PWM rectifier and direct torque control (DTC) technology for induction motor in this paper. The proposed dynamometer can operate in both motoring and generating states by DTC of induction motor, which ensures the swift torque response of the dynamometers. Three-phase PWM technology enables the bidirectional flow of the energy. PWM rectifier can not only provide DC link voltage for the induction motor, but also feed back the energy generated by the dynamometer to AC mains, which guarantees both current sinusoid and unit power factor. This scheme decreases the harmonic disturbance to the AC mains, saves the energy sources, and cut the cost of purchasing radiator. In order to validate the feasibility of the scheme, an experimental device based on the DSP and intelligent power module IPM is designed. Experimental results indicate that the novel dynamometer has an outstanding dynamic and static performance.