Dynamics of different speed controls of ultra high speed induction generator using approximate and accurate model

The paper is concerned with the study of ultrahigh speed induction machine (USIM) applied in the utilization of renewables and recovering waste energy. The rated speed of the machine is 90 000 rpm. The main target of the study is to investigate the performance of the speed control loop in order to avoid or minimize the overspeed. The USIM is modelled by using an approximate and an accurate model. In the approximate model the refined Kloss formula is used and ideal converter supplying the USIM is assumed. In the accurate model the electric transients in the USIM and the harmonics in the output of the PWM converter are also taken into account.