Simulation and analysis of starting transients in rotor-chopper-controlled doubly-fed induction motors

The direct starting of induction motors may cause various problems such as high inrush currents, voltage dips and harmonics. There have been numerous methods proposed to mitigate these stresses that are imposed on the power grid. This paper considers a starting method based on external rotor resistance control scheme that is used with wound-rotor induction machines. The so-called rotor-chopper-controlled topology is used to start an induction machine with maximum torque. The Automated state model generation (ASMG) algorithm is used to implement detailed switching model of the system in MATLAB/Simulink. Computer studies of a typical high power induction machine demonstrate that the machine start-up currents and the total energy consumption are significantly reduced while the induced electromagnetic torque is greatly increased with the rotor chopper controller applied.