Brushless induction excited synchronous generator with induction machine operating in plugging mode

摘要

This paper proposes a new brushless and magnet-less synchronous generator that is controlled by an induction machine. The stators of synchronous and induction machine are put in the same structure but wound for different number of poles such that they remain decoupled. The rotors of synchronous and induction machines are placed in the same rotating structure wound for the corresponding number of poles (similar to the stator windings). Effectively the rotor windings are also magnetically decoupled. However, a rotating rectifier is used to rectify the rotor current of the induction machine and feed the excitation winding (i.e. rotor winding) of the synchronous machine. Thus by controlling the induction machine, the excitation of the synchronous machine can be smoothly controlled. This work investigates the performance of the synchronous machine when the induction machine operates in motoring, generating and plugging modes. Possible system configurations to operate in these modes are also proposed. A controller that operates the induction machine in plugging mode to regulate the terminal voltage of the synchronous generator is reported. Extensive simulations using MATLAB/Simulink are presented.