Performance of a new brushless synchronous generator with an embedded induction machine to regulate excitation

This paper presents the performance of a brushless synchronous generator. This is a unique generator where an induction machine (IM) provides the controlled excitation to the field of a synchronous machine (SM) to regulate it's terminal voltage. Both the machines are put together in the same frame. Therefore, the stator and rotor accommodate two windings each. For the proposed machine, two windings need to be of different number of poles to earn magnetic decoupling. For this work, the synchronous and induction machines are wound for 2 and 6 poles respectively. The operation of IM is controlled to generate high frequency rotor current that can be rectified using a rotating rectifier. This paper first investigates the performance of the synchronous machine when the induction machine operates in motoring, generating and plugging modes. Following this, the plugging mode operation of IM is further exploited for satisfactory performance of the SM. Extensive simulations are carried out using MATLAB/Simulink. Experimental results are provided from a laboratory prototype to validate the principle of operation of the proposed generator.