Brushless induction excited synchronous motor (BinSyM): A new motor for high power applications

Abstract

This paper introduces a new motor suitable for high power applications. Overall, the machine is brush-less and magnet-less and therefore having special merit for use in places where maintenance is crucial. This will be attractive in areas such as safety critical systems as well as off-shore wind turbines. The main motor-torque is produced through the locking of stator and rotor poles as in the synchronous machine, whereas the field-excitation is provided by utilizing the principle of induction. Thus, a synchronous and an induction machine are embedded in the same structure to make this happen. The stator and rotor house two windings each, one for the synchronous and another for the corresponding induction machines. These are wound for different number of poles to avoid any magnetic coupling. The rotor current of the induction machine is rectified through a rotating rectifier to feed the required dc current in the field winding of the synchronous machine. Controlled excitation can thus be produced avoiding use of brush and magnets. For the present investigation a 2-pole synchronous and 6-pole induction combination is considered, however the principle of operation is valid and work well for other combinations. A possible layout of the machine is presented and steady-state analysis has been carried out to select the suitable operating zone. Vector control algorithms for excitation machine and main synchronous machine have been reported. MATLAB/Simulink based simulation results are presented to clearly demonstrate the effectiveness and advantage of the proposed drive system.