An Optimal Excitation Control Technique for Brushless Induction Excited Synchronous Motor (BINSYM)

The popularity of electrified transportation is increasing exponentially day by day. Researchers are recently looking for a brushless and permanent magnet (PM)-less solution for electric vehicle motors. Wound-field synchronous motor (WFSM) is a suitable alternative to PM-based machines. The brushless induction excited synchronous motor (BINSYM) is a WFSM where the exciter, an induction machine (IM), is embedded inside a synchronous machine (SM) frame. The SM and IM are wound for different numbers of poles to achieve magnetic decoupling. The purpose of IM is to control the field current of SM. The IM is controlled in deep-plugging mode at a constant slip frequency over the entire speed range to minimize its reactive power demand. The SM is designed to operate at an extended speed range with a maximum speed-to-base speed ratio of 4.4. Since the rotor is of wound field type, the SM has the flexibility of reducing the field current. An efficiency maximization algorithm is proposed that sets the right magnitude of field current in SM. Simulation of BINSYM-based system has been carried out in MATLAB/Simulink to validate the control strategies. Experimental findings from the laboratory prototype machine closely match the simulation results.