Self-tuning adaptive copper-losses minimization control of externally excited synchronous motors

With a high power density and a high efficiency, externally excited synchronous motors become an attractive alternative for traction applications. The loss minimization control of the motor drives is a complex task because of the variations of the motor parameters. To overcome the problem, this paper presents a self-tuning adaptive control method for externally excited synchronous motor drives. First, based on the method of Lagrange multipliers, an analytic solution is found to minimize copper losses. Next, a simple search control algorithm is suggested to combine with the analytic solution in order to overcome the problem of the parameter variations, caused by the magnetic saturation. The proposed method is verified by simulations. Several comparisons of results between proposed method and another conventional method show improved performances.