Improvement of the magnetizing inductance of a moving transformer integrated in the end teeth of a linear synchronous motor

Permanent magnet linear synchronous motors (PMLSM) are applied evermore in industrial applications where direct linear motion is required. The majority of the machines are of the moving coil type, i.e. the coils on the mover of the motor are energized by means of moving cables. These moving cables cause undesired dynamical distortion in the system. Moreover, in high power applications the additional mass of the cables has to be taken into account in the design of the motor. This may lead to bulkier and more power consuming motors than strictly necessary for solely actuating the load. Contactless energy transfer (CET) circumvents these problems. The transfer of electrical energy through inductive coupling for linear motion has been the topic of several publications [1-4]. However, for cored application, all of them have a modular approach. Either, the contactless energy transfer and motor are two separate systems [1,4] or both functions are integrated in a single machine, but it can only operate in the energy transfer mode or motor mode [2]. An integrated solution is presented in [3], but here a coreless transformer is applied. A topology with a magnetic core that can run in both modes simultaneously was presented in earlier work [5], where two high frequency transformers are integrated in the end teeth of a PMLSM. The proposed topology in [5], however, suffers from a relatively poor magnetic coupling due to the high reluctances of the two air gaps in each core. The proposed topology of [5] is shown in Fig. 1. This paper shows how the performance of the transformer can be improved by adapting the shape on the air gap.