A new topology of hybrid synchronous machine

Permanent magnet (PM) synchronous machines are able to operate over a wide range of speeds at constant power through the use of control laws allowing for flux weakening. Generally, this is performed by applying a strong demagnetizing current in the d-axis, yet such an approach involves the risk of irreversible magnet demagnetization and, consequently, a reduction in machine performance. This paper presents a novel structure for a hybrid synchronous machine. Our solution provides good flux weakening without introducing the risk of magnet demagnetization. In order to explain the structure's operating principle, we apply a model with a single elementary design; EMF measurements are then presented to demonstrate the possibilities of flux weakening, along with a series of simulations to show the contribution of hybrid excitation.