A brushless electric motor with a transverse magnetic flux and disk rotor

Abstract

Brushless permanent magnet machines (BPMMs) have a greater efficiency and smaller overall dimensions than do other types of machines and are widely used in electric drives for various purposes. Two types of BPMMs are used in practice: BPMMs with a classical double-layer-distributed stator winding and BPMMs with a toothed-step stator winding. There exists another type of BPMM with a transverse magnetic flux (transverse flux motors, TFMs) which is being actively studied. In TFM electric motors, the magnetic lines of fluxes of the poles of rotor end perpendicular to the direction of rotor rotation. Stator windings in these machines are fabricated as rings coaxial with rotor, and the magnetic circuit of stator consists of separate fragments. Specialists assert electric TFMs have a higher specific power—the ratio between the output power and the mass of the machine—than the electric motors of other type. They are of interest, first and foremost, for electric drives without reducing gears. In most TFM, only a half of the poles of rotor are magnetically connected with circular phases of stator. In this work, the TFM design with disk rotor is described, in which the magnetic flux of all poles of rotor is coupled to the circular phases of stator. The stator magnetic circuit in this machine consists of P-like elements, and alternation of polarity of these elements is provided due to the change of their position. As a result, the magnetic flux coupled to the circular phase increases doubles, as do the machine torque and power. Some results of modeling of a three-phase electric motor are presented. The results were obtained using the Ansys Maxwell computer code, including a graph of the change of torque on the shaft of a machine under rotation of the rotor under conditions of sinusoidal currents in phases.