Speaker
Description
Tubular flux-switching permanent magnet motor (TFSPMM) is a special kind of permanent magnet machine with the permanent magnet (PM) installed on the stator side and there is no winding or PMs on the mover side. Among various kind of linear machines, TFSPMM draws a great interest from researchers for its robust structure, high drive force density and low material cost required. Compared with the other linear machines, TFSPMM’ tubular structure avoids the motor thrust fluctuation caused by transverse side effect. However, the TFSPMM is opened at two ends, which will destroy the integrity of the magnetic circuit. The end effect can bring the TFSPMM with higher cogging force, higher force ripple and un-symmetry of the PM flux linkage especially when phase A and phase B has the end winding, and the problems will bring difficulties to the stable output and control of the motor. Based on these situations, this paper proposes a new unequal stator teeth method for the reduction of end effect. On the premise of not changing the volume of the motor, the end effect of the motor can be weakened by coordinating the axial length of the stator yoke and the axial length of the adjacent permanent magnets, so as to improve the symmetry of the three-phase permanent magnet flux linkage and reduce the cogging force. The calculation results are mainly based on the analysis of the average value and peak-to-peak value of the A-phase permanent magnetic flux linkage, because the A-phase and B-phase windings are symmetric in position and contain the end windings. To reduce the calculation load, the main electromagnetic parameters and performance of TFPMM are obtained based on using the 2D finite element method (FEM), and the model is built around the Z-axis, and the software defaults to rotate 360 degrees around the Z-axis.
