Analytical study of magnetic field considering circumferential mover gaps in tubular linear oscillating motor

Tubular linear oscillating motor is applied to the linear electro-hydrostatic actuator system inside of more-electric aircraft. Benefited from a quasi-Halbach permanent magnet arrays, the motor performs with a good efficient and dynamic behavior. The radial magnetic flux in the air-gap produces the thrust of the machine, which is mainly generated by radial magnetized permanent magnet segments. Due to the complexity of fabrication, circumferential mover gaps exists between the radial polarized arrays. This paper proposed an analytical model based on equivalent surface current to calculate the distribution of magnetic flux in circumferential direction. Finite element model is used to confirm the accuracy of this model, and calculating results shows that circumferential gaps would cause volatility of the magnetic flux in air-gap, and the radial magnetized permanent magnets produces a more stable magnetic field than parallel magnetized ones with the same size of gaps. The proposed model is verified by experimental results.