Power Factor Improvement for a Magnetic-Geared Flat Linear Machine

The Magnetic-geared Flat Linear Machine (MGFLM) has the advantage of low material costs for long stroke applications. However, the relative low power factor of the MGFLM need to be improved. Through the derivation of the power factor equation, it is found that reducing the q-axis inductance would help to improve the power factor. The Halbach permanent-magnet arrays is adopted to reduce the harmonic components and increase the fundamental magnetic flux density of the MGFLM. Based on the FEA, the effects of every possible slot-pole combination and key dimensional parameters on the power factor and average thrust of the MGFLM are discussed. Compared to the original MGFLM, the power factor was effectively increased from 0.537 to 0.807 with a merely 3.3% loss in the average thrust.