(10) By substituting equation (10) to the general Maxwell-type force equation for normal forces (11), the resultant forces can be concluded as comprising three contributions as shown in equation (12). (11) (12) Controllable excitation force FE prediction with a series of different PM thickness For self-bearing machines, the main contribution to the bearing force is also known as Maxwell normal force due to the interaction between PM field and armature winding field in the airgap region. The magnitude of resultant force represents the fundamental capability of magnetic bearing performance in terms of maintaining rotor position and avoiding the physical contact between rotor and stator. By keeping a constant armature winding field (mmf equals to 250A) in phase 1 of the leading design listed in Table 31, the magnitude of force variation (two-section combined value) with respect to magnet thicknesses in local x- and y-direction predicted from two-dimensional, non-linear finite element calculations is shown in Figure 310. Figure 310 Finite element predicted magnitude of phase-1 force variation with various magnet thickness ( in local x- and y-direction. As would be expected for phase 1, which is aligned along the x-axis, the local of force dominates over the y-component and is the main contributor to the bearing function, especially for small values of magnetic thickness. It is worth noting that the polarity of current in the stator produces an attractive force towards phase 1, i.e. it adds to the attractive force produced by the reluctance force produced by the interaction of the rotor core and the stator winding.
(10) By substituting equation (10) to the general Maxwell-type force equation for normal forces (11), the resultant forces can be concluded as comprising three contributions as shown in equation (12). (11) (12) Controllable excitation force FE prediction with a series of different PM thickness For self-bearing machines, the main contribution to the bearing force is also known as Maxwell normal force due to the interaction between PM field and armature winding field in the airgap region. The magnitude of resultant force represents the fundamental capability of magnetic bearing performance in terms of maintaining rotor position and avoiding the physical contact between rotor and stator. By keeping a constant armature winding field (mmf equals to 250A) in phase 1 of the leading design listed in Table 31, the magnitude of force variation (two-section combined value) with respect to magnet thicknesses in local x- and y-direction predicted from two-dimensional, non-linear finite element calculations is shown in Figure 310. Figure 310 Finite element predicted magnitude of phase-1 force variation with various magnet thickness ( in local x- and y-direction. As would be expected for phase 1, which is aligned along the x-axis, the local of force dominates over the y-component and is the main contributor to the bearing function, especially for small values of magnetic thickness. It is worth noting that the polarity of current in the stator produces an attractive force towards phase 1, i.e. it adds to the attractive force produced by the reluctance force produced by the interaction of the rotor core and the stator winding.
Chenyu%20Nie%20Thesis%20%28Final%20version%29.docx