# Analysis of the hottest AC hybrid magnetic nonline

2022-08-23
• Detail

The AC hybrid magnetic is planned to be installed at the end of 2014. The nonlinear analysis

from equation (3), it can be seen that the levitation force FI is directly proportional to the quadratic power of the magnetic flux (air gap), and the control current and displacement determine the size of the magnetic flux at the air gap. Therefore, FI is actually only related to XY, IX, iy. Figure 7 (a) and figure 8 (a) show the force/current relationship curve clusters at different displacements (based on the finite element solid model of magnetic bearing, the nonlinear characteristics of magnetic bearing suspension force are analyzed with Ansoft software). In addition, based on the mathematical model of magnetic bearing, the force/current relationship curve clusters at different displacements under the same conditions are made with MATLAB software, as shown in Fig. 7 (1,) and Fig. 8 (1)

when Figure 7 (Tong) and Figure 7 (b) follow the direction shown by the arrow (the displacement of the rotor in the x-axis direction gradually changes from 0 to 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm), the current I, and the force F, f on the rotor. Relationship graph of. It can be seen from the figure that due to the influence of the cross coupling relationship between the radial two degrees of freedom, the relationship between the radial suspension force F and the control current I shows asymmetry. When the number of ampere turns changes from - 150 ampere turns to 150 ampere turns, the linearity of the curve is very good, and the magnetic bearing that controls this range can achieve better results. It can be seen that the linearity of the force/current relationship curve becomes worse as the offset of the rotor in the radial X direction increases. It is observed that when the rotor is offset at 0.4 mm in the radial X direction, the balance position improves the energy utilization efficiency of the plastic granulator process and prevents environmental pollution. The linearity is not very ideal, but when the offset occurs within 0.3 mm, the linearity of the balance position is still ideal. It shows that when the magnetic bearing works within a small air gap, in order to achieve excellent control effect, if the air gap of the magnetic bearing is relatively small, the purpose can be achieved without using a complex nonlinear controller. If the magnetic bearing works in the case of large air gap, compensation should be considered in the design of the controller. The nonlinearity caused by the air gap and the asymmetry caused by the three-level structure can be decoupled by using neural network inverse controller or segmented by using parameter white tuning fuzzy PLD control algorithm

Fig. 8 (a) and Fig. 8 (b) are the curves of the relationship between the current I and the rotor force F, F, in the direction indicated by the arrow (the displacement of the rotor in the v-axis direction gradually changes from O to o.1 mm, 0.2 mm, 0.3mm). It can be seen from the figure that the current I. When changing, not only the radial force F is generated., The force F, which is also generated in the negative direction of the X axis, controls the current I. When the ampere turns of F vary from a 150 ampere turn to 150 ampere turn, F, is very small, and the increase of F, is directly proportional to the increase of ampere turns as a graphene industry R & D demonstration base

to sum up, Figure 7 shows that the levitation force F, the control current I and the balance position are not symmetrical, which is closely related to the asymmetry of the structure (three poles) of the magnetic bearing. However, figure 8 shows that the levitation force F, and the control current I are symmetrical with respect to the horizontal corrosion resistance and impact resistance balance. Therefore, it can be concluded that when controlling the magnetic bearing, the difficulty of control in the X and Y directions is different. When adjusting the stable suspension of the magnetic bearing in the X direction, its control parameters will affect the control effect of the magnetic bearing in the V direction, while when controlling the rotor balance in the Y direction, changing its control parameters will not have any impact on the X direction

compared with FIG. 7 (Tong) and Fig. 8 (Tong), FIG. 7 (b) and Fig. 8 (Tong) are the force/current relationship curves in a completely ideal situation, but they can still reflect the trend of expressing the force/current relationship of this bearing. Compared with the simulation results based on the finite element solid model of magnetic bearing, similar results prove that the mathematical model of this magnetic bearing is accurate and close to the normal operation of this AC hybrid magnetic bearing

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