The unbalanced vibration of the rotor will seriously affect the stability and safety of the magnetic suspension switched reluctance motor (BSRM) in operation. On the basis of introducing the principle of generating the suspension force of the BSRM rotor, the dynamic equation of the rotor is derived. The decoupling control model of BSRM suspension force is given, and the unbalanced vibration compensation strategy of BSRM rotor is designed based on the idea of coordinate transformation by using the superior low-pass filtering characteristic of TD filter in ADRC. The unbalanced vibration of BSRM rotor is compensated dynamically in real time. The simulation results verify the effectiveness of the strategy. The method based on ADRC and coordinate transformation successfully compensates the unbalanced vibration of the BSRM rotor, and basically eliminates the influence of unbalanced vibration of the rotor on the BSRM system.
The performance of the control system is excellent. The magnetic suspension switched reluctance motor (BSRM), which is known as bearingless switched reluctance motor in literature, has analyzed and compared the similarity between the magnetic bearing structure and the stator structure of SR motor, which is developed by combining the advantages of both. BSRM integrates the winding that generates levitation force on the motor rotor and the stator winding of the motor, and integrates the magnetic field of the motor stator winding and the magnetic field of the motor levitation force winding into a whole. By studying the coupling and decoupling control of the torque force and the radial levitation force of BSRM, the normal rotation and stability of the BSRM rotor can be controlled independently. Suspension [1?5]. BSRM has no winding in its rotor, no deformation in the extreme speed environment, and strong fault tolerance. It has wide application prospects in the fields of electronics industry, chemical industry, life science and so on. However, practice shows that the eccentricity of the rotor can not be avoided due to the defects of mechanical processing of the motor rotor itself in the process of BSRM high-speed rotation, so the unbalanced vibration will occur when the rotor rotates at high speed, and the unbalanced vibration seriously affects the rotating accuracy of the rotor. Therefore, it is a very important subject to study the compensation of unbalanced vibration of BSRM suspension rotor. At present, the research on compensation of unbalanced vibration mainly focuses on controlling unbalanced vibration of rotor by increasing or reducing stiffness and damp of rotor. Increasing stiffness and damp of rotor can reduce and eliminate unbalanced vibration displacement of rotor, thermostatic element and reducing stiffness and damp of rotor can reduce and eliminate rotor. Unbalanced vibration force. In this paper, the unbalanced vibration of the rotor of the magnetic levitation switched reluctance motor is compensated by using the TD filter and coordinate transformation method in the ADRC. The AC displacement signal is converted to DC signal by coordinate transformation, and the excellent low-pass filtering characteristic of the TD filter is fully used to eliminate the inclusion. High frequency noise in DC signal [8?9], then the unbalanced vibration compensation signal is obtained by Inverse Coordinate transformation. The displacement signal is superimposed with the BSRM unbalanced vibration compensation signal, and the vibration signal is successfully eliminated from the displacement signal, so that the unbalanced vibration of the BSRM rotor can be reduced or even eliminated successfully. The simulation results show that the compensation control strategy designed is effective and feasible. Any rotating body will always produce unbalanced vibration [8]. Generally, the unbalance of a rotating body can be divided into two types: static unbalance and dynamic unbalance. The main reason for the static unbalance of the rotating body is the mass eccentricity. In Fig. 1, [C] is set as the mass center of the rotor, and [M] is set as both the axis of the rotor and the geometric center of the rotor. Setting [E] is the eccentricity caused by the misalignment of the mass center and the geometric center of the rotor. Formula (1) shows that the centrifugal force is proportional to the rotational speed [_2], and the centrifugal force will be transmitted to the base to cause the vibration of BSRM suspension system. When the inertia axis [q] of the rotor is not aligned with its rotating axis [O] in the same line, the angle difference [theta,] between the two axes will be formed. When the rotating body rotates at high speed, dynamic unbalance will occur, which will inevitably lead to vibration. It is the existence of imbalance that makes any object vibrate when it rotates at high speed. For the rotor system of the magnetic suspension switched reluctance motor studied in this paper, the stiffness of the rotor is very strong, and the protection devices of bearings are installed at both ends of the rotor. Therefore, the unbalanced vibration of BSRM rotor is mainly caused by static unbalance. Moreover, the unbalanced vibration will become stronger and stronger as the rotor speed increases. Once the vibration exceeds the bearing range of the rotor system, the dynamic characteristics and stable operation of BSRM system will be seriously damaged. Therefore, the destruction of unbalanced vibration has an important hazard to the stable operation of high-speed rotating body. In the formula, [e] is set as the eccentricity between the center of mass [C] and the axis [M], [?] as the initial phase angle. In the formula, the mass matrix [m = m1001], the damping matrix [C = cx00cy], the stiffness matrix [K = kx00ky], and the static gravity load [fFext=-22mg-22mg]. [xy = tan-12x x1-2xtan-12yy1-2y]. It can be seen from equation (7) that the dynamic rotation trajectory of the geometric center of BSRM rotor should be a point without mass eccentricity, but the dynamic rotation trajectory of the geometric center of BSRM rotor is ellipse under the influence of centrifugal force caused by mass eccentricity. Generally, the stiffness of BSRM rotors can be approximated in the direction of [x] axis and [y] axis, so that the dynamic rotation trajectory of [kx = ky,] BSRM rotors is circular. Tracking Differentiator (TD) is a special non-linear process analysis method, which is difficult to study with conventional non-linear frequency analysis method. However, once the tracking parameters of TD filter are given, even if the input signal frequency is very high, its tracking waveform can be regarded as a sine wave, and the frequency is the same as that of the input signal. Therefore, in the analysis of the frequency characteristics of TD filters, the introduction of linear system frequency characteristics analysis method will not lead to large errors. In the formula, [A = V alpha 1-x*a V alpha 2V alpha 22R] [sat (A, Delta 1) = sign (A), A (> Delta 1A Delta 1, A < Delta 1]. The second-order frequency characteristics of equation (8) are analyzed in detail in reference [10?11]. The results show that the second-order TD filter and the second-order linear low-pass filter have similar characteristics, but they are much better than the general linear system. When there is a small phase shift in the passband, no resonance phenomenon occurs. Because the vibration frequency of the rotor and the rotating speed of the rotor are both [_], it can be inferred that the displacement signal collected by the displacement sensor must contain the same frequency signal component as the rotating speed, and the synchronous vibration signal [xm, ym] can be extracted by fast Fourier transform. When the AC value of displacement signal is converted to DC value by coordinate transformation, some high frequency noise signals must be included in the DC value. The TD filter adopts the algorithm shown in Formula (8), which has good low-pass filtering function. It can filter high-frequency noise and get DC signal through coordinate transformation smoothly. Then, the unbalanced vibration compensation signal of BSRM rotor can be obtained by Inverse Coordinate transformation. By superimposing the displacement signal with the BSRM unbalanced vibration compensation signal, the vibration signal is successfully eliminated from the displacement signal, so as to reduce or even eliminate the unbalanced vibration of the rotor. Fig. 5 is a control block diagram of BSRM rotor vibration compensation. Taking the experimental prototype as the simulation object, the simulation experiment of BSRM rotor unbalance compensation control is carried out by using Simulink and fuzzy logic toolbox in matlab. In the simulation software MATLAB, the vibration signal is simulated by sinusoidal wave, and then the random noise signal is superimposed on the sinusoidal wave to obtain the displacement signal for simulation, as shown in Figure 6. The frequency can be dynamically adjusted according to the need of experiment. Setting frequency [f=] 250 Hz, i.e. [_=] 15 000 rad/min, [x] direction displacement signal is 90 degrees behind [y] direction displacement signal. From Figure 8, it can be seen that after filtering by TD filter, the DC signal changes from the original signal with obvious fluctuation to a smooth signal.
The DC signal is converted into AC signal by Inverse Coordinate transformation. Then the AC signal is actually a vibration signal separated from the displacement signal. Its frequency and speed are equal. The signal value is taken as the compensation signal of BSRM unbalanced vibration and then superimposed on the displacement signal. Formula (8) is used for Inverse Coordinate transformation, and the simulation results are shown in Figure 9. By analyzing and comparing Figure 9 and Figure 6, it is found that the signal in Figure 9 has successfully tracked the displacement signal, and has the same frequency and amplitude as the displacement signal, and the waveform is smooth. This signal is the same frequency as the rotational speed, which is the compensation signal of BSRM unbalanced vibration. The displacement signal is superimposed with the BSRM unbalanced vibration compensation signal, and the vibration signal is eliminated successfully.
The displacement signal no longer contains the vibration signal. The simulation results are shown in Fig. 10. From the simulation results, it can be seen that the vibration of the displacement signal is very small (less than 1um) after adding the compensation signal. It can be seen that the unbalanced vibration compensation control of BSRM rotor can be realized well based on TD filter and coordinate transformation vibration compensation strategy. In this paper, the unbalanced vibration compensation strategy of BSRM rotor is designed by using the good low-pass filtering characteristic of TD filter in ADRC and the idea of coordinate change. The simulation results show that the design of compensation control strategy is effective and feasible.