Research On Fault Tolerant Operation Technology Of Magnetic Field Analysis Of AMB

Active magnetic bearings can stabilize the rotor in the desired position by controllable electromagnetic force,so as to achieve the rotor supporting effect similar to that of traditional bearings.In the traditional differential control,the magnetic bearing adopts the topological structure that the windings of two adjacent stator poles are connected in series to form a C-type magnetic pole pair,but when the design of the electromagnetic bearing is fault-tolerant,the scheme of magnetic pole independent drive is often adopted.At this time,the topological structure of the magnetic poles is more complex and diversified,and the magnetic poles drive different topologies,and the magnetic coupling between the magnetic poles is also very different,so the magnetic coupling between the magnetic poles is quite different.The study of magnetic coupling of AMB under different magnetic pole topologies is an important issue in the research of fault-tolerant control of AMB.From the point of view of magnetic field distribution,this paper mainly analyzes the influence of all-N-type,NNSS-type and NSNS topology AMB on rotor stable suspension under fault-tolerant control.Firstly,based on the working principle of traditional differential control and fault-tolerant control of active magnetic bearings,the electromagnetic resultant force formulas of active magnetic bearings with all-n,NNSS and nsns topologies are derived and calculated.The linearization is realized according to the generalized bias linearization theory The redundant structure of stator pole and power amplifier to maintain the normal operation of the AMB system is analyzed in detail.Secondly,according to the numerical analysis method used in the finite element analysis,an AMB model based on ANSYS is built,and on this model,the two-dimensional magnetic lines of force,two-dimensional magnetic flux density distribution and the magnetic flux density of the air gap between the stator and rotor of all n-type,NNSS type and nsns type topologies AMB rotor and stator without stator pole fault are simulated and analyzed,The results show that NNSS topology is easier to get better levitation performance in 8-stage independent drive control of fault-tolerant design of AMB.At the same time,the mathematical model of AMB is designed on the hardware in the loop simulation platform,and it is applied to the suspension experiment of NNSS and nsns topologies under differential control to realize the four degree of freedom suspension.Finally,the basic types of stator magnetic pole faults are summarized and it is found that when one or more stator magnetic pole faults occur in AMB,the current distribution matrix of the same fault can be obtained by mathematical operations such as matrix transformation according to the current distribution matrix of the basic stator magnetic pole fault type,which reduces the analysis of the amount of data.In addition,the current distribution matrix of AMB in the case of basic stator magnetic pole faults is deduced and calculated in detail,and the magnetic field distribution of three kinds of topology electromagnetic bearings under single and two stator magnetic pole faults is simulated and analyzed.The feasibility of the fault tolerance scheme of the electromagnetic bearing under the fault-tolerant control is verified and analyzed.