With the development of high-power electric drive technology such as electric vehicles, maglev trains and ship electric power, people are beginning to demand increasingly low-speed, high-torque density and direct drive motors to reduce the size, weight and raw materials of motors. Consumption, improve material utilization. However, for a motor of the conventional structure, since the tooth portion flowing through the magnetic flux and the armature winding flowing through the current occupy the same cross section, there is a contradiction between increasing the air gap flux and increasing the current density of the winding, that is, the magnetic flux and the current density. The product has a certain limit, and it is difficult to obtain a fundamental increase in the output torque. The transverse magnetic field motor solves this problem theoretically.
TFM) is a new type of motor structure proposed by the famous German motor expert Professor H. Weh in the late 1980s. Unlike the traditional motor magnetic circuit structure, the main magnetic circuit of TFM is perpendicular to the direction of motor motion, realizing magnetic Decoupling of the circuit and circuit structure, the magnetic circuit size and the coil window can be changed as needed to adjust the magnetic flux and current density to obtain a higher torque density. After the first prototype of the 45kW Transverse Magnetic Field Permanent Magnet Motor (TFPM) was completed in Germany in 1988, the TFPM motor was funded and researched in 1999 as one of the preferred components for the development of electric vehicles in the future (the OKOFEH program); In 1997, the company successfully developed the first 3.0MW horizontal Delta Power Electronics Science and Education Development Fund (504925) for ship electric propulsion; in 1969, General Motors began to develop a transverse magnetic field permanent magnet motor for 30kW electric vehicles. In addition, the transverse magnetic field motor is also developing in the low-speed direct drive and servo field of medium and small power. At the same time, the transverse magnetic field motor also has great reference for linear drive and magnetic levitation technology, so it has high theoretical research and application value.
At present, the transverse magnetic field motor has a variety of topological structures, which can be roughly divided into three types: polymagnetic type, flat type and switched reluctance type, among which the magnetic magnetic torque density is the highest. It is a schematic structural diagram of a typical structural shape of a transverse magnetic field permanent magnet motor.
The stator of the TFPM motor adopts a combined stator structure, that is, the stator core is composed of an outer stator core, an inner stator core and a stator transition core, wherein the inner and outer stator cores are placed in parallel with the rotating shaft, and the half pole is staggered. The transitional iron core is placed in a ring shape perpendicular to the rotating shaft, and is connected with the inner and outer stator cores to form a closed magnetic circuit. A plurality of such unit pole cores are placed along the circumference to form a phase stator core, so that the combination is convenient; the armature The winding is a ring-shaped concentrated winding, which is convenient to be wound and has few ends, and is placed in parallel with the transition iron core; the rotor is composed of a core punching piece and a permanent magnet magnetic steel, wherein the iron core punching piece is fan-shaped and axially stacked, and the permanent magnet is cut along the axial direction. The magnetization is magnetized, and the adjacent two magnetic steels are opposite in polarity, and the magnetic steel and the iron core are alternately arranged to form a bilateral polymagnetic rotor structure, as shown by b. It works like the Weh prototype.
The structure of the two-phase TFPM motor is based on the three-dimensional magnetic field analysis plane of the equivalent magnetic network. When the influence of the end leakage is ignored (except for the disc motor), the finite element analysis can often be simplified for the two-dimensional field. The TFPM motor is not the same, and its main magnetic circuit is perpendicular to the direction of motion of the motor, which is a three-dimensional field problem, thus increasing the difficulty of analysis. This paper introduces a three-dimensional electromagnetic field analysis method-three-dimensional equivalent magnetic network method (3D is to concentrate the magnetic potential generated by the ring winding in the winding window and use a permanent magnet to be equivalent, which becomes a non-rotating field and satisfies rotH=0. The condition cites the scalar magnetic position and performs hexahedral splitting on the solution area, so it has the advantages of convenient splitting, strong intuitiveness, good convergence, etc. In the magnetic field analysis, the magnetic circuit between the phases and poles of the TFPM motor is independent. The periodic boundary conditions can be used to perform magnetic field analysis only on the unit poles indicated by b. The network section uses the cylindrical coordinates, and the radial direction of the motor is defined as the r-axis, which is divided into 28 nodes; The rotation direction is set to 0 axis, and 37 nodes are divided. The mechanical angle is 1 node every 1°, the axial direction is z axis, 17 nodes are divided, and a is the axial projection of the split, b A radial projection map for the split.
The three-dimensional meshing diagram shows the three-dimensional distribution of the bilateral air gap magnetic density when the prototype is in the position shown. It can be seen that due to the rotor magnetism structure, the air gap of the prototype is higher, which can reach 1.23T. At the same time, both the inner and outer air gaps participate in energy conversion, and the magnetic field utilization rate is high.
By calculating the different rotor positions and different currents, various characteristic curves of the prototype can be obtained. The middle dotted line shows the static electromagnetic torque characteristic curve obtained by calculating the Maxwell tension on the air gap interface at a current of 10A. It should be noted that due to the influence of the self-positioning torque of the permanent magnet, the electromagnetic torque appears in some conventional motors because the main magnetic field is in the same direction as the motor movement direction. This can be suppressed by using a multi-phase structure or the like. Lnet U) Outside air Wifi dense distribution (b) Internal gas fit Magnetic density distribution No-load air gap Magnetic density Three-dimensional distribution Static torque curve 5 Prototype static torque test Based on the above analysis, we designed and fabricated a combined stator bilateral magnetic TFPM Test prototype. The main design data of the prototype is: test curve, it can be seen that the test curve and the three-dimensional electromagnetic field calculation results are basically consistent, indicating the correctness of the above magnetic field analysis, which lays a good software platform for the further study of the transverse magnetic field permanent magnet motor. We also designed a TF>PM motor control system based on ADMCF340DSP and built a test platform for further research.
6 Conclusion The transverse magnetic field permanent magnet motor has the characteristics of high torque density, flexible design and convenient control. It is especially suitable for occasions requiring low speed, high torque and direct drive. In this paper, a new topology TFPM motor is proposed, which adopts the combined stator and bilateral magnetic rotor structure. It has the characteristics of simple structure, convenient processing and high magnetic field utilization. It introduces its structural characteristics and is equivalent to three-dimensional. The magnetic network method was used to analyze the magnetic field of the prototype, and the prototype was made. The preliminary experiment was carried out on the prototype. The test results of the prototype are basically consistent with the theoretical analysis, which proves the correctness of the above analysis method. At present, the transverse magnetic field motor has not been studied in China in more depth. I believe that the above work will lay a certain foundation for China's research in this field.
Special Bongs,Non Breakable Glass Bong,Rig Glass Bongs,Pure Glass Gravity Bongs
Cangzhou Dingyi Crafts Glass Products Co. Ltd. , https://www.dyglassbongs.com