Introduction of Disk-type Coreless Permanent Magnet Synchronous Generator (AFPMG/Maglev Generator)

Different from the radial flux structure of the traditional cylindrical generator, the disc permanent magnet generator is an axial flux generator. This kind of generator has short axial size, light weight, small volume and compact structure. Because the permanent magnet system is lossless, the generator has a high operating efficiency, and the stator and rotor are arranged in an equal manner. The stator winding has good heat dissipation conditions and can obtain high power density. Its most notable features are the small moment of inertia of the rotor, small electromechanical time constant, high peak torque and locked-rotor torque, stable low-speed operation, and superior dynamic performance.

The disc type permanent magnet generator combines the advantages of the disc type generator and the permanent magnet generator, and its rotor is a permanent magnet structure with a simple structure. Compared with the cylindrical generator, the disc permanent magnet synchronous generator can easily be made into a high-level logarithmic generator in terms of structure. Therefore, in occasions where a low-speed generator is required, the disc permanent magnet synchronous generator has a good application prospect.

Structure and principle

The armature winding of the disc type permanent magnet synchronous generator is radially distributed, and the effective conductor is located on the surface in front of the permanent magnet. When the permanent magnet is dragged by the prime mover to the synchronous speed, it will be generated in the armature in the air gap. The rotating magnetic field of the winding hinge induces an AC electromotive force in the armature winding.

The generator shell and the double-sided magnetic steel directly bonded to the shell form a double rotor, and the nail armature is placed in the middle of the double rotor to form a double air gap structure. As long as the stator is reasonably designed and manufactured accurately, the magnetic pulling forces acting on the two rotors during operation can be balanced with each other, so that the bearings are free from axial force and the service life of the generator is prolonged. The magnetic steel is directly bonded to the generator shell, so that there is no relative movement between the permanent magnet and the shell, which effectively reduces the eddy current loss of the generator. The generator winding adopts a slotless and iron-core structure, which can reduce the electromagnetic torque pulsation caused by the cogging effect and many disadvantages caused by the iron core. Moreover, because the armature winding has no iron core, there is no saturation problem in the magnetic circuit, which reduces the quality of the generator, reduces the loss, and increases the efficiency.