3 Forms of Halbach Arrays and Their Applications
Linear array
Linear is the most basic form of Halbach array. This array magnet can be regarded as a combination of radial array and tangential array.
Linear Halbach arrays are currently mainly used in linear motors. The levitation principle of the maglev train is that the moving magnet interacts with the magnetic field generated by the induced current in the conductor to generate a levitation force, accompanied by magnetic resistance.
Improving the buoyancy-to-drag ratio is the key to improving the performance of the suspension system, which requires the on-board magnets to be light in weight, strong in magnetic field, uniform in magnetic field, and high in reliability.
The Halbach array is installed horizontally in the center of the car body, and interacts with the windings in the center of the track to generate propulsion, maximizing the magnetic field with less magnet usage, while the other side has less magnetic field, which can prevent passengers from being exposed to strong magnetic fields.
Circular array
The circular Halbach array can be regarded as a ring shape formed by combining the linear Halbach arrays end to end.
The permanent magnet motor using the Halbach array structure has an air gap magnetic field closer to the sinusoidal distribution than the traditional permanent magnet motor. Under the same amount of permanent magnet material, the air gap magnetic density of the Halbach permanent magnet motor is larger and the iron loss is smaller. In addition, the Halbach ring array is also widely used in permanent magnet bearings, magnetic refrigeration equipment and magnetic resonance equipment.
How to make andproduce a Halbacharray
Method 1: Depending on the topology of the array, use magnet glue to glue together pre-magnetized magnet segments. Due to the strong mutual repulsion between the magnet segments, a mold should be used to clamp them during adhesion. This method has low manufacturing efficiency and is more suitable for use in the laboratory research stage.
Method 2: A complete magnet is fabricated by filling or pressing, and then magnetized in a special fixture. The array structure processed by this method is similar to the following figure. This method has high processing efficiency and is relatively easy to achieve mass production. However, this method requires special design of magnetization fixture and magnetization process.
Method 3: Use a winding array of a specific shape to achieve a Halbach-type magnetic field distribution, as shown in the figure below.
