Disc motor features
Disk permanent magnet motor, also known as axial flux motor, has many advantages compared with the traditional permanent magnet motor. At present, the rapid development of rare earth permanent magnet materials, so that the disk permanent magnet motor is more and more popular, some foreign advanced countries began to study the disk motor from the early 1980s, China has also successfully developed a permanent magnet disk motor.
Axial flux motor and radial flux motor have basically the same flux path, both of which are emitted by the N-pole permanent magnet, passing through the air gap, stator, air gap, S pole and rotor core, and finally returning to the N-pole to form a closed loop. But the direction of their magnetic flux paths is different.
The direction of the magnetic flux path of the radial flux motor is first through the radial direction, then through the stator yoke circumferential direction closed, then along the radial direction to the S-pole closed, and finally through the rotor core circumferential direction closed, forming a complete loop.
The whole flux path of the axial flux motor first passes through the axial direction, then closes through the stator yoke in the circumferential direction, then closes along the axial direction to the S pole, and finally closes through the circumferential direction of the rotor disk to form a complete loop.
Disc motor structure characteristics
Usually, in order to reduce the magnetic resistance in the magnetic circuit of the traditional permanent magnet motor, the fixed rotor core is made of silicon steel sheet with high permeability, and the core will account for about 60% of the total weight of the motor, and the hysteresis loss and eddy current loss in the core loss are large. The cogging structure of the core is also the source of electromagnetic noise generated by the motor. Due to the cogging effect, the electromagnetic torque fluctuates and the vibration noise is large. Therefore, the volume of the traditional permanent magnet motor increases, the weight increases, the loss is large, the vibration noise is large, and it is difficult to meet the requirements of the speed regulation system. The core of the permanent magnet disk motor does not use silicon steel sheet and uses Ndfeb permanent magnet material with high remanence and high coercivity. At the same time, the permanent magnet uses Halbach array magnetization method, which effectively increases the "air gap magnetic density" compared with the radial or tangential magnetization method of the traditional permanent magnet.
1) The middle rotor structure, composed of a single rotor and double stators to form a bilateral air gap structure, the motor stator core can generally be divided into slotted and not slotted two kinds, with slotted core motor in the processing of rewinding bed, effectively improve material utilization, motor loss reduction. Because of the small weight of the single rotor structure of this kind of motor, the moment of inertia is minimum, so the heat dissipation is the best;
2) The middle stator structure is composed of two rotors and a single stator to form a bilateral air gap structure, because it has two rotors, the structure is slightly larger than the middle rotor structure motor, and the heat dissipation is slightly worse;
3) Single-rotor, single-stator structure, the motor structure is simple, but the magnetic loop of this kind of motor contains the stator, the alternating effect of the rotor magnetic field has a certain impact on the stator, so the efficiency of the motor is reduced;
4) Multi-disc combined structure, composed of a plurality of rotors and a plurality of stators alternate arrangement of each other to form a complex plurality of air gaps, such structure motor can improve the torque and power density, the disadvantage is that the axial length will increase.
The remarkable feature of the disk permanent magnet motor is its short axial size and compact structure. From the design point of view of permanent magnet synchronous motor, in order to increase the magnetic load of the motor, that is, to improve the air gap magnetic flux density of the motor, we should start from two aspects, one is the selection of permanent magnet materials, and the other is the structure of the permanent magnet rotor. Considering that the former involves factors such as the cost performance of permanent magnet materials, the latter has more types of structures and flexible methods. Therefore, Halbach array is selected to improve the air gap magnetic density of the motor.
Hangzhou Magnet Power Technology Co., Ltd. is producing magnets with Halbach structure, through the different orientation of the permanent magnet arranged according to a certain law.The magnetic field on one side of the permanent magnet array is significantly enhanced, easy to achieve the spatial sine distribution of the magnetic field. The disk motor shown in Figure 3 below is developed and produced by us. Our company has a magnetization solution for axial flux motor, which can be integrated online magnetization technology, also known as "post-magnetization technology". The core principle is that after the product is formed as a whole, the product is treated as a whole by one-time magnetization through specific magnetization equipment and technology. In this process, the product is placed in a strong magnetic field, and the magnetic material inside it is magnetized, thereby obtaining the desired magnetic energy characteristics. The on-line integral post-magnetization technology can ensure the stable magnetic field distribution of the parts during the magnetization process, and improve the performance and reliability of the products. After using this technology, the magnetic field of the motor is more evenly distributed, reducing the additional energy consumption caused by the uneven magnetic field. At the same time, due to the good process stability of the overall magnetization, the failure rate of the product is also greatly reduced, which brings higher value to customers.
Application field
- The field of electric vehicles
Drive motor
The disk motor has the characteristics of high power density and high torque density, which can provide large output power and torque under small volume and weight, and meet the requirements of electric vehicles for power performance.
Its flat structure design is conducive to realizing the low center of gravity layout of the vehicle and improving the driving stability and handling performance of the vehicle.
For example, some new electric vehicles use a disc motor as a drive motor, enabling rapid acceleration and efficient driving.
Hub motor
The disk motor can be directly installed in the wheel hub to achieve the hub motor drive. This drive mode can eliminate the transmission system of traditional vehicles, improve transmission efficiency and reduce energy loss.
Hub motor drive can also achieve independent wheel control, improve vehicle handling and stability, while also providing better technical support for intelligent driving and autonomous driving.
- Industrial automation field
Robot
In industrial robots, the disk motor can be used as a joint drive motor to provide precise motion control for the robot.
Its characteristics of high response speed and high precision can meet the requirements of fast and accurate movement of robots.
For example, in some high-precision assembly robots and welding robots, disk motors are widely used.
Numerical control machine tool
Disc motors can be used as spindle motors or feed motors for CNC machine tools, providing high-speed, high-precision machining capabilities.
Its high speed and high torque characteristics can meet the requirements of CNC machine tools for processing efficiency and processing quality.
At the same time, the flat structure of the disc motor is also conducive to the compact design of CNC machine tools and saves installation space.
- Aerospace
Vehicle drive
In small drones and electric aircraft, the disk motor can be used as a drive motor to provide power to the aircraft.
Its characteristics of high power density and light weight can meet the strict requirements of the aircraft power system.
For example, some electric vertical take-off and landing vehicles (eVTOL) use disk motors as a power source for efficient, environmentally friendly flight.
- The field of home appliances
Washing machine
The disk motor can be used as the driving motor of the washing machine, providing efficient and quiet washing and dehydration functions.
Its direct drive method can eliminate the belt transmission system of traditional washing machines, reducing energy loss and noise.
At the same time, the disk motor has a wide speed range, which can realize the needs of different washing modes.
air conditioner
In some high-end air conditioners, disk motors can act as fan motors, providing strong wind power and low noise operation.
Its high efficiency and energy saving characteristics can reduce the energy consumption of air conditioning and improve the performance of air conditioning.
- Other areas
Medical device
The disk motor can be used as a driving motor for medical devices, such as medical imaging equipment, surgical robots, etc.
Its high precision and high reliability can ensure the accurate operation of medical devices and the safety of patients.
- New energy power generation
In the field of new energy such as wind power and solar power generation, disk motors can be used as the driving motor of generators to improve power generation efficiency and reliability.
Its characteristics of high power density and high efficiency can meet the strict requirements of new energy generation motors.
Post time: Aug-28-2024
