Brushless DC motors do not require brushes and commutators, can solve space-constrained system designs, and do not need to worry about general wear, sparks and noise, provide good control, and provide variable speed control for specific applications in automobiles. Brushless DC motors can also improve fuel efficiency and save energy. DC brushless motors have the following applications in automobiles:
1.Automotive purifier adopts brushless DC motor
Most car purifiers use DC brushless motors to drive centrifugal fan blades to discharge dirty air. The motor body is determined according to the motor circuit scheme, and a two-phase bridge commutation drive circuit is commonly used. The inner stator winding can be wound on the core teeth more conveniently. The motor is made into an outer rotor structure, and the stator and stator windings are placed inside the rotor. The commutation drive circuit uses an application specific integrated circuit (ASIC), which is simple in circuit and has control and protection functions.
2.Brushless DC motor for automobile air conditioner
The development of a low-voltage, high-current brushless DC motor for automotive air conditioners can solve the shortcomings of the original brushed DC motors, such as high noise, short life, and difficult maintenance, and improve electromechanical operation. Its rated voltage is 12V. Due to the limited structure, it makes it difficult to design a DC brushless motor. The stator punch is a 12-slot structure. Because it is a low-voltage and high-current type, in order to ensure that the current density is not too high, double wires are used to reduce the diameter of the wire. The rare-earth permanent magnet material Nd-Fe-B is selected because of its high remanence and coercive force and short magnetization direction. Therefore, the permanent magnet adopts a radial tile type. Select Hall element as the position sensor. Installed on the inner surface of the motor end cover, the magnetic field of the position sensor is an axial magnetic field.
3.Brushless DC motor for automobile driving
At present, the types of motors for vehicle driving can be roughly divided into four categories: DC motors, AC motors, brushless DC motors, reluctance motors, etc. According to practice, brushless DC motors have obvious advantages. The four wheels of an electric vehicle are driven directly by four independent wheeled motors. The inverter is used for electronic commutation, and the mechanical commutator and brushes are eliminated. This structure facilitates high-speed operation and does not affect the motor body when changing tires. The use of an external rotor motor that eliminates gears and directly drives is a relatively advanced solution in today's international vehicle driving motors. However, the design of the outer rotor motor is directly related to the design of the wheel structure of the vehicle. Therefore, at present, the domestic and foreign development of prototype vehicles has low funding and tight time. Many manufacturers basically choose internal rotor brushless DC motors. In addition, the disc type permanent magnet brushless DC motor has a large torque at low speeds, which can win the drive of front or rear wheels in electric vehicles, thereby eliminating the need for a mechanical transmission. It has the characteristics of compact axial structure, convenient installation, low noise, reliable operation and stepless speed regulation. The air-gap magnetic field is axial, the stator windings are composed of radiating conductors, and the rotor is composed of fan-shaped permanent magnets N and S, which are alternately assembled in disc yoke. The sticking point of the electromechanical technique lies in the forming technique of the disc winding. The process is complicated and the cycle is long, in order to improve the production efficiency. It is possible to change the epoxy resin used as supplementary material for insulation to thermosetting material and adopt the heating molding process.