The brushless DC motor is a typical mechatronics product consisting of a motor body and a driver. It is a motor without brushes and commutators, also known as a commutatorless motor. The brushless DC motor uses power electronics technology (such as frequency converters) to input AC signals to the motor, and replaces the traditional mechanical commutation method with electronic commutation, thereby avoiding the wear of the brushes and commutators and the resulting spark problems. This type of motor usually uses self-controlled operation, does not require additional starting windings on the rotor, and will not oscillate or lose steps when the load suddenly changes, making it more stable and reliable during operation.

The working principle of brushless DC motors is based on the fact that energized conductors generate magnetic fields, which have the characteristics of like attracting and opposite repelling. ‌ When the stator is energized, the energized coil will generate a magnetic field, and the rotor (permanent magnet) will be attracted or repelled by the magnetic field, thereby generating a rotating motion. In order to make the motor rotate continuously, it is necessary to detect the position of the rotor in real time, and control the direction of the current according to the position information, so that the magnetic field generated by the stator interacts with the magnetic field of the rotor, thereby achieving continuous rotation of the motor.

‌1.High efficiency and high benefit‌: Brushless DC motors are characterized by high efficiency and high efficiency. They are generally more efficient than traditional brushed motors, capable of providing higher power output and lower energy consumption. This makes them excel in applications that require high power output, such as electric vehicles, industrial robots, and computer peripherals.

‌2.Low noise and low maintenance cost‌: Brushless motors have low friction, low noise, and smooth operation due to the lack of brushes. This not only reduces noise pollution, but also extends the service life of the motor and reduces maintenance costs. The maintenance of brushless motors is mainly focused on dust removal, reducing the need to regularly replace brushes and other wear parts.

‌3.Wide application‌: Brushless DC motors are widely used in various fields, including home appliances, automobiles, industrial equipment, and robots. Their high efficiency and long life make them the first choice for many applications, especially where high reliability and long life are required.

‌4.Technological progress and future development: With the development of digital control and sensorless technology, the performance and reliability of brushless DC motors are constantly improving. These technological advances make brushless motors more advantageous in terms of total system cost, size and reliability, further promoting their application and development in various fields.

‌1.Specification selection: Select the appropriate motor specifications according to actual needs. In situations where the power supply voltage is adjustable, you can choose a DC motor specification with torque and speed close to the corresponding rated values ​​of the product, and get the required speed by changing the voltage; in situations where the power supply voltage is fixed, if there is no appropriate brushless DC motor available, you can first select the appropriate specification according to the torque, and the voltage and speed of the product can be adjusted appropriately.

‌2.Power selection: It is very important to reasonably select the power of the motor. If the power selection is too small, the load exceeds the rated output power, which will cause the motor to be overloaded, resulting in heating, vibration, speed drop, abnormal sound, etc. In severe cases, the motor may even be burned; while excessive power will cause economic waste.

‌3.Type selection: It is preferred to use ferrite permanent magnet DC motors with high efficiency, low price and low temperature rise. Only in occasions with strict performance requirements, small size and high ambient temperature, should aluminum nickel cobalt permanent magnet DC motors or rare earth permanent magnet DC motors be considered.

‌4.Voltage selection: It is very important to choose the correct voltage. The rated voltage should be selected according to the needs of the customer to select the driver voltage parameters. Note that the voltage used should not exceed the range specified by the driver during no-load and full-load processes.

‌5.Peak current selection: The method of selecting the peak current is that the rated input current Ir (A) of the motor is known, then the peak current Ip (A) >= 2xIr. Or if the rated output power Pr (W) and drive voltage Vr (V) of the motor are known, then the peak current Ip (A) = 4xPr/Vr.

‌6.Parameter setting‌: Set appropriate parameters according to different motors, and consider the temperature range. The wider the temperature range, the higher the price. In addition, the driver brake of the brushless motor adopts motor-end short-circuit brake. The higher the speed, the greater the braking force, but the braking current cannot be controlled. Therefore, the speed cannot exceed the safe braking speed during braking, otherwise the power tube may be burned out.

‌7.Power supply insulation requirements‌: To ensure the normal operation of the driver, the insulation resistance between the Hall wire ground wire of the motor and the motor winding wire, and the Hall ground wire winding wire and the casing should be greater than 100 megohms 500VDC, and can withstand 600VAC/50Hz/1mA/1 second withstand voltage without breakdown.

‌8.Structural type selection‌: Brushless DC motors can be divided into two types: inner rotor and outer rotor. The inner rotor motor has a small diameter and fast speed, which is suitable for high-speed applications; the outer rotor motor has a large diameter and good heat dissipation, which is suitable for low-speed applications.

Source:https://plaza.rakuten.co.jp/stovenstepper/diary/202410240000/