Brushless direct current motors (brushless DC motors) are mechatronics products consisting of a motor and a drive. Brushless motors, also known as commutator-less motors, are motors without brushes or commutators (collector ring). The stator windings of the motor often use a three-phase symmetrical star connection, similar to a three-phase asynchronous motor. The rotor of the gear motor is stuck by magnetized permanent magnets. In order to test the polarity of the motor rotor, a position sensor is installed in the motor. The drive consists of power electronics and integrated circuits, with the function of receiving motor signals to start, stop and brake, controlling the corresponding actions of the motor. It’s also able to receive position sensor signals, and control on-off and cw & ccw. The power tube of the inverter bridge generates continuous torque, receives speed commands, and velocity feedback signals to control and adjust speed, provide protection, and display.
Brushless DC motors can be used with gear reducers. This integrated assembly product is a brushless DC gear motor, also known as gear reduction motor. The role of the gear motor is to provide low speed and high torque. Gear motors with different reduction ratios can simultaneously provide different speed and torque, which greatly improves the utilization rate of brushless DC motor in the automation industry.
The Characteristics of Brushless DC Motors:
- Replaces speed regulation of DC motor, inverter plus inverter motor and Asynchronous motor plus reducer.
- Has the features of a traditional DC motor, without a carbon brush and slip ring.
- Can run at low speed and high power, and directly drives large loads.
- Compact, lightweight, and strong driving force.
- High torque characteristics, which leads to good performance at medium and low speeds, high starting torque, and low starting current.
- Unlimited torque adjustment, wide speed adjustment range, and strong overload capacity.
- Soft start-stop and good braking characteristics can save the original mechanical braking or electromagnetic braking device.
- Great reliability, stability, and adaptability. Easy to maintain.
- Shock and vibration-resistant, low-noise, runs smoothly, long service life.
- No sparks, explosion-proof.
- Trapezoidal wave magnetic field motor and sinewave magnetic field motor can be selected according to needs.
- High efficiency. The motor itself has no excitation or carbon brush loss. The comprehensive electricity saving rate can reach 20-60%.
Applications of Brushless DC motor:
1. Office Computer Equipment & Consumer Electronics
This is an area where brushless DC motors are widely used. Brushless DC motors can be seen in the main shaft drives, and accessory movements in devices including printers, fax machines, copiers, HDD, floppy drives, movie cameras, and tape recorder.
2. Industry Control
With the development and research on brushless DC motor technology, the application range of brushless DC motors in industrial manufacturing continues to expand, and has gradually become mainstream in the development of industrial motors. Significant benefits have been achieved in research attempts to reduce production costs and improving running efficiency. Many manufacturers provide motors of different sizes to meet the needs of different drive systems. Brushless DC motor are currently involved in manufacturing industries including textiles, metallurgy, printing, automatic production lines, and numerical control machine tools.
3. Medical Technology
The application of the brushless DC motors is normal, and is used to drive the micro blood pump of the artificial heart. In China, brushless DC motors are used in high-speed centrifuges for high-speed surgical instruments, and infrared laser modulators for thermal imaging cameras and thermometers.
An ordinary family car needs 20-30 permanent magnet motors, while a luxury car needs 59. In addition to the core engine, motors can also be seen in components including wipers, electric doors, automobile air conditioners, and electric windows. With the development of the automobile industry heading in the direction of energy conservation and environmental protection, the motors used need to meet the standards of high efficiency and low energy consumption. Brushless DC motors with low-noise, long service life, no sparks, and convenient centralized control, can satisfy the aforementioned requirements. With the development of speed regulation technology, brushless DC motors will be more widely used in the automobile industry.
5. Smart Homes
Popular frequency conversion technology in household applications has occupied most of the consumer market. Favored by manufacturers, DC frequency conversion has a tendency to replace AC frequency conversion. Intrinsically, this transition is a transition from induction motors to brushless DC motors. Their controllers, which are used in motors for household appliances, meet the requirements of energy saving, environmental protection, low-noise and high comfort. The development direction of brushless DC motors is consistent with the development of power electronics, sensors, and control theory. The brushless DC motor is a product of a combination of various technologies, and its development depends on the innovation and improvement of related technologies.