Brushless direct current motor (brushless DC motor) is a typical mechatronics product consisting of motor and drive. Brushless motor, also named commutatorless motor, is motor without brush or commutator(or collector ring). The three-phase symmetrical star connection method is often used in the stator winding of motor, which is similar to three phase asynchronous motor. The rotor of gear motor is stuck with a magnetized permanent magnet. To test the polarity of rotor for motor, there is a position sensor installed in the motor. The drive is made up of power electronics and integrated circuit, with the functions of accepting start-up, stop and braking signals from motor to control corresponding motion of motor, accepting signals of position sensor and cw&ccw to control on-off of each power tube of inverter bridge, generating continuous torque, accepting signals of speed command and velocity feedback to control and adjust the speed, provide protection and display.
Brushless DC motor can be used with gear reducer. This integrated assembly product is brushless DC gear motor , also called gear reduction motor. The function of gear motor is providing low speed and high torque. Meanwhile, different reduction ratio of gear motor can provide different speed and torque, which greatly improves the utilization rate of brushless DC motor in automation industry.
The characteristics of brushless DC motor:
- Can replace speed regulation of direct current motor, inverter plus inverter motor and Asynchronous motor plus reducer.
- Has features of traditional direct current motor, while cancel the structure of carbon brush and slip ring.
- Can run in low speed and high power, saving reducer and drive large load directly.
- Small size, light weight and strong driving force.
- Excellent torque characteristics, which leads to good performance in medium and low speed, high starting torque and low starting current
- Has infinite torque regulation, wide speed regulation range and strong overload capacity.
- Soft start and soft stop and good braking characteristics, can save the original mechanical braking or electromagnetic braking device
- great reliability, stability and adaptability, easy to maintain .
- Bump and vibration resistance, low noise, smooth running ,long service life.
- no sparks, suitable to explosive occasion for it’s explosion-proof.
- Trapezoidal wave magnetic field motor and Sine wave magnetic field motor are alternative according to requirements
- High efficiency,the motor itself has no excitation loss and carbon brush loss. The comprehensive electricity saving rate can reach 20%~60%.
The application of brushless DC motor:
Field of office computer equipment and consumer electronics
This is the field where brushless DC motor is the most widely used . brushless DC motor can be seen in the driving control of main shafts and accessory movements of devices like printer, fax machine, duplicator, HDD, floppy drive, movie camera and tape recorder which are common in our life.
Industry control field.
Following the development of technology and research on brushless DC motor, The application range of brushless DC motor in industry manufacturing expands and gradually becomes the development mainstream of industrial motors. There has been significant benefits in research and try on reducing production cost and improving running efficiency. Many manufacturers provide motor in different size to meet the needs of different drive systems. Brushless DC motor involves in industry manufacturing including textile,metallurgy, printing, automatic production line and numerical control machine tool at the present stage.
Field of medical equipment
The application of brushless DC motor is normal, being used to mini blood pump that drives artificial heart. In China, apply brushless DC motor to high speed centrifuge for high-speed surgical instruments and infrared laser modulator for thermal imager and thermometer.
Automobile field
A normal family car needs 20-30 permanent magnet motors, while a luxury car needs 59. Besides core engine, motor can be seen in components like wiper, electric door, automobile air conditioner and power window. With the automobile industry developing towards energy conservation and environmental protection, the motor used need to meet the standards of high efficiency and low energy consumption. Brushless DC motor with features of low noise, long service life, no sparks , convenient centralized control can satisfy requirements above. Following the development of speed regulation technology, brushless DC motor will have wider application on automobile industry.
Smart home field
Frequency conversion technology which has been popularized occupies most of consumer market as the symbol of home application. Receiving the favor of manufacturers, DC frequency conversion has tendency to take the place of AC frequency conversion. Intrinsically, the transform is transition of electric motors used in household appliances from induction motors to brushless DC motors and their controllers, meeting the requirements of energy conservation, environmental protection, low noise and high comfort. The developing direction of brushless DC motor is the same as that of technology including power electronics, sensor and control theory. Brushless DC motor is the product of a combination of various technologies, and its development depends on the innovation and improvement of the technologies associated with it.
