Application of Brushless DC Motor and Development Trend of DC Brushless Motor Technology

Application of Brushless DC Motor and Development Trend of DC Brushless Motor Technology

Application of Brushless DC Motor

The 21st century is the century when permanent magnet brushless DC motors are widely used. According to the driving current mode, permanent magnet brushless DC motors can be divided into square wave drive and sine wave drive. The latter is also called synchronous permanent magnet AC servo motor, which is mainly used for servo control. The synchronous permanent magnet AC servo motor, which entered the practical stage only in the 1980s, is a new type of servo motor that can compete with the DC servo motor. According to the analysis of experts from the International Motor Conference, the DC servo motor is replacing the AC servo motor with an annual growth rate of 15%. The DC servo motor will occupy the first place, and its prospect is extremely good. Therefore, some motor experts in the world assert that the 21st century is a century in which permanent magnet DC brushless motor is widely used. Especially in the field of small motor, DC brushless motor will occupy a dominant position.

Now, due to the growth of market demand, for 3A (industrial automation, office automation, home automation), the power coverage of permanent magnet DC brushless motor has already broken through the micro motor power limit, from milliwatt level to tens of kilowatts. The main application fields include:

1. Application in computer peripheral equipment, office automation equipment and digital electronic consumer goods.

Single phase DC brushless motor fans have also been widely used in computer peripherals, office automation equipment and other automation instruments and equipment, squeezing out the original AC fan market.

2. Application in industrial drive and servo control

In the drive of military and industrial robots and manipulators, DC brushless motor is widely used. According to the International Federation of Robots (IFR), as of 2015, more than 1.5 million industrial robots have been used in industrial assembly line operations worldwide, more than 2.3 million will be used in the next three years, and 150 million robots will be used in service fields. Robot has become one of the main application fields of DC brushless motor.

3. Application in automobile industry

According to the analysis of the American market survey, 59 permanent magnet DC motors are required for each luxury car, and 20~30 for ordinary cars. On the other hand, automobile energy conservation has been paid more and more attention. The motor used for modern automobile needs to improve performance and efficiency. The flat disk structure is used to reduce space, increase output, eliminate spark interference, reduce noise, extend life, and facilitate centralized control. This is the specialty of DC brushless motor. It is predicted that the brushless DC motor used in automobiles will be replaced by the permanent magnet brushless DC motor.

4. Application in the field of medical equipment

For example, DC brushless motors are used in high-speed centrifuges, dental and surgical high-speed instruments, infrared laser modulators used as thermal imagers, thermometers, incubators, etc.

5. Application in household appliances

At present, variable-frequency household appliances represented by variable-frequency air conditioners, refrigerators and washing machines have gradually entered the consumer market in China. DC frequency conversion is a new improvement in energy saving, high efficiency, low noise, comfort, intelligence and other aspects of household appliances. The frequency conversion compressor manufacturers in China have started to use the so-called full DC air conditioning in compressors and indoor and outdoor fans, which will be more energy saving and comfortable.

6. Application in UAV

In recent years, the UAV market is booming, and the UAV related industry chain has ushered in new development opportunities. Among them, DC brushless motor is one of the important components of UAV, and its performance is directly related to the flight performance of UAV. In addition, under special environmental conditions, such as humid, vacuum and hazardous substances, DC brushless motor is used to improve the stability of the system. Among them, military and aerospace fields are the first fields where DC brushless motor is applied.

Development Trend of DC Brushless Motor Technology

1. Products are developing towards specialization and diversification.

Almost all DC brushless motor products are designed and manufactured for specific purposes. It is impossible to try to produce a general series of DC brushless motor to meet the ever-changing market demand. Various manufacturers design and manufacture various DC brushless motors with special structures and special purposes, and constantly innovate in design, structure and new technology of process to meet the needs of different machine markets.

New rotor magnetic circuit structures, such as permanent magnet materials with different performance parameters, surface bonding structures of tile type and ring type, and various embedded internal magnet structures with different designs, have emerged. There are various external rotors, axial air gap, slotless structure motors, linear DC brushless motors, etc.

2. Through structural and technological innovation, the products will be developed in the direction of low cost and low price with production automation and scale.

As the cost of electronic commutation circuit is higher than that of mechanical commutator, the cost and selling price of DC brushless motor are increased. The price of DC brushless motor is the main factor limiting its application to civil products. In view of the increasing demand for low-cost DC brushless motor in the automotive industry, home appliance industry and office automation field at home and abroad, the purpose of the new DC brushless motor developed is to provide a DC brushless motor with simple structure, easy fabrication, reliable performance, convenient control and low cost, so as to apply to industrial control, especially in the field of various civil products.

3. In the design of DC brushless motor, in the past, most DC brushless motors used integer slot design. In recent years, fractional slot technology is increasingly used in brushless DC motor.

Some advantages of fractional slot technology for DC brushless motor:

(1) For the multi pole brushless DC motor, fewer stator slots can be used, which is conducive to improving the slot full rate and thus improving the performance of the brushless DC motor; At the same time, a small number of components can simplify the wiring process and wiring, which is helpful to reduce costs.

(2) Increase the short (long) distance and distribution effect of the winding, and improve the sine of the back EMF waveform.

In short, the application of fractional slot technology is conducive to energy saving, material saving, miniaturization, lightweight, labor saving and production automation of DC brushless motor, thus reducing product cost and increasing product competitiveness.