the industry application of brushless dc motor brushless dc motor is nowadays the most popular one of words, every day there are more than thousands of people in the search to understand this word, it is because of the brushless dc motor has both ac motor has simple structure, reliable operation, easy maintenance and a series of advantages, and dc motor running with high efficiency, no excitation loss and speed control performance is good, so in the areas of current popular industry began to gradually becomes widespread, such as production lines, medical equipment, automated production, textile industry, packaging machinery, and robots, and so on. The application of brushless dc motor are divided into the following three categories: 1, need constant speed operation of mechanical general industry does not need speed, mostly adopt ac asynchronous or synchronous motor as a power source. With the continuous development of brushless dc motor technology mature, the power is not more than 2 kw and continuously under the condition of constant speed operation, in order to reduce the volume, improve efficiency, reduce energy consumption, energy conservation and emissions reduction, more and more enterprises choose to brushless dc motor as power source, the application of this kind of brushless dc motor are: automatic doors, elevators, water pump, fan, etc. And in need of large power machinery, in addition to the permanent magnet motor drives, and should be added to the external control equipment, the cost is out of step input and return, so less application current brushless motors. 2, need speed running the application of this type mechanical equipment include any speed setting and adjustment, the control accuracy is not high. This kind of system can be divided into two kinds: one kind is open loop speed control system, the other is a closed-loop speed control system (This time the speed of feedback device with low resolution or ac, dc pulse encoder speed, etc. )。 There are three kinds of commonly used motor mainly: brushless dc motor, asynchronous motor and brushless dc motor. In the packaging machinery, food machinery, printing machinery, conveying machinery, textile machinery and transport vehicles can be seen everywhere. Adjustable speed system application domain with the more is the dc motor at the beginning, with the development of ac speed regulating technique especially the inverter and controller, ac frequency conversion technology obtained the widespread application, frequency converter and ac motor to infiltrate the original application field of the vast majority of dc speed regulating system. In recent years, because of the brushless dc motor the advantages of small volume, light weight and high efficiency and energy saving of the increasingly prominent, small and medium-sized power ac frequency conversion system is gradually replaced by the brushless dc motor speed control system, especially in textile machinery, printing machinery, such as the original field frequency conversion system is widely applied. In some application fields directly by the battery power supply, now more use of brushless dc motor. 3, need precise control of mechanical servo motor in high precision in the field of industrial automation control, has always been one of the most important motor applications, the control of the servo motor performance requirements are also different, in the actual application, servo motor control in different forms: torque/current control, speed control and position control. Due to the good control performance, brushless dc motor (BLDCM) in high speed, high precision positioning system gradually replace the dc motor and stepper motor, become one of the modern choice of motor servo system. At present, scanner, camera, CD cd-rom drives, medical diagnostic CT, computer hard disk drives, and numerical control lathe driving medium have started using brushless dc motor.
