Brushless dc electric machine to their excellent properties has been widely used in the field of drive control, but due to mechanical switch and common dc motor brush, poor reliability, need regular maintenance; Produce electromagnetic interference in phase noise big, affect the further application of the dc motor in the control system. Mechanical commutation bring in order to overcome the shortcomings, in electronic commutation replace the mechanical commutation of brushless dc motor arises at the historic moment. Harrison and others for the first time applied to replace the mechanical brush commutation circuit with transistor patents, marks the birth of modern brushless dc motor. For electronic commutation of brushless dc motor really into the practical phase, in 1978 the classical MAC brushless dc motor and the drive to launch. After the international brushless motor has carried on the thorough research, successively developed ChengFangBo brushless motor brushless dc motor and the sine wave.
in structure, with a brush dc motor, brushless dc motor stator winding as the armature, replaced by permanent magnet excitation winding. According to the inflow of the armature winding current waveform, brushless dc motor can be divided into the square wave brushless dc motor (BLDCM)Dc motor and the sine wave,永磁同步电动机), BLDCM electronic commutation to replace the original dc motor mechanical commutation, done by permanent magnet rotor, eliminating the brush; All-digital fuzzy is replacing field winding of synchronous motor rotor with permanent magnet, eliminating the field winding, slip ring and brush. In the same condition, the driving circuit for square wave more easily, and easy to control, thus the application of BLDCM is all-digital fuzzy to the more widely.
brushless dc motor by electronic commutation circuit commonly, the rotor position detection circuit and motor ontology of three parts, electronic commutation circuit generally consists of control part and driving part, and the detecting of rotor position is used commonly position sensor to complete. Work, the controller according to the position of motor rotor position sensor and orderly trigger driver circuit of each power tube, and an orderly in flow, to drive the dc motor.
as the permanent magnet new material, microelectronics technology, automatic control technology and power electronic technology especially high power switching device development, brushless motor got rapid progress. Brushless dc motor is not specifically to the electronic commutation of dc motor, but refers to a brush dc motor external characteristic of the electronic commutation motor. Brushless dc motor not only keep the good dynamic and static traditional dc motor speed control features, and simple structure, reliable operation, easy to control. Its application from the initial military industry, medical, information, aerospace, household appliances as well as the rapid development of industrial automation field.
