A brushless DC motor with a general DC motor having the same working principle and application characteristics, and its composition is not the same. In addition to the motor itself, the former more than a change to the circuit, the motor itself and commutation circuit close together. Many small power motors, motor commutation circuit synthesis integrated brushless DC motor and DC motor is exactly the same in appearance.
In order to realize the electronic commutation must have a position signal to the control circuit. Early electromechanical position sensor position signals, and has been gradually replaced with electronic position sensors or other method to obtain the position signal, the most convenient method is the use of the armature winding of the electric potential signal as the position signal
Brushless DC motor, the motor itself is part electromechanical energy conversion, motor armature, permanent magnet excitation two components, but also with the sensor. Motor is a brushless DC motor core, it is not only related to performance indicators, noise, vibration, reliability and service life, but also the manufacturing cost and product cost. As a result of the permanent magnet magnetic field, the brushless DC motor to get rid of the traditional design and structure of the general DC motor to meet the requirements of various applications market and development toward the direction of the Province, copper and materials, manufacture and easy. Permanent magnetic field is closely related to the development and application of the permanent magnet material, the application of the third generation of the permanent magnet material, prompting the brushless DC motor to the high efficiency, miniaturization, saving direction forward.
To achieve motor speed control speed signal. Similar way to guide to the position signal to obtain a speed signal, the easiest speed sensor is a tachogenerator frequemeasurement is combined with electronic circuits.
The brushless DC motor of the commutation circuit by the drive and control of two-part composition, the two parts are not easy to separate, especially small-power circuit is often both integrated into a single ASIC.
The motor speed control circuit used as a control, steering, current (or torque), as well as protect the motor overcurrent, overvoltage, overheating. The above parameters easily converted into an analog signal, using this relatively simple to control, but the development point of view, the parameters of the motor should be converted into a digital number, by digital control circuit to control the motor. At present, the control circuit has a mode of the three components of the ASIC, the microprocessor and digital signal processor. In less demanding situations on the motor control ASIC control circuit is simple and practical way. The digital signal processor control circuit is the future direction of development