Brushless dc motor of motor controller itself is electromechanical energy conversion part, it besides the armature, permanent magnet motor controller excitation two points, also with sensors. Motor controller itself is the core of the brushless dc motor controller, it is not only related to the performance index, noise, vibration, reliability and service life, etc. , involving the manufacturing costs and product cost. Because use permanent magnet magnetic field, make the brushless dc motor controller get rid of the traditional design of general dc motor controller and structure, meet the requirements of various applications market, and development in the direction of the province copper material saving, simple and convenient manufacturing. Is closely related to the development of permanent magnetic field and permanent magnet materials, the application of the third generation of permanent magnetic material, make brushless dc motor controller to efficiency, miniaturization, energy-saving direction. In order to achieve the electronic commutation must have a position signal to control the circuit. Early with the mechanical and electrical position sensor position signal, has been gradually use electronic position sensor or other ways to get position signal, the easiest way is to use the armature winding voltage signals as position. To realize the control of motor speed controller must have a speed signal. With similar position signal obtained speed signal, the simplest speed sensor is measuring frequency type tachogenerator controller combined with electronic circuits. Commutation of the brushless dc motor controller consists of two parts, drive and control circuits, it is not easy to separate the two parts, especially small power circuit will be integrated into a single both usually application-specific integrated circuit. In the power of the larger motor controller, drive circuit and control circuit can become one. Drive circuit output power, drive motor armature winding, and controlled by the control circuit. The driver circuit has from the linear amplification state into PWM switch state, the corresponding circuit composition also from transistor discrete circuit into modular integrated circuit. Modular integrated circuit with power bipolar transistors, power field effect tube and isolation gate field effect in the form of a bipolar transistor, etc. Control circuit is used as the control motor speed, steering, current controller (Or torque)And protect the motor controller of over-current, over-voltage, overheating, etc. The above parameters easily converted to analog signals, use this to control is relatively simple, but from the point of development, the parameters of the motor controller should be converted to digital quantity, through the digital control circuit to control the motor controller. At present, the control circuit has a special integrated circuit, microprocessor and digital signal processor of three kinds of ways. Using digital signal processor of control circuit is the future development direction.
