Brushless dc motor controller in general is divided into a commutator of the dc motor and the dc motor commutator two kinds big. Dc motor protection function in the layout, the price, both as exchange of motor, but for a long time the exchange of motor speed control performance failed to get satisfied, with is a dc motor with its good control characteristics obtained widespread use. Today, is the exchange of motor speed control performance has to deal with, but because of the equipment and commensurate reforms necessary to a long process. Haven't throughout exchange motor drive restraint, dc motor system is still in common use. Dc motor speed control system adopt constant dc voltage to the dc motor power supply, through the process of transition resistance of the armature circuit to accomplish speed regulation. This kind of way to a brief and easy, convenient equipment manufacturing, the price is low; But the problem is the low effectiveness, the machine features soft, means less than gain wider war slide speed regulating function. The law is only applicable in small power and speed adjustment scale request is not big. Of this kind of control method can obtain a wider war sliding speed smaller scale, the speed change rate of speed regulating function. But this method system are the important problem of big weight, covers an area of more than, for low and hard. In recent years, with rapid growth of the power electronic technique, by the thyristor inverter power supply of the dc motor speed control system has to replace the generator controller a motor drive system, its control function are also far more than the generator controller, motor drive system. Especially the rapid growth of large scale integrated circuit technique and computer technique, make the precision of the dc motor speed control system, the static function, reliability, have greater progress. Power electronics technique and the growth of high power devices IGBT is instead of thyristor, presents a function better dc speed regulating system.
