Method and circuitry to generate speed information in a control circuit of a brushless DC motor to control it by means of a digital control device

摘要

The invention relates to a speed control system, method and circuit for performing the method for a brushless DC motor using a digital servo loop, namely an economical and a simple means for generating information regarding the speed with precision and easily convertible digital words by can be processed by a microprocessor or by wired assemblies of normal digital circuits such as counters, gates, adders and subtractors, flip-flops, multipliers, memories etc. The motor has a permanent magnet rotor. The voltage on at least one of the stator windings is used to generate speed information. From this, a threshold value detector is converted into a square wave, which is further processed by the circuit.