Introduction and Working Principle of Brushless DC Motor

I. What is a Brushless DC Motor  

A brushless DC motor consists of a main motor body and a driver. It is a typical example of an integrated mechanical and electrical product. Since brushless DC motors operate in a self-controlled manner, they do not require additional starting windings on the rotor, unlike synchronous motors under variable-frequency speed control during heavy-load startups. Moreover, brushless DC motors do not experience oscillations or loss of synchronization when subjected to sudden load changes.  

For small and medium-capacity brushless DC motors, the permanent magnets are now often made from high magnetic energy product materials such as rare-earth neodymium-iron-boron (Nd-Fe-B). As a result, the size of rare-earth permanent magnet brushless DC motors is reduced by one frame size compared to three-phase asynchronous motors of the same capacity.  

II. Working Principle of Brushless DC Motors  

Brushless DC motors use semiconductor switching devices to achieve electronic commutation, meaning that electronic switching devices replace traditional contact-type commutators and brushes. Brushless DC motors offer advantages such as high reliability, no commutation sparks, and low mechanical noise. They are widely used in high-end tape decks, video recorders, electronic instruments, and automated office equipment.