So: Yes, it’s the same thing. If you look at the motor side, both variants have the same design: permanent magnets in the rotor and a corresponding stator winding – distributed winding, tooth winding, etc. So where do the two terms actually come from? 🤔
BLDC is used more commonly for simpler motors, originally as a replacement for brush motors. A simpler, often integrated 4-quadrant controller or simple regulator is usually suitable for BLDC. Feedback is usually provided via Hall sensors.
Servo motors come from the “more complex” positioning task. They are controlled by servo controllers with corresponding, e.g., optical encoder systems and sine commutation.
That was the starting position. Today, the two terms are used quite interchangeably. There are sensorless servo motors and BLDC motors with encoders. Ultimately, they are always the same. Logically, everything has to fit together. So motor + encoder system + controller.
In short: BLDC = servo motor.
Incidentally, a small side note: it would be more correct to refer to an electronically commutated electric motor rather than a BLDC motor.
This is because the BLDC motor has no electromagnetic relationship to a DC motor. But I think the train for renaming it has already left the station… 😅
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