What Are Sensored Brushless Motors?

In today's rapidly evolving motor technology, sensored brushless motors are increasingly becoming the core power components of many high-precision and high-performance devices due to their unique technical advantages.

A sensored brushless motor, fully termed as "brushless motor with position sensors," is a type of motor that incorporates additional position sensing elements such as Hall sensors or encoders on top of traditional brushless motor designs. While brushless motors themselves eliminate friction losses by using electronic commutation instead of mechanical brushes, the "sensored" feature enables the motor to precisely detect the rotor's real-time position, allowing for smarter and more efficient operation control.

The operation of a sensored brushless motor relies on the close cooperation between sensors and the electronic commutation system. Taking Hall sensors as an example, they are installed on the stator of the motor to detect the position information of the rotor's permanent magnets in real-time and send signals back to the motor driver. The driver then precisely controls the direction and magnitude of the current in the stator windings based on these received signals, ensuring that the rotor rotates steadily in the intended direction and at the desired speed. This "sense-feedback-control" closed-loop system significantly improves control accuracy and stability compared to sensorless brushless motors, which estimate rotor position solely based on back EMF.

Because it can obtain the rotor position in real-time, sensored brushless motors excel in speed regulation and positioning. For instance, in industrial robot joint drives, they can achieve precise positioning down to ±0.01mm, meeting the demands of precision operations.

Even at low speeds, sensored brushless motors maintain smooth operation, avoiding issues like jittering and loss of steps. In 3D printers, for example, using sensored brushless motors for filament feeding ensures stable material delivery at very low speeds, thereby maintaining print quality.

When there is a sudden change in load, sensored brushless motors can adjust speed and torque within milliseconds. In scenarios such as rapid directional changes in drones or instantaneous acceleration in power tools, they can quickly respond to control commands, enhancing device performance.

Precise current control reduces energy losses, allowing sensored brushless motors to operate efficiently across the entire speed range. Compared to sensorless solutions, this can improve energy efficiency by 10%-15%.