In modern automation, robotics, and smart manufacturing, sensored motors are widely used due to their high precision and stability. Compared to sensorless motors, sensored motors can detect the rotor position in real time, enabling precise control of speed and torque. To understand why these motors operate so “stable, accurate, and fast,” it is essential to grasp their speed control principles and core technologies.
Basic Structure and Working Principle of Sensored Motors
Sensored motors typically refer to brushless DC motors (BLDC) or permanent magnet synchronous motors (PMSM) equipped with position sensors. Inside the motor, Hall sensors, resolvers, or encoders are installed to detect rotor position and speed in real time. These sensor signals are fed to the motor controller, which adjusts the current phase to achieve precise field-oriented control.
In short, the core of sensored motor control is a closed-loop feedback system. The sensors continuously monitor rotor movement, and the controller calculates and adjusts in real time to ensure the motor runs at the set speed, achieving high efficiency and low error operation.
Three Core Elements of Speed Control
1.Speed Detection
Hall sensors are the most common detection method. When a rotor magnet passes the Hall element, it generates a pulse signal. By counting the number of pulses over time, the controller calculates the actual rotor speed. For higher precision, encoders can be used, offering angular resolution down to 0.1°, suitable for fine control.
2.Signal Feedback and Error Calculation
The control system compares the actual speed with the target speed to generate an error signal . This signal enters a control algorithm, typically a PID controller, which calculates adjustments based on proportional (P), integral (I), and derivative (D) terms to regulate the motor’s current or voltage dynamically.
3.Current and Voltage Modulation
Based on the PID output, the controller adjusts the PWM (Pulse Width Modulation) signals to change the magnitude and direction of the stator current, controlling torque and speed dynamically. For PMSMs, vector control (FOC) is applied to maintain the rotor magnetic field alignment, improving efficiency and response speed.
Advantages of Sensored Motor Speed Control
High Precision: Real-time rotor angle feedback allows extremely low error.
Excellent Start Performance: Unlike sensorless motors, sensored motors can start from zero speed without jitter or step loss.
Strong Dynamic Stability: The closed-loop system quickly corrects speed deviations caused by external disturbances.
Support for Advanced Control Algorithms: Compatible with FOC, vector control, and direct torque control (DTC), meeting the demands of high-performance applications.
Applications and Trends
Sensored motors are widely used in industrial robots, drones, automated production lines, electric vehicles, and medical devices. With improvements in sensor accuracy and control algorithms, future sensored motors will achieve lower latency, faster response, and stronger adaptive control. The integration of AI and digital signal processing is also driving the development of “intelligent sensored motors,” which can automatically adjust parameters according to load conditions, achieving true smart drive capabilities.
Conclusion
In summary, the speed control of sensored motors relies on sensor feedback and closed-loop regulation. Through precise speed detection, error calculation, and current control, these motors operate stably and efficiently. Representing a high level of motor control technology, sensored motors provide robust support for smart manufacturing. As automation and new energy industries advance, sensored motor control technology will continue to innovate, becoming a core component of high-performance motion control systems.