In the field of motor control, sensored motors are widely used in electric vehicles, robots, CNC equipment, and other applications requiring precise motion control due to their excellent accuracy and stability. Unlike sensorless motors, sensored motors are equipped with internal position sensors that provide real-time rotor position feedback, giving them significant advantages during low-speed operation and startup. But how exactly do sensored motors achieve smooth low-speed startup and stable running?
Role of Sensors: Accurate Rotor Position Detection
Sensored motors typically use Hall sensors or encoders to detect rotor position and speed. The motor controller reads these signals to accurately determine the rotor angle, enabling optimal alignment between the current and the rotor’s magnetic field.
At low speeds, the back electromotive force (EMF) signal is weak, making it difficult to estimate rotor position without sensors.
The sensors provide precise real-time data, allowing the motor to maintain smooth, jitter-free operation even at startup or low speeds.
Low-Speed Startup: Precise Phase Alignment
During motor startup, synchronizing current with the rotor magnetic field is critical for smooth operation.
Sensored motors leverage sensor feedback to allow the controller to calculate the proper energizing sequence in advance.
Compared to sensorless motors, which rely on back EMF and can experience “blind zone” startup issues, sensored motors achieve accurate phase alignment immediately upon startup, avoiding jitter, stalling, or reverse rotation.
As a result, sensored motors can start reliably even under high-load conditions.
Low-Speed Stability: Real-Time Closed-Loop Control
During low-speed operation, sensored motors maintain stability through closed-loop control.
The controller continuously compares the setpoint with the actual feedback and dynamically adjusts current and voltage.
This closed-loop regulation ensures consistent speed and prevents fluctuations caused by load changes or external disturbances.
This feature is particularly valuable for precision equipment and robotic joints, where speed stability is critical.
Efficiency and Protection
In addition to low-speed performance, sensored motors offer improved efficiency and protection.
Accurate rotor position detection allows the motor to energize at the optimal phase, reducing power loss and improving overall efficiency.
During abnormal conditions such as stalling or overload, sensor feedback enables the controller to cut off or adjust current, protecting the motor from damage.
Application Advantages
Sensored motors excel in applications requiring frequent low-speed startups and precise control:
Electric Vehicles: Ensures smooth and vibration-free startup and low-speed driving.
Industrial Robots: Provides smooth joint movement and high operational precision.
CNC Machines: Maintains stable spindle speed during low-speed cutting for high-quality machining.
Household Appliances: For devices like air conditioner compressors, offering reliable startup and long-term stable operation.
Conclusion
Sensored motors achieve low-speed startup and stable operation through built-in sensors that provide real-time rotor position feedback, ensuring precise synchronization between current and magnetic field. Their accurate startup, smooth running, closed-loop control, and high-efficiency protection make them ideal for electric vehicles, robotics, and precision manufacturing. In short, the key advantage of sensored motors lies in their reliability during low-speed and startup conditions, making them increasingly favored in high-end applications.