Sensored Motors

Sensored motors use devices like Hall effect sensors to monitor the rotor’s position in real time. These sensors send continuous feedback to the motor driver, which allows precise control over the timing and phase of the motor’s power. In this setup, the driver relies heavily on the information from the sensors to adjust current delivery, ensuring smooth operation, especially during low-speed or start-stop conditions. This makes sensored motors ideal for applications where precise control is crucial, such as robotics, electric vehicles, and CNC machines.

Because the motor driver in a sensored system receives exact data about the rotor's position, it can adjust the motor’s operation in real-time, offering greater control over speed and torque. This advantage is particularly noticeable at low speeds, where the motor must operate smoothly without stalling. In these conditions, sensored motors excel because the driver can continuously correct the motor's performance based on the sensor feedback.

However, this close integration of the sensors and the motor driver increases system complexity and cost. Sensored motors require additional wiring and components, which not only raise the expense but also increase the risk of failures, especially in harsh environments. Dust, moisture, or extreme temperatures can degrade the performance of the sensors, which may lead to inaccurate feedback and potentially disrupt the driver’s ability to control the motor effectively.

Sensorless Motors
Sensorless motors, on the other hand, do not rely on physical sensors to detect the rotor’s position. Instead, they use back electromotive force (EMF) generated as the motor spins to estimate the rotor's position. The motor driver in this system is responsible for detecting and interpreting the back EMF signal, which becomes stronger as the motor increases in speed. This method simplifies the system by eliminating the need for physical sensors and extra wiring, reducing cost and improving durability in demanding environments.

In sensorless systems, the motor driver plays an even more critical role since it must estimate the rotor's position without the direct feedback provided by sensors. As speed increases, the driver can accurately control the motor by using the stronger back EMF signals. Sensorless motors often perform exceptionally well at higher speeds, making them a popular choice in applications like fans, power tools, and other high-speed systems where precision at low speeds is less critical.

The drawback of sensorless motors is their poor performance at low speeds. The motor driver struggles to estimate the rotor's position when the back EMF signal is weak, leading to instability, oscillations, or trouble starting the motor. In applications requiring smooth low-speed performance, this limitation can be a significant issue, which is why sensorless motors are not used in systems that demand precise control at all speeds.