What Are The Differences Between Servo Motor And Brushless Dc Motor

Servo motors and brushless DC motors are two common types of motors used in industry, and they have their own characteristics for achieving precise control. Servo motors and brushless motors are both very important parts of industrial automation and robotics applications, so an in-depth understanding of the differences between these two types of motors is key to creating efficient processes. In the following article, we will introduce the differences between servo motors and brushless DC motors.

 

Structure Difference

The servo motor includes a motor, an encoder, and a controller. The encoder gives a feedback signal, and the controller receives the feedback signal and controls the motor speed, direction, and position. The controller can be directly programmed for better and more accurate control of the motor.

A brushless DC motor, on the other hand, consists of only a brushless motor and a controller. The controller receives input signals and controls the motor to rotate, stop, and reverse.

Therefore, the servo motor has a more complete closed-loop control capability and can be positioned more accurately.

 

Working Principle Difference

The working principle of brushless DC motors is the same as that of traditional DC motors, which use the principle of DC magnetic field interaction to achieve motor operation. However, unlike traditional DC motors, brushless DC motors use permanent magnets as the rotor and use electronic controllers to change the direction of the magnetic field on the rotor, thereby controlling the speed and direction of the motor.

 

Servo motors, on the other hand, work by accepting electrical pulse signals from an external controller to change the position and speed of the motor. The controller will transmit the electrical pulse signals to the motor to control the rotor of the motor to rotate a certain angle, in order to accurately control the output angle of the motor within a given range.

 

Control methods difference

Servo motors and brushless DC motors are both very easy to control, but servo motors can better control the position and speed of the motor. Because the servo motor has a feedback mechanism, the position and speed of the motor can be adjusted in a very short time to achieve more precise control. Servo motors can achieve high speed, high acceleration, and high precision movement during the working process.

 

In contrast, DC brushless motors with open-loop control can achieve speed and direction control by directly varying the supply voltage and current, or they can use electronic controllers to regulate the speed of the motor, which may result in less precise position control than servo motors. Although feedback control can be carried out, the accuracy and control ability is limited to closed-loop control.

 

switching frequencies difference

We usually use high-frequency switching from 30kHz to 50kHz for the servo motor controller, so that the output of the motor can be changed quickly and smoothly. Brushless motors, due to their lower control accuracy, generally have a switching frequency of no more than 20kHz, which also has a certain impact on the stability of the motor's operation.

 

Performance characteristics Difference

The advantages of brushless DC motors are fast startup, high speed, high precision, high efficiency, low noise, simple maintenance, long life, and other characteristics, so they are widely used in various fields. However, the positioning accuracy and speed control of a brushless DC motor are slightly inferior to the servo motor.

 

Servo motors, on the other hand, are characterized by high precision, wide speed range, good stability, etc., and are suitable for applications requiring high control precision. However, the price of servo motors is higher, and the need for specialized controllers increases the cost.

 

Application Difference

A Brushless DC motor is suitable for high-speed rotation, torque control, and precision requirements of relatively low occasions. Such as bicycles, power tools, household appliances, and so on.

 

The Servo motor is suitable for applications requiring high precision, high speed, and high control accuracy, such as CNC machine tools, clothing machinery, printing equipment, mold processing, aircraft, spacecraft, and so on.

 

Through the comparative analysis of servo motors and brushless motors, we can clearly understand the differences between these two types of motors. Servo motors are good at precise control and are particularly suitable for applications that require high precision motion control. Brushless motors are compact and efficient and can take on many small applications such as home appliances and consumer electronics. When in need of a motor control solution, it is important to understand the characteristics of these two types of motors and make a choice based on your needs.