Motors are frequently encountered in our daily lives, but I am not very familiar with the various types of motors and their characteristics. Therefore, I gathered a lot of information to summarize them for easier future reference.
Motors are mainly divided into DC Motors and AC Motors, along with special motors based on unique principles. They differ significantly in terms of power supply methods, structures, and applicable scenarios.
1. DC Motors (Direct Current Motors)
DC motors require a direct current power supply to operate, with the core feature being excellent speed regulation performance, allowing for smooth and precise speed control.
The main classifications and characteristics are as follows:
- Permanent Magnet DC Motor: Uses permanent magnets to create the stator magnetic field, featuring a simple structure, small size, and high efficiency. The downside is that the permanent magnets are easily affected by temperature, commonly used in low-power applications such as toys and small household appliances.
- Electromagnetic DC Motor: Generates a magnetic field through current in the stator windings, with a wider power range suitable for industrial equipment. However, it has a more complex structure and requires regular maintenance of the excitation windings.
- Brushless DC Motor (BLDC): Eliminates traditional brushes and commutators, using electronic components for commutation. It has advantages such as long lifespan, low noise, and low failure rate, widely used in drones, new energy vehicles, and home appliances.
2. AC Motors (Alternating Current Motors)
AC motors connect to an alternating current power supply, featuring a relatively simple structure, low cost, and high reliability, making them the mainstream motor type in industrial and civilian fields.
The main classifications and characteristics are as follows:
- Asynchronous Motor (Induction Motor): The rotor speed is always lower than the stator rotating magnetic field speed, with the simplest structure, lowest cost, and minimal maintenance. The downside is the difficulty in speed regulation, commonly used in applications like pumps, fans, and machine tools where speed regulation is not critical, accounting for over 80% of all motor applications.
- Synchronous Motor: The rotor speed matches the stator rotating magnetic field speed exactly, with adjustable power factor (which can improve grid power factor) and stable operation. The downside is the difficulty in starting, commonly used in large generators, precision machine tools, and elevators.
3. Special Motors
Special motors are designed based on unique principles to meet specific functional requirements rather than just power output.
Common types and characteristics are as follows:
- Stepper Motor: Converts electrical pulse signals into precise angular or linear displacement, moving step by step with high positioning accuracy. The downside is that it tends to vibrate at low speeds, commonly used in printers, 3D printers, and CNC machine tools that require precise positioning.
- Servo Motor: Combines a motor, sensor, and controller to provide real-time feedback on position and speed, achieving extremely high precision in closed-loop control. It has fast response speed and strong overload capacity, making it a core component in robotics and automated production lines.
- Torque Motor: Can operate for long periods at low speeds or even in stalled conditions, providing high torque without the need for a reduction mechanism. It is commonly used in winding machines and valve control applications that require low-speed high torque.
In the future, I will gradually discuss some motor control technologies, such as FOC, PWM, six-step commutation, PID, speed loop, current loop, position loop, torque loop, SVPWM, MPC, SMC, and coordinate transformations (PARK, CLARK), etc.