1.Permanent Magnet DC Motor

For those of you who are engineers, have you ever thought of replacing the old excitation DC motor with a more efficient, lighter and simpler motor? Yes, I am talking about the permanent magnet DC motor! Compared to the old motor, the permanent magnet DC motor eliminates the complex excitation winding and pole core, and instead uses permanent magnet poles to generate the magnetic field. Such a motor is not only similar to the characteristics of his excitation DC motor, but also has a simple structure, reliable operation, high efficiency, small size, light weight and other characteristics. It is the meat and potatoes in the minds of engineers!

2. Asynchronous starting permanent magnet synchronous motor

Asynchronous starting permanent magnet synchronous motor! This guy is not only a permanent magnet synchronous motor, but also has the characteristics of the induction motor and electro-excitation synchronous motor, you can start it yourself! You may ask, how is this realized? In fact, it is very simple, it uses the asynchronous torque generated by the interaction between the stator rotating magnetic field and the cage rotor to realize the starting. When it is running normally, the rotor speed and rotating magnetic field synchronization, the cage rotor will no longer play a role. 

This guy is really great, not only good for starting, but also high efficiency when running, the working principle and the electro-excited synchronous motor is basically the same. I must say, the wisdom of engineers is really endless!

With induction motor is very different! It has a constant speed, high power factor, or even super power factor, which not only reduces the resistance loss, but also effectively reduces the fan friction and copper consumption loss, and improves the efficiency. What's more, it has a wide economic operating range, capable of maintaining high efficiency and high power factor both at rated load and at light loads. In addition, permanent magnet motors are much smaller and heavier than induction motors, yet they have a minimal impact on the power grid. Of course, it has its drawbacks, such as higher price and irreversible demagnetization, but this does not overshadow its many advantages.

3. Permanent magnet brushless DC motor

Permanent magnet brushless DC motor, by electronic commutation device to realize the replacement of brush commutator, retaining the excellent characteristics of DC motor. Its structure is simple, reliable, easy to maintain, and at the same time, it has the characteristics of DC motor with large starting torque and good speed regulation performance. 

Compared with the traditional DC motor, the reliability is greatly improved by eliminating the brush commutator; at the same time, the loss is mainly generated by the stator, the heat dissipation conditions are optimized, and the volume and weight are greatly reduced. Thus, the permanent magnet brushless DC motor can be said to be a combination of AC and DC motors, realizing the “advantages of one” of the perfect realm.

4. Speed-regulated permanent magnet synchronous motor

Let's talk about speed permanent magnet synchronous motor and permanent magnet brushless DC motor. These two guys look basically the same, there are multiphase windings on the stator and permanent magnets on the rotor, and the advantages are similar. But what is the difference between them? It really lies in the fact that permanent magnet brushless DC motors are able to synchronize based on rotor position information, while speed-regulated permanent magnet synchronous motors require a set of electronic control systems in order to synchronize and speed-regulate. 

Well, it looks like this electronic control system is a bit powerful. However, there are a lot of benefits, after all, the abolition of the commutator, reliability has greatly improved; and stator loss is mainly heat dissipation problems, unlike other motors so annoying; most importantly, its size and weight are very small, simply a “small and exquisite” guy.

5. Permanent magnet synchronous generator

Permanent magnet synchronous generator! It is a unique structure of the generator, unlike other synchronous generators, it uses permanent magnets to establish a magnetic field, completely eliminating the need for excitation windings, excitation power supply, collector rings and brushes and other components, is simply too convenient! 

Not only that, permanent magnet synchronous generators can operate stably and efficiently without much maintenance. If rare-earth permanent magnet material is used, not only the air gap magnetic density is high, the power density is also high, the volume is small, the quality is light, which perfectly meets the modern demand for compactness and efficiency. However, since it uses permanent magnets to establish a magnetic field, it is difficult to regulate the output voltage and reactive power by adjusting the excitation. 

In addition, permanent magnet synchronous generators usually use neodymium-iron-boron or ferrite permanent magnets, which have high temperature coefficients, and the output voltage varies with the ambient temperature, which can cause the output voltage to deviate from the rated voltage.