Working principle and characteristics of earth permanent magnet motor

We introduced the principle of high-efficiency and energy-saving motors last time, and we can understand that the principle of this motor is a bit complicated. So for another type of motor: the earth permanent magnet motor, what is its working principle? And what are its advantages? Let’s take a look below!

The earth permanent magnet motor is a new type of permanent magnet motor that appeared in the early 1970s. Because of the high magnetic energy product and high coercivity of the earth permanent magnet (especially the high intrinsic coercivity), the earth permanent magnet motor has small size, It has a series of advantages such as light weight, high efficiency and good characteristics.

The advantages are as follows:

Due to the magnetic properties of earth permanent magnet materials, it can establish a strong magnetic field without the need for external energy after magnetization. The earth permanent magnet motor made by replacing the electric excitation field of a traditional motor not only has high efficiency, but also has a beautiful structure. It is simple, reliable in operation, and can also meet the requirements of small size and light weight.

This motor can not only achieve high performance that traditional electric excitation motors cannot match (such as ultra-high efficiency, ultra-high speed, ultra-high response speed), but also can be made into special motors that can meet specific operating requirements, such as elevator traction motors, automotive special motors, etc. Motors, etc.

The combination of earth permanent magnet motors with power electronics technology and microcomputer control technology has improved the performance of the motor and transmission system to a new level. Then improving the functions and levels of supporting skills and equipment is an important development direction for the electrical industry to adjust the industrial structure.

Rare earth permanent magnet motors are widely used in al all fields of aviation, aerospace, national defense, equipment manufacturing, industrial and agricultural production, and daily life. It includes permanent magnet synchronous motors, permanent magnet generators, DC motors, brushless DC motors, AC permanent magnet servo motors, permanent magnet linear motors, special permanent magnet motors and related control systems, covering al the entire motor industry.

Here’s how it works:

The operating principle of the earth permanent magnet motor is the same as that of the electrically excited synchronous motor. The difference is that the former uses permanent magnets instead of field windings for excitation. When the three-phase stator winding of the permanent magnet motor (each with a phase difference of 120°) is supplied with a three-phase alternating current with a frequency of f, a rotating magnetic field that moves at a synchronous speed will be generated. In a steady state, the main pole magnetic field rotates synchronously with the rotating magnetic field, so the rotor speed is also synchronous speed. The stator rotating magnetic field is always in relative motion with the main pole magnetic field established by the permanent magnet. They interact with each other and generate electromagnetic torque. , drives the motor to rotate and converts energy.