QINGDAO ENNENG MOTOR CO.,LTD.
QINGDAO ENNENG MOTOR CO.,LTD.
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ENNENG High-Efficiency Ultra Low-Speed Interior Permanent Magnet Motor
What is the permanent magnet motor?
Permanent Magnet Synchronous Motor (PMSM) is brushless and has very high reliability and efficiency. Due to its permanent magnet rotor, it also has a high torque with a small frame size and no rotor current. Instead of using winding for the rotor, permanent magnets are mounted to create a rotating magnetic field. As there is no supply of DC source, these types of motors are very simple and less cost. The permanent magnet synchronous motors are AC synchronous motor whose field excitation is provided by permanent magnets and that has a sinusoidal back EMF waveform. The permanent magnets enable the PMSM to generate torque at zero speed. This motor delivers high-efficiency operations and requires a digitally controlled inverter.
Analysis of the principle of the technical advantages of permanent magnet motor
The principle of a permanent magnet synchronous motor is as follows: In the motor's stator winding into the three-phase current, after the pass-in current, it will form a rotating magnetic field for the motor's stator winding. Because the rotor is installed with the permanent magnet, the permanent magnet's magnetic pole is fixed, according to the principle of magnetic poles of the same phase attracting different repulsion, the rotating magnetic field generated in the stator will drive the rotor to rotate, The rotation speed of the rotor is equal to the speed of the rotating pole produced in the stator.
Advantages Of Rare-earth Permanent Magnet Motors:
High efficiency: The efficiency curve of the asynchronous motor generally falls faster under 60% of the rated load, and the efficiency is very low at light load. The efficiency curve of the rare earth permanent magnet motor is high and flat, and it is in the high efficiency area at 20%~120% of the rated load.
High power factor: The measured value of the power factor of the rare earth permanent magnet synchronous motor is close to the limit value of 1.0. The power factor curve is as high and flat as the efficiency curve. The power factor is high. Low-voltage reactive power compensation is not required and the power distribution system capacity is fully utilized.
Stator current is small: The rotor has no excitation current, the reactive power is reduced, and the stator current is significantly reduced. Compared with the asynchronous motor of the same capacity, the stator current value can be reduced by 30% to 50%. At the same time, because the stator current is greatly reduced, the motor temperature rise is reduced, and the bearing grease and bearing life are extended.
High out-of-step torque and pull-in torque: Rare earth permanent magnet synchronous motors have higher out-of-step torque and pull-in torque, which makes the motor have higher load capacity and can be smoothly pulled into synchronization.
Flux weakening/intensifying of PM motors
Flux in a permanent magnet motor is generated by the magnets. The flux field follows a certain path, which can be boosted or opposed. Boosting or intensifying the flux field will allow the motor to temporarily increase torque production. Opposing the flux field will negate the existing magnet field of the motor. The reduced magnet field will limit torque production, but reduce the back-emf voltage. The reduced back-emf voltage frees up the voltage to push the motor to operate at higher output speeds. Both types of operation require additional motor current. The direction of the motor current across the d-axis, provided by the motor controller, determines the desired effect.
Differences Between The Permanent Magnet Motor And Asynchronous Motor:
01. Rotor Structure
Asynchronous motor: The rotor consists of an iron core and a winding, mainly squirrel-cage and wire-wound rotors. A squirrel-cage rotor is cast with aluminum bars. The magnetic field of the aluminum bar cutting the stator drives the rotor.
PMSM Motor: The permanent magnets are embedded in the rotor magnetic poles, and are driven to rotate by the rotating magnetic field generated in the stator according to the principle of magnetic poles of the same phase attracting different repulsions.
02. Efficiency
Asynchronous motors: Need to absorb current from the grid excitation, resulting in a certain amount of energy loss, motor reactive current, and low power factor.
PMSM Motor: The magnetic field is provided by permanent magnets, the rotor does not need exciting current, and the motor efficiency is improved.
03. Volume And Weight
The use of high-performance permanent magnet materials makes the air gap magnetic field of permanent magnet synchronous motors larger than that of asynchronous motors. The size and weight are reduced compared to asynchronous motors. It will be one or two frame sizes lower than asynchronous motors.
04. Motor Starting Current
Asynchronous motor: It is directly started by power frequency electricity, and the starting current is large, which can reach 5 to 7 times the rated current, which has a great impact on the power grid in an instant. The large starting current causes the leakage resistance voltage drop of the stator winding to increase, and the starting torque is small so heavy-duty starting cannot be achieved. Even if the inverter is used, it can only start within the rated output current range.
PMSM Motor: It is driven by a dedicated controller, which lacks the rated output requirements of the reducer. The actual starting current is small, the current is gradually increased according to the load, and the starting torque is large.
05. Power Factor
Asynchronous motors have a low power factor, they must absorb a large amount of reactive current from the power grid, the large starting current of asynchronous motors will cause a short-term impact on the power grid, and long-term use will cause certain damage to the power grid equipment and transformers. It is necessary to add power compensation units and perform reactive power compensation to ensure the quality of the power grid and increase the cost of equipment use.
There is no induced current in the rotor of the permanent magnet synchronous motor, and the power factor of the motor is high, which improves the quality factor of the power grid and eliminates the need to install a compensator.
06. Maintenance
Asynchronous motor + reducer structure will generate vibration, heat, high failure rate, large lubricant consumption, and high manual maintenance cost; it will cause certain downtime losses.
The three-phase Permanent magnet synchronous motor drives the equipment directly. Because the reducer is eliminated, the motor output speed is low, mechanical noise is low, mechanical vibration is small, and the failure rate is low. The entire drive system is almost maintenance-free.
The motor is excited by rare earth neodymium iron boron permanent magnet materials and is supplied with a permanent magnet special frequency converter. It has the characteristics of large starting torque, wide speed range, compact structure, small size, lightweight, low noise, high power factor, and high efficiency. It is an ideal power choice for high-efficiency and energy-saving air compressors.
1. The motor can operate normally under the following conditions:
1.1 The ambient temperature does not exceed 40℃;
1.2 Relative humidity ≤90%;
1.3 The altitude does not exceed 1000m.
2. The rated voltage of the motor is 380V, also according to user requirements.
3. The reference work system of the motor: S1.
4. Insulation grade: F grade.
5. Protection level: IP55.
6. Motor structure and installation type: B3, B35.
7. The motor outlet is located on the top of the base, or it can be located on the right or left of the base according to user requirements.
8. Motor service factor: 1.15, 1.2 (or as per technical agreement).
Analysis on the Application of Modern Permanent Magnet Motor Technology
1. Application of permanent magnet electromechanical technology to the home appliance market
The application of permanent magnet motor technology to the home appliance market is manifested in VCDDVD and computers. At present, it has gradually formed the development of industrialization, and has gradually expanded to multi-phase variable speed drives. For example, people use Inverter air conditioners use modern permanent magnet motor technology to improve the operating efficiency of the air conditioner, gradually reduce the volume of the air conditioner motor, and minimize the noise caused by the air conditioner.
2. Application of permanent magnet electromechanical technology in the elevator market
The permanent magnet motor variable speed system has been used in the elevator market for almost 10 years. For example, by using a low-speed rare earth permanent magnet motor as the elevator traction machine, the use of rare earth permanent magnet motor can save elevator use 20 % of electric energy. Modern permanent magnet motors are usually used in the field of variable-speed drive systems with large load changes and high speed adjustment requirements.
3. Application of permanent magnet electromechanical technology in industrial and mining enterprises
With the development of permanent magnet motors, large torque permanent magnet motors have been well developed, especially the successful launch of permanent magnet variable frequency motors on the market has given heavy industrial and mining enterprises new choices. Since the output torque of the permanent magnet motor is large enough, the use of the mechanical transmission is reduced and the speed is controllable. It can run at low speeds. Therefore, the application of the fluid coupling is eliminated, which saves the cost of purchasing related equipment and the maintenance of the above two equipment, which reduces the safety risk, so the permanent magnet variable frequency motor is very popular in many industrial and mining enterprises. Because of its variable frequency speed regulation function, it provides a strong guarantee for users to improve production efficiency and save electric energy. Therefore, modern permanent magnet variable frequency motors are a necessary choice for industrial and mining enterprises to upgrade their equipment in the future.
ENNENG is dedicated to providing customers with stable and energy-efficient permanent magnet motors and solutions, not only saving large amounts of energy and cost for our customers but also contributing to the energy conservation and emission reduction of the social.