With the urgent need for energy conservation and emission reduction in my country and the relatively mature magnetic steel technology, permanent magnet motors have been developed in China in recent years, and the technology has been greatly improved.
1. There are three main types of permanent magnet synchronous motors on the market:
1. Asynchronous start permanent magnet motor
This type of motor developed earlier and is mainly used in textile machinery, oil pumps, oil pumps, etc. The universal power supply can be started directly, the control cost is low, and it is easy to use. However, due to the existence of a permanent magnet synchronous switch in the linear rise, it is difficult to achieve synchronization for large inertia loads, and it is easy to lose magnetism under large currents, so the load has limitations, so the load is large.
2. Oil pump servo motor
This motor is imported from Europe, the production base is in Ningbo, and it is mainly used in the hydraulic system of the injection molding machine. According to the technological requirements of the injection molding machine, the invention is fast and flexible, and the speed is fast. The efficiency can reach about 94-95%, and can reach more than 30% in the transformation of the injection molding machine. Beautiful appearance and small size. Defect: Since the servo motor has the characteristics of positioning, speed and torque, the S34 intermittent working system is used as the design feature.
The permanent magnet synchronous motor introduced above is mainly used in elevators, injection molding machines, compressors, bump pumping units, household appliances and other industries. As a permanent magnet motor emerging in the energy-saving industry in recent years, its control technology and motor design level are relatively low, and the materials used are not uniform, resulting in great differences in energy efficiency. Users believe that all permanent magnet motors are ultra-efficient. The supervision and spot check of the motor centralized department shows that about 50% of the permanent magnet motors have not reached the third-level energy efficiency stipulated by GB18613-2012 asynchronous motors, so this phenomenon is quite confusing. To this end, the state has issued the "Permanent Magnet Synchronous Motor Energy Efficiency Limits and Energy Saving Levels" GB30253-2013.
3. Special elevator traction machine
The multi-stage motor controlled by the frequency converter is used to replace the original gearbox, which improves the system efficiency, reduces noise and reduces the mechanical failure rate. This special shape cannot be applied to conventional instruments, and its efficiency is low.
Permanent magnet air compressor
Second, the permanent magnet air compressor mainly realizes energy saving through the following three aspects:
1. Frequency conversion speed regulation
The permanent magnet air compressor adopts variable frequency speed regulation, which can greatly improve the work efficiency. Therefore, it has great energy saving potential. However, ordinary air compressors cannot rule out the possibility of running at full load for a long time. Therefore, the capacity of the motor can only be determined according to a large number of needs. Therefore, the planned capacity of ordinary air compressors is often too large. In actual operation, the share of no-load operating time is also relatively high.
2. Motor speed
When the demand is small, the permanent magnet air compressor can reduce its operating power by adjusting the motor speed, so as to meet the user's energy saving needs.
3. Pressure
The pressure stability of the permanent magnet air compressor can be reduced to no pressure fluctuation difference, so that the operation of the air compressor system can meet the low pressure required for production and reduce the power loss caused by the upward pressure fluctuation.
