Frequency conversion motor with the emergence of ndfeb magnets, permanent magnet motor obtained fast development, the permanent magnet frequency conversion motor speed control system into all walks of life, to replace induction motor variable frequency system. Permanent magnet motor + special inverter control method in the application of air compressor system, has achieved good energy saving effect. Now most of the air compressor using asynchronous motor + inverter control mode, by adjusting the motor speed, guarantee the working pressure constant, to reduce the working pressure of air compressor. Save the contactor control air compressor system for motor & other; Idle & throughout; Caused during the period of about 15%20% of the rated power energy loss. At the same time, reduce the operating pressure, reduces the power loss at work, so as to achieve better energy saving purpose. According to different pause time of air compressor system, frequency control of motor speed way than the contactor control mode, power saving rate up to 20 ~ 40%. Cost is higher, but this type air compressor system and driver with asynchronous electric reduced the opportunity to work with speed, efficiency is also the phenomenon of rapid decline, especially in the low frequency is run, the efficiency of the motor will be greatly reduced. Permanent magnet frequency conversion motor with magnetic steel because of its itself, excitation magnetic field is provided by permanent magnet and don't need to absorb reactive excitation power from the power grid, so the power factor of permanent magnet frequency conversion motor is up to 0. More than 93, so can be made more pole permanent magnet frequency conversion motor, shorten the winding end, reduce the copper loss, improve the efficiency of the permanent magnet frequency conversion motor, without worrying about the problem of low power factor. Permanent magnet relative to the asynchronous frequency conversion motor, frequency conversion motor in low frequency startup, asynchronous frequency conversion motor of main magnetic field is weak, low power factor, when starting current in 1. 5 ~ 2 times rated power down, just can achieve the rated torque. And permanent magnet constant frequency conversion motor of main magnetic field, almost all of the stator current for active current and starting current in 1 times the rated current, rated torque could be achieved. Small starting current, you can get bigger starting torque, system rises faster, also reduced the gasholder pressure fluctuations, good to ensure the stable and reliable operation of the system.
