Comparison of the most popular domestic and foreig

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Comparison of domestic and foreign frequency converters

the function of the frequency converter is to change the 50ee power supply into a continuously adjustable frequency power supply, or it can liberate the power supply from 50Hz, so that the AC induction motor has the freedom of speed. In recent years, due to the rapid development of power electronics technology, frequency conversion has created beneficial conditions for the realization of small tonnage experimental machines. The performance of the device is getting better and better, but the price is decreasing year by year. This provides very good conditions for vigorously promoting the application of frequency converters. Due to the superior controllable performance and remarkable energy-saving effect of frequency converter, and people's understanding of frequency converter is becoming clearer and clearer, it has become a consensus to use frequency converter to transform old equipment and assemble new equipment. At present, most of the domestic market is occupied by imported machines, but the domestic inverter industry is stubborn. From the perspective of users, how to treat domestic and imported inverters? Domestic machines are cheap and imported machines have many functions. How to choose the most cost-effective machine? This paper makes a simple comparison between the two:

for advanced machines, imported machines should be selected for high-pressure machines. It is more affordable to choose domestic machines for popular machines. There are many classifications of frequency converters, which are roughly divided into three categories for the convenience of Narration:

1.1 advanced

machines contain flux vector control or direct torque control. It has accurate control force on the speed and torque of the motor, and can automatically test the parameters of the motor. The starting torque is large and the noise is small. It can realize synchronous operation, proportional operation, PI control, closed-loop speed or spindle position control, computer communication and PIC connection, etc

applicable occasions: elevator, printing mechanism, paper machinery, etc

1.2 high voltage type

the input/output voltage is more than 3000V, and the power of this type of machine is more than 1000kW. When selecting a microcomputer controlled pressure testing machine, you can refer to the above standards for considering the quality of equipment, so it can also be called high voltage large capacity type

applicable occasions: fans above 500kW, oil refining equipment, mining machinery, etc

1.3 popular

does not contain flux vector control, only v/f control, simple structure and low price

suitable occasions: water pumps, fans, wire feeders in steel mills, extruders in the plastic industry, wire pullers in the building materials industry, various belt conveyors for feeding inside sensors, hoists in mines, etc... according to the author's incomplete investigation, the first two models are in the development stage within 12 to 16 months of quality loss, and no mature products have been found so far

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