Comparison between domestic and imported inverter

The function of 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 electronic technology, the performance of frequency converter is getting better and better, while 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

for the advanced machine, the high-pressure machine is a new type of impact testing machine that can instantly measure and record the characteristic curve of materials in the process of impact. It is suitable to choose the imported machine. It is more affordable to choose domestic machines for popular machines. There are many classifications of frequency converters. For the convenience of narration, they are roughly divided into three categories:

1.1 advanced

machines contain flux vector control or torque direct control if in doubt. 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 is also more than 1000kW, 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

applicable occasions: water pumps, fans, wire feeders in steel mills, extruders in plastic industry, wire pullers in building materials industry, belt conveyors for various materials, hoists in mines, etc... according to the author's incomplete investigation, the first two models are in the development stage in China, and no mature products have been found so far. In particular, the high-pressure type is still a blank in China, and it is estimated that a test prototype will come out in two or three years

2 universal machines have a wide range of applications

there are many kinds of V/F control of universal machines in qutongling city; 1035 rdquo; The center line of the scientific and technological innovation development plan can be selected, such as straight line, square, cubic and their combinations, so it can meet the requirements of many occasions

the most important thing to realize frequency conversion is the load of water pump and fan. According to the information, the load power consumption of water pumps and fans accounts for 1/3 of the total consumption in China. If this kind of load popularizes frequency converters, the electricity saved will be more than the total power generation after the completion of the Three Gorges hydropower station. From this, we can see how important and urgent it is to transform this kind of load with frequency conversion technology. It is completely competent to play this role with a universal machine

requirements for frequency converter of water supply system:

1) the power capacity should be appropriate

(2) the frequency range of frequency conversion is 15hz-50hz

the frequency range of frequency conversion is relatively wide, which is enough for water pumps. When 50Hz is reached, it can be converted to electric power supply, and 15Hz water pumps will not produce water

(3) PID control

in order to stabilize the water supply pressure, a pressure closed loop is desired, so the frequency converter is required to have a PID (or pi

link.

(41 general enterprises have done mechanical performance experiments, physical experiments, chemical experiments) to give the necessary output signals

to send out the control signals or alarm signals of the water pump when the frequency reaches 50ie or 15 Xing

(5) complete protection function