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[Application of frequency converter] Application fields of frequency converter Application examples of frequency converter

Category : Instrumentation

[Applications of frequency converters] Application fields of frequency converters Application examples of frequency converters

Application fields of frequency converters

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Variable-frequency Drive (VFD) is a power control device that applies frequency conversion technology and microelectronics technology to control AC motors by changing the frequency of the motor’s operating power supply. The frequency converter is mainly composed of rectifier (AC to DC), filtering, inverter (DC to AC), braking unit, drive unit, detection unit, microprocessing unit, etc. The inverter relies on the switching of the internal IGBT to adjust the voltage and frequency of the output power supply, and provides the required power supply voltage according to the actual needs of the motor, thereby achieving the purpose of energy saving and speed regulation. In addition, the inverter also has many protection functions. , such as overcurrent, overvoltage, overload protection, etc. With the continuous improvement of industrial automation, frequency converters have also been widely used.

According to Xichi Electric’s industry experience over the years, frequency converters can be mainly used in 32 classic industry fields, such as: air conditioning loads, crusher loads, large kiln calciner loads , compressor load, rolling mill load, converter load, hoist load, roller load, pump load, crane, dump truck load, wire drawing machine load, transport vehicle load, elevator elevated tour bus load , feeder loads, stacker-reclaimer loads, fan loads, mixer loads, spinning machine loads, special power supply loads, etc.

Application examples of frequency converters

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1. Frequency converters are used in air conditioning loads

Office buildings, shopping malls, some supermarkets, and factories all have central air conditioners. In summer, electricity consumption During peak hours, air conditioning uses a lot of electricity. In hot weather, the power consumption of air conditioners in Beijing, Shanghai, and Shenzhen accounts for more than 40% of peak power. Therefore, using a frequency conversion device to drive the refrigeration pump, cold water pump, and fan of the air conditioning system is a very good energy-saving technology. At present, there are many companies across the country that specialize in air conditioning and power saving, and the main technology is frequency conversion speed regulation and power saving.

2. Frequency converters are used in crusher loads

Many crushers and ball mills are used in metallurgical mines and building materials. The effect of frequency conversion on this type of load is Significantly.

3. Frequency converters are used in large-scale kiln calciner loads

In the past, most of the large-scale industrial rotary kilns (converters) such as metallurgy, building materials, and caustic soda Use DC, commutator motor, slip motor, cascade speed regulation or intermediate frequency unit speed regulation. Since these speed control methods may have slip rings or have low efficiency, many units have adopted frequency conversion control in recent years, with excellent results.

4. Frequency converter is used in compressor loads

Compressors also belong to the widely used load category. Low-pressure compressors are commonly used in various industrial sectors, and high-pressure and large-capacity compressors are widely used in steel (such as oxygen generators), mining, fertilizers, and ethylene. The use of variable frequency speed regulation brings the advantages of small starting current, energy saving, and optimized equipment service life.

5. Frequency converters are used in rolling mill loads

In the metallurgical industry, large-scale rolling mills used AC-AC frequency converters in the past. In recent years, AC-DC frequency converters have been adopted. -AC frequency converter, rolling mill AC has become a trend, especially in light-load rolling mills. For example, the multi-stand aluminum rolling mill unit of Ningxia National Aluminum Products Factory uses a universal frequency converter to meet the requirements of low-frequency start-up with load and synchronous operation between racks. Constant tension control, simple and reliable operation.

6. Frequency converter is used in hoist loads

Wind loads adopt frequency conversion speed regulation, which is stable and reliable. The blast furnace winch equipment in the iron plant is the main iron-making raw material transportation equipment. It requires smooth starting and braking, uniform acceleration and deceleration, and high reliability. Originally, cascade, DC or rotor series resistance speed regulation methods were used, which had low efficiency and poor reliability. Using AC frequency converter to replace the above speed regulation method can achieve ideal results.

7. Frequency converters are used in converter loads

For converter loads, using AC frequency conversion to replace DC units is simple, reliable and stable in operation.

8. Frequency converters are used in roller conveyor loads

Roller conveyor loads are mostly in the steel and metallurgical industry. AC motor frequency conversion control can be used to improve Equipment reliability and stability.

9. Frequency converters are used in pump loads

Pump loads are large in volume and wide in scope, including water pumps, oil pumps, chemical pumps, mud pumps, Sand pumps, etc., include low-pressure small and medium-capacity pumps, as well as high-pressure large-capacity pumps.

Many water pumps of water companies, chemical pumps, reciprocating pumps in the chemical and fertilizer industries, mud pumps in non-ferrous metals and other industries use variable frequency speed regulation, all of which produce very good results.

10. Frequency converters are used in loads such as cranes and dump trucks

Loads such as cranes and dump trucks have large torques and require stable operation, with frequent positive and negative movements. Reliability is required. Frequency conversion devices control cranes and dump trucks to meet these requirements.

11. Frequency converters are used in wire drawing machine loads

Wire drawing machines that produce steel wire require high-speed and continuous production. The steel wire strength is 200Kg/mm2, and the speed control system requires high precision, high stability and synchronization.

12. Frequency converters are used in transporting vehicle loads.

The raw coal loading trucks in coal mines or the molten steel transport trucks in steel plants use frequency conversion technology.The effect is very good. It has fast starting and stopping, strong overload capacity, flexible forward and reverse rotation, smooth coal surface and correct weight (no more or less loading). It basically does not require manual operation, which improves the production efficiency of raw coal and saves electric energy.

13. Frequency converters are used in elevators and elevated tourist vehicles.

Since the elevator is a man-carrying tool, the drag system is required to be highly reliable and frequently used. The acceleration, deceleration and forward and reverse rotation of the elevator improve the dynamic characteristics and reliability of the elevator, while increasing the sense of security, comfort and efficiency of the elevator ride. In the past, elevators mostly used DC speed regulation. In recent years, they have gradually switched to AC motors with variable frequency speed regulation, both in Japan and Germany. Many elevator factories in our country are rushing to equip elevators with variable frequency speed regulation. For example, Shanghai Mitsubishi, Guangzhou Hitachi, Qingdao Fuji, Tianjin Otis, etc. all use AC variable frequency speed regulation. Many elevators originally produced have also undergone frequency conversion transformation.

14. Frequency converters are used in feeder loads

In metallurgy, electric power, coal, chemical and other industries, there are many feeders, regardless of disc Whether it is a feeder or a vibrating feeder, the effect of frequency conversion speed regulation is very significant. The disc feeder of the sulfuric acid production line of Jilin Chemical Company’s dye factory originally used slip speed regulation, had small low-frequency torque, had many faults, and often stuck. After adopting variable frequency speed regulation, because it is an asynchronous machine, it has high reliability and energy saving. More importantly, the closed loop with the temperature transmitter ensures the accuracy of conveying materials, preventing accidents caused by excessive over-temperature of oxidant conveying and ensuring production. of orderliness.

15. Frequency converters are used in stacker-reclaimer loads

Stacker-reclaimer is the main equipment for stacking materials in coal yards, docks, and mines. , the main function is stacking and unloading materials. Automatic stacking and semi-automatic retrieval are realized, which improves the reliability of the equipment. The equipment runs smoothly without impact and shaking. The retrieval process rotates and regulates speed according to the law of 1/cosφ, which improves the efficiency of bucket wheel rotation and retrieval and the efficiency of belt transportation of coal. Uniformity, very popular among workers.

16. Frequency converters are used in fan loads

Fan loads are large-volume and wide-ranging equipment, such as steel plants, power plants, non-ferrous metals, mines, etc. It is widely used in chemical, textile, chemical fiber, cement, paper and other industries. Most of them use adjusting the baffle opening to adjust the air volume, which wastes a lot of electrical energy. Using variable frequency speed regulation can save energy, reduce mechanical wear, and extend the life of the equipment.

17. Frequency converters are used in mixer loads

There are many mixers in the chemical and pharmaceutical industries. The advantages of using variable frequency speed regulation instead of other speed regulation methods are Trinidad and Tobago.

18. Frequency converters are used in spinning machine loads

The spinning process is complex, with many work stations, requiring tension control, and some require positioning control. The effect of frequency conversion speed regulation is good.

19. Frequency converters are used in special power loads

Many power supplies, such as experimental power supplies and aircraft drag power supplies (400Hz), can be completed with frequency converters. The advantage is low investment and effective results. Fast, small and easy to operate.

20. Frequency converters are used in paper machine loads

Paper machines in my country’s paper industry that require high precision mostly use SCR DC speed regulation. Some use slip motors and commutator motors. The reliability and accuracy are not high due to the presence of slip rings and carbon brushes. As a result, papermaking machinery is lagging behind. The general speed is only about 200m/min, which is difficult to compare with the 2000m/min abroad. Therefore, frequency conversion of papermaking machinery has become a general trend.

21. Frequency converters are used in laundry and ironing equipment loads

In the past, washing machines and ironing equipment in larger hotels used mechanical speed regulation or pole changing. Speed ​​adjustment can only provide one speed or several speeds, which is not ideal for fabrics that require repeated washing and ironing. Using variable frequency speed regulation, the efficiency of the washing machine is greatly improved.

22. Frequency converters are used in musical fountain loads

Music fountains are very popular with tourists. The height and volume of water are controlled by frequency converters. of.

23. Frequency converters are used in mechanical loads such as grinders

Grinder spindles have high speeds and require high power supply frequencies, including 200Hz and 400Hz. Even 800Hz. In the past, the power supply for the spindle motor was mostly driven by an intermediate frequency generator set. The intermediate frequency unit is large in size, low in efficiency, noisy and has poor accuracy.

24. Frequency converters are used in cigarette making loads

The cigarette making machines imported by the cigarette industry in the past, whether Molin 8 or Molin 0, are not Stepless speed regulation. Therefore, in the cigarette industry, it mainly solves the problems of stepless speed regulation and reliability. The technology is simple, the frequency converter is simple to use, and the results are great.

25. Frequency converters are used in vibration reduction and noise reduction loads

Many loads, such as large air compressors, medium frequency units, etc., are noisy and Big vibration. Using frequency conversion technology, it can reduce vibration and noise to within standards.

26. Frequency converters are used in printing and dyeing machine loads

Most printing and dyeing machines are multi-unit equipment that works together. The process requires each unit to run synchronously at the same linear speed and keep the tension constant. Otherwise, quality problems such as fabric breakage, tangling, uneven color, insufficient color, and excessive shrinkage will occur. In the past, printing and dyeing machinery used DC speed regulation systems regardless of the common power supply mode or the separate power supply mode.

Due to the inherent shortcomings of DC, the printing and dyeing industry gradually adopts ACFrequency conversion technology. The rotary screen printing machine is composed of a cloth feeding unit, a printing unit, a drying room guide unit and a cloth dropping unit. It is a complex speed control system in printing and dyeing. Frequency conversion speed regulation is used to form speed chain control. Good synchronization performance, high precision and high reliability.

27. Frequency converters are used in injection molding machine loads

Injection molding machines are key equipment for plastic processing and molding. They are large in number and consume a lot of power. In the past, most power-saving methods were to convert the △-shaped (triangle-shaped) into a Y-shaped (star-shaped) to save power, and the effect was average. Using variable frequency speed regulation does not change the original structure of the injection molding machine, and controls the pressure or flow of several processes of the oil pump (such as mold clamping, mold clamping, injection molding, pressure maintaining, demoulding, ejection, etc.), which can save 20% to 52% of electricity. %, which has better replaced the previous proportional valve throttling speed regulation method and greatly reduced energy consumption. Many injection molding factories in the Pearl River Delta have carried out frequency conversion transformation. When modifying the injection molding machine, pay attention to the mold closing acceleration, otherwise the output will be reduced, and pay attention to the harmonic interference at the input and output ends.

28. Frequency converters are used in environmentally friendly loads such as sewage treatment.

Environmental protection is paying more and more attention, and it is related to the environment on which human beings live. Since then, clean energy and green cities have emerged. Frequency conversion speed regulation can be used for environmentally friendly loads in three aspects. The first is industrial sewage treatment, the second is waste power plants, and the third is the control of industrial smoke, exhaust, and dust removal.

29. Frequency converters are used in glass, ceramics, pharmaceuticals, beverages, food, packaging and other production line loads

Glass, ceramics, pharmaceuticals, beverages, food , packaging and other production lines adopt frequency conversion speed regulation, and have achieved good results.

30. Frequency converters are used in offshore oil production platform loads

It is much better to use AC motor frequency control for oil drilling than DC speed control, especially It is used in sandy and dusty places because the AC motor is reliable. Offshore oil drilling platforms require frequency conversion speed control devices.

31. Frequency converter is used in electric submersible pump loads

Oil production by electric submersible pump is a way of oil production in oil fields. Electric submersible pumps mostly work in oil wells below 1800m. Most of them use power frequency full voltage startup and constant speed operation. They have the following disadvantages:

☆Excessive starting current will damage the motor insulation

☆Produces impact torque, damaging the pump structure;

☆The pump suddenly produces a large suction force, which can easily suck in sand, causing the pump to jam. Moreover, there is no voltage stabilizing system and the underground liquid level fluctuates greatly, resulting in unstable voltage and current, causing over-excitation and under-excitation of the submersible motor, causing failure.

32. Frequency converters are used in polyester chip loads

Polyester chips are one of the main products in the petrochemical industry. Due to the high precision of frequency conversion speed regulation, Convenient for multiple controlsPoint control, stable and reliable, using variable frequency speed regulation can increase product quality and bring great benefits to enterprises. Many companies use variable frequency speed regulation technology when expanding capacity.

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