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Application of SOWAKAM frequency converter energy-saving technology in coal mines

Many links in coal mine production consume a lot of electrical energy, such as lifting and transportation, underground ventilation, and exhaust. In this case, the application of frequency converters has brought good news to energy conservation in coal mine production. It not only improves the efficiency and quality of coal mine production, but also better saves electric energy and plays an important role in energy conservation and emission reduction.

1. SOWAKAM inverter and its working principle

The operating principle of SOWAKAM inverter

The main applications of frequency converters are frequency conversion technology and microelectronics technology. The basic working principle of the frequency converter is to control the power control equipment of the AC motor by changing the current frequency. In addition to running AC mechanical equipment, the frequency converter can also achieve energy saving and speed adjustment by changing the voltage and power frequency, effectively reducing the energy consumption of mechanical equipment and bringing greater economic benefits to coal mine electromechanical equipment. . In addition to saving energy, the inverter can also provide many protection functions, such as protecting some electromechanical equipment from overvoltage, overload, overcurrent, etc.

2.Application of SOWAKAM frequency converter in coal mine electromechanical equipment

2.1 Application in belt conveyor

At this stage, the use of frequency converters in coal mine electromechanical equipment is mainly reflected in belt conveyors, and its main operating principle is realized through the physical properties of the belt - elasticity. When the belt is at rest or running, the belt contains a large amount of energy. If some soft-starting devices are not added when starting, the energy in the belt will be released quickly. If excessive tension is generated, it will easily cause the belt to be damaged. The belt was torn off. Due to the emergence of frequency converters, this phenomenon has been greatly alleviated, and through its improvement of belt conveyors, it has brought many economic and social benefits to enterprises. Mainly manifested in the following aspects:

a) The frequency converter adds a soft start mode to the belt conveyor, so that the belt conveyor starts slowly during the driving process, so that the tension of the belt does not increase instantaneously, but increases slowly, and the energy in the belt It is also released slowly during soft starting, effectively preventing the belt from breaking during the starting process;

b) The use of frequency converters also enables the belt conveyor to achieve power balance when driven by multiple motors. When using a frequency converter for driving, usually one motor and one control device are used. When multiple motors are used at the same time, master control and slave control can be better realized, and power control can also be achieved. balance;

c) The use of frequency converters in belt conveyors can reduce the belt strength. It effectively extends the service life of the belt conveyor and reduces the requirements for belt strength. Therefore, it also indirectly reduces the mechanical and electrical requirements for coal mines. Equipment cost investment;

d) The application of frequency converters in belt conveyors can more efficiently extend the service life of electromechanical equipment, reduce the maintenance volume and maintenance costs of the equipment, and the belt conveyor has a heavy impact on mechanical equipment, parts, etc. during use. There is no force impact, which also greatly reduces the number of maintenance times and the amount of maintenance work on the belt conveyor.

2.2 Application of frequency converters in mine hoisting equipment

The main function of the lifting equipment is to transport ore, coal, waste rock or gangue along the mine shaft, as well as to lift personnel, equipment and equipment, etc. Therefore, a large amount of power consumption is generated during use. The use of frequency converters effectively improves the efficiency of the lifting equipment. Electrical energy usage efficiency. Mine lifting equipment plays an important role in the entire coal mine production. Its safety and quality have always been the key to ensuring the safety of coal mine production and preventing coal mine collapse accidents. Therefore, in the design of new mines and the renovation of old mines, mining machine lifting electrical equipment is given top priority. After multiple comparisons and based on the specific conditions of the mine, mechanical equipment suitable for coal mine production is selected. After using frequency converters, the advantages of using mine hoisting equipment are mainly reflected in the following aspects:

a) The application of frequency converters increases the control accuracy of mine hoisting equipment. Since frequency converters adopt magnetic flux vector control, the speed regulation performance of AC motors is almost equal to that of DC motors, and the control accuracy is very high;

b) The use of frequency converters improves the working reliability of mine hoisting equipment. The frequency converter uses electrical components, which have a longer life than others. And it has perfect protection function, which makes its working reliability very high when it is applied to mine hoisting equipment;

c) The use of frequency converters also reduces the maintenance workload of mine hoisting equipment, which not only improves the efficiency of equipment use, but also greatly reduces the maintenance and repair of staff, and reduces the work intensity of staff;

d) The use of frequency converter enables a wide range of speed regulation, stepless speed regulation, and good stability at low speeds.

2.3 Application of frequency converter in emulsion pump

The emulsion pump station is a very critical power device for high-pressure emulsion transportation in the mechanized production of general mining and fully mechanized mining in coal mines. It is the most common and essential equipment in modern coal mines. Its principle is simple: under normal circumstances, the emulsion pump station is equipped with two emulsion pumps and one emulsion tank. Only one of the two pumps can be working and the other is in standby, or the two can be operated in parallel. In the actual production process, the operation intermittent time of the emulsion pump station is not fixed, usually ranging from a few minutes to a few hours. At the same time, the entire hydraulic system must be in a state of preparation at any moment. In the hydraulic system A constant pressure must also be maintained at all times, resulting in the emulsion pump station having to operate continuously during the long-term production process. When the set pressure is reached, the unloading valve of the pump station itself operates, and then frequently rises to the set pressure again. action, resulting in large equipment losses, increased maintenance costs, and high electricity costs. Using frequency conversion technology has the following advantages:

a) The pressure signal can be provided to the frequency converter through the pressure sensor installed on the liquid supply pipeline. The frequency converter controls the operating speed of the emulsion pump station motor according to the pressure changes in the pipeline to ensure constant pipeline pressure.

b) The unloading valve of the pump itself no longer operates frequently, extending the service life and reducing costs.

c) Automatic monitoring technology realizes the intelligent mode of "unattended" and "liquid supply on demand", maximizing benefits.

3. Energy saving performance of SOWAKAM inverter in coal mine equipment

3.1 Energy saving performance of frequency converter in belt conveyor

After using the frequency converter, the energy-saving effect of the belt conveyor is mainly reflected in two aspects: system power factor and system efficiency:

a) The use of frequency converters can improve the system power factor. Under normal circumstances, coal mine equipment is designed with a relatively large margin, and most of it cannot operate at full load during operation. Electromechanical equipment often has a very small load at full voltage and full speed, and sometimes operates without load. This phenomenon makes the use efficiency of mechanical equipment too low, and no-load or light-load operation causes a lot of unnecessary power loss to the entire belt conveyor equipment. When the frequency converter is used in a belt conveyor, basically during the operation of the belt conveyor, the power factor reaches more than 0.9kW, which greatly improves the operating efficiency and basically eliminates the phenomenon of light load and no load;

b) The use of frequency converters can improve system efficiency. When the frequency converter is used, the motor and the reducer are directly connected, reducing the use of hydraulic couplings. Since the hydraulic coupling itself uses liquid to rotate, its efficiency is relatively low. Therefore, the use of frequency converters increases the efficiency of the entire belt conveyor system by 5% to 10%.

In addition, mines are generally far away from substations, and the voltage changes greatly at different times. The frequency converter itself has the function of stabilizing voltage, which also indirectly plays an energy-saving role.

It can be seen that the use of frequency converters to transform traditional belt conveyors will bring great benefits both in terms of technical improvements in coal mine machinery and equipment and in terms of economic benefits. With the development of the times, frequency converters have also Will be more widely used in belt conveyor equipment.

3.2 Energy-saving performance of frequency converters in mine hoisting equipment

Since the speed regulation method of the frequency converter is mainly slip power invariant, the energy saving effect during the speed regulation process is mainly reflected in the following two aspects.

a) Energy saving during the lifting process. When the mine winch is in a lifting state, the motor is in an electric working state. Since the winch is a constant torque load, the frequency converter achieves energy saving by adjusting its speed. When the speed is reduced, a corresponding degree of energy saving effect can be achieved.

b) Energy saving during descent. When the mine winch is in a descending state, the motor is in a power generation state, which is a process of converting potential energy into electrical energy. When an energy feedback type inverter is used, the inverter will return the converted electrical energy to the power grid, achieving energy savings.

3.3 Energy saving in variable frequency constant pressure liquid supply equipment

a) Save electricity. Since the emulsion pumping station on the underground coal mine working surface operates 24 hours a day, in fact, the total time for the emulsion pumping station's injection and racking and other processes is usually less than eight hours. However, in order to ensure liquid supply and other requirements, it can be done at any time. In order to be satisfied, it is necessary to make the emulsion pump station run uninterrupted throughout the day, which makes more than 66% of the energy consumption of the emulsion pump station is wasted work. Using frequency converter constant voltage control can effectively save electricity.

b) Increase the service life of the emulsion pump. When the emulsion pump station operates under power frequency conditions without liquid injection, the pressure of the entire hydraulic system is repeatedly pressurized through the pump body plunger, and then relieved through the unloading valve (relief valve). This not only wastes electrical energy, but also causes repeated pulsation. Impact pressure damages pipeline accessories, greatly shortens the service life of the pump body, and increases the system failure rate. After the application of variable frequency constant pressure automatic control, when there is no liquid injection in the underground working surface, the emulsion pump station will not operate, which greatly increases the service life of the emulsion pump.

c) Frequency conversion speed regulation realizes automatic control of pressure and flow. When the underground mining working surface begins to inject liquid, the pressure in the pipeline also changes, and the pressure sensor will send out a signal. The signal is fed back to the frequency conversion speed control device through the pressure detector. At this time, the frequency converter adjusts the speed of the emulsification pump through frequency conversion, thereby Adjust the pressure and flow to realize automatic control of liquid distribution and stabilize the pressure of the hydraulic pipeline.

4. Conclusion

The application of frequency converters in coal mine machinery and equipment is not only reflected in belt conveyors, mine hoisting and constant pressure liquid supply equipment, but also in water pumps and fans. In coal mining equipment such as winches. At this stage, China's use of frequency converters in these coal mine equipment is not extensive enough. Frequency converters have huge development prospects. They achieve control of electric energy by efficiently converting electric energy into different forms, and are of great significance to coal mine production. Significance. With the development of the times, I believe that more frequency conversion technologies will be developed and applied, and frequency converters will be more widely used.