Abstract: High-voltage AC variable frequency speed control technology is a new type of electric drive speed control technology developed rapidly in the 1990s. It is mainly used for frequency conversion speed control of AC motors. Its technology and performance are far better than the previously used speed control methods. .

High-voltage AC variable frequency speed control technology is a new type of electric drive speed control technology developed rapidly in the 1990s. It is mainly used for the frequency control of AC motors, and its technology and performance are far better than the previously used speed control methods (such as Cascade speed control, fluid coupling speed control, rotor water resistance, etc.). According to the investigation of the large air-conditioning and refrigeration market, high-voltage inverters have been widely recognized by users for their remarkable energy-saving benefits, high speed accuracy, wide speed range, perfect protection functions, and convenient communication functions. Now it has become the first choice for the motor energy-saving method of the company. AC motor frequency conversion and speed regulation is a major means to save energy, improve production process, improve product quality, and improve operating environment. Frequency conversion speed regulation is recognized as the most promising speed regulation method both at home and abroad due to its high efficiency, high power factor, and excellent speed and braking performance.

After statistics on the original system, in the production process, the wind turbine baffle opening degree is mostly around 80%, and the power saving space is relatively large. We decided to carry out frequency conversion of the original system and adjust the wind pressure control from the original hydraulic coupler. Change to the frequency changer adjustment: Cancel the original hydraulic force coupler, uses the connection shaft to replace the fluid coupling between the electric motor and the hydraulic coupler, but by the frequency changer carries on the velocity modulation to the electrical machinery itself, finally achieves adjusts the kiln tail to warm up The pressure of the device (high temperature fan population) is the required value of working conditions; the inverter equipment is connected between the high pressure switch of the fan side and the motor to be modified, and the inverter is controlled to access the original DCS system. Motors and high pressure circuit breakers still use the original equipment. In order to fully ensure the reliability of the system, frequency converters have been installed with frequency bypass devices, retaining the baffles (valves) on the original pipeline. In this way, when the inverter fails, the motor can be switched to operate at the power frequency status, and the damper is still used for air volume adjustment.

Practice has proved that there is little opportunity for the frequency converter to require the power frequency bypass operation, and the bypass device can be completely eliminated, which saves space in the power room and reduces investment, so that the valve support in the pipeline can be further removed and the pipeline resistance can be reduced. According to the reporter of the Refrigeration Express, after adopting the inverter, the system is stable and reliable, the speed of the hydraulic coupler is cancelled, the defects of high mechanical and hydraulic failure rates are eliminated, the operation rate is increased, the maintenance cost is reduced, and the running vibration and noise of the motor are obvious. Falling; the motor does not need long-term high-speed operation, the operating current is greatly reduced, and the power saving effect is significant.

Through the high-voltage frequency conversion technological transformation of the high-temperature fans of cement clinker production lines, before making plans, we must fully understand the production process and operation process, understand the adjustment methods of air volume and air pressure, and do a good job of the various process parameters before the transformation ( The statistical work of time, air volume, wind pressure, etc., equipment parameters (valve opening, operating current, etc.) provides basic data for the estimation of energy-saving effects and the formulation of technical solutions. Understand the operating load conditions and characteristics, determine the frequency converter selection. For high-temperature fans and other equipment of cement clinker line, it is recommended that the inverter be of a voltage source type, a high-high structure, which can be exempted from the output step-up transformer; for the capacity selection, it can be appropriately amplified by one level.