The Adaptive Control Of Electric Arc Furnace

With the development of economic, there are more and more new higher power electric arc furnace in china, most of them are even advanced in technology. But the control technology and operation level of electric arc furnace are still far from advanced level of the world, which result a huge waste of the equipment production ability,energy waste and the low economic efficiency. It’s exist a lot of running space in the china’s control technology of electric arc furnace. It’s need to be give in-depth research to improve the level of metallurgical industry in our country, It’s also will bring great economic benefits and environmental value. For this reason, this paper discusses the controlling of electric arc furnace technology and electrical operation technology.Taking a30MVA six electrode arc furnace of being built by a company as the research object, and the paper gave in-depth analysis of the electro-hydraulic servo control system characteristics. Piston cylinder hydraulic servo system in the application is less, the paper from the structure of the piston cylinder, base on the fluid mechanics theory deduction, established hydraulic mathematic model of the system which is composed of direction proportional valve and piston cylinder.Research shows that, piston cylinder electro-hydraulic servo system is in essence a nonlinear system, the system damping and structure parameters changes with the movement of plunger. Classic automatic control technology on such system doesn’t work. In addition, arc has a very strong nonlinearity, the main influencing factors of arc are the arc voltage, electromagnetic field, arc length, arc temperature, medium density, and so on.The Current range of arc models are derived based on the these factors.It is apparent that these arc model hypothesis is not practical, because of the complicated environment in the furnace electric. This paper treated the arc as a black box, defines a nonlinear equivalent gain of the arc, which only the input/output are concerned. The finally simulation experiments in this paper shows that the arc is actually a "energy-spring",which in turn testified the nonlinear equivalent gain of the arc agree with real situation.This paper combined the forgetting factor recursive least square method with the adaptive control organically. Forgetting factor recursive least square method can effectively absorb new input data constantly, and ruled out the old data, so can be guarantee the real-time of system control information source.Since the adaptive control technology can track the system structure parameters changes real-time, minimize the difference of the input and feedback date variance so as to achieve the purpose of control.Based on the above, the paper developed adaptive control technology of the electric arc furnace of electrode regulation system, which was proved by simulation experiment. The experimental results show that this technology can track the input set very well, and can solve problem of the nonlinear time-varying of system parameters effective.in the end, the electric arc furnace in practical operation is discussed.