电弧炉功率负荷微机控制系统

Power Charge Computer Control System of Electrometal Furnace

本文论述了电弧炉微机控制系统的工作原理、组成和设计方法。分析研究了系统的传递函数及数学模型。功率负荷控制主要基于电导平衡思想,它比只控制电流平衡思想更有效更稳定。该系统微机控制部分采取了有效的抗干扰措施,使系统能可靠地工作于强电磁干扰及粉尘大的恶劣环境。信号检测系统采用了精密的绝对值变换电路,克服了一般电流、电压变送器小信号时产生的非线性误差,因此在有效的工作区的检测精度均能达到0.1％以上。驱动系统采用了无触点交流开关。其线路设计采用过零触发电路。逻辑指令通过光电耦合器加到异或门保护电路上,随后与过零开关同步电路去一起开通可控硅。这种电路有效抑制了交流开关的射频干扰。增加了系统工作的可靠性。该系统成功地用于600KVA电弧炉并取得了节约电能、提高产量的明显经济效益。对于电流波动大的各种电弧炉,其工艺过程分为预热、熔化、还原三期的实时过程控制都可适用。例如:电弧炼钢炉、矽铁和钛渣电弧炉等。对于电流较稳定的埋弧炉控制效果会更好。

The paper Presented states the working principle, construction and designing method of the computer control system of electrometal furnace, and analyses the transmission function and mathematic model of the system. The power charge coutrol is mainly based on the balance of conductannce, it's more effective aud stationary than only controlling the balance of current. Adopted effecfive anti-interference measures, the system can work reliably under the obstruction of powerful electromagnetics as well as dusty environment. Employed an precise absolute value transition circuit in the signal check system, the non-linear errors produced by transferring small signs through common C(current) V(voltage) transducer are eliminated, there by, the check precision can reach over 0.1% in the effective working range. An alternating switch of non-touched point is taken in the driving system, and an over-zero trigger is adopted in its circuit. Through photo electric coupler, a logical order is added in an exclusive-OR gate protection circuit, then opens a silicon controlled rectifier along with a synchronous circuit with over-zero switch. This circuit effectivfly restrains the inter ference of radiofrequency of alternating-current switch, and increases the reliability of the system. This system has been success fully used in 600KVA electrometal furna ce and makes an evident economic benefit in economizing power and increasing productivity. It is suitable for the control of real-time process including pre-heat, melt and reduction three periods of all kinds of electrometal furnace with targe current vibration, e. g. steel-smelting furnace, furnace with silicon iron and titanian dregs and so on. It will be more effective to control the arc-buried furnace of stationarg current.