双重预测PI算法在单晶硅生长炉中的应用

Application of Dual Predictive PI Algorithm on Single Crystal Silicon Growth Furnace

直拉法单晶硅直径的控制难点在于过程对象的大惯性、大滞后、非线性及多干扰。采用双重控制思想,快则治标,主控制器快速调整拉晶速度,快速影响直径;缓则治本,副控制器平稳调整液面温度,保证产品质量。针对对象的惯性和滞后,结合预测PI控制算法,提出双重预测PI控制算法。算法简洁,结果表明,采用双重预测PI控制算法,能够协调控制拉晶速度和液面温度,兼顾系统快速性和产品质量。特别在液面温度的控制上,该算法可以提高系统的工作频率,平稳且快速调整液面温度。控制系统运行稳定,该算法具有实用价值。

Czochralski method is used in the production of monocrystalline silicon. The process object has large inertia and delay, non-linearity and multi-interaction. So the diameter of the product is difficult to control. In this article, on the one hand, we use dual control algorithm to coordinate the casting speed and the temperature of liquid surface. On the other hand, we use predictive PI algorithm to solve the problem of large inertia and delay. Then the dual predictive PI control algorithm is put forward. The algorithm is very simple and has been used for simulation system. The results show that the control system is reliable and useful.