A control method for a temperature control system of a crucible descent method crystal growth furnace

Abstract

The present invention discloses a control method for a temperature control system of a crucible descent method crystal growth furnace. The temperature control system is mainly composed of a PLC controller, an SCR power regulator, a heating rod, a high-precision thermocouple and other components. The present invention uses PLC to design a fuzzy decoupling controller. First, the temperatures of the upper and lower temperature zones are collected in real time, and the temperature data is transmitted to the PLC controller. The error E and the error change rate EC are calculated. The controller adjusts the heating power of the upper and lower temperature zone heating rods in real time according to the error between the actual value and the set value of the temperature of the upper and lower temperature zones and the error change rate through a pre-designed offline fuzzy rule query table, thereby achieving the purpose of decoupling and precise temperature control. Specifically, the corresponding output control quantity can be obtained by traversing the above-mentioned offline fuzzy rule query table. The control quantity is converted by D / A and then adjusted by the SCR power regulator to adjust the power of the heating rod, thereby achieving the purpose of no overshoot during the heating process, stable temperature control process and short adjustment time.

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