Principle of PID Control Parameter Adjustment for Industrial Kilns
The temperature control of industrial kilns needs to be precise and stable. The PID (proportional integral derivative) controller optimizes closed-loop control by adjusting three major parameters, and its core principle revolves around the logic of deviation correction.
The proportional parameter (P) outputs a control signal based on the deviation between the actual temperature of the kiln and the set value. The larger the deviation, the stronger the output adjustment. Increasing the P value can improve the system response speed, but if it is too high, it can lead to severe temperature overshoot and cause temperature oscillations inside the kiln; Reducing the P-value results in a delayed response and is prone to control lag.
The integral parameter (I) is used to eliminate static deviation and continuously correct the output by accumulating the deviation time integral value. When there is a fixed deviation in the kiln (such as a constant temperature difference during the insulation stage), an increase in the I value can accelerate the speed of deviation elimination, but if it is too high, it will exacerbate system oscillation; If the I value is too small, the static deviation is difficult to eliminate, which affects the quality of product firing.
Differential parameter (D) is adjusted in advance according to the deviation change rate to predict the temperature trend. When the heating or cooling rate of the kiln suddenly changes, an increase in D value can suppress overshoot and enhance stability, but excessive D value can amplify high-frequency interference (such as fuel pressure fluctuations), leading to control signal fluctuations; If the D value is too small, the response to sudden disturbances is insufficient.
The parameter adjustment should follow the sequence of "proportion first, then integration, and then differentiation": first adjust P to make the system close to the set value, then adjust I to eliminate the static error, and finally adjust D to optimize the dynamic response. Through repeated tests, find the parameter combination of "no overshoot, fast response, and stable operation" to ensure that the kiln and furnace temperature control accuracy meets the requirements of industrial production.
