Fluidized Bed Temperature Control System Based on Virtual Instrument Technology and Fuzzy PID Algorithm

Abstract

The fluidized bed is a complex system with a big lag, time-varying and non-linear. The conventional-PID methods are simple, practical, and high reliability. However, choosing and adjusting PID parameters rely on manual way. It is difficult to choose appropriate values when temperature requirement is higher. Inappropriate values may cause large overshoot and low control precision. Thus, in order to obtain more accurate and rapid PID control parameters and to avoid errors caused by human factors, the fuzzy control and PID algorithm were applied to the fluidized bed furnace temperature control system. The Fuzzy-PID controller was designed and the three PID parameters' self-tuning was realized. Simultaneously, the upper computer and the lower computer were designed. The lower computer mainly completed temperature measurement and adjustment functions. The collected temperature was transferred back to the upper computer at regular intervals. The upper computer was designed by virtual instrument technology. Practical operation shows that the temperature variation is below 0.3 when heating oven is in stable state and is close to the ideal PID response curve, which meets the average requirements of the fluidized bed heating oven. As an advanced reactor, fluidized bed was widely used in industrial process such as combustion, gasification and catalytic cracking[1].As the temperature affect the gas product composition of the fluidized bed, so improving the furnace temperature utilizing the automatic control system is one of the important issues furnace. The fluidized bed heating oven is heated by resistance wire heating and cooled by natural cooling. The temperature control after the adjustment is slow. It is a complex system with a big lag, time-varying and non-linear. Currently, the conventional-PID methods were taken to control the fluidized bed heating oven's temperature. This method is simple, practical, and high reliability. However, choosing and adjusting PID parameter rely on manual way, it is difficult to choose an appropriate values .Inappropriate values may cause large overshoot and low control precision. Thus, in order to obtain more accurate and rapid PID control parameters and to avoid errors caused by human factors, the fuzzy control and PID algorithm are applied to the fluidized bed furnace temperature control system. The self-tuning fuzzy PID controller is designed. Compared with the outdated control methods, PC control is more flexible and even more long-range.