外文翻译--蒸汽发生器水位模糊控制研究(编辑修改稿)

外文翻译--蒸汽发生器水位模糊控制研究(编辑修改稿)内容摘要：

ly, but there is an opposite process at first. This phenomenon is called false water level phenomenon. III. DESIGN OF WATER LEVEL FUZZY CONTROLLER The conventional PID controller has a poor control performance to the steam generator that exist“ false water level” characteristics, showing a greater overshoot in the tracking time. But a welldesigned fuzzy controller is able to overe the false water level phenomenon, and has good control performance. A. Sstructure of Fuzzy Controller The structure showed in Figure 1. Choose the water level error (e) and change rate of error (ec) as input of the fuzzy controller, the output of the fuzzy controller is the added value of the valve opening signal Δu. Meanwhile, use the steam flow feedforward to overe the false water level phenomenon, use water flow feedback to overe fluctuations in water supply side . k1, k2 were water flow and steam flow transmitter conversion factor. To ensure the water flow to match the steam flow, k1 and k2 values should be equal to. B. Fuzzy theory, fuzzy subset and Membership Function The fuzzy Analects of e, ec and u are [6, 6], both with seven fuzzy sets NB (negative big), NM (negative middle), NS (negative small), ZO (zero), PS (positive small), PM (positive middle) and PB (positive big) to describe. e, ec and, Δu are all using triangular membership function (see Figure 2) Figure 2. Input and output variable membership function C. Fuzzy control rule table The establishment principle of fuzzy control rules are: when the error is large, the output control volume should give priority to eliminate error as soon as possible。 when the error is small, the output control volume should givepriority to prevent overshoot. Where ec is negative ,it shows that water level has a rising trend, if the water level is high at this time, then we should reduce the valve opening signal。 whereas, we should open the valve more. Through a prehensive analysis of expertise, the establishment of rule table shown in Table 1. Table 1. Fuzzy control rule table D. F。