磁感應電機軟啟動外文翻譯-文庫吧資料
2025-05-21 19:51本頁面
【正文】 t in some applications. Machines which have a varying start torque requirement, such as on load conveyers, or applications requiring a reduced initial torque such as pumping applications, or genset applications where the relatively slow application of current load will allow the genset to track the load are examples of situation where the current ramp soft start can be used to advantage. 。 . Soft Starters for Induction M otors Fuzzy controllers are very simple conceptually. They consist of an input stage, a processing stage, and an output stage. The input stage maps sensor or other inputs, such as switches, thumbwheels, and so on, to the appropriate membership functions and truth values. The processing stage invokes each appropriate rule and generates a result for each, then bines the results of the rules. Finally, the output stage converts the bined result back into a specific control output value. The most mon shape of membership functions is triangular, although trapezoids and bell curves are also used, but the shape is generally less important than the number of curves and their placement. From three to seven curves are generally appropriate to cover the required range of an input value, or the universe of discourse in fuzzy jargon. As discussed earlier, the processing stage is based on a collection of logic rules in the form of IFTHEN statements, where the IF part is called the antecedent and the THEN part is called the consequent. Typical fuzzy control systems have dozens of rules. Consider a rule for a thermostat: IF (temperature is cold) THEN (heater is high)This rule uses the truth value of the temperature input, which is some truth value of cold, to generate a result in the fuzzy set for the heater output, which is some value of high. This result is used with the results of other rules to finally generate the crisp posite output. Obviously, the greater the truth value of cold, the higher the truth value of high, though this does not necessarily mean that the output itself will be set to high, since this is only one rule among many. In some cases, the membership functions can be modified by hedges that are equivalent to adjectives. Common hedges include about, near, close to, approximately, very, slightly, too, extremely, and somewhat. These operations may have precise definitions, though the def
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