Design And Implementation Of Induction Motor Stator Resistance Fuzzy Observer

Direct Torque Control (DTC) is a new type of induction motor speed control methods. it is widely used because of Their innovative control thinking , simple control structure, direct control means and clear physical concept about signal processing. But accurate identification of stator resistance become a important issue in constraintting precise control of direct torque control system. The changes of stator resistance in relation with temperature rise, stator current, frequency and many other factors.it have variability, nonlinear, large inertia, so it is difficult to express precisly by explainning formula and establish a precise mathematical model. Because fuzzy inference particularly suited to dealing with uncertain complexity , so we can use fuzzy control theory to design stator resistance fuzzy observer to identify stator resistance.The key of fuzzy observer has good control results is to have good control rules. It adopt language direct-control rules in the design and did not require the precise object model, which makes control mechanism and strategy easily accepted and understood, simple designed, easily application. Most of the early fuzzy rules are based on expert experience, followed feedback and feedback control thinking, summarized a series of conditional statements that was same to fuzzy rules,realized those rules by computer. This model often was not accurate , greate affected by human factors.Therefore, many domestic and foreign scholars brought forward that extract fuzzy rules from in-out data. Here we used relevant statistical method to achieve the extraction rules.This article first built the experimental system to survey in-out data, and recognized motor static parameter tested in the system.;second it carried on the data cleaning to the survey data in order to obtain effective data used in establishing observer;Third it discussed correlation statistics algorithm based on fuzzy control theory using in-out data ; Finally the recognized method was validate. The experimental result indicate that stator resistance observer based on the fuzzy control theory can realize the real-time output of stator resistance, on the one hand it solve the difficulty that astator resistance unable to establish accurate mathematical model because of nonlinearity,large inertia and time changing.on the other hand the observer precisely track the stator resistance change value, reduce the flux observation error, thus further improve direct torque system's performance.