Yan Limei

Study of variable-pitch wind turbine based on fuzzy control

First, the analysis of developing status of wind turbine control strategy has been made; Second, some mathematical models about aerodynamic parts are established according to the principle of the wind power generating units various parts. At the same time, some sub-modules of the wind turbine are established in MATLAB. At last, the control strategy based on Fuzzy controller is design and simulated by MATLAB/simulink. Both in the low wind speed and high speed the power output of the generator can quickly reached a stability (about 4s), which improve the control system respondent time.

The study on new energy saving controller for oil-pumping units in oilfield

The energy-saving effect of Y/Δ change-over controller is better than the silicon controlled rectifier(SCR) voltage regulating style when the load rate of oil-pumping unit is low; but the silicon controlled rectifier(SCR) voltage regulating style is better than the energy-saving effect of Y/Δ change-over controller when the load rate of oil-pumping unit is high. Based on high-precision three-phase electrical energy measurement IC-ATT7022A, a new energy saving controller of combining the advantages of both controllers is designed. On the analysis of based on the principle of voltage regulating and energy saving of electric motor of pumping units. This paper analyzes the systems hardware and software design. Through the installation of Y/Δ-SCR controller and comparison tests at the scene in five oil wells, every well saves 21000 kW.h annual.

Selecting location of transformer substation based on FAHP

Because of many factors and hard to make a decision, a fuzzy analysis hierarchy process is applied to select location of transformer substation to avoid the problem of disaccord of judgment matrix in analysis hierarchy process. Fuzzy analysis hierarchy process works as follows: firstly, to build the fuzzy consistent matrix by building hierarchy structure charts, then to synthesize all schemes to obtain the optimum location of transformer substation. The 220 kV transformer substation location is evaluated to obtain the optimum location, finally identify this methodpsilas efficiency and correctness.

Research of Uniform Stream Fuzzy Optimization Control in Power-Plant Straight-heating Boiler

On the basis of bias-flow analysis of burning system about power-plant straight-heating boiler and its countermeasures, a control scheme is given for the three fuzzy controller to be built by three pipes export absolute temperature-difference as the input , the openness valve as the controlled object. After realizing this control scheme, the problem of coked heat-pipes in burning process has be resolved perfectly. It makes the heat-pipes life increase more than three times. The result of in real running shows the new design scheme is in reason and in effect.

The stability analysis and planning for multivariable linear time-delay systems and its application

Based on Lyapunovs theory of stability, analysis on a control process of oil-water separation with time-delay, coupling and uncertainty in the unite station, is presented in this paper. An equation of sufficient condition for multi-variable linear delayed systems with delayed independent stabilization is derived and another forms are also given. Based on this, several simple criterions for judging independent stabilization from linear delayed system are presented. We also discuss the exponential stability for delayed system and also provide the sufficient condition of exponential stability with any appointed convergent rate and its corresponding deductions. Using these conditions, we can choose a set of suitable parameters to reduce the conservation. By calculating and being compared with methods of the literature, the results show that our methods have less conservation.

Stability analysis for a kind of multi-variable linear systems with delayed state

Based on Lyapunovs theory of stability, a equation of sufficient condition for multivariable linear delayed systems with delayed independent stabilization is derived and another forms are also given. Based on this, several simple criterions for judging independent stabilization from linear delayed system are presented. We also discuss the exponential stability for delayed system and also provide the sufficient condition of exponential stability with any appointed convergent rate and its corresponding deductions. Using these conditions, we can choose a set of suitable parameters to reduce the conservation. By calculating and being compared with methods of the literature, the results show that our methods have less conservation.