欧洲风能技术论文122_EwecA_NON-LINEAR_CONTROL_ALGORITHM_FOR_IMPROVING_PERFORMANCE_OF_WIND_GENERATOR_USING_DOUBLY-FED.ppt

A NON-LINEAR CONTROL ALGORITHM FOR IMPROVING PERFORMANCE OF WIND GENERATOR USING DOUBLY-FED INDUCTION GENERATOR INSTITUTE OF ELECTRICAL POWER ENGINEERING Chair Electric Drives and Basics of Electrical Power Engineering M.Sc. Phung, Ngoc Lan Athens, Feb/Mar.2006 Introduction Conventional control of doubly fed induction machine (DFIM) in wind generator Based on the continuous or discreet model of DFIM Decoupling in active- and reactive power (P S Switch; L Inductor Microcontroller 3 3 PM 3 S DFIM n PM Transformer L Udc UsUn IrIs 5 Demonstration of voltage-, flux- and current vector in d-q coordinator 6 Electrical model of DFIM in d-q coordinator 7 Electrical model of DFIM in state-space - Rotor angular speed: Input variable of the model - Model of DFIM in state-space shows a bilinear system 8 Contents 1.DFIM Model and its characters. 2. Conventional control of DFIM in wind generator 3.Exact-Linearization“ Concept and implemetation with DFIM 4.Control structure with Direct-Decoupling“ 5.Conclusion and prospects 9 Control variables of the active- and reactive power The active power P and reactive power Q will be separately controlled through ird and irq 10 A control structure of DFIM in wind generator 11 Contents 1.DFIM Model and its characters. 2.Conventional control of DFIM in wind generator 3. Exact-Linearization“ Concept and implementation with DFIM 4.Control structure with Direct-Decoupling“ 5.Conclusion and prospects 12 Why do we apply Exact-Linearization“ ? The nonlinear characters of DFIM Exact linearization guarantees not only the linearity between inputs and outputs but also the decoupling between each pair of input and output variable in the new model - noninteracting Performance of system in dynamical operation mode should be improved With the success of exact-linearization, different methods to design controllers for the new linear model could be applied. 13 Exact-Linearization“ the concept (1) Given a nonlinear MIMO-System with m inputs and m outputs then it is able to transfer the system in another state-space, where the linearity between the inputs and outputs is guaranted. Matrix L is invertible when the following conditions are satisfied: Sum of elements of vector of relative degree Number of state variables Relative degree j-th 14 Exact-Linearization“ the concept (2) With a coordinator transformation And with a state feedback controller The new linear system will be A coordinator transformation Requirements of knowing the feedback of state variables The linearity between inputs and outputs is effective in the whole new state-space Notice 15 Exact-Linearization“ Implementation with DFIM Considering three equations of DFIM with, then 16 Exact-Linearization“ Implementation with DFIM (1) The model in state-space will be in form of with By having Sum of elements of vector of relative degree: Relative degree j-th Matrix L is invertible Exact-linearization of the considering system can be implemented with the state feedback controller: 17 Exact-Linearization“ Implementation with DFIM (2) In the new state-space, system will be: In detail: The linearity between inputs and outputs. Decoupling between each channel defined as direct-decoupling The transfer function of the new system consists of only Integration elements The coordinator transformation have only algebraic operations Notice 18 Contents 1.DFIM Model and its characters. 2.Conventional control of DFIM in wind generator 3.Exact-Linearization“ Concept and implementation with DFIM 4. Control structure with Direct-Decoupling“ 5.Conclusion and prospects 19 v Structure of the new linear model 20 Control system of DFIM in wind generator with direct-decoupling 21 Circuit diagram with Plecs 22 Performance of linearized model and current controller Performance of w1, y1 (ird) and w2, y2 (irq) ird irq w1 w2 Performance of current controller ird* & ird irq* & irq 23 Simulation: Grid voltage and electrical torque Grid voltage 50% 75% 100% Torque Linear Control Torque Nonlinear Control 24 Simulation: Active and reactive power P Linear Control P Nonlinear Control Q Linear Control Q Nonlinear Control 25 Simulation: Rotor current ird Linear Control ird Nonlinear Control irq Linear Control irq Nonlinear Control 26 Conclusion and perspectives Control system of DFIM with exact-linearization: practical and easy to implement. The simulation with Matlab/Simulink/Plesc shows good results, the complete con