Title: A NONLINEAR CONTROL ALGORITHM FOR IMPROVING PERFORMANCE OF WIND GENERATOR USING DOUBLYFED INDUCTION
1A 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
2Introduction
- 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 (PQ)
control - A voltage dip what happened ?
- A new control scheme !
- Decoupling of PQ is guaranted
- Better performance in dynamical operation mode
- Non-linear control of DFIM with
Exact-Linearization - Current model of DFIM is able to be exactly
linearized ! - A new current controller is with only P-Type
controllers - The complete control structure is simple.
- Decoupling is guaranteed - Direct-Decoupling
3Contents
- DFIM Model and its characters.
- Conventional control of DFIM in wind generator
- Exact-Linearization Concept and
implementation with DFIM - Control structure with Direct-Decoupling
- Conclusion and prospects
4Contents
- DFIM Model and its characters.
- Conventional control of DFIM in wind generator
- Exact-Linearization Concept and
implementation with DFIM - Control structure with Direct-Decoupling
- Conclusion and prospects
5Control system of DFIM in wind generator
6Demonstration of voltage-, flux- and current
vector in d-q coordinator
7Electrical model of DFIM in d-q coordinator
8Electrical model of DFIM in state-space
- Rotor angular speed Input variable of
the model - Model of DFIM in state-space shows a
bilinear system
9Contents
- DFIM Model and its characters.
- Conventional control of DFIM in wind generator
- Exact-Linearization Concept and implemetation
with DFIM - Control structure with Direct-Decoupling
- Conclusion and prospects
10Control variables of the active- and reactive
power
The active power P and reactive power Q will be
separately controlled through ird and irq
11A control structure of DFIM in wind generator
12Contents
- DFIM Model and its characters.
- Conventional control of DFIM in wind generator
- Exact-Linearization Concept and
implementation with DFIM - Control structure with Direct-Decoupling
- Conclusion and prospects
13Why do we apply Exact-Linearization ?
- The nonlinear characters of DFIM
- Performance of system in dynamical operation mode
should be improved
- 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 ---gt noninteracting
- With the success of exact-linearization,
different methods to design controllers for the
new linear model could be applied.
14Exact-Linearization the concept (1)
- Given a nonlinear MIMO-System with m inputs and m
outputs
15Exact-Linearization the concept (2)
- With a coordinator transformation
- And with a state feedback controller
- The new linear system will be
16Exact-Linearization Implementation with DFIM
Considering three equations of DFIM
17Exact-Linearization Implementation with DFIM
(1)
The model in state-space will be in form of
with
18Exact-Linearization Implementation with DFIM
(2)
In the new state-space, system will be
In detail
19Contents
- DFIM Model and its characters.
- Conventional control of DFIM in wind generator
- Exact-Linearization Concept and
implementation with DFIM - Control structure with Direct-Decoupling
- Conclusion and prospects
20Structure of the new linear model
v
21Control system of DFIM in wind generator with
direct-decoupling
22Circuit diagram with Plecs
23Performance of linearized model and current
controller
24Simulation Grid voltage and electrical torque
Grid voltage
100
75
50
Torque Linear Control
Torque Nonlinear Control
25Simulation Active and reactive power
P Linear Control
P Nonlinear Control
Q Linear Control
Q Nonlinear Control
26Simulation Rotor current
ird Linear Control
ird Nonlinear Control
irq Linear Control
irq Nonlinear Control
27Conclusion and perspectives
- Control system of DFIM with exact-linearization
practical and easy to implement.
- Performance of system is improved with the static
direct-decoupling current controller
- The simulation with Matlab/Simulink/Plesc shows
good results, the complete control system is
being verified on experiment rig
- Advanced methods can be used in design process of
controllers
28Thank you for your attention !