Environmental Engineering Reference
In-Depth Information
s
c
Generator torque control
x
g
Generator speed
x
g
Filtered generator speed
x
ng
Rated generator speed
P
e
Electrical power
P
ref
Reference power
h
Scheduling parameter
x
Denotes dx/dt
15.1 Introduction
With wind turbines becoming larger and more flexible, the control system has
become extremely important and so has a testing environment for the control
system itself. A comprehensive assessment of WT controllers in the lab reduces
risks of erroneous implementations in the field and significantly shortens com-
missioning times.
Following the lead of the auto industry, the WT industry has begun moving
toward adoption of hardware-in-the-loop (HIL) simulation as a method for real-
time testing of embedded control systems during the development phase without
using prototypes. On the contrary of computer simulation, HIL simulation uses one
or several actual components instead of their simulation model. The other parts of
the process are simulated [
7
]. Such a methodology has been used in aeronautics for
a long time [
12
]. Traction applications are nowadays more and more developed
using HIL simulation before the final implementation [
14
,
17
]. HIL tests are
essential for fast and cost-effective commissioning of controllers in the field (or at
sea in the case of offshore wind farms). A major benefit of doing these simulations
is that it allows design engineers to optimize the control system during the
development stage, which is going to have a big impact on reliability. Moreover,
engineers can take exactly the same code that was used in the simulation and run it
directly on the deployed target, saving time and effort in the design process.
Finally, the controllers must be tested in extreme cases, such as faults on sensors
an/or actuators of the WT. However, testing these cases experimentally can seri-
ously damage the WT, thus a HIL approach is preferable.
To this end, a HIL test setup for WT controllers is developed in this chapter.
The torque controller and the communication system can be integrated as hard-
ware in a real-time simulator, which models the behavior of the WT. The HIL
proposed platform is used to characterize the behavior of the WT in region 3 in
normal operation as well as in fault operation. In particular, a stuck/unstuck fault is
modeled and the behavior of a proposed chattering torque controller is analyzed in
comparison to a baseline torque controller.
