Control analysis of the wind turbine with transmission
to split power
T Zhang
1
,WLi
2
, and YDu
3
1
Jiangsu University, Zhenjiang, People’s Republic of China
2
Department of Mechanical Engineering, Institution of Construction and Propulsion Engineering, Chemnitz University
of Technology, Chemnitz, Germany
3
CAE-Methods Volkswagen AG, Wolfsburg, Germany
The manuscript was received on 24 April 2005 and was accepted after revision for publication on 6 January 2006.
DOI: 10.1243/09576509JPE187
Abstract: In this article, a wind turbine with power splitting transmission, which is realized
through a three-shaft planetary gearbox, is presented. The input shaft of the transmission is
driven by the rotor of the wind turbine, the output shaft is connected to the grid via the main
generator (asynchronous generator), and the third shaft is driven by a control motor with
variable speed. The dynamic models of the subsystems of this wind turbine, e.g. the rotor aero-
dynamics, the drive train dynamics, and the power generation unit dynamics, were given and
linearized at an operating point. These submodels were integrated in a multi-disciplinary
dynamic model, which is suitable for control syntheses to optimize the utilization of wind
energy and to reduce the excessive dynamic loads. The important dynamic behaviours were
investigated and the suggestions to design a suitable control system were given.
Keywords: variable speed wind turbine, renew energy, mechatronic control model, power
splitting transmission
1 INTRODUCTION
The power generation with wind turbines has grown
during the past 20 years. The customers who are
environmentally conscious have now been using
this clean wind energy from power providers. The
global market for the electrical power produced by
the wind turbine generator has been increasing stea-
dily, which directly pushes the wind power techno-
logy into a more competitive area [1]. However, in
recent years, many wind turbines were incapacitated
because of the damage caused by excessively high
dynamic loads from the strong fluctuations of the
wind speed. Several solutions have been presented
to reduce the dynamic loads and to utilize the wind
energy more effectively. To reduce the dynamic
loads, wind turbines, which use the asynchronous
generator at constant rotor speed, were discussed
in reference [2]. Later, the wind turbines at variable
speeds are investigated by many researchers [3–8].
There are two important structures for the variable
speed wind turbines. The first structure consists of
a fixed ratio transmission and a variable speed gene-
rator. The generator is usually connected to the elec-
trical supply system through a rectifier and an
inverter. The main disadvantages of these solutions
are the high cost of electronic hardware, off-setting
the main objectives of increased cost-effectiveness,
a loss of 5–10 per cent in the energy output caused
by the rectification and inversion of all generated
power, and the harmonics generated by the elec-
tronic conversion induce electrical noise in the elec-
trical grid [5]. To overcome these disadvantages, a
new transmission technology was applied, which
splits the power into the main induction generator
and a control motor. By adjusting the torque of the
control motor, the speed of the main induction
generator can be always run at a desired constant
speed to maximize the capture of the wind energy,
although wind speeds are strongly variable. This
Corresponding author: Department of Mechanical Engineering,
Institution of Construction and Propulsion Engineering,
Chemnitz University of Technology, Reichenhainer Str. 70, Zi. A 317,
Chemnitz 09126, Germany. email: wenyong.li@mb.tu-chemnitz.de
415
JPE187
#
IMechE 2006 Proc. IMechE Vol. 220 Part A: J. Power and Energy