1
Abstract —The paper presents the dynamic model and control
schemes of a variable speed pitch wind turbine with permanent
magnet synchronous generator (PMSG). The model incl udes a
PMSG model, a pitch-angled controlled wind turbine model and
a drive train model. The drive train model uses one-mass model
to represent the mechanical characteristics of the generator set.
The generator mode
l
is estab
l
ished in the dq–synchronous
rotating reference frame. The wind turbine model detail s the
mechanism of variable speed operation of the turbine by a pitch
control. The control schemes in the paper incl ude a pitch angle
contro
l
for the wind turbine and a speed contro
l
for the
generator. The pitch angle control uses wind speeds and electric
power output as the input signals to ensure normal operation in
high wind speed. The speed contro is rea ized through fie d
orientation where the d-axis current is set to zero and the q-axis
current is used to control the rotational speed of the generator
according to the variation of wind speed. In order to verify the
presented mode
l
and the contro
l
strategy, simu
l
ations with
MATLAB/Simul ink software have been conducted. Simul ation
results prove the validity of the model and the control schemes.
Index Terms — Permanent magnet synchronous generator,
Wind turbine, Vo
l
tage source converter, Speed contro
l
,
Integration
I. I
NTRODUCTION
IT
H
its abundant, inexhaustible potential, its
increasingly competitive cost, and environmental
advantage, wind energy is one of the best technologies
available today to provide a sustainable supply to the world
development. By the end of 2003, the total installed capacity
of the wind turbines has reached as much as 39.234GW and
will exceed 110GW by the year of 2012 [1]. In depth
understanding and investigation of wind energy related
technologies, such as wind power generators, wind farm
integration, grid code and etc., is very meaningful.
In terms of the generators for wind-power application, there
are different concepts in use today. The major distinction
among them is made between fixed speed and variable speed
wind turbine generator concepts. In the early stage of wind
power development, fixed-speed wind turbines and induction
generators were often used in wind farms. But the limitations
of such generators, e.g. low efficiency and poor power quality,
This work was supported in part by National Natural Science Foundation
of China under grant 50577018.
The authors are with the Key Laboratory of Power System Protection and
Dynamic Security Monitoring and Control under Ministry of Education, North
China Electric Power University, Changping 102206, Beijing, P.R.China
(e-mail: routouter@yahoo.com, ligy@ncepu.edu.cn, zhouming@ncepu.edu.cn,
chengyongzhao@ncepu.edu.cn).
adversely influence their further application. With large-scale
exploration and integration of wind sources, variable speed
wind turbine generators, such as doubly fed induction
generators (DFIGs) and permanent magnetic synchronous
generators (PMSGs) are emerging as the preferred technology
[2]. In contrast to their fixed-speed counterparts, the variable
speed generators allow operating wind turbines at the
optimum tip-speed ratio and hence at the optimum power
efficient for a wide wind speed range.
As the penetration of wind power increases, integrating
large wind farms to power grids and the relevant influences on
the host grids needs to be carefully investigated. So, accurate
and reliable model of variable speed wind turbine generators
are urgently needed for power system simulation analysis. The
paper is dedicated to analyzing the complete model of a
variable speed wind turbine with permanent magnet
synchronous generator and developing control schemes for the
wind turbine generator. The modeled system consists of a
PMSG model, a pitch-angled controlled wind turbine model
and a drive train model. The control schemes include a pitch
angle control and a speed control of the generator. The pitch
angle control uses wind speed signals and power output of the
generator as the inputs. The speed control the concept of
vector control is implemented for the speed control of the
generator in the dq-synchronous rotating reference frame. The
field orientation is realized by setting i dref=0. The q-axis
component of the current i
q
controls the rotational speed.
Simulations have been conducted with the software
MATLAB/Simulink to validate the model and the control
schemes.
II. M
ODEL OF
W
IND
T
URBINE WITH
PMSG
Traditionally, a wind turbine with PMSG is connected to
the AC grid through back-to-back full converters. Nowadays,
with the evolution of power electronics, voltage source
converter based HVDC (VSC-HVDC) [3] has been considered
as a feasible solution to integrating wind farms to grids due to
its favorable features [4]. The analysis in the paper is under
the background of VSC-HVDC. The topology of this method
is depicted in Fig.1 where VSC 1 is the machine side power
converter; T 1 is the interface transformer and L1 is the
inductance of the transformer (the resistance of the
transformer is omitted). ug is the output voltage of the power
converter that should be referred to the machine side and f
e
is
the electric frequency that should vary with the variation of
wind speed.
When VSC-H VDC is implemented for wind power
transmission, the machine side power converter (VSC
1
)
Modeling of the Wind Turbine with a Permanent
Magnet Synchronous Generator for Integration
Ming Yin, Student Member, IEEE, Gengyin Li, Member, IEEE, Ming Zhou, Member, IEEE ,
Chengyong Zhao, Member, IEEE
W
1-4244-1298-6/07/$25.00 ?2007 IEEE.