International Journal of
Emerging Research in Management &Technology
ISSN: 2278-9359 (Volume-3, Issue-7)
Research Article
July
2014
Modelling and Simulation of Permanent Magnet Synchronous
Motoer Based Wind Energy Conversion System
Neeraj Pareta
Electrcial Engineering & PAHER
India
Naveen Sen
Electrical Engineeering &PAHER
India
Abstract—
This Paper describes about the wind power and its potential that can be harnessed in the future to meet the current
energy demand. With detailed description of the wind turbine and the wind generator focus has been given on the
interconnection of the generators with the grid and the problems associated with it. The use of power electronics the
circuitry and their applications have also been emphasized. In the end a voltage stability analysis has been done with
respect to various models of the wind turbines to find the best way to clear faults and have optimum output. Generic
three-phase AC-DC-AC converter, converter control methods for wind power generation, wind turbine, two mass drive
train and PMSG generator are modelled in the thesis using MATLAB/SIMULINK for establishing variable-speed
wind energy conversion systems.
The developed wind energy conversion system have been validated through simulation study using
MATLAB/SIMULINK, under different input/output conditions like constant wind speed, variable wind speed, and
different fault conditions. The simulation results verify the validity of the developed wind energy conversion system
and its controls.
Keywords—PSMG, WECS , FPGA , DPC ,SCIG
I.
INTRODUCTION
In the recent years, awareness about global warming and the harmful effect of carbon emission is significantly increased
among the people and researchers as well. So that clean and substantial energy sources like Wind, Sea, Sun, Biomass etc.
comes into higher demand. Among all these, Wind energy has experienced the highest growth in last 10 years. This is
just because wind energy is a pollution free resource which has inexhaustible potential and also delivering the
competitive cost advantage over others.
The main drawback of Wind is its irregularity in occurrence and how to maximize the energy generation from wind. The
wind energy can be harnessed by a wind energy conversion system (WECS), composed of a wind turbine, an electric
generator, a power electronic converter and the corresponding control system. Various WECS structures could be
realized from the several categories of available components. However, the main objective of every structure is same that
is conversion of Wind energy at varying wind velocities into the grid frequency of electricity.
With special reference to the speed, two main classes are recognized for the generators of wind power application that are
constant and variable speed generators. The constant speed wind turbines and induction generators were often used, in
the early stages of wind power development. Some of the disadvantages of fixed speed generators are the low
efficiencies, poor power quality, high mechanical stress including a runtime issue that is maximum coefficient of
performance could obtained only at a particular Wind speed. Now a days variable speed operations became more
attractive because of the development of power electronics and falling cost of component and technology as well [3]. By
running the wind turbine generator in variable speed, variable frequency mode, and the maximum power could be
extracted at low and medium wind speeds. Among all kinds of wind energy conversion systems (WECSs), a variable
speed wind turbine (WT) equipped with a multi pole permanent magnet synchronous generator (PMSG) is found to very
attractive and suitable for the application in large wind farms. With gearless construction of such PMSG, advantages like
low maintenance, reduced losses and costs, high efficiency and good controllability could be derived[5]. At present, the
PMSG-based WECS has been commercialized by some WT manufactures, such as Siemens Power Generation and GE
Energy. The objective of this work is to develop and implement an AC-DC-AC PWM converter based wind energy
conversion system (WECS) in MATLAB/SIMULINK. The various objectives of the work are:
1. To study the complete system of WECS, develop mathematical model of various components PMSG, ACDC-AC converter, wind turbine, pitch controller and two mass drive train of the wind energy conversion
system (WECS).
2. To implement proposed wind energy conversion system (WECS) using MATLAB/SIMULINK.
3. To investigate the input/output condition of develop wind energy system for different case like constant,
dynamic and faulty observation.
II.
DIFFERENT GENERATOR BASED WIND ENERGY CONVERSION SYSTEM (WECS)
A structure of Wind Energy Conversion System (WECS) is assembled with several components like blades, an electric
generator, a power electronic convertor and control system. The WECS can be categorized into converting the wind
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First Author et al., International Journal of Emerging Research in Management &Technology
ISSN: 2278-9359 (Volume-3, Issue-7)
kinetic energy into electric power and injecting this electric power into the electrical load or utility grid, but the
functional objectives of these systems would always be same.
Another modification was made in wind turbine designs of traditional asynchronous generator, while other manufacturers
have used doubly–fed asynchronous generators. New electrical converters and control method were developed and tested.
Electrical developments include using advanced power electronics in the wind generation system design, and introducing
the new concept, namely variable speed. Due to rapid advancement of power electronics, offering both higher power
handling capability and power price/KW, the application of power electronics in wind turbines is expected to increase
further. Also, some control methods were developed for big turbines with variable-pitch blades in order to control the
speed of the turbine shaft. The pitch control concept has been applied during the last fourteen years.
Specifically, using variable-speed approach increases the energy output up to 20% in a typical wind turbine system. In
order to perform speed control of the turbine shaft, in an attempt to achieve maximum power, different control methods
such as field-oriented control and constant voltage/frequency (V/f) have been used.
Classification of Wind Turbine Rotors
Wind turbines are usually classified into two categories, according to the orientation of the axis of rotation with respect to
the direction of wind,
 Horizontal-axis turbines.
 Vertical-axis turbines
Horizontal Axis Wind Turbines
Fig.1: Horizontal axis wind turbine
Horizontal-axis wind turbines (HAWT) have the main rotor shaft and electrical generator at the top of a tower, and must
be pointed into the wind. Most of turbines have a gearbox, which turns the slow rotation of the blades into a quicker
rotation that is more suitable to drive an electrical generator.
 Since a tower produces turbulence behind it, the turbine is usually pointed upwind of the tower. Turbine blades are
stiff, which prevents the blades from being pushed into the tower by high winds. Additionally, the blades are placed
at a considerable distance in front of the tower and are sometimes tilted up a small amount.
 Downwind machines have been built, despite the problem of turbulence, because they don't need an additional
mechanism for keeping them in line with the wind, and because in high wind.
 Most of HAWTs are upwind machines. Since (that is repetitive) turbulence may lead to fatigue failures most
HAWTs are upwind machines.
Vertical Axis Wind Turbines
In vertical-axis wind turbines (VAWTs) main rotor shaft is arranged vertically. The key advantage of this arrangement is
that the turbine does not need to be pointed into the wind to be effective, which is an advantageous factor for the sites
where the wind direction is highly variable. VAWTs can utilize winds from varying directions.
Rotor diameter
Fig.2 : Vertical axis wind turbine
With a vertical axis, the generator and gearbox can be placed near the ground, so the tower doesn't need to support it, and
it is more accessible for maintenance. Apart of these advantages some drawbacks are there that some designs produce
pulsating torque; drag may be created when the blade rotates into the wind.
Common Generator Types in Wind Turbine
Several categories of generators are being used by Wind turbines. Modern wind turbine systems use three phase AC
generators. The common types of AC generator that are possible candidates of modern turbine system are as follows:
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




First Author et al., International Journal of Emerging Research in Management &Technology
ISSN: 2278-9359 (Volume-3, Issue-7)
Squirrel-cage rotor induction Generator (SCIG).
Wound –rotor induction Generator (WRIG).
Doubly-Fed induction Generator (DFIG).
Synchronous Generator(with external field excitation),and
Permanent Magnet Synchronous Generator (PMSG).
III.MODELLING OF THE WIND ENERGY CONVERSION SYSTEM
In this , various design and modelling aspects of different components of the Wind Energy Conversion System like
the basic models of synchronous generator, AC-DC-AC PWM converter, wind turbine, drive train and their control
system are described.
The Proposed Wind Energy Conversion System
Fig. 3 : Proposed Wind Energy Conversion System
The proposed WECS system consists of wind turbine, two mass drive train, permanent magnet synchronous machine
(PMSM) which is torque controlled and AC-DC-AC PWM converter.
Permanent Magnet Synchronous Generator (PMSG)
The PMSG is a Synchronous Machine, where the DC excitation circuit is replaced by permanent magnets, by eliminating
the brushes. PMSG has a smaller physical size, a low moment of inertia which means a higher reliability and power
density per volume ratio as it has permanent magnets instead of brushes and the slip rings. Also by having permanent
magnets in the rotor circuit, the electrical losses in the rotor are eliminated. The PMSG are becoming an interesting
solution for wind turbine applications.[1]
However, the disadvantages of the permanent magnet excitation are high costs for permanent magnet materials and a
fixed excitation, which cannot be changed according to the operational point.
The PMSG can be classified according to the rotor configuration:
 Interior magnet type (IPMSG) for this configuration, the magnets is buried inside the rotor. The interior magnet
PMSG usually presents magnetic saliency. The d-axis inductance is smaller than the q-axis inductance (Ld < Lq),
because the effective air gap of the d-axis is bigger than the q-axis air gap. This results in a component of
reluctance torque in addition to the torque produced by the magnet. Because of this, the rotor position is much
easier to detect.
 Surface mounted magnet type (SPMSG) The SPMSG has the magnets mounted on the surface of the rotor. As
the permeability of the permanent magnets is approximately equal to 1, permanent magnets act like air in
magnetic circuits. This means that the air gap is very large and constant. The d- and q-axis inductances are
nearly identical and thsaliency ratio (= Lq/Ld) is 1. Therefore no reluctance torque occurs.
One advantage of the SPMSG is that the surface mounted magnets lead to a very simple rotor design with a low weight.
The parameters of the machine are presented in Table 1
Table1: PMSM Parameters
Parameter
Symbol
Value
Unit
No. of poles
P
6
-
Frequency
F
87.5
[Hz]
Stator resistance
Rs
1.906
[]
d-axis stator inductance
Ld
30.31
[mH]
q-axis stator inductance
Lq
38.36
[mH]
Voltage constant
Ke
495,3
-
Moment of inertia
J
0.002
[kg·m2]
Viscous friction
B
0.0028
The electrical parameters presented in Table 1 were read from the machine plate. The mechanical parameters, moment of
inertia, J, and viscous friction, B, were measured. The measurements are described.
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First Author et al., International Journal of Emerging Research in Management &Technology
ISSN: 2278-9359 (Volume-3, Issue-7)
IV.IMPLENTATION OF WIND ENERGY CONVERSION SYSTEM IN MATLAB/SIMULINK
In this various components of the wind energy conversion system (WECS) like synchronous generator, AC-DC-AC
PWM converter, wind turbine, drive train and their control system is implemented in MATLAB/SIMULINK
environment.
Proposed AC-DC-AC PWM Converter Based WECS Model
Fig. 4: Proposed wind energy conversion system
In order to study the effects of the entire WECS, the proposed system is modelled using MATLAB/SIMULINK
environment by using different toolboxes. It includes a wind turbine and drive train model, PMSG model, and AC-DCAC PWM converter and its control model. The different block sets of SIMPOWER SYSTEM toolbox is specially used to
design the electrical model. System performance under various balanced /unbalanced and various wind conditions have
been investigated which is presented in next chapter. The proposed WECS system as shown in fig. 4 is implemented using
MATLAB/SIMULINK environment as shown in fig. 5.
Fig.5: Proposed wind energy conversion system in MATLAB/SIMULINK
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First Author et al., International Journal of Emerging Research in Management &Technology
ISSN: 2278-9359 (Volume-3, Issue-7)
Wind Turbine Model
The wind turbine model designed in MATLAB/SIMULINK . This block implements a variable pitch wind turbine
model. The performance coefficient Cp of the turbine is the mechanical output power of the turbine divided by wind
power and a function of wind speed, rotational speed, and pitch angle (beta). Cp reaches its maximum value at zero betas.
The wind-turbine power characteristics display the turbine characteristics at the specified pitch angle.
The first input is the generator speed in per unit of the generator base speed. For a synchronous generator, the base speed
is the synchronous speed. For a permanent-magnet generator, the base speed is defined as the speed producing nominal
voltage at no load. The second input is the blade pitch angle (beta) in degrees. The third input is the wind speed in m/s as
shown. The output is the torque applied to the generator shaft in per unit of the generator ratings.
Various parameters of the wind turbine are designed as:
Nominal mechanical output power (W): 8.5e3
Base power of the electrical generator (VA): 8.5e3/0.9
Base wind speed (m/s): 8
Maximum power at base wind speed (p.u. of nominal mechanical power): 0.8
Base rotational speed (p.u. of base generator speed): 1
Fig.6: Wind turbine model
Two Mass Drive Train Model
Fig.7: Two mass drive train model
The Two mass drive train model implemented in SIMULINK is shown in fig. 7.This is turbine and shaft coupling
system. The above subsystem will give shaft torque T_ shaft(pu), W_wt as outputs and T_wt(pu),generator speed(per
unit) as input .It is an example of closed loop control system where feedback is provided just before the gain (=1). The
input will be amplified by gain then it will be multiplied by given transfer function. Ultimately giving W_w t as the first
output whose result could also be seen in scope. Here as shown in fig. 7 before the second sum (middle) block is
displaying the turbine and after it is the shaft. Shaft will have generator speed as an input, going through the same kind of
process as that of T_wt with further amplification by an amount 0.3 gain. Again it is compared with the original input
before giving its final output T_shaft.
V. CONCLUSIONS
In this work, a variable speed wind energy conversion system (WECS) has been developed using
MATLAB/SIMULINK. Mathematical model of various components of the WECS like wind turbine, two mass drive
© 2014, IJERMT All Rights Reserved
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First Author et al., International Journal of Emerging Research in Management &Technology
ISSN: 2278-9359 (Volume-3, Issue-7)
train, PMSG generator, and AC-DC-AC converter along with their controls has been discussed and developed. The
energy extracted from wind is transferred from the generator to the dc-link by the generator-side rectifier and then to the
utility by the grid side inverter.[4]
 The dc-link capacitor provides decoupling between the generator-side and grid-side converter, a thereby offers
separate control flexibilities for the power converters.
 The developed model and its control was simulated in MATLAB/SIMULINK and tested/validated for different
conditions i.e. constant and variable wind speed, different faults like three phase to ground etc.
 The results presented showed good performances of the developed model and control.
Fig. 8: Constant Input wind Speed
Fig. 9: Waveform of synchronous generator rotor wind speed Wm (rad/sec), mechanical torque (Tm), electromagnetic
torque (Te)
Fig. 10: Waveform of three phase output grid voltage and current
Fig. 11: Torque (Tm and Te), rotor speed and the pitch angle
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First Author et al., International Journal of Emerging Research in Management &Technology
ISSN: 2278-9359 (Volume-3, Issue-7)
Fig. 12: Instantaneous active and reactive power waveforms
Fig. 13: Step change in Input wind Speed
Fig 14 shows that waveform of three phase output grid voltage and current are sinusoidal nature
Fig. 15: Waveform of three phase output grid voltage and current
Fig. 16 Torque (Tm and Te), rotor speed and the pitch angle
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First Author et al., International Journal of Emerging Research in Management &Technology
ISSN: 2278-9359 (Volume-3, Issue-7)
Fig. 17 Instantaneous active and reactive power waveforms
After the fault has cleared, various parameters regain their steady state values within short time, indicating the fastness
of the control action.
Fig. 18: Waveform of synchronous generator, rotor wind speed Wm (rad/sec), pitch angle, mechanical Torque (Tm),
electromagnetic torque (Te)
Fig.19 Waveform of dc link voltage, Inverter output ac voltage, line to line grid voltage, and modulation Index
Fig. 20: Waveform of three phase output grid voltage and current
Fig. 21 Instantaneous active and reactive power waveforms
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First Author et al., International Journal of Emerging Research in Management &Technology
ISSN: 2278-9359 (Volume-3, Issue-7)
Fig. 22 Waveform of synchronous generator, rotor wind speed Wm (rad/sec), pitch angle, mechanical torque (Tm),
electromagnetic torque (Te)
Fig. 23 Waveform of three phase output grid voltage and current
Fig.24: Instantaneous active and reactive power waveform
ACKNOWLEDGMENT
I am deeply indebted to Pacific University for giving me an opportunity to work on ―MODELING AND
SIMULATION OF PERMANENT MAGNET SYNCHRONOUS MOTOER BASED WIND ENERGY
CONVERSION SYSTEM‖ and also for their invaluable guidance and patience with me. I would like to thank Principal
FOE Prof T.A.Qazi for his valuable suggestions.
I profusely thank Mr. .Naveen Sen. Head, Department of electrical & Engineering, Faculty of Engineering, Pacific
University (PAHER), Udaipur for providing me all the facilities and the very best technical and support infrastructure to
carry on my work.
I would like to thank Naveen Sen (Advisor) for his support and cooperation in preparing the thesis topic of research
and guiding me. I thank him again for the valuable inputs and providing me his valuable time for starting the thesis work.
I would like to thank all the user and Colleagues who extended help directly or indirectly during my thesis. I
acknowledge the effort of those who have contributed significantly to my thesis and last but not the least I would like to
thank all my M. Tech friends for their continuous support and cooperation. I would like to take this opportunity to
express my profound sense of gratitude and respect to all those who helped me throughout the duration of this work.
REFERENCES
[1] Pahlevaninezhad, M., Eren, S., Bakhshai, A. and Jain,―A model reference adaptive controller for a wind energy
conversion system based on a permanent magnet synchronous generator fed by a matrix converter,‖ In proceedings
of 35th annual conference of the IEEE Industrial Electronics Society, pp.65-70,2010.
[2] Yang, A.G. and Li, B.H., ―Application of a matrix converter for PMSG wind turbine generation system.‖ In
proceedings of 2nd IEEE International Symposium on Power Electronics for Distributed Generation Systems , pp.
619-623,2010.
[3] Haque, M.E., Negnevitsky, M. and Muttaqi, K.M.,“A novel control strategy for a variable-speed wind turbine with
a permanent-magnet synchronous generator,‖ IEEE Transactions on Industry Applications, , vol. 46, no. 1, pp. 331339, Jan/Feb. 2010.
© 2014, IJERMT All Rights Reserved
Page | 51
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
First Author et al., International Journal of Emerging Research in Management &Technology
ISSN: 2278-9359 (Volume-3, Issue-7)
Zhang, S., Tseng, K.J., Vilathgamuwa, D.M., Nguyen, T.D. and Wang, X.Y. , ― Design of a robust grid interface
system for PMSG-based wind turbine generators,‖ IEEE Transactions on Industrial Electronics, vol. 58, no. 1, pp.
316-328, Jan. 2011.
Kumar, V., Joshi, R.R. and Bansal, R.C., ―Optimal control of matrix converter based WECS for performance
enhancement and efficiency optimization,‖ IEEE Transaction of Energy Conversion, vol. 24, no. 1, pp. 264-273,
March. 2009.
Bhende, C.N., Mishra, S. and Malla, S.G., ―Permanent magnet synchronous generator-based standalone wind
energy supply system,‖ IEEE Transactions on Sustainable Energy, vol. 2, no. 4, pp. 361-373, Oct. 2011.
Wang, J., Xu, D., Wu, B. and Luo, Z., ― low-cost rectifier topology for variable-speed high-power PMSG wind
turbines,‖ IEEE Transactions on Power Electronics, vol. 26, no. 8, pp. 2192-2200, Aug. 2011.
Li, S., Haskew, T.A. Swatloski, R.P. and Gathings, W. , ―Optimal and direct-current vector control of direct-driven
PMSG wind turbines,‖ IEEE Transactions on Power Electronics, vol. 27, no. 5, pp. 2325-2337, May. 2012.
Xia, Y., Ahmed, K.H. and Williams, B.W. ― A New Maximum Power Point Tracking Technique for Permanent
Magnet Synchronous Generator Based Wind Energy Conversion System,‖ IEEE Transactions on Power
Electronics, vol. 26, no. 12, pp. 3609-3620, Dec. 2011.
Kazmi, S. M.R., Goto, H., Guo, H. J. and Ichinokura, O. , ― A novel algorithm for fast and efficient speedsensorless maximum power point tracking in wind energy conversion systems,‖ IEEE Transactions on Industrial
Electronics, vol. 58, no. 1, pp. 29-36, Jan. 2011.
Ni, B. and Sourkounis, C., ―Energy yield and power fluctuation of different control methods for wind energy
converters,‖ IEEE Transactions on Industry Applications, vol. 47, no. 3, pp. 1480-1486, May/June. 2011.
Van-Tung Phan, and Hong-Hee Lee, ―Performance enhancement of stand-alone DFIG
systems with control of
rotor and load side converters using resonant controllers,‖ IEEE Trans. On Industry Applications, vol. 48, no. 1,
pp.199-210, Jan. 2012.
Jin Yang, John E. Fletcher,and John OReilly, ―A series-dynamic-resistor-based
converter protection scheme for
doubly-fed induction generator during various fault conditions,‖ IEEE Trans. ON ENERGY Convers., vol. 25, no. 2,
pp. 422-432, Jun. 2010.
Sheng Hu, Xinchun Lin, Yong Kang ,and Xudong Zou , ―An improved low-voltage ride-through control strategy of
doubly fed induction generator during grid fault,‖IEEE Trans. On Power Electronics, vol. 26, no. 12, pp. 36533665, Dec. 2011.
© 2014, IJERMT All Rights Reserved
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