Elsevier Editorial System(tm) for Renewable & Sustainable Energy Reviews Manuscript Draft Manuscript Number: Title: Implementing Magnetic Repulsive Force for Continuous Windmill Rotation. Article Type: Review Article Section/Category: Renewable Energy: Education Keywords: KEYWORDS-Bldc motor with permanent magnets, Continuous rotation in windmill, magnetic repulsive force. Corresponding Author: Mr. NAGARAJAN S, M.E Corresponding Author's Institution: ANNA UNIVERSITY,TIRUNELVELI First Author: NAGARAJAN S, M.E Order of Authors: NAGARAJAN S, M.E Abstract: Abstract—wind may not be available continuously throughout the year, the wind power is intermittent. Hence continuous power generation from the wind energy have become a great challenge. As a solution to this problem, we propose a project in which principle of MAGNETIC REPULSIVE FORCE is implemented for continuous windmill rotation. In our proposed system four magnets are arranged around the four pole BLDC motor. Here four magnets are stationary which are fixed diagonally to the BLDC motor. A magnetic field is produced by the BLDC motor. The magnetic field produced by the BLDC motor repels the magnetic field produced by the stationary magnets. Hence a repulsive force is created and the wind mill starts rotating. These magnetic fields cut each other and an EMF is induced. Now the motor acts as a generator. Hence power can be generated even at low wind speed. The analogy values of current and voltage are monitored. KEYWORDS-Bldc motor with permanent magnets, Continuous rotation in windmill, magnetic repulsive force. Suggested Reviewers: sasikumar n srec
[email protected] It's a nicely crafted paper on a very important concept of producing emf and converting a motor into a generator. Conceptually it seems to be true. It may work. But the very obvious questions arises is of its validity on economic terms. The paper is short and interesting. Technically it is a good technology to incorporate with the wind mills but again the point to validate it is that how far this process will remain energy efficient. Introduction and methodology part is quite impressive, brief and clear. Agaim the conclusion of the paper is quite crisp which revolves around the fact that BLDC magnet produces the magnetic field very efficiently and To improve the performance of the windmill paper proposes the concept of repulsive force, which if added
as an integral part of the small wind turbine, can overcome the initial inertia during cut in wind speeds(in the range of 2-4m/s) and be set into rotation using the magnetic repulsive property HEMA s B.E ELECTRICAL, srec
[email protected] As seen from above calculations, if the wind velocity is 10m/s, power up to 150 Watts is produced in an existing windmill of the prior art. But this wind speed is not available at all times. If the wind speed is below 3.5 m/s, the windmill is no longer able to generate power. thangalakshmi B Jerusalem College of Engineering
[email protected] When this is possible, the small turbine instead of consuming aerodynamic force to set a standstill rotor into rotation can actually start producing power at low wind speeds. During the continuous operation of the small wind turbine, this would mean an additional 7-10% extra power extraction for all ranges of wind speed say a wind turbine of rating 1KW that produces 500 watts at 8 m/s, with this system in place can produce up to 550-570 watts . Opposed Reviewers: venu n srec
[email protected] The paper presents a proposal for producing power at low wind speeds by small wind turbine using repulsive force of permanent magnets but in abstract it is mentioned that it is a project proposal.. at places it is a experimental investigation .. but the paper is dis-organized too sketchy and does not present any results .The paper title is misleading as there is no experimental investigation done for power production by wind turbines at low wind speeds as claimed , In abstract it is mentioned that analog values of current and voltage are monitored but no experimental results are presented.
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Implementing Magnetic Repulsive Force for Continuous Windmill Rotation. S.Nagarajan1 Email:
[email protected]
Abstract—wind may not be available continuously throughout the year, the wind power is intermittent. Hence continuous power generation from the wind energy have become a great challenge. As a solution to this problem, we propose a project in which principle of MAGNETIC REPULSIVE FORCE is implemented for continuous windmill rotation. In our proposed system four magnets are arranged around the four pole BLDC motor. Here four magnets are stationary which are fixed diagonally to the BLDC motor. A magnetic field is produced by the BLDC motor. The magnetic field produced by the BLDC motor repels the magnetic field produced by the stationary magnets. Hence a repulsive force is created and the wind mill starts rotating. These magnetic fields cut each other and an EMF is induced. Now the motor acts as a generator. Hence power can be generated even at low wind speed. The analogy values of current and voltage are monitored.
KEYWORDS-Bldc motor with permanent magnets, Continuous rotation in windmill, magnetic repulsive force.
I.INTRODUCTION In the recent years, wind power generators operate in every size that vary between tiny plants for battery charging at isolated residences and up to neargigawatt sized off-shore wind farm that provides electricity to national electrical networks. Because of the continuous power generation requirements from the wind turbines, the design of wind mills becomes a great challenge [1]. As a practical solution to this problem, the principle of magnetic repulsive force is used for continuous windmill rotation. Brushless DC motor is used to create a magnetic field around the four neodymium permanent magnets that are fixed diagonally [3],[7]. As the magnetic fields cut each other an emf is induced that makes the windmill to rotate with finite rpm. Here, the permanent magnets consist of same poles to create the repulsive force as shown in Fig.1 [7]. This conversion in the windmill generates power by the repulsive force even at low wind speeds.
Fig 1. Magnetic repulsive force created by same poles
II.BACKGROUND STUDY . To improve the performance of a windmill, the concept of magnetic repulsive force using BLDC (Brushless Direct Current) motor is proposed as an integral part of a small wind turbine [29]. It provides the initial inertia coupling during the very low wind speeds (about 2- 4 m/sec) and rotates the wind mill through magnetic repulsion. The BLDC motor is able to set a standstill rotor into rotation that actually start producing power even at low wind speeds while the conventional turbine requires an aerodynamic force impulse to initiate the rotation. Through the continuous operation of a small wind turbine with BLDC motor, an additional power extraction about 710% for all ranges of wind speeds can be obtained. For example, a wind turbine of rating 1 KW produces 500 watts at 8 m/s, could produce 550-570 watts while this system is implemented. The additional energy produced by installing such a system can be recouped the expenses spent in 5 years instead of 8 years. The main objective of this paper is to build a windmill which produce electricity continuously even in the absence of wind using repulsive force.
To meet increasing power demand. It can be located even at low wind speed area.
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To provide uninterrupted supply to the customers throughout the year.
BLOCK DIAGRAM OF PROPOSED SYSTEM
In present scenario the power generation from the windmill is less. To overcome the low power production by windmill, the concept of magnetic repulsive force implemented to overcome the initial inertia, during wind speeds and be set into rotation using the magnetic repulsive property. III. PROPOSED SYSTEM In proposed system the BLDC motor is used with four neodymium magnets to produce magnetic repulsive force [27]. Here the BLDC motor act as a generator. The magnetic fields are produced by the four neodymium and the four pole BLDC motor. The BLDC motor poles are align automatically according to the poles of four magnets which are fixed outside of the BLDC motor [16]. The rotor of a 4 pole BLDC motor is made out of permanent magnets [8].
Fig.3. Block diagram of proposed system
The four neodymium permanent magnets are fixed around the BLDC motor. So the magnetic fields are created by the BLDC motor and the four neodymium permanent magnets. The two fields are interact each other and produces the imbalance force. So the blades are rotates [27]. Due to this EMF get induced. Hence the power generated. The voltage and current values are monitored in the PC. ADC are inbuilt with the Microcontroller which converts the analogy values into digital. USB interface is used to transfer the data to the PC [6], [7]. The voltage and current waveform can be predicted using the Lab VIEW software which has benefits over other development environment, has extensive support for accessing instrumentation hardware [7].
Fig 2.Arrangements of magnet with
BLDC motor
IV.HARDWARE MODEL
The two magnetic fields which are produced by both the BLDC motor and the four magnets which are fixed diagonally to the BLDC motor. These magnetic fields are cut each other. Hence the emf induced [8]. So the motor act as a generator. From this generator analog values of current and voltage are monitored. Analog values are converted to digital values by microcontroller. These values are transmitted to the PC through the USB interface [6]. The USB port of the computer is used for communication with microcontroller.
Fig.4.Hardware Model
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V.SIMULATION OUTPUT C = constant = 0.25 to 0.45 K= efficiency factor = 0.0001333 D = Diameter of propeller in m. V = wind speed in m/s.
1 KW = 1.340Hp
Fig.5.Simulation Output 1
Formula to calculate repulsive Force
B₀2A2 (L2+R2) ∏µ₀L2
F=
1 + X2 +
Where, B₀ = Magnetic flux density A = Area of pole (m2) L = Length of magnet (m) Fig.6.Simulation Output
2
R = Radius of each magnet (m) X = Separation between two magnets.
VI.CALCULATION FOR PROPOSED SYSTEM µ₀ = 1.25x106 An exemplary calculation establishing the present invention is presented below. This calculation is based
Relation between Force and Velocity
on a windmill having a tower height between 50m and 70m, blade. Length (L) = 10m and blade diameter (D)
Mv2 r
F=
= 40m to 90m, which are typical windmill dimensions for the application under consideration.
M = mass of the propeller r = radius of the propeller m = 0.1452 x R x 2.9158 (kg)
Formula to calculate power
3
2 Power produced in watts
= CxK x
Dia of windmill propeller
X
Wind speed
1 (x+2L) 2
+
-
2 (x+L) 2
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Power calculation for existing windmill
R = 21.21 cm; Radius of each magnet (m)
(Having the dimensions mentioned above)
X = 60 cm; Separation between two magnets
Tower height = 50m to 70m
∏ = 3.14
Blade length (L) = 10m µ₀ = 1.25 x 10-6
Blade diameter (D) = 40m to 90m Velocity (V) = above 3.5m/s.
PROPOSED WIND TURBINE
P = C x K x D 2 x V3 Assuming
Method to calculate the diagonal distance (D)
C = 0.25 to 0.45
between two magnets:
K = 0.0001333
As the magnets are fixed in a hub in an arrangement
D = 50m
as shown, they make a square formation. Hence the
V = 10m/s,
diagonal distance between two magnets is calculated
P = 0.40 x 0.0001333 x 502 x 103
P = 133.3
by Pythagoras theorem
Watts
Using Pythagoras theorem, D = √302 + 302
If V = 3.5 m/s P = 0.40 x 0.0001333 x 502 x 3.53 P = 5.71
D = 42.42 cm
W
Power calculation for proposed windmill Power calculation in a windmill provided with the
1.232 x 900 x 10-4 (0.32 + 0.21212) F= 3.14 x 1.25 x 10-6 x 0.32
1 1 2 + (0.6+0. 0. (0.6+0. 6)2 62 3)2 +
+
device according to the present invention As mentioned earlier, magnetic repulsive force in utilized in this invention to rotate the wind blades F = 52.03 KN
F=
B₀2A2 (L2+R2) ∏µ₀L2
1 1 2 + (x+L2 X +
+
-
2 (x+L2
mv2 F= R
Assuming F= B₀ = 1.23 T
2 4mv (4 blades in the exemplary windmill) R
RxF 4m
L = 30 cm; Length of magnet (m)
V2 =
B = 30 cm; Breadth of magnet (m)
Substituting m = 0.1452 x R x 2.9158 in this equation,
A = lxb = 900 x 10-4m2; Area of pole (m2)
V2 =
RxF 4(0.1452 x R x 2.9158)
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3
V2 =
25 x 52.03 x 10 4(0.1452 x 25 x 2.9158)
V = 175.28 m/s P = C x K x D 2 x V3 = 0.40 x 0.0001333 x 502 x 175.283
P = 716.22
KW
VII.SUMMARY As seen from above calculations, if the wind velocity is 10m/s, power up to 150 Watts is produced in an existing windmill of the prior art. But this wind speed is not available at all times. If the wind speed is below 3.5 m/s, the windmill is no longer able to generate power. So, magnetic repulsive force is introduced in the present invention to overcome this problem. Due to the large magnetic repulsive force, blades rotate at speeds above 150 m/s. The same windmill is
this system in place can produce up to 550570 watts . 4) This excess production, if calculated over the whole year of operation would mean a small wind turbine of 1 KW can produce anything like 1000-1500 Kw/hr of excess annual energy production which would mean the cost that was spent in installing such a system can be recouped in 5 years instead of 8 years. IX.CONCLUSION To improve the performance of the windmill we have proposed the concept of repulsive force, which is added as an integral part of the small wind turbine, it can overcome the initial inertia during cut in wind speeds(in the range of 2-4m/s) and be set into rotation using the magnetic repulsive property. When this is possible, the small turbine instead of consuming aerodynamic force to set a standstill rotor into rotation can actually start producing power at low wind speeds. During the continuous operation of the small wind turbine, this would mean an additional 710% extra power extraction for all ranges of wind speed say a wind turbine of rating 1KW that produces 500 watts at 8 m/s, with this system in place can produce up to 550-570 watts . This excess production, if calculated over the whole year of operation would mean a small wind turbine of 1 KW can produce anything like 1000-1500 Kw/hr of excess annual energy production which would mean the cost that was spent in installing such a system can be recouped in 5 years instead of 8 years.
enabled to produce power in the ranges of 700 KW as established above. This enables us to produce electricity even at low wind speeds. VIII.ADVANTAGES 1) Using this concept the small wind turbine can overcome the initial inertia during cut in wind speeds (in the range of 2-4m/s) and be set into rotation using the magnetic repulsive property. 2) When this is possible, the small turbine instead of consuming aerodynamic force to set a standstill rotor into rotation can actually start producing power at low wind speeds. 3) During the continuous operation of the small wind turbine, this would mean an additional 7-10% extra power extraction for all ranges of wind speed say a wind turbine of rating 1KW that produces 500 watts at 8 m/s, with
X. Funding source This research received no specific grant from any funding agency in the public, commercial or nonprofit sectors. XI.Conflict of interest The authors declare that there is no conflict of interest. XII.Acknowledgements The authors wish to express their appreciation to MIT, Chennai for providing facilities to carry out the work. Thanks are extended to Dr.J. Bruce Ralphin Rose of wind turbine Research Laboratory,
XIII.REFERENCES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65
[1] Golding.EW: “The Generation of Electricity by Wind Power”. Redwood Burn Limited, Trowbridge, 1976. [2] Lysen.EH: “Introduction to Wind Energy, basic and advanced introduction to wind energy with emphasis on water pumping windmills”. SWD, Netherlands, 1982.
[15] R.Krishnan. “A Text Book on Electric Motor Drives, Modelling, Analysis and Control”. Prentice Hall of India Pvt Ltd., New Delhi. [16] Q.Wang and L.C. Chang, “An intelligent maximum power extraction algorithm for inverter-based variable speed wind turbine systems,” IEEE Trans. Power Electron., vol. 19, no. 5, pp. 1242– 1249, 2004.
Windpumping
[17] Lysen. EH: “Introduction to Wind Energy, basic and advanced introduction to wind energy with emphasis on water pumping windmills”. SWD, Netherlands, 1982.
[4] David, A. Spera: Wind Turbine Technology, fundamental concepts of wind turbine engineering. ASME Press, 1994.
[18] Lancashire.S, Kenna.J and Fraenkel.P, Wind pumping Handbook, IT Publications, London, 1987.
[5] Hugh Piggot: Windpower Workshop, building your own wind turbine.Centre for Alternative Technology, 1997.
[19] David, A. Spera, Wind Turbine Technology, fundamental concepts of wind turbine engineering. ASME Press, 1994.
[6] S. Dunnett: Small Wind Energy Systems for Battery Charging.Practical Action Technical Information Leaflet,Hugh Piggott: It’s A Breeze, A Guide to Choosing Windpower.Centre for Alternative Technology, 1998.
[20] Hugh Piggot: Wind power Workshop, building your own wind turbine, Centre for Alternative Technology, 1997.
[3] Lancashire.S, Kenna.J and Fraenkel.P: Handbook.I T Publications, London, 1987.
[7] Paul Gipe: Wind Energy Basics, a guide to small and micro wind systems.Chelsea Green Publishing Company, 1999. [8] E. Koutroulis and K. Kalaitzakis, “Design of a maximum power tracking system for wind-energy-conversion applications,” IEEE Trans. Ind. Electron., vol. 53, no. 2, pp. 486–494, Apr. 2006. [9] R.Datta and V.T Ranganathan, “A method of tracking the peak power points for a variable speed wind energy conversion system,” IEEE Trans. Energy Convers., vol. 18, no. 1, pp. 163–168, Mar. 2009. [10] P.C.K. Luk and C.K. Lee, “Efficient modeling for a brushless DC motor Drive”. 20th International conference on Industrial Electronics Control and Instrumentation, IECON'94, vol.1, pp. 188191, 1994. [11] A.Sathyan, N. Milivojevic, Y. J. Lee, M. Krishnamurthy, and A.Emadi, “An FPGA-based novel digital PWM control scheme for BLDC motor drives,” IEEE Trans. Ind. Electron., vol. 56, no. 8, pp. 3040–3049, 2009. [12] S.O. Atef, and Al-Mashakbeh, “Proportional Integral and derivative control of brushless DC motor.” Eur. J. Sci. Res., vol. 35, no. 2, pp. 198-203, 2009. [13] R. Byoung-Kuk, K. Tae-Hyung and J. Mehrdad Ehsani, “On the feasibility of four-switch three phase BLDC motor drives for low cost commercial applications topology and control”. IEEE Tran. Power Electron, APEC, vol.18, no. 1, pp. 428-433, 2001. [14] R.Krishnan, and L. Shiyoung, “PM brushless DC motor drive with a new power-converter topology”. IEEE Tran. Indus. Appl., vol. 33, no. 4, pp. 973-982, 1997 .
[21] S. Dunnett: Small Wind Energy Systems for Battery Charging. Practical Action Technical Information Leaflet, Hugh Piggott: It’s A Breeze, A Guide to Choosing Wind power. Centre for Alternative Technology, 1998. [22] Paul Gipe, Wind Energy Basics, a guide to small and micro wind systems, Chelsea Green Publishing Company, 1999. [23] T. Anderson, A. Doig, D. Rees and S. Khennas, Rural Energy Services - A handbook for sustainable energy development. ITDG Publishing, [24] “An electromagnetic energy harvesting device based on high efficiency windmill structure for wireless forest fire monitoring application”- ELSEVIER Xiao Wang, Cheng Liang Pan∗, Yong Bin Liu, Zhi Hua Feng et.al (2015) [25] R.N. Sharma, U.K. Madawala et.al (2011) “The concept of a smart wind turbine system”- ELSEVIER. [26] Minu John, Syamily P.S, Vyshak et.al (2014) “Maglev windmill”-IEEE. [27] Giuseppe Buja, Manuele Bertoluzzo et.al (2015) “Torque ripple-free operation of PM BLDC drives with petal-wave current supply”-IEEE. [28] Tae-Jin Kang, et.al (2013) “Numerical Investigation of Active Control for an S809 Wind Turbine Airfoil”- ELSEVIER. [29] Saeed Masoumi Kazraji*‡, Saheb Khanabdal*, Ramin Bavil Soflayi*, Mehran Sabahi (2014) “A micro scale wind turbine fed BLDC for electric vehicle drive application”-IJET. [30] Adam Chehouri, Rafic Younes, Adrian Ilinca, Jean Perron, et.al (2012) “Review of performance optimization techniques applied to wind turbines”- ELSEVIER
