Use of Wind Turbine to Generate Electricity for Household Purposes

Transcription

1 Use of Wind Turbine to Generate Electricity for Household Purposes Kamaljyoti Talukdar Assistant Professor Department of Mechanical Engineering Bineswar Brahma Engineering College, Kokrajhar ABSTRACT: Wind turbines can be used for generating electricity for running household appliances. The wind speed is taken for Kolkata city located in India to study for minimum and maximum wind speed. The minimum wind speed is obtained in the month of October and maximum wind speed is obtained in the month of May. The wind rotates the rotor blades and generates power. This power is transmitted to gear box.the power obtained in gear box is transmitted to the shaft of DC (direct current) generator and from DC generator emf is generated to run various appliances such as 3 fans, 4 lights, 1 refrigerator and 1 pump of 65W,100W,2000Wand 2000W respectively after converting into AC(alternating current) by inverter. The excess current is sent to battery for storage. Keywords: AC, battery, DC, emf, inverter INTRODUCTION Wind energy can be used for various purposes such as grinding grains, water lifting, generating electricity etc. The discussion in this paper is limited to generating electricity. Morren and Haan[1] considered the shortcircuit behavior, especially the short-circuit current of wind turbines with a doubly fed induction generator. Shuhui et al[2] investigated both the conventional and a novel vector control mechanism for a PMSG(permanent magnet synchronous generators) wind turbine that had two side-by-side voltage source pulse width modulation converters. The proposed approach was based on a direct-current vector control mechanism for control of both machine and grid-side converters of a PMSG wind turbine. Timbus et al[3] discussed the evaluation of different current controllers employed for grid-connected distributed power generation systems having variable input power, such as wind turbines and photovoltaic systems. The focus was mainly set on linear controllers such as proportional-integral, proportional-resonant, and deadbeat (DB) controllers. Additionally, an improved DB controller robust against grid impedance variation was also presented. Shuhui et al[4] used data collected at Central and South West Services Fort Davis wind farm (USA) to develop a neural network based prediction of power produced by each wind turbine. Erlich et al[5] dealt with modeling of the doubly-fed induction generator ( DFIG) and the corresponding converter for stability studies. SYSTEM LAYOUT Wind rotates the rotor blades and the power generated by rotor blades is transmitted to rotor shaft. The rotor shaft is connected to gear box and this gear box rotates the shaft connected to the DC generator. The power generated is used for generating current(i g) and voltage by DC generator. A portion of current(i h) is sent to inverter after passing through charge controller for running appliances of a house shown in table 1 and converted into AC(I IH) by inverter and excess current(i b) is sent to battery after passing through charge controller. The wind speed for the month of October and May are used for studying the various parameters. 791 Kamaljyoti Talukdar

2 Fig.1:System layout of wind turbine for supplying electricity to house and battery at particular wind speed Table 1. Specifications of appliances of house No. of appliances No. of items Appliances Power rating(w) 3 Fans 65 4 Lights Refrigerator Pump 2000 Power factor considered 792 Kamaljyoti Talukdar Table 2.Current used by different appliances Voltage of appliances(v) Current used by each appliance(a) Total current(a) 3 fans lights refrigerator pump Total current required by all equipments:

3 Table 3. Efficiencies of various equipments Equipments Efficiency Rotor blades 0.48[6] Gear box(spur gear type) 0.95[7] DC generator 0.9 Charge controller 0.85[8] Inverter 0.85 Battery 0.9[8] GOVERNING EQUATIONS Wind speed (V) at particular height(h) is given by[9]: V V ref H H ref Where V ref-velocity at 1 m height [10],H ref-1m,0.142-factor for flat grassy areas (with low grass height),h- 25m Power(P) developed by wind by a wind blade[11]: P 0.5 AV 3 Where r-density of air at average temperature of air(30.25 o C for October and o C for May)[12]and pressure of bar,a-area of wind blade( m 2,where rotor diameter is 5 m) Total power(p t): No. of wind rotor blades x P (3) Where, No. of wind rotor blades=3 Power transmitted to rotor shaft (P T)=P t x 0.48 (4) Where 0.48-efficiency of rotor Power transmitted to gear box(p G)=P T x 0.95 (5) Where 0.95-efficiency of rotor shaft connecting gear box and shaft connecting DC generator Power obtained from DC generator (P gen)=p G x 0.9 (6) Where 0.9-efficiency of DC generator P gen= emf generated x total current produced (I g) (7) Emf generated[13]: ( PNx no. of conductors connected in series)/60 (8) Where -magnetic flux for alnico material (1.3 Tesla) taken from [14],N-rpm of shaft of generator, P-no. of poles in the DC generator(taken 1), no. of conductors connected in series-4 Rpm of the shaft of generator(n)is given by[6]:(v x TSR x 60)/(6.28 x2.5) (9) Where TSR-tip speed ratio(considered 7), 2.5-blade radius in m Current passing through inverter=(i h) (10) Current passing to house after converting into AC=0.85 x I h (11) Where 0.85-inverter efficiency Current passing to battery=i b (12) Current stored in battery=i b x 0.9 (13) (1) (2) 793 Kamaljyoti Talukdar

4 OBSERVATIONS Table 4.Observations for wind speed of 1.43 m/s in the month of October Parameters Velocity at 25m from ground Power by wind blades(p t) Power transmitted to rotor shaft(p T) Power transmitted to gear box(p G) Revolution of shaft of DC generator(n) Power obtained from DC generator (P gen) Emf generated by generator Current produced by generator(i g) Current passing through charge controller to inverter Observed values 5.07m/s W W W 135 rpm W 11.7 V A A Current passing through inverter(i h) Current passing to house after converting into AC by inverter Current passing to battery(i b) after passing through charge controller Current stored in battery Total current stored in battery in a day A A A A Ah 794 Kamaljyoti Talukdar Table 5.Observations for wind speed of 3.15 m/s in the month of May Parameters Velocity at 25m from ground Power by wind blades(p t) Power transmitted to rotor shaft(p T) Power transmitted to gear box(p G) Revolution of shaft of DC generator(n) Power obtained from DC generator (P gen) Emf generated by generator Current produced by generator(i g) Current passing through charge controller to inverter Current passing through inverter(i h) Current passing to house after converting into AC by inverter Current passing to battery(i b) after passing through charge controller Current stored in battery Total current stored in battery in a day Observed values m/s W W W 300 rpm W 26 V A A A A A A Ah

5 CONCLUSION Based on the discussion it is found that particular configuration shown in fig. 1 the house of particular appliances mentioned in table 1 can function well for different wind speed throughout the year in Kolkata city located in India. The calculations have been done for minimum(october) and maximum(may) wind speed because if it works well in this two months it will work well throughout the year for any wind speed. REFERENCES [1] Morren, J., and de Haan,S. W. H Short-Circuit Current of Wind Turbines With Doubly Fed Induction Generator. IEEE Transactions on Energy Conversion(March 2007), [2] 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(May 2012), [3] Timbus, A., Liserre, M., Teodorescu, R., Rodriguez, P., and Blaabjerg, F Evaluation of Current Controllers for Distributed Power Generation Systems. IEEE Transactions on Power Electronics(March 2009), [4] Li, S., Wunsch, D. C., O'Hair, E. A., and Giesselmann, M. G Using neural networks to estimate wind turbine power generation(sep 2001), [5] Erlich, I., Kretschmann, J., Fortmann, J., Mueller-Engelhardt S. and Wrede, H Modeling of Wind Turbines Based on Doubly-Fed Induction Generators for Power System Stability Studies(Aug. 2007), [6] (Accessed on ) [7] on ) [8] (Accessed on ). [9] on ) [10] (Accessed on ) [11] on ) [12] on ) [13] on ) [14] on ) 795 Kamaljyoti Talukdar