IEEE T&D Asia 2009 Renewable Energy Distributed Power System With Wind Power and Biogas Generator Zhang Yanning1, Kang Longyun1, Cao Binggang2, Huang Chung-Neng3, Wu Guohong4 (1. School of Electric Power, South China University of Technology, Guangdong key laboratory of Clean energy technology, 510640 Guangzhou China;2. Institute of Mechanical Engineering, Xi’an Jiao Tong University, Xi’an 710049,china; 3.National University of Tainan, Tainan City, Tainan 700, Taiwan; 4.Electrical Engineering and Information Technology at Tohoku Gakuin University,985-8537, Japan) large local communities. When DPS generate more power than Abstract: The energy shortage and environment pollution is receivers and local energy storage systems require, they is onattracting more and more attention with the social development. grid-connected to provide surplus power to the grid. Obviously,Hence it is important to develop new energy and renewable the major aim of DPS is to supply remote, off-gridenergy that are bio-energy, wind energy, solar energy, small communities where the costs of connection to thewaterpower, tide energy, terrestrial heat energy, and hydrogen long-distance transmission or distribution grid are too high.energy and so on. The research of distributed power system with DPS use few technologies connected with power generationthe solar and wind power is the leading domain. It is known to all such as different power generation devices, different energythat the wind generation system is enslaved to the weather, the storage technologies and advanced microprocessor controlmicro net composed by them don’t supply the steady electricity. supervision systems.The biogas is produced from anaerobic biodegradation of organic The renewable energy distributed power systems arematerial in the absence of oxygen and the presence of anaerobic cooperated by renewable energy; they contain two or moremicroorganisms. The plant, animal dejecta, and rubbish are the power generation sources in order to balance each other’ssource, so the biogas can be gotten very easily. The biogas strengths and weaknesses . There are many types DPS suchgeneration can be supplying the steady electricity and the output as: DPS with wind power and solar; DPS with wind power andpower can be control. Thus the authors present the wind-biogas fuel cell; DPS with wind power, solar, fuel cell [4-9]. Theserenewable energy distributed power system, and the biogas sources are environmentally friendly and use primary energygenerator is employed to balance the output power of the system. carriers such as solar, wind and biogas, biomass etc. TheThis system can keep the constant output power under control. sources mentioned above can be divided into two groups: controlled sources and uncontrolled sources. Controlled Key Words: Renewable Energy, Distributed Power System, sources mean that the output power can be easily controlled toWind Power, Biogas Generator the goal power; for example biogas. It is obvious that output power from uncontrolled sources is unpredictable and 1. INTRODUCTION independent of human action. Solar and wind power plants are There are many deﬁnitions of Distributed Power System. environmentally uncontrolled sources.Our deﬁnition of DPS is as follows [1,2]: small set of For the user, electricity should be produced exactly at theco-operating units, generating electricity or electricity and heat, time it is needed. Wind power does not meet this requirement.with diversiﬁed primary energy carriers (renewable and So, special kind of power plants should be built to avoidnon-renewable), while the co-ordination of their operation shortages of wind power. The biogas is introduced to balancetakes place by utilisation of advanced power electronics the electricity of wind power.systems. Mostly DPS are connected to the power grid; furthermore 2 THE WIND-BIOGAS RENEWABLE ENERGY SYSTEMthey can also work independently feeding separated receivers, The wind power is influenced by the weather; the outputfrom one or several homes/farms, small industrial plants to power is determined by the wind speed. It is known to all that
the wind speeds are changed with the time and space. The DPS Thuswith the wind power system is not satisfied to the user need. PG 0 (2)Biogas is produced from anaerobic biodegradation of organicmaterial in the absence of oxygen and the presence of Where, P , PB , PE , PL , P are the powers of wind, biogas, W Ganaerobic microorganisms. The biogas generation is developedwith the biogas usage. The biogas produced by the waste of battery, load and grid, It means that the DPS provide theindustry, agriculture and town is fired to drive the engine to electricity to the grid. When the relation is shown as:generate electricity. Pw PB PE PL (3) The biogas generation is under control and can provideelectricity to balance the output power of wind generation, the The battery gets the electricity from the DC bus or gives theDPS with wind and biogas is shown as fig1. electricity according to the user load. When the relation is shown as Pw PB PE PL (4) Thus PG 0 (5) It means that the DPS can’t satisfy the need of the user and get the right electricity from the grid. The DPS under control is shown above. 2.2 Capacity of Hybrid System Fi The hybrid system of wind generator and biogas generator g 1 wind-biogas DPS is a good choice for the remote user. It is known to all that the output power of wind generator is varied with the wind speeds2.1 Power Flow of System change. Thus the output power is varied from the power of The output current of the wind generation is transformed to starting wind speed to the rating power. The output powerthe DC current by AC/DC and is connected to the DC bus, the range is big, which is not good for the user. To keep thebiogas generation is connected to the DC bus with AC/DC. constant power out the capacity of biogas must be right for theThese generators controllers are connected to the system hybrid system.controller. The current of output power is described as fig2. The start working wind speed is v1 and the rating power is PE at the rating wind speed vE. The relation between the wind speed and the output power is shown as P Kv3 (6) Where, K is a parameter which is a constant at a speed. It is concluded that the output power is third order direct ratio to the wind speed. The minimal power of wind generator can be easily gotten by equation Fig2 current of output power v1 P1 PE (7) vE There are three cases according to the relations between thesepowers. When the relation is shown as: The output power of wind generator on whole day is presented as Pw PB PE PL (1)
main idea behind this method is to control the reaction torque 0 P PE (8) of the generator via changing the winding voltage and the The biogas generator is usually composed by the motor and output current.gas engine. The efficiency of engine is high from a powerpoint to rating output power. Assuming that the output powerof biogas generator is Pb, it is shown as Ps Pb PbE (9)Where, Ps is the start power with the high efficiency, PbE is therating power of biogas generator. Assuming that the load is Pl, it is shown as Fig3 VSCF wind turbine 0 Pl PlE (10)The stable electricity supply is important to the user; hence the For the fixed pitch wind turbine, the torque produced by therelation between the capacity of wind generator, biogas wind energy could be described as follows:generator and load is shown as Pf 1 3 Tf Cp R2 Pl Pb P (11) g 2 g (14)Comparing these relations the capacity of biogas generator is 1 Cp R3 2presented as 2 Where p is the density of the air, R is the radius of the blade; V Ps PlE (12) is the wind speed; Cp is the coefficient. The dynamic performance of wind turbine could be 3 CONTROLLER DESIGN described as follows: The wind-biogas system is a complex system which the d gwhole model is difficult to exactly get, thus the control design Jg Tf Tg B g (15)is the key to the good electricity. The controller of the system dtis separated to two parts, one of which is the controllers of Where Tg is described as follows:wind generator and biogas generator, and the other is the chiefcontroller. The controller of wind generator is designed to get Tg p ig k g igq (16)the max energy from the wind, the controller of biogasgenerator is designed to get the need power by adjusting the Where k is the ratio of boost-bucker converter, and igq is themass of the input biogas. current of DC bus.3.1 Wind Generator 3.2 Biogas Generator The wind speed input model of wind generation is shown The controller is also designed to track the maximum outputas: power and keep the constant output voltage. The biogas 1 3 generation is shown as fig4. p v1 SC p 2 (13)In the (13) is the air density, v1 is the up wind speed, s is thearea that the wind past through the wind turbine vane, Cp isthe coefficient of wind energy use. The rotor speed of the wind turbine is controlled through theadjustment of ration of Boost-bucker, as shown as fig3. The Fig 4 biogas generation
The instantaneous power is shown as K1 c (25) pVni Pi 17 120Where, i is number of gas vat. The output torque is described 4 SIMULATIONSas: The hybrid system of wind generator and the biogas generator is made up and the research on how to track the max 9550 Pi m Ttq point of wind generator and the research on how to make the n 30 output power follow the order quickly have being already done. n 18 But the whole system controller is on designing. The d simulations are done first to validate the control ways. The dt capacity of hybrid system is confirmed by 2.2. The ratingWhere, m is the availability efficiency. power of wind generator is 7Kw; the rating power of biogas The control model of biogas generation is described as generator is 20Kw. d The reference wind speed is 15m/s, the radius of wind J Ttq Te Tf (19) dt turbine is 10m, and the moment of inertia is 1270. The controlFrom the (19) it is also shown as result with the wind speed of 15m/s is shown as fig5. d2 d J Ptq Pe B (20) dt 2 dt3.3 ADRC The ADRC of wind turbine is designed as follows.(1)TD of this system is presented as: x1 rfal ( x1 v, a, ) (21)Where, v is the input signal, x1 is the tracking signal.(2) The ESO of first order system is presented as z1 z2 1 fal ( z1 , a, ) u (t ) (22) Fig 5 rotor speed controlled by ADRC z2 2 fal ( z1 , a, )Where, z1 is tracking the real rotor speed , z2 is detecting The gas engine simulation at the rotor speed 1500 r/min is g shown as fig 6.the wind input torque.(3)The NLSEF of first order system is presented as e1 v z1 u0 K1 fal (a, , e1 ) (23) u u0 z3The linear model is also first considered and is proposed as e1 v z1 u0 K1e1 (24) u u0 z3 Normally the K1 is also calculated by the transfer function Fig6 result of simulationand follow the rules of TD gains r, the gains K1 is proposed as
The dc load is 15Kw, the output power of wind generator, The dc voltage is little vibrated at 400V. The simulationsthe output power of biogas and the dc voltage is shown as prove that the hybrid system of wind generator and biogasfig7 fig8 and fig9. generator provides the stable electricity to the user. 5 CONCLUSIONS The renewable energy is attracting more and more attention for its clean. The biogas is produced by waste and dead plant. The wind generator is widely applied in the world and many other generators are introduced to combine. The biogas generator is only restricted by the marsh gas pond. It is controllable and the capacity can be planed. The hybrid system of wind generator and biogas generator keep the stable output electricity by simulations. Reference  IURC Staff ,Distributed Generation White Paper[A],2002,1,1 13. Fig7 output power of wind generator  M.A. Uyterlined, E.J.W. van Sambeek, E.D.Cross, Decentralised Generation:Development Of Eu Policy[A],Energy Research Center Of The Netherlands,2002,10,9 69.  B. Ozerdem, H.M. Turkeli,Wind energy potential estimation and micrositting onIzmir Institute of Technology Campus[J], Turkey,Renewable Energy 30 (2005) 1623–1633.  M.T. Iqbal,Simulation of a small wind fuel cell hybridenergy system[J],Renewable Energy 28 (2003) 511–522.  J.G..Mcgowan,J.F.Manwell, Hybrid Wind/PV/Diesel system Experience[J]. Renewable energy. 1999,Voll6(3): 928-933.  Paul B.Tarman. Fuel cells for distributed power generation[J]. Journal of Power Sources. 1996,Vol61(1): 87-89.  .M.T.Iqbal. Modeling and control of a wind fuel cell hybrid energy system[J]. Renewable Energy. 2003,Vol28(2): 223-237.  Leonidas Ntziachristos, Chariton Kouridis, Zissis Samaras, Konstantinos Pattas,A wind-power fuel-cell hybrid system studyon the non-interconnected Aegean islands grid[J],Renewable Energy 30 (2005): 1471–1487.  M.J. Khan, M.T. Iqbal,Dynamic modeling and simulation of a smallwind–fuel cell hybrid energy system[J],Renewable Energy 30 Fig8 output power of biogas generator (2005) 421–439. BIOGRAPHIES Zhang Yan-ning was born in Ningxia Province of China, on January, 1978. He received the Bachelor from Xi’an University of Technology, Xi’an, China, in 2000, and the Master in 2003. He is a graduate student of Xi’an JiaoTong University; his main research is renewable energy usage and control theory. The telephone is (o) +086+029-82665331; the mobile phone is (m)+086+13488358928; the Email is email@example.com; the Address is No.28 Xian Ning West Road, Shanxi, Xi’an, China and Post code is 710049. Fig9 dc voltage
Kang Long-yun was born in Jiling province of china experts who programs the development of universities belonging to ministry on 1961. He is an advisor of doctor students, is a of education, and a member of experts commission of Science Chinese since professor of School of Electric Power, South China Nov. 2001 University of Technology. He received the Bachelor from Yanbian University CN in 1982, Master and Chung-Neng Huang Chung-Neng Huang (M 04) received the B.S.E.E. from Doctor from Engineering Department of Kyoto National Taiwan University of Science and Technology, Taipei, Taiwan, in University, in 1996 and 1999. He is addressing on the 1992, and the M.S.E.E. and PH.D. degrees from Tohoku University, Sendai,renewable energy, such as distributed power system, photovoltaic automobile. Japan, in 1997 and 2000, respectively. He is an associate professor at National University of Tainan, Tainan City, Taiwan. His main research interests are Cao Bing-gang was born in Gansu Province of mechatronic system, hybrid-power control, and vehicular electronics. China on 1953, He is an advisor of doctor students , dean of Mechanical Engineering School of Xian WU GUO-HONG Guohong Wu was born in Tianjin, China,on 26 September Jiaotong University, a director of Research 1969. He received his B.S. and M.S. degree in electrical engineering from Development Center of Electric Vehicle, is dean of Tianjin University,China in 1989 and 1994, respectively. In 1998, he reeived aCenter of Vehicle Engineering in Xian Jiaotong University as well as head of joint-supervised Ph.D.degree from the University of Tokyo, Japan and TianjinResearch Institute of System Monitoring & Diagnostics. He has been a vice University. He was with the University of Tokyo from 1995 to 2001, as a Ph.Ddirector of Electric Vehicle in Shannxi Province and a member of Editorial student, a research associate and a postdoctoral fellowship, respectively. FromBoard of Journal of Xian Jiaotong University and Asian 2001 to 2005, he worked with Tohoku University, Japan. He is currently anInformation-Science-Life which is an international journal. Furthermore, he is associate professor of Electrical Engineering and Information Technology atone of experts who recognise name-brand products in Xian City, one of Tohoku Gakuin University, Japan. Dr. Wu is a member of IEEE and IEEJ.