Maximum Energy Extraction in Wind Solar Hybrid Energy Conversion System

Transcription

1 European Journal of Scientific Research ISSN X Vol.63 No.1 (2011), pp EuroJournals Publishing, Inc Maximum Energy Extraction in Wind Solar Hybrid Energy onversion System P. Aravindan Associate Professor / Dept of EEE K.S.Rangasamy ollege of Technology, Tiruchengode. Tamil Nadu. India paravindan@rediffmail.com Tel: S. Thangavel Professor and Head / Dept of EEE K.S.Rangasamy ollege of Technology, Tiruchengode. Tamil Nadu. India M. Y. Sanavullah Dean / Electrical Sciences V.M.K.V Engineering ollege, Salem. Tamil Nadu. India Abstract In this research paper an energy system composed of three energy conversion devices namely, photovoltaic panels, a wind turbine, and a battery is proposed. This controller directs power to a fixed voltage D bus. The fixed voltage bus supplies the load, while the excess power is directed to the batteries. Simulation and control of a hybrid PVwind generator system connected to the load are presented in this paper. Every major component of the system is modeled, and then different control strategies are applied to the system. To improve the performance of the system under different environmental conditions. Maximum Power Point Tracking (MPPT) of the photovoltaic system and blade angle pitch control of wind turbines are included. Keywords: MPPT, Hybrid Wind Solar, Maximum Energy Extraction, FL. I. Introduction In the growing industrialization and domestics, power demand is increasing enormously. To maintain the green environment we have to generate power from the various renewable energy sources in environment friendly manner. In present the bulk ac power transmission are not economic and also complicate to control the power flow. To overcome this problems wind turbine and photovoltaic generators are used. The proposed hybrid model is most suitable for all weather conditions. And also, it is very safe working atmosphere with the hybrid model. Wind and solar energy is unsteady and unpredictable, and harnessed in relatively small quantities spread over a large area. If it is not properly controlled, the power output of a wind farm and PV array could too small percentage only. In this paper permanent magnet synchronous generator is used with variable speed control employed [1]. The flux in the generator is controlled by field controlled method, and speed Vs torque characteristics controlled by PI controller. Similarly, another one power produced by PV panel. In this

2 Maximum Energy Extraction in Wind Solar Hybrid Energy onversion System 91 paper power management is done by maximum point power tracking algorithm method (MPPT) individually. Because, the power produced in both method are not equal. Figure 1: Block diagram of Proposed Hybrid model. In this proposed model two groups are presented. First group is permanent magnet synchronous wind generator and it is connected to A/D converter and common D-link. On the other hand, second one is Photovoltaic (PV) array and it is connected to D/D converter and common D link. The maximum point power tracking of generator and PV array is done by MPPT algorithms. The feedback is taken from both power generator and also from common D-link as an input to the power management algorithm block. This is very easy and convenient method for controlling the generator and D link compared with existing method II. Modeling of Wind Turbine Generally, wind turbines are two basic configurations according to the shaft arrangement types are horizontal axis (HAWM) and vertical axis wind machines (VAWM). Presently, most wind machines being used are the horizontal-axis type due to heavier and less expensive rotor compare with VAWM. And also VAWMs are not economically competitive with HAWMs. In this paper horizontal axis permanent magnet synchronous wind generator is implemented [2]. The basic equation for electric power generated by a wind turbine is 1 3 P r = 2 ρ sv (1.1) Where P = electric power output from a specific wind generator V= wind velocity (meters/second) p density of air at turbine blades S =Surface swept of wind turbine The power contained in the wind is not fully extracted by a wind turbine. This is due to losses incurred in the energy conversion process, also because some of the air is pushed aside by the rotor and it is passing the blade without generating power. The relationship with power recovered and available power is known as power reactivity coefficient p. Here output power is P 1 2 Ω 3 5 t t = p pπr 3 (1.2) Ω t λ λ = R (1.3) V

3 92 P. Aravindan, S. Thangavel and M. Y. Sanavullah Where =ratio between linear speed and the wind speed R=radius of the speed tωlinear speed of the blade extremity. A typical curve of p versus is shown in Fig 2. The maximum value of power is occurred at a specific speed ratio. Hence, the natural wind is always not constant, and it is necessary to adapt the shaft speed to find the maximum power gain point. Eventually, the maximum value of power point in permanent magnet synchronous generator can be transferred from the air stream to the wind turbine to produce the maximum electrical power by using vector control method. Figure 2: urve for p ersus Fig 2 represent different speed of natural air stream driven by the permanent magnet synchronous wind generator produced maximum power condition characteristics. The mechanical equation for permanent magnet synchronous generator is given by dω mec g mec = J + dt t vis Ω mec = M. Ω (1.5) M Where, otal friction torque (1.4) t g = (1.6) vis Figure 3: Power Output versus Wind Speed

4 Maximum Energy Extraction in Wind Solar Hybrid Energy onversion System 93 III. Vector ontrol and MPPT Figure 4: MPPT algorithm Algorithm Operation Fig.3. shows that the goal of MPPT and vector control method is to find maximum power point and operate at optimal is achieved. In the Fig.4 proposed maximum power point algorithm operated at without measurement values of wind speed. The permanent magnet synchronous machine is supplied the three phase PWM inverter to control required flux and torque with speed as a feedback taken from machine. IV. Modeling of PV Panel In this module the solar cells is a fundamental power conversion unit of a photovoltaic system. Fig 5 represents the equivalent circuit of a PV module system. Figure 5: Equivalent ircuit of PV Module

5 94 P. Aravindan, S. Thangavel and M. Y. Sanavullah Figure 6: Power-Voltage urve of PV Module The output power of the PV panel and the voltage characteristics is obtained is shown in Fig 6. The maximum power tracking point is achieved from this curve and its maximum depends on the maximum polarization of the solar cell module [3]. I = I I I (3.1) p L D Rsh I I I V R I V R I s. s. p = L 0{exp[ ] 1} (3.2) VT R sh Where, I =hoto current L I =iode current D I Rsh =hunt current Normally, voltage output is based on solar irradiation and temperature of the cells. The fuzzy logic controller (FL) is added to obtain the voltage for which the peak value of power achieved from PV cells. P and V are used as seven input variables of the fuzzy controllers. The output variable is an increment value which increases or decreases the voltage reference of the PV array. Then the PWM duty cycle of the boost converter connected to the D-link. V. Energy Storage and ontrolling An extracted energy from the hybrid system is needed to store in the battery for the continuous supply to the D load even though the energy sources are not available in all the environmental cases. The energy is stored with the help of buck-boost converter. It acts as a buck converter during storing and boost converter during the supplying the load through D-link. In that proportional integral controller is used for controlling energy storing in the batteries. The ripple free current and constant voltage V B is achieved by the proposed control scheme as shown in the fig.7. Figure 7: PI Energy Storage ontrol

6 Maximum Energy Extraction in Wind Solar Hybrid Energy onversion System 95 VI. Simulation Output MATLAB simulation study is used for the proposed wind-pv module system. The various control strategies and performances were studied by simulink software [5]. The MPPT and vector control maximum power point are tracked at constant wind speed shown in Fig 8. Figure 8: MPPT at onstant Wind with Wind Power If the wind speed is changed, the tracking of maximum point stabilization of the shaft speed and windmill power around the maximum power operating point is achieved by the proposed algorithm. The Fig.9 shows the Vector control of the permanent magnet synchronous generator and MPPT methods direct the windmill to operate suitably at optimal power. Figure 9: Maximum Power Point at Growing Wind Speed Figure 10a: Simulation Output of Windmill Permanent Magnet Synchronous Generator with Variable wind, (Generator speed)

7 96 P. Aravindan, S. Thangavel and M. Y. Sanavullah Figure 10b: Simulation Output of Windmill Permanent Magnet Synchronous Generator with Variable Wind (Power output) In that show that simulated result of permanent magnet synchronous windmill for the variable wind output from the Fig10a & 10b.when the speed of the wind changes the maximum power output of the permanent magnet synchronous generator model get also grow from the comparisons with Fig 10a&b and Fig 11a&b. Figure 11a: Simulation Output of Windmill Permanent Magnet Synchronous Generator with onstant Wind (Power output) Figure 11b: Simulation Output of Windmill Permanent Magnet Synchronous Generator with onstant Wind (Torque)

8 Maximum Energy Extraction in Wind Solar Hybrid Energy onversion System 97 Similarly PV module is simulated and integrated with the windmill. In order to evaluate the performance output of PV cells in the MPPT - FL strategy is used. Fig.11 presents the power point tracking around its maximum value for a constant irradiance. The FL response allows the maximum power to be achieved quickly when compared to other methods. Fig.12 shows how the energy storage is managed in batteries and control the performance output of the converter at variable load. Figure 12: Power Output of PV Panels from MPPT-FL controller. Figure 13: D-D onverter D-Link urrent VII. onclusion and Future Scope The simple and most efficient integrated windmill with permanent magnet synchronous generator and PV solar cell system are proposed with MPPT algorithm. The advantages of MPPT algorithm are robustness and the easy to implement when compared to the several maximum power point tracking methods available [4]-[7]. It also facilitates to evaluate the wind mill features easily and accurately. Also, this hybrid generation system takes a different merit that the wind-pv power naturally complement one another to certain amount, there by facilitating continuous output power for full day to the load. In future the fuel cell also taken in to the account to achieve not only the continuous supply but also better battery life.

9 98 P. Aravindan, S. Thangavel and M. Y. Sanavullah References [1] hunhua Liu, K. T. hau, and Xiaodong Zhang, An Efficient Wind Photo voltaic Hybrid Generation System Using Doubly Excited Permanent-Magnet Brushless Machine, IEEE Trans. Ind. Electronics, vol. 57, no. 3, Mar 2010 [2] Seul-Ki Kim, Jin-Hong Jeon, hang-hee ho, Jong-Bo Ahn, and Sae-Hyuk Kwon, Dynamic Modeling and ontrol of a Grid-onnected Hybrid Generation System With Versatile Power Transfer, IEEE Trans. Ind. Electronics, Vol. 55, No. 4, April 2008 pg no:1677 [3] Weidong Xiao,, Nathan Ozog, and William G. Dunford Topology Study of Photovoltaic Interface for Maximum Power Point Tracking, IEEE Trans. Ind. Electronics, vol. 54, no. 3, June [4] Trishan Esram, and Patrick L. hapman, omparison of Photovoltaic Array Maximum Power Point Tracking Techniques IEEE Trans. Energy onversion, vol. 22, no. 2, June 2007 [5] Eftichios Koutroulis and Kostas Kalaitzakis Design of a Maximum Power Tracking System for Wind-Energy-onversion Applications, IEEE Trans. Ind. Electronics, Vol. 53, NO. 2, April 2006 pg no: [6] Quincy Wang, and Liuchen hang, An Intelligent Maximum Power Extraction Algorithm for Inverter-Based Variable Speed Wind Turbine Systems, IEEE Transactions On Power Electronics, Vol. 19, No. 5, September 2004 pg no: [7] Fernando Valenciaga and Paul F. Puleston, Supervisor ontrol for a Stand-Alone Hybrid Generation System Using Wind and Photovoltaic Energy, IEEE Trans Energy onversion, Vol. 20, NO. 2, June 2005 pg no: