HYBRID SOLAR SYSTEM USING MPPT ALGORITHM FOR SMART DC HOUSE

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1 Volume 118 No , ISSN: (printed version); ISSN: (on-line version) url: doi: /ijpam.v118i10.81 ijpam.eu HYBRID SOLAR SYSTEM USING MPPT ALGORITHM FOR SMART DC HOUSE 1 S. Baskaran, 2 D. Lakshmi, 3 R. Zahira, 4 G. Ezhilarasi 1 Assistant Professor, S.A Engineering college,chenai, India. 2 Assistant Professor, Sree Sastha Institute of Engineering and Technology, Chennai, India. 3 Sr.Assistant Professor, Tagore Engineering College, Chenai, India. 4 Assistant Professor, Sri Sairam Institute of Technology, Chenai, India. Abstract: Solar energy is a non-polluting, non-depleting, site dependent source of energy. However it is of unpredictable nature. It is essential to develop a supervisory system which monitors and controls the energy production and also calculates the consumption. The solar power is very important in order to maintain balance between the production and the consumption. The Photovoltaic (PV) power systems convert sunlight directly into electrical energy. The total electricity requirement for the domestic utility can be sufficed. The excess power generated during the day can be utilized even during night by providing 24 hours electricity. This will allow comprising hybrid energy of grid and solar systems to operate the smart home loads. This consists of a PIC controller based design for cost effective operation of solar-grid tied system. The proposed method is efficient, cost efficient and reliable. A fly back converter is used to increase the solar power for operating home loads. An MPPT control is used to extract maximum power from the solar panel. Keywords: MPPT algorithm; PV Cell; PIC Controller; Hill climbing techniques; smart DC house. 1. Introduction The natural resources such as coal, oil, natural gases which are used for the production of electricity are getting depleted and affects both the environment and human health. Furthermore the uses of these resources leaves to the depletion of the resources available. Moreover scientists have also claimed that the conventional energy sources such as coal, natural gas are in the stage of getting extinct. So, the alternate energy source is solar energy. Solar PV modules are electronic devices with immovable parts that convert sunlight into direct-current electricity. Photovoltaic (PV) plays an essential role in the production of electricity as it does not produces any defects to both man and environment with increased production of current. It is noted that it has lower efficiency of conversion. It also makes use of the Maximum Power Point Tracker (MPPT). Solar panels generate power by using the photovoltaic effect: by phenomenon of irradiation. The electrons are transferred in different band levels in the atoms. The solar panel is used globally by using P-V characteristics. It means that for a different powers are obtained in the solar panel, at different operating point. Therefore, only for one specific operating point, the maximum power output is obtained from the solar panel. 2. Maximum Power Point Tracking Algorithms MPPT algorithms are necessary in PV applications because the MPP of a solar panel varies with the temperature and irradiation, so the use of MPPT algorithms is required in order to obtain the maximum power from a solar panel. These techniques differ in many aspects such as required sensors, complexity, sensors, range of effectiveness, cost, convergence speed, correct tracking when irradiation and/or temperature change, popularity or hardware needed for the implementation, among others. A complete review of 19 different MPPT algorithms can be found. Among these techniques, the P&O and the IncCond algorithms are the most common. These techniques have both advantages and drawbacks. Other techniques based on different principles are fuzzy logic control, neural network, fractional short circuit current or open circuit voltage, current sweep, etc. Most of these methods yield a local maximum and some, like the fractional short circuit current or open circuit voltage, give an approximated MPP, not the exact one. There is no problem as there a single maximum value for the V-P curve. Due to the multiple maxima in the array the shaded curves are present. In order to relieve this problem, different techniques have been implemented. 409

2 2.1 Hill Climbing Techniques Both P&O and IncCond algorithms are based on the principle of Hill Climbing that increases the movement of the operating point by which the power increases. The advantages of both methods are the low computation power they need and simplicity. The feature of the MPP is well known as it can keep track of the device even during the abnormal atmospheric conditions. 2.2 Perturb and Observe The P&O algorithm is also called as hill-climbing algorithm. Hill-climbing also has a perturbation on the duty cycle of the power converter and P&O between the power converter and the PV array. In the case of the Hillclimbing, duty of the perturbing and the power converter varies the voltage of the power converter and the DC array, so both names refer to the same technique. The perturbation are kept in the same direction, if the power increases and, the next perturbation should be in the opposite direction if the power decreases. Figure 1 shows flowchart of P&O algorithm. 2.3 Incremental Conductance The incremental conductance algorithm is based on the slope of power vs. voltage curve of the PV module is zero at the MPP, negative (positive) on the right of it and positive (negative) on the left. Figure 2 shows the algorithm for incremental conductance. Figure 1. Flow Chart of P&O 410

3 Figure 2. Flow Chart of Increment Conductance 3. Smart DC House Although, the use of DC in the home has a long history, AC is currently used almost in all domestic electricity supply with DC limited only to applications such as mobile homes and other leisure craft. In recent years interest in the use of DC in the home partly increased because DC voltages acts as a source for many modern home appliances and most renewable energy sources generate DC power. The normal use of AC therefore seems wasteful, as the energy is being converted with the use of converters, inverter and later it is converted back to D.C. The energy is saved by eliminating the multiple stage energy conversion, and CO emissions. The works on the usage of the D.C at home is concluded that it is not practical for cost and technical reasons. This research re-examines that the methodologies and assumptions used in previous work on DC. In comparison with the previous work whose goal was to determine if the DC voltage could substitute AC voltage in home appliances, the primary objective of this research was to assess whether. A novel bottom-up proposal is started with real DC loads which are found on the open markets. These DC loads are apportioned to different zones, cable spurs and power sockets and to determine the peak power of the DC voltage that directly correlates with real DC loads. Figure 3 shows block diagram of DC house. The DC House is designed to generate power in a home where there is no access to electricity. Unfortunate villages have improved their own style of living due to the development of DC house. DC power house also includes various types of generation, including human powered, hydropower, wind power, and photo-voltaic. There is a huge impact in the DC power transmission due to the new developments in the area of power electronics. The advantages of effective DC power transmission are: reduction of energy losses, integration of renewable energy resources such as PV, high power densities and simple coupling with storage systems. Authors have investigated that the feasibility of the adoption of direct current in medium and low voltage systems. It is shown that if the losses present in the DC-DC converters are considerably reduced, the losses in the system are decreased significantly when DC is used. DC to DC converters are the main usage in the field. 411

4 Figure 3. Block Diagram of DC House A. Modeling of the DC System DC system can be divided into three parts: the source, the DC grid, and the load. Modeling of these parts will be needed to perform load flow and short circuit. Performing load flow is an essential part of predicting efficiency of the system based on different main bus voltages. After modeling the source, DC grid, and the various loads the system will be interpreted into ETAP software where a power flow will be done. B. Modeling of the Loads One clear advantage of home automation is the unmatched potential for cost savings, and therefore energy savings. The thermostat is already smart and it uses the temperature to monitor the home's heating and the cooling system. In most cases, thermostats can also be programmed with the help of different target temperatures in order to keep energy usage minimum during the hours when you're likely to benefit from the cooling and heating. Table 1 shows the different types of loads. At the basic level, home automation extends the scheduled programmability to lighting, so that the energy usage is suited to daily schedule. With more flexible home automation systems, individual devices or even electrical outlets can also be automatically switched off for particular hour during the day when they're not needed. As with isolated devices like sprinkler systems and thermostats, the scheduling can be further broken down to distinguish between the weekends and seasons of the year. Some schedules are helpful, but many keep different hours from day to day. The programming of "macros" to the system reduces the cost of the energy and controlling it remotely whenever needed. Table 1. Modeling of loads 412

5 4. Simulation Analysis Figure 4. Proposed Simulation Diagram Figure 4 shows the proposed system simulated block diagram. Figure 5 shows the solar voltage waveform, Figure 6 gives the Grid voltage after rectification, Figure 7 shows voltage adder output, Figure 8 represents PWM signal waveform, Figure 9 gives Fly back voltage and Figure 10 shows load voltage. Figure 5. Solar Voltage Waveform 413

6 Figure 6. Grid voltage after rectification Figure 7. voltage adder output Figure 8. PWM signal waveform 414

7 Figure 9. Fly back voltage Figure 10. Load voltage 5. Hardware Prototype This prototype explains that solar output dc voltage is boost up with fly back converter and add up with ac grid by rectification of AC voltage where pic is use to control mosfet which is use to turn on and turn off voltage by pulse width modulation technique. The added DC voltage is then given to dc loads. Figure 11 shows hardware prototype of the proposed system. Figure 11. Hardware Prototype 415

8 6. Conclusion In this project, a fly back converter based MPPT technique has been proposed to track the maximum power point of a photovoltaic system. The solar and grid voltages are added to operate home loads as a MVDC system. The proposed algorithm has been designed and developed in Matlab / Simulink and it has been found that the proposed algorithm can track the MPP with much less iteration than the traditional algorithm. The proposed concept of hybrid energy system has been experimentally verified by a hardware prototype model. References [1] Azadeh Safari, Saad Mekhilef, Simulation And Hardware Implementation Of Incremental Conductance MPPT With Direct Control Method Using Cuk Converter IEEE Pow. Elec. and Motion Cont. Conf. (EPE/PEMC), [2] Busco, P. Marino, M. Porzio, R. Schiavo, And F. Vasca, Digital Control And Simulation For Power Electronic Apparatus In Dual Voltage Railway Locomotive, in IEEE Applied Power Electronics Conference & Exposition (APEC), 2014, pp [3] X. Chen, H. Sun, J. Wen, W. J. Lee,X.Yuan,N. Li, And L. Yao, Integrating Wind Farm To The Grid Using Hybrid Multiterminal HVDC Technology, in IEEE Applied Power Electronics Conference & Exposition (APEC), 2014, pp [4] Z. Liang, R. Guo, J. Li, And A. Q. Huang, A High-Efficiency PV Module Integrated DC/DC Converter For PV Energy Harvest In FREEDM Systems, IEEE Pow. Elec. and Motion Cont. Conf. (EPE/PEMC), [5] P. Leander And S. Ostlund, A Concept For An HVDC Traction System, in IEEE Applied Power Electronics Conference & Exposition (APEC), 2014, pp

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