The commonly used Uninterrupted Power Supply systems take its power directly from the supply mains and consumes much higher energy for its functioning. Considering the energy availability crisis and higher living cost, it is necessary to find an alternative power source for such a system. Here, we propose a system to design a UPS which will utilize the everlasting solar and wind power, thereby checking the energy crisis to a certain limit and is termed as “Hybrid Solar Wind Charger”.
Since hybrid systems include both solar and wind power, they allow the power user to benefit from the advantages provided of both forms of energy. Obviously, solar panels don’t provide power during the night, but that’s when the wind usually picks up and conversely, on the longest, hottest days of days of summer, the wind often doesn't blow, but the sun is at its strongest great for solar power. The wind is more likely to blow during the cold, short days of winter when the sun is at its weakest. A purely solar power solution for general lighting load is very expensive as far as initial investment is concerned. Also, due to frequent power failure, a regular battery backup UPS/INVERTER barely gets time to charge the battery from mains. The hybrid version combines solar energy, wind energy and mains utility to give an excellent solution by providing the best of both worlds. While proposing this project of designing a hybrid charger, the following data must be taken into account.
Although fossil fuels have led us to economic prosperity, the extensive use has caused a substantial reduction of fossil fuels. Therefore, the solar energy, as one of the green energy resources, has become an important alternative for the future. It can be considered to use the parallel loaded resonant converter with the feature of the soft switching technique in the circuits of the solar storage battery charger. To avoid the damage of the battery charger due to the variation of the output current of the solar PV panels, a closed-loop boost converter between the solar PV panel and the battery charger was designed to stabilize the output current of the solar PV panel. By designing the characteristic impedance of the resonant tank, the charging current of the storage battery can be calculated and then the charging time for the storage battery can further be estimated.
By properly designing the circuit parameters, the parallel loaded resonant converter can be operated in the continuous current conduction mode and the switch can be switched for conduction at zero voltage. Such experimental results verified the correctness of the theoretic estimation for the proposed battery charger circuit. The average charging efficiency of the battery charger can be up to 88.7%. It is estimated that about 80% of all photovoltaic (PV) modules are used in stand-alone applications. Continuous power is obtained from PV systems by using a storage buffer, typically in the form of a lead acid battery. Batteries used in PV applications have different performance characteristics compared with batteries used in more traditional applications. In PV applications, lead acid batteries do not reach the cycle of lead acid batteries used in other applications such as uninterrupted power supplies or electric vehicles. The shortened battery life contributes significantly to the costs of a PV system. In some PV systems the battery accounts for more than 40% of the life cycle costs. An increase in the lifetime of the battery will result in improved reliability of the system and a significant reduction in operating costs. The life of a lead acid battery can be extended by avoiding critical operating conditions such as overcharge and deep discharge. So battery management system is necessary for such applications. The test results have shown that with proper setup, amp-hour counting charge control is more effective than conventional voltage regulated sub array shedding in returning the lead acid battery to a high state of charge.
We need an effective, robust and reliable solar battery charging algorithm for the widely used batteries; NiCd, NiMH, Lead-Acid and Lithium-Ion. The algorithm has the ability to charge the battery in the outdoor conditions, when the power is variable, and terminate charging when the battery is fully charged. The algorithm has two modes of operation; current mode and voltage mode. It can deal with the unexpected outdoor conditions, which may cause drops in the current, without falsely detecting the battery state of charge. A programmable power supply was programmed and the four battery types were charged to test the algorithm. A microprocessor controls the charging profile of the battery.
The estimation technique for solar battery charger based on lithium battery can also be considered while doing this project. The lithium battery is used for storing solar generated power. The solar battery charger requires solar cell voltage and current, battery voltage and current for controlling solar cell and battery status. But due to the unstable hazardous behavior of the lithium battery, it is required to have double protection function in the solar battery charger. A low-cost battery management relay controller, enabling near-optimum utilization of a solar photovoltaic array, connected to an off-the-shelf uninterruptible power supply, for daytime grid-connected operation can be studied for a higher efficient operation.
We have to design an intelligent battery charger controller just like in the case where solar energy can be used as an additional energy source for hybrid automobiles using gasoline and electricity for which the design idea is implemented and tested. The experimental project successfully demonstrates the feasibility of boosting a solar panel generated low voltage (24 V) energy source to a desired high voltage (150 V) for charging a battery pack. The result demonstrates that solar energy can be used as an additional clean energy source for hybrid automobiles.
The maximum power point tracking (MPPT) control for stand-alone solar power generation systems can be considered to do by means of fuzzy-model-based approach. In detail, we consider a dc/dc buck converter to regulate the output power of the photovoltaic panel array. First, the system is represented by the fuzzy model. Next, in order to reduce the number of measured signals, a fuzzy observer is developed for state feedback. Then, a fuzzy direct MPPT controller is proposed to achieve asymptotic MPPT control, in which the observer and controller gains are obtained by separately solving two sets of linear matrix inequalities. Different from the traditional MPPT approaches, the proposed fuzzy controller directly drives the system to the maximum power point without searching the maximum power point and measuring isolation. Furthermore, when considering disturbance and uncertainty, robust MPPT is guaranteed by advanced gain design. Therefore, the proposed method provides an easier implementation form under strict stability analysis. Finally, the control performance is shown from the numerical simulation and experimental results.
The study of solar radiation simulation by taking the daily distributions of solar radiation are presented for various clearness indexes, kt. Additionally, taking into account the studies about solar radiation, a photovoltaic array system and a DC/DC buck - boost converter are studied. Simulation of the whole system is presented focusing on DC/DC converter control strategy so that the system operates in maximum power point (MPP) and converter output voltage remains constant. Incremental conductance algorithm is used for maximum power point tracker (MPPT) implementation. A simplest method for controlling duty cycle D and photovoltaic array voltage by using a new variable (d = D/1-D) is proposed and the simulation results are shown and analyzed. For the implementation of this system, the dsPIC30F2010 Microchip, microcontroller can be programmed to provide pulses to the semiconductor element of the DC-DC converter in order to track the Maximum Power Point (MPP) of the photovoltaic array.
The term "temperature coefficient" has been applied to several different photovoltaic performance parameters, including voltage, current and power. The procedures for measuring the coefficient(s) for modules and arrays are not yet standardized and systematic influences are common in the test methods used to measure them. There are also misconceptions regarding their application. Yet, temperature coefficients, however obtained, play an important role in PV power system design and sizing, where often the worst case operating condition dictates the array size. Therefore effective methods is to be found for determining temperature coefficients for cells, modules and arrays; identifies sources of systematic errors in measurements; gives typical measured values for modules and provides guidance for their application in system engineering.
The studies have shown the advantages of the "solar-Diesel" hybrid systems compared to other models of fuel savers for telecommunication stations distant from commercial power lines. With a much smaller initial investment, practically the same reliability can be obtained as with 100 percent solar solutions. The idea is to put to use all the available energy of the sun with fewer solar panels, which may be called "Total Solar Energy System". Of course, it is necessary to maintain within the limits of a reliable operation the minimum state of charge of the battery. In practice this can be achieved by the use of a battery charger (Diesel-group or other) and a control system. The result can be used to make the project of hybrid solar systems. The formulas permit us to calculate, for a given site and system, all operational characteristics such as: - state of charge of the battery at the end of each month - monthly number of operation and operating time of the charging group - economy in fuel compared to 100% Diesel system Practical data and results in Brazil have proved the theory.
Hence, by means of this project we aim for the better utilization of solar energy for delivering steady supply to the loads and meet the energy crisis to a great extent. This will help in the reduction of the electricity bill thereby resulting in the lesser cost of electricity generation per unit.