To maximize the use of available solarpower drawn from the solar panel and to widen the applications of solar energy, several studies have investigated the design and applications of buck-boost converters [3–7]. Few studies have developed buck-boost converters for portable applications [4,5], whereas the study in  proposed a buck-boost-cascaded converter for high-power applications such as fuel-cell electric vehicles. Furthermore, an extensive analysis and design of Li-ion battery charging with the use of a four-switch type synchronous buck-boostpowerconverter was presented in . In the current research, we conducted a comparative study for MPPT evaluation by using differentbuck-boostconvertertopologies through circuitsimulation, including Zeta, a single-ended primary-inductor converter (SEPIC), and four-switch type synchronous buck-boost converters.
Energy Crisis and climate change threats leads the researchers to look for alternate sources of energy [1-3]. The world is virtually on the hunt of promising renewable and sustainable sources of energy. In recent years, renewable energy sources like solar, wind, tidal, have attracted the researchers, as it is limitless, non-pollutant and available free of cost. Solar energy is considered as the most reliable source among RES. Due to technological advancement in power electronics and reduction in the manufacturing cost of PV cell, solar energy is becoming more promising source of energy [4-8]. Solar PV exhibits nonlinear characteristics and its efficiency is also low. It becomes essential to extract maximumpower from solar PV under all ambient conditions. MPPT (MaximumPowerPointTracking) algorithm is used to extract maximumpower from solar PV [9-10]. The MPPT is implemented in the control circuit of Power electronics converters. A converter without MPPT system only regulates the output voltage of PV module, but it does not ensure that PV system is operating at the maximumpowerpoint MPP . The operation of MPPT depends on the type of converter used [12-14]. In this paper a boost dc-dc converter is used and the performance of MPPT is evaluated.
Maximumpowerpointtracking, frequently referred to as MPPT, Tracking the maximumpowerpoint (MPP) of a photovoltaic array is an essential stage of a PV system The efficiency solar panel is improved by MaximumPowerPointTracking (MPPT) when they set to operate at point of maximumpower. The operation of MPPT can only be achieved when a tune able matching network is used as interface for load and the PV array. The main constituent components of a PV system are power stage and controller as shown in fig.3. The power stage is optimized using switch mode DC-DC converters (boost, buck-boost), employing pulse width control. The control parameter which is used for synchronizing the network for maximum extraction of power is duty ratio δ. The block diagram of PV system with MPPT control using boostpowerconverter is shown in fig. 3
cycle frequency equals 110 kHz. Fig. 6 shows the actuation cycle of the MOSFETs and the waveform generated in the primary of the transformer (V1). A charge/discharge time on the MOSFETs generate losses for there is voltage and current over them at the same time. To minimize these losses a Zero Voltage Switching (ZVS) technique is used. Therefore a time period in which the voltage at the primary of the transformer (V1) remains zero due to the use of this technique, so the switching time of the MOSFETs are different, depicted in Fig. 6.
Over the last several years, the Department of Defense has focused on conserving energy in order to enhance its combat capabilities. Renewable energy technologies, such as wind, solar, biomass, and others, have been explored so that the military can reduce its reliance on fossil fuels and improve its operational range. One of the components to this effort is solar photovoltaic (PV) technology. The purpose of this thesis is to demonstrate the importance of using a maximumpowerpointtracking (MPPT) algorithm to ensure that a PV system provides the most energy possible. Moreover, two different MPPT algorithms are presented in this thesis. An interleaved boostconverter controls the flow of power to a load and a 24-volt source. Also, it regulates the PV panel’s voltage and current so that the panel may operate at its maximumpowerpoint. A complete model of the solar panel, boostconverter, and control algorithms was created in Simulink in order to validate the system in simulation. The control algorithms were implemented using a field-programmable gate array so that the actual system could be tested and compared against the simulation. Experimental measurements validate the model and demonstrate that the MPPT algorithms perform as expected.
the output of the solar panel is also variable . The power constancy is obtained by using the DC-DC converters. The different DC-DC converters are the buck, boost and cuk converters are used based on the application requirements. The implementation of cuk converter for the power constancy which is also referred to maximumpowertracking method is used in direct control of power extraction . The MPPT techniques have various advantages which is discussed and compared and the significance are studied . The implementation of boostconverter is more common among the MPPT technique. The boostconverter output is comparatively efficient however; the extraction of power from the panel is considerable limited . In some applications it is necessary to have the buck and the boostconverter to obtain the various level of the power output, but the cost of two converters in a single system is not much efficient for the power generation . Further discussions have turned another new method of MPPT for the lower powersolar PV panels . In the proposed method, the MPPT involved uses the boostconverter which is controlled using the fuzzy logic controller. This fuzzy logic controller efficiently controls the boostconverter operation in obtaining the maximumpower from the solar PV panel.
ABSTRACT: A grid-connected photovoltaic (PV) power system with high voltage gain is proposed, and the steady- state model analysis and the control strategy of the system are presented. For a typical PV array, the output voltage is relatively low, and a high voltage gain is obligatory to realize the grid-connected function. The proposed PV system employs a ZVT-interleaved boostconverter with winding-coupled inductors and active-clamp circuits as the first power-processing stage, which can boost a low voltage of the PV array up to a high dc-bus voltage. Accordingly, an accurate steady-state model is obtained and verified by the simulation and experimental results, and a full-bridge inverter with bidirectional power flow is used as the second power-processing stage, which can stabilize the dc-bus voltage and shape the output current. Two compensation units are added to perform in the system control loops to achieve the low total harmonic distortion and fast dynamic response of the output current. The solar energy has several advantages for instance clean, unlimited, and its potential to provide sustainable electricity in area not served by the conventional power grid. The stand-alone system is used in off-grid application with battery storage. Its control algorithm must have an ability of bidirectional operation, which is battery charging and inverting. There are three main types of switched power converters respectively called Boost, Buck and BuckBoost. The proposed method is mathematically modeled and the results are analyzed. A similar prototype model is designed and the results are compared with the theoretical values.
For solar to be a competitive energy source it is extremely important to extract the maximumpower from each panel and lower the cost per kilowatt. It turns out that this is not as simple as just hooking a panel to a battery or grid; there are many variables that affect the performance of a panel, such as shade, shadows, and ambient temperature—thus the need for MPPT algorithms. Solar cells, like other silicon diodes, have an exponential transfer function from voltage to current. A small change in voltage results in a large change in current. Two important factors that have to be taken into account are the irradiation and the temperature. In general, I-V curve for a PV array is non – linear so a specific point on the curve Abstract: The power output of the solar array is dependent of the irradiance, temperature and internal properties of the materials used to make solar cells. These factors contribute in the position of the Maximumpowerpoint. Changes in atmospheric conditions affect directly the output of the solar panel. Therefore, there is a need to track the Maximumpowerpoint to ensure that the system delivers the maximumpower and the losses are reduced at any given time despite the change in temperature and irradiation throughout a day. The maximumpowerpointtracking(MPPT) of the PV output for all sunshine conditions is a key to keep the output power per unit cost low for successful PV applications. Several techniques have been proposed for maximumpowerpointtracking. The most commonly used technique for MPPT is the perturb and observe technique. MATLAB was used to simulate the Perturb and observe. The main aim will be to track the maximumpowerpoint of the photovoltaic module so that the maximum possible power can be extracted from the photovoltaic. The algorithms utilized for MPPT are generalized algorithms and are easy to model or used as a code. The algorithms are written in m files of MATLAB and utilized in simulation where the values of the irradiance and temperature were chosen based on the average values in Benue State. The solar cell is modeled using SIM Power Systems blocks.
A SEPIC converter consists of a switch, dual inductors, dual capacitors and a diode as shown in Figure 6 . SEPIC converter operates in balancing mode; the diode gets reversed biased when the switch is in an ON condition [ 31 ]. Inductor L1 starts storing the charge, whereas the capacitor C dc supports the load where the charge is transferred through inductor L 2 and capacitor Co. When the switch is in OFF state, the diode becomes forward biased. The energy that is stored in inductor L1 charges the capacitor Cdc . The current ripple during the buck mode operation of a SEPIC converter (during wind speed above rated value) is lower when compared with another conventional converter. The soft-computing commutation of a SEPIC converter can be enhanced when the system is included with a protective device like snubber circuit. The capacitor Cdc increases the gain of the SEPIC converter as they get charged during boost operation, which is reflected in the output during commutation period. The duty cycle and parasitic element of a SEPIC converter are designed as follows [ 32 ]:
A MPPT controller for solar system is modeled in this paper. The buckconverter is modeled using equation model approach, rather than circuit model approach. By developing model using equation modeling, the model could be modified or entendexd easily. To verify the developed equation model, the comparison to the existing circuilt model is done. The experiment result shows that the developed model is usited to the existing one. Moreover, a MPPT control model (P&O algorithm) is modeled and tested using several experiment data. The experiment results show that the overall model behaves like the real situation. Further, the properties of P&O algorithm such as the effect of the step value of perturbing duty cycle and the oscillation problem are well simulated.
ergy into electricity in a quantity dependent on the temperature difference across them and the electrical load applied. It is critical to track the optimum electrical operating point through the use of power electronic converters controlled by a maximumpowerpointtracking (MPPT) algorithm. The MPPT method based on the open-circuit voltage is arguably the most suitable for the linear electrical characteristic of TEGs. This paper presents an innova- tive way to perform the open-circuit voltage measure during the pseudonormal operation of the interfacing power electronic con- verter. The proposed MPPT technique is supported by theoretical analysis and used to control a synchronous Buck–Boostconverter. The prototype MPPT converter is controlled by an inexpensive mi- crocontroller, and a lead-acid battery is used to accumulate the harvested energy. Experimental results using commercial TEG devices prove that the converter accurately tracks the maximumpowerpoint during thermal transients. Precise measurements in the steady state show that the converter finds the maximumpowerpoint with a tracking efficiency of 99.85%.
This study has successfully developed a high-efficiency isolated single-input multiple-output buckconverter with step- down operational states, and this coupled-inductor-based converter was applied well to a single input power source plus two output terminals composed of an auxiliary battery module and a high-voltage dc bus. The experimental results reveal that the maximum efficiencies at the step-up state and the step-down state were measured to be 94% and 97%, respectively. The major contributions of the proposed converter are recited as follows:This topology adopts eight power switches to achieve the objectives of high-efficiency power conversion, electric isolation, bi-directional energy transmission, and various output voltage with different levels.The stray energy can be recycled by a clamped capacitor into the auxiliary battery module or high-voltage dc bus to ensure the property of voltage clamping. An auxiliary inductor is designed for providing the charge power to the auxiliary battery module and assisting the switch turned on under the condition of zero-voltage-switching (ZVS). The switch voltage stress at the step-up state is not related to the input voltage so that it is more suitable for a dc power conversion mechanism with different input voltage levels. The copper loss in the magnetic core can be greatly reduced as a full copper film with lower turns. This high-efficiency converter topology provides designers with alternative electric isolation choices for boosting a low-voltage power source to multiple outputs with different voltage levels, or reversely transmitting the energy of high-voltage dc bus efficiently. The auxiliary battery module used in this study also can be extended easily to other dc loads, even for different voltage demands, via the manipulation of circuit components design. The project can be extended into still more E-vehice devices to be connected. (at present we have connected 10 vehicles per phase). The control algorithms can be implemented as a micro controller based or DSP based systems. A hardware implementation of the full system may be worked out in future tenure of the project. The system may be implemented as a single chip system with SOC (system on chip) technology.
ABSTRACT: This paper presents the Modelling and simulation of Solar Photovoltaic Cell. Solar module temperature, solar radiation and it is effects on series resistance are taken into an account. This model is based on mathematical equations and is also represented through an equivalent circuit including a photocurrent source, a diode, a series resistor and a shunt resistor. This model allows the prediction of PV cell behaviour under different physical and environmental parameter. In this model, the function of solar temperature and solar radiation can also be used to take out the physical parameters for a given solar photovoltaic cell. The I-V and P-V characteristics are obtained and studied at various temperature values.
As renewable energy system has become widespread, PV systems are found to be easy solution for residential applications and low power generation. Modeling of accurate PV system has been a challenge. The model is designed based on the required specifications and from standard data sheets. For this thesis MPPT is implemented using boostconverter. In this paper comprehensive simulink PV model was designed, MPPT method coupled with DC/DC converter was simulated, single phase PLL based grid grid connected inverter was designed. The obtained results suit the domestic application of a rural area where energy requirement will be in kilowatts. The generated can utilize existing distribution system as the voltage output is synchronized with grid.
Abstract:- This article examines models of photovoltaic solar panels, the non-inverting Buck-boostconverter. The control strategy of the converter using the MPPT with the PI regulator is presented. The simulation is performed in the PSCAD- EMTDC software. The results show a good performance of the used models and controls. This article can be considered as an update of the models used and a complement in the control of the non- inverting Buck-boostconverter.
Abstract: Renewable energy sources are becoming important for the production of electricity used in residential, commercial and industrial applications. These resources include non- conventional sources like solar, wind, hydro, biogas, tidal and biomass. All these are contributing in the production of electrical energy and also help in reducing the pollution by reducing the green gas emissions which were one of the reasons to reduce the use of conventional sources. Out of all of the above, the source which is gaining an importance and maximum usage is a solar energy. The reason behind its extensive use is it is freely available, abundant, non-pollutingin nature and its conversion without involving any rotating device. Combining the two systems increases the performance and efficiency of a particular system. Hence to improve its performance and use by two-fold, a solar system can be integrated with thermal, hydro or wind power system. Also, a suitable converter topology will be used along with an appropriate control algorithm. Solar energy changes as per irradiance and temperature in a day also one factor which reduces the power output is the partial shedding in cells. This will alleviate the conversion efficiency of solar system (About 20%). Many conventional and advanced algorithms are used for getting the optimum output from a solar system. Now days to get optimum energy from a solar system, soft computing algorithms are used in a system which are called as operating pointtracking algorithms. This paper intended to emphasize on convertertopologies and a brief introduction of MPPT algorithms.
Maximumpowerpointtracking is used in solar PV energy conversion system to extract maximumpower from solar PV (Photovoltaic). MPPT algorithm is implemented in the control circuit of Power electronics DC-DC converters. The behavior of MPPT depends upon the type of the type of DC – DC converter used. The objective of this paper is to analyze the working of MPPT with buck-boost DC – DC converter. The simulation is study is done by using PSIM simulation software.
Various MPPT methods have been developed and implemented in the literature. They vary in complexity, sensors required, convergence speed, cost, range of effectiveness, hardware imple- mentation, and popularity. 9 Some of the most popular MPPT methods are incremental conduct- ance, perturbation and observation (P&O), fractional open-circuit voltage (FOCV), fractional short-circuit current (FSCC), and fuzzy logic control (FLC). 6–11 Among these MPPT methods, incremental conductance method offers a good performance under quick changes in weather con- ditions. Besides, it is also simple and can be implemented using low cost microcontroller. 6,9
The non-renewable energy sources are depleting fast and the solar energy has emerged as a future alternative energy source. It has limitations like less reliability, high installation cost and low conversion efficiency. In this paper, an efficient DC-DC boostconverter is designed to step up the voltage from the solar panel and supply to the load. A digital signal processor is used to implement the MPPT algorithm to extract the maximumpower from the solar panel at any instant of time. The circuit is simulated in MATLAB simulink and results are verified by hardware implementation. The power extracted can also be used to charge the batteries and can be used to supply power to loads when solarpower is unavailable.
Maximumpowerpointconverter is nothing but the dc to dc converter which helps for getting maximum output from the solar cell irrespective of the solar irradiation and temperature condition using the appropriate algorithm. There are various types of converter such as buckconverterboostconverter and buck-boostconverter. This converter is inserted between the solar cell and its load. Since there are various types of dc to dc converter hence it is quite difficult to understand which converter is suitable. Hence there should be an appropriate method which going to deal with these issues. The dc to dc converters are mostly work near about 100% efficiency and many designers have succeeded to get near about this efficiency.