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In this article, we focus on improving the performance and efficiency of photovoltaic systems. The main objective is to study and compare the performance of different MPPT methods, and to find the most efficient method (in terms of convergence speed, the MPP point where the oscillation is reduced), so that the generator of maximum power supplied by the photovoltaic can be extracted.. The main points involved in this research are: Modeling of the photovoltaic system Simulation of four MPPT algorithms. The simulation results are obtained using simulink in matlab.

In this article, we focus on improving the performance and efficiency of photovoltaic systems. The main objective is to study and compare the performance of different MPPT methods, and to find the most efficient method (in terms of convergence speed, the MPP point where the oscillation is reduced), so that the generator of maximum power supplied by the photovoltaic can be extracted.. The main points involved in this research are: Modeling of the photovoltaic system Simulation of four MPPT algorithms. The simulation results are obtained using simulink in matlab. [ABSTRACT FROM AUTHOR]

Compared to individual DC or AC microgrids, the Hybrid microgrids (HMGs) are more efficient and inexpensive due to eliminating of multiple DC-AC-DC conversions. In HMGs, where AC loads are supplied by DC link, load demand disturbance has direct negative effects on the DC link voltage. In this study, primary and secondary controllers are applied to realize suitable operation conditions and control the microgrid converters. Each converter has primary controller to compensate the demand power fluctuations. The secondary controller is also designed for extra demand varieties and sends the proper control signals for primary controllers. The expressed capability of primary controllers can be obtained by designing a simple and robust secondary controller. Hence, the effects of demand fluctuations are eliminated and the system is stabilized. The overall state space model of system is conducted for stability analysis. To demonstrate the proposed controller efficiency, a prototype HMG is modeled and simulated. The stability analysis reveals that the system is stable when the secondary controller tracks the error signal of DC link. Simulation results show that the proposed method could efficiently manage the AC side voltage under load fluctuations.

The demand for renewable energy has increased because it is considered a clean energy and does not result in any pollution or emission of toxic gases that negatively affect the environment and human health also requiring little maintenance, and emitting no noise, so it is necessary to develop this type of energy and increase its production capacity. In this research a design of maximum power point tracking (MPPT) control method using Neural Network (NN) for photovoltaic system is presented. First we design a standalone PV system linked to dc boost chopper with MPPT by perturbation and observation P&O technique, and then a design of MPPT by using ANN for the same system is presented. Comparative between two control methods are studied. The results explained in constant and adjustable weather settings such as irradiation and temperature. The results exposed that the proposed MPPT by ANN control can improve the PV array efficiency by reduce the oscillation around the MPP that accure in P&O method and so decreases the power losses. As well as decrease the the overshot that accure in transient response, and hence improving the performance of the solar cell. [ABSTRACT FROM AUTHOR]

This article deals with the PV based DC/DC boost chopper integrated nine level inverter. This topology requires 7 switches in minimum to obtain a nine level stepped wave output. So the main objective of this paper is to develop a 9 level AC output using PV based DC/DC boost chopper. In the case of conventional multi-level inverter, 16 switches were utilized and the number of sources needed was also more. Here the proposed system comprises of single PV panel and the switches used are also less. Also PV is integrated with DC/DC boost chopper is used to increase the source input level of the inverter. Using MATLAB platform, the proposed system is simulated with a resistive and inductive load. The similar results are obtained in prototype which validates the designed converter. [ABSTRACT FROM AUTHOR]

This paper proposes a novel Maximum Power Point Tracking (MPPT) control method of thermoelectric power generation for the constant load. This paper reveals the characteristics and the internal resistance of thermoelectric power module (TM). Analyzing the thermoelectric power generation system with boost chopper by state space averaging method, the output voltage and current of TM are estimated by with only single current sensor. The proposed method can seek without calculating the output power of TM in this proposed method. The basic principle of the proposed MPPT control method is discussed, and then confirmed by digital computer simulation using PSIM. Simulation results demonstrate that the output voltage can track the maximum power point voltage by the proposed MPPT control method. The generated power of the TM is 0.36 W when the temperature difference is 35 °C. This is well accorded with the V-P characteristics.

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Output of a three‐phase photovoltaic generator (PVG) is a function of sunlight irradiance, temperature, and three‐phase terminal voltage phasors. Three‐phase PVGs are largely connected to rural distribution systems feeders that are predominantly unbalanced. Models of PVGs that are only a function of sunlight irradiance and temperature disregarding unbalanced three‐phase terminal voltages phasors are simple to use with three‐phase power flow analysis but yield inaccurate solutions. Detailed three‐phase PVG models are complex and non‐linear, hence unsuitable for power flow analysis applications. This study proposes an artificial neural network (ANN) model to represent a PVG comprising photovoltaic panels, a boost chopper and a three‐phase inverter. Main advantages of the ANN model are that it can be readily used to model a PVG of any size and type, mathematical simplicity, high accuracy with unbalanced systems and computational speed. The model was tested with the unbalanced distribution system feeder from a Canadian utility. The results show that the ANN model of a PVG is computationally fast and more accurate than simple model that ignores unbalanced three‐phase terminal voltage phasors. In addition, simplicity of the proposed ANN model of PVG allows easy integration into commercial software packages such as PSS® SINCAL as reported in this study. [ABSTRACT FROM AUTHOR]

This paper presents the experimentation of Cascaded Multilevel Inverter (CMLI) for Photo Voltaic (PV) generator feeding an isolated load. For the improvement of PV system utilization, boost chopper interfaced CMLI configuration is developed under Multicarrier Sinusoidal Pulse Width Modulation (MCSPWM) control schemes. Boost chopper interfaced CMLI configuration boost up the PV panel voltage and generates high quality of AC power for domestic and drive load applications. The entire systems of PV, boost chopper and CMLI are simulated using SIMULINK and the results are validated. Prototype hardware model of single phase boost chopper interfaced 7-Level CMLI configuration is developed and its output illustrations are validated. [ABSTRACT FROM AUTHOR]

This paper proposes a novel Maximum Power Point Tracking (MPPT) control method of thermoelectric power generation for the constant load. This paper reveals the characteristics and the internal resistance of thermoelectric power module (TM). Analyzing the thermoelectric power generation system with boost chopper by state space averaging method, the output voltage and current of TM are estimated by with only single current sensor. The proposed method can seek without calculating the output power of TM in this proposed method. The basic principle of the proposed MPPT control method is discussed, and then confirmed by digital computer simulation using PSIM. Simulation results demonstrate that the output voltage can track the maximum power point voltage by the proposed MPPT control method. The generated power of the TM is 0.36 W when the temperature difference is 35 °C. This is well accorded with the V-P characteristics. [ABSTRACT FROM AUTHOR]

With the ever increasing concern on environmental pollution and energy crisis, generation of power from wind is developing very fast. In the proposed wind energy conversion system (WECS), a variable‐speed wind turbine, axial‐type permanent magnet generator (PMG), Z‐source inverter (ZSI) and sensorless maximum power point tracking (MPPT) controller are included. Although the conventional‐type induction generator has the advantage of robust construction and maintenance‐free operation, it has drawbacks like low‐power factor and need for an ac excitation source which is overcome by the PMG. To obtain fixed voltage and frequency, PMG‐generated voltage is fed to power converters. Conventionally the three stages of power conversion consist of rectifier, boost chopper and pulse‐width‐modulated inverter which reduce the efficiency, power quality and reliability of the overall WECS. To overcome these barriers of conventional system a two‐stage‐based direct‐drive WECS is proposed. The maximum power point for each speed is traced using sensorless MPPT controller, which estimates the rotor speed, by using a simple sensorless speed estimator which is given as the input to the MPPT controller. The proposed sensorless MPPT controller for direct‐drive WECS along with the ZSI is simulated in MATLAB/SIMULINK and the results are compared with experimental setup. [ABSTRACT FROM AUTHOR]

The integration of photovoltaic (PV) modules in buildings causes problems with shadows that can strongly reduce the energy produced by these systems. Moreover, most PV modules are designed for stand-alone applications that have output voltage adapted to lead batteries. Indeed, this historical sizing of PV modules can be discussed in the case of grid-connected systems. In this paper, a cascaded dc/dc converter based on boost chopper is proposed. First, the advantages and the limits of this topology will be shown. Second, this topology will be optimized to maximize the efficiency or minimize the volume. The originality of this optimization is that the converters' parameters and the arrangement of the PV cells are variable parameters. Indeed, the optimization is done on the entire system. To realize these optimizations, semiempiric models of losses and volumes of different components of a boost chopper were developed. The optimization uses a successive quadratic programming algorithm. Considering the optimization results over the whole range of the specifications, a flexible solution is developed and experimental results are presented. Finally, optimized topologies connected to several PV are evaluated at different situations of typical shadows. [ABSTRACT FROM AUTHOR]

A novel maximum power point tracking (MPPT) control for the operation of permanent magnet generator (PMG) based variable speed wind turbine is presented in this paper. The maximum power point tracking is required to get high efficiency for wind energy conversion system. The maximum power point for each wind speed is traced using a new method of Maximum Power Point Tracking algorithm. The rotating speed of permanent-magnet generator should be adjusted in the real time to capture maximum power from the wind. The proposed system consist of wind turbine, permanent-magnet generator, three-phase rectifier, boost chopper, inverter. The duty cycle of the boost chopper is the control parameter. To enhance the performance, PMG is operated at variable speed condition. The proposed system is simulated in MATLAB / SIMULINK and the results are compared with laboratory experimental setup. [ABSTRACT FROM AUTHOR]

A high-efficiency and high-power chopper based on a novel soft switching scheme QRAS (Quasi-resonant Regenerating Active Snubber) has been proposed in this paper. Operating efficiency of the proposed QRAS has been investigated by simulation and experiments. For the purposes of this study we fabricated a one-tenth prototype model and tested it under the rated load, light load, current discontinuous mode, and under operation out of the resonant stable operational region. The overall evaluation of these test results is provided and the possibility of implementation of an 80-kW practical model is demonstrated by these successful test results. In addition, as an approach to the next study, the feasibility of 8-kW SiC-QRAS is examined and a preliminary evaluation of the efficiency enhancement due to the use of silicon carbide (SiC) power devices is given based on successful experimental results. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 158(4): 68– 80, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20439 [ABSTRACT FROM AUTHOR]

This paper presents analysis of a high-power factor ac-dc converter with a boost converter operating in the discontinuous conduction mode (DCM) and the critical conduction mode (CRM). The converter can be expressed by a nonlinear differential equation for each mode. The equation in DCM is solved analytically by separating its variable (output voltage) into two terms of a ripple component and a direct component, and by linearizing the equation for the ripple component. On the other hand, the equation in CRM can be solved analytically. Furthermore, the source current waveform of the convener is expanded into the Fourier series. As a result, the output voltage, its ripple and the power factor of the converter in DCM and CRM are derived as a function of the circuit parameters, respectively, and verified experimentally. These equations exhibit clearly the effect of each circuit parameter of the converter and the difference between the converter in DCM and in CRM. The converter operating in CRM produces sinusoidal ac current with unity power factor. [ABSTRACT FROM AUTHOR]