Modelling, iterative procedure and simulation results for a monocrystalline solar cell

This paper focuses on the modelling and simulation for a photovoltaic system formed by monocrystalline solar modules. The objective is to find the parameters of the nonlinear I-V equation by adjusting the curve at three points: open circuit, maximum power, and short circuit. This paper brings a novel iterative procedure to find the value of diode ideality factor, series and equivalent shunt resistances. Simulation studies are carried out in order to uncover temperature dependence, solar radiation change, and output power variation. Finally, conclusions are duly drawn

Vertical axis wind turbine performance prediction: a new approach to the double multiple streamtube model

The vertical axis wind turbines (VAWT) have been suffering an increased acceptance for urban wind turbines integration in the future smart grid for decentralized generation (DG). The VAWT have several advantages over the more conventional horizontal axis wind turbines (HAWT): the smaller number of components; low sound emissions; their insensitivity to fast changes in wind flow direction; a lower architectural visual impact; the ability to operate closer to the ground; and others. But, the VAWT aerodynamic performance is more complex to simulate and predict due to its three dimensional operation. Several mathematical models have been presented to predict the VAWT performance, such as the double multiple streamtube (DMS) model. With the aim of presenting a tool to ease the study of complex shaped VAWTs, being at the same time able to be easily integrated in computational design tools, a new approach to the DMS model is presented in this paper

Simulation of the effect of shading on monocrystalline solar module technology under hot spot condition

This paper focuses on the monocrystalline PV module technology subjected to operation conditions with some cells partially or fully shaded. A shaded cell under hot-spot condition operating at reverse bias are dissipating power instead of delivering power. A thermal model allows analyzing the temperature increase of the shaded cells of the module under hot-spot condition with or without protection by a bypass diode. A comparison of the simulation results for a monocrystalline PV module without shading and with partial or full shading is presented

Wireless Energy Transfer with Three-Phase Magnetic Field System: Experimental Results

In this paper a three-phase magnetic field system is applied to the wireless power transfer system. The research is directed not only to the distribution of the magnetic field but to optimize the energy transfer efficiency, and to reduce the electromagnetic field influence to the surroundings. The development of the future intelligent transportation system depends on the electric mobility, namely, the individual or the public electric vehicles. It is crucial to achieve progress in the batteries and the battery charging, especially through a wireless power transfer technology. The study of the magnetic field is important in this technology. The energy transfer efficiency depends of the alignment, the size of the coils, the spatial orientation of the magnetic field, the detachment and the tilt between the windings

Fractional control of an offshore wind system

This paper presents a simulation on a way to improve the ability of an offshore wind system to recover from a fault in the rectifier converter. The system comprises a semi-submersible platform, a variable speed wind turbine, a synchronous generator with permanent magnets (PMSG), and a five-level multiple point diode clamped converter. The recovery is improved by shielding the DC link of the converter during the fault using as further equipment a redox vanadium flow battery. A fractional PI controller is used for the PMSG and the converter

Darrieus vertical axis wind turbines: methodology to study the self-start capabilities considering symmetric and asymmetric airfoils

The rapid growth of wind power generation and the need for a smarter grid with decentralized energy generation has increased the interest in vertical axis wind turbines (VAWT), especially for the urban areas. For the urban areas the VAWT offer several advantages over the horizontal ones, so their acceptance is rising. The lift-type VAWT (Darrieus wind turbines) have a natural inability to self-start without the help of extra components. The existing methodologies are usually used to optimize the wind turbine performance, but not its ability to self-start. Indeed, studying the aerodynamic behavior of blade profiles is a very complex and time-consuming task, since blades move around the rotor axis in a three-dimensional aerodynamic environment. Hence, a new methodology is presented in this paper to study the self-start ability of VAWT, which offers a substantial time reduction in the first steps of new blade profiles development. Both symmetrical and asymmetrical airfoils are targeted in our study, presenting comprehensive results to validate our methodology

Optimal Scheduling of Joint Wind-Thermal Systems

This paper is about the joint operation of wind power with thermal power for bidding in day-ahead electricity market. Start-up and variable costs of operation, start-up/shut-down ramp rate limits, and ramp-up limit are modeled for the thermal units. Uncertainty not only due to the electricity market price, but also due to wind power is handled in the context of stochastic mix integer linear programming. The influence of the ratio between the wind power and the thermal power installed capacities on the expected profit is investigated. Comparison between joint and disjoint operations is discussed as a case study

Optimal Bidding Strategies of Wind-Thermal Power Producers

This paper addresses a stochastic mixed-integer linear programming model for solving the self-scheduling problem of a thermal and wind power producer acting in an electricity market. Uncertainty on market prices and on wind power is modelled via a scenarios set. The mathematical formulation of thermal units takes into account variable and start-up costs and operational constraints like: ramp up/down limits and minimum up/down time limits. A mixed-integer linear formulation is used to obtain the offering strategies of the coordinated production of thermal and wind energy generation, aiming the profit maximization. Finally, a case study is presented and results are discussed

Distributed generation control using modified PLL based on proportional-resonant controller

Due to the increasing necessity for electrical demand, the microgrids (MGs) based on distributed generations (DGs) within power electronic interfaces are being extended to improve the traditional network control. One of the common ways to achieve the power sharing among the resources on an islanding MG is to use droop control approach, performing based on proportional-integrator (PI) controllers. However, due to the effect of feeder impedance, obtaining the reactive power sharing using this method is not accurate and leads to overload in some DGs, results in the output terminal voltage of each DG go out of the allowable range. The second problem arises when the frequency measurement is not performed precisely, leading inaccurate active power sharing, which can be solved by using an improved phase locked loop (PLL). Therefore, the purpose of this paper is to propose an applicable and simple approach based on the use of conventional droop characteristics and a proportional-resonant (PR) controller in a DG control system. Due to the load changes in the microgrid and other contingencies, the proposed PLL-based controller is able to represent supreme performance with low error in several case studies

Coordinated Scheduling of Wind-Thermal Gencos in Day-Ahead Markets

This paper presents a stochastic mixed-integer linear programming approach for solving the self-scheduling problem of a price-taker thermal and wind power producer taking part in a pool-based electricity market. Uncertainty on electricity price and wind power is considered through a set of scenarios. Thermal units are modeled by variable costs, start-up costs and technical operating constraints, such as: ramp up/down limits and minimum up/down time limits. An efficient mixed-integer linear program is presented to develop the offering strategies of the coordinated production of thermal and wind energy generation, aiming to maximize the expected profit. A case study with data from the Iberian Electricity Market is presented and results are discussed to show the effectiveness of the proposed approach