基于DSP的光伏并网逆变系统的设计

介绍了基于DSP的光伏并网逆变系统的设计。系统采用TMS320F2407作为主控芯片,通过最大功率跟踪,使太阳电池动态工作在最大功率点上。运用电流预估计原理使输出性能得到提高,通过软件锁相使输出电流同步跟踪电网电压相位,并具有电网掉电识别、过流、欠压和监控等功能,保证了光伏并网发电的安全运行,并具有远程通讯功能。     

Augmenting rooftop solar energy penetration ratio with secondary distribution network using smart inverter for maximum power transfer capacity for subordinate grid- A review

A rooftop photovoltaic power station, or rooftop PV system, is a photovoltaic system that has its electricity-generating solar panels mounted on the rooftop of a residential or commercial building or structure. The various components of such a system include photovoltaic modules, mounting systems, cables, solar inverters, and other electrical accessories. Rooftop mounted systems are small compared to ground-mounted photovoltaic power stations with capacities in the MW (megawatt) range. With the significant improvement of Rooftop Solar Photovoltaic Energy System (RSPES) among various Renewable Energy Systems, the major issues, effects, and several operational characteristics of the rooftop solar PVs in the Distribution System (DS) with Low Power Utility Network are actively being studied and investigated by global researchers and operation engineers. The most important objective of various researches about RSPES is to design a Power System with Optimal Maximum Power Transfer Capacity (MPTC). These review papers analyze the performance of Secondary Distribution System integrated to grid with Smart Inverter with or without the presence of Distribution Generation (DG) units. The effects caused by the penetration of Rooftop Solar Photovoltaic (PV) units in the Distribution Equipment (DE) are detailed in this paper with various research techniques. With the consideration of different objective constraints, Optimization techniques are utilized for solving minimization problems of objectives such as Size, Area, Operational Characteristics, Energy Loss, Cost of Installation, Generation Cost, Peak Load, Reverse Power Flow, and maximization problems of objectives such as PV power generation, Energy Saving Capability, Electricity Energy Mix, etc.. The various optimization techniques and frameworks for improving the performance of Power System and their corresponding results are demonstrated in this paper. This paper reviews totally 42 related researches done on the different phases of Optimization based Rooftop Solar PV system in the period between 2015 and 2017. This review summarizes the evaluation of the i) Solar rooftop energy with effects of increase in penetration; ii) The performance of efficient secondary distribution system with grid integrated smart inverter; iii) Algorithms based on optimization for solving the objectives in rooftop solar PV system are investigated.     

Techno‐economic and environmental analysis for grid interactive solar photovoltaic power system of Lakshadweep islands

The Lakshadweep group of islands in Arabian Sea is one of the two major groups of islands in India. In these islands the main source of electricity is diesel generators, the diesel being transported from the main land to produce over 9 MW of electricity. Considering the remoteness of the island and the polluting nature of the existing plants, it is desirable to adopt a strategy to utilize available potential of non‐polluting renewable energy sources for these ecologically sensitive islands. A techno economic and environmental analysis for grid interactive solar photovoltaic power system of Union Territory of Lakshadweep islands is presented. This paper also examines the pollution aspect of power generation through Diesel Generator set and highlights the environmental benefits in using solar energy. Experiences of grid interactive solar photovoltaic power system installed recently in different islands are discussed and suggestions have been made for improving its efficiency and performance. Copyright © 2004 John Wiley & Sons, Ltd.     

Estimating the manufacturing cost of purely organic solar cells

In this paper we estimate the manufacturing cost of purely organic solar cells. We find a very large range since the technology is still very young. We estimate that the manufacturing cost for purely organic solar cells will range between $50 and $140/m². Under the assumption of 5% efficiency, this leads to a module cost of between $1.00 and $2.83/W_p. Under the assumption of a 5-year lifetime, this leads to a levelized cost of electricity (LEC) of between 49¢ and 85¢/kWh. In order to achieve a more competitive COE of about 7¢/kWh, we would need to increase efficiency to 15% and lifetime to between 15-20 years.     

Optimal operation of DC smart house system by controllable loads based on smart grid topology

From the perspective of global warming mitigation and depletion of energy resources, renewable energy such as wind generation (WG) and photovoltaic generation (PV) are getting attention in distribution systems. Additionally, all-electric apartment houses or residence such as DC smart houses are increasing. However, due to the fluctuating power from renewable energy sources and loads, supply-demand balancing of power system becomes problematic. Smart grid is a solution to this problem. This paper presents a methodology for optimal operation of a smart grid to minimize the interconnection point power flow fluctuation. To achieve the proposed optimal operation, we use distributed controllable loads such as battery and heat pump. By minimizing the interconnection point power flow fluctuation, it is possible to reduce the electric power consumption and the cost of electricity. This system consists of photovoltaic generator, heat pump, battery, solar collector, and load. To verify the effectiveness of the proposed system, results are used in simulation presented.     

Grid‐connected photovoltaic power plants: A review of the recent integration requirements in modern grid codes

The high integration of photovoltaic power plants (PVPPs) has started to affect the operation, stability, and security of utility grids. Thus, many countries have established new requirements for grid integration of solar photovoltaics to address the issues in stability and security of the power grid. In this paper, a comprehensive study of the recent international grid codes requirement concerning the penetration of PVPPs into electrical grids is provided. Firstly, the paper discusses the trends of PVPPs worldwide and the significance of improving grid codes' requirements. In addition, the comparison of common requirements covered in the majority of international grid codes considers high‐ and low‐voltage ride‐through capabilities, voltage and frequency regulation, and active and reactive power support requirements. Finally, a broad discussion on the compliance technology challenges and global harmonization of international grid codes that the PVPPs have to address is presented. The study summarizes the most recent international regulation regarding photovoltaic integration and research findings on the compliance of these regulations and proposed recommendations for future research. It also can assist power system operators to compare their existing requirements with other universal operators or establish their own regulations for the first time. Additionally, this research assists photovoltaic manufacturers and developers to get more accurate understanding from the recent global requirements enforced by the modern grid codes.     

The investment costs of electrolysis – A comparison of cost studies from the past 30 years

Water electrolysis is a promising technology for storing surplus energy from intermittent renewable energy sources in the form of hydrogen. The future investment costs of water electrolysis represent one key challenge for a hydrogen-based energy system. In this work, a literature review was conducted to evaluate the published data on investment costs and learning rates for PEM and alkaline electrolyzers from the 1990s until 2017 and the years beyond. The collected data are adjusted for inflation and specified in €₂₀₁₇ per kW-output using the higher heating value (HHV). R&D efforts have led to impressive cost reductions in the observed period, especially for PEM technology, while cost reductions for alkaline technology have also been decent. The overall spread of the cost estimations in the 1990s was in a range between 306 and 4748 €₂₀₁₇/kW_HHV-Output. Today's estimations for future investment costs (through 2030) for both technologies are narrowed towards values of 397 and 955 €₂₀₁₇/kW_HHV-Output. Higher automation, mass production, larger cell areas, market penetration and technology development will all have a further impact on the investment costs.     

Minimisation of the cost of generated electricity from dye-sensitised solar cells using numerical analysis

Arrays of thin-film solar cells based on dye-sensitised nanocrystalline oxides (DSC) promise low-cost electricity especially where continuous direct insolation is unavailable. However, the optimisation of arrays of DSC is not straightforward because of the lower power levels obtained and the corresponding increased stringency needed when calculating the production tolerances permissible in the individual cells. This paper describes the first stage of project to devise and build a DSC array simulator driven solely by a phenomenological model of individual DSC behaviour at the level of infinitesimal cells. The simulator numerically extrapolates this behaviour to real finite cells and thence to a real physical array. In the process it is observed that optimisation of infinitesimal cells is only possible when the size of the real cell is first decided, and that the relationship between the conducting oxide transparency and electrical resistance is critical for the optimisation to be effective. The results obtained using the simulator are compared with the behaviour of real test cell assemblies manufactured by STI, a DSC Licensee, and are found to be in good agreement. Their effects on the costs of delivered power are discussed.     

Optimization of a solar photovoltaic thermal (PV/T) water collector based on exergy concept

In this paper, the optimization of a solar photovoltaic thermal (PV/T) water collector which is based on exergy concept is carried out. Considering energy balance for different components of PV/T collector, we can obtain analytical expressions for thermal parameters (i.e. solar cells temperature, outlet water temperature, useful absorbed heat rate, average water temperature, thermal efficiency, etc.). Thermal analysis of PV/T collector depends on electrical analysis of it; therefore, five-parameter current–voltage (I–V) model is used to obtain electrical parameters (i.e. open-circuit voltage, short-circuit current, voltage and current at the point which has maximum electrical power, electrical efficiency, etc.). In order to obtain exergy efficiency of PV/T collector we need exergy analysis as well as energy analysis. Considering exergy balance for different components of PV/T collector, we obtain the expressions which show the exergy of the different parts of PV/T collector. Some corrections have been done on the above expressions in order to obtain a modified equation for the exergy efficiency of PV/T water collector. A computer simulation program has been developed in order to obtain the amount of thermal and electrical parameters. The simulation results are in good agreement with the experimental data of previous literature. Genetic algorithm (GA) has been used to optimize the exergy efficiency of PV/T water collector. Optimum inlet water velocity and pipe diameter are 0.09 m s⁻¹, 4.8 mm, respectively. Maximum exergy efficiency is 11.36%. Finally, some parametric studies have been done in order to find the effect of climatic parameters on exergy efficiency.     

Spillover effects of distribution grid tariffs in the internal electricity market: An argument for harmonization?

In many countries, distribution grid tariffs are being reformed to adapt to the new realities of an electricity system with distributed energy resources. In Europe, legislative proposals have been made to harmonize these reforms across country borders. Many stakeholders have argued that distribution tariffs are a local affair, while the European institutions argued that there can be spillovers to other countries, which could justify a more harmonized approach. In this paper, we quantify these spillovers in a simplified numerical example to give insight and an order of magnitude. We look at different scenarios, and find that the spillovers can be both negative and positive. To be able to quantify these effects, we developed a long-run market equilibrium model that captures the wholesale market effects of distribution grid tariffs. The problem is formulated as a non-cooperative game involving consumers, generating companies and distribution system operators in a stylized electricity market.     

The impact of state policy on deployment and cost of solar photovoltaic technology in the U.S.: A sector-specific empirical analysis

Using a panel database for 27 programs in 16 U.S. states over 1998–2009, we assess the impact of 12 state-level policies on the cost and deployment of solar photovoltaic (PV) technologies for two sectors defined by system sizes: residential (<10 kW) and commercial (10−100 kW). We first examine the impact of policies on the deployment of solar PV. We show that cash incentives increase the deployment of commercial systems. We also show that interconnection standards potentially promote the deployment of residential systems, whereas property tax incentives potentially foster the deployment of commercial systems. We next examine the impact of policies on the cost of solar PV, and show that the key policies have different effects on costs. The cost of residential systems declines faster if there are cash or property tax incentives in place, whereas the presence of interconnection standards potentially accelerates the decline in commercial system costs. Further, states with a renewable portfolio standard see residential system costs potentially declining slower than states without such a policy. As solar PV is at the brink of becoming cost competitive, our findings assist regulators in fine-tuning their set of support tools.     

并网风电机组输出电能闪变和谐波指标的比较与分析

对根据IEC 61400-21标准进行测试的四款风电机组,即750 kW定桨失速型机组、2 MW变速恒频全馈机组、2.5 MW变速恒频双馈机组和运达（WD77-1500 A/1500 kW）变速恒频双馈机组的电能质量测试和评估报告进行了分析,通过比较风电机组闪变的测量值、谐波电流值,可对各种风电机组在不同方面的性能有一定的了解。     

核动力装置蒸汽发生器初步设计优化研究

本文以蒸汽发生器总重量最小为目标函数,提出了一个核动力推进装置蒸汽发生器初步设计优化方法．给出了优化结果和灵敏度分析结果．计算表明该方法是有效的．     

Design of a robust and efficient power electronic interface for the grid integration of solar photovoltaic generation systems

Nowadays, the penetration of photovoltaic (PV) solar power generation in distributed generation (DG) systems is growing rapidly. This condition imposes new requirements to the operation and management of the distribution grid, especially when high integration levels are achieved. Under this scenario, the power electronics technology plays a vital role in ensuring an effective grid integration of the PV system, since it is subject to requirements related not only to the variable source itself but also to its effects on the stability and operation of the electric grid. This paper proposes an enhanced interface for the grid connection of solar PV generation systems. The topology employed consists of a three-level cascaded Z-source inverter that allows the flexible, efficient and reliable generation of high quality electric power from the PV plant. A full detailed model is described and its control scheme is designed. The dynamic performance of the designed architecture is verified by computer simulations.     

Optimization of a photovoltaic pumping system based on the optimal control theory

This paper suggests how an optimal operation of a photovoltaic pumping system based on an induction motor driving a centrifugal pump can be realized. The optimization problem consists in maximizing the daily pumped water quantity via the optimization of the motor efficiency for every operation point. The proposed structure allows at the same time the minimization the machine losses, the field oriented control and the maximum power tracking of the photovoltaic array. This will be attained based on multi-input and multi-output optimal regulator theory. The effectiveness of the proposed algorithm is described by simulation and the obtained results are compared to those of a system working with a constant air gap flux.     

A methodology to select the experimental plant instrumentation based on an a priori analysis of measurement errors and instrumentation cost

An experimental apparatus for evaluating carbon dioxide local heat transfer coefficients during flow boiling has been set up at University of Naples Federico II. In this paper, the local heat transfer coefficient measured is evaluated relative to the measurement error, varying the type and costs of the instrumentation. The analytical analysis has been performed prior to construction of the test facility. The main aim of the work is to provide a methodology that allows one to reach the best compromise between measurement accuracy and financial resources in the selection of the instrumentation.     

Analytical model for predicting the performance of photovoltaic array coupled with a wind turbine in a stand-alone renewable energy system based on hydrogen

We present the results of an analysis of the performance of a photovoltaic array that complement the power output of a wind turbine generator in a stand-alone renewable energy system based on hydrogen production for long-term energy storage. The procedure for estimating hourly solar radiation, for a clear sunny day, from the daily average solar insolation is also given. The photovoltaic array power output and its effective contribution to the load as well as to the energy storage have been determined by using the solar radiation usability concept. The excess and deficit of electrical energy produced from the renewable energy sources, with respect to the load, govern the effective energy management of the system and dictate the operation of an electrolyser and a fuel cell generator. This performance analysis is necessary to determine the effective contribution from the photovoltaic array and the wind turbine generator and their contribution to the load as well as for energy storage.     

Prioritizing the alternatives of the natural gas grid conversion to hydrogen using a hybrid interval rough based Dombi MARCOS model

The aim of this study is to disclose an integrated multi-criteria decision making model as an instrument able to be used for hydrogen gas grid development via natural gas network conversion by considering four main criteria and sixteen sub-criteria. The proposed model consists of two stages using interval rough based Dombi MARCOS (Measurement Alternatives and Ranking according to the COmpromise Solution) method. In the first stage, the interval rough Bonferroni logarithmic methodology of additive weights is applied for determining the weight coefficients. In the second stage, the improved interval rough MARCOS method is used to rank the alternatives. A case study for hydrogen gas grid development in Romania set out the applicability and effectiveness of the proposed model. The proposed model is analysed from various points of view so that it can be used effectively in reality not only theoretically. This study analyzes four technical alternatives for hydrogen gas grid development. The results show that the conversion for mixtures natural gas with hydrogen a transporting a mix of gases is the best alternative among the four alternatives, for the next period and in the specific context described by this study. The current technical-economic criteria are rather a constraint when discussing gas infrastructures. For choosing a sustainable solution, a major role comes for decision makers, along with the desire to pay fairly from the consumer.     

基于智能电网的电动汽车充放电分时电价及引导策略

为了以绿色、环保能源满足全球可持续发展的需求,可再生能源和电动汽车在全球范围内受到广泛推崇.在此情形下,高比例可再生能源发电和大规模电动汽车无序分散接入电网必将导致供求曲线的不稳定.为此,借助云存储技术和智能电网,提出了一种基于供求曲线的电动汽车充放电分时电价,并在制定充放电价格时考虑充电站的空闲率.以实现充电站和用户...     

State-of-art review of the optimization methods to design the configuration of hybrid renewable energy systems (HRESs)

The current research aims to present an inclusive review of latest research works performed with the aim of improving the efficiency of the hybrid renewable energy systems (HRESs) by employing diverse ranges of the optimization techniques, which aid the designers to achieve the minimum expected total cost, while satisfying the power demand and the reliability. For this purpose, a detailed analysis of the different classification drivers considering the design factors such as the optimization goals, utilized optimization methods, grid type as well as the investigated technology has been conducted. Initial results have indicated that among all optimization goals, load demand parameters including loss of power supply probability (LPSP) and loss of load probability (LLP), cost, sizing (configuration), energy production, and environmental emissions are the most frequent design variables which have been cited the most. Another result of this paper indicates that almost 70% of the research projects have been dedicated towards the optimization of the off-grid applications of the HRESs. Furthermore, it has been demonstrated that, integration of the PV, wind and battery is the most frequent configuration. In the next stage of the paper, a review concerning the sizing methods is also carried out to outline the most common techniques which are used to configure the components of the HRESs. In this regard, an analysis covering the optimized indicators such as the cost drivers, energy index parameters, load indicators, battery’s state of charge, PV generator area, design parameters such as the LPSP, and the wind power generation to load ratio, is also performed.