Showing papers on "Grid-connected photovoltaic power system published in 1999"

Wind and Solar Power Systems

Abstract: Introduction Industry Overview Incentives for Renewables Utility Perspective References Wind Power Wind in the World The U.S.A. Europe India Mexico Ongoing Research and Development References Photovoltaic Power Present Status Building Integrated pv Systems pv Cell Technologies pv Energy Maps References Wind Speed and Energy Distributions Speed and Power Relations Power Extracted from the Wind Rotor Swept Area Air Density Global Wind Patterns Wind Speed Distribution Wind Speed Prediction Wind Resource Maps References Wind Power System System Components Turbine Rating Electrical Load Matching Variable-Speed Operation System Design Features Maximum Power Operation System Control Requirements Environmental Aspects References Electrical Generator Electromechanical Energy Conversion Induction Generator References Generator Drives Speed Control Regions Generator Drives Drive Selection Cut-Out Speed Selection References Solar Photovoltaic Power System The pv Cell Module and Array Equivalent Electrical Circuit Open Circuit Voltage and Short Circuit Current i-v and p-v Curves Array Design Peak Power Point Operation pv System Components References Solar Thermal System Energy Collection Solar II Power Plant Synchronous Generator Commercial Power Plants References Energy Storage Battery Types of Batteries Equivalent Electrical Circuit Performance Characteristics More on Lead-Acid Battery Battery Design Battery Charging Charge Regulators Battery Management Flywheel Compressed Air Superconducting Coil References Power Electronics Basic Switching Devices AC to DC Rectifier DC to AC Inverter Grid Interface Controls Battery Charge/Discharge Converters Power Shunts References Stand-Alone System pv Stand-Alone Electric Vehicle Wind Stand-Alone Hybrid System System Sizing Wind Farm Sizing References Grid-Connected System Interface Requirements Synchronizing with Grid Operating Limit Energy Storage and Load Scheduling Utility Resource Planning Tool References Electrical Performance Voltage Current and Power Relations Component Design for Maximum Efficiency Electrical System Model Static Bus Impedance and Voltage Regulation Dynamic Bus Impedance and Ripple Harmonics Quality of Power Renewable Capacity Limit Lightning Protection National Electrical Code on Renewable Power Systems References Plant Economy Energy Delivery Factor Initial Capital Cost Availability and Maintenance Energy Cost Estimates Sensitivity Analysis Profitability Index Hybrid Economics References The Future World Electricity Demand to 2015 Wind Future pv Future Declining Production Costs Market Penetration Effect of Utility Restructuring References Further Reading Appendix 1 Appendix 2 Acronyms Conversion of Units Index

Photovoltaic Systems Engineering

Abstract: Background.- The Sun.- Introduction to PV Systems.- PV System Examples.- Cost Considerations.- Mechanical Considerations.- Stand-Alone PV Systems.- Utility Interactive PV Systems.- Externalities and Photovoltaics.- The Physics of Photovoltaic Cells.- Present and Proposed PV Cells.

New approach to photovoltaic arrays maximum power point tracking

Abstract: The present trend for commercial telecommunication and scientific satellites is the utilization of standard platform, characterized by a high level of flexibility and reduced nonrecurring costs. One of the areas where flexibility is mandatory is the electrical primary power subsystem, due to the impact on solar array configuration and dimensions and on power conditioning unit. Use of the maximum power point tracker (MPPT) concept allows optimization of the above mentioned subsystem, maximizing the power transfer from the photovoltaic generator. The purpose of the paper is to present a new MPPT approach that allows minimization of the drawback caused by the intrinsic capacitance of the photovoltaic array (generally neglected) giving the possibility of operation with a large degree of freedom, independent from the converter topology and photovoltaic power generator, electrical network and technology.

Improving grid behaviour

Abstract: In this paper, the author describes how the inglorious Summer-of-1996 blackouts taught the Western USA to improve emergency grid control and protection and to sharpen power network simulation techniques.

An inverter using buck-boost type chopper circuits for popular small-scale photovoltaic power system

Abstract: This paper presents a newly developed transformer-less single phase inverter for a photovoltaic (PV) power system. The proposed system consists of two sets of a PV array and buck-boost type chopper circuit. However, it is afraid that the system has lower "using rate" of PV energy than that of the ordinary PV system, as each PV array is only operated in the half duration of the AC power frequency. In this paper, it is also discussed how to increase this "using rate" by varying the connected capacitor between PV array terminals. The perturbation and observation method is adapted to the maximum power tracking in our PV systems. We adopt the wavelet transform to detect a power outage. The experimental data shows that this new inverter can supply AC power to the utility grid line with the power factor nearly unity.

Photovoltaic power generating structure

Abstract: There is disclosed a photovoltaic power generating structure in which a solar cell module is arranged on a base member, wherein a closed space portion cut off from the air is provided between the base member and the solar cell module. Thus, there can be provided the photovoltaic power generating structure which can be easily constructed at a low installation cost, can maintain a good output as a photovoltaic power generating system, is excellent in environmental resistance, and can improve a fire-proof performance.

Usage of the solar energy from the photovoltaic panels for the generation of electrical energy

Abstract: This paper presents the analysis of a static conversion system for treatment of the solar energy from photovoltaic panels. This system is interconnected with the mains power supply, contributing to the generation of the electrical energy. The power structure is composed by a current-fed push-pull converter, a buck converter and a current inverter. The main features of the system are: simple control strategy, robustness, lower harmonic distortion of the current and natural isolation. The principle of operation, design procedure and experimental results are presented.

Solar battery controller and solar power generating device

Abstract: PROBLEM TO BE SOLVED: To provide a solar power generating device having a maximum power point tracking function capable of accurately detecting a maximum power point even when the output power-output voltage characteristic of a solar battery has a plurality of peaks without making the output voltage and output power of the solar battery fluctuate needlessly. SOLUTION: An output power-output voltage characteristic detecting means CD1 provided with a solar battery PV1 having the same environmental condition as a main solar battery PV2 is provided apart from a main generation circuit. Then, an output voltage controlling means CT1 obtains the numerical data of the output power-output voltage characteristic of the battery PV1 for characteristic detection by turning a switch SW on or off and detects a maximum power point. Then, control signals S1a to S1d are given to respective transistors T1 to T4 of a voltage type inverter IV1 so that the main solar battery PV2 can generate a voltage value corresponding to the detected maximum power point.

A transformer-less inverter using buck-boost type chopper circuit for photovoltaic power system

Abstract: This paper presents a newly developed transformer-less single phase inverter for a photovoltaic (PV) power system. The proposed system consists of two sets of PV array and buck-boost type chopper circuit. However, the system has lower "using rate" of PV energy than that of the ordinary PV system, as each PV array is only operated in the half duration of the AC power frequency. In this paper, it is also discussed how to increase this "using rate" by varying the connected capacitor between PV array terminals. The simulation and experimental data show that the proposed inverter can supply the AC power to a utility grid line with the power factor nearly unity.

Photovoltaic power generating set

Abstract: PROBLEM TO BE SOLVED: To enable a photovoltaic power generating set to make uninterruptible power feed to an important load, without causing instantaneous interruptions caused system power failure, etc., by effectively utilizing the power generated from a solar battery as much as possible. SOLUTION: A photovoltaic power generating set is provided with an inverter (first inverter) 17 connected with a solar battery 15, another inverter (second inverter) 22 connected with a rectifier 19 and a battery 20, and an input bridging switch 23. The set is also provided with an AC output circuit 24, which always feeds the AC power outputted from the inverters 17 and 22 to a load 28 and a control circuit 30, which controls the operation of the inverters 17 and 22 and the opening/closing of the switch 23. The control circuit 30 is provided with a normal operation control means, which operates the inverter 17 by controlling the tracking of the maximum power point of the solar battery 15 and the inverter 22 by performing CVCF control through the means of opening the switch 23, and an insufficient operation control means which operates the inverters 17 and 22 by performing CVCF control by using the solar battery 15, rectifier 19, and battery 20 as a common DC power source, due to the power feed becoming insufficient due to the CVCF control. COPYRIGHT: (C)2001,JPO

Electricity storing system and electric power feeding system

Abstract: PROBLEM TO BE SOLVED: To make it possible to easily install an electricity storing system in a solar cell power generating system at low cost later on. SOLUTION: This electricity storing system is connected to a solar cell power generating system provided with a solar cell power converter 2 having an inverter 3 and a control circuit 4 and solar cells 1. This system receives and stores DC electric power from a converter 19 that converts AC electric power at night of a commercial power source 10 into DC electric power. Provided with a secondary battery 13 that feeds the stored electric power to the inverter 3, it also controls the supply of electric power from the secondary battery 13 to the inverter 3 by a control circuit 32.

Stability of a pump storage hydro-power station connected to a power system

Abstract: The operational flexibility of pumped storage hydropower stations means that they are often used for the control of power system frequency. When used in this role, the response of the power station is determined by the behaviour of its governor, the stiffness of the connected grid and the interaction between the governor and the grid. An investigation into the governor settings at Dinorwig power station in the UK has been undertaken in order to establish the optimum governor settings for different loading conditions, providing as close to an ideal response as possible without endangering the stability of system frequency control. The gain and phase margins of the open loop transfer function of the system were examined to determine the stability of the power system, and the effect of the droop settings and the grid size are included in the study. Information on stability of the power station is presented for a variety of operating and grid conditions.

A Solar Dynamic Power Option for Space Solar Power

Abstract: A study was performed to determine the potential performance and related technology requirements of Solar Dynamic power systems for a Space Solar Power satellite. Space Solar Power is a concept where solar energy is collected in orbit and beamed to Earth receiving stations to supplement terrestrial electric power service. Solar Dynamic systems offer the benefits of high solar-to-electric efficiency, long life with minimal performance degradation, and high power scalability. System analyses indicate that with moderate component development, SD systems can exhibit excellent mass and deployed area characteristics. Using the analyses as a guide, a technology roadmap was -enerated which identifies the component advances necessary to make SD power generation a competitive option for the SSP mission.

Increased Efficiency in the Conversion of Solar Energy to Electric Power

Abstract: This article presents a new dual purpose technique to improve photovoltaic (PV) array efficiency and has a great effect for the net power saving. To realize the first aim, the forced-air cooling technique with the optimal flow rate for PV array is designed and implemented. The decreasing rate in cell temperature has a direct proportional relation with PV efficiency. At the same time, the output hot air is very useful for air conditioning houses and for heating water systems, especially in remote areas. The electrical performance of PV modules also was studied. Finally, the effect of power saving was cleared and the economical results were achieved.

Solar battery module, solar battery array, photovolatic power plant, and method of specifying fault of solar battery module

Abstract: PROBLEM TO BE SOLVED: To specify a faulty solar battery module, by detecting the fault regardless of the constitution of a solar battery array or the fault mode of a solar battery module. SOLUTION: In a solar battery module which has at least a solar battery 12 and a signal generation means 14 for generating a signal by having voltage applied, the solar battery 12 and the signal generation means 14 are connected in parallel. Then, the above voltage is the voltage being outputted by the solar battery 12 connected in parallel with the signal generation means 14 at least.

Analysis and design of a resonant battery charger for photovoltaic systems

Abstract: A solar battery charger using a DC/DC resonant converter with 3 reactive elements operating over a wide load range is presented. This charger is based on a half bridge inverter structure and it can be fed by a solar panels system configured as two current sources, An experimental 100 W/250 kHz unit was built and tested in the laboratory. The operation has been verified with a rechargeable lead-acid battery of 12 V and 1.2 Ah and a HP 6030A DC current source of 200 V and 17 A controlled by a personal computer. The current source follows the characteristic curve of the solar panels.

Performance evaluation of stand-alone wind/photovoltaic generating systems

Abstract: This paper describes the development of a computer model for performance evaluation of stand-alone wind/photovoltaic generating systems. Models for different system components are developed, integrated and used to predict the behavior of generating systems based on available wind/solar and load data. The model is useful for evaluating the performance of stand-alone generating systems and gaining a better insight in the component sizes needed before they are built. Simulation results are presented for performance evaluation of a stand-alone generating system that has been previously designed to supply the average power demand of a typical residential house. An electric water heater model is used as a dump load, and the excess available wind/solar-generated power is used to heat the water. The heated water is used as the inlet water to the main house water heater, which is assumed to be nonelectric.

Study and implementation of the single-phase three-wire photovoltaic energy conversion system

Abstract: A single-stage single-phase three-wire(1/spl phi/3W) photovoltaic energy conversion system connected with a utility power system is presented in this paper. The DC power generated by the solar cells was converted into AC power by a 1/spl phi/3w inverter with an auxiliary LC filter and was fed directly to the utility line. Since the output characteristics of the solar cells were highly affected by the environment and lumen of Sun, the PV energy conversion system was adapted to track the maximum power operation point. The size and weight of the PV conversion system can be largely reduced without energy storage devices, DC to DC converter, and center-tapped transformer. Finally, a 1 kW experimental prototype was built to demonstrate the performance of the proposed technique.

A development of the large capacity telecommunications rectifier system using series-resonant technology and half-bridge topology

Abstract: The development of a 250 kW rectifier system for telecommunication applications using the series-resonant method in a half-bridge topology is detailed in this paper. The proposed system employs an AC distributed power system, which makes it possible to install the power supply close to the switching system, at lower costs and less space, to decrease the power loss in the power feeder system. The proposed system can also use a centralized power system just by extending or exchanging the old equipment. The developed rectifier module uses the resonant control method and a series-resonant technology comprised of two main switches and make a fundamental unit for a small-size and lightweight 100 A module; it has a capacity of 1000 A per rack. The rectifier module adopts a natural air cooling system and an n+1 redundant power system, which improves the reliability since each module is not affected by other broken modules.

Market potential for distributed solar dish-stirling power plants operated in solar-only and solar/natural gas hybrid modes

Abstract: This study was undertaken to estimate utility market potential for dish-Stirling systems (dishes or solar dishes) in the Southwestern United States for the year 2002. Special consideration was given to: 0 Distributed benefits associated with locating generation near loads 0 Value of solar generated electric energy at various times of the daylyear. The study was sponsored by the U.S. Department of Energy (DOE) and managed by the National Renewable Energy Laboratory (NREL). Beyond use as a solar-only conversion device, solar dish-Stirling systems can be hybridized to use nonsolar fuel (e.g., natural gas) to generate: 0 Emergency power at night or on cloudy days 0 When a utility needs more power than insolation can pro-

Device and method for adapting the power of an electric power supply system to actual peak loads

Abstract: The invention relates to a device for adapting the capacity of an electric power supply system (8) to actual peak loads, comprising a power system control center (3)rranged in a supply system (8) and several block-type thermal power stations that are decentralized at consumer level and which can be intermittently turned on and off. The heat from the power stations is transmitted to the consumer along a short route and electric power is fed into the supply system (8). The objective of the invention is to adapt power to meet demand in a precise manner, at short notice and in an economical manner. To achieve this, the system is configured in such a way that the block-type thermal power stations (18) are connected to the distributing center (4) associated with the power system control center (3) by means of data lines (7, 10, 15, 16) and the distributing center (4) associated with the power system control center (3) is provided with a process control system that includes a data acquisition unit for data from the electric power supply system (8) and data from the block-type thermal power stations (18), a data processing unit for data from the electric power supply system (8) and data from the block-type thermal power stations (18) in addition to an output unit for the control signals of the block-type thermal power stations (18).