Showing papers on "Power optimizer published in 1982"

Wind turbine maximum power tracking device

Abstract: A method and apparatus for controlling the level of power transferred through a stand-alone wind power generating system utilizing a wind turbine whose output is converted to electrical power by means of an induction generator are disclosed. In the disclosed system, the velocity of the wind incident upon the blade of the turbine is sensed by a velocity sensor. This information is then used to vary the excitation frequency applied to the generator to adjust the shaft speed of the turbine in proportion to the change in wind velocity. The excitation frequency is adjusted in accordance with a control algorithm so that the power output of the system is equal to a maximum fraction of available wind power at wind velocities below a pre-determined power/velocity point.

Control Design of an Active and Reactive Power HVDC Modulation System with Kalman Filtering

Abstract: This paper discusses results of an EPRI contract on control design for an ac/dc transmission system to increase power transfers limited by dynamic stability. The control is acbieved by modulating the rectifier dc current or power and the inverter dc voltage. Coordinated active and reactive power modulation is accomplished by Linear Quadratic (LQ) control design. Improved performance is realized by utilizing reactive power coupling between dc and ac networks to modulate dc and ac active power. For the demonstration system, power modulation with coordinated voltage modulation is shown to be about ten times more effective than power modulation alone. Control interactions between electromechanical modes of oscillation are eliminated by Kalman filtering. Filtering permits excellent control performance with a minimum of system measurements. Modern control technology is applied within realistic system constraints, such as measurements.

New solar cell power supply system using a boost type bidirectional DC-DC converter

Abstract: New solar cell power supply system is presented, in which the boost type bidirectional dc-dc converter and the simple control circuit with a small monitor solar cell are employed to track the maximum power point of the solar array. It is confirmed by the experiment that the new system has the sufficiently precise tracking operation performance and the satisfactorily high power efficiency. Also, a comparison of the power efficiencies is made with theoretically as well as experimentally on the new and the conventional solar cell power supply systems. As a result, it is revealed that the new system is superior to the conventional one in the power efficiency.

Maximum power point tracker for photovoltaic power plants

Abstract: The paper describes two different closed-loop control criteria for the maximum power point tracking of the voltage-current characteristic of a photovoltaic generator. The two criteria are discussed and compared, inter alia, with regard to the setting-up problems that they pose. Although a detailed analysis is not embarked upon, the paper also provides some quantitative information on the energy advantages obtained by using electronic maximum power point tracking systems, as compared with the situation in which the point of operation of the photovoltaic generator is not controlled at all. Lastly, the paper presents two high efficiency MPPT converters for experimental photovoltaic plants of the stand-alone and the grid-interconnected type.

A Low Distortion PWM DC-AC Inverter, with Active Current and Voltage Control, Allowing Line-Interfaced and Stand-Alone Photovoltaic Applications

Abstract: The energy transfer between a photovoltaic solar panel and the grid can be realized by means of a DC-AC inverter, which is described in this paper. A reliability study of the entire system (i.e. the solar panels and the inverter) shows that the voltage generated by the solar panel matrix has to be low (≪ 100 V). The stability conditions of the energy transfer dictate a current source behaviour of the inverter. This is realized by means of an appropriate feedback system. In this way a voltage inverter type can be used instead of the current inverters which are usually proposed, so the relatively heavy and expensive inductors can be omitted. This also allows the inverter to be used as an AC voltage power supply, in the absence of the power grid.

Characteristics of a small wind-power system with dc generator

Abstract: The performance characteristics of a small-scale wind-power system with a separately or self-excited DC generator are analysed and experimentally confirmed. The relations between output and wind speed are derived, and their effect on performance is discussed.

Study on simulations and elementary characteristics of a windmill generator system

Abstract: The world energy problem has stimdlated interest in the application of wind power. The attempts have been made to develop wind power systems as auxiliary supplies for local energy.The main motivation for this study is to clarify the performance of a wind power system. In this paper, the performance has been analyzed by means of analog simulation.From the results of the simulation, it is seen that the characteristics are affected considerably nature of wind and each parameter of a wind power system.

Microprogrammed Coupling System for Photovoltaic Generators with Multiple Receptors

Abstract: When photovoltaic generators have a power greater than a few kilowatts, they are often coupled to multiple receptors of diverse characteristics In such cases it is necessary to optimise their operation and arrange for the proper allocation of energy among them