| EPE 1997 – 41: Dialogue Session DS8g: RENEWABLE ENERGY | ||
| You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 41: Dialogue Session DS8g: RENEWABLE ENERGY | ||
 | [return to parent folder] | |
 | GLOBAL CONTROL FOR TWO PHOTOVOLTAIC APPLICATIONS: PUMPING AND CONNECTING TO THE GRID SYSTEMS
By J. A. Dominguez; S. Lorenzo; S. de Pablo; S. Caceres | |
|
Abstract: Generally, photovoltaic (PV) systems have two independents controls:
I.- DC control for the DC/DC converter to track the Maximum Power Point of the PV array.
2.- AC control for the DC/AC converter to feed, efficiently, the load attached to it.
This paper shows how to design a Global Control, using Field Orientation, avoiding to use the DC/DC converter, and fmding the relationships among the DC magnitudes and AC ones. So,
only the inverter is necessary to control the PV array and the AC load. Two cases are
considered: pumping with an asynchronous machine and connecting to the grid systems. One 10kW prototype has been built to validate the theory. It has been tested in laboratory successfully.
| ||
| | HYBRID PHOTOVOLTAIC POWER SYSTEM USING A PARAMETRIC INDUCTION GENERATOR
By Y. Sakamoto; M. Natsusaka; K. Murakami | |
|
Abstract: The paper describes a new hybrid photovoltaic power system using a
parametric induction generator, which can effectively utilize alternative
energies such as wind and solar power. The system is a separately or a selfexcited
parametric induction generator system. The basic operations of the
generator, including the harmonic currents and the power factor, are investigated
to determine the practical usability of the system. The possibility of analysis
of the generator using the equivalent circuit is also made clear.
| ||
| | POWER CONDITIONING OF LOW VOLTAGE GENERA TORS WITH TRANSFORMERLESS GRIDCONNECTED INVERTER TOPOLOGIES
By J. M. A. Myrzik | |
|
Abstract: In the last few years the development of small inverters in photovoltaic (PV) and battery technology was
supported by creating modular systems. However, the specific costs of small inverters are still too high. The high
costs result among other things of the passive components, especially from the SO Hz transformer. Two new inverter
topologies without a transformer are being presented which allows the connection of a low voltage generator to the
utility grid. A derivation scheme, design and experimental results from test circuits are being discussed.
| ||
| | STUDY OF A VARIABLE RELUCTANCE GENERATOR FOR WIND POWER CONVERSION
By I. Haouara; A. Tounzi; F. Piriou | |
|
Abstract: The aim of this communication is to study a doubly slotted reluctance generator for
direct driven wind energy conversion. This structure is known for its operating at high torque
and low speed but its power factor is generally very poor. To get over this disadvantage, we
propose a structure which is excited by permanent magnets inserted in the rotor.
In a first part, we present the proposed machine and the calculations which allow to determine
the geometric parameters and the windings polarities for a given speed. The determination of
magnetic parameters is achieved using an analytical approach and Finite Element Method
(FEM).
In a second part, we calculate the inductances by both analytical and FEM approaches and
achieve a three phase modelling.
To complete our study, the simulation of the machine, loaded by resistances, is performed by
FEM .and using the three phase modelling. Results are given and discussed.
| ||
| | WIND-POWERED PUMPING SYSTEM USING INDUCTION MACHINES WITH PULSE WIDTH MODULATION (PWM) EXCITATION
By M.S. Miranda; R.O.C. Lyra; S.R. Silva | |
|
Abstract: An isolated small wind electric pumping system (SWEPS) comprising induction machines is
proposed. A pulse width modulation (PWM) converter is used to provide the reactive power demanded
by the machines through an indirect vector control strategy. The generator is driven by a wind turbine
and feeds a pumping unit in variable frequency. The system operates at variable speed and motor
overloading is avoided by turbine pitch control action. Simulation and experimental results are presented
and analyzed.
| ||
| | A TEST-RIG TO EVALUTATE A WIND TURBINE GENERATION CONTROL SYSTEM BASED ON DSP
By F. Barrero; J. L. Mora; M. Perales; A. Marchante; E. Galvan; J. M. Carrasco; A.Torralba; L. G. Franquelo | |
|
Abstract: The purpose of this paper is to describe a test-rig used to evaluate some control policies
for wind-energy conversion systems. A current controlled DC motor is used to implement
a model of Variable Speed and Pitch-angle Wind Turbine. This DC motor drives an induction
generator. Two inverters are used to control the power delivered from the induction generator.
The first inverter implement a variable speed vector control of the induction generator and the
second one handle the power injected into the utility grid. At this moment, this system is under
experimentation and some experimental results are shown in this paper.
| ||
| | MODELLING AND SIMULATION OF AN AUTONOMOUS WIND/DIESEL SYSTEM EQUIPPED WITH FORCED COMMUTATED CONVERTER
By M. l. Palsson; K Uhlen, T. Toftevaag | |
|
Abstract: Power quality is a field of growing interest; among other because in recent years power electronic
components of increasing capacity have been introduced in power systems. Use of power electronic components is of
current interest in wind/diesel systems. In such systems a converter can be used in combination with a battery storage
bank to compensate for the power fluctuations due to the stochastic nature of the wind. The power quality aspect in
such systems should be treated with the same care as in power systems in general. In this paper we propose a model of a wind/diesel system, including wind turbine with a generator, diesel generator
set, forced commutated converter and consumer load. This model is used for simulation studies, with emphasis on
transient analysis and dynamic control. The models of the converter and its controls are of main concern here.
Therefore this paper focuses mainly on these models and their usage in order to enhance the power quality in
wind/diesel systems.
| ||
| | MODELLING AND EXPERIMENTAL INVESTIGATION OF ENERGY CONVERSION SYSTEMS EMPLOYING WIND-DRIVEN INDUCTION GENERATORS WITH ELECTRONICALLY CONTROLLED ...
By F. Castelli Dezza; A. Di Gerlando; R. Perini | |
|
Abstract: Some conversion systems from wind into electric energy, for feeding remote loads, employ induction generators
excited by means of capacitor benches. In this paper, a system solution is analysed, in which the regulation of the reactive
power, necessary for the generator, is operated in a continuous mode by means of a Static V AR Control; the energy is
delivered to a storage battery and to a load via a diode rectifier and a chopper, that regulates the absorbed power in such a
way to maintain the turbine in optimal operating conditions. Both the design criteria of the system components and the
theoretical results of the steady state operation analysis are described. These results, as like as those obtained by the time
domain numerical simulation, are thus compared with those obtained by ell."jlerimental tests performed in laboratory.
| ||
| | POWER ELECTRONIC INTERFACE FOR UNCONVENTIONAL SMALL SIZE STAND ALONE WIND ENERGY CONVERSION SYSTEM
By G. Lo Bianco; F. Caricdri; F. Crescimbini; L. Solero | |
|
Abstract: This paper presents a d.c.-to-d.c. converter conceived for small-size stand alone wind energy
conversion systems devoted to battery charging. An electronic power converter interface improves the performance
of the whole system which operates at variable speed. This paper highlights the unconventional features of the
proposed power electronic interface and discusses a control method for maximising the system power output.
Design and construction of 2kW power conditioner prototype were carried out at the University of Rome, and a
long-term monitoring campaign of the system running operation is being carried out to evaluate the prototype
performance. Experimental results taken from a laboratory test campaign are reported.
| ||