Manuel Ortega

Neuro-fuzzy controller for gas turbine in biomass-based electric power plant

Abstract Biomass gasification is a technology that transforms solid biomass into syngas. The gas turbine controller regulates both the gas turbine and the gas turbine generator. Two fuzzy logic controllers have been developed using speed and mechanical power deviations, and a neural network has been designed to tune the gains of the fuzzy logic controllers based on the operating conditions of the biomass-based electric power plant. It is shown that by tuning the fuzzy logic controllers, optimal time domain performance of the system can be achieved in a wide range of operating conditions compared to fixed parameter fuzzy logic controllers and PID controllers.

Model Based Predictive Control of Fuel Cells

The solid oxide fuel cell power plant is known to be a potential alternative in the electric utility field. However, the output voltage of the solid oxide fuel cell changes with load variations. Model predictive control is part of a family of optimization based control methods, which are based on on-line optimization of future control moves. This paper proposes a model based controller for the regulation of a solid oxide fuel cell. Performances using both linear and fuzzy Hammerstein models are evaluated with constraints.

New topology for DC/DC bidirectional converter for hybrid systems in renewable energy

This article presents a new isolated DC/DC bidirectional converter with soft switching, using a transformer with two voltage taps and two full bridges with insulated-gate bipolar transistors (IGBTs), one on each side of the transformer to be integrated in hybrid systems of renewable energy. A large voltage conversion ratio can be achieved using this converter, in buck and booster modes. Also medium and high DC power can be converted with a good efficiency. Analysis and switching techniques have been reported. To verify the principle of operation, a laboratory prototype of 10 kW has been performed. Experimental results are presented, operating in boost mode. The switching algorithm used has been modelled in MATLAB-Simulink to generate C code. This code has been implemented in a DSP F2812, which has been used to build the prototype.

Predictive Control of Matrix Converter-based Micro-turbine

Abstract This paper suggests a model-based controller for the regulation of a micro-turbine. The performance using the linear model is studied with constraints. The matrix converter is an array of controlled semiconductor switches that directly connects the three-phase source to the three-phase load. This article investigates the use of a matrix to interface a high-speed micro-turbine generator (MTG) to a utility grid as a distributed generation unit. A predictive control for the micro-turbine is presented. Based on time-domain simulations in MATLAB, the dynamic behavior of a micro-turbine and predictive control are studied. The work concludes that a matrix converter is technically a viable option to interface a MTG to a utility grid.

Bidirectional output stage matrix converter applied to a distributed generation system

In this article a new bidirectional output stage ultra-sparse matrix converter (BOSUMC) is presented. This converter is designed for connecting a hybrid electrical system to a distributed generation network. The proposed converter comprises an input stage and an output stage with six bidirectional switches in such a way that both the input and output stages are linked with a DC link, which can be coupled to an electrolyser and a fuel cell. The converter allows the current to flow in both ways in its output stage, and if there is an excess of energy in the network, it can be transformed into electric direct current and later into hydrogen for its exploitation. For verifying the control algorithm of the BOSUMC, a laboratory prototype has been prepared using among other elements a Spectrum Digital eZdsp™ TMS320F2812 card.

Analysis and simulation of a six-phase matrix converter

Matrix converters are becoming an actual alternative for many AC–AC power conversion applications. This paper shows that it is possible to use the six‐phase matrix converter to increase the maximum voltage gain. A complete diagram of simulation is presented. At last, evaluation of the study over students is showed.

Fuzzy Hammerstein model based predictive control of a solid oxide fuel cell

The solid oxide fuel cell power plant is known to be a potential alternative in the electric utility. However, the output voltage of the solid oxide fuel cell changes with the load variations. Model predictive control is part of a family of optimization-based control methods, which are based on online optimization of future control moves. This paper proposes a model-based controller for the regulation of a solid oxide fuel cell. The performances using both the linear and fuzzy Hammerstein models are evaluated with constraints

Enhancing the electrical performance of a micro-turbine using a genetic fuzzy controller

The connection between the micro-turbine and the load is through in inverter using pulse width modulation. This paper explains the application of genetic algorithms for current harmonic reduction in a DC/AC inverter. Harmonic reduction is redrafted as an optimization problem and steps of the genetic algorithms are applied. Compared to conventional optimization techniques, the steps of the genetic algorithms are very simple and global optimum is guaranteed in most cases. The simulation results clearly demonstrate the efficacy of the genetic algorithms in harmonic reduction.

Analysis of a six-phase matrix converter in microturbine based distributed generation systems

The authors contrast two topologies for direct AC-AC matrix converters: namely, a conventional three-phase matrix converter and a novel six-phase matrix converter. Comparison of the relative performances is made with regard to voltage and current harmonics, and impact of dead time in the firing pulses on harmonic distortion. A performance study of each topology feeding a passive load is carried out and performance results are obtained. The work is accomplished by means of the Matlabtrade software.

Improvement of output voltage using six-phase matrix converter

Six-phase matrix converters allow an all-silicon solution to the problem of changing AC power from one frequency to another. A simple model is purposed to simulate the power circuit, as well as the filters. The power semiconductors are modeled as ideal bidirectional switches and the matrix converter is controlled using a direct transfer function approach. This paper shows that it is possible to use the six-phase matrix converter to increase the maximum voltage gain.