José Antonio Domínguez Navarro

University of Zaragoza | UNIZAR · Electric Engineering

This work describes a new way to solve the optimal power flow problem applying typed graph neural networks. Typed graph neural networks allow the representation of different elements of transmission systems with different types of nodes, thus adding accuracy and interpretability to the solutions obtained, in comparison to results obtained with conv...

In this paper a novel analytical design methodology for wind power permanent magnet synchronous generators is presented. This kind of electric generator plays a major role in small-scale wind energy conversion systems up to 10 kW. The proposed diameter-cubed sizing equation is based both on the generator requirements, imposed by the application, an...

This paper presents a prototype of a low-cost two-phase axial-gap transverse flux generator, in which the magnetic and electric circuits have been made of reused materials, and the stator housing has been manufactured by 3D printing of plastic. Therefore, this work presents as a novelty the combination of the novel transverse flux topology and two...

In this chapter, the authors briefly describe some of the most popular heuristic techniques, including ant colony optimization algorithm, genetic algorithm, gravitational search algorithm, and particle swarm optimization (PSO), among many others. In addition, the basic implementation of PSO is described and illustrated by solving several optimizati...

This chapter discusses relevant topics related to actual environmental problems, energy commodities, and energy policy. Classification of energy models frequently employed in energy policy development is also discussed. In this context, the optimal power flow and its solution using a real-coded genetic algorithm are carefully explained. Crucial con...

In this chapter, the authors explain basic concepts related to the fundamentals of genetic algorithms. Initially, they discuss the progress of and interest in GAs. Then, they describe the general structure and formulation of a GA, including essential aspects such as coding and fitness calculation for mono-objective optimization (MoOO) and multiobje...

In this chapter, the software tools iHOGA and MHOGA (improved hybrid optimization by genetic algorithms and megawatt hybrid optimization by genetic algorithms) are shown. They are two software tools based on the same architecture: iHOGA is for low- and medium-power systems and MHOGA is used for high-power systems (MW scale). The software uses genet...

This chapter describes significant optimization problems such as economic dispatch (ED), unit commitment (UC), energy arbitrage, and energy system design. The solution of the ED problem using a real-coded genetic algorithm (GA) is explained and presented using four different systems reported in the technical literature. Concerning UC, the priority...

In this chapter, the authors explain a methodology for training a feedforward neural network (FFNN) and a recurrent neural network (RNN) using a genetic algorithm (GA). We use these networks for natural resource estimation. Specific details about the structure and coding of a GA individual are carefully explained, taking advantage of the flexibilit...

In this chapter, basic concepts and techniques related to the prediction of environmental variables such as wind speed and power, solar irradiance, ambient temperature, and electricity price are discussed, including prediction techniques based on time series analysis, artificial intelligence, and more advanced approaches such as numerical weather p...

Transverse flux machines have the potential to offer high torque density in direct-drive vehicle traction applications. Besides, sizing equations are a wide-spread technique for transverse flux machines design, as their computational cost is much lower than the finite element method. In this paper a novel analytical sizing methodology for transvers...

In this paper, a co-simulation of a two-phase axial-gap transverse flux machine is presented. Two pulse-width modulation techniques (hysteresis modulation and sine-triangle modulation) are compared, and different input parameters are varied in order to analyze their influence on the dynamic response of the electric machine. Firstly, the co-simulati...

Wave energy has much more potential and benefits than other forms of renewable energy. It is more predictable, consistent, and controllable than wind or solar energy. In this way, an adequate infrastructure can be an alternative and also sustainable system for power supply. In this paper, different wave energy conversion mechanisms (buoys, Pelamis,...

This document describes the application of multiobjective genetic algorithms as techniques and tools to optimize generation and distribution in small microgrids. In this way, genetic algorithms have been used for the allocation of distributed generation to reduce losses and improve the voltage profile. The IEEE14 network has been taken as a study a...

This paper describes the design of low-cost variablespeed wind turbines by recycling small electrical machines. In this way, electrical machines such as automobile claw-pole alternators, induction motors for domestic applications, or simply electric motors for some industrial applications are studied, considering their reuse as permanent magnet syn...

High torque and power density are unique merits of transverse flux machines (TFMs). TFMs are particularly suitable for use in direct-drive systems, that is, those power systems with no gearbox between the electric machine and the prime mover or load. Variable speed wind turbines and in-wheel traction seem to be great-potential applications for TFMs...

Transverse flux motors (TFMs) are being investigated to be used in vehicle traction applications due to their high torque density. In this paper, a two-phase axial-gap transverse flux motor is designed for an electric scooter, proposing a novel analytical design method. First, the dimensioning equations of the motor are obtained based on the vehicl...

Wind is a physical phenomenon with uncertainties in several temporal scales, in addition, measured wind time series have noise superimposed on them. These time series are the basis for forecasting methods. This paper studied the application of the wavelet transform to three forecasting methods, namely, stochastic, neural network, and fuzzy, and six...

High quality of solar radiation data is essential for solar resource assessment. For remote areas this is a challenge, as often only satellite data with low spatial resolution are available. This paper presents an interpolation method based on topographic data in digital elevation model format to improve the resolution of solar radiation maps. The...

In this work it is shown that artificial neural networks have certain characteristics that make them advantageous in the development of controllers in the different levels of control that microgrids must include to be economic, efficient and able to satisfy the energy power quality and quantity requirements. An objective of this paper is to bring a...

This paper presents the analysis of a hydraulic transmission model used in various types of wave energy conversion systems. In this case, a multi-point absorber wave energy converter is used because its structure is simple and efficient. This design offers some advantages such as greater energy harvesting and stabilization of the output power. In t...

This paper presents an algorithm based on tabu search for locating and sizing FACTS devices in electrical networks. The joint location of the different type of devices improves the performance of the electrical grid. Tabu search uses several indexes to lead the search towards the objective. Solutions obtained show a good voltage profile and values...

This paper presents a decentralized control technique, implemented through a differential power processing topology, in hybrid PEM Fuel Cell systems. This strategy allows the control of the power flow in the cells. The purpose is to improve the maximum power point tracking (MPPT) of the different submodules and thus increase the efficiency of the s...

This paper presents the development and implementation of a control algorithm, based on neural networks, intended for the control and operation of a small robotic prosthesis. The gesture recognition system is based on multiple surface EMG sensors. In this way, it has been possible to control the developed prototype in a simple and effective way. Th...

Flexible AC transmission systems and distributed generation units in power systems provide several benefits such as voltage stability, power loss minimization, thermal limits enhancement, or enables power system management close to the limit operation points; and by extension, economic benefits such as power fuel cost and power loss cost minimizati...

This paper proposes a management strategy for the daily operation of an isolated hybrid energy system (HES) using heuristic techniques. Incorporation of heuristic techniques to the optimal scheduling in day-head basis allows us to consider the complex characteristics of a specific battery energy storage system (BESS) and the associated electronic c...

Fault analysis of modern power systems cannot be only addressed on classical reliability techniques but also considering the impact of cascading failures. This study proposes an original integrated approach for the risk management of a power system subject to random contingencies by using vulnerability and reliability quantitative measures. Five di...

This paper shows, for the first time, the optimisation of the electrical supply in off-grid systems by means of hybrid renewable systems (photovoltaic + wind + battery + fossil fuel) including thermoelectric generator (which source of heat is the exhaust gas of a stove used for cooking or heating). The objective is to minimise the net present cost....

This paper presents a Discontinuous Pulse With Modulation (DPWM) modulation technique applied to a grid-connected three-level neutral point-clamped (3L-NPC) converter. The document proposes a methodology for the control of the active and reactive power flows in a microgrid. The control algorithm of the grid-connected system is applied for voltage c...

Electrical interconnections between countries are needed to improve reliability, security, and stability but increase the risk of a disruption in one country propagating to the neighbouring countries, as has already happened in different power supply interruption events in large regional areas. In this article, we demonstrate that power networks in...

Integration of renewable generation in distribution systems aims to reduce consumption of energy from conventional sources such as coal and oil in order to minimize negative impacts of the human ecological footprint. Massive incorporation of renewables can produce reverse power flow at distribution substations, which is against the operating philos...

In this study, the operation of an energy system composed of a battery energy storage system (BESS) and a conventional generator to compensate the forecasting error of renewable power production has been analyzed. A scenario with low forecasting error and another with high forecasting error have been synthetically modeled and incorporated to a comp...

The main purpose of the REDCRIT research project (http://redcrit.unizar.es/) is the development and validation of a vulnerability assessment methodology for the topology of interdependent energy infrastructures against random faults and intentional attacks. For this purpose, the use of graph theory is proposed by calculating the geodesic vulnerabil...

The evolution of renewable energies and their adoption by the traditional energy system (ES) under the role of distributed generation has driven the interest to management strategies based on distributed algorithms. In this sense, simulation and optimization models able to integrate the intermittent behaviour of wind and solar generation into ES mo...

In recent years, the design of point absorber wave energy converters has been studied with greater attention. Point absorbers are one of the most common wave energy converters. Power electronics and advanced control techniques have allowed the development of new Wave Energy Converters (WECs); in some cases even with the generator coupled to the tur...

This paper proposes a strategy for the active and reactive power flow control, applied to a three-phase power inverter connected to a microgrid. In recent years, smart grids have changed the energy distribution sector. The power quality is essential in the integration of renewable energy sources into small microgrids. These renewable microgrids can...

In this paper, we present a methodology to analyze the integrated operation of coupled natural gas and electricity networks in steady-state. The interaction of the gas network with the electrical grid is modeled through mathematical equations that represent the energy exchange between the two infrastructures. The joint natural gas and power flow is...

This work presents a management strategy for microgrid (MG) operation. Photovoltaic (PV) and wind generators, as well as storage systems and conventional units, are distributed over a wide geographical area, forming a distributed energy system, which is coordinated to face any contingency of the utility company by means of its isolated operation. T...

The development of electric vehicles (EVs) depends on several factors: the EV’s acquisition price, autonomy, the charging process and the charging infrastructure. This paper is focused on the last factor: the design of an EV fast-charging station. In order to improve the profitability of the fast-charging stations and to decrease the high energy de...

The effects of optimal dimensioning and integration of distributed generation (DG) on an electricity distribution system (DS) from a probabilistic viewpoint is presented in this paper, as a new contribution to earlier studies. The proposed methodology pays special attention to preventing reverse power flow at substation as a consequence of excessiv...

The most important single event of the last years in wind energy technology is the reduction in the cost of producing wind electricity offshore, a reduction that can reach 75%, depending on the system boundary considered , for installations commissioned by 2024. Surprisingly, there is very little scientific literature showing how this reduction is...

This document has shown the development and implementation of a control algorithm for the operation of a small bionic hand. As a real-time gesture recognition system, Leap Motion Controller commercial device has been used. The purpose has been to simulate the natural movement of the hand and fingers. Nowadays, technological advances related to robo...

The purpose of this paper has been the construction of a low cost robotic prosthesis and its control through the Arduino platform. The implementation of EMG/ECG electromyographic surface sensors has allowed to develop the control of the robotic arm in a simple and effective way. The system has sought to simulate the natural movements of the arm and...

This paper presents the implementation and validation of a small wind turbine model. The document has studied the feasibility of using small electrical machines (e.g. automotive alternator, induction motors of domestic applications or electrical motors of some industrial application) as low cost generator for small wind turbine; their transformatio...

Wind and solar energy have been taking the control of the renewable energy market, as costs have decreased rapidly and the threats from climate change have made clear the need to change from fossil fuels. Wave energy has been underrated all the past years. Wave energy has more potential and more advantage the other forms of renewable energy. More p...

Switched reluctance machine (SRM) has low cost and good performance in hostile environments and high temperatures. These characteristics made it suitable for applications as electric vehicle. However, its difficult control is a disadvantage for this purpose. In this paper a fuzzy control strategy for switched reluctance machine applied for an integ...

The large-scale integration of photovoltaic generation (PVG) on distribution systems (DSs) preserving their technical constraints related to voltage fluctuations and active power (AP) flow is a challenging problem. Solar resources are accompanied by uncertainty regarding their estimation and intrinsically variable nature. This study presents a new...

Distributed storage systems embedded in distribution power systems could complement renewable generation and improve their operation, reducing peak power levels and providing supply support to island zones in the cases of outages. This paper proposes a multi-objective optimisation, which takes advantage of the possibility of operating in an island...

Dynamic phasors modeling technique has demonstrated to be a good methodology for modeling oscillatory dynamic systems such as electric machines, power electronics and FACTS. Its main advantages are accuracy and fast simulation. However, something that has not been much exploited, is that Fourier coefficients can be used to compute the voltage modul...

The rise of distributed generation makes more difficult the power balance between demand and generation in electrical networks, especially by the uncertainty of renewable generation. Smart grid concepts have been developed to solve this problem. A set of generators, loads and storage devices are locally managed to minimize the energy cost. These sm...

This article presents a method for optimising the daily operation (minimising the total operating cost) of a hybrid photovoltaic-wind-diesel-battery system using model predictive control. The model uses actual weather forecasts of hourly values of wind speed, irradiation, temperature and load. Five control variables are optimised, and thus their op...

Flipped Classroom strategy has achieved significant mention in academic circles in recent years. Flipped Classroom uses in-class time to work on learning materials that were studied and explored by students previously (e.g. presentations, YouTube videos, small concept-test, documents related, etc.). Undoubtedly, the implementation of this education...

Photovoltaic systems, wind turbines and battery storage systems are all commonly present in energy self-sufficiency and independent producers schemes, since they support distributed generation designs. For both cases, single phase inverters provide power conditioning in order to inject micro-sources power to the grid, demanding multiple tasks such...

The application of energy storage in offshore renewable generation systems allows managing the intrinsic uncertainty of the resources and improving the utilization factor of the electrical network. Optimal storage design algorithms generally have to evaluate the behavior of the whole system thousands times before converging to the optimal solution...

Purpose – Renewable generation is a main component of most hybrid generation systems. However, randomness on its generation is a characteristic to be considered due to its direct impact on reliability and performance of these systems. For this reason, renewable generation usually is accompanied with other generation elements to improve their genera...

Advanced PWM charge controllers for lead-acid batteries of PV systems use state of charge (SOC) control and Maximum Power Point Tracking (MPPT). The simulation of the PV system and the effect of the SOC control and MPPT on its performance and on the batteries lifetime is shown.

Nowadays, the great use of small induction motors in domestic applications and other industrial applications justify the development of new servo-drives and motor designs. The main objective should be to improve the efficiency and to consume energy with a clean absorption of current harmonic from the mains. Thereby, this paper presents an applicati...

In the last few years, mobile devices like laptops, tablets and smartphones became more and more popular. Mobile devices have revolutionized the campus because of its low cost and technical capabilities, which together with a widespread of Internet services has caused a change in the behaviour of students. This reality that teachers perceive every...

This paper presents a new technique for the efficiency optimization of an interior permanent magnet synchronous generator, IPMSG, working at variable speed and load. For a given operating condition, characterized by a given turbine speed (ωT) and electric torque (Te), the search control is implemented via the 'Rosenbrock' method, which determines t...

In this paper, the use of the electric vehicle (EV) battery to supply part of the electrical load of the house (when the EV is parked at home) during on-peak hours under time-of-use (TOU) electrical tariff is shown. The EV battery is charged by buying electricity from the AC grid during off-peak hours (at low price), and during on-peak hours (at hi...

The influence of the wind and wave climate on offshore wind operations and maintenance is well known. These environmental factors dictate to a large extent whether turbine crew transfer (carried out by small vessels) or major lifting actions (carried out by large vessels) can be executed at sea. However the role of helicopter operations has receive...

Context: The electric parameters of the power networks are usually analysed through deterministic power flows; however, the variation in load demands and power fluctuation of renewable generators cannot be considered with the deterministic power flows because it uses specific power values. The probabilistic power flow methods are better for this pu...

Wave energy is one of the more promising renewable generation sources. This paper presents a model to optimise the layout of an electrical network that collects the energy generated by a wave farm. The goal is to minimise the cost (installation and losses). With several combinations among AC and DC transmission available, optimization algorithms ea...

In a micro-generation system that includes renewable energies, the reliability assessment might consider the random behavior of the renewable resources. When a planning of this kind of generation systems are carried out, the objectives of interest must be optimized based on outcome of each one, since join them in a single function is not always pos...

Decentralized generation and microgrids are more common in new electric power systems, where each day there is more renewable energy generation from technology such as wind energy conversion systems and photovoltaic systems, connected to the power system through electronic converters and Flexible AC Transmission Systems (FACTS) that are implemented...

The main aim of the present project is to obtain a better understanding of the dynamic control of a wind turbine. To accomplish this, an adaptive dynamic controller was developed and connected to a wind DFIG Simulink model. In order to demonstrate the effectiveness of the controller in question, a three phase fault in the power grid was simulated....

This paper describes an application of the Strength Pareto Evolutionary Algorithm to the multi-objective optimization of a stand-alone PV–wind–diesel system with batteries storage. The objectives to be minimized are the levelized cost of energy (LCOE) and the equivalent carbon dioxide (CO2) life cycle emissions (LCE).Each solution of the Pareto fro...

Decentralized generation and microgrids are becoming more common in electric power systems. Each day, there are more renewable energy technologies such as wind energy conversion systems, photovoltaic (PV) systems, and storage systems with electronic converters that transfer the energy produced by this equipment. Flexible AC Transmission Systems (FA...

A novel method is proposed for designing an energy storage system (ESS) which is dedicated to the reduction of the uncertainty of short-term wind power forecasts up to 48 h. The investigation focuses on the statistical behavior of the forecast error and the state of charge (SOC) of the ESS. This approach gives an insight into the influence of the f...

This paper shows a study of the influence of the type of wind data in the optimization of Wind-Batteries stand-alone systems. We have considered two types of input data for the wind speed: 1) measured wind speed hourly data for a whole year and 2) monthly average wind speed data. When using the second type of data, we generate synthetically the hou...

A high penetration of distributed generation in electricity networks makes it necessary to adapt the network to the new conditions of generation and consumption. Storage units can be converted within a few years in another element of power grids. Therefore, it is necessary to analyze the network to determine the optimal location of distributed gene...

The authors developed a probabilistic method for designing an energy storage system (ESS) which is dedicated to reducing the uncertainty of the short term wind power forecast. Based on the statistical behaviour of the forecast error and the state of charge, ESS capacity is estimated. Energy throughput (equivalent full cycles) and unserved energy ar...

In this paper the methodology for wind speed forecasting with ARMA model is revised. The transformation, standardization, estimation and diagnostic checking processes are analyzed and a discrete probability transformation is introduced. Using time series historical data of three weather stations of the Royal Netherlands Meteorological Institute, th...

This paper presents, for the first time, an application of a Multi-Layer methodology to solve the Multi-Period and Multi-Objective design of power distribution systems. The methodology consists of two steps. In the first, an improved version of the Strength Pareto Evolutionary Algorithm (SPEA) is applied to the Multi-Objective design of Power Distr...

In this paper, a novel methodology to price the reactive power support ancillary service of Distributed Generators (DGs) with primary energy source uncertainty is shown. The proposed methodology provides the service pricing based on the Loss of Opportunity Costs (LOC) calculation. An algorithm is proposed to reduce the uncertainty present in these...

A novel method is proposed for designing an energy storage system (ESS) which is dedicated to reducing the uncertainty of the short term wind power forecast. The investigation focuses on the statistical behaviour of the forecast error and the state of charge (SOC) of the ESS. This approach gives an insight into the influence of the forecast conditi...

This paper presents a new method in data mining to analyze the composition of the electric demand among the different consumption and the behavior of each type of load. The proposed method uses a heuristic optimization algorithm (Tabu Search) for minimizing the error between the real demand and the calculated approximation to this demand. This sear...

This paper describes a simple and economical way to improve the behaviour of a stall control wind turbine with fixed speed induction generator during faults. It proposes using the existing thyristor bridge and capacitors in combination with new resistors, to create a self-exciting system isolated from the grid during faults, controlling the termina...

This paper presents an hourly management method for energy generated in grid-connected wind farms using battery storage (Wind-Batteries systems). The method proposed is analysed technically and economically. Electricity generation in wind farms does not usually coincide with the electrical demand curve. If the wind-power penetration becomes high in...

This note presents a new technique for efficiency optimization of induction generators working at variable speed and load. The technique combines two distinct control methods, namely, on-line search of the optimal operating point and a model based efficiency control. For a given operating condition, characterized by a given turbine speed (ωT) and e...

Power systems stability has been analysed specially due to the quick increasing of wind power penetration all around the world, specific in USA and Europe. This research presents the small signal stability analysis based on Kundurpsilas theory but specifically for wind turbines with squirrel cage induction generators - SCIG, understood as a widely...

Wind power forecast error usually has been assumed to have a near Gaussian distribution. With a simple statistical analysis, it can be shown that this is not valid. To obtain a more appropriate probability density function (pdf) of the wind power forecast error, an indirect algorithm based on the Beta pdf is proposed. Measured one-year time series...

This paper shows the optimization of a PV- Wind system to supply the demand of water pumping in a small town in Bolivia. This work has been done with the HOGA program (Hybrid Optimization by Genetic Algorithms). The objective function to minimize in the design process is the total Net Present Cost (NPC) of the system. The system is defined as a com...