Modeling and Analysis of Power Processing Systems (MAPPS), initial phase 2

The overall objective of the program is to provide the engineering tools to reduce the analysis, design, and development effort, and thus the cost, in achieving the required performances for switching regulators and dc-dc converter systems. The program was both tutorial and application oriented. Various analytical methods were described in detail and supplemented with examples, and those with standardization appeals were reduced into computer-based subprograms. Major program efforts included those concerning small and large signal control-dependent performance analysis and simulation, control circuit design, power circuit design and optimization, system configuration study, and system performance simulation. Techniques including discrete time domain, conventional frequency domain, Lagrange multiplier, nonlinear programming, and control design synthesis were employed in these efforts. To enhance interactive conversation between the modeling and analysis subprograms and the user, a working prototype of the Data Management Program was also developed to facilitate expansion as future subprogram capabilities increase

A maximum power point tracking scheme for a 1kw stand-alone solar energy based power supply

This paper elucidates one of the tracking schemes for a photovoltaic (PV) systems using Cuk converter operating in discontinuous inductor current mode (DICM) as an interface. A method for efficiently maximizing the output power of a solar panel supplying a load or battery bus under varying meteorological conditions is investigated and results presented therein. The incremental conductance (InCond) method of maximum power point tracking (MPPT) using the Cuks dc to dc converter operating in a discontinuous inductor current mode (DICM) was modeled and studied in relation to PV system interface. Also, laboratory setup was implemented based on the model. This was the main objective of the research. Similarly, the PV simulator was also modeled alongside with Cuk converter operating in DICM. MATLAB/SIMULINK software was used to carry out simulation test. With the incremental conductance method, the problem of sustained oscillation around the maximum power point of the solar panel which is the usual characteristic of the perturbation and observation method is essentially absent. The result disclosed that the power available for the load when MPPT was applied was 1.1 kW which gives a tolerance of 0.1% to the load it powers. But without MPPT, the available power is 0.9 kW using the same number of PV panels and batteries as back up. Hence, MPPT has 17.65% edge in power delivery over non-MPPT PV powered energy supply. An experimental prototype of a 1kW, 230V, 50Hz stand-alone solar based power supply with the incremental conductance scheme was successfully implemented using PIC 16F877 microcontroller, tested and results presented therein. The experimental results agreed with the simulated results.Keywords: Maximum Power point tracking, Cuk converter, Photovoltaic system, PIC 16F877A micro-controller, inverter, batteries

Fuzzy logic controller for half car active suspension system

This work presents the MATLAB/Simulink simulation results of half car active suspension system controlled by the fuzzy logic controller. The half car model consists of one front and rear wheel. Firstly, a mathematical model of the suspension system is developed. Based on the developed mathematical model, the fuzzy logic controller for the system is designed. The input to the controller is the vertical displacement and velocity of the front body of the vehicle. The membership function of these two variables is adjusted accordingly so that the output, i.e., the car body acceleration, the deflection of the wheels and other output are better than that of the passive suspension system. The results clearly show that all of the active suspension system output has improved when compared to that of the passive system

Control Strategies of DC–DC Converter in Fuel Cell Electric Vehicle

There is a significant need to research and develop a compatible controller for the DC–DC converter used in fuel cells electric vehicles (EVs). Research has shown that fuel cells (FC) EVs have the potential of providing a far more promising performance in comparison to conventional combustion engine vehicles. This study aims to present a universal sliding mode control (SMC) technique to control the DC bus voltage under varying load conditions. Additionally, this research will utilize improved DC–DC converter topologies to boost the output voltage of the FCs. A DC–DC converter with a properly incorporated control scheme can be utilized to regulate the DC bus voltage–. A conventional linear controller, like a PID controller, is not suitable to be used as a controller to regulate the output voltage in the proposed application. This is due to the nonlinearity of the converter. Furthermore, this thesis will explore the use of a secondary power source which will be utilized during the start–up and transient condition of the FCEV. However, in this instance, a simple boost converter can be used as a reference to step–up the fuel cell output voltage. In terms of application, an FCEV requires stepping –up of the voltage through the use of a high power DC–DC converter or chopper. A control scheme must be developed to adjust the DC bus or load voltage to meet the vehicle requirements as well as to improve the overall efficiency of the FCEV. A simple SMC structure can be utilized to handle these issues and stabilize the output voltage of the DC–DC converter to maintain and establish a constant DC–link voltage during the load variations. To address the aforementioned issues, this thesis presents a sliding mode control technique to control the DC bus voltage under varying load conditions using improved DC–DC converter topologies to boost and stabilize the output voltage of the FCs

Modeling and control of stand-alone AC microgrids: centralized and distributed storage, energy management and distributed photovoltaic and wind generation

El aumento de la penetración de energías renovables en la red eléctrica es necesario para el desarrollo de un sistema sostenible. Para hacerlo posible técnicamente, se ha planteado el uso de microrredes, definidas como una combinación de cargas, generadores distribuidos y elementos de almacenamiento controlados gracias a una estrategia global de gestión energética. Además, las microrredes aumentan la fiabilidad del sistema puesto que pueden funcionar en modo aislado en caso de fallo de red. Esta tesis se centra en el desarrollo de microrredes AC en funcionamiento aislado. El objetivo principal es el diseño y la implementación de estrategias de gestión energéticas sin utilizar cables de comunicación entre los distintos elementos, lo que permite reducir los costes del sistema y aumentar su fiabilidad. Para ello, se abordan los siguientes aspectos: • Gestión energética de una microrred AC con generador diesel, almacenamiento centralizado y generación renovable distribuida • Diseño de técnicas de control “droop” para repartir la corriente entre inversores conectados en paralelo • Gestión energética de una microrred AC con almacenamiento distribuido y generación renovable distribuida • Control de la etapa DC/DC de inversores fotovoltaicos con pequeño condensador de entrada en el seno de una microrred • Control de extracción de máxima potencia sin sensores mecánicos para sistemas minieólicos en el seno de una microrred.The introduction of distributed renewable generators into the electrical grid is required for a sustainable system. In order to increase the penetration of renewable energies, microgrids are usually proposed as one of the most promising technologies. A microgrid is a combination of loads, distributed generators and storage elements which behaves as a single controllable unit for the grid operator. Furthermore, microgrids make it possible to improve the system reliability because they are capable of standalone operation in case of grid failure. This thesis is focused on the development of AC microgrids under stand-alone operation. Its main objective is to design and implement overall control strategies which do not require the use of communication cables, thereby reducing costs and improving reliability. For this purpose, the following aspects are tackled: • Energy management of an AC microgrid with diesel generator, centralized storage and distributed renewable generation • Design of droop methods so that the current is shared among parallel-connected inverters • Energy management of an AC microgrid with distributed storage and distributed renewable generation • Control of the DC/DC stage in photovoltaic inverters with small input capacitors within a microgrid • Sensorless MPPT control for small wind turbines within a microgrid.Programa Oficial de Doctorado en Energías Renovables (RD 1393/2007)Energia Berriztagarrietako Doktoretza Programa Ofiziala (ED 1393/2007

Multiple-output DC–DC converters: applications and solutions

Multiple-output DC–DC converters are essential in a multitude of applications where different DC output voltages are required. The interest and importance of this type of multiport configuration is also reflected in that many electronics manufacturers currently develop integrated solutions. Traditionally, the different output voltages required are obtained by means of a transformer with several windings, which are in addition to providing electrical isolation. However, the current trend in the development of multiple-output DC–DC converters follows general aspects, such as low losses, high-power density, and high efficiency, as well as the development of new architectures and control strategies. Certainly, simple structures with a reduced number of components and power switches will be one of the new trends, especially to reduce the size. In this sense, the incorporation of devices with a Wide Band Gap (WBG), particularly Gallium Nitride (GaN) and Silicon Carbide (SiC), will establish future trends, advantages, and disadvantages in the development and applications of multiple-output DC–DC converters. In this paper, we present a review of the most important topics related to multiple-output DC–DC converters based on their main topologies and configurations, applications, solutions, and trends. A wide variety of configurations and topologies of multiple-output DC–DC converters are shown (more than 30), isolated and non-isolated, single and multiple switches, and based on soft and hard switching techniques, which are used in many different applications and solutions.info:eu-repo/semantics/publishedVersio

Single-Stage Power Electronic Converters with Combined Voltage Step-Up/Step-Down Capability

Power electronic converters are typically either step-down converters that take an input voltage and produce an output voltage of low amplitude or step-up converters that take an input voltage and produce an output voltage of higher amplitude. There are, however, applications where a converter that can step-up voltage or step-down voltage can be very useful, such as in applications where a converter needs to operate under a wide range of input and output voltage conditions such as a grid-connected solar inverter. Such converters, however, are not as common as converters that can only step down or step up voltage because most applications require converters that need to only step down voltage or only step up voltage and such converters have better performance within a limited voltage range than do converters that are designed for very wide voltage ranges. Nonetheless, there are applications where converters with step-down and step-up capability can be used advantageously. The main objectives of this thesis are to propose new power electronic converters that can step up voltage and step down voltage and to investigate their characteristics. This will be done for two specific converter types: AC/DC single-stage converters and DC-AC inverters. In this thesis, two new AC/DC single-stage converters and a new three-phase converter are proposed and their operation and steady-state characteristics are examined in detail. The feasibility of each new converter is confirmed with results obtained from an experimental prototype and the feasibility of a control method for the inverter is confirmed with simulation work using commercially available software such as MATLAB and PSIM

Survey on Photo-Voltaic Powered Interleaved Converter System

Renewable energy is the best solution to meet the growing demand for energy in the country. The solar energy is considered as the most promising energy by the researchers due to its abundant availability, eco-friendly nature, long lasting nature, wide range of application and above all it is a maintenance free system. The energy absorbed by the earth can satisfy 15000 times of today’s total energy demand and its hundred times more than that our conventional energy like coal and other fossil fuels. Though, there are overwhelming advantages in solar energy, It has few drawbacks as well such as its low conversion ratio, inconsistent supply of energy due to variation in the sun light, less efficiency due to ripples in the converter, time dependent and, above all, high capitation cost. These aforementioned flaws have been addressed by the researchers in order to extract maximum energy and attain hundred percentage benefits of this heavenly resource. So, this chapter presents a comprehensive investigation based on photo voltaic (PV) system requirements with the following constraints such as system efficiency, system gain, dynamic response, switching losses are investigated. The overview exhibits and identifies the requirements of a best PV power generation system