Jorge Marcos

Grid-synchronization methods for power converters

Grid synchronization is an important part in the control of grid-connected power electronic converters. The fundamental phase-angle at the point of common coupling should be tracked on-line in order to control energy transfers. Digital implementation allows to implement high performance algorithms, which are robust in the presence of power quality phenomena. However, different kinds of distortion cause a reduction of the effective bandwidth, and hence, affects to the transient response of the equipment. This paper reviews some of the highest performance algorithms for grid synchronization: phase locked loops (PLL), schemes based on synchronous reference frames (SRF) and digital filtering and finally, stochastic filtering based methods. The pros and cons of each one are assessed and some interesting techniques to enhance the dynamics are provided. The assessment in the presence of frequency deviations is analyzed in detail. The most significant techniques to provide a better frequency adaptation are enumerated and analyzed in the last section of this paper.

FPGA implementation of a fuzzy controller for automobile DC-DC converters

The design of synchronous multiphase DC-DC converters for automobile applications is now a very active field, because the automotive industry forecast that future power demands inside a car will oscillate between 2.5 kW and 3.5kW, keeping a dual system of 42/14V batteries. The design of controllers for the optimal behavior of such converters is a very delicate task. In this paper, an optimized fuzzy control algorithm has been developed to control a synchronous multiphase converter of 1.6kW. First, the fuzzy control algorithm is designed and verified, together with a non linear model of the converter power stage, by means of Matlab and Simulink. Then, the fuzzy controller hardware is developed through Xilinx System Generator for Simulink, and implemented in a Spartan 3 FPGA to achieve a real-time controller

Geometric Analysis and Manufacturing Considerations for Optimizing the Characteristics of a Twisted Pair

The geometry of a twisted pair largely determines its electrical characteristics. To improve and refine the value of these characteristics according to preset values, the optimization of the manufacturing processes requires comprehensive knowledge of twisted pair geometry and of how electrical magnitudes are affected by the construction features of the twisted pair. This paper studies the relation between the length of a twisted pair cable and the length of each of the wires that compose the cable, by analyzing concepts such as pitch angle and radius of the helix. In addition, it examines the deformations and irregularities that can occur in the twisted pair during the manufacturing process and their effects on the geometry of the twisted pair. Results showed in this paper are a part of a larger research project carried out in association with the R&D department of a cable manufacturing company, and these results are being applied into the design department of this company.

An approach to real behaviour modeling for traction lead-acid batteries

At the present time, the batteries are the main obstacle in the race toward the total development of the electric vehicles. In this article we present a PSPICE model for lead-acid batteries of traction that represents an approach of the real behavior of these so that it can be analyzed directly from the PSPICE environment. This model is flexible and can be adjusted in function of the type of electrochemical battery.

Safe PLD-based programmable controllers

In many industrial processes, an incorrect operation can lead to irreparable damage to people, equipment, or the environment. In order to reduce risks, the electronic control systems used in this kind of processes must comply with international standard safety requirements. The safety market solutions are mainly based in the use of high-end programmable logic controllers (PLCs) and/or application specific integrated circuits (ASICs) for concrete processes or machines. The solutions proposed in this paper are based on the implementation of safety redundant control systems in programmable logic devices (PLDs and FPGAs). The proposed methodology for safe controllers design is based on the combination of dynamic logic and redundant circuits with voting capabilities. The use of programmable logic devices (PLDs) instead of high-end programmable logic controllers (PLCs) adds flexibility to the design of safety-related control systems and reduces costs, while maintaining high reliability and a good degree of failure detection.

High voltage power supply for rotary die laser cutting system

A rotary die laser cutting system (RDLCS) processes several types of material; materials include all kind of plastics, thin films, papers, plywood, cardboard and thin metals. Applications include engraving, marking names, logos, designs, and patterns. Our RDLCS contains eighteen CO/sub 2/ laser tubes, the number of tubes used in each application can vary depending on the type of material and the application. Each laser tube is fed by a 350 W power supply, the ON/OFF state of the power supply and laser tube are controlled by a computer and a programmable logic controller (PLC). This paper describes the design and implementation of the power supply for each of the CO/sub 2/ laser tubes used in the RDLCS. The power supply must be able to supply to the CO/sub 2/ laser tube a voltage of 8 kV and a current of 30 mA. The power supply was designed for ensuring the compliance with the EN 61000-3-2, and contains a single phase passive power-factor-corrected rectifier, a half-bridge inverter and a high-voltage multiplier.

Remote System of Design and Test of DC-DC Converters

The increasing interest in remote test and experimentation has allowed the incorporation to the educative system of new tools that improve the classic methods of education. In the field of the Power Electronics, the possibility of access of the engineering student through the development of this type of tools to equipment generally of high cost, and therefore of low availability in the educational laboratories, is very important. This work shows a Remote System of Design and Test of DC/DC Converters (RSDTC) that can be used either locally or remotely. The developed system is based on a test bench manufactured by Hewlett-Packard. Taking as its starting point this equipment, a software application has been developed using the visual programming language “LabVIEW”. This programming tool combined with CGI (Common Gateway Interface), allows the developed analysis system to be executed remotely using a web browser.

Considerations of DSP controlled VSC based STATCOM

The paper presents the analysis of the PWM static VAr compensator (STATCOM) when the pole assignment control method is used in order to improve the dynamic response. The STATCOM is based on a conventional six-switch bi-directional voltage source converter topology using insulated gate bipolar transistors (IGBTs). The sinusoidal pulse width modulation technique is used to control the converter output voltage (amplitude and phase). Two references DC voltage for DC voltage control are using and the trade-off between the value of the DC capacitor and the ripple voltage and the systems transient response time are investigated. The control system, has incorporated VAr calculator and synchronization, which, together the control algorithm, has been implemented on a digital signal processing (DSP) board, to achieve excellent overall performance. Experimental results for both leading and lagging VAr compensation, along with changes between them, confirm the good performance and the flexibility of the developed prototype.

An Optimal New Shielded Twisted Pair Model to Improve the Electromagnetic Immunity in the Automotive Applications

Shielding twisted pair with metallic tape is a widely used resource to reduce the electromagnetic emissions and increase noise immunity of the twisted pair to those emissions. But, in addition to decrease electromagnetic emissions, shield also affects electric and geometry characteristics of the pair. Estimation of twisted pair geometry is vital to compute as much as the shield affects the electric characteristics of the pair. The goal of this paper is to develop a model of shielded twisted pair which allows to compute the shield shape as a function of twisted properties of the pair and physical characteristics of the shield tape. The model calculated in this paper is a part of a large work research; with the results of that research we can calculate the most used electric characteristics of the pair according to the physical and geometrical characteristics of it. This research was applied in an important cable manufacturing company of the automotive sector.

Fiber Optic Sensors for Diagnosis and Maintenance in Lead-Acid Batteries

Abstract This paper presents a fiber optic sensor for use in battery maintenance and also useful in determining the battery State of Health (SoH). The sensor was originally developed for electrolyte density measurements; the sensor comprises several plastic optical fiber sensors which measure the density of the electrolyte at different heights within the vessel of the battery. The sensor is based on light loss that occurs in the detection zone by means of the variation of the density of the electrolyte. This variation depends on the state of charge (SoC) of the battery at the height at which the sensor is placed and also depends on wear-out of battery. In summary, changes in the density of the electrolyte over time are an indicator of SoH. Strategic positioning of the measuring points of the sensor also allows measurements of other variables that facilitate maintenance: detection of low level of the electrolyte and the sediment of the active material that settles into space at the bottom of the cell.