Showing papers in "Electronics in 2012"

Implantable devices: issues and challenges

Abstract: Ageing population and a multitude of neurological and cardiovascular illnesses that cannot be mitigated by medication alone have resulted in a significant growth in the number of patients that require implantable electronic devices. These range from sensors, gastric and cardiac pacemakers, cardioverter defibrillators, to deep brain, nerve, and bone stimulators. Long-term implants present specific engineering challenges, including low energy consumption and stable performance. Resorbable electronics may offer excellent short-term performance without the need for surgical removal. However, most electronic materials have poor bio- and cytocompatibility, resulting in immune reactions and infections. This paper reviews the current situation and highlights challenges for future advancements.

Power Electronic Transformer Technology for Traction Applications – An Overview

Abstract: Combining modern high-power semiconductor devices with constantly improving magnetic materials opens up the possibility to replace bulky low-frequency transformers with a new medium voltage medium frequency conversion structure. While there are still challenges to be addressed related to these so called power electronic transformers, a steadily increasing development effort is evident and considered in various contexts. Traction applications seem to be the first ones where proliferation of these galvanically isolated power electronic converters is expected. In this application field, substantial weight and volume reduction can be achieved while providing additional functionality at the same time. In this paper a survey of recent R&D efforts in this field is presented.

Radiation Effects in Carbon Nanoelectronics

Abstract: We experimentally investigate the effects of Co-60 irradiation on the electrical properties of single-walled carbon nanotube and graphene field-effect transistors. We observe significant differences in the radiation response of devices depending on their irradiation environment, and confirm that, under controlled conditions, standard dielectric hardening approaches are applicable to carbon nanoelectronics devices.

HIL Simulation of Power Electronics and Electric Drives for Automotive Applications

Abstract: Hardware-in-the-loop simulation is today a standard method for testing electronic equipment in the automotive industry. Since electric drives and power electronic devices are more and more important in automotive applications, these kinds of systems have to be integrated into the hardware-in-the-loop simulation. Power converters and electric drives are used in many different applications in vehicles today (hybrid electric or electric powertrain, electric steering systems, DC-DC converters, etc.). The wide range of applications, topologies, and power levels results in various different approaches and solutions for hardware-in-the-loop testing. This paper gives an overview of hardware-in-the-loop simulation of power electronics and electric drives in the automotive industry. The currently available technologies are described and future challenges are outlined.

Energy Efficiency in Electric Drives

Abstract: In this paper a look at energy efficiency in electric drives is taken strongly through energy parameters - efficiency ? and power factor k (in special case cos f). Considering electric drive as system of working mashine, motor and power converter, the influence of components is evaluated. Induction motor, as the most used in industry, has been treated. The necessary of variable speed drives in dynamic states for reducing electrical losses by help of power converters is presented. The importance of energy efficiency in electric drives on improving technological process, consumed and paid electric energy and global problem of enviroment pollution is elaborated.

PWM Algorithms for Multilevel Inverter Supplied Multiphase Variable-Speed Drives

Abstract: Multiphase variable speed drives are nowadays regarded as serious contenders for various applications, due to the certain advantages that they possess when compared to three-phase drives. On the other hand, the multilevel (predominantly three-level) voltage source inverter (VSI) has become an industrially accepted technology for medium-voltage three-phase drives. The logical next step is to integrate multilevel VSI and multiphase drive technologies, since benefits of each can then be combined. This paper will review recent advances in this area. Two different topologies of the multiphase supply will be considered and the emphasis will be placed on appropriate pulse width modulation (PWM) techniques that can be used in conjunction with the supply structure. The first topology utilises multilevel (three-level) VSI and the machine’s stator multiphase winding is star-connected with an isolated neutral point. In the second topology the winding is left open-ended and each side of the winding is connected to an isolated two-level VSI. This topology can also achieve three-level operation. Carrier-based and space vector based PWM strategies are considered and the obtainable performance is illustrated using experimental results.

Bidirectional ac-dc converter for regenerative braking

Abstract: In this paper, a bidirectional AC DC converter is analyzed The converter applies a half bridge thyristor rectifier and a recuperating thyristor bridge instead of a braking resistor Recuperating mode of the converter is focused in the analysis, and it is shown that the converter exposes two operating modes within the recuperating mode, one characterized by negligible, and the other one characterized by significant distortion of the input voltages Theoretical results are experimentally verified on a 10 kW converter

Multiple Bit Error Tolerant Galois Field Architectures Over GF (2m)

Abstract: Radiation induced transient faults like single event upsets (SEU) and multiple event upsets (MEU) in memories are well researched. As a result of the technology scaling, it is observed that the logic blocks are also vulnerable to malfunctioning when they are deployed in radiation prone environment. However, the current literature is lacking efforts to mitigate such issues in the digital logic circuits when exposed to natural radiation prone environment or when they are subjected to malicious attacks by an eavesdropper using highly energized particles. This may lead to catastrophe in critical applications such as widely used cryptographic hardware. In this paper, novel dynamic error correction architectures, based on the BCH codes, is proposed for correcting multiple errors which makes the circuits robust against radiation induced faults irrespective of the location of the errors. As a benchmark test case, the finite field multiplier circuit is considered as the functional block which can be the target for major attacks. The proposed scheme has the capability to handle stuck-at faults that are also a major cause of failure affecting the overall yield of a nano-CMOS integrated chip. The experimental results show that the proposed dynamic error detection and correction architecture results in 50% reduction in critical path delay by dynamically bypassing the error correction logic when no error is present. The area overhead for the larger multiplier is within 150% which is 33% lower than the TMR and comparable to 130% overhead of single error correcting Hamming and LDPC based techniques.

Energy Efficient Sensor Nodes Powered by Kinetic Energy Harvesters – Design for Optimum Performance

Abstract: In an energy harvester powered wireless sensor node system, as the energy harvester is the only energy source, it is crucial to configure the microcontroller and the sensor node so that the harvested energy is used efficiently. This paper outlines modelling, performance optimisation and design exploration of the complete, complex system which includes the analogue mechanical model of a tunable kinetic microgenerator, its magnetic coupling with the electrical blocks, electrical power storage and processing parts, the digital control of the microgenerator tuning system, as well as the power consumption models of sensor node. Therefore not only the energy harvester design parameters but also the sensor node operation parameters can be optimised in order to achieve the best system performance. The power consumption models of the microcontroller and the sensor node are built based on their operation scenarios so that the parameters of the digital algorithms can be optimised to achieve the best energy efficiency. In the proposed approach, two Hardware Description Languages, VHDL-AMS and SystemC-A is used to model the system's analogue components as well as the digital control algorithms which are implemented in the microcontroller and the sensor node. Simulation and performance optimisation results are verified experimentally. In the development of the fast design exploration tool based on the response surface technique, the response surface model (RSM) is constructed by carrying out a series of simulations. The RSM is then optimised using MATLAB's optimisation toolbox and the optimisation results are presented.

Modeling and Design of Passive Components for Flexible Electronics

Abstract: In this paper, electromagnetic modeling of capacitors and inductors for printed electronic circuits is studied. Capacitors are successfully modeled by two-dimensional finite element software. Capacitive sensor for chemical detection is proposed and tested in water. Inductors are modeled by the integrating through the currents and obtained results have been compared with 3D finite element method. A capacitive sensor and an inductor on flexible substrate were fabricated. Simulation results have been validated through measurements.

Modified EAS Tag Used as a Resistive Sensor Platform

Abstract: In this article, a modified design of an RF Radio Frequency Electronic Article Surveillance (EAS) tag, used as a sensor platform, is manufactured and characterized. EAS tags are passive devices consisting of a capacitor and coil, tuned to a resonance frequency readable by the detector equipment, in this case 8.2 MHz. They were originally used to detect whether merchandise was being moved through the detection gates at shop exits, in which case an alarm was triggered. If the capacitance is divided in two and a resistive sensor device inserted in between, the resonant Inductor-Capacitor (LC) circuit becomes an Inductor-Capacitor-Capacitor-Resistor LCCR circuit and can be used as a sensor tag. A high sensor resistance means that one capacitor is decoupled, leading to one resonance frequency, while a low resistance will couple both capacitances into the circuit, resulting in a lower resonance frequency. Different types of resistive sensors exist that are able to detect properties such as pressure, moisture, light and temperature. The tag is manufactured in Aluminum foil on a polyetylentereftalat (PET) substrate, resulting in a cost effective RF-platform for various resistive sensors. Two types of tags are designed and manufactured, one with parallel plate capacitors and the other with interdigital capacitors. To test the tags, a resistive tilt sensor is mounted and the tags are characterized using a network analyzer. It is shown that for high resistance, the tags have a resonance frequency

Simulation of Power Electronic Converters Using Quasi Steady State Approximation

Abstract: A new method to compute voltage and current waveforms of power electronic converters is proposed in the paper. The method relies on simulation result of averaged circuit model, and superimposes the ripple of the inductor currents to the obtained average values, assuming that the linear ripple approximation applies. To determine the amplitude of the switching ripple, a quasi steady state approximation is proposed. After the inductor currents are obtained, currents of switching components are computed by multiplying them with appropriate switching functions. The algorithm provides an efficient tool to generate the converter waveforms in order to compute their spectra, mean and RMS values, which are of interest in designing filters and estimating converter losses.

Network Simulator Tools and GPU Parallel Systems

Abstract: In this paper we discuss the possibilities for parallel implementations of network simulators Specifically we investigate the options for porting parts of the simulator on GPU in order to utilize its resources and obtain faster simulations We discuss few issues which are unsuitable for the GPU architecture, and we propose a possible work around for each of them We introduce a design of parallel module that interconnects with a network simulator, while maintaining transparency in aspect of the simulation modeler

Cyber Physical Systems Approach to Power Electronics Education

Abstract: This paper proposes a Cyber Physical Approach (CPS) to power electronics (PE) education where all aspects of PE technology from circuit topology to the implementation of real time control code on a microprocessor are dealt with as an inseparable whole, and only the system complexity is increased during the course of instruction. This approach is now made practical thanks to the affordable and unrestricted access to high-power PE laboratory infrastructure (PE laboratory in a box) in the form of high-fidelity digital PE emulators with 1us calculation time step and latency.

High frequency model of EMI filter

Abstract: The EMI filters are usually used for suppression of electromagnetic conducted interference of range 9 kHz-30 MHz. The efficiency of electromagnetic interference filter is described by attenuation characteristics. The value of attenuation of EMI filter depends on main parameters of filter’s elements and its parasitic parameters. Therefore the high frequency model of electromagnetic interference filter is analyzed in this paper.

How To Measure Oscillator’s Short-Term Stability Using Frequency Counter

Abstract: In this paper a few methods of how to use frequency counter in time-domain frequency stability analysis are described. Three implemented methods are presented. As an experiment, a comparison of the realized methods in the Technical Test Center (TOC) and the “references” obtained in the Directorate of Measures and Precious Metals (DMDM) in Belgrade are accomplished. The measurement uncertainty estimation for time interval measurement with one frequency counter is presented as well.

Stabilizing Ferroresonance Oscillations in Voltage Transformers Using Limiter Circuit

Abstract: This paper employs the multiple scales method and chaos theory for analyzing chaotic behavior of the voltage transformer (VT) with linear core loss model. It is shown that ferroresonance phenomenon in VTs can be classified as chaotic dynamics, including a sequence of bifurcations such as period doubling bifurcation (PDB), saddle node bifurcation (SNB), Hopf Bifurcation (HB) and chaos. Bifurcation diagrams and phase plane diagrams are drawn using a continuation method for linear core loss model and lyapunov exponents are obtained using the multiple scales method. At first an overview of the subject in the literature is provided. Then, ferroresonance phenomenon is introduced and its various types in a VT are simulated. Finally the effects of ferroresonance suppression circuit on stabilizing these oscillations are studied. The proposed approach is implemented using MATLAB, and simulation results are presented. The results show connecting the ferroresonance suppression circuit to the system configuration, causes great controlling effect on ferroresonance overvoltage.

Design of a Bioelectronics Hybrid System in Real Time and in Closed Loop

Abstract: Hynets, for Hybrid (living-artificial) Networks, are an efficient and adaptable experimental support to explore the dynamics and the adaptation process of biological systems. We present in this paper an innovative platform performing a real-time closed-loop between a cultured network (e.g. neurons) and an artificial processing (e.g. software processing or a robotic interface). The system gathers bioware, hardware, and software components and ensures the closed-loop data processing in less than 50 µs. We describe also a methodology that may help to standardize the description of some experiments. This method is associated to a full custom Graphical User Interface. We detail here the system choices, components, and performances.

Analysis of Single Coil PM-BLDC

Abstract: The aim of the paper is FEM analysis of single coil BLDC motor operated as drive of small piston pump. The paper contains analysis of design, distribution of magnetic field, forces and torque under static and dynamic conditions. Voltages, currents, signals waveforms are also given as the results of analysis. The cogging torque and total torque are discussed in the paper.

Some Examples that Use the FEM in PM Generators Analysis

Abstract: The present paper refers to some examples that use the finite element method (FEM) in the process of analysis, design and optimization of the permanent magnet (PM) generators used in wind applications. The 2D-FEM program Opera 13 of Vector Fields is used in the analyzed examples. These examples refer to two types of radial flux low speed PM generators of 5 KW for wind applications. Some possibilities of electrical machine optimization, using the FEM-programming packages available today, are pointed out during the present paper.

Designing Energy Conversion Systems for the Next Decade

Abstract: Sustainable growth in energy consumption requires transition to clean and green energy sources and energy systems. Environment friendly and renewable energy systems deal with electrical energy and rely on efficient electrical power converters. High power electronics is the key technology to deal with the next generation of electrical energy systems. The door to future breakthroughs in high power electronics is opened by major improvement in semiconductor power devices and their packaging technologies. New materials allow for much higher junction temperatures and higher operating voltages. Most importantly, advanced power semiconductor devices and novel converter topology open the possibility to increase the energy efficiency of power conversion and reduce the amount of heat. Although the waste heat created by high power converters can be put to use by adding on to heating systems, this option is not always available and the conversion losses are mostly wasted. At the same time, wasted heat is a form of pollution that threatens the environment. Another task for high power converters is efficient harvesting of renewable energy sources, such as the wind energy and the sun. Intermittent in nature, they pose a difficult task to power converter topology and controls. Eventually, high power converters are entering power distribution and transmission networks. With their quick reaction, with fast communication between the grid nodes and with advanced controllability of high power converters, a number of innovations can be introduced, facilitating the power system control and allowing for optimizations and loss reduction. Coined smart grid, this solution comprises two key elements, and these are intelligent controls and large static power converters. At virtually no cost, smart grids allow for a better utilization of available resources and it enlarges the stable operating range of the transmission systems. Therefore, it is of interest to review the future trends in designing high power converters.

Data Privacy in Smart Electricity Networks

Abstract: Smart Grids are amongst the most promising future developments to manage and control the energy consumption in the next decades. However, the integration and interdependencies that will evolve between the electricity power grid, telecommunication networks and ICT enable new threats and vulnerabilities to this critical infrastructure which must be addressed adequately with the right kind of security controls, balanced risk mitigation strategies and a continuous attention towards security, privacy and regulation aspects. It is an emerging area where new data privacy problems arise as mass rollout of smart meters is already happening.

Advanced DC Motor Drive for Haptic Devices

Abstract: Haptics covers many different forms of mechanical interaction with human senses by engaging, touch, vibrations and forces/torques, established for the purpose of augmenting the feedback structure during human-machine interaction. A haptic device has mechanical part, moved by actuators from one and human hand or fingers from the other, actuators, drives, sensing elements, as well as algorithms designed to control the interaction between human and machine in positioning and motion control tasks. With such a system, motors can be controlled in a way to simulate various environments, defined by their material and dynamics, for example pushing soft ball uphill. Haptic devices are becoming more popular in medical applications after introduction of modern medical robots with many different extensions for minimally invasive surgery or diagnostics based on palpation. This paper discusses one DC motor driver custom designed for the purpose of designing a haptic device for medical applications.

Influence of a Thin Copper Shield on a BLDC Motor Parameters

Abstract: A simplified model of a brushless DC motor segment is studied in this work. Shielding of the ferromagnetic structure with a high conductivity layer is explored. The shield is supposed to reduce the ohmic losses of the magnets and of the entire structure, particularly at the higher frequencies. In order to verify that, both calculations and measurements of the power loss are accomplished for the model first. In conclusion, locked rotor measurements are performed on a real BLDC motor in order to validate the results.

Pattern-Based Approach to Current Density Verification

Abstract: Methodology of static verification of current density based on layout patterns common in IC designs is proposed. The methodology is based on pre-calculation of current density distribution for common layout patterns. Then using the obtained data to calculate current densities of large circuits by partitioning them to selected patterns. Presented experimental results show the effectiveness of the approach.

The Decomposition of DSP’s Control Logic Block for Power Reduction

Abstract: The paper considers the architecture and low power design aspects of the digital signal processing block embedded into a three-phase integrated power meter IC. Utilized power reduction techniques were focused on the optimization of control logic block. The operations that control unit performs are described together with power optimization results.

IPMSM Model Including Magnetic Saturation and Cross-Coupling

Abstract: This paper presents a modified IPMSM model suitable for use with carrier-signal-injection-based sensorless methods. The suggested model includes magnet saturation of both d- and q- axis and cross-coupling which all result in more accurate description of high frequency test signal propagation. The model is verified by comparing experimental results of a sensorless method based on HF test signal with simulation results from standard and modified model.

Comparison of Methods for On-Line Harmonic Estimation

Abstract: The aim of this paper is to present a comparison of some popular methods for online harmonic estimation. The well-known methods Descrete Fourier Ttransform (DFT), Enhanced Phase Locked Loop (EPLL), Adaptive Notch Filter (ANF) and method based on Extended Kalman Filter (EKF) are simulated and compared. The methods are compared in critical phases, such as the fast change of harmonic amplitudes and the change of the system frequency.