Showing papers presented at "International Conference on Power Electronics Systems and Applications in 2006"

General Study for using LED to replace traditional lighting devices

Abstract: High power LED provides a high luminous and high efficient for using as a lighting source. Because of the advent for LED as lighting device, LED lighting becomes one of the new trends in the lighting industry. In this paper, the power circuit design based on the constant current flyback and the heat distribution matter are discussed. The aims of the work are provide a solution for using LED to replace the traditional lighting device.

A Novel Detection Method for Voltage Sags

Abstract: Determining the start and end of the voltage sag event is very important for sag analysis and mitigation. There are several detection methods for voltage sags in which sag voltages are usually expressed in the terms of RMS. The RMS method represents one cycle historical average value, not instantaneous value which may lead to long detection time when voltage sag has occurred. This paper will proposed a novel voltage sag detection method based on miss voltage technique. Proper dead-band and hysteresis are used in the method. The actual instantaneous voltage is compared with certain percentage of desired grid voltage and certain percentage of the amplitude of the grid voltage. Through instantaneous value comparison, low instantaneous value of the grid is shielded which overcome the mishandling turnover of voltage sags. The approach is fully described, and the results are compared with other methods for marking the beginning and end of sag, such as RMS value evaluation method and Peak-value method and simulation result provides that the method is efficient and fast and can be used to determine the initiation and recovery of voltage sags accompanied by missing voltage technique.

Tapped inductor for switched-mode power converters

Abstract: The tapped converter of the classical switched-mode power converter is an extension of the conventional switched mode power converters Using the tapped configuration, the control parameter of the converter can be used as tapping It is found that the conversion has a very wide range of variation as compared with before The paper introduces this basic concept to give readers a broader understanding of this classical method of power conversion

DC Electrical Distribution Systems in Buildings

Abstract: With the gaining of popularity of concept of distribution generation (DG) and sustainable development, DG with renewable energy (RE) sources is one of the possible ways for building energy supply in the future. The current "DC-AC-DC" route from DG to DC loads via inverters may not be rational from the viewpoint of system simplicity and energy efficiency, a review on the current electrical distribution systems should be made. This paper reviews and evaluates possibilities of using DC electrical distribution systems with increasing RE resources and DC loads. There is potential of increasing energy efficiency and power quality. Drawbacks and merits will also be identified.

Study on Magnetic Materials Used in Power Transformer and Inductor

Abstract: Power electronics system is generally comprised of electrical and magnetic circuits. Nowadays, there were a lot of research works on circuit topologies ranging from single switch converter to soft-switching topologies, but the most difficult problems encountered by many design engineers were magnetic issues, such as construction of transformer or inductor, application of air-gap, under- or over-estimated power rating of the magnetic components, selection of magnetic core and so on. The overall performance of any power converters depend on not only the circuit design, but also the application of magnetic components, this paper will address some common problems related to the applications of magnetic components, and some critical factors involved into development of such components for power converters. A brief summary of some major magnetic materials, such as soft ferrites, powder iron and alloys will be mentioned in this paper too.

A Control Scheme of Torque Ripple Minimization for SRM Drives Based on Flux Linkage Controller and Torque Sharing Function

Abstract: This paper presents a new control scheme to implement the torque ripple minimization in switched reluctance motor drives. The proposed scheme uses the nonlinear torque sharing function in which two active phases contribute the torque during phase commutation and the torque at other time is produced by an active phase. The flux linkage controller with the hysteresis chopping is employed to trace the flux linkage reference computed from the torque sharing function. The simulations on a four-phase switched reluctance motor drive demonstrate that the proposed control scheme can be used to well implement the torque ripple minimization. Comparing with conventional current controllers, the limit on the proposed flux controller is easily determined and the saturation of the flux linkage controller may be avoided.

Maintenance techniques for rechargeable battery using pulse charging

Abstract: The objective of this paper is to investigate a charging method control techniques for charging lead-acid battery. The characteristics of lead-acid battery are presented that include the charging method affecting the capacity of battery. The conventional charging method is pointed out the merit and drawback. And also the variable pulse width charging is also presented in this paper. This method is modified from the conventional method to enhance the life cycle and capacity.

General study for design the HID ballasts

Abstract: High-intensity discharge (HID) lighting lamp systems are widely used in applications that can provide a high light levels are desired for large areas, such as vehicle headlight, industrial and street lighting. Similar to fluorescent lighting systems, all HID lighting systems require a ballast to operate. Traditionally, magnetic ballast designs were the only choice available for HID lighting systems. Today, high-efficiency electronic HID ballasts are available that provide improved lighting quality and reduce lighting electricity use by 10 to 30 percent. The purpose of this paper is to identify requirements of the ballast interface from the perspective of the HID lamp. This study will generally brief the starting, run-up, and steady state operation of HID lamps on electronics ballasts.

Design and fabrication of freeform reflector for automotive headlamp

Abstract: Modern automotive illumination systems require higher efficiency, safety, and good aesthetic features. The design, fabrication and measurement are critical issues for automotive illumination systems. The non-imaging optical design for the automotive lighting system, which departs from the methods of traditional optical design, is an arisen interdisciplinary field. In order to meet the traffic regulations, unique freeform shapes and geometries should be adopted to create the special legal light pattern. Mean while, high accuracy freeform reflector could not be made by conventional manufacturing process, ultra-precision machining is the method. And the measurement of the freeform surface is also a new area. In this paper, the optical design, fabrication and the measurement of the freeform reflector headlamps are investigated.

An Energy-Saving Scheme of Variable Voltage Control for Three-Phase Induction Motor Drive Systems

Abstract: This paper presents a control scheme to implement the energy-savings of three-phase induction motors when they operate under long-term light-load or small duty ratio load. The proposed scheme is based on the principle of variable voltage control (VVC) at constant speed. The energy-saving controller for three-phase induction motors is developed. A group of the experiments demonstrate that the proposed scheme gives rise to the considerable energy-savings.

Variable Gain Intelligent Control of Multi-motor Synchronization System

Abstract: Multi-motor synchronization control (MSC) is a key issue in industrial production Based on the conventional PID algorithmic, a variable gain intelligence control scheme is proposed in this paper Consequently, this new idea was implemented by PLC controller in the stretch tension & synchronization control system of a wide-fabric heating-shaping machine Such a system has perfect characteristics, eg rapid response, overshoot-less and no steady-state errors In addition, easy programming, simple wiring and strong anti-jamming ability lead to a stable operating performance The proposed scheme can be widely used in electrical motor synchronization control demands arising from the spinnery, paper mill and mechanical production lines

Improvements in the Mechanical Structure of the Linear Switched Reluctance Motor

Abstract: In semiconductor manufacturing, wire bonding of chips and surface mount technology process require precise robotic linear motion. Traditionally, X-Y sliding tables driven by permanent magnet rotary motors, ball-screw and belt are used. However, they have position accuracy problem due to ball-screw backlash. Since motors and high precision grade ball-screws are expensive, high manufacturing cost is another disadvantage. Low reliability results from complex mechanical alignment and low ball-screw lifetime. This paper presents the basic structure of linear switched reluctance motor for high performance motions in manufacturing automation. No magnet is used and the traveling distance has no limitation. Consequently, this motor is extensively robust and applicable in hostile environment. A two-dimensional motor is introduced to replace the conventional X-Y table. Based on switched reluctance driving method, the proposed actuator has a very simple and robust structure with very few mechanical parts for easier manufacturing. 3 designs are compared on their mechanical structure and efficiency. Detailed motor framework description and corresponding mathematical model are shown. Applied control theory would be mentioned.

Shunt Active Power Filter - SIMULINK Simulation and DSP-based Hardware Realization

Abstract: Active power filter (APF) is one of the effective means for harmonic current compensation in power grid. This paper focuses theoretical topics on a three-phase four-wire shunt active power filter (SAPF) system, covers operation principle, harmonic current detection, structure of main circuit, control of the DC voltage and compensating current. The overall system has been modeled using MATLAB/Simulink, and simulation results have shown that the structure is reasonable. Besides, the SAPF control system's hardware is realized based on DSP and MCU.

A Practical Dynamic Phasor Model of Static VAR Compensator

Abstract: This paper presents a three phase dynamic phasor model of static VAR compensator which takes fundamental and fifth harmonic into consideration. The modelling approach is based on the time-varying Fourier coefficient series of the power system variables. By truncating the less important higher order terms and keeping the significant ones, the new dynamic phasor model can realistically simulate the dynamic behaviour of SVC with fast speed and high accuracy. Without any simplified assumption, the new model is applicable to fast numerical simulation of SVC. Computer simulation results show the accuracy and efficiency of the dynamic phasor model of SVC.

Recent Projects of Building Integrated Photovoltaic in Hong Kong

Abstract: In Hong Kong, a number of medium-scale Building Integrated Photovoltaic (BIPV) systems were completed in last few years These BIPV projects included government building, commercial building, schools, institutional building The power rating the BIPV system for each project is in the order of tens of kilowatts Most of these BIPV systems are gird-connected type to eliminate the bulky and troublesome battery banks Some of these projects are retrofitting on existing buildings; while some are parts of a new building The paper will give details on the design of these PV systems in Hong Kong, including system configurations, design considerations, protections, grid-connection interfacing, power quality issues, their performance, technical difficulties encountered, and experience gained

Examination of T8-T5 Electronic Ballast Adaptor

Abstract: This paper presented an examination of conversion from T8 conventional fluorescent lamp into a T5 lamp with electronic ballast. Without changing the T8 fixture, a T5 fluorescent lamp can be fitted into the fixture with a T8-T5 electronic ballast adaptor, which provides both power factor correction (PFC) and high frequency switching. The power factor of the overall lighting system was regulated to be 0.98, and the electrical efficiency was 95%. All these features cannot be achieved with the conventional magnetic ballasts.

Impact of Source Voltage Unbalance on AC-DC Rectifier Performance

Abstract: This paper presents a comprehensive study about the impact of source voltage unbalance on the performance of a three-phase ac-dc rectifier along with the harmonics injected by the rectifier load. The variation of different characteristic and non-characteristic harmonics with the degree of unbalance is investigated. The study also includes the effect of source voltage unbalance on harmonic distortion of different input and output characteristics of the rectifier. Since, the voltage sequence components play an important role in describing a more clear view of degree of voltage unbalance, an attempt has been made to identify the impact of sequence voltage components on total harmonic distortion and individual harmonic components in different phases. A full understanding of sensitivity of the current harmonic components to different unbalance voltage operating conditions is also obtained. To describe the unbalance in Total Harmonic Distortion of current (THDI) in three different phases, a new term "Phase Total Harmonic Distortion Unbalance Factor" (PTHDUF) is introduced. It was found that PTHDUF is proportional to the degree of unbalance /Voltage Unbalance Factor (VUF).

Study of Intermittent Bifurcations and Chaos in Buck-Boost Converters with Input regulators

Abstract: This paper presents two series of models in the buck-boost converters with input regulators under peak current mode control. Stroboscopic maps are derived to describe the dynamical behaviors of buck-boost converters with input filter capacitor. In terms of the developed discrete maps, fast scale instabilities in buck-boost converters are studied. Numerical results reveal the circuit system exhibits distinguishing nonlinear phenomena, i.e., intermittent bifurcations and chaos. In addition, the periodicity of the intermittent behaviors is also analyzed in detail.

Temperature Dependence of Magnetic Properties of a Polymer Bonded Magnetic Material

Abstract: Polymer bonded magnetic materials have recently attracted increasing attention from fundamental research to industrial applications in many electromagnetic devices. It is necessary to investigate the properties of these magnetic materials operated under different environmental conditions. In particular, in this work, we investigated the relationship between the temperature and the magnetic properties of a polymer bonded magnetic material, epoxy (EP) resin bonded Co-Ni magnetic material. Experimental results indicate that the coercivity, the remanence magnetic flux density and the saturation magnetic flux density decrease at the elevated temperature. It is envisioned that the present studies may offer guidance for the applications of the polymer bonded magnetic material.

General Discussion on Dimming Control Method Used for Discharge Lamp

Abstract: In order to reduce the energy, the dimming control is used in the lighting system. There are many different control methods in the fluorescent lamp, after comparing these methods, a research scheme of dimming control used in the HID ballast is proposed. In addition, the lamp model, dimming range and stability analysis are also analyzed in this paper.

Development of Packaging and Electrical Interfacing for Electrical Vehicles

Abstract: Electric vehicle becomes more and more popular today. Not even major car manufacturers, small vehicle manufacturers are also developing electric vehicles. How to design a good electric vehicle? A good electric vehicle has high power efficiency, which can drive the vehicle to the maximum travelling distance between battery recharging. A series of electric vehicle has been examined, designed and tested. The design including battery, motor and gear. A prototype based on electric motor, battery and light body design has been developed. The vehicle is designed to be of low motor power and low speed operation.

Study of Dimming Control Methods For HID Automotive Lamps

Abstract: HID lamps offer better efficacy than halogen lamps and hence many cars are being fitted with metal halide HID lamps. The lamps are operated at 35 W in automobiles in all driving conditions. The present paper proposes for the first time the techniques to achieve dimming control by operating the lamp at reduced power to save energy in low-beam driving. The paper investigates the merits of each method and discusses the practical issues for implementing such a control.

A Practical Intelligent Home System Based on Power Line Communication

Abstract: This paper presents a practical, cost-effective intelligent home system based on power line communication, in which manual keypad control, speech control and GSM/GPRS remote control are implemented In this system, speech control is for old men and handicapped people who are unable to operate home appliances A focusing fuzzy template matching algorithm is proposed to improve the accuracy of speech recognition under noisy background GSM/GPRS remote control makes operation of home appliances and home surveillance feasible anywhere Because of the implementation of power line communication technology, no rewiring is required, thus making the installation of such system simple, low-cost and efficient, which is favorable for the popularization of intelligent home An experimental mini intelligent system is presents in the end

The Parameters Identification and Validation for IGBT Based on Optimization Algorithm

Abstract: IGBT (insulated gate bipolar transistor) is becoming more and more popular in many power applications, since it offers a good compromise between on-state loss, switching loss and easy of use. To develop circuits and systems using theses devices, model and model parameters are needed for use in circuit simulations. This paper presents a procedure for identifying the most IGBT models parameters. As an example, the results of identified parameters of BUP302 are given. Based on the identification, the paper presents the method for parameters validation. At last, the conclusion was given.

Research on Polymer-Bonded Magnetic Materials for a buck converter

Abstract: There is currently a need of magneto-electrical apparatus such as inductor and transformer that operate at hundreds of kHz up to several MHz, or even higher frequency The material based on polymer-bonded magnetic powder has a feature of the magnetic property and can be used as the power transformer, electromagnetic interference shielding, and power inductor, etc It is so promising that this material has been found good results for power conversion and screening In this work, a magnetic ring core was fabricated using the composite of the magnetic powder and polymer, nickel, rare earth materials and poly(methyl methacrylate) (PMMA) This ring core was used as the output filter in a buck converter, and the electrical properties were studied

Neural Network Hysteresis Control of three-phase Switched Capacitor Active Power Filter

Abstract: The switched capacitor active filter is different from the traditional active filter. It removes the requirement for a large current or voltage source, which leads to the reduction in cost and in physical size. A control method that combines the neural network technology with the hysteresis band technology is presented. Through training the neural network can learn the control rules by itself and can replace the real hysteresis comparator in power converter control. The computer simulation results show this filter's advantage.

Adaptive Passivity-Based Control of Extended-Period Quasi-Resonant Converters

Abstract: An adaptive passivity based control scheme is proposed for the stabilization of average model of extended-period quasi-resonant (EPQRC) power converter. The output load of the converter is assumed constant but unknown. A generalized state space average model of a buck-type series-mode extended-period quasi-resonant converter (SM-EPQRC) is derived. The adaptive controller is designed based on the derived model and the passivity-based control (PBC) technique. Simulation results are presented to illustrate the features of the proposed controller.

Laminated Iron Core Inductor Model with Flux Skin Effect

Abstract: In this paper, we propose a model with flux skin effect to represent the behavior of laminated iron core inductors that are used in switching converters, i.e., for excitation frequencies above several kilohertz. Modeling results show that, the inductor reactance calculated as functions of frequency, laminated thickness, core conductivity and permeability and flux skin effect in the laminated core, causes decreasing in the reactor inductance at high frequencies.

New Three-Level Voltage Source Inverter with Different 25 Space Voltage Vectors

Abstract: This paper presents a new switching strategy controlling a new three-level voltage source inverter, resulting in different 25 space voltage-vectors. The new inverter combines some desirable features of two and three-level inverters. The proposed open-leg switching strategy (OLSS) intentionally opens one of the three inverter-legs per-time, in a pre-planned sequence. Thus, the number of allowed switching states becomes 64 compared to 27 originally proposed by other modulation strategies. For a wye-connected load operating at low modulation index (M<0.5 p.u.), the output phase-voltage becomes a seven-level, 12-step waveform, instead of the 6-step one. Thus, the total harmonic distortion is highly reduced. Three new conduction-modes are presented, each verifies a reduced common-mode-voltage time-variation (dv/dt), low third harmonic content, and reduced switching frequency harmonics. For higher modulation indexes, a fourth conduction mode is presented, eliminating the low frequency harmonics in the neutral-point current, consequently reducing the dc-link capacitors sizes, and cost. Analytical models, computer simulation results, and experimental verification are presented.

Performance Study on Smart Piezoelectric Transformers

Abstract: The attractiveness of the smart piezoelectric technology is mainly due to its desirable features of miniaturization and the extreme simplicity of the resulting components compared to widely used wire wound conventional magnetics. As a result, much attention has been focused on the application of PETs in high frequency switching power supplies as well as low profile inverters. In this paper, performance study on Rosen-type, multilayer piezoelectric transformer (PET) as a potential component for power electronic conversion is presented. The equivalent circuit and impedance response of PET is studied using impedance analyzer HP4192. The effects of load resistance on voltage gain, output power and resonance characteristics are studied using simulations and experimentally under sinusoidal excitation conditions. A sinusoidal source using simple laboratory equipments and a power operational amplifier (POA) is fabricated. The details of this sinusoidal source are also given.