Shun-Chung Wang

A Modified PI-Like Fuzzy Logic Controller for Switched Reluctance Motor Drives

Based on the redevelopment of control rule base, two modified PI-like fuzzy logic controllers with output scaling factor (SF) self-tuning mechanism are proposed and verified in this paper for application in the switched reluctance motor (SRM) drive system. The motivation of this paper is to simplify the program complexity of the controller by reducing the number of fuzzy sets of the membership functions (MFs) without losing the system performance and stability via the adjustable controller gain. For both types of controllers, the output SF of the controller can be tuned continuously by a gain updating factor, whose value is derived from the fuzzy logic reasoning, with the plant error and the error change ratio as the input variables. The rule bases are created based on the knowledge of the SRMs dynamic behavior and practical experience. Various aspects of the design considerations about the MF, rule base, and gain tuning strategy are described in detail. Experimental results, carried out on a four-phase 8/6-pole SRM based on the dSPACE DS1104 platform, are given to show the feasibility and effectiveness of the devised methods. A performance comparison of the proposed controllers with their conventional counterpart is also included.

Software-Reconfigurable e-Learning Platform for Power Electronics Courses

An effective course in power electronics should ideally contain hands-on design and experimental work as well as theory explanation and simulations. In this paper, a software- reconfigurable e-learning platform for power electronics courses is proposed. The aim of the proposed system is to realize a platform capable of constructing a wide range of circuit topologies and control techniques, thus enabling students to gain a better understanding of power electronics converters through practical experiments. The proposed platform consists of a reconfigurable power electronics testbed, a Web-based distance laboratory, and a user interactive e-learning platform. The reconfigurable power electronics testbed can be configured by the students via a Web- based interface to construct a wide variety of converters and inverters. The Internet accessible distance laboratory system permits the instructors and students to remotely conduct experiments over the Internet. The integrated interactive multimedia material can support the educational environment of power electronics courses and can be executed on any modern personal computer (PC) without additional hardware. The advantages of the proposed platform include flexibility, friendly user interface, allow for distance waveform measurements, and removal of laboratory time and space constraints. The positive response from students indicates that the proposed platform is extremely useful for power electronics courses.

A PSO-Based Fuzzy-Controlled Searching for the Optimal Charge Pattern of Li-Ion Batteries

This paper proposes a searching strategy based on particle swarm optimization, combined with a fuzzy-deduced fitness evaluator (FDFE), to find the optimal multistage charging pattern that delivers the most discharged capacity within the shortest charging time (CT). The objective function of the optimization problem is to maximize the cost effectiveness for the applied charging pattern based on the CT and normalized discharged capacity (NDC). Therefore, this paper proposes an FDFE to combine CT and NDC into a unified cost function to properly evaluate the multiple performance characteristics index in the charge problem. The experimental results show that the obtained pattern is capable of charging the batteries to over 88% capacity within 51 min. Compared with the conventional constant current-constant voltage method, the CT, the obtained life cycle, and the charging efficiency of the lithium-ion (Li-ion) battery for the devised approach are improved by approximately 56.8%, 21%, and 0.4%, respectively. The presented charging approach is suitable for the increasingly applications, in which the batteries are “sealed” inside the products to extend the life span.

High-Power-Factor Electronic Ballast With Intelligent Energy-Saving Control for Ultraviolet Drinking-Water Treatment Systems

Over the past few decades, ultraviolet (UV) water treatment has become widely recognized and accepted by regulatory agencies as a proven disinfection process. With the increased awareness of health concerns and water quality, UV disinfection is quickly gaining popularity in the consumer market as a safe, effective, and economical approach to disinfection. In order to disinfect properly, conventional UV water-treatment systems keep their light intensity at maximum level regardless of the operating condition; this results in unnecessary energy waste along with lamp-life-span reduction. In this paper, a new design of high-power-factor low-cost electronic ballast with intelligent control for UV water-treatment system is proposed. For the purposes of energy saving, an intelligent-control algorithm is proposed to dim the luminance of the UV lamp according to the measured water flow rate and UV light intensity. Accurate knowledge of the characteristics of the UV lamps is essential for the ballast design. Therefore, an automatic identification system is also proposed in this paper to obtain the characteristic parameters, which are the dynamic and steady-state profiles of the UV lamps. Systematic design procedures are then presented accordingly. The proposed UV water-treatment system boasts the advantages, such as compactness, low cost, and energy saving, and is suitable for residential users. According to the experimental results, the energy-saving capability of the proposed system is better than 50%.

Fuzzy-control-based five-step Li-ion battery charger

Nowadays, commercial lithium-ion (Li-ion) batteries are playing important roles as supplies for mobile phones, laptop computers and other electronics. In order to maximize the performance of Li-ion batteries, advanced charger is required. The main objective of an advanced battery charger includes short recharge times, high charging efficiencies and improved battery cycle life. This paper presents the design and implementation of a dsPIC-based fuzzy five-step Li-ion battery charging system. To obtain the optimal charging performance for the Li-ion battery, fuzzy-control-based five-step charging algorithm and a simple power stage is used in the proposed system. Using this control, the performance of the proposed system can be improved. In addition to the hardware, a graphical user interface is also presented in this paper. According to the experimental results, the proposed charger is capable of charging the Li-ion batteries with higher efficiency and lower temperature rise.

Generalized Simulation Model for a Switched-Mode Power Supply Design Course Using MATLAB/SIMULINK

Switched-mode power supplies (SMPS) are becoming an essential part of many electronic systems as the industry drives toward miniaturization and energy efficiency. However, practical SMPS design courses are seldom offered. In this paper, a generalized MATLAB/SIMULINK modeling technique is first presented. A proposed practical SMPS design course at Lunghua University, Taiwan, which incorporates this technique, is then described. In order to validate the correctness of the proposed modeling technique, four prototype SMPS are provided in this paper. These prototype circuits also serve as the laboratory section of the proposed course. The main objective of the course is to teach final-year undergraduate students and first-year Masters students how to design an SMPS in real life. The positive response from students indicates that the proposed technique is useful for SMPS design courses.

Digital dimming control of CCFL drive system using pulse density modulation technique

In this paper, a digital dimming controller for the CCFL drive system is presented. The proposed digital controller utilizes pulse density modulation (PDM) technique to adjust the output power. In order to verify the correctness of the proposed method, a FPGA (Field Programmable Gate Array)-based CCFL drive system is also built and tested. The overall system power efficiency is approximately 85%. Comparing to low frequency dimming (LFD) methods, the proposed system can reduce the voltage spike by over 15%.

A novel sequential-color RGB-LED backlight driving system with local dimming control and dynamic bus voltage regulation

Higher luminance efficacy, wider color gamut, lower power consumption, faster response, longer operation life, lesser environmental impacts, and local dimming capability make RGB LED backlight driving system suitable for high end LCD applications. In this paper, a digitally controlled four-phase interleaved RGB LED backlight driving system for LCD panels is proposed. Field color sequential (FCS) techniques, local dimming control (LDC) and dynamic bus voltage regulation (DBVR) technologies are implemented in the proposed system. FCS can improve the power efficiency and image quality, LDC can reduce the power consumption and enhance the image contrast ratio and DBVR can maximize the driving systems efficiency. Only one power converter is required in the proposed system; therefore the system configuration is very simple. Finally, experimental results are provided to validate the effectiveness and correctness of the proposed system. According to the experimental results, the presented system can successfully drive the RGB LED backlight module, and the color-mixing, local dimming and bus voltage regulation functions can be successfully realized.

A modified PI-like fuzzy logic controller for switched reluctance motor drive

Based on the redevelopment of control rule base, a modified type PI-like fuzzy logic controller with output scaling factor (SF) self-tuning mechanism is proposed and experimentally testified in this paper for application in the switched reluctance motor (SRM) drive system. This paper aims to simplify the structure hierarchy and computational complexity of the controller by reducing the number of fuzzy sets in the membership function (MF) but still without losing the system performance and stability. For the proposed controller, the output scaling factor can be tuned continuously by a gain updating factor, whose value is derived from the fuzzy logic reasoning with the error and change of error of the plant as the input variables. The rule base is built based on the practical understanding and knowledge of the SRMs basic dynamic behavior, operating mode and experimental experience. Various aspects of the design considerations about the membership function, rule base, and gain tuning strategy are described in detail. Experiments and results comparison carried out on a four phase 8/6 pole SRM based on the platform of dSPACE DS1104 control desk are given to show the feasibility and effectiveness of the devised methods as well as support the theoretical considerations.

Development of DALI-based electronic ballast with energy saving control for ultraviolet lamps

A wireless DALI controlled electronic ballast for ultraviolet lamp (UVL) with high-sterilization quality and energy-saving control is proposed in this paper. Up to a maximum of 64 UVLs can be simultaneously controlled through the digitally addressable lighting interface (DALI) by the devised system to provide large-scale sterilization applications. The proposed configuration consists of a digitally-controlled electronics ballast for UV lamp, a Zigbee-based DALI bridge module for wireless control, and a remote controller for inputting the control parameters. Performance and energy-saving effectiveness of the proposed control scheme is demonstrated on a prototype experimental system.