Adaptive Neuro-Wavelet Control for Switching Power Supplies

The switching power supplies can convert one level of electrical voltage into another level by switching action. They are very popular because of their high efficiency and small size. This paper proposes an adaptive neuro-wavelet (ANW) control system for the switching power supplies. In the ANW control system, a neural controller is the main controller used to mimic an ideal controller and a compensated controller is designed to recover the residual of the approximation error. In this study, an online adaptive law with a variable optimal learning-rate is derived based on the Lyapunov stability theorem, so that not only the stability of the system can be guaranteed but also the convergence of controller parameters can be speeded up. Then, the proposed ANW control system is applied to control a forward switching power supply. Experimental results show that the proposed ANW controller can achieve favorable regulation performance for the switching power supply even under input voltage and load resistance variations     

Plane electromagnetic wave scattering by transversely magnetized ferrite cylinder

The paper is devoted to the problem of scattering of plane electromagnetic wave by transversely magnetized ferrite cylinder. Exact analytical expressions for all partial cylindrical modes are obtained by solving Maxwell’s equations for transversely magnetized ferrite medium in cylindrical coordinate system. They are represented as the power series expansion and then are used to formulate and to solve the boundary problem. Numerical calculations of scattering patterns are also presented. Particular attention is paid to the possibility to control the scattering pattern by the external magnetic field.     

Soft-switched DC/DC converter with PWM control

In this paper, a new power converter with two variations is proposed. A novel asymmetrical pulse-width-modulation (PWM) control scheme is used to control the power converter under constant switching frequency operation. The modes of operation for both variations are discussed. The DC characteristics, which can be used in the design of the power converters, are also presented. Two 50 W power converters were built to verify the characteristics of the converters. Due to the zero-voltage-switching (ZVS) operation of the switches and low device voltage and current stresses, these power converters have high full- and partial-load efficiencies. They are, therefore, potential candidates for high-efficiency high-density power supply applications     

The semiconductor roadmap for power management in the newmillennium

Power management holds the key to over $400 billion annual savings in electrical energy and is relieving critical bottlenecks in the Internet backbone, Internet appliances and portable electronics. The latest analog integrated circuits and power semiconductors are enabling these improvements. This paper focuses on these leading-edge devices, used in conjunction with innovative architectures. The authors examine future trends in silicon-based power transistors and diodes and discuss how the changing requirements of end users are driving new analog ICs, as well as different power management architectures. Trends in architecture for DC-DC power conversion and motion control set the stage for improvements needed and planned in the power management products over the next several years. They examine various technologies for analog ICs and their interface with the digital world. They also compare the pros and cons of different techniques and levels of “power-plus-control integration”. The discussion on power MOSFETs (including IGBTs) focuses on performance and technology trends in DC-DC power conversion and motion control. State-of-the-art and future device topologies are presented. The future of diodes is also discussed. DC-DC conversion and motion control is the context. State of the art and future device topologies are presented. Less than 25% of all the world's electricity is efficiently managed. Roadmaps must focus not only on making existing applications more efficient and cost-effective, but also on enabling the new applications that can address the remaining 75%     

复信号功率估计的高效算法及其优化

该文讨论了用于含噪复值信号功率估计的两种结构简单、计算高效、可具有预测特性、可保证输出估计恒为正值的功率估计系统。功率估计的偏差和方差可以通过优化设计FIR子系统来达到最小或减小。用于移动通信CDMA系统功率控制的仿真表明:控制能力提高,低信噪比时系统差错率下降。     

Performance study for a microcell hot spot embedded in CDMAmacrocell systems

The code-division multiple-access (CDMA) system can provide more capacity than other systems, and the hierarchical layer of cells is required for system design. However, the problem is whether the same radio frequency (RF) channels used in a CDMA overlayed/underlayed macrocell and microcell structure also obtain a high capacity as in the homogeneous structure. We investigate the interference of uplink and downlink from both the microcell and macrocell under a hierarchical structure. A downlink power control scheme and two power control methods for the uplink are also considered. Performance measures such as blocking probability, C/I, capacity, and service hole area are also obtained by computer simulation. Besides, some extra efforts for a microcell are also noted, such as more power need to be transmitted by a microcell base station (BS) if the same RF channels are used in the hierarchical structure. The capacities of macrocell and microcell in the overlaying/underlaying structure are limited by the uplink and downlink, respectively. With downlink power control, the microcellular capacity can be increased. However, the combination of downlink power control for the microcell and C/I uplink power control for the macrocell causes the overall system capacity to significantly increase     

Blackout Prevention in the United States, Europe, and Russia

Tens and hundreds of thousands of disturbances occur annually in modern power systems. The overwhelming majority of them are eliminated by relay protection devices and other automatic systems and by the actions of the dispatching personnel. A small fraction of the emergencies (tens of cases in such large power interconnections as those in the United States and Canada, Europe, and the United Power System (UPS) of Russia) result in significant system failures, sometimes of a cascading nature. They are consequences of unusual primary disturbances, failures of automatic emergency control systems, protection device malfunctions, and errors by personnel, but do not cause extreme consequences for the power system and the consumers. Of these, only some rare failures-blackouts-become catastrophes with severe long-term consequences for the national economies and population. Recent blackouts in North America, Europe, Russia, and other countries require specialists once again to pay closer attention to the blackout phenomenon. It is often believed that the philosophy of preventing blackouts should be based on dispatching personnel training, wide-area system visibility,and better computer models for the analysis of the stability and security of power systems. The authors of this paper also think that in emergency situations of a cascading nature, automatic emergency control systems should play a major role. A confirmation for this statement is the fact that from 1975 to 2005 there were no blackouts in the UPS of Russia (where automatic emergency control systems are widely used). At the same time, the Moscow blackout demonstrated that the growing problems in the Russia's UPS (such as aging equipment and load growth) made it also vulnerable to major blackouts. This stresses again that the electrical power industry faces common global problems and that a global effort, cooperation, and exchange of the best practices are needed to prevent blackouts. This paper describes the Russian     

单片机应用系统的抗干扰技术

单片机控制系统已得到广泛应用,在应用现场存在着各种各样干扰源,他们对单片机应用系统的工作会产生很大影响。这些干扰可能来自应用系统自身,也可能来自供电系统、宇宙空间和工业现场。为了保证控制设备工作的安全可靠,在应用系统设计时就必须考虑到系统的抗干扰性能。分析了单片机应用系统中的干扰源、干扰途径和干扰对设备工作的影响,给出了抗干扰的硬件技术和软件技术,并介绍了看门狗的使用。工程实践中常将几个方面技术综合起来应用。     

A complete DC and AC analysis of three-phase controlled-current PWMrectifier using circuit D-Q transformation

A recently proposed circuit P-Q transformation is used to analyze a three-phase controlled-current PWM rectifier. The DC operating point and AC transfer functions are completely determined. Most features of the power converter are clearly interpreted. They are: (1) the output voltage can be controlled from zero to maximum; (2) the system is equivalently an ideal current source in the steady state; (3) the system can be described as linear circuits; and (4) the input power factor can be arbitrarily controlled within a certain control range     

高功率横流CO2激光器集散控制系统的研究

本文研究了一种用于高功率横流CO2激光器的集散控制系统。该系统兼具监测、控制、报警、保护四大功能。同时该系统在对激光器最重要的参量输出激光功率的检测研究方面,有其重要进展,该系统研制了一种新型的围内尚未解决的尾镜取样功率檎测法,该检测方法线性度好,可实现对激光功牢的实时检测叉不影响激光输出。     

Analysis and Design of a Modular Three-Phase AC-to-DC Converter Using CUK Rectifier Module With Nearly Unity Power Factor and Fast Dynamic Response

In this paper, the analysis and design of a modular three-phase ac-to-dc converter using single-phase isolated CUK rectifier modules is discussed based on power balance control technique. This paper analyzes the operation of a modular converter as continuous-conduction-mode power factor correction (CCM-PFC). Design equations, as well as an average small-signal model of the proposed system to aid the control loop design are derived. It is used to obtain the inductor current compensator, thus the output impedance and audio susceptibility become zero, and therefore, the output voltage of the converter presented in this paper is independent of the variations of the dc load current and the utility voltage. The control strategy consists of a single output voltage loop and three-inductor current calculator. The main objective of the proposed system is to reduce the number of stages and improve dynamic response of dc bus voltage for distributed power system. The proposed scheme offers simple control strategy, flexibility in three-phase delta or star-connected, simpler design, fast transient response, good inductor current sharing, and power factor closed to unity. Both simulation and experimental results are presented. They are in agreement with the theoretical analysis and experimental work.      

基于DSP的导引头伺服平台控制器系统电源设计

由于目前高性能DSP系统在降低功耗的同时必须考虑其外围器件的电源特性,所以对DSP系统电路提供电源时必须要考虑到DSP两种电压的供电特性。介绍一种基于DSP的导引头伺服平台控制器电路的电源设计方案。详细给出采用高效率的电压转换芯片为DSP提供核电压、I/O接口电压的应用电路;并设计电源监控与复位电路,以确保供电系统的稳定、可靠和高效。测试表明该电源系统具有较强的实用性和通用性,可以应用于一般的数字伺服控制系统。     

A fast dynamic DC-link power-balancing scheme for a PWMconverter-inverter system

The authors propose a new power converter control scheme for a converter-inverter system. The strategy is to fully utilize the inverter dynamics in controlling the converter dynamics. The authors obtain the power dynamics for both converter and inverter systems, and control the converter power so that it matches the required inverter power exactly. Then, in the ideal case, no power flows through the DC-link capacitors and, thus, the DC-link voltage does not fluctuate even though a very small amount of the DC-link capacitance is used. In forcing the converter power to match the inverter power, the authors utilize the master-slave control concept. They control the DC-link voltage level indirectly through the stored capacitor energy in order to exploit the advantage of the linear dynamic behavior of the capacitor energy. This helps them to circumvent a complex control method in regulating the DC-link voltage. Through simulation and experimental results, the superiority of the proposed converter control scheme is demonstrated     

Forward Link Power Control Strategy and its Optimum Issue in CDMA Cellular Networks

In this paper, we propose a theoretical method in order to estimate the forward link outage probability and user capacity of a cellular system which are based on IS-95 CDMA standard, especialy impact of power control strategy and voice activity monitoring in the system under long-term fading effects, in which the light and heavy fadings are considered. According to the numerical results obtained in this paper, the power control strategy leads to approximately the threefold user capacity in contrast to the situation without power control strategy. The reults are compared with Interference-to-Signal Ratio (ISR) driven power control scheme[6][9] which can be used only for simulation of the system. The power control strategy not only improves the desired signal to the interference ratio in the reference user's receiver, but also offers uniform service to the user wherever it is located in the cell.     

Channel access algorithms with active link protection for wirelesscommunication networks with power control

A distributed power-control algorithm with active link protection (DPC/ALP) is studied in this paper. It maintains the quality of service of operational (active) links above given thresholds at all times (link quality protection). As network congestion builds up, established links sustain their quality, while incoming ones may be blocked and rejected. A suite of admission control algorithms, based on the DPC/ALP one, is also studied. They are distributed/autonomous and operate using local interference measurements. A primarily networking approach to power control is taken here, based on the concept of active link protection, which naturally supports the implementation of admission control. Extensive simulation experiments are used to explore the network dynamics and investigate basic operational effects/tradeoffs related to system performance     

高工作温度红外探测器的研究进展及趋势

基于高工作温度探测器的热成像系统的典型特征是体积小、重量轻、功耗低,其性能在降低成本的同时与低温制冷型热成像系统的性能相当,有着重要的应用价值和批量生产的前景。本文介绍势垒型探测器的结构特点,阐述构建势垒型探测器的材料结构类型与其对系统性能的影响,总结其他相关技术实现的高温探测器。最后对势垒型探测器目前的研究进展进行归纳,提出了几个高温探测器技术未来的研究方向。     

Performance Analysis of Wireless Multimedia DS/CDMA Communications with Power Control and Hybrid ARQ

In this paper, we present aperformance analysis of a wireless multimedia direct-sequence code-divisionmultiple-access(DS/CDMA) system based on different error control schemes and an optimal power control algorithm over multipath Rayleigh fading channels.The error control schemes consist of Forward Error Correction (FEC), diversity, and Automatic Repeat reQuest (ARQ). The concatenated codes with a Reed–Solomon outer code andconvolutional inner code are used as FEC. Since a multimedia system is required to support services with different rates and Quality of Services (QoS), different error control schemes are used to satisfy the requirements of different media. In particular, a power control algorithm which can optimize the capacityperformance of the integrated system is presented. Numerical results will show that power optimization can increase the capacity and decrease the total transmission power. By incorporating diversity and hybrid ARQ along with appropriate code ratesin the optimal power controlled system, dramatic increase in system capacitycan also be achieved.     

Performance evaluation of uplink power control algorithm over TDMA systems

Future PCS (personal communication system) cellular networks will mainly be driven by high link quality, high bandwidth utilization, low power consumption and efficient network management. Power control is one of the several major techniques which could help to achieve these goals. By exploiting power control techniques, co-channel interference could be reduced and as many links as possible could be obtained with satisfactory link quality. SIR-based (signal-to-interference ratio-based) power control was proposed as a technique for managing co-channel interference in cellular radio systems. Furthermore, new distributed autonomous feedback power control methods were introduced to achieve excellent performance without the difficult centralized control used in SIR-based methods. Unfortunately, the implementation of those power control algorithms is still challenging owing to the precision of SIR. The main aim of this paper is to investigate an uplink power control algorithm which depends indirectly on the signal-to-noise ratio in the TDMA (time division multiple access) cellular system. Simulation of the prototype hardware implementation of the receiver baseband signal processing based on the PACS (personal access communications system) specification is used as the main approach to explore the performance evaluation of this power control technique. According to simulation results, suitable values of those parameters used in this power control algorithm are derived, and the minimum frequency reuse factor under different propagation environments is also obtained for PACS under power control. © 1998 John Wiley & Sons, Ltd.     

Performance of wireless CDMA with M-ary orthogonal modulation andcell site antenna arrays

An antenna array-based base station receiver structure for wireless direct-sequence code-division multiple-access (DS/CDMA) with M-ary orthogonal modulation is proposed. The base station uses an antenna array beamformer-RAKE structure with noncoherent equal gain combining. The receiver consists of a “front end” beamsteering processor feeding a conventional noncoherent RAKE combiner. The performance of the proposed receiver with closed loop power control in multipath fading channels is evaluated. Expressions for the system uncoded bit-error probability (BEP) as a function of the number of users, number of antennas, and the angle spread are derived for different power control scenarios. The system capacity in terms of number of users that can be supported for a given uncoded BEP is also evaluated. Analysis results show a performance improvement in terms of the system capacity due to the use of antenna arrays and the associated signal processing at the base station. In particular, analysis results show an increase in system capacity that is proportional to the number of antennas. They also show an additional performance improvement due to space diversity gain provided by the array for nonzero angle spreads     

Transmission management in the deregulated environment

Three very different methods of accomplishing the same task-managing the operation of the transmission system in the deregulated power system operating environment-have been implemented as deregulated market structures have been created around the world. They are first, the optimal power flow (OPF) model found in various implementations in the United Kingdom, parts of the United States, and in Australia and New Zealand. Second, the point tariff, price area congestion control model used in the Nordpool market area in Norway and Sweden. Third, the US transaction-based model. All are pragmatic solutions implemented in advance of complete theoretical understanding. Each has strengths and flaws, and there are some surprising inter-relationships. Each maintains power system security but differs in its impact on the economics of the energy market. No clearly superior method has so far emerged. In the future, methods of combining decentralized market solutions with operational use of optimal power flow may provide better solutions to existing and emerging problems