Robust Model-Following Control of Parallel UPS Single-Phase Inverters

This paper presents a robust control technique applied to modular uninterruptible power-supply (UPS) inverters operating in parallel. When compared to conventional proportional–integral (PI) control, the proposed technique improves the response of the output voltage to load steps and to high distorted output currents, reducing the distortion of the output voltage. Furthermore, an excellent distribution of currents between modules is achieved, resulting in fine power equalization between the inverters on stream. The crossover frequency of the different loop gains involved is moderate, so that robustness to variations of the operation point and to modeling uncertainties is achieved. A comparative study with a two-loop conventional PI control scheme is presented. Experimental results on a 1-kVA modular online UPS system confirm the viability of the proposed scheme.      

单相UPS逆变控制技术研究

为了进一步提高UPS(Uninterrupted Power Supply)输出的动态和稳态性能，介绍了一种采用电流环做内环的双环控制技术，实现了对负载电流扰动的解耦。同时为了补偿输入电压的不稳定，采用输入电压前馈控制。文中就提到的控制方法分别进行了时域和频域仿真分析，并以DSP(TMS320LF2407)为控制芯片进行了实验验证，结果显示逆变器输出电压在恶劣的负载条件下波形畸变很小。     

A Three-Level Hysteresis Function Approach to the Sliding-Mode Control of Single-Phase UPS Inverters

A new approach to the sliding-mode control ofsingle-phase uninterruptible-power-supply inverters is introduced in continuous time. A three-level hysteresis sliding function is used to directly control the inverter switches, with the result that a transistor is switched during a half-cycle while it remains either on or off during the other cycle. An expression is derived for the predicted switching frequency. The performance of the proposed control method has been tested through computer simulations and experiments under different loads (a resistive load and a diode bridge rectifier load). Simulation and experimental results verify the correct operation of the proposed control strategy. In addition, the switching frequency prediction is seen to be quite accurate.      

基于DSP控制的在线式UPS装置研究

介绍了一种基于Ti（Texas Instruments）公司的TMS320F240数字信号处理器的在线式UPS，分析了系统设计中的一些关键技术问题。设计了一台容量为6kW的在线式UPS试验装置，并进行了验证，实践证明所研制的装置完全达到技术要求。     

Comparison of Three Single-Phase PLL Algorithms for UPS Applications

In this paper, the performance assessment of three software single-phase phase-locked loop (PLL) algorithms is carried out by means of dynamic analysis and experimental results. Several line disturbances such as phase-angle jump, voltage sag, frequency step, and harmonics are generated by a DSP together with a D/A converter and applied to each PLL. The actual minus the estimated phase-angle values are displayed, providing a refined method for performance evaluation and comparison. Guidelines for parameters adjustments are also presented. In addition, practical implementation issues such as computational delay effects, ride-through, and computational load are addressed. The developed models proved to accurately represent the PLLs under real test conditions.      

广播电视播控中心UPS系统可靠性提升与实现

广东广播电视台通过采用串联热备份方式对单机UPS系统增加冗余提高可靠性,在系统设置和现场测试通过后,热备份UPS顺利地接入在线运行的配电系统,并且提供扩建的缩编、上载机房的负荷用电,克服串联热备份UPS空载运行导致电池组无法放电影响寿命的缺点,最终,不仅实现了播出配电系统可靠性升级,也充分发挥了热备份UPS的用途。     

从UPS电路拓扑看在线式UPS的性能优势

本文介绍分析了后备式、在线互动式和在线双变换式等各类UPS电路拓扑与性能，指出在线或UPS性能优势所在。     

DSP控制单相UPS并联直流环流分析与解决

在单相UPS的并联运行中,为了系统的稳定运行,必须对逆变输出进行均流控制。而逆变输出并联间的环流分为交流环流和直流环流。文中详细地分析了直流环流对系统的影响并对直流环流的改善提供了一种有效的解决方法。     

一种新的不间断电源技术的控制与性能

本文一方面说明了在通用电力公司（AEG）产品Protect 2中使用的一种新型无变压器不间断电源（UPS）的特性，另一方面，说明了它是如何通过基于16位和32位的处理器的灵活的计算机控制方法、复杂的FPGA和分布式的测量结构来实现的。     

基于PIC的后备式UPS的实现

介绍了PIC16C73B单片机和它的特点。分析了后备式UPS的基本原理。并结合PIC16C73B给出了一种后备式UPS实现的实例。文章对后备式UPS设计中的关键参数及其处理方法进行了详细介绍。并且根据硬件设计框图,具体分析了后备式UPS的逆变过程和相关的软件编程。     

大功率单相完全有源功率因数校正器的实现

首先基于现有的、典型的模拟PFC控制芯片,较为详细地描述了单级升压变换的单相AC—DC变换器领域几种基本的有源功率因数校正技术,其中包括传统有源PFC技术、跟随有源PFC技术和单周期有源PFG技术。最后基于PFC控制芯片L4981B详细地介绍了支持较大功率输出的有源PFC电路设计过程,并给出部分实验结果。     

Nonlinear Current Control of Single-Phase PFC Converters

A set of new nonlinear current control methods are presented for single-phase power factor corrected ac-dc converters. These control methods combine input current feedforward with partial feedback based on the switch current to achieve sinusoidal input current and unity input power factor. They overcome the limitations of conventional linear (average) current control in terms of control bandwidth and sensitivity to noise, resulting in high-performance input current control which can meet the most stringent harmonic current limits required by variable-frequency airborne power systems. The control methods are also ideally suited for integrated mixed-signal implementation, requiring an analog current controller which is very simple, much less sensitive to noise than conventional linear feedback control, and independent of converter and control design parameters; and a digital controller which operates with a sampling frequency much lower than the switching frequency. Detailed development of the control methods is presented along with their stability analysis and circuit implementation. A prototype converter and its operation are also presented to validate the analysis and to demonstrate the performance of the control methods.     

电台总控系统在线搬迁工程实施

本文主要介绍安徽人民广播电台总控系统在线搬迁的实施,在没有增加播出设备的情况下,对总控系统进行了结构优化和设备整合,设计了在不中断广播节目播出的情况下总控系统在线搬迁.     

UPS接口转换卡的设计与实现

针对目前大多数UPS监控系统因采用串行接口监控方式,而导致的传输距离受限制,不能实现任意距离的分散式远程监控的问题,提出了一种基于SNMP网络管理协议的UPS监控系统的设计方案,设计了集成SNMP协议的硬件接口转换卡。采用了带有SNMP协议的μC linux操作系统,完成了串行接口到网络接口的数据转换,实现了在SNMP协议下的UPS网络管理和监控。     

Sliding-Mode Control for a Single-Phase AC/AC Quantum Resonant Converter

This paper presents a sliding-mode control for a single-phase ac/ac quantum resonant converter. The closed-loop system improves regulation, sensitivity to disturbances, and transient response. The design of the closed-loop system is based on the sliding-mode control theory, and it is carried out with the help of an averaged large-signal model of the resonant converter. Simulation and experimental results are reported to validate the theoretical predictions. Essentially, the contribution of this paper is as follows: 1) the averaged large-signal model for the resonant converter; 2) the sliding-mode control scheme; and 3) the design guidelines for the control gains and parameters.      

Efficiency Optimization Control of Single-Phase Induction Motor Drives

The recent rising of oil prices and global warming crises increasingly support the ongoing practice of loss minimization control of electric motors including single-phase induction ones as the most used motors. Therefore, the tendency toward using variable-speed drives (VSDs) to save energy by adjusting motor speed is seen, but on account of increasing motor loss in nonrated conditions, an efficiency control system can improve energy saving even more. In this paper, after carrying out a detailed motor efficiency analysis, an appropriate method for motor efficiency maximization control, combined with a VSD, is presented and implemented. Experimental results of the implemented system validate the proposed method.     

Feedback Linearization of a Single-Phase Active Power Filter via Sliding Mode Control

The aim of this work is the application of the feedback linearization theory to a single-phase shunt active power filter, since this technique has been successfully applied to other areas of power electronic. The active filter is linearized by means of a nonlinear transformation of the system model, deduced from the application of Tellegen's theorem to the system. After that, a sliding mode controller is proposed to impose a desired dynamic behavior on the system, giving robustness and insensitivity to parameter variations. Moreover, the proposed controller ensures proper tracking of the reference signals and simplifies the overall control design. The controller was implemented into a low cost DSP. Experimental and simulation results are provided.     

一种实用元搜索引擎的设计与实现

元搜索引擎结果集成算法的性能直接影响元搜索引擎的查询精度和用户的满意度.文中在分析常用的结果集成算法的基础上,提出了一种改进的结果处理算法来提高查询精度,并设计了元搜索引擎系统.实验表明,该系统可以有效提高信息检索的精度.     

Control of a Single-Phase Cascaded H-Bridge Multilevel Inverter for Grid-Connected Photovoltaic Systems

This paper presents a single-phase cascaded H-bridge converter for a grid-connected photovoltaic (PV) application. The multilevel topology consists of several H-bridge cells connected in series, each one connected to a string of PV modules. The adopted control scheme permits the independent control of each dc-link voltage, enabling, in this way, the tracking of the maximum power point for each string of PV panels. Additionally, low-ripple sinusoidal-current waveforms are generated with almost unity power factor. The topology offers other advantages such as the operation at lower switching frequency or lower current ripple compared to standard two-level topologies. Simulation and experimental results are presented for different operating conditions.     

通信机房UPS带载能力及负荷率控制

本文通过对通信机房UPS设备的带载能力分析,根据现通信机房UPS的实际使用情况,在保证安全运行的基础,对UPS负荷率的控制提出相关建议.