Model-Based $hbox{H}_{infty}$ Control of a Unified Power Quality Conditioner

This paper presents a solution to the control of a unified power quality (PQ) conditioner (UPQC) for PQ improvement in power distribution systems. The problem formulation allows not only harmonic compensation but also voltage sags/swells, load demand changes, and power factor correction to be tackled in a unified framework. The proposed controller combines the multivariable regulator theory with $hbox{H}_{ infty}$ loop shaping, so that zero steady-state error, robustness to modeling uncertainties, and insensitivity to supply frequency variations can be accomplished simultaneously, thus providing a complete theoretical solution to all the aforementioned PQ problems. The effectiveness of the proposed controller is, in practice, verified by experimental studies on a single-phase power distribution system.      

基于MATLAB的电压闪烁下电弧炉特性仿真研究

由于非线性负载(电能电子控制设备和电弧炉等)的飞速增长,电能质量已经成为今天的电力系统工程师越来越关注的焦点。谐波和电压闪烁已经被当作是电能质量问题引入电力系统中,它们被认为是电弧炉操作的非线性反应的结果。电弧炉模型多种多样,文中提出一种在MATLAB下的电弧炉时域模型,该模型可以利用MATLAB来研究电力系统中的电弧炉性能。通过分析本文的模型,可以研究电弧炉不同操作环境下的一些特性。     

PTF-based control algorithm for three-phase interleaved inverter-based SAPF

In this paper, modelling and hardware implementation of three-phase interleaved inverter-based shunt active power filter (SAPF) is proposed to mitigate current harmonics, reactive power for ensuring unity power factor and load balancing without shoot-through effect. Shoot-through effect is one of the hazardous issues in conventional voltage source inverters such as damage of power electronic switches, electromagnetic interference, ringing in the power circuitry. The present power system has inevitable non-linear loads which create large variations in the supply voltage distortions. Therefore, the compensation capability and efficiency of the SAPFs degrades. A novel predictive tuned filter is proposed in this paper to estimate the variations in the amplitude of supply voltage, frequency and harmonics for extracting the fundamental voltage signal. The fundamental extracted signal is further processed for reference current generation using generalized p-q theory. The performance of the proposed system is simulated using MATLAB®/Simulink environment and tested under different supply voltage conditions. The simulation results have been validated by developing a prototype in the laboratory by using a dSPACE1104 controller. It is found from the simulated and experimental results that the proposed system is fast, robust and accurate which improves the power quality without shoot-through problem.     

基于LabVIEW的中频电源电能质量分析测试系统设计

为了实现对中频电源系统检测的需求,提出了一种基于LabVIEW的电能质量分析测试系统设计方案,并完成系统的软硬件设计。该系统的硬件部分主要用来采集中频电源系统的电流、电压信号处理为计算机能够识别的弱电信号,软件部分采用LabVIEW进行编程,能够完成对电流、电压信号的计算分析。实际应用表明,该系统具有操作简便、测试准确的特点,达到了对中频电源系统各电量参数进行检测和分析的设计要求。     

离子推进系统电源研究

离子推进电源处理单元（PPU）是组成离子电推进系统的关键设备之一。本文以某离子电推进系统配置的电源处理单元为例,针对多路组合、输出功率大、电压高及时序控制等电源特点,采用不同的电源变换拓扑方案,来实现复杂电源功能。并通过实际电路验证和检测,研究结果满足了设计指标要求。     

论电力系统中的谐波分析方法

随着电力、电子技术的迅猛发展,电力系统中普遍使用了各种变频设备。但是由于非线性负载与电力、电子设备超量的连入,使得谐波或间谐波被大量的混入到电力系统中。而谐波会导致电能在质量方面下降,最终会对电网或者电力设备产生严重的影响。而用电单位和用电个人对电能的质量要求也变得越来越高,如何对谐波进行有效而准确分析就成了当今电力部门研究电能质量的一个重要课题。文中对直接应用FFT的谐波分析方法进行了简单的论述。     

配电网电能质量监控系统研究

电能质量(PQ)因为不同的PQ信号产生了多种分析技术,使得整合多种电能质量监控难度较大。为了解决这个问题,利用prony的PQ分析建立电能质量监控系统,可便捷地分析和检测各类PQ干扰,如基频偏差、谐波、相间谐波、电压波动以及PQ事件。目前,该监控系统已在南方电网中实施应用。     

用于高压电力实验站的高精度光纤传输系统

本文介绍了一种用干高压电力实验站的高精度光纤传输系统。该系统作为计算机数据传输媒介，具有设计合理、结构简单、传输精度高、成本低等优点，可用于高压电力部门及其它恶劣环境下传递信号之用。     

基于VSI的电力扰动发生装置的开发

电能质量问题包含频率偏差、电压偏差、谐波、电压波动与闪变以及电压暂降与暂升等几个方面。如果在教学实践环节中,让学生自己通过实验来产生和观察这些现象,显然有助于加深学生对电能质量知识的理解和掌握。这就需要有能产生这些现象的电能质量扰动发生装置。由于目前市场中的电能质量扰动发生装置不仅售价高且不能完全满足教学要求,因此开发了一套发生装置。该装置基于电压型逆变器VSI的拓扑结构与工作原理,不仅可以实现上述电能质量现象,还可以驱动一定功率的设备,从而对于电能质量问题引起的危害也可以有实际的认识。     

A Compact Digitally Controlled Fuel Cell/Battery Hybrid Power Source

A compact digitally controlled fuel cell/battery hybrid power source is presented in this paper. The hybrid power source composed of fuel cells and batteries provides a much higher peak power than each component alone while preserving high energy density, which is important and desirable for many modern electronic devices, through an appropriately controlled dc/dc power converter that handles the power flow shared by the fuel cell and the battery. Rather than being controlled to serve only as a voltage or current regulator, the power converter is regulated to balance the power flow to satisfy the load requirements while ensuring the various limitations of electrochemical components such as battery overcharge, fuel cell current limit (FCCL), etc. Digital technology is applied in the control of power electronics due to many advantages over analog technology such as programmability, less susceptibility to environmental variations, and low parts count. The user can set the FCCL, battery current limit, and battery voltage limit in the digital controller. A control algorithm that is suitable for regulating the multiple variables in the hybrid system is described by using a state-machine-based model; the issues about embedded control implementation are addressed; and the large-signal behavior of the hybrid system is analyzed on a voltage–current plane. The hybrid power source is then tested through simulation and validated on real hardware. This paper also discusses some important issues of the hybrid power source, such as operation under complex load profiles, power enhancement, and optimization of the hybrid system. The design presented here can not only be scaled to larger or smaller power capacities for a variety of applications but also be used for many other hybrid power sources.     

大功率测控装备交流用电特性分析

针对近年来大功率卫星测控通信装备(TT&C)在供配电环节出现的各种问题,首先,阐述供配电网、用电设备为保证电能质量需要遵守的相关标准,详细分析交流供电系统瞬时功率的波动特性;然后,以某型精密跟踪脉冲雷达为例,侧重分析大功率TT&C 装备交流电能的使用方式和特性,说明各类型交流电能使用方式及耐受供电电压跌落的能力,纠正TT&C 装备必须始终保持交流供电零中断不全面认识;最后,提出大型TT&C 装备电源分系统设计阶段的基本要求和TT&C 装备交付用户时需要向供电系统提交的技术性能参数,从而确保科学合理地设计供配电系统,实现TT&C 装备的安全可靠运行。     

多电平单元串联电压源型变频器高压电源瞬时失电连续运行研究

高压变频调速系统现场应用复杂，工艺多样。在重要的大型工业系统中，高压电源系统有双备用，紧急互投等功能，当变频器对大功率的电机供电时，如果高压电源进行切换，将出现0．1S～1．5s左右的失电间隔，要求变频器在失电间隔中能正常工作，且转速波动较小，达到系统在失电期间不出现剧烈振荡。对于多电平单元串联电压源型变频器，当通过对功率单元电容值的加大，PWM输出占空比减小的方法提高失电连续运行性能，其效果均不理想。在经过大量论证后，采用特殊的DSP控制逻辑，并利用旋转系统中的飞轮动能转换，取得实现变频器在高压瞬时失电时保持稳定运行。     

基于智能整流技术的电网电流谐波补偿方法研究

目前用于电网电流谐波补偿的电器设备,主要以PWM整流器为主。基于PWM整流器的电源产品只能被动地减小自身向电网输出的谐波电流,而对电网中业已存在的电流谐波污染束手无策。为了解决电网中电流谐波污染以及相关联的电压波形失真问题,采用基于SRM(智能整流模块)技术对电网电流谐波进行补偿。仿真结果表明,基于SRM的电力电子装置在从电网吸取电流并在向负载供电的同时,还能对电网电压的波形进行补偿,使电网电压波形接近正弦波形。     

基于STM32的蓄电池电流检测系统设计

蓄电池是一种储能设备,能利用存储的电能为各种用电设备提供电源,且能循环使用.蓄电池电流检测系统采用STM32为系统控制核心,经过转换电路将电流信号转变成为电压信号,并通过AD模块对电压信号进行采样处理并输出.通过输出的电流值来判断蓄电池是否正常工作,如果低于正常值则发出报警信号.     

有源滤波器在中频电炉中的节能分析

中频电炉作为主要的加热感应设备,其产生的谐波污染对电网电能质量构成威胁。文中针对中频电炉存在的谐波问题,分析比对原有的治理措施,提出了新的谐波治理装置——中频电炉用有源电力滤波器,对其主电路结构及工作原理进行分析。并对有源滤波器在中频电炉上的节能成效进行了分析,分别从变压器、换相角、交直流电压变化等方面进行了能耗分析,最终计算出净节能达到6.2%,节能效果显著。     

Power quality, the volts and amps of electricity supply

Concerns over power quality are no longer restricted to the technical specialist. The author outlines a topic increasingly recognised as crucial to the smooth operation of modern business and manufacturing. The term power quality refers much more to the electrical parameters of the supply-the volts and amps on the system. Thus, power quality includes the frequency of the supply, its voltage level as well as the presence of waveform abnormalities such as harmonic content, flicker or voltage transients. Power factor and (voltage) balance between phases on a three-phase system may also be of interest. From an end-user perspective, it is usually the short duration voltage dips which cause the most problems when they result in the frequent maloperation of equipment. The author discusses the problems of voltage dips and solutions to the problems     

Enhanced power quality based single phase photovoltaic distributed generation system

This article presents a novel control strategy for a 1-? 2-level grid-tie photovoltaic (PV) inverter to enhance the power quality (PQ) of a PV distributed generation (PVDG) system. The objective is to obtain the maximum benefits from the grid-tie PV inverter by introducing current harmonics as well as reactive power compensation schemes in its control strategy, thereby controlling the PV inverter to achieve multiple functions in the PVDG system such as: (1) active power flow control between the PV inverter and the grid, (2) reactive power compensation, and (3) grid current harmonics compensation. A PQ enhancement controller (PQEC) has been designed to achieve the aforementioned objectives. The issue of underutilisation of the PV inverter in nighttime has also been addressed in this article and for the optimal use of the system; the PV inverter is used as a shunt active power filter in nighttime. A prototype model of the proposed system is developed in the laboratory, to validate the effectiveness of the control scheme, and is tested with the help of the dSPACE DS1104 platform.     

Unified power quality conditioner with reduced switch topology for distributed networks

A unified power quality conditioner (UPQC) is a combination of shunt and series converter used to mitigate various power quality issues. In this work the shunt and series converters are designed with reduced number of switches. The new UPQC with reduced switches is controlled using SRF based Carrier Double Zero Sequence Signal Modulation (CDZSSM) technique to mitigate the various power quality issues like voltage sag, current ripples and  Total Harmonic Distortion in voltage and current waveforms. This reduced switch UPQC with CDZSSM control inherits all the merits of the conventional UPQC system, but the proposed UPQC system has better utilization of DC link voltage and moreover the voltage stresses across the switches are reduced. The results obtained from simulation and hardware of the reduced switch UPQC are compared and presented.

     

级联式电流扰动发生装置的主电路设计

随着电力事业的发展,电能质量问题得到了越来越多的关注。为了在电能质量装置的设计实验阶段就详细分析和解决其在实际电网中可能遇到的各种问题,设计一种性能良好、可靠且功能多样化的扰动装置就成为必然的需求。文中介绍一种电压等级10 kV,容量3 MVA的电流扰动装置,主要用于模拟真实电网系统的各种电流环境。装置前端采用单位功率因数的全桥全空整流器,级联H桥拓扑用于产生所需的各种类型电流扰动源。文章着重介绍了装置各项参数的详细设计计算方法,并介绍了基于matlab/simulink的仿真结果,同时证明了文中所提出的设计方法的可行性和该装置投入使用的可行性。     

2kW有源功率因数校正电路设计

有源功率因数校正可减少用电设备对电网的谐波污染,提高电器设备输入端的功率因数。详细分析有源功率因数校正APFC(active power factor corrector)原理,采用平均电流控制模式控制原理,设计一种2 kW有源功率因数校正电路。实验结果表明:以TDA16888为核心的有源功率因数校正器能在90～270 V的宽电压输入范围内得到稳定的380 V直流电压输出,功率因数达0.99,系统性能优越。