一种基于导抗变换器理论的光伏并网逆变器的研究

详细分析了导抗变换器的基本理论,对比分析了各种用于新能源发电的高频链周波变换器的结构及控制策略,结合导抗变换器的恒流特性和高频链逆变技术,应用于光伏并网发电系统中。由于导抗变换器仅输出、输入电压成正比的电流,故输出电流不受电网电压的影响。负载电压变化时,系统无需电流负反馈环节也可实现馈入电网电流功率因数近似为1,不仅提高了系统输出电流的稳定性,降低了电流波形的谐波含量,同时也实现了装置小型化。最后,仿真结果证明了该方案的可行性。     

基于导抗变换器的ICPT恒流源补偿网络设计

针对感应耦合电能传输系统负载切换时输出电流不稳定问题,提出一种用于恒压输入、恒流输出的二次侧补偿网络。该补偿网络将松耦合变压器及补偿元件等效为导抗变换器,不仅可以实现输出电流与负载无关,而且可以保证系统处于完全谐振状态。依据互感模型,利用二端口理论建立了系统的阻抗模型,推导了输出电流与输入电压关系,给出了整个系统实现输出恒流以及单位功率因数输入的参数配置方法,并分析了主要参数对系统性能的影响。另外,对系统参数进行了优化设计,以便减小装置体积,降低成本。仿真与实验结果证明了理论分析的正确性。     

逆变器电路及其系统结构综述

随着焊接设备、太阳能和风能在生产和生活中获得了越来越广泛的应用,其关键技术(逆变技术)也得到广泛的应用,因此逆变技术在新型能源的的开发利用和焊接设备应用领域有着至关重要的地位;新型的逆变电路和先进的控制技术渗透到逆变电源系统中,使得逆变电源向高频化、低损耗和低谐波畸变率等方向发展,构成了现代逆变电源的三个关键性指标;本文系统地论述了DC-AC逆变电源技术中传统的和新型的电路拓扑,并指明了它们各自的优点,同时也详尽的论述了典型逆变电源系统结构,表明高频环节逆变技术替代低频环节逆变技术是发展的必然趋势.     

新型恒功率输出开关变换器控制策略的研究

面向高强度气体放电灯，提出一种新型恒功率输出控制策略，详细分析了它的电路组成和工作原理，并以其在单端反激式DC／DC变换器的应用为例加以实验验证。在其后级加一低频全桥开关变换器，可作为交流高强度气体放电灯的工作电源，能与高强度气体放电灯的不同阶段的不同负载特性良好匹配。     

一种用于光伏发电系统的新型高频逆变器

提出一种新型的用于光伏发电的高频逆变电路,该电路适用于小型光伏并网发电系统,由Buck-Boost变换器和电流源高频链逆变器构成。Buck-Boost变换器工作在电感电流断续模式,由它来实现光伏模块的最大功率点跟踪;高频链逆变器对Buck-Boost变换器输出的能量进行逆变,得到与电网电压同步的电流。该电路结构简单、效率高,光伏模块的最大功率点不受负载变化的影响。该方案通过了实验验证。     

Hybrid‐type immittance converter

The immittance converter has an input impedance that is proportional to the admittance of a load connected across output terminals. Therefore, in this converter, the output current is proportional to the input voltage and the input current is proportional to the output voltage. Consequently, it converts a constant‐voltage source into a constant‐current source and a constant‐current source into a constant‐voltage source. It is well know that the quarter‐wavelength transmission line shows immittance conversion characteristics. However, it has a very long line length for the switching frequency of converters and is not suitable for power electronics application. Thus, we proposed five types of immittance converters that consist of lumped elements L and C and showed improved immittance conversion characteristics at a resonant frequency. The output characteristics and efficiency characteristics of an immittance converter are the most important parameter when it is used in practical applications in a high‐frequency link. In this paper, we show voltage–current transformation characteristics, current–voltage transformation characteristics, and efficiency characteristics of a hybrid‐type immittance converter which consist of L and C elements with losses. The excellent characteristics were confirmed analytically and experimentally. © 2001 Scripta Technica, Electr Eng Jpn, 138(3): 80–86, 2002     

High-frequency power transmission and selective distribution among loads by using distributed constant lines

A widely used high-frequency induction heating system usually consists of a high-frequency power source and a load circuit to be heated. Since such a system can heat only one load circuit, heating two or more loads requires that other sytems be devised. Several problems result, including the need for many power sources, switches, and high-frequency power transmission lines. To solve these problems, the authors propose a new system that can selectively supply two induction heating circuits with high-frequency power. This system is composed of a high-frequency voltage-type inverter, a parallel resonant load circuit, and a series resonant load circuit, which are connected in series by distributed constant lines of specific length. Analysis of the operating characteristics of the system confirms that the system can supply the loads with high-frequency power selectively and efficiently, with minimum interference between loads. The authors have compared theoretical simulation waveforms with actual waveforms observed on experimental equipment with output ratings of 1 to 2 MHz and 1 kW. As a result, experimental data agree well with theoretical data. This paper describes an operating principle and operating conditions of the system, and verifies that the theory we discuss is reasonable.     

高频链结构车载逆变电源研制

车载逆变电源的需求量随着汽车工业的发展而迅速增加。由于传统的逆变器采用的是工频变压器及模拟控制,因此导致系统体积大、转换效率低、设计复杂、可靠性差。针对这些缺陷,研制了一台基于PIC16C711数字控制的具有高频链环节的3 kW方波车载逆变电源,并给出了系统设计框图及部分设计参数,该电源具有过温、过流、过压、欠压等监控电路。试验结果表明,该逆变电源输出电压稳定、体积小、可靠性高,满载效率可达90.1%。     

一种新型三相电流型逆变器的研究

提出了一种基于导抗变换器的新型三相电流型逆变器,并对其控制策略作了理论分析、仿真和实验研究.本系统利用导抗变换器的电压源-电流源变换特性,将输入直流电压变换为高频正弦电流,经高频变压器隔离及电流等级变换后进行裂相调制,输出为三相正弦电流.相比于传统的电流型逆变器,采用此方法不仅省去了直流侧电抗器,而且采用高频变压器替代了工频变压器,减小了隔离变压器及输出滤波器的体积,有利于装置的小型化和降低成本.仿真和实验结果证明了该方案的可行性及有效性.     

基于FPGA的高频链逆变器控制电路的设计

高频链技术使逆变器中变压器趋向于小型、无噪声化,但增加了控制电路的设计难度。因此,针对移相PWM控制高频链周波变换型逆变器设计了一套基于现场可编程逻辑门阵列(FieldProgrammableGateArray,FPGA)的控制电路。详细介绍了逆变器的工作原理和控制电路的设计方法,其中控制电路带有电压反馈闭环,具有故障检测保护和参数显示功能。控制波形的生成、保护电路和显示译码电路全部集成于FPGA内部,大大降低了电路复杂程度。实验结果表明,电路运行稳定,适于实际应用。     

推挽双向电流源高频环节航空静止变流器研究

提出了推挽双向电流源高频环节逆变器电路拓扑 ,分析研究了其稳态原理和电压瞬时值反馈控制方案。设计并研制的 2 5 0VA2 7VDC/ 115V4 0 0HzAC航空静止变流器原理样机 ,具有电路拓扑简洁、双向功率流、控制简单、变换效率高、可靠性高等优点 ,在低输入电压小功率逆变场合具有重要应用价值。     

A three‐phase constant‐current source using an immittance converter

The term immittance converter refers to an impedance–admittance converter. The immittance converter has an input impedance that is proportional to the admittance of the load connected across output terminals. In this converter, the output current is proportional to the input voltage and the input current is proportional to the output voltage. Consequently, it converts a constant‐voltage source into a constant‐current source and a constant‐current source into a constant‐voltage source. It is well known that the quarter wavelength transmission line shows immittance conversion characteristics. However, it has a very long line length for the switching frequency, and is not suitable for power electronics applications. We thus proposed immittance converters that consist of lumped elements L, C and show improved immittance conversion characteristics at a resonant frequency. A three‐phase constant‐current source is proposed in this paper. It is possible to realize this by a simple circuit using an immittance converter. In this paper, circuit operation, characteristic equations, and results of simulation are described. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(4): 47–54, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20078     

一种新型光伏并网逆变器控制策略

分析了导抗变换器的特性，详细推导了整个系统各点电压、电流，提出一种新颖的三角波-三角波调制方法，该控制策略克服了采用传统正弦波-三角波调制方法带来的并网电流谐波含量高、功率因数低的弊端。将导抗变换器和光伏并网逆变系统有机结合在一起，利用导抗变换器的电压源-电流源变换特性，将光伏电池阵列的直流电压变换为正弦包络线的高频电流，经过高频变压器隔离和电流等级变换，得到的高频电流再经过高频整流桥及工频逆变器逆变后并入电网，实现了电流源并网。相对传统的电流源型并网发电系统，采用该方法不仅省去了串联电感，而且用高频变压器取代了工频变压器，有利于实现装置小型化和降低成本。另外，利用电网电压过零信号控制工频逆变器，保证了并网电流和电网电压同步，进一步提高系统功率因数，实现正弦电流并网。通过实验证明了该控制策略的可行性，该方法非常适合分散式家用光伏并网发电系统。     

基于双PWM补偿型单相交流稳压电源的设计

应用PWM整流器代替二极管不可控整流,既减少对电网的谐波污染,又可以实现能量双向流动.电压电流双闭环控制保证了直流侧电压的稳定和交流侧电流对电网电压的跟踪.逆变器采用固定开关频率的直接电流控制方法中的预测电流控制,电流内环采用比例调节,提高了电流响应速度.电压外环采用电压有效值反馈的PI调节,保证对逆变器输出电压的稳定...     

三电平双降压式全桥逆变器

提出了一种新颖的三电平双降压式全桥逆变器。该逆变器是在两电平双降压半桥逆变器基础上改进得到,保留了双Buck逆变器无桥臂直通、无体二极管反向恢复问题的优点和半周期工作模式,又克服了其缺点：器件耐压要求减半,更适合高压的输出场合;其桥臂输出不再是传统半桥型逆变器的两电平双极性调制波,而是直流电压利用率高、谐波含量小的三电平单极性调制波;其输入侧不再像半桥型逆变器那样需要2个大电容进行分压。该逆变器是一种高效高可靠且体积小的性能优异的逆变器。试验验证了以上分析的正确性。     

A suitable single-phase pulse width modulation current source inverter for utility interactive photovoltaic generation system

A suitable single-phase inverter for the utility interactive photovoltaic generation system is proposed. The single-phase Pulse Width Modulation (PWM) current source inverter has a novel circuit configuration in which an auxiliary branch is added to the normal single-phase bridge circuit. To reduce the size and weight of the dc reactor, a double frequency parallel resonance circuit (LC tank circuit) is inserted in the dc side of the inverter. As a result, the double frequency voltage appearing in the dc side of the inverter due to the pulsation of the single-phase instantaneous power is perfectly suppressed by the tank circuit. The constant dc current without pulsation is supplied from PV array to the inverter. The inverter provides a sinusoidal ac current for domestic loads and the utility line with unity power factor. The virtual maximum power of the PV array can be obtained without any feedback control. In the system, the PV array can play an important role as a current-limiter due to its V-I characteristics. Computed waveforms by simulation are shown. Excellent inverter equipment will be realized that is smaller in size and lighter in weight than is usual for a conventional inverter.     

PWM开关功率变换器闭环系统数值仿真的一种方法

提出了ＰＷＭ开关功率变换器闭环系统分阶段数值仿真的一种方法。将主电路及控制电路作为一个统一的整体,建立闭环系统各子拓扑的线性状态微分方程,使各拓扑切换时刻的确定变得非常简单且提高了仿真效率。     

电力电子在城轨电动车辆中的应用与发展

对电力电子技术在城轨交通车辆中的应用及发展进行了综述,对国内进口地铁和轻轨车辆电气系统的基本结构进行了比较和评述,最后结合目前国内外的实际应用情况对电气系统提出了一些看法。     

三相高频链矩阵式逆变器的HPWM调制策略原理与实现

安全换流是制约矩阵式变换器实用化的关键问题,高频链与矩阵变换器相结合时,高频变压器环节更为换流增添了复杂因素。本文就三相高频链矩阵式逆变器的换流问题展开研究,针对电路拓扑的结构特点,运用解结耦思路以常规逆变器的角度分析和控制矩阵变换器,提出一种新型无谐振的混合脉宽调制策略,构建了核心的调制组合逻辑,详细分析了变压器高频交流周期内变换器的工作状态。运用该调制策略可以在没有任何辅助检测环节的条件下有效解决双向开关固有的换流问题,且能实现开关零电压或零电流动作。仿真和实验一致验证了所提出的调制方案和所设计的实现逻辑是可行与实用的。