一种基于有源滤波与光伏发电的并网逆变器控制方法

文中提出了一种基于有源滤波与光伏发电的并网逆变器的控制方法,在并联型有源电力滤波器的基础上拓展了新能源发电功能,采用电压电流双环对并网逆变直流侧电压和系统电网输出有功电流进行控制。该并网逆变器既可以滤除负载的谐波和补偿负载的无功功率,也可以实现有功功率的有效传输,适于未来微电网中并网逆变器的应用研究。     

基于超级电容的静止无功补偿器的研究，

为了实现在配电网骤降时同时补偿有功能和无功功率的目的,采用Buck／Boost型双向直流变换器连接超级电容储能装置与静止无功补偿器这一结构的电压一电流双闭环PI控制方法,通过Matlab／Simulink软件,做了相关仿真实验,得到了超级电容无论吸收功率,还是释放功率,其直流母线侧电压均恒定的结果,整个装置具有既能补偿无功功率损失又能补偿有功功率损失的特点。     

高压级联SVG电流PR控制策略

对SVG在出现无功阶跃扰动时的补偿控制进行深入研究。SVG在无功功率调节时,如果出现阶跃扰动,无功功率的调节会直接影响有功功率的调节,这是因为传统的旋转坐标系控制方法对于有功功率和无功功率的控制环路之间存在耦合关系。为此,文中引入了有功和无功的解耦控制。另外,无功的阶跃信号会引起直流母线电压的突变,故将直流分量引入装置侧输出电流的值,并将这个直流分量滤除,保证控制的稳定性。最后在仿真的基础上,以光伏电站为背景对所提方法进行现场验证,结果充分证明了该算法的有效性。     

基于功率均分的逆变器并联控制技术

本文介绍了一种基于功率均分控制的无主从独立结构的逆变器并联控制系统。分析了逆变器无功功率与电压幅值、有功功率与电压相位之间的关系，提出了并联控制方案．成功实现了5台3kVA逆变器的并联均流控制。     

含多分布式能源的微电网孤岛无缝切换策略

针对微电网并网运行切换至计划孤岛运行时负荷侧暂态振荡,提出一种孤岛无缝切换策略,有效降低负荷侧电压与频率振荡幅度。含多分布式能源的微电网孤岛运行时采用主从控制结构,主逆变器从P-Q控制切换至V-f控制,用于稳定负荷侧电压与频率。从逆变器采用P-Q控制,稳定系统内有功功率平衡。孤岛切换时,主逆变器采用状态跟踪控制,削弱因逆变器控制策略切换导致的输出不稳定性。基于PSCAD的仿真实验表明,该控制策略可有效降低孤岛切换瞬间负荷侧的电压与频率振荡,提高微电网供电稳定性。     

光伏组网单元直流侧蓄电池储能系统研究

采用了双向半桥Dc/Dc对光伏组网单元直流侧蓄电池进行充放电控制;简单说明了VSI逆变器的结构和原理:分析了双向DC/DC变换器电感电容的选取方法。通过搭建以蓄电池储能为核心的仿真模块,采用功率外环电流内环、电压外环电流内环这两种控制方式,分别在光照强度变化不大以及光照有大幅度跌落这两种情况下进行了仿真分析。仿真结果验证了这两种控制方法在稳定逆变器输出以及直流母线电压的有效性,也体现了功率外环电流内环控制的优越。     

交错并联式并网MATLAB仿真系统研究

对于小型光伏并网发电系统,文中详细分析交错两级式并网系统。直流侧为双重的BOOST升压电路实现最大功率控制,采用扰动观察法实现最大功率点跟踪,并网逆变器的控制策略电压外环电流内环的双环控制,其中电流内环为滞环控制方式,并网逆变器的输出电流跟踪电网电压,实现功率因数为1的并网方式。文中给出了基于MATLAB的系统仿真模型,结果表明光伏电池能较好地实现最大功率点跟踪,电感容量减小,并且逆变后成功并网。     

大城市电网链式STATCOM关键技术研究

文章介绍了链式STATCOM的拓扑结构,在此基础上建立了数学模型。直流侧电容电压平衡控制是链式STATCOM的一个关键技术问题,针对此问题,采用了一种分级协调控制策略,通过改变H桥单元的输出电压和电流的夹角从而调整吸收／释放的有功功率,最终控制直流侧电容电压平衡。最后,搭建了仿真模型,仿真结果验证了控制策略的正确性和可...     

光伏并网逆变器的仿真研究

为了提高光伏发电效率和电能质量,对光伏并网逆变器进行了相关研究,针对光伏最大功率点跟踪问题,对传统的电导增量法进行融合和改进．提出一种改进的电导增量控制算法。该控制算法能够快速精准地跟踪最大功率点;有效改善系统在最大功率点附近的震荡现象;提高了光伏电池的发电效率。在逆变控制方面,采用电压外环、电流内环的双PI环控制,电压外环实现中间直流母线电压的稳定控制。电流内环用于控制输出电流的稳定,两者通过中间直流母线耦合,匹配简单,系统控制具有较好的快速性和稳定性;减少了谐波含量,输出电流具有良好的正弦度,且与电网电压同频同相．因而提高了电能质量。最后用matlab对光伏并网逆变器进行建模仿真,实验结果表明该系统工作稳定．性能良好。达到了预定的设计效果。     

光伏阵列三相并网仿真模型

根据光伏太阳池板的内部结构和输出伏安特性建立光伏阵列的Matlab仿真模型,采用增量电导法跟踪光伏阵列的最大功率,利用三相电压型PWM整流器结构并网逆变器,对直流侧电压和交流侧电流实行双闭环控制,该模型可用于先伏发电系统的动态仿真研究.仿真实验证明直流侧的输出电压在给定值600 V附近波动,而交流侧的电流成正弦且谐波小.在此控制策略下光伏阵列的功率稳定,能够很好的跟随太阳辐射强度和环境温度的变化.     

适用于弱互联电网的光伏逆变器LVRT控制策略研究

目前,光伏装机在电网中占比越来越高,并网光伏逆变器也有严格的低电压穿越要求。现行低电压穿越标准要求逆变器在低电压穿越期间按照曲线给予电网足够的无功电流支撑,但是没有对期间的有功电流响应做出明确要求。弱互联区域电网稳定不仅和无功电流相关,也在很大程度上和有功电流相关,同时低电压穿越期间有功缺额对频率也有较大影响。文章分析了电网电压不平衡时锁相环控制方法,并提出了一种基于解耦双同步坐标系锁相环的低电压穿越期间有功电流无功电流协调控制策略,搭建了基于F28335+CPLD的硬件控制平台,并最终在硬件在环仿真平台中验证了控制策略的有效性。     

Parallel processing inverter system

A novel method of instantaneous voltage and power balance control of a parallel processing inverter system is proposed. It consists of a high-speed switching PWM (pulsewidth modulated) inverter with an instantaneous current minor loop controller, a voltage major loop controller, and a power balance controller. This system realizes the following functions with only one inverter: constant AC output voltage control with reactive power control, active filtering to absorb load current harmonics, DC voltage and current control as AC-to-DC converter, and uninterruptible power supply (UPS) for stand-alone operation. This system covers a wide application range, including UPS systems, new energy systems, and active filters with voltage control functions     

DC voltage control and stability analysis of PWM-voltage-typereversible rectifiers

A PWM voltage rectifier has useful characteristics on its DC and AC sides. On its DC side, a DC-link unidirectional voltage is obtained and bidirectional power transfer capability is possible by reversing the flow direction of the DC-link current. On its AC side, near sinusoidal current waveforms and AC four-quadrant operation can be obtained, leading to high-quality power being exchanged between the power converter and the mains. The use of AC filters becomes unnecessary. The rectifier DC voltage must be regulated to a constant value. In this paper, three solutions for the DC voltage control are presented. In the first solution, the DC voltage is controlled by acting upon the quadrature component of the power converter fundamental Park's voltages with relation to the mains voltages. Slow responses are necessary because of stability reasons. Also, load power variations produce both active and reactive power variations in the power converter AC side. To improve the DC voltage response, a second control solution is presented. The power converter currents in Park's coordinates must be controlled. The DC voltage is controlled by controlling the direct Park's current component and, thus, acting only on the active power of the converter AC side. Faster responses are achieved. In this case, load power variations do not produce reactive power variations in the converter AC side. The third control solution is a simplified version of this last one. Experimental results from a 2 kVA IGBT-based prototype showing good system dynamic performance are presented     

基于DSP的并网逆变器的设计

逆变是整流的逆过程,逆变器是将低压直流电转换成交流电的装置。为了能将转换后的交流电送回电网,实现能量再循环,设计了基于DSP的并网逆变器,采用倍频单极性SPWM技术实现逆变控制,并利用DSP外设CAP检测逆变器输出电流频率和相位,以软锁相技术实现逆变器输出电流的相位和频率与电网电压同步;利用DSP外设ADC采集逆变器的输出电流与电网的电压,采用PI闭环调节以增加逆变器输出电流的稳定性,最后搭建实验样机验证设计的可行性。     

Implementation of a Three-Phase Capacitor-Clamped Active Power Filter Under Unbalanced Condition

A capacitor-clamped voltage-source inverter for active power filter operation under balanced and unbalanced conditions is proposed to suppress current harmonics and compensate the reactive power generated from the nonlinear loads. The adopted voltage-source inverter is based on a three-level capacitor-clamped topology to reduce the voltage stress of power semiconductors. Two control loops are used in the control scheme to achieve harmonic and reactive currents compensation and to regulate the inverter dc side voltage. In the adopted inverter, the neutral point voltage is compensated by a voltage compensator to obtain the balanced capacitor voltages on the dc side. In order to control the flying capacitor voltages, two redundant states in each inverter leg can be selected to compensate the flying capacitor to obtain a better voltage waveform with low harmonic contents on the ac terminals. The balanced and sinusoidal line currents are drawn from the ac source under the balanced and unbalanced conditions. The feasibility of the proposed scheme is confirmed through experimental results     

一种单相串联混合电力有源滤波器的研究

文中对串联混合电力滤波器抑制谐波的原理进行了分析。为了检测单项系统的谐波电流,提出一种基于虚拟三相法和瞬时无功理论的谐波检测方法,并且对串联滤波逆变器的直流侧电压的控制进行了讨论。仿真结果证明了其有效性。     

新型三相三线制并联有源滤波器的滑模控制方法

为了提高有源滤波器的谐波补偿效果,设计了一种新型滑模控制器,用于三相三线制并联有源滤波器的参考电流跟踪控制.谐波电流检测方法采用基于瞬时无功功率理论的谐波电流检测方法,能快速、准确的检测出负载电流中的谐波分量.直流侧电压控制方法采用PI控制方法实现.Simulink仿真结果显示,与传统的滞环比较控制方法相比,所设计的新型滑模控制方法能够有效的降低跟踪误差,提高有源滤波器的谐波补偿效果.     

A novel DC voltage control strategy of series hybrid active power filter

In this article, a novel DC voltage control strategy which is independent of the detection of the primary winding voltage across the series transformer is proposed to solve the DC voltage control problem of the series hybrid active power filter (APF). Meanwhile, this proposed DC voltage control method adopts an open-loop control strategy. The inverter generates unchanged DC voltage control current to ensure that the fundamental voltage loss of the series transformer remain stable. The simulation and experimental results validity and feasibility of the proposed DC voltage control the method of the series hybrid APF.