一种改进的变步长电导增量光伏电源MPPT控制方法

光伏系统的最大功率点跟踪方法可以最大限度地利用光伏电池所能产生的电能,因此成为提高光伏发电系统运行效率、降低光伏电能成本的研究热点。针对目前常用的扰动观察法速度较慢、电导增量法在最大功率点附近有较大振荡的问题,提出一种改进变步长电导增量的最大功率点跟踪控制方法,该方法既具有电导增量法快速跟踪的优点,又能准确、稳定地跟踪到最大功率点,因此更适于提高光伏电源的能源利用率。对所提方法进行了仿真分析,并比较了几种MPPT算法的跟踪效果,结果表明,所提方法具有快速性、稳定性和有效性。     

风光储直流微电网的双输入MPPT控制策略分析

针对以输出功率为判断标准的传统的单输入扰动观察法(下文简称为“传统扰动观察法”)存在的弊端,提出一种可用于风光储直流微电网的双输入变步长扰动观察法(下文简称为“双输入MPPT控制策略”),并对风电机组和光伏发电系统分别采用两种控制策略时的占空比、发电效率等进行了对比分析。分析结果显示：相较于传统扰动观察法,风电机组采用双输入MPPT控制策略追踪最大功率点后,扰动步长减小90%的同时追踪时间减少了72.3%;光伏发电系统采用双输入MPPT控制策略追踪最大功率点后,扰动步长减小90%的同时追踪时间减少了39%。仿真结果验证了双输入MPPT控制策略的有效性,该策略适用于电感参与调压的多种场景。     

独立式风光储系统联合控制策略

针对远离大电网偏远地区采取分布式能源发电的低稳定性和低效率等问题,提出了风光储独立系统的联合控制策略,该策略结合系统功率平衡和蓄电池充放电状态设计工作模式转化控制器进行联合控制.风力和光伏系统的最大功率点跟踪控制(MPPT)采用改进传统变步长扰动观测算法(P&O);负载功率跟踪控制(LPTC)基于功率平衡梯度电压迭代法...     

基于IFOINC算法的光伏系统MPPT研究

针对光伏系统传统的最大功率点跟踪(MPPT)算法跟踪速度慢、易振荡、跟踪精度低等不足,提出一种改进的分数阶电导增量(IFOINC)算法,即将基于功率预测的变步长扰动观察(PO)算法和分数阶电导增量(FOINC)算法结合使用。IFOINC算法具体跟踪过程,先采用基于功率预测的变步长PO算法快速跟踪到MPP附近,再采用FOINC算法进一步搜索MPP从而完成整个跟踪过程。文章研究了光伏系统结构,光伏电池的等效模型,设计了IFOINC算法,建立了光伏系统MPPT仿真模型,在Matlab/Simulink下进行仿真。在光照均匀的条件下,改变其它环境条件,研究IFOINC算法的MPP跟踪效果与基于功率预测的变步长PO算法和FOINC算法之间的差异。研究结果表明,IFOINC算法的跟踪速度比FOINC算法提高了42.3%,IFOINC算法的跟踪精度比基于功率预测的变步长PO算法提高了3.9%,且消除了跟踪过程的振荡。     

光伏发电MPPT的变论域自适应模糊控制

针对常规模糊控制器在光伏发电最大功率点跟踪(MPPT)控制中存在的功率波动、控制精度低和自适应性较差等问题,提出了一种基于变论域自适应模糊控制器的光伏发电MPPT控制,该控制器能根据光伏发电输出功率偏差的变化自动调整变量的论域,从而快速准确地跟踪光伏发电系统的最大功率点(MPP)。实验结果验证了该控制方法能有效实现光伏发电MPPT控制,提高了系统的效率和稳定性。     

一种光伏MPPT模糊控制算法研究

针对太阳能光伏阵列的工作特性,在现有最大功率跟踪控制方法的基础上,提出了一种光伏MPPT的模糊控制算法——变步长扰动观察法.从偏差和偏差变化率的角度,将寻优分为二个阶段(第一阶段应用扰动观察法并设置较大步长快速接近最大功率点附近,第二阶段采用变步长的方法向最大功率点进一步逼近并至最佳),实现了光伏系统快速和高精度的跟踪要求.系统中引入了工作状态的判断环节,可以根据环境的变化,做出相应反应,提高了系统的快速跟踪性能和稳定性.     

光伏电池最大功率点跟踪控制方法的对比研究及改进

光伏发电系统中光伏电池的输出特性具有唯一的最大功率点(MPP),需要对光伏电池的最大功率点进行跟踪(MPPT)。文中分析了几种常见的最大功率点跟踪控制方法对比分析了它们的优缺点。针对MPPT控制方法中存在的启动特性较差、跟踪过程不稳定、精度不高等特点,采用一种改进爬山法,该法以恒定电压法作为启动特性及采用变步长进行跟踪控制,并利用Matlab/Simulink搭建了改进爬山法的MPPT控制模型,仿真结果验证该方法的有效性。     

一种基于变步长电导增量法的自适应MPPT控制策略

光伏电池是太阳能光伏发电系统的基本组件,其输出特性易受到工作环境的制约,基于此利用优化的最大功率点跟踪(MPPT)策略能够可以有效地提高光伏发电系统的发电效率。文章针对传统电导增量法的实时性和容错性缺陷,提出了一种基于变步长电导增量法的自适应MPPT控制算法,该算法引入了一套全新的步长调节方法,能够根据外界环境的变化实时调整扰动步长,在一定程度上解决了辐照强度剧烈变化情况下传统电导增量法动态响应速度慢且容易发生误判的问题。文章通过仿真实验验证了所提算法的有效性和合理性。     

一种光伏发电系统的双扰动MPPT方法研究

针对一种开关电容(SC)的电路结构,在此基础上提出一种双扰动观察(PO)算法,形成双向互补控制的最大功率点跟踪(MPPT),通过不同收敛域的双扰动同时提高静态稳定特性和动态响应特性,其互补控制实现死区的自返回,利用Matlab仿真软件构建基于开关电容变换器的MPPT算法模型,模拟任意参数的光伏阵列,动态跟踪光照强度和环境温度的变化,通过光伏发电平台对该开关电容变换器的MPPT控制策略进行实验验证。仿真和实验结果表明:该方法能在一定范围内对太阳电池输出功率进行跟踪调节,可快速稳定地启动并减少误判,有效降低系统输出功率在最大功率点处的振荡现象,减小光伏组件的能量损耗。     

基于不完全微分的自适应步长扰动观察法MPPT 控制

在扰动步长判断条件中引入不完全微分,与微分结合,有效减小传统扰动观察法扰动步长判断函数中完全微分带来的高频(突变)干扰,基于不完全微分实现步长自适应调整,提出基于不完全微分的MPPT控制算法。在Matlab/Simulink环境下的仿真与实验平台上所得实验结果表明,所提出算法能在不影响光伏系统最大功率跟踪速度的前提下,有效减小最大功率点附近的功率振荡,提高MPPT控制的跟踪精度。     

改进功率预测变步长扰动法在光伏MPPT中的研究

针对最大功率点跟踪技术在光伏发电系统中的应用和研究现状,提出一种改进功率预测变步长扰动法.首先分析光照强度在一个采样周期内非线性变化时功率预测法会因功率预估值偏差较大而产生误判这一现象,为减少功率振荡损失,基于牛顿插值法建立三点采样函数模型以减少预测功率值与实际功率值的偏差.其次在确定变步长的过程中纳入光照强度变化这一...     

基于电压预估法的光伏发电系统MPPT算法

光伏发电系统处于复杂光照条件下时,光伏电池阵列的输出特性呈多峰现象,致使传统的MPPT算法追踪结果可能停留在次优点。针对此问题,提出一种基于电压预估法的光伏发电系统MPPT算法,采用DMPPT电路结构的光伏阵列,通过研究其输出特性,得到复杂光照条件下光伏阵列最大功率点对应的工作电压最佳区域,并以该预估到的电压值为基础,设计了一种新型的MPPT控制算法。仿真结果表明,所提算法能有效避免光伏系统工作在次优点,提高了光伏发电的出力。     

Brushless DC motor drives supplied by PV power system based on Z-source inverter and FL-IC MPPT controller

This paper discusses operation performance of a water pumping system consist of a brushless dc (BLDC) motor coupled a centrifugal pump and accompanying a Z-source inverter (ZSI) fed by a photovoltaic (PV) array, to be improved. Despite conventional double-stage power converters, this paper proposes utilizing a single-stage ZSI to extract the maximum power of the PV array and supply the BLDC motor simultaneously. Utilizing the ZSI provides some inherent advantages such as high efficiency and low cost, which is very promising for PV systems due to its novel voltage buck/boost capability. In addition, in order to precisely perform the maximum power point tracking (MPPT) of the PV array the fuzzy logic-incremental conductance (FL-IC) MPPT scheme is proposed. The proposed FL-IC MPPT scheme provides enough modification to the conventional IC method to enjoy an appropriate variable step size MPPT control signal for the ZSI. Moreover, direct torque control (DTC) is found more effective in comparison with hysteresis current control with current shaping to drive the BLDC motor, because it benefits from faster torque response, reduced torque ripple, less sensitivity to parameters variations, and simple implementation. In the mean time, due to the frequently variations of the PV power generation; delivered mechanical power to the centrifugal pump is variable. Thus, the BLDC motor should be driven with variable reference speed. In order to improve the speed transient response of the BLDC motor and enhance the energy saving aspect of the system, it should enjoy a high quality dynamic response characteristic. Therefore, to realize these purposes, particle swarm optimization (PSO) has been proposed to regulate the proportional-integral-derivative (PID) parameters of the BLDC motor speed controller. The system configuration, operation principle and control methods are presented in detail. Finally, the proposed system was simulated in different operation conditions of the PV array by computer simulations and the effectiveness of the proposed control strategies has been validated by comparative studies and simulation results.     

基于模糊自适应PI控制的光伏发电MPPT

介绍了光伏发电过程中最大功率点跟踪(MPPT)原理,并简要分析了常规控制算法在最大功率跟踪控制中的优缺点,提出将模糊自适应PI控制算法应用到光伏系统最大功率点跟踪的控制中,该控制方法能快速响应外界环境的变化,获得系统最大功率点,且可以有效消除系统在最大功率点附近的振荡现象,提高系统的稳定性。仿真结果表明,该方法能使系统稳定地工作在最大功率点,并且控制精度高,能灵敏反应外界环境的变化。     

A novel two-mode MPPT control algorithm based on comparative study of existing algorithms

In this paper, the effectiveness of these three different control algorithms is thoroughly investigated via simulation and a proposed efficiency evaluation method of experimentation. Both the steady-state and transient characteristics of each control algorithms along with its measured efficiency are analyzed. Finally, a novel two-mode maximum power point tracking (MPPT) control algorithm combining the modified constant voltage control and IncCond method is proposed to improve the efficiency of the 3 kW PV power generation system at different insolation conditions. Finally, a novel two-mode MPPT control algorithm combining the modified constant voltage control and IncCond method is proposed to improve the efficiency of the 3 kW PV power generation system at different insolation conditions. Experimental results show that the proposed two-mode MPPT control provides excellent performance at less than 30% insolation intensity, covering the whole insolation area without additional hardware circuitry.     

Power quality improvement of solar photovoltaic transformer-less grid-connected system with maximum power point tracking control

This paper presents a transformer-less single-stage grid-connected solar photovoltaic (PV) system with active reactive power control. In the absence of active input power, grid-tied voltage source converter (VSC) is operated in the reactive power generation mode, which powers control circuitry and maintains regulated DC voltage. Control scheme has been implemented so that the grid-connected converter continuously serves local load. A data-based maximum power point tracking (MPPT) has been implemented at maximum power which performs power quality control by reducing total harmonic distortion (THD) in grid-injected current under varying environmental conditions. Standards (IEEE-519/1547) stipulates that current with THD greater than 5% cannot be injected into the grid by any distributed generation (DG) source. MPPT tracks actual variable DC link voltage while deriving maximum power from PV array and maintains DC link voltage constant by changing the converter modulation index. Simulation results with the PV model and MPPT technique validations demonstrate effectiveness of the proposed system.     

ΔD法实现光伏系统最大功率点跟踪

在光伏系统中,光照强度、环境温度和负载变化等将会影响光伏系统的功率输出,因此光伏系统最大功率点跟踪(MPPT)是光伏系统研究的一个重要环节。文章在对比当前几种MPPT算法的基础上,通过改进扰动观察法得到了一种改变变换器开关频率占空比(D)来获得光伏系统最大输出功率的方案。利用MATLAB对光伏系统进行了不同工作条件下的仿真,证明其是可行的。同时,在一个实际光伏应用系统中进行占空比微增(ΔD)法最大功率点跟踪的应用试验。     

Maximum power extraction from photo-voltaic power generator with adaptive MPP tracker

Power generation with the help of Photovoltaic (PV) arrays is emphasized increasingly and regarded as an important resource of power energy in the coming years. As the power supplied by PV arrays depends upon the insolation, temperature and array voltage, it is necessary to control the operating point to extract the maximum power from the PV arrays. A number of methods for Maximum Power Point Tracking (MPPT) has been reported in the literature. This paper discusses an adaptive method as well as compares with the conventional fixed step size method, effectively improves the MPPT speed and accuracy simultaneously. An adaptive algorithm and two phase dc-dc Converter is exercised as a MPP tracker. Ripple reduction is possible at input and output side of the converter. Mathematical models of converter are developed using state space averaging technique. The tracking responses of the system operating at the solar array MPP are evaluated. A theoretical analysis of the new algorithm in connection with dc-dc converter is provided and its feasibility is also verified by simulation results.