太阳能电池板最大功率点跟踪技术的比较

太阳能电池板最大功率点跟踪技术的比较 IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 22, NO. 2, JUNE 2007 Comparison of Photovoltaic Array Maximum Power Point Tracking Techniques 光伏阵列最大功率点跟踪技术的比较 Trishan Esram, Student Member, IEEE, and Patrick L. Chapman, Senior Member, IEEE Abstract—The many different techniques for maximum power point tracking of photovoltaic (PV) arrays are discussed. The techniques are taken from the literature dating back to the earliest methods. It is shown that at least 19 distinct methods have been introduced in the literature, with many variations on implementation. This paper should serve as a convenient reference for future work in PV power generation. 摘要:关于光伏阵列最大功率点跟踪的许多不同技术的讨论，著作中的这些方法都可以 追溯到最早的方法。结果表明至少有19种方法已经在著作中被介绍，有许多已经实现变形。 本文应该对将来的光伏发电工作提供一个方便的参考。 Index Terms—Maximum power point tracking (M ppt 关于艾滋病ppt课件精益管理ppt下载地图下载ppt可编辑假如ppt教学课件下载triz基础知识ppt ), photovoltaic (PV). 索引词—最大功率点跟踪，光伏。 I. INTRODUCTION I(简介 TRACKING the maximum power point (MPP) of a photovoltaic (PV) array is usually an essential part of a PV system. As such, many MPP tracking (MPPT) methods have been developed and implemented. The methods vary in complexity, sensors required, convergence speed, cost, range of effectiveness, implementation hardware, popularity, and in other respects. They range from the almost obvious (but not necessarily ineffective) to the most creative (not necessarily most effective). In fact, so many methods have been developed that it has become difficult to adequately determine which method, newly proposed or existing, is most appropriate for a given PV system. 跟踪光伏阵列的最大功率点通常是光伏系统的主要部分，鉴于此许多最大功率点跟踪方 式已经被开发和实现。这些方法各不相同，如复杂程度、传感器需要、收敛速度、花费、范 围的有效性、硬件实现、普及程度以及其他方面。他们几乎涵盖了所有的从平淡无奇(但是 不一定不起作用)到最具创造性(不一定都有效)。事实上，由于许多的方式已经被开发， 在新提出的或是现存的方法中，对于给定的光伏系统准确的决定最适合方式的变的困难 Given the large number of methods for MPPT, a survey of the methods would be very beneficial to researchers and practitioners in PV systems. Fig. 1 shows the total number of MPPT papers from our bibliography per year since the earliest MPPT paper we found. The number of papers per year has grown considerably of the last decades and remains strong. However, recent papers have generally had shorter, more cursory literature reviews that largely summarize or repeat the literature reviews of previous work. This approach tends to repeat what seems to be conventional wisdom that there are only a handful of MPPT techniques, when in fact there are many. This is due to the sheer volume of MPPT literature to review, conflicting with the need for IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 22, NO. 2, JUNE 2007 brevity. 鉴于大量的方法来研究MPPT，在光伏系统中采用调查的方法对研究人员和实践者都是 非常有益的。图一给出了自从我们发现最早MPPT论文以来每年我们文献目录中MPPT论 文的总数目，最近几十年论文的数量已有了长足的发展并且发展仍然很强劲。然而，最近的 论文普遍较短，更多粗略的文学评论以致大量的总结或重复前人的总结工作。这种重复方式 似乎是传统的智慧，以至于只有很少的MPPT技术，但事实上有很多。这是由于有大量的 公开的MPPT文献回顾与简洁的需求相冲突。 This survey is a single reference of the great majority of papers and techniques presented on MPPT. We compiled over 90 papers pertaining to different MPPT methods published up to the date of submission of this manuscript. It is not our intention to establish a literal chronology of when various techniques were proposed, since the publication date is not necessarily indicative of when a method was actually conceived. As is typical of review papers, we have elected not to reference patents. Papers referencing MPPT methods from previous papers without any modification or improvement have also been omitted. It is possible that one or more papers were unintentionally omitted. We apologize if an important method or improvement was left out. 这个调查参考了绝大多数提出MPPT的论文和技术。我们收集了超过90篇关于MPPT 不同方法的论文的手稿提交的日期。我们的意图不是当不同的技术被提出时建立一个文字年 代， 因为出版日期不能表明一种方法是什么时间构思的。作为典型的评论性文章，我们推 选不涉及专利。如果论文中所涉及的MPP T的方法来自以前的论文而没有任何的修改和改 善，则论文将被忽略。一篇或更多的论文被无意识的遗漏也是可能的，如果是一种重要的方 法或改进被遗漏，我们表示歉意。 Manuscript received September 24, 2004; revised September 8, 2005. This work was supported by the National Science Foundation ECS-01-34208. Paper no. TEC-00276-2004. The authors are with the Grainger Center for Electric Machinery and Electromechanics, University of Illinois at Urbana-Champaign, Urbana, IL 61801- 2918 USA (e-mail: esram@uiuc.edu; chapman@ece.uiuc.edu). Digital Object Identifier 10.1109/TEC.2006.874230 Fig.1. Total number of MPPT papers per year, since 1968. This manuscript steps through a wide variety of methods with a brief discussion and categorization of each. We have avoided discussing slight modifications of existing methods as distinct methods. For example, a method may have been first presented in context of a boost converter, but later on shown with a boost buck converter, otherwise with minimal change. The IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 22, NO. 2, JUNE 2007 manuscript concludes with a discussion on the different methods based on their implementation, the sensors required, their ability to detect multiple local maxima, their costs, and applications they suit. A table that summarizes the major characteristics of the methods is also provided. 这份手稿通过各种各样的方式进行简要的讨论和分类，我们讨论将稍加修改已经存在的 方法作为独特的方法认为无效。例如，一种方法第一次已经在boost升压电路中提出，但之 后又在升降压变换电路中提出，除此之外，几乎没有变化。手稿以实现不同方式结束，根据 他们的实现、所需要的传感器、检测最大值的能力、成本和适合的应用程序。我们提供了一 个总结主要方法特征的表格。 II. PROBLEM OVERVIEW II.问 题 快递公司问题件快递公司问题件货款处理关于圆的周长面积重点题型关于解方程组的题及答案关于南海问题 概述 Fig. 2 shows the characteristic power curve for a PV array. The problem considered by MPPT techniques is to automatically find the voltage VMPP or current IMPP at which a PV array should operate to obtain the maximum power output PMPP under a given temperature and irradiance. It is noted that under partial shading conditions, in some cases it is possible to have multiple local maxima, but overall there is still only one true MPP. Most techniques respond to changes in both irradiance and temperature, but some are specifically more useful if temperature is approximately constant. Most techniques would automatically respond to changes in the array due to aging, though some are open-loop and would require periodic fine-tuning. In our context, the array will typically be connected to a power converter that can vary the current coming from the PV array. 图二给出了光伏阵列的功率曲线。MPPT技术所要考虑的问题是自动的发现光伏阵列中 电压最大功率点或电流最大功率点，使该光伏阵列在给定的温度和光照下得到最大功率输 出。有人指出，在局部遮挡的情况下，有些时候他可能有多个极大值，但总体来说他只有一 个真正的最大功率点。大部分技术应对温度和光照强度的变换，但是假如温度接近稳定一些 特别的方法将更加有用。大部分技术能自动的对阵列中由老化引起的变化做出响应，尽管一 些是开环控制需要周期性的微调。本文中，阵列和变流器相连，该变流器可以改变电流来自 光伏阵列。 III. MPPT TECHNIQUES III.MPPT技术 We introduce the different MPPT techniques 我们以任意顺序介绍不同的MPPT技 below in an arbitrary order. 术。 A. Hill Climbing/P&O A( 爬坡/扰动与观察 Among all the papers we gathered, much focus 在我们收集的所有论文中， 大多数集中 has been on hill climbing [1]–[8], and perturb and 在爬坡方式[1]-[8],和扰动与观察方式 observe (P&O) [9]–[25] methods. Hill climbing [9]-[25]。在变流器的一个工作周期内爬坡方 involves a perturbation in the duty ratio of the 式包含一个扰动，而扰动与观察方式是包含 power converter, and P&O a perturbation in the 光伏阵列工作电压的一个扰动。就光伏阵列 operating voltage of the PV array. In the case of a 与变流器相连而说，变流器工作周期的扰动 PV array connected to a power converter, 扰乱光伏阵列的电流，进而影响光伏阵列的 perturbing the duty ratio of power converter 电压。爬坡方式和扰动与观察方式是两种不 perturbs the PV array current and consequently 同的方式来设想相同的基本模型。 perturbs the PV array voltage. Hill climbing and P&O methods are different ways to envision the IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 22, NO. 2, JUNE 2007 same fundamental method. From Fig. 2, it can be seen that incrementing 从图二可以看出，随着电压的增长(下(decrementing) the voltage increases (decreases) 降)当作用于最大功率点左侧时功率增长(下the power when operating on the left of the MPP 降)，当作用与最大功率点右侧时功率下降and decreases (increases) the power when on the (增长)。因此，如果功率增长，则随之而来right of the MPP. Therefore, if there is an increase 的扰动将保持相同达到最大功率点;如果功in power, the subsequent perturbation should be 率下降，扰动就会相反。这种算法的总结在kept the same to reach the MPP and if there is a 表I。在[24]中，给出当使用瞬时(而不是平decrease in power, the perturbation should be 均值)光伏阵列电压和电流时这种算法仍然reversed. This algorithm is summarized in Table I. 使用， 只要在一个开关周期内采样一次即In [24], it is shown that the algorithm also works 可。 when instantaneous (instead of average) PV array voltage and current are used, as long as sampling occurs only once in each switching cycle. 图 2.光伏阵列功率曲线 Fig. 2. Characteristic PV array power curve. TABLE I 表 I SUMMARY OF HILL CLIMBING AND P&O ALGORITHM 爬坡算法和扰动与观察方法摘要 The process is repeated periodically until the 此过程要反复进行，直到达到最大功率MPP is reached. The system then oscillates about 点。然后系统在最大功率点附近震荡。在一the MPP. The oscillation can be minimized by 定程度上可以通过减小扰动步长来减小振reducing the perturbation step size. However, a 动。然而一个幅值小的扰动可以降低达到最smaller perturbation size slows down the MPPT. 大功率点的速度。这种矛盾的一种解决 办法 鲁班奖评选办法下载鲁班奖评选办法下载鲁班奖评选办法下载企业年金办法下载企业年金办法下载 A solution to this conflicting situation is to have a 是有一个大小可变的扰动以更小的步长向最variable perturbation size that gets smaller 大功率点移动，在[8][12][15]和[22]中给出，towards the MPP as shown in [8], [12], [15], and 其中在[24]中，模糊逻辑控制使下一个扰动量[22]. In [24], fuzzy logic control is used to 达到最优。在[20]中提出两步运算法则，第一optimize the magnitude of the next perturbation. 步采用快速跟踪，第二步采用最有追踪。另In [20], a two-stage algorithm is proposed that 一方面，[21]通过运用非线性方程估计最初的offers faster tracking in the first stage and finer 工作点接近最大功率点来避开第一步。 tracking in the second stage. On the other hand, IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 22, NO. 2, JUNE 2007 [21] bypasses the first stage by using a nonlinear equation to estimate an initial operating point close to the MPP. Hill climbing and P&O methods can fail under 爬坡方式和扰动与观察方式在快速变化的大rapidly changing atmospheric conditions as 气环境中不起作用，如图3.从工作点A开始，illustrated in Fig. 3. Starting from an operating 如果大气条件保持基本不变，光伏阵列电压point A, if atmospheric conditions stay V的扰动ΔV将工作点变为B，同时由于功率approximately constant, a perturbation ΔV in the 的下降干扰将被反相。可是，如果光照强度PV voltage V will bring the operating point to B 增加使一个周期内的功率曲线由P1变为 and the perturbation will be reversed due to a P2工作点将由A点移至C点。这表示功率， decrease in power. However, if the irradiance 的增长和扰动保持相同。因此，如果光照强increases and shifts the power curve from P1 to P2 度稳定的增加，工作点就会偏离最大功率点within one sampling period, the operating point 并且保持这种偏离状态。为了保证光强突然will move from A to C. This represents an 变化时最大功率点仍然能够被追踪，[18]应用increase in power and the perturbation is kept the 三点比较P&O重要法，该方法是在扰动信号same. Consequently, the operating point diverges 确定之前将先前的两个点和真实的功率点作from the MPP and will keep diverging if the 比较。在[22]中，采样频率是最优的，而在[24]irradiance steadily increases. To ensure that the 中仅仅采用高频率的采样信号。在[8]中，将MPP is tracked even under sudden changes in 传统的爬坡模式算法和改进的自适应的机制irradiance, [18] uses a three-point weight 相结合，以防止与最大功率点的偏差。 comparison P&O method that compares the actual power point to two preceding ones before a decision is made about the perturbation sign. In [22], the sampling rate is optimized, while in [24], simply a high sampling rate is used. In [8], toggling has been done between the traditional hill climbing algorithm and a modified adaptive hill climbing mechanism to prevent deviation from the MPP. 图 3. [9]中给出的爬坡和P&O模式最大功率点的差异 Fig. 3. Divergence of hill climbing/P&O from MPP as shown in [9]. D. Fractional Short-Circuit Current D.定电流跟踪法 定电流跟踪法源于这个事实，在多变的大IFractional results from the fact that, SC II气条件下，光伏阵列的与近似的呈线MPPSC IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 22, NO. 2, JUNE 2007 性关系，在论文[40]，[42]，[45]–[48] 给出 Iunder varying atmospheric conditions, is MPP IkI, ,6, MMPSC2 Iapproximately linearly related to the of the SC k其中为正比例常数。正如定电压跟踪技术2PV array as shown in [40], [42], and [45]–[48] IkI,kk ,6, 中，由使用的光伏阵列确定。常数一般MMPSC222 在0.78-0.92间取值。 kwhere is a proportionality constant. Just like 2 Vkin the fractional technique, has to be OC2 determined according to the PV array in use. The kconstant is generally found to be between 2 0.78 and 0.92. IIMeasuring during operation is 在运行期间测量是有问题的。因此，在SCSC problematic. An additional switch usually has to 变流器上附加一个开关周期性的短接光伏阵be added to the power converter to periodically I列通过电流传感器实现对的测量。这就增SC Ishort the PV array so that can be measured SC加了元器件的数量和成本。在[48]中，运用一using a current sensor. This increases the number 个升压变换器，变换器上的开关可以用来短接of components and cost. In [48], a boost 光伏阵列。 converter is used, where the switch in the converter itself can be used to short the PV array. Power output is not only reduced when finding 功率输出的降低的原因不仅仅由于寻找II but also because the MPP is never perfectly 而且从提出的公式(6)中可以看到，MPPSCSC matched as suggested by (6). In [46], a way of 从来没有很好地匹配。在[46]中，提出一种补 kkcompensating is proposed such that the 偿的方法以至于在大气环境变化时最大功22 MPP is better tracked while atmospheric 率点能很好地被跟踪。在存在多个局部最大点conditions change. To guarantee proper MPPT in 时为了保证完全的最大功率跟踪,[45]周期性the presence of multiple local maxima, [45] k的快速改变开路到短路的电压来更新。文2periodically sweeps the PV array voltage from Ikopen-circuit to short-circuit to update. Most 献中大多数运用部分的光伏系统应用2SC DSP。在[48]中用一个简单的电流控制回路来Iof the PV systems using fractional in the SC代替。 literature use a DSP. In [48], a simple current feedback control loop is used instead E. Fuzzy Logic Control E(模糊逻辑控制 Microcontrollers have made using fuzzy logic 在过去的十年间，微控制器使模糊控制control [49]–[58] popular for MPPT over the last [49]-[58]在最大功率跟踪方面应用变得流行。 IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 22, NO. 2, JUNE 2007 decade. As mentioned in [57], fuzzy logic 如[57]，模糊控制在处理不确定输入和非线性controllers have the advantages of working with 问题方面处于有利条件，而他不需要一个精确imprecise inputs, not needing an accurate 地数学模型。 mathematical model, and handling nonlinearity Fuzzy logic control generally consists of three 模糊控制一般包括三个阶段:模糊化、查stages: fuzzification, rule base table lookup, and 找规则库表、去模糊化。在模糊化过程中，数defuzzification. During fuzzification, numerical 字输入变量被转化成基于隶属度函数的语言input variables are converted into linguistic 变量，如图5.如此看来就有五个模糊子集:variables based on a membership function NB(负方向大的偏差)、NS(负方向小的偏similar to Fig. 5. In this case, five fuzzy levels 差)、ZE(零)、PS(正方向小的偏差)、PBare used: NB (negative big), NS (negative small), (正方向大的偏差)。在[54]和[55]中，应用了ZE (zero), PS (positive small), and PB (positive 七个模糊子集，可能更精确。在图5中，a和big). In [54] and [55], seven fuzzy levels are b的值决定于变量值的范围。隶属度函数有时used, probably for more accuracy. In Fig. 5, a 候是不对称的来更加重视特殊的模糊子集，像and b are based on the range of values of the [49]、[53]、[57]、[58]。 numerical variable. The membership function is sometimes made less symmetric to give more importance to specific fuzzy levels as in [49], [53], [57], and [58]. 图5 输入的隶属度函数和输出的模糊控制 Fig. 5. Membership function for inputs and output of fuzzy logic controller The inputs to a MPPT fuzzy logic controller MPPT模糊控制器的输入通常是一个错 E,EE,E和错误变化。用户可以灵活的选择如误are usually an errorand a change in error. The user has the flexibility of choosing how to E,EdPdV/何计算和。鉴于在最大功率点 E,E为零，[58]应用近似值: dPdV/computeand. Sincevanishes at the MPP, [58] uses the approximation PnPn()(1),, (7) En(),PnPn()(1),,VnVn()(1),, (7) En(),VnVn()(1),,和 And ,,,,EnEnEn()()(1) (8) ,,,,EnEnEn()()(1) (8) E,EE相同的，公式(4)经常用，一旦和Equivalently, (4) is very often used. Once 被计算出来和转化为语言变量，模糊控制器输,Eand are calculated and converted to the linguistic variables, the fuzzy logic controller ,D出，该输出是典型的一个变流器占空比的output, which is typically a change in duty ratio 变化且能在规则库表中被查出，如表II[50]. 表II ,Dof the power converter, can be looked up in [50]中给出的模糊规则库表 a rule base table such as Table II [50]. TABLE II IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 22, NO. 2, JUNE 2007 FUZZY RULE BASE TABLE AS SHOWN IN [50] ,DE,E分配给作为和不同的组合的语,DThe linguistic variables assigned tofor the 言变量以所使用的变流器和用户的知识为基E,Edifferent combinations of and are based on the power converter being used and 础。表II是以升压变换器为基础。如果，举also on the knowledge of the user. Table II is 个例子，工作点在距离最大功率点左边很远的based on a boost converter. If, for example, the E,E地方(图2)，就是 就是PB， 是 ZE，operating point is far to the left of the MPP (Fig. ,D然后我们想增大工作周期，即应该是PB 来达到最大功率点。 E,E2), that is is PB, and is ZE, then we want to largely increase the duty ratio, that is ,D should be PB to reach the MPP. In the defuzzification stage, the fuzzy logic 在去模糊化阶段，模糊控制器的输出由一controller output is converted from a linguistic 个语言变量转变为数值变量仍然应用隶属度variable to a numerical variable still using a 函数像图5。，这就提供了一个模拟信号来控membership function as in Fig. 5. This provides 制变流器达到最大功率点。 an analog signal that will control the power converter to the MPP MPPT fuzzy logic controllers have been 基于模糊控制器的最大功率跟踪在多变shown to perform well under varying 的环境下已经表现出色。但是，它的效率很多atmospheric conditions. However, their 决定于用户或控制工程师选择正确的误差估effectiveness depends a lot on the knowledge of 计和提出规则库表的知识水平。在[55]，提出the user or control engineer in choosing the right 一种自适应模糊控制，该方法不断调整隶属度error computation and coming up with the rule 函数和规则库表已达到最佳操作特性。[51]的base table. In [55], an adaptive fuzzy logic 实验表明该方法能快速收敛于最大功率点和control is proposed that constantly tunes the 波动最小。在[57]中，两个不同的隶属度函数membership functions and the rule base table so 是用来表明跟踪性能取决于对典型隶属度函that optimum performance is achieved. 数考虑 Experimental results from [51] show fast convergence to the MPP and minimal fluctuation about it. In [57], two different membership functions are empirically used to show that the tracking performance depends on the type membership functions considered.