共查询到20条相似文献,搜索用时 15 毫秒
1.
The one of main causes of reducing energy yield of photovoltaic systems is partially shaded conditions. Although the conventional maximum power point tracking (MPPT) control algorithms operate well under uniform insolation, they do not operate well in non-uniform insolation. The non-uniform conditions cause multiple local maximum power points on the power?voltage curve. The conventional MPPT methods cannot distinguish between the global and local peaks. Since the global maximum power point (MPP) may change within a large voltage window and also its position depends on shading patterns, it is very difficult to recognise the global operating point under partially shaded conditions. In this paper, a novel MPPT system is proposed for partially shaded PV array using artificial neural network (ANN) and fuzzy logic with polar information controller. The ANN with three layer feed-forward is trained once for several partially shaded conditions to determine the global MPP voltage. The fuzzy logic with polar information controller uses the global MPP voltage as a reference voltage to generate the required control signal for the power converter. Another objective of this study is to determine the estimated maximum power and energy generation of PV system through the same ANN structure. The effectiveness of the proposed method is demonstrated under the experimental real-time simulation technique based dSPACE real-time interface system for different interconnected PV arrays such as series-parallel, bridge link and total cross tied configurations. 相似文献
2.
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。 相似文献
3.
In addition to the conversion efficiency of a photovoltaic panel, the maximum power point tracking (MPPT) method also plays a central role to harvest most energy out of sun. The MPPT unit on a moving vehicle must keep tracking accuracy high in order to compensate rapid change of insolation due to dynamic motion of the vehicle. In this paper, some problems of a PV system associated with a moving vehicle are addressed, and a modified quadratic maximization MPPT algorithm is proposed. Theoretical PV performance is linked to the experimental test followed by the Sandia dynamic test protocol to verify the proposed MPPT method. Finally, experimental result on a model ship is discussed. 相似文献
4.
5.
T. Ikegami T. Maezono F. Nakanishi Y. Yamagata K. Ebihara 《Solar Energy Materials & Solar Cells》2001,67(1-4)
A method to estimate the equivalent circuit parameters of a PV (photovoltaic) module is presented. The parameters are calculated using a least-squares fitting of the equivalent model current–voltage characteristic with the measured one. For applications of the equivalent circuit model parameters, a quantitative diagnostic method of the PV modules by evaluating the parameters is introduced and examined by simulation. A new maximum peak power tracking (MPPT) method using the model parameters, a solar insolation, and a cell temperature is also shown. Its performance is compared with other MPPT control algorithms by simulations. The performance of the proposed method was better than other MPPT methods. 相似文献
6.
A. Zegaoui M. Aillerie P. Petit J.P. Sawicki J.P. Charles A.W. Belarbi 《Solar Energy》2011,85(11):2953-2964
Maximum power point trackers (MPPTs) have a decisive role to extract power from the photovoltaic (PV) generators as they have to assume the maximum power output (MPP) whatever are the continuous changes of temperature and irradiation conditions. Therefore, they take a prior place in the global PV system efficiency. These trackers are driven by MPPT algorithms and lot of these MPPT algorithms are proposed in literature. The two most common implemented algorithms for power optimisation are the Perturb and Observe (P&O) and the Incremental of Conductance (IncCond) algorithms, which present a high simplicity of implementation within electronics programmable circuits. With an approach based on realistic parameters such as those found when the generator is integrated in a real photovoltaic installation, the two MPPT techniques are dynamically compared using testing procedures developed with Matlab/Simulink. The study leads us to conclude that both algorithms can be performed for PV exposures in unfavourable but realistic external conditions. 相似文献
7.
Harun Özbay Selim Öncü Metin Kesler 《International Journal of Hydrogen Energy》2017,42(28):17713-17722
In this paper, sliding mode control (SMC) – direct power controller (DPC) based active and reactive power controller for three-phase grid-tied photovoltaic (PV) system is proposed. The proposed system consists of two main controllers: the DC/DC boost converter to track the possible maximum power from the PV panels and the grid-tied three-phase inverter. The Perturb and Observe (P&O) algorithm is used to transfer the maximum power from the PV panels. Control of the active and reactive powers is performed using the SMC-DPC strategy without any rotating coordinate transformations or phase angle tracking of the grid voltage. In addition, extra current control cycles are not used to simplify the system design and to increase transient performance. The fixed switching frequency is obtained by using space vector modulation (SVM). The proposed system provides very good results both in transient and steady states with the simple algorithms of P&O and SMC-DPC methods. Moreover, the results are evaluated by comparing the SMC-DPC method developed for MPPT and the traditional PI control method. The proposed controller method is achieved with TMS320F28335 DSP processor and the system is experimentally tested for 12 kW PV generation systems. 相似文献
8.
The aim of this article is to describe how closely PV grid-connected inverters (of around 5 kW) operate at the actual maximum power point. These inverters could be installed at any low voltage, PV grid-connected systems. To carry this study out, twelve 50 Hz single-phase inverters were selected from the European market. Each one of them was put into an outdoor grid-connected system installed in Spain. PV power generation with respect to irradiance, ambient temperature and local time was measured under different meteorological conditions. DC voltage and maximum power point tracking efficiency were analyzed. From the results obtained it has been possible to see that the MPPT algorithms used in some inverters do not bring the optimum utilisation of the PV array. 相似文献
9.
Hardik P. Desai Ranjan Maheshwari Shambhu N. Sharma Varsha Shah 《Applied Solar Energy》2010,46(4):251-257
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. 相似文献
10.
This paper presents a single stage transformer-less grid-connected solar photovoltaic (PV) system with an active and reactive power control. In the absence of active input power, the grid-tied voltage source converter (VSC) is operated in a reactive power generation mode, which powers the control circuitry, and maintains a regulated DC voltage to the VSC. A data-based maximum power point tracking (MPPT) control scheme which performs power quality control at a maximum power by reducing the total harmonic distortion (THD) in grid injected current as per IEEE-519/1547 standards is implemented. A proportional-integral (PI) controller based dynamic voltage restorer (DVR) control scheme is implemented which controls the grid side converter during single-phase to ground fault. The analysis includes the grid current THD along with the corresponding variation of the active and reactive power during the fault condition. The MPPT tracks the actual variable DC link voltage while deriving the maximum power from the solar PV array, and maintains the DC link voltage constant by changing the modulation index of the VSC. Simulation results using Matlab/Simulink are presented to demonstrate the feasibility and validations of the proposed novel MPPT and DVR control systems under different environmental conditions. 相似文献
11.
王玮茹 《电网与水力发电进展》2011,27(6):61-64
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。 相似文献
12.
13.
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. 相似文献
14.
15.
Wu Libo Zhao Zhengming Liu Jianzheng 《Energy Conversion, IEEE Transaction on》2007,22(4):881-886
Single-stage grid-connected photovoltaic (PV) systems have advantages such as simple topology, high efficiency, etc. However, since all the control objectives such as the maximum power point tracking (MPPT), synchronization with the utility voltage, and harmonics reduction for output current need to be considered simultaneously, the complexity of the control scheme is much increased. This paper presents the implementation of a single-stage three-phase grid-connected PV system. In addition to realize the aforementioned control objectives, the proposed control can also remarkably improve the stability of the MPPT method with a modified incremental conductance MPPT method. The reactive power compensation for local load is also realized, so as to alleviate grid burden. A DSP is employed to implement the proposed MPPT controller and reactive power compensation unit. Simulation and experimental results show the high stability and high efficiency of this single-stage three-phase grid-connected PV system. 相似文献
16.
A novel multi-model neuro-fuzzy-based MPPT for three-phase grid-connected photovoltaic system 总被引:1,自引:0,他引:1
This paper presents a novel methodology for Maximum Power Point Tracking (MPPT) of a grid-connected 20 kW photovoltaic (PV) system using neuro-fuzzy network. The proposed method predicts the reference PV voltage guarantying optimal power transfer between the PV generator and the main utility grid. The neuro-fuzzy network is composed of a fuzzy rule-based classifier and three multi-layered feed forwarded Artificial Neural Networks (ANN). Inputs of the network (irradiance and temperature) are classified before they are fed into the appropriated ANN for either training or estimation process while the output is the reference voltage. The main advantage of the proposed methodology, comparing to a conventional single neural network-based approach, is the distinct generalization ability regarding to the nonlinear and dynamic behavior of a PV generator. In fact, the neuro-fuzzy network is a neural network based multi-model machine learning that defines a set of local models emulating the complex and nonlinear behavior of a PV generator under a wide range of operating conditions. Simulation results under several rapid irradiance variations proved that the proposed MPPT method fulfilled the highest efficiency comparing to a conventional single neural network and the Perturb and Observe (P&O) algorithm dispositive. 相似文献
17.
It is crucial to improve the photovoltaic (PV) system efficiency and to develop the reliability of PV generation control systems. There are two ways to increase the efficiency of PV power generation system. The first is to develop materials offering high conversion efficiency at low cost. The second is to operate PV systems optimally. However, the PV system can be optimally operated only at a specific output voltage and its output power fluctuates under intermittent weather conditions. Moreover, it is very difficult to test the performance of a maximum-power point tracking (MPPT) controller under the same weather condition during the development process and also the field testing is costly and time consuming. This paper presents a novel real-time simulation technique of PV generation system by using dSPACE real-time interface system. The proposed system includes Artificial Neural Network (ANN) and fuzzy logic controller scheme using polar information. This type of fuzzy logic rules is implemented for the first time to operate the PV module at optimum operating point. ANN is utilized to determine the optimum operating voltage for monocrystalline silicon, thin-film cadmium telluride and triple junction amorphous silicon solar cells. The verification of availability and stability of the proposed system through the real-time simulator shows that the proposed system can respond accurately for different scenarios and different solar cell technologies. 相似文献
18.
19.
A study of a two stage maximum power point tracking control of a photovoltaic system under partially shaded insolation conditions 总被引:1,自引:0,他引:1
Kenji Kobayashi Ichiro Takano Yoshio Sawada 《Solar Energy Materials & Solar Cells》2006,90(18-19):2975-2988
A photovoltaic (PV) array shows relatively low output power density, and has a greatly drooping current–voltage (I–V) characteristic. Therefore, maximum power point tracking (MPPT) control is used to maximize the output power of the PV array. Many papers have been reported in relation to MPPT. However, the current–power (I–P) curve sometimes shows multi-local maximum point mode under non-uniform insolation conditions. The operating point of the PV system tends to converge to a local maximum output point which is not the real maximal output point on the I–P curve. Some papers have been also reported, trying to avoid this difficulty. However, most of those control systems become rather complicated. Then, the two stage MPPT control method is proposed in this paper to realize a relatively simple control system which can track the real maximum power point even under non-uniform insolation conditions. The feasibility of this control concept is confirmed for steady insolation as well as for rapidly changing insolation by simulation study using software PSIM and LabVIEW. 相似文献
20.
在局部阴影的情况下,由于串联式光伏组件的输出特性不同而产生多个极值点,使得传统的最大功率追踪(maximum power point tracking, MPPT)方法陷入局部极值点而失效。文中提出一种针对两级并网光伏系统的改进电导增量法以适应光伏阵列在局部阴影下的多峰值最大功率跟踪,通过分析最大功率点电压的变化范围,设定最大功率电压搜索范围以提高搜索效率,并通过DC/DC Boost变换器占空比实现输入电压控制,保证算法不陷入局部极值点。最后利用仿真实验验证了该算法在有、无阴影情况下均能准确地跟踪光伏方阵最大功率,有效提高了光伏阵列输出效率。 相似文献