Xingshuo Li

An Improved MPPT Method for PV System With Fast-Converging Speed and Zero Oscillation

Maximum power point tracking (MPPT) is essential for photovoltaic (PV) systems to ensure the highest power output of PV arrays under any environmental condition. Comparing to other techniques, the Beta method shows advantages in terms of tracking speed, steady-state performance, and simple implementation. However, the conventional Beta can further be improved by minimizing oscillations around the maximum power point under a steady state and an increasing tracking speed in response to rapid changing of irradiance or temperature. An improved Beta-parameter-based MPPT method is proposed in this paper to achieve the above-mentioned objectives. An adaptive scaling factor is introduced and utilized in the MPPT mechanism, which enhances the tracking speed and is easily applied for any PV power system. Furthermore, the proposed method can identify and maintain the middle point of the three-level perturbations, which eliminate the oscillations at a steady state. The control mechanism is not limited by specific operating conditions and illustrates superior performance over traditional methods with regards to transient response and steady-state performance, which contributes to effective solar power harvesting. Followed by theoretical analysis, the simulation and experimental evaluation validate the claimed advantages of the proposed MPPT solution.

An Improved Beta Method With Autoscaling Factor for Photovoltaic System

Maximum power point tracking (MPPT) is essential to improve the energy yield of solar energy systems. However, conventional MPPT algorithms show obvious problems such as the conflict of the steady-state oscillations and dynamic speed, and the clash of high computational burden and accuracy. Originated from the beta method, which shows the advantages of fast tracking speed in the transient stage, small oscillations in the steady-state, and medium complexity of implementation, this paper proposed an improved beta method to further improve the overall performance, especially for practical applications. Instead of manually tuning key parameters such as the range of β parameter and scaling factor N for different operating conditions, an autoscaling factor is used, which make the method easier in practical implementation and suitable for wider conditions. The meteorological data of two distinct locations are used to verify that the β parameters derived from photovoltaic (PV) modules are valid for one whole year under different environmental conditions. A PV system with the proposed MPPT method was built in MATLAB/Simulink, and different indices such as the rise time, the setting time, and the tracking energy loss are used to evaluate the performance of various MPPT algorithms. Finally, two experimental tests were carried out, including the indoor test with solar array emulator and the outdoor test with an actual PV module, respectively, to show the effectiveness of the proposed MPPT algorithm.

Photovoltaic Modified β-Parameter-based MPPT Method with Fast Tracking

Maximum power point tracking (MPPT) is necessary for photovoltaic (PV) power system application to extract the maximum possible power under changing irradiation and temperature conditions. The β-parameter-based method has many advantages over conventional MPPT methods; such advantages include fast tracking speed in the transient stage, small oscillations in the steady state, and moderate implementation complexity. However, a problem in the implementation of the conventional beta method is the choice of an appropriate scaling factor N, which greatly affects both the steady-state and transient performance. Therefore, this paper proposes a modified β-parameter-based method, and the determination of the N is discussed in detail. The study shows that the choice of the scaling factor N is determined by the changes of the value of β during changes in irradiation or temperature. The proposed method can respond accurately and quickly during changes in irradiation or temperature. To verify the proposed method, a photovoltaic power system with MPPT function was built in Matlab/Simulink, and an experimental prototype was constructed with a solar array emulator and dSPACE. Simulation and experimental results are illustrated to show the advantages of the improved β-parameter-based method with the optimized scaling factor.

Evaluation of different maximum power point tracking (MPPT) techniques based on practical meteorological data

Recently, many Maximum power point tracking (MPPT) techniques are proposed in the Photovoltaic (PV) systems. However, a comprehensive comparison of various MPPT techniques especially the dynamic tracking performance has not been made quantitatively for different working conditions. By reviewing different methods, the day-by-day operating evaluation method with practical meteorological data is used in this paper. Furthermore, three typical MPPT techniques including fixed step size P&O method, variable step size incremental conductance method, and hybrid step size Beta method, are selected in the performance evaluation. In order to improve the experimental repeatability and minimize the effect of random environmental factor such as partial shading, an indoor test system that consists of a DC-DC boost converter, a PV emulator and a dSPACE is used. The practical meteorological data are used for the evaluation these typical MPPT techniques and main experimental results are presented.

Perturbation optimization of maximum power point tracking of photovoltaic power systems based on practical solar irradiance data

There is a dilemma for fixed step perturb-and-observe (P&O) maximum power point tracking (MPPT) method which is the tracking accuracy and speed. The idea of this paper is to propose an optimized solution which can be regard as a trade-off between performance and cost. The optimal selection of the perturb step size will be designed off-line for a specific location based on their local meteorological data. The step size also can be updated monthly for better system performance without increasing the control complexity. Simulation and experiments have been carried out to verify the effectiveness and superiority of the proposed method. The experimental results show an example with 5.8% of energy generation increase by selecting optimal step size based on the local irradiance data.

Improved beta parameter based MPPT method in photovoltaic system

Maximum power point tracking(MPPT) is very important in relation to solar energy development. Currently, there are two problems facing the existing MPPT methods namely the tradeoff between the steady-state oscillations and dynamic behavior, and then the tradeoff between high computational load and accuracy. The Beta method can address these two problems since it shows a fast tracking speed in the transient stage, smaller oscillations in the steady-state and medium complexity of implementation. However, for optimal performance, it is essential to identify the configuration of the parameters with regard to the Beta method. Therefore, paper will examine the different performance level with the different values of the parameters, and then will provide an optimum example. In order to verify this procedure, a boost converter was proposed in MatLab/Simulink for simulation. Finally, an experimental prototype was constructed with a solar array emulator and DSPACE.

Modified Beta Algorithm for GMPPT and Partial Shading Detection in Photovoltaic Systems

When the photovoltaic (PV) string is under the partial shading condition (PSC), the conventional maximum power point tracking (MPPT) techniques may fail to track the global maximum power point (GMPP). Although some global MPPT (GMPPT) techniques have been proposed, they may overlook the GMPP and fail to detect the PSC occurrence. Therefore, a novel GMPPT technique is proposed in this paper by modifying the conventional beta method. The proposed technique is more accurate than the previous techniques since it can guarantee that all the peaks in the

A fuzzy logic controller with beta parameter for maximum power point tracking of Photovoltaic systems

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Minimum-power-tracking for PV-PV differential power processing systems

range and never overlook the GMPP. Furthermore, the proposed technique can inherently detect the PSC occurrence without setting any additional threshold parameters or periodical interruption, which is simpler and more effective. In order to verify the advantages of the proposed technique, a prototype with buck-boost converter was constructed. For a fair comparison, two popular GMPPT techniques were also implemented and tested in the same prototype under various scenarios. The performance improvement with the proposed technique for different PSCs has been validated by both simulation and experimental results.

Distributed MPPT control under partial shading condition

This paper presents a fuzzy logic controller(FLC) for maximum power point tracking (MPPT) of Photovoltaic (PV) systems. Unlike the conventional FLC methods, which generally have two inputs parameters for the FLC, the proposed FLC method has three input parameters. An intermediate variable beta is integrated into the proposed FLC method, which can simplify the design of FLC. Moreover, converging speed and oscillation are further improved by the proposed method. A comparison between the proposed FLC and the conventional MPPT methods are conducted during varying solar irradiation levels. Simulation and experimentation results are provided to demonstrates the validity of the proposed FLC.