Power Point Of Photovoltaic Array Research Articles

An Immune Firefly Algorithm for Tracking the Maximum Power Point of PV Array under Partial Shading Conditions

Photovoltaic (PV) string exhibits complex multiple-peak characteristics under various partial shading conditions (PSC). If the maximum power point tracking cannot be achieved quickly and accurately, it will lead to a large amount of energy loss. Therefore, it has become a hot topic to study a reliable maximum power tracking control algorithm to ensure the PV system can still output maximum power under PSC. This paper proposes an immune firefly algorithm (IFA), which utilizes vaccine data-base to shorten the convergence time, eliminates the influence of bad individuals in time by immune replenishment operation, and reduces the steady-state oscillation by the improving iteration formula. The simulations in static and dynamic environments verify that the immune firefly algorithm can track the maximum power point under various partial shading conditions. Compared with conventional firefly algorithm (FA), IFA has faster convergence speed, and can effectively restrain the oscillation of voltage and power.

Maximum Power Point Tracking of PV Systems Based On a Novel Adaptive Variable Step Size INC MPPT Method

In the future solar energy will become a very important green energy. Maximum power point (MPP) tracking (MPPT) technology is widely used in solar photovoltaic (PV) systems to generate peak power for PV arrays that depend on solar irradiation and ambient temperature. Literature[1] shows that the maximum power point tracking (MPPT) technology can improve the efficiency of photoelectric conversion by more than 20% and the economic cost is relatively low. Based on PROTUES, the output characteristics of PV arrays under different shadow conditions are simulated and the rule between local maximum power point and open circuit voltage is obtained. Among all the MPPT strategies, the incremental conductance (INC) algorithm and perturb and observe (P&O) algorithm are widely used due to the high tracking accuracy at steady state and easy implementation.In this paper, a novel adaptive variable step size INC MPPT method is proposed according to the above rule. This algorithm not only has the advantage of INC, but also can automatically adjust the step size to track the maximum power point of PV arrays. Compared with the adaptive perturb and observe (P&O) algorithm, the proposed approach can effectively improve the MPPT steady-state response speed and accuracy simultaneously. The theoretical analysis and design principle of the proposed algorithm are presented in this paper. The simulation results show that the algorithm can accurately track the maximum power point (MPP) with shadow. The average tracking time is only 0.13 seconds, and the power tracking efficiency reaches 98%.

MPPT and Power Factor Control for Grid Connected PV Systems with Fuzzy Logic Controllers

Two fuzzy logic controllers are proposed in this paper to control a three phase inverter for grid connected photovoltaic system. The first controller was used to predict the DC voltage that allows the three phase inverter to track the maximum power point of photovoltaic array under different environmental conditions such as irradiances and temperature. The second was used to control the active power and reactive power injected into the grid in order to inject the maximum active power produced by photovoltaic systems into grid with high efficiency and low total harmonic distortion using the same three phase inverter. The system components are photovoltaic array, DC link voltage, three-phase inverter, inverter control, LC filter, transformer and grid. To verify the effectivnesse of the introdueced system, modeling and simulation are verified in Matlab/Simulink due to its frequent use and its effectiveness.

Dual‐coupled inductors‐based high step‐up DC/DC converter without input electrolytic capacitor for PV application

To alleviate the power losses caused by the fluctuation of the output current of the photovoltaic (PV) array, a DC/DC converter with high-voltage gain is proposed for PV generation systems. The input current ripples of the proposed converter can be greatly reduced by making use of coupled inductors. Then the electrolytic capacitor on the input side could be replaced by polypropylene capacitor with smaller capacity and size. In addition, the snubber and the energy recovery circuits constructed by diodes and storage capacitors can be operated to reduce the voltage spikes of the switch tubes and losses caused by the leakage inductance. Based on analysing the inherent five operating modes of the proposed converter, high-voltage gain and the zero input current ripples characteristics of the proposed converter is manifested. The theoretical analysis is then verified by a 150 W-rated experimental prototype, and the results show that the proposed converter can quickly and accurately trace the maximum power point of PV array based on the modified incremental conductance method with high-voltage gain and low current ripples.

Tracking Algorithms and Voltage Controllers Used to Obtain the Maximum Power Point of PV Arrays

In this paper, a fuzzy proportional derivative and/or a classical proportional integral is used to control the terminal voltage of the photovoltaic (PV) array connected to the input of a dc/dc step-up converter. The voltage reference is tracked continuously by employing a perturb and observe and the incremental conductance algorithms in order to make the PV array operate as close as possible to the maximum power point (MPP). However, these techniques produce oscillations around the MPP, which can be reduced by applying adaptive steps instead of fixed steps. Additionally, this paper presents the complete mathematical model of the power converter associated with a PV array where the parasitic elements are included. Simulations and experimental results under different environmental conditions are presented to demonstrate the effectiveness of the proposed approach.

Comparison of Artificial Bee Colony Algorithm with other Algorithms used for Tracking of Maximum Power Point of Photovoltaic Arrays

Maximum power point tracker (MPPT) is one of the key components of a solar electricity generation systems. It is used to extract the maximum power produced by an array of Photovoltaic cells. In this paper Artificial Bee Colony algorithm is analysed and implemented for tracking the maximum power point of Photovoltaic arrays. Furthermore the results obtained from ABC algorithm are compared with that of Perturb and Observe method, Fuzzy Logic Control and Genetic Algorithms.

MPPT for Photovoltaic System Using Multi-objective Improved Particle Swarm Optimization Algorithm

Making full use of abundant renewable solar energy through the development of photovoltaic (PV) technology is an effective means to solve the problems such as difficulty in electricity supply and energy shortages in remote rural areas. In order to improve the electricity generating efficiency of PV cells, it is necessary to track the maximum power point of PV array, which is difficult to make under partially shaded conditions due to the odds of the appearance of two or more local maximum power points., In this paper, a control algorithm of maximum power point tracking (MPPT) based on improved particle swarm optimization (IPSO) algorithm is presented for PV systems. Firstly, the current in maximum power point is searched with the IPSO algorithm, and then the real maximum power point is tracked through controlling the output current of PV array.,. The MPPT method based on IPSO algorithm is established and simulated with Matlab / Simulink, and meanwhile, the comparison between IPSO MPPT algorithm and traditional MPPT algorithm is also performed in this paper. It is proved through simulation and experimental results that the IPSO algorithm has good performances and very fast response even to partial shaded PV modules, , which ensures the stability of PV system. DOI : http://dx.doi.org/10.11591/telkomnika.v12i1.3965

A modular strategy for isolated photovoltaic systems based on microcontroller

Many different types of commercial regulators can be found in the market. These devices can be basically divided into two categories according to their operation mode: those which modulate the input voltage using PWM (pulse-width modulation) in order to generate the output voltage required to charge the batteries; and those which make the PV (photovoltaic) array operate in their MPP (maximum power point), which can be tracked in several different ways. The former are normally used for low-power applications, whereas the latter can provide an increase of power up to 25% as compared to their PWM counterpart. This paper presents a regulator which can operate in the maximum power point of PV arrays by means of a microcontroller. A simple, highly-accurate algorithm suitable to be implemented in a low-cost microcontroller has been developed in order to make PV arrays track and operate in their maximum power point. The control strategy proposed allows parallel connection of different regulators, thus making it possible to keep and integrate previous equipment.

産業用PV連系システムの平準化運転方法に関する研究

We suggest a grid-connected photovoltaic (PV) system in which PV arrays and batteries are connected directly in DC side. In this system, batteries are discharged or charged under control by power-conditioner which converts the mixed output of PV arrays and batteries without a DC-DC converter for converting a battery voltage. Despite a shift of a power point of PV arrays from maximum power point, it is possible to increase power generation of PV arrays because conversion loss of the DC-DC converter can be removed. As a result of numerical simulations, it is found that the power generation ratio of this system to MPPT system reaches to 97.4%.

Dynamic maximum power point tracking of photovoltaic arrays using ripple correlation control

A dynamically rapid method used for tracking the maximum power point of photovoltaic arrays, known as ripple correlation control, is presented and verified against experiment. The technique takes advantage of the signal ripple, which is automatically present in power converters. The ripple is interpreted as a perturbation from which a gradient ascent optimization can be realized. The technique converges asymptotically at maximum speed to the maximum power point without the benefit of any array parameters or measurements. The technique has simple circuit implementations

On the control of photovoltaic maximum power point tracker via output parameters

A new approach for tracking the maximum power point of photovoltaic arrays is presented. The maximum power point tracker output voltage and current are used for control purposes, rather than for its input voltage and current. It is shown that using the output parameters simplifies the maximum power point tracker controller. Moreover, using this approach, only one out of the two output parameters needs to be sensed. This observation is general and applies regardless of the power stage or the realisation control algorithm. Contrary to what might have previously been assumed, it is theoretically shown that the MPPT control that uses a single output control parameter applies to nearly all practical load types, regardless of the load nature.