A Phase-Shift-Modulated LLC-Resonant Micro-Inverter Based on Fixed Frequency Predictive-MPPT

Maximum Power Point Tracking (MPPT) control is an essential part of every photovoltaic (PV) system, in order to overcome any change in ambient environmental conditions and ensure operation at maximum power.. Recently, micro-inverters have gained a lot of attention due to their ability to track the true MPP for each individual PV module, which is considered a powerful solution to overcome the partial shading and power mismatch problems which exist in series-connected panels. Although the LLC resonant converter has high efficiency and high boosting ability, traditional MPPT techniques based on Pulse Width Modulation (PWM) do not work well with it. In this paper, a fixed frequency predictive MPPT technique is presented for the LLC resonant converter to be used as the first-stage in a PV micro-inverter. Using predictive control enhances the tracking efficiency and reduces the steady state oscillation. Operation with fixed switching frequency for the LLC resonant converter improves the total harmonic distortion profile of the system and ease the selection of circuit magnetic component. To demonstrate the effectiveness of the proposed MPPT technique, the system is simulated using MATLAB/Simulink platform. Furthermore, a 150 W hardware prototype is developed and tested. Both simulation and experimental results are consistent and validate the proper operation of the developed system.

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High-Flexibility MPPT Techniques with Communication Scan Network for PV Micro-Grid System

Processes ◽

10.3390/pr10010117 ◽

2022 ◽

Vol 10 (1) ◽

pp. 117

Author(s):

Yu-Kai Chen ◽

Hong-Wen Hsu ◽

Chau-Chung Song ◽

Yu-Syun Chen

Keyword(s):

Output Voltage ◽

High Efficiency ◽

Maximum Power ◽

Global Maximum ◽

Switching Frequency ◽

Grid System ◽

Pv System ◽

In Series ◽

Micro Grid ◽

High Flexibility

This paper proposes the design and implementation of inductor-inductor-capacitor (LLC) converters with modules connected in series with the power scan method and communication scan network (CSN) to achieve MPPT and regulate the output voltage for the PV micro-grid system. The Dc/Dc converters includes six isolated LLC modules in series to supply ±380 V output voltage and track the maximum power point of the PV system. The series LLC converters are adopted to achieve high efficiency and high flexibility for the PV micro-grid system. The proposed global maximum power scan technique is implemented to achieve global maximum power tracking by adjusting the switching frequency of the LLC converter. To improve the system flexibility and achieve system redundancy, module failure can be detected in real time with a communication scan network, and then the output voltage of other modules will be changed by adjusting the switching frequency to maintain the same voltage as before the failure. Additionally, the proposed communication scan network includes the RS-485 interface of the MPPT series module and the CAN BUS communication interface with other subsystems’ communication for the PV micro-grid application system. Finally, a 6 kW MPPT prototype with a communication scan network is implemented and the proposed control method is verified for the PV system.

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A Comparative Study on Maximum Power Point Tracking Techniques of Photovoltaic Systems

International Journal of Energy Optimization and Engineering ◽

10.4018/ijeoe.2018010104 ◽

2018 ◽

Vol 7 (1) ◽

pp. 66-85 ◽

Cited By ~ 2

Author(s):

Afef Badis ◽

Mohamed Habib Boujmil ◽

Mohamed Nejib Mansouri

Keyword(s):

High Efficiency ◽

Maximum Power Point Tracking ◽

Maximum Power ◽

Pv System ◽

Maximum Power Point ◽

Partial Shading ◽

Point Tracking ◽

Power Point Tracking ◽

Conventional Methods ◽

Power Point

This article concerns maximizing the energy reproduced from the photovoltaic (PV) system, ensured by using an efficient Maximum Power Point Tracking (MPPT) process. The process should be fast, rigorous and simple for implementation because the PV characteristics are extremely affected by fast changing conditions and Partial Shading (PS). PV systems are popularly known to have many peaks (one Global Peak (GP) and several local peaks). Therefore, the MPPT algorithm should be able to accurately detect the unique GP as the maximum power point (MPP), and avoid any other peak to mitigate the effect of (PS). Usually, with no shading, nearly all the conventional methods can easily reach the MPP with high efficiency. Nonetheless, they fail to extract the GP when PS occurs. To overcome this problem, Evolutionary Algorithms (AEs), namely the Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) are simulated and compared to the conventional methods (Perturb & Observe) under the same software.

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Dual Interleaved LLC Converter for High Power Applications and Wide Load Range

Elektronika ir Elektrotechnika ◽

10.5755/j01.eie.25.3.23669 ◽

2019 ◽

Vol 25 (3) ◽

pp. 4-9

Author(s):

Michal Frivaldsky ◽

Jan Morgos ◽

Andrej Kanovsky

Keyword(s):

High Power ◽

High Efficiency ◽

Negative Impact ◽

Power Converter ◽

Switching Frequency ◽

Resonant Converter ◽

Load Range ◽

High Switching Frequency ◽

Llc Resonant Converter ◽

Operational Range

Dual interleaved LLC resonant converter with half bridge topology of main circuit characterized by high switching frequency (500 kHz), high power density (60 W/inch3) and high efficiency (above 96 %) over entire operational range (20 %–100 %) is described. Focus was given on the practical design of power converter, which will be able to fulfil requirements on wide load range operation characterized by upcoming normative. Since proposed topology is based on dual interleaved LLC converter, the resonant component´s critical tolerance was also investigated to secure reliable and optimal operational point. Consequently, proposals for elimination of intolerance negative impact are also described. The results of theoretical analysis were verified directly through experimental measurements. Experimental results are finally compared with upcoming industrial standard 80 Plus Titanium.

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Maximum power point tracking of partially shading PV system using cuckoo search algorithm

International Journal of Power Electronics and Drive Systems (IJPEDS) ◽

10.11591/ijpeds.v10.i2.pp1081-1089 ◽

2019 ◽

Vol 10 (2) ◽

pp. 1081 ◽

Cited By ~ 2

Author(s):

Ahmed Ibrahim ◽

Raef Aboelsaud ◽

Sergey Obukhov

Keyword(s):

High Efficiency ◽

Search Algorithm ◽

Cuckoo Search ◽

Cuckoo Search Algorithm ◽

Maximum Power ◽

Global Maximum ◽

Pv System ◽

Maximum Power Point ◽

Partial Shading ◽

Power Point

This paper presents a cuckoo search (CS) algorithm for determining the global maximum power point (GMPP) tracking of photovoltaic (PV) under partial shading conditions (PSC). The conventional methods are fail to track the GMPP under PSC, which decrease the reliability of the power system and increase the system losses. The performance of the CS algorithm is compared with perturb and observe (P&O) algorithm for different cases of operations of PV panels under PSC. The CS algorithm used in this work to control directly the duty cycle of the DC-DC converter without proportional integral derivative (PID) controller. The proposed CS model can track the GMPP very accurate with high efficiency in less time under different conditions as well as in PSC.

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Control of Power and Voltage of Solar Grid Connected

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v6i1.pp26-33 ◽

2016 ◽

Vol 6 (1) ◽

pp. 26 ◽

Cited By ~ 2

Author(s):

Boucetta Abd Allah ◽

Labed Djamel

Keyword(s):

Control Strategy ◽

High Efficiency ◽

Harmonic Distortion ◽

Maximum Power ◽

Photovoltaic System ◽

Pv System ◽

Maximum Power Point ◽

Three Phase ◽

Power Point ◽

Computational Resources

Renewable energy is high on international agendas. Currently, grid-connected photovoltaic systems are a popular technology to convert solar energy into electricity. Control of power injected into the grid, maximum power point, high efficiency, and low total harmonic distortion of the currents injected into the grid are the requirements for inverter connection into the grid. Consequently, the performance of the inverters connected to the grid depends largely on the control strategy applied. In this paper the simulation and design of grid connected three phase photovoltaic system using Matlab/Simulink has examined. The proposed system consists photovoltaic panels, boost and inverter the PV system convert the sun irradiation into direct current, thereafter we have used a boost to track the maximum power point of the PV system, three-phase inverter and LC output filter. A VOC control strategy based on the phase shifting of the inverter output voltage with respect to the grid voltage. The proposed control strategy requires few hardware and computational resources. As a result, the inverter implementation is simple, and it becomes an attractive solution for low power grid connected applications.

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High-Frequency LLC Resonant Converter with GaN Devices and Integrated Magnetics

Energies ◽

10.3390/en12091781 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1781 ◽

Cited By ~ 5

Author(s):

Yu-Chen Liu ◽

Chen Chen ◽

Kai-De Chen ◽

Yong-Long Syu ◽

Meng-Chi Tsai

Keyword(s):

High Frequency ◽

High Efficiency ◽

Power Converter ◽

Maximum Efficiency ◽

Switching Frequency ◽

Resonant Converter ◽

Leakage Inductance ◽

Llc Resonant Converter ◽

Resonant Inductor ◽

Secondary Side

In this study, a light emitting diode (LED) driver containing an integrated transformer with adjustable leakage inductance in a high-frequency isolated LLC resonant converter was proposed as an LED lighting power converter. The primary- and secondary-side topological structures were analyzed from the perspectives of component loss and component stress, and a full-bridge structure was selected for both the primary- and secondary-side circuit architecture of the LLC resonant converter. Additionally, to achieve high power density and high efficiency, adjustable leakage inductance was achieved through an additional reluctance length, and the added resonant inductor was replaced with the transformer leakage inductance without increasing the amount of loss caused by the proximity effect. To optimize the transformer, the number of primary- and secondary-side windings that resulted in the lowest core loss and copper loss was selected, and the feasibility of the new core design was verified using ANSYS Maxwell software. Finally, this paper proposes an integrated transformer without any additional resonant inductor in the LLC resonant converter. Transformer loss is optimized by adjusting parameters of the core structure and the winding arrangement. An LLC resonant converter with a 400 V input voltage, 300 V output voltage, 1 kW output power, and 500 kHz switching frequency was created, and a maximum efficiency of 97.03% was achieved. The component with the highest temperature was the transformer winding, which reached 78.6 °C at full load.

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A Dragonfly Optimization Algorithm for Extracting Maximum Power of Grid-Interfaced PV Systems

Sustainability ◽

10.3390/su131910778 ◽

2021 ◽

Vol 13 (19) ◽

pp. 10778

Author(s):

Ehtisham Lodhi ◽

Fei-Yue Wang ◽

Gang Xiong ◽

Ghulam Ali Mallah ◽

Muhammad Yaqoob Javed ◽

...

Keyword(s):

Optimization Algorithm ◽

High Efficiency ◽

Reactive Power ◽

Maximum Power ◽

Fruit Fly Optimization Algorithm ◽

Pv System ◽

Partial Shading ◽

Matlab Simulink ◽

Pv Systems ◽

Overall Performance

Currently, grid-connected Photovoltaic (PV) systems are widely encouraged to meet increasing energy demands. However, there are many urgent issues to tackle that are associated with PV systems. Among them, partial shading is the most severe issue as it reduces efficiency. To achieve maximum power, PV system utilizes the maximum power point-tracking (MPPT) algorithms. This paper proposed a two-level converter system for optimizing the PV power and injecting that power into the grid network. The boost converter is used to regulate the MPPT algorithm. To make the grid-tied PV system operate under non-uniform weather conditions, dragonfly optimization algorithm (DOA)-based MPPT was put forward and applied due to its ability to trace the global peak and its higher efficiency and shorter response time. Furthermore, in order to validate the overall performance of the proposed technique, comparative analysis of DOA with adaptive cuckoo search optimization (ACSO) algorithm, fruit fly optimization algorithm combined with general regression neural network (FFO-GRNN), improved particle swarm optimization (IPSO), and PSO and Perturb and Observe (P&O) algorithm were presented by using Matlab/Simulink. Subsequently, a voltage source inverter (VSI) was utilized to regulate the active and reactive power injected into the grid with high efficiency and minimum total harmonic distortion (THD). The instantaneous reactive power was adjusted to zero for maintaining the unity power factor. The results obtained through Matlab/Simulink demonstrated that power injected into the grid is approximately constant when using the DOA MPPT algorithm. Hence, the grid-tied PV system’s overall performance under partial shading was found to be highly satisfactory and acceptable.

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Control of power and voltage of solar grid connected

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v6i1.8632 ◽

2016 ◽

Vol 6 (1) ◽

pp. 26 ◽

Cited By ~ 1

Author(s):

Boucetta Abdou Abdallah ◽

Labed Djamel

Keyword(s):

Control Strategy ◽

High Efficiency ◽

Harmonic Distortion ◽

Maximum Power ◽

Photovoltaic System ◽

Pv System ◽

Maximum Power Point ◽

Three Phase ◽

Power Point ◽

Computational Resources

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High Frequency, High Efficiency, and High Power Density GaN-Based LLC Resonant Converter: State-of-the-Art and Perspectives

Applied Sciences ◽

10.3390/app112311350 ◽

2021 ◽

Vol 11 (23) ◽

pp. 11350

Author(s):

Seyed Abolfazl Mortazavizadeh ◽

Simone Palazzo ◽

Arturo Amendola ◽

Enzo De Santis ◽

Dario Di Ruzza ◽

...

Keyword(s):

Power Density ◽

High Power ◽

High Frequency ◽

High Efficiency ◽

Resonant Converters ◽

Switching Frequency ◽

High Power Density ◽

Resonant Converter ◽

Gan Hemt ◽

Llc Resonant Converter

Soft switching for both primary and secondary side devices is available by using LLC converters. This resonant converter is an ideal candidate for today’s high frequency, high efficiency, and high power density applications like adapters, Uninterrupted Power Supplies (UPS), Solid State Transformers (SST), electric vehicle battery chargers, renewable energy systems, servers, and telecom systems. Using Gallium-Nitride (GaN)-based power switches in this converter merits more and more switching frequency, power density, and efficiency. Therefore, the present paper focused on GaN-based LLC resonant converters. The converter structure, operation regions, design steps, and drive system are described precisely. Then its losses are discussed, and the magnets and inductance characteristics are investigated. After that, various interleaved topologies, as a solution to improve power density and decrease current ripples, have been discussed. Also, some challenges and concerns related to GaN-based LLC converters have been reviewed. Commercially available power transistors based on various technologies, i.e., GaN HEMT, Silicon (Si) MOSFET, and Silicon Carbide (SiC) have been compared. Finally, the LLC resonant converter has been simulated by taking advantage of LTspice and GaN HEMT merits, as compared with Si MOSFETs.

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Maximum Power Point Tracking of PV Systems under Partial Shading Conditions Based on Opposition-Based Learning Firefly Algorithm

Sustainability ◽

10.3390/su13052656 ◽

2021 ◽

Vol 13 (5) ◽

pp. 2656

Author(s):

Ahmed G. Abo-Khalil ◽

Walied Alharbi ◽

Abdel-Rahman Al-Qawasmi ◽

Mohammad Alobaid ◽

Ibrahim M. Alarifi

Keyword(s):

Firefly Algorithm ◽

Maximum Power ◽

Pv System ◽

Maximum Power Point ◽

Partial Shading ◽

Point Tracking ◽

Opposition Based Learning ◽

Power Point Tracking ◽

Convergence Process ◽

Power Point

This work presents an alternative to the conventional photovoltaic maximum power point tracking (MPPT) methods, by using an opposition-based learning firefly algorithm (OFA) that improves the performance of the Photovoltaic (PV) system both in the uniform irradiance changes and in partial shading conditions. The firefly algorithm is based on fireflies’ search for food, according to which individuals emit progressively more intense glows as they approach the objective, attracting the other fireflies. Therefore, the simulation of this behavior can be conducted by solving the objective function that is directly proportional to the distance from the desired result. To implement this algorithm in case of partial shading conditions, it was necessary to adjust the Firefly Algorithm (FA) parameters to fit the MPPT application. These parameters have been extensively tested, converging satisfactorily and guaranteeing to extract the global maximum power point (GMPP) in the cases of normal and partial shading conditions analyzed. The precise adjustment of the coefficients was made possible by visualizing the movement of the particles during the convergence process, while opposition-based learning (OBL) was used with FA to accelerate the convergence process by allowing the particle to move in the opposite direction. The proposed algorithm was simulated in the closest possible way to authentic operating conditions, and variable irradiance and partial shading conditions were implemented experimentally for a 60 [W] PV system. A two-stage PV grid-connected system was designed and deployed to validate the proposed algorithm. In addition, a comparison between the performance of the Perturbation and Observation (P&O) method and the proposed method was carried out to prove the effectiveness of this method over the conventional methods in tracking the GMPP.

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