Showing papers on "Power optimizer published in 2018"

Recent progress and development on power DC-DC converter topology, control, design and applications: A review

Abstract: Over the last few decennia, power DC/DC converters have been the subject of great interest due to its extensive increment of utilization in different applications. A thorough review on recent developed power DC/DC converters is presented in this paper. The study is focused on the topologies in different applications such as renewable energy, automobile, high-voltage and medium-voltage DC power systems, telecommunication, etc. In addition, an overview of the modulation techniques, the state-of-the-art of control strategies of well-established converters are discussed. Photovoltaic (PV) systems as the noticeable renewable energy resources generally suffer from poor conversion efficiency with instability and intermittent characteristics. Therefore, DC/DC converter with Maximum Power Point Tracking (MPPT) algorithm is essential to ensure maximum available power harnessed from the PV. Important features of DC/DC converters with MPPT are also figured with various performances. Furthermore, the design and optimization of different parameters are addressed systematically. Finally, the researcher’s future challenges and focusing trends are briefly described. For the next-generation converters design and applications, these are considered in details, and will provide useful framework and point of references.

Application of bio-inspired algorithms in maximum power point tracking for PV systems under partial shading conditions – A review

Abstract: Solar energy is one of the most promising renewable energy resource due to its variety of advantages. The photovoltaic systems have a remarkable development over the past few decades. As the maximum power point of the photovoltaic system varies with the change in environmental conditions, the maximum power point tracking technology is necessary to harvest maximum power from the photovoltaic systems. However, multiple peaks occur in the power-voltage (P-V) curve during partial shading conditions. In such condition, many traditional maximum power point tracking methods like perturbation and observation, and incremental conductance may become invalid due to involvement in the local maximum power point. Many advanced methods based on the artificial intelligence like artificial neural network, and fuzzy logic control can track the global maximum power point. However, they are not feasible in real complex environment because they need massive training and broader experience. Alternatively, bio-inspired maximum power point tracking algorithms deal properly with such situations. In recent years, researchers have widely applied bio-inspired algorithms to track the global maximum power point of photovoltaic system during partial shading situations. This paper presents a comprehensive review of the bio-inspired algorithms used for global maximum power point tracking. Various tracking methods are discussed and compared in terms of their characteristics and corresponding improved methods. It also presents the advantages and disadvantages of each method. The modified and combined forms of these methods found to have better performance than original algorithms. Overall, the performance of swarm intelligence based algorithms is found better than evolutionary algorithms. This review may help the researchers to acquire comprehensive information about the application of bio-inspired algorithms to gain maximum power from the photovoltaic systems, and furthermore, help them to choose an efficient way of global maximum power point tracking in photovoltaic systems during partial shading conditions.

Fault-Tolerant Supervisory Controller for a Hybrid AC/DC Micro-Grid

Abstract: In this paper, a fault-tolerant supervisory controller is proposed for a hybrid ac/dc micro-grid. In the hybrid micro-grid, dc sources, energy storage, and loads are connected to a main dc bus, while the ac sources and sinks are coupled with a main ac bus. A bidirectional converter/inverter exchanges power between both sides. Such structure should be supervised by a main controller or management system. In this approach, the power flow is supervised based on solving an optimization problem, while the maximum available powers for fault-free and erroneous wind, solar, and energy storage sub-systems are taken into account. It is shown that solar and wind sub-system failures affect maximum available powers from those resources. In order to satisfy the demanded power with maximum utilization of renewable resources, the tolerance of the proposed supervisory controller (SC) toward shading and converter faults in the solar system, and lubricant system failure and converter fault in the wind system is considered in the design procedure. Moreover, the tolerance of the proposed power management system toward energy storage failure in each micro-grid is also incorporated in the overall control scheme. Effectiveness of the proposed SC is evaluated through extensive simulation runs based on dynamical models of the power resources.

Benchmarking of Constant Power Generation Strategies for Single-Phase Grid-Connected Photovoltaic Systems

Abstract: With a still increase of grid-connected photovoltaic (PV) systems, challenges have been imposed on the grid due to the continuous injection of a large amount of fluctuating PV power, like overloading the grid infrastructure (e.g., transformers) during peak power production periods. Hence, advanced active power control methods are required. As a cost-effective solution to avoid overloading, a constant power generation (CPG) control scheme by limiting the feed-in power has been introduced into the currently active grid regulations. In order to achieve a CPG operation, this paper presents three CPG strategies based on a power control method (P-CPG), a current limit method (I-CPG), and the perturb and observe algorithm (P&O-CPG). However, the operational mode changes (e.g., from the maximum power point tracking to a CPG operation) will affect the entire system performance. Thus, a benchmarking of the presented CPG strategies is also conducted on a 3-kW single-phase grid-connected PV system. Comparisons reveal that either the P-CPG or I-CPG strategies can achieve fast dynamics and satisfactory steady-state performance. In contrast, the P&O-CPG algorithm is the most suitable solution in terms of high robustness, but it presents poor dynamic performance.

Development of DC to Single-Phase AC Voltage Source Inverter With Active Power Decoupling Based on Flying Capacitor DC/DC Converter

Abstract: In the present, a power decoupling method without additional component is proposed for a dc to single-phase ac converter, which consists of a flying capacitor dc/dc converter (FCC) and the voltage source inverter (VSI). In particular, a small flying capacitor in the FCC is used for both a boost operation and a double-line-frequency power ripple reduction. Thus, the dc-link capacitor value can be minimized in order to avoid the use of a large electrolytic capacitor. In addition, component design, of, e.g., the boost inductor and the flying capacitor, is clarified when the proposed control is applied. Experiments were carried out using a 1.5-kW prototype in order to verify the validity of the proposed control. The experimental results revealed that the use of the proposed control reduced the dc-link voltage ripple by 74.5%, and the total harmonic distortion (THD) of the inverter output current was less than 5%. Moreover, a maximum system efficiency of 95.4% was achieved at a load of 1.1 kW. Finally, the high power density design is evaluated by the Pareto front optimization. The power densities of three power decoupling topologies, such as a boost topology, a buck topology, and the proposed topology are compared. As a result, the proposed topology achieves the highest power density (5.3 kW/dm3) among the topologies considered herein.

Performance of Interconnection Protection Based on Distance Relaying for Wind Power Distributed Generation

Abstract: This paper proposes a method to analyze and improve the performance of interconnection protection based on distance relaying for wind power distributed generation (DG) in distribution systems. Of particular importance is distance protection that uses the concept of prefault voltages as reference quantities found to have issues with intermittent behavior of wind power DG. This concept is normally used in different distance protective relaying applications in order to increase the fault resistance coverage capability of the distance relays as well as to ensure selectivity, dependability, and security under extreme undervoltages. The main contributions of this paper are to analyze this issue and propose a method to enhance the performance of distance protection to mitigate this issue. In this methodology, several case studies are investigated with different penetration levels, weather patterns, and configuration topology of DGs under both normal operating conditions as well as fault conditions. Results for a case study are given.

Fault Ride-Through Enhancement for Grid-Tied PV Systems With Robust Control

Abstract: In this paper, a new control structure is proposed for grid-tied photovoltaic (PV) systems where the dc bus voltage is regulated by the dc/dc converter controller, whereas the maximum power point tracking (MPPT) function and the power flow control are embedded into the dc/ac converter controller. A PV voltage-regulation is designed to build the linkage between MPPT function and power flow control. In this way, the dc/dc converter controller and the dc/ac converter controller are decoupled, which naturally provides the dc bus voltage protection. In particular, an uncertainty and disturbance estimator (UDE)-based current-mode controller (CMC) is proposed for accurate voltage regulation of the dc/dc converter. And a bounded-voltage power flow control strategy is proposed for the dc/ac converter to improve the existing UDE-based robust power flow control for ac voltage protection. The effectiveness of the proposed method is experimentally validated in a lab-environment grid-tied PV system platform with the fault ride-through capabilities. In addition, simulation studies are also provided to demonstrate the need of the PV voltage-regulation between MPPT and power flow control, and the advantages of the bounded-voltage design in the power flow control.

Maximum Power Point Tracking and Output Power Control on Pressure Coupling Wind Energy Conversion System

Abstract: This paper proposed a combined method for wind energy conversion system using pressure coupling (PC) hydrostatic transmission. The operation strategy is the combination of maximizing power point tracking at the input power and stabilizing the output power. The maximum power point tracking method is to control the turbine speed for tracking the optimal tip speed ratio (TSR). For maximizing the input power, a PID controller and a sliding mode controller are applied for speed control to track a predefined speed that is calculated from the optimal TSR. The output power is stabilized by using a high-pressure accumulator for accumulating and compensating the power. The driven speed of the generator is controlled by the PC principle, using a PID controller and an adaptive fuzzy sliding mode controller. Experiments are carried out to verify the proposed method. The overall efficiency in several wind speed profiles is about 40%.

Adaptive Fault-Tolerant Control of Wind Turbines With Guaranteed Transient Performance Considering Active Power Control of Wind Farms

Abstract: As high-order nonlinear large-scale systems, wind farms composed of multiple wind turbines (WTs) need to adopt active power control (APC) to track the power set points, rather than the maximum power points. In this paper, the proportional distribution strategy is utilized to specify the power set point according to the available output power of each WT based on the ultra-short-term wind speed prediction. Then, we convert the APC problem into the rotor speed tracking control problem, and a robust adaptive fault-tolerant control approach based on the barrier Lyapunov function is developed to track the desired power signal of each WT with guaranteed transient performance and robustness to actuator faults. The effectiveness and the merit of the proposed approach are validated by applying it to the APC of a wind farm.

A Fully Parallel Stochastic Multiarea Power System Operation Considering Large-Scale Wind Power Integration

Abstract: Multiarea power system operation/coordination is used to increase the reliability of the interconnected power grids and maintain the consistency of the price across the integrated power systems. However, the implementation of this coordinated operation is facing challenges due to increase in size and complexity of the modern power systems, high penetration of the volatile renewable energy, and interdependence issues among various power systems. To address these concerns, this paper presents a fully parallel decision-making approach for the day-ahead scheduling of interconnected power systems with large-scale wind power integration while respecting the information privacy between different systems/areas. In the proposed parallel approach, each system/area solves its day-ahead scheduling problem along with its local subproblems for different wind generations’ scenarios, and sends its equivalent (or processed) boundary information to other systems/areas. The proposed inter-regional coordination among systems/areas and intra-regional coordination between scenarios in each system/area will continue until the tie-line power flows and the generation outputs of generating units get converged. The modified IEEE 118-bus testing system is used in this paper to show the effectiveness of the proposed approach.

Analysis of a High-Power, Resonant DC–DC Converter for DC Wind Turbines

Abstract: This paper is introducing a new method of operation for a series resonant converter, with intended application in megawatt high-voltage dc wind turbines. Compared to a frequency controlled series resonant converter operated in subresonant mode, the method (entitled pulse removal technique) allows the design of the medium frequency transformer for highest switching frequency, while being operated at lower frequency without saturation. The main focus of this paper is to identify and analyze the operating modes of the converter with pulse removal technique. With the use of variable frequency and variable phase displacement in subresonant mode, the new method of operation promises transformer size reduction and facilitates soft-switching transition of the insulated gate bipolar transistors (IGBTs) and line frequency diodes on rectifier side. Four modes of operation are identified, while equations for output power, voltage, and current stress are identified. Experimental results are concluded on a 1 kW, 250 V/500 V prototype.

Optimal Derating Strategy of Power Electronics Converter for Maximum Wind Energy Production with Lifetime Information of Power Devices

Abstract: One of the most important causes of failure in wind power systems is due to the failures of the power converter and due to one of its most critical components, the power semiconductor devices. This paper proposes a novel derating strategy for the wind turbine system based on the reliability performance of the converter and the total energy production throughout its entire lifetime. An advanced reliability design tool is first established and demonstrated, in which the wind power system together with the thermal cycling of the power semiconductor devices are modeled and characterized under a typical wind turbine system mission profile. Based on the reliability design tools, the expected lifetime of the converter for a given mission profile can be quantified under different output power levels, and an optimization algorithm can be applied to extract the starting point and the amount of converter power derating which is necessary in order to obtain the target lifetime requirement with a maximum energy production capability. A nonlinear optimization algorithm has been implemented and various case studies of lifetime requirements have been analyzed. Finally, an optimized derating strategy for the wind turbine system has been designed and its impact has been highlighted.

Analysis of DC-Link Current Influence on Temperature Variation of Capacitor in a Wind Turbine Application

Abstract: Back-to-back converters for wind turbine systems feature capacitors in the dc-link to maintain a stable voltage and to decouple a generator from the electric grid The electrolytic capacitors are typically chosen for their advantages; a higher energy density and a higher capacitance at lower costs Long-term field experiences and recorded failure data revealed that the capacitors are one of the most frequent failure reasons for the wind turbine system The current profile of the capacitors is highly responsible for this degradation, since it determines the dissipated power of the capacitor This paper analyzes the actual current profile in the dc-link capacitor of a back-to-back converter for wind turbine application A power converter is also designed to generate sinusoidal current at arbitrary frequency and arbitrary dc bias voltage for testing purposes The experimental results confirm that the proposed power converter enables us to derive the correlation between the current frequency and the temperature variation of capacitor

Optimal control of a wind turbine with digital fluid power transmission

Abstract: Digital fluid power (DFP) technology may lead to a paradigm shift in large-scale transmission systems in, e.g., wind and wave energy. Therefore, the development of applicable control algorithms is of major importance, but is complicated by the non-smooth behavior of the DFP displacement machines. The power throughput of a full stroke operated digital displacement machine is quantized by the number of pressure chambers. The dynamics of each pressure chamber may be described by highly nonlinear continuous differential equations, whereas the input is discretely updated and binary (active or inactive). This paper contributes with a feedback control strategy for a digital displacement machine, where the binary inputs are handled by a pulse density modulator. The paper presents a linearization method of handling the many nonlinearities and thereby enabling the use of Discrete Linear Time Invariant (DLTI) control theory. The control strategy is validated for control of a digital fluid power wind turbine transmission, where both a deterministic and a stochastic optimal controllers are synthesized. The study is based on the NREL 5-MW reference wind turbine, where its model is combined with a nonlinear model of the DFP transmission and full-field flow wind profiles are used for a realistic performance evaluation scenario. By simulation, it is found that the performance of the optimal controllers using the DFP transmission is similar to that of the NREL controller using a conventional transmission.

Sequence Domain Harmonic Modeling of Type-IV Wind Turbines

Abstract: A sequence domain (SD) harmonic model of a grid-connected voltage-source converter is developed for decoupling converter generated voltage harmonics from voltage harmonics in the external grid. The modeling procedure includes a derivation of the baseband frequency response for regular-sampled pulse width modulation and an analysis of converter generated voltage harmonics due to compensated dead-time. The decoupling capabilities of the proposed the SD harmonic model are verified through a power quality (PQ) assessment of a 3 MW Type-IV wind turbine. The assessment shows that the magnitude and phase of low-order odd converter generated voltage harmonics are dependent on the converter operating point and the phase of the fundamental component of converter current, respectively. The SD harmonic model can be used to make PQ assessments of Type-IV wind turbines or incorporated into harmonic load flows for computation of PQ in wind power plants.

A Simple Open-Circuit Detection Strategy for a Single-Phase Grid-Connected PV Inverter Fed From Power Optimizers

Abstract: A simple and real-time open-circuit fault (OCF) detection method is proposed for a single-phase grid-connected photovoltaic inverter fed by series-connected power optimizers (POs). To implement the proposed method, PO controllers periodically monitor POs’ output voltage variations and calculate output voltage residual errors. Then, on the PO side, the OCF identification rule for the inverter is developed, which is based on the amount of voltage variation and the improved judgment criterion derived from voltage residual error and power. The proposed OCF detection method is of low cost and is real time, needing no extra hardware and no communication between the inverter and POs. Generally speaking, the method provides a reliable and fast solution to detect OCFs in the series-connected distributed dc power or energy storage systems. Its effectiveness and reliability are verified by experimental results.

A High-Power, Medium-Voltage, Series-Resonant Converter for DC Wind Turbines

Abstract: A new modulation scheme is introduced for a single-phase series-resonant converter, which permits continuous regulation of power from nominal level to zero, in presence of variable input and output dc voltage levels. Rearranging the circuit to locate the resonant LC tank on the rectifier side of the high turns-ratio transformer combined with frequency control and phase-shifted inverter modulation keep transformer flux constant from nominal frequency down to dc, always in subresonant continuous or discontinuous conduction mode. This overcomes the principal deficit of series-resonant converters, and the resulting compact and efficient transformer, and soft-commutated inverter, present particular advantages in high-power, high-voltage applications, such as dc offshore wind turbines. With transformer excitation frequency in hundreds of Hz range, line-frequency diodes can be employed in the high-voltage rectifier valve. Circuit operation and conduction modes, governing equations, and sample waveforms are presented, together with experiments from a scaled demonstrator.

Control of Grid Connected Photovoltaic Systems with Microinverters: New Theoretical Design and Numerical Evaluation

Abstract: This paper addresses the problem of controlling grid connected photovoltaic (PV) systems that are driven with microinverters. The systems to be controlled consist of a solar panel, a boost dc–dc converter, a DC link capacitor, a single-phase full-bridge inverter, a filter inductor, and an isolation transformer. We seek controllers that are able to simultaneously achieve four control objectives, namely: (i) asymptotic stability of the closed loop control system; (ii) maximum power point tracking (MPPT) of the PV module; (iii) tight regulation of the DC bus voltage; and (iv) unity power factor (PF) in the grid. To achieve these objectives, a new multiloop nonlinear controller is designed using the backstepping design technique. A key feature of the control design is that it relies on an averaged nonlinear system model accounting, on the one hand, for the nonlinear dynamics of the underlying boost converter and inverter and, on the other, for the nonlinear characteristic of the PV panel. To achieve the MPPT objective, a power optimizer is designed that computes online the optimal PV panel voltage used as a reference signal by the PV voltage regulator. It is formally shown that the proposed controller meets all the objectives. This theoretical result is confirmed by numerical simulation tests.

Real-time implementation of a maximum power point tracking algorithm based on first order sliding mode strategy for photovoltaic power systems:

Abstract: This paper focuses on a maximum power point tracking (MPPT) algorithm based on the first order sliding mode approach. This work is aimed at systems that are fed with a photovoltaic (PV) generator. ...

Evaluation of a Distributed Photovoltaic System in Grid-Connected and Standalone Applications by Different MPPT Algorithms

Abstract: Due to the shortage of fossil fuel and the environmental pollution problem, solar energy applications have drawn a lot of attention worldwide. This paper reports the use of the latest patented distributed photovoltaic (PV) power system design, including the two possible maximum power point tracking (MPPT) algorithms, a power optimizer, and a PV power controller, in grid-connected and standalone applications. A distributed PV system with four amorphous silicon thin-film solar panels is used to evaluate both the quadratic maximization (QM) and the Steepest descent (SD) MPPT algorithms. The system’s design is different for the QM or the SD MPPT algorithm being used. The test result for the grid-connected silicon-based PV panels will also be reported. Considering the settling time for the power optimizer to be 20 ms, the test result shows that the tracking time for the QM method is close to 200 ms, which is faster when compared with the SD method whose tracking time is 500 ms. Besides this, the use of the QM method provides a more stable power output since the tracking is restricted by a local power optimizer rather than the global tracking the SD method uses. For a standalone PV application, a solar-powered boat design with 18 PV panels using a cascaded MPPT controller is introduced, and it provides flexibility in system design and the effective use of photovoltaic energy.

Distributed multi-agent control for combined AC/DC grids with wind power plant clusters

Abstract: The combined AC/DC grids have, due to their technological features of high voltage and large capacity as well as operating flexibility and reliability, become one of the most potential solutions to connect large-scale wind farms to power systems. The traditional centralised control lacks flexibility and robustness. In contrast, the distributed control is unable to simultaneously consider global optimum and response speed. A scheme of intelligent distributed control for combined AC/DC grids is proposed to constitute a multi-agent system by equipping each terminal with an agent. While adopting the proposed control method, the optimisation of the upper layer is similar to the traditional grid dispatch and the lower layer system achieves the group compromise through the interaction and coordination among the agents and between the agents and the system. Based on the state information such as the voltage and the frequency of the neighbouring converter stations, the combined AC/DC grids can allocate the active power reasonably through the consistency control and provide the frequency support of the AC grid. Finally, four operating scenarios, including wind speed jump, wind power plant cluster disconnection, converter station failure and load demand response, are verified in a typical model of combined AC/DC grids by using the PSCAD/EMTDC software.

Solar-powered boat design using standalone distributed PV system

Abstract: Due to the shortage for fossil fuel and the environmental pollution problem, renewable energy application has drawn a lot of attention worldwide. Utilization of photovoltaic energy for public open-water activity becomes possible, thanks to the success of the Planet Solar project. However, an economic solution to deploy the PV power system onto an electric boat has not been reported. This paper presents a solar-powered boat design using the latest patented distributed PV power system which includes the state-of-the-art maximum power point tracking technology, power optimizer and the PV power controller. Distributed PV system with more than 10 PV panels using cascaded MPPT controller provides the flexibility of system design and the effective use of photovoltaic energy. The system has been realized by remodeling a PV boat cruising at Love River, Kaohsiung City, Taiwan. Design details will be reported, and its efficiency will also be addressed.

An Efficient PV Power Optimizer With Reduced EMI Effects: Map-Based Analysis and Design Technique

Abstract: The aim of this paper is to develop a one-dimensional (1-D) discrete-time model or map that will ensure reliable and safe chaotic operation of a modular photovoltaic (PV) power optimizer (PO) system. Based on this 1-D map, we perform the detailed bifurcation analysis and discuss a preliminary design guideline to operate the system into a desired chaotic regime, i.e., just after the golden mean. We show that operating POs in chaotic regime cannot only yield broader power spectrum with reduced spectral peak at the switching frequency harmonics of the system, but also exhibits faster tracking responses with overall conversion efficiency $\eta \geq$ 98%. Moreover, this optimized frequency-domain as well as time-domain performance are numerically analyzed and then verified experimentally using a prototype modular boost-type PV system.

Power Electronic Modules

Abstract: A power electronic module or power module is an assembly containing several power components, mostly power semiconductor devices, properly internally interconnected to perform a power conversion function. It is an integrated building block for the realization of a power converter with a reduced number of external components required. Control electronics such as gate drivers, sensing, and protection functions may be included inside the power module package. In this case, the term intelligent power module is commonly used. From the electric standpoint, the power module reduces parasitic elements in the interconnection of the power semiconductor devices due to the tight physical integration. From the thermal standpoint, the power module usually has a thermally conductive baseplate that can be bolted to a heat sink or a cold plate to remove the loss heat generated as a result of power converter operation. From the mechanical standpoint, it provides a robust mechanical package for the power components inside. In conclusion, a power module is an electro-thermo-mechanical device optimized for power converter operation. Using a power module may simplify the design of a power converter because the power module design provides a robust mechanical structure and guarantees proper operation from an electric and thermal point of view as long as the module datasheet specifications and guidelines are followed. Power modules are typically used at higher power levels, where a discrete component implementation would require paralleling of several power semiconductor devices.

A Step-Down Partial Power Optimizer Structure for Photovoltaic Series-Connected Power Optimizer System

Abstract: This paper proposed a step-down partial-power optimizer (PPO) structure to realize the Maximum Power Point Tracking (MPPT) for PV series-connected optimizer system. In the traditional power optimizer, the whole amount of PV panel power is processed by the converter, whereas in a partial-power optimizer only a fraction of the full panel power is processed. Therefore, the size and cost of the power optimizer are decreased. The proposed PPO structure is a buck structure, which mainly consists of an isolated DC/DC converter. Comparing with the boost structure, the buck structure can allow more PV panels and more importantly, the buck converter can operate normally even when bad partial shading occurs. A simulation and a hardware platform are built to verify the proposed PPO structure. The result shows good tracking accuracy and high efficiency of MPPT.

Potential of Wind Farms Connected to HVdc Grid to Provide DC Ancillary Services

Abstract: DC grids will require ancillary services to compensate for uncertainties, such as disturbances and converter outages. The appropriate equipment behavior and the sources of these services consequently need to be defined. This paper describes the reaction, activation, and provision intervals of ancillary services for dc grids to maintain the dc voltage in a certain range. It also discusses how wind power plants and synchronous generators that are exclusively connected to a dc grid can comply with these requirements. The theoretical descriptions are validated using simulations.

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

Abstract: 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.

Implementation of modified P&O method as power optimizer of solar panel under partial shading condition for battery charging system

Abstract: Photovoltaic (PV) module is used to convert solar energy to electrical energy. The output power of PV module is affected by the amount of irradiation of sun and temperature of PV module. The problem that may occur is partial shading caused by some objects such as trees, building, clouds, and so on. The impact of this condition is the decrease of output power of PV and the maximum power point (MPP) become more than one. Maximum power point of P-V characteristic curve will be more than one such as GMPP (Global Maximum Power Point) and LMPP (Local Maximum Power Point). This case cannot be solved using the ordinary MPPT (Maximum Power Point Tracking) method because the maximum power is trapped on wrong point, it is LMPP. Therefore, to overcome this problem, Modified P&O (Perturb and Observe) method is proposed as a MPPT method under partial shading condition. The proposed method is implemented on SEPIC converter to get actual maximum power point (GMPP). Experiment results prove the Modified P&O method can generate greater power and faster charging process on battery. The State of Charge of battery increases about 30% if the Modified P&O method, which is applied on battery charging system.Photovoltaic (PV) module is used to convert solar energy to electrical energy. The output power of PV module is affected by the amount of irradiation of sun and temperature of PV module. The problem that may occur is partial shading caused by some objects such as trees, building, clouds, and so on. The impact of this condition is the decrease of output power of PV and the maximum power point (MPP) become more than one. Maximum power point of P-V characteristic curve will be more than one such as GMPP (Global Maximum Power Point) and LMPP (Local Maximum Power Point). This case cannot be solved using the ordinary MPPT (Maximum Power Point Tracking) method because the maximum power is trapped on wrong point, it is LMPP. Therefore, to overcome this problem, Modified P&O (Perturb and Observe) method is proposed as a MPPT method under partial shading condition. The proposed method is implemented on SEPIC converter to get actual maximum power point (GMPP). Experiment results prove the Modified P&O method can gen...

Modelling and Simulation of Grid Connected SPV System with Active Power Filtering Features

Abstract: In this paper, the detailed simulation studies for a grid connected solar photovoltaic system (SPV) have been presented The power electronics devices like DC–DC boost converter and grid interfacing inverter are most important components of proposed system Here, the DC–DC boost converter is controlled to extract maximum power out of SPV under different irradiation levels, while the grid interfacing inverter is utilized to evacuate the active power and feed it into grid at synchronized voltage and frequency Moreover, the grid interfacing inverter is also controlled to sort out the issues related to power quality by compensating the reactive power and harmonics current component of nearby load at point of common coupling Besides, detailed modeling of various component utilized in proposed system is also presented Finally, extensive simulations have been performed under different irradiation levels with various kinds of load to validate the aforementioned claims The overall system design and simulation have been performed by using Sim Power System toolbox available in the library of MATLAB