EPE Association: EPE 2015 - DS3g: Solar Energy Systems

EPE 2015 - DS3g: Solar Energy Systems
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2015 ECCE Europe - Conference > EPE 2015 - Topic 05: Renewable Energy Power Systems > EPE 2015 - DS3g: Solar Energy Systems

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   A Low Leakage Transformer-less 3-Level DC-DC Boost Converter for Transformer-less PV Inverters
By Rajesh Singh FARSWAN [View]
[Download]

Abstract: In this paper a modification for a conventional 3-level DC-DC buck-boost converter is proposed for photovoltaic applications, to eliminate the problem of leakage current which is associated with this converter. With this modification it is possible to interface the proposed transformer-less converter with transformer-less PV inverters without any galvanic isolation requirement from the grid. This transformer-less converter is also suitable to interface PV source with grounded DC micro-grids. The proposed converter has low leakage current and retains the advantage of high efficiency due to its lower voltage stress on switching devices, which is similar to conventional 3-level DC-DC converter. Common mode voltage analysis and simulation is done to verify the proposed topology. The proposed scheme is verified on a laboratory prototype and the results are provided.

   A Novel Adaptive Magnetizing Inductance Control Scheme for High-Efficiency LLC Resonant Converter for PV applications
By Ki-hyeon PARK [View]
[Download]

Abstract: In this paper, A novel control scheme of LLC resonant converter is proposed to maximize energyharvest of photovoltaic resources by adapting an integrated transformer with variable magnetizinginductance adaptively. The proposed resonant converter changes its magnetizing inductance accordingto the PV panel operating condition, and thus it is possible to achieve a minimum circulating energyunder wide input voltage range by the appropriate DC gain of the resonant tank. In addition, theproposed method introduces the feedback loop based on the switching frequency to regulate themagnetizing inductance, and as a result, those advantages can be easily obtained in even wide outputpower levels. The operating principles of the proposed converter and its control structure are explainedin detail, and the design example of a 250-W converter is also presented by using the fundamentalharmonic analysis. Several simulation results under various conditions of PV source and output powerlevels are provided in order to verify its effectiveness.

   A TOOL FOR THE PERFORMANCE EVALUATION AND FAILURE DETECTION OF AMARALEJA PV PLANT (ACCIONA) FROM SCADA
By MIKEL MUÑOZ [View]
[Download]

Abstract: This paper describes a tool developed for the performance evaluation and failure detection in a 45.6 MWp PV plant installed by the company Acciona in Amareleja (Portugal). The paper describes the PV plant configuration and its SCADA (Supervisory Control And Data Acquisition), the measured variables and the main functionalities of the software. Some of these functionalities are the automatic and accurate PSTC (Power under standard test conditions ) calculation for each generator and for the whole PV Plant, the reference production that would be delivered by the PV plant assuming a 100\% availability, the hierarchy of SCADA alarms, the detection of long-term trends and degradation in PV generators, possible hidden problems in the different equipment and systems composing the PV plant, etc.This tool entered into operation in 2011 and is working properly since then.

   Analysis of a Flyback Current Source Inverter under Hybrid DCM-BCM operation
By Georgios CHRISTIDIS [View]
[Download]

Abstract: The Current-Source Flyback micro-inverter is widely used in ac-PV module applications, operated either on Discontinuous Conduction Mode (DCM) or Boundary Conduction Mode (BCM). However, each mode has its performance disadvantages (either low power density for DCM or low efficiency due to increased switching losses for BCM). To overcome the above, a hybrid DBCM operation is proposed hereafter, taking into consideration that a smooth transition between the two operating modes needs to be achieved in order to have good output power quality. The mathematical analysis for the hybrid operating mode is presented and validated through simulation and experimental results.

   ANN-Based Extraction Approach of PV Cell Equivalent Circuit Parameters
By Adel GASTLI [View]
[Download]

Abstract: In most practical cases, a PV array is constructed from a combination of standard PV units (solar cells or panels) connected in series and/or in parallel to obtain the desired power, voltage and current ratings. However, the non-linear behavior of solar cells or panels makes accurate determination of the model parameters a difficult task. A precise determination of the internal physical parameters of cells and panels is not always possible because of the non-uniqueness of the solution. As a result, some parameters of the PV panel model are estimated with non-negligible errors. In this paper, an advanced ANN-based determination approach of PV array parameters from individual cell/panel characteristics is developed for single-diode model. A proper selection of the training points for the ANN is also introduced to improve the estimation of the model. Simulation results obtained for simple case studies using Matlab/Simulink software are presented and discussed. The proposed ANN-based technique made possible more accurate determination of the parameters of the single-diode model with mean errors below 1\% for all parameters except for the diode saturation and diffusion current which reached 11\%.

   Applying Fault Ride Through Capability to Single Phase Grid Connected PV Systems
By IOANNIS PERPINIAS [View]
[Download]

Abstract: The grid-tied low voltage photovoltaics are expanded day by day. Aiming for a high penetration level, the Fault Ride Through Capability (FRTC) standard should be extended to these units as well. In this paper, the behavior of Single Phase Grid Connected PV Systems under faulty conditions is investigated. For this purpose, a SPWM controlled full bridge voltage source inverter is used. The proposed control concept emerges from the conventional synchronous generator behavior during faults. In this way, the low voltage distributed PV Systems can contribute during faults with currents quite higher than their nominal ones, serving the FRTC demands by injecting reactive power amounts. However, in case of excessive inverter faulty currents, current limiters are enabled. The introduced control is validated by simulation results, emphasizing at the transient interval between the fault occurrence and the steady-state faulty situation. Furthermore, the impact of the inverter's equivalent impedance is investigated, regarding the inverter's current and the resulting active and reactive power injection.

   Cascaded H-bridge control for PV application
By JAYANTI GANESH [View]
[Download]

Abstract: In this paper, application of a cascaded H-bridge (CHB) converter to connect strings of solar panels to a single-phase medium voltage AC grid is discussed. With solar insolation levels differing from one string to another, it is challenging to control a CHB converter in order to minimize the variations in the dc link voltages of each of the converter modules and hence the device voltage stress levels. To minimize the device voltage stresses, in this paper, a new Maximum Power Point Tracking (MPPT) method is proposed. The proposed method equalizes the power drawn from each of the solar strings connected to the CHB across a large geographical area (e.g. along a railway line) and avoids excess device stresses. The proposed MPPT method is verified using simulation results.

   Comparison of continuous and transition mode in a PV-booster with GaN-transistors and switching frequencies up to 250 kHz
By David DERIX [View]
[Download]

Abstract: A 1.8 kW boost converter for a PV-inverter with a switching frequency up to 250 kHz is analyzed.The boost converter consists of two parallel legs and the hardware is built so that chokes andsemiconductors can be exchanged easily. Two different operating modes, the Continuous InductionCurrent Mode (CICM) with a fixed switching frequency of fS = 250 kHz and the Transition Mode(TM) with a variable switching frequency are compared. The basic operation principles are explainedand efficiency measurements on real hardware under different conditions (output power,semiconductors (GaN/Si)) are shown. An improved version of the Transition Mode is developedwhich leads to higher efficiencies. Exceptional efficiencies of _max,CICM = 98.2 \% in CICM atfS = 250 kHz and _max,eTM = 98.7 \% in enhanced TM are obtained.

   Fault Ride Through Control by using New Real Time Symmetrical Coordinate Transformation
By Xiaoxiao YU [View]
[Download]

Abstract: This paper proposes a real time symmetrical coordinate transformation applied for detection of imbalanced fault in utility power system. The power conditioner of the photovoltaic system in Japan is required to remain connected when the utility power system fault occurs under certain condition. The most popular fault is 1 line-to-ground fault. The next is 2 line-short fault. Both cause the imbalance voltages and currents in 3-phase power system. To optimize the output from the power conditioner of the photovoltaic system, the detection of the imbalanced condition is important factor. In this paper, new development of the signal processing method by using the complex number algebra in real time system is shown. The fast detection of the imbalanced condition is verified by the computer simulations.

   Input-Voltage Sliding Mode Control for Improving Energy Harvesting of Grid-Connected PV Inverters
By SHUO YAN [View]
[Download]

Abstract: In this paper, we propose the use of sliding mode (SM) control to improve the maximum power point tracking (MPPT) performance of a two-stage single-phase inverter (comprising a first-stage DC/DC boost converter and a second-stage full-bridge inverter) in photovoltaic (PV) systems. To underscore the benefits of SM control, the MPPT performance of the PV system under the SM control is compared to that of an optimally-tuned proportional-integral (PI) control under the same PV system setup. To ease the comparison, a methodology of quantifying the measurements, which provides a clear graphical indication of the quality of the tracking, is proposed as a general platform to examine the performance. Experimental results show that the SM control can guarantee a better tracking accuracy over a larger operating range than the PI control when the weather conditions are changed dynamically throughout the course of a day. Additional comparisons based on the proposed methodology further supports that the SM control can improve the MPPT accuracy of the PV system, thus increasing the overall amount of energy harvested.

   Low Power Interleaved DC-DC Converter with High Voltage Gain for Photovoltaic Applications
By António MARTINS [View]
[Download]

Abstract: Before being injected into the electric grid, the energy provided by a photovoltaic panel must be conditioned in several stages. In the micro-inverter concept, the low voltage at the output of a panel is elevated using a DC-DC converter, being the power controlled by a maximum power point tracking algorithm in such a way that the panel always works around its maximum power point. The paper presents the design and implementation of a DC-DC converter based on the three-state switching cell and voltage multipliers. The converter can be easily integrated in low-power photovoltaic applications due to its high voltage conversion ratio, high efficiency and power density. The main design parameters are discussed and a precise converter model is presented. Simulation and experimental results for an extended input voltage range show the validity of the design approach and the suitability of the converter for micro-inverterapplications.

   Phase Shifted Maximum Power Point Tracking in a Cascaded H-Bridge Photovoltaic System
By Nathan MARKS [View]
[Download]

Abstract: Multilevel Cascaded H-Bridge (CHB) converters have attractive features for the implementation of largescale photovoltaic systems. They can be directly connected to high voltages and the multilevel voltagesynthesis reduces the harmonic distortion introduced. In addition, they have individual DC links ideal forconnecting photovoltaic arrays. Existing high performance voltage balancing techniques can also be adaptedto integrate Maximum Power Point Tracking (MPPT). This paper considers the impact of Perturb and Ob-serve Maximum Power Point Tracking on the performance of a 19 level three phase CHB converter andproposes the new method of Phase Shifted Perturb and Observe Maximum Power Point Tracking.

   PWM Converter Integrating Switched Capacitor Voltage Equalizer for Photovoltaic Modules under Partial Shading
By Masatoshi UNO [View]
[Download]

Abstract: Various kinds of voltage equalizers have been proposed in order to preclude negative impacts of partial shading issues in photovoltaic (PV) systems. However, in addition to a converter to control a PV string, a voltage equalizer needs to be installed in a PV system, increasing the system complexity and cost. In this paper, a PWM converter integrating a switched capacitor (SC) voltage equalizer for PV modules under partial shading is proposed. A PWM converter and SC voltage equalizer can be integrated into a single unit without increasing the component count, achieving the system- and circuit-level simplification. The proposed integrated converter is compared with a conventional system using a converter and equalizer separately, from various aspects, such as voltage step-down ratio, total device power rating (TDPR) and converter size metrics. Furthermore, a dc equivalent circuit of the integrated converter, which can dramatically reduce simulation burden and time, is derived. Experimental tests using a 100-W prototype were performed for three modules connected in series under an emulated shading condition. The extractable maximum power from the string was dramatically increased by preventing the partial shading issues while the generated power from the string was transferred to the load, demonstrating the efficacy of the proposed integrated converter.

   Quantified Evaluation and Criteria Analysis for Distributed MPPT PV System
By Feng WANG [View]
[Download]

Abstract: Distributed Maximum Power Point Tracking (DMPPT) concept provides effective anti-mismatchfeature, however, it fails in extreme mismatch situation. To get full profit from PV system,quantitatively static analyzes of major DMPPT structures are presented. The existence criteria andquantitative evaluation method for optimal power region of different DMPPT structures are firstproposed. Simulation and experimental case study are provided to prove the effectiveness of theproposal.

   Repetitive Control of Flyback Inverter for PV Power Applications
By Sungho LEE [View]
[Download]

Abstract: In this paper, a repetitive controller (RC) is proposed for flyback inverter operating in continuous conduction mode, which has simple structure, low cost, and high efficiency. Conventional controller results in poor control performance due to the effect of the right-half-plane zero in CCM operation. To achieve the fast dynamical response, the repetitive controller is developed and applied to flyback inverter in CCM operation. In RC scheme, a low-pass filter is adopted in the repetitive control scheme to enhance the robustness of repetitive controller. The stability of closed-loop system is derived and the zero tracking error is achieved. Numerical simulations and experiments are performed to validate the proposed control approach.

   SysML Methodology for HiL Implementation of PV Models
By Harold CHAMORRO [View]
[Download]

Abstract: This paper describes a methodology for implementing in FPGA models of photovoltaic panels for Hardware in-the-Loop (HIL) and real-time simulations. The proposed methodology integrates numerical solutions, SysML diagrams and Petri nets for structural design and formal validation. In this study, photovoltaic cells have been modeled using the single diode circuit. The photovoltaic panel model is solved by the Newton-Raphson method, and the Lagrange remainder is employed to limit the iteration number. Results show suitable accuracy and performance of the proposed methodology.

EPE 2015 - DS3g: Solar Energy Systems
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2015 ECCE Europe - Conference > EPE 2015 - Topic 05: Renewable Energy Power Systems > EPE 2015 - DS3g: Solar Energy Systems
	[return to parent folder]

	A Low Leakage Transformer-less 3-Level DC-DC Boost Converter for Transformer-less PV Inverters By Rajesh Singh FARSWAN	[View] [Download]
Abstract: In this paper a modification for a conventional 3-level DC-DC buck-boost converter is proposed for photovoltaic applications, to eliminate the problem of leakage current which is associated with this converter. With this modification it is possible to interface the proposed transformer-less converter with transformer-less PV inverters without any galvanic isolation requirement from the grid. This transformer-less converter is also suitable to interface PV source with grounded DC micro-grids. The proposed converter has low leakage current and retains the advantage of high efficiency due to its lower voltage stress on switching devices, which is similar to conventional 3-level DC-DC converter. Common mode voltage analysis and simulation is done to verify the proposed topology. The proposed scheme is verified on a laboratory prototype and the results are provided.

	A Novel Adaptive Magnetizing Inductance Control Scheme for High-Efficiency LLC Resonant Converter for PV applications By Ki-hyeon PARK	[View] [Download]
Abstract: In this paper, A novel control scheme of LLC resonant converter is proposed to maximize energyharvest of photovoltaic resources by adapting an integrated transformer with variable magnetizinginductance adaptively. The proposed resonant converter changes its magnetizing inductance accordingto the PV panel operating condition, and thus it is possible to achieve a minimum circulating energyunder wide input voltage range by the appropriate DC gain of the resonant tank. In addition, theproposed method introduces the feedback loop based on the switching frequency to regulate themagnetizing inductance, and as a result, those advantages can be easily obtained in even wide outputpower levels. The operating principles of the proposed converter and its control structure are explainedin detail, and the design example of a 250-W converter is also presented by using the fundamentalharmonic analysis. Several simulation results under various conditions of PV source and output powerlevels are provided in order to verify its effectiveness.

	A TOOL FOR THE PERFORMANCE EVALUATION AND FAILURE DETECTION OF AMARALEJA PV PLANT (ACCIONA) FROM SCADA By MIKEL MUÑOZ	[View] [Download]
Abstract: This paper describes a tool developed for the performance evaluation and failure detection in a 45.6 MWp PV plant installed by the company Acciona in Amareleja (Portugal). The paper describes the PV plant configuration and its SCADA (Supervisory Control And Data Acquisition), the measured variables and the main functionalities of the software. Some of these functionalities are the automatic and accurate PSTC (Power under standard test conditions ) calculation for each generator and for the whole PV Plant, the reference production that would be delivered by the PV plant assuming a 100\% availability, the hierarchy of SCADA alarms, the detection of long-term trends and degradation in PV generators, possible hidden problems in the different equipment and systems composing the PV plant, etc.This tool entered into operation in 2011 and is working properly since then.

	Analysis of a Flyback Current Source Inverter under Hybrid DCM-BCM operation By Georgios CHRISTIDIS	[View] [Download]
Abstract: The Current-Source Flyback micro-inverter is widely used in ac-PV module applications, operated either on Discontinuous Conduction Mode (DCM) or Boundary Conduction Mode (BCM). However, each mode has its performance disadvantages (either low power density for DCM or low efficiency due to increased switching losses for BCM). To overcome the above, a hybrid DBCM operation is proposed hereafter, taking into consideration that a smooth transition between the two operating modes needs to be achieved in order to have good output power quality. The mathematical analysis for the hybrid operating mode is presented and validated through simulation and experimental results.

	ANN-Based Extraction Approach of PV Cell Equivalent Circuit Parameters By Adel GASTLI	[View] [Download]
Abstract: In most practical cases, a PV array is constructed from a combination of standard PV units (solar cells or panels) connected in series and/or in parallel to obtain the desired power, voltage and current ratings. However, the non-linear behavior of solar cells or panels makes accurate determination of the model parameters a difficult task. A precise determination of the internal physical parameters of cells and panels is not always possible because of the non-uniqueness of the solution. As a result, some parameters of the PV panel model are estimated with non-negligible errors. In this paper, an advanced ANN-based determination approach of PV array parameters from individual cell/panel characteristics is developed for single-diode model. A proper selection of the training points for the ANN is also introduced to improve the estimation of the model. Simulation results obtained for simple case studies using Matlab/Simulink software are presented and discussed. The proposed ANN-based technique made possible more accurate determination of the parameters of the single-diode model with mean errors below 1\% for all parameters except for the diode saturation and diffusion current which reached 11\%.

	Applying Fault Ride Through Capability to Single Phase Grid Connected PV Systems By IOANNIS PERPINIAS	[View] [Download]
Abstract: The grid-tied low voltage photovoltaics are expanded day by day. Aiming for a high penetration level, the Fault Ride Through Capability (FRTC) standard should be extended to these units as well. In this paper, the behavior of Single Phase Grid Connected PV Systems under faulty conditions is investigated. For this purpose, a SPWM controlled full bridge voltage source inverter is used. The proposed control concept emerges from the conventional synchronous generator behavior during faults. In this way, the low voltage distributed PV Systems can contribute during faults with currents quite higher than their nominal ones, serving the FRTC demands by injecting reactive power amounts. However, in case of excessive inverter faulty currents, current limiters are enabled. The introduced control is validated by simulation results, emphasizing at the transient interval between the fault occurrence and the steady-state faulty situation. Furthermore, the impact of the inverter's equivalent impedance is investigated, regarding the inverter's current and the resulting active and reactive power injection.

	Cascaded H-bridge control for PV application By JAYANTI GANESH	[View] [Download]
Abstract: In this paper, application of a cascaded H-bridge (CHB) converter to connect strings of solar panels to a single-phase medium voltage AC grid is discussed. With solar insolation levels differing from one string to another, it is challenging to control a CHB converter in order to minimize the variations in the dc link voltages of each of the converter modules and hence the device voltage stress levels. To minimize the device voltage stresses, in this paper, a new Maximum Power Point Tracking (MPPT) method is proposed. The proposed method equalizes the power drawn from each of the solar strings connected to the CHB across a large geographical area (e.g. along a railway line) and avoids excess device stresses. The proposed MPPT method is verified using simulation results.

	Comparison of continuous and transition mode in a PV-booster with GaN-transistors and switching frequencies up to 250 kHz By David DERIX	[View] [Download]
Abstract: A 1.8 kW boost converter for a PV-inverter with a switching frequency up to 250 kHz is analyzed.The boost converter consists of two parallel legs and the hardware is built so that chokes andsemiconductors can be exchanged easily. Two different operating modes, the Continuous InductionCurrent Mode (CICM) with a fixed switching frequency of fS = 250 kHz and the Transition Mode(TM) with a variable switching frequency are compared. The basic operation principles are explainedand efficiency measurements on real hardware under different conditions (output power,semiconductors (GaN/Si)) are shown. An improved version of the Transition Mode is developedwhich leads to higher efficiencies. Exceptional efficiencies of _max,CICM = 98.2 \% in CICM atfS = 250 kHz and _max,eTM = 98.7 \% in enhanced TM are obtained.

	Fault Ride Through Control by using New Real Time Symmetrical Coordinate Transformation By Xiaoxiao YU	[View] [Download]
Abstract: This paper proposes a real time symmetrical coordinate transformation applied for detection of imbalanced fault in utility power system. The power conditioner of the photovoltaic system in Japan is required to remain connected when the utility power system fault occurs under certain condition. The most popular fault is 1 line-to-ground fault. The next is 2 line-short fault. Both cause the imbalance voltages and currents in 3-phase power system. To optimize the output from the power conditioner of the photovoltaic system, the detection of the imbalanced condition is important factor. In this paper, new development of the signal processing method by using the complex number algebra in real time system is shown. The fast detection of the imbalanced condition is verified by the computer simulations.

	Input-Voltage Sliding Mode Control for Improving Energy Harvesting of Grid-Connected PV Inverters By SHUO YAN	[View] [Download]
Abstract: In this paper, we propose the use of sliding mode (SM) control to improve the maximum power point tracking (MPPT) performance of a two-stage single-phase inverter (comprising a first-stage DC/DC boost converter and a second-stage full-bridge inverter) in photovoltaic (PV) systems. To underscore the benefits of SM control, the MPPT performance of the PV system under the SM control is compared to that of an optimally-tuned proportional-integral (PI) control under the same PV system setup. To ease the comparison, a methodology of quantifying the measurements, which provides a clear graphical indication of the quality of the tracking, is proposed as a general platform to examine the performance. Experimental results show that the SM control can guarantee a better tracking accuracy over a larger operating range than the PI control when the weather conditions are changed dynamically throughout the course of a day. Additional comparisons based on the proposed methodology further supports that the SM control can improve the MPPT accuracy of the PV system, thus increasing the overall amount of energy harvested.

	Low Power Interleaved DC-DC Converter with High Voltage Gain for Photovoltaic Applications By António MARTINS	[View] [Download]
Abstract: Before being injected into the electric grid, the energy provided by a photovoltaic panel must be conditioned in several stages. In the micro-inverter concept, the low voltage at the output of a panel is elevated using a DC-DC converter, being the power controlled by a maximum power point tracking algorithm in such a way that the panel always works around its maximum power point. The paper presents the design and implementation of a DC-DC converter based on the three-state switching cell and voltage multipliers. The converter can be easily integrated in low-power photovoltaic applications due to its high voltage conversion ratio, high efficiency and power density. The main design parameters are discussed and a precise converter model is presented. Simulation and experimental results for an extended input voltage range show the validity of the design approach and the suitability of the converter for micro-inverterapplications.

	Phase Shifted Maximum Power Point Tracking in a Cascaded H-Bridge Photovoltaic System By Nathan MARKS	[View] [Download]
Abstract: Multilevel Cascaded H-Bridge (CHB) converters have attractive features for the implementation of largescale photovoltaic systems. They can be directly connected to high voltages and the multilevel voltagesynthesis reduces the harmonic distortion introduced. In addition, they have individual DC links ideal forconnecting photovoltaic arrays. Existing high performance voltage balancing techniques can also be adaptedto integrate Maximum Power Point Tracking (MPPT). This paper considers the impact of Perturb and Ob-serve Maximum Power Point Tracking on the performance of a 19 level three phase CHB converter andproposes the new method of Phase Shifted Perturb and Observe Maximum Power Point Tracking.

	PWM Converter Integrating Switched Capacitor Voltage Equalizer for Photovoltaic Modules under Partial Shading By Masatoshi UNO	[View] [Download]
Abstract: Various kinds of voltage equalizers have been proposed in order to preclude negative impacts of partial shading issues in photovoltaic (PV) systems. However, in addition to a converter to control a PV string, a voltage equalizer needs to be installed in a PV system, increasing the system complexity and cost. In this paper, a PWM converter integrating a switched capacitor (SC) voltage equalizer for PV modules under partial shading is proposed. A PWM converter and SC voltage equalizer can be integrated into a single unit without increasing the component count, achieving the system- and circuit-level simplification. The proposed integrated converter is compared with a conventional system using a converter and equalizer separately, from various aspects, such as voltage step-down ratio, total device power rating (TDPR) and converter size metrics. Furthermore, a dc equivalent circuit of the integrated converter, which can dramatically reduce simulation burden and time, is derived. Experimental tests using a 100-W prototype were performed for three modules connected in series under an emulated shading condition. The extractable maximum power from the string was dramatically increased by preventing the partial shading issues while the generated power from the string was transferred to the load, demonstrating the efficacy of the proposed integrated converter.

	Quantified Evaluation and Criteria Analysis for Distributed MPPT PV System By Feng WANG	[View] [Download]
Abstract: Distributed Maximum Power Point Tracking (DMPPT) concept provides effective anti-mismatchfeature, however, it fails in extreme mismatch situation. To get full profit from PV system,quantitatively static analyzes of major DMPPT structures are presented. The existence criteria andquantitative evaluation method for optimal power region of different DMPPT structures are firstproposed. Simulation and experimental case study are provided to prove the effectiveness of theproposal.

	Repetitive Control of Flyback Inverter for PV Power Applications By Sungho LEE	[View] [Download]
Abstract: In this paper, a repetitive controller (RC) is proposed for flyback inverter operating in continuous conduction mode, which has simple structure, low cost, and high efficiency. Conventional controller results in poor control performance due to the effect of the right-half-plane zero in CCM operation. To achieve the fast dynamical response, the repetitive controller is developed and applied to flyback inverter in CCM operation. In RC scheme, a low-pass filter is adopted in the repetitive control scheme to enhance the robustness of repetitive controller. The stability of closed-loop system is derived and the zero tracking error is achieved. Numerical simulations and experiments are performed to validate the proposed control approach.

	SysML Methodology for HiL Implementation of PV Models By Harold CHAMORRO	[View] [Download]
Abstract: This paper describes a methodology for implementing in FPGA models of photovoltaic panels for Hardware in-the-Loop (HIL) and real-time simulations. The proposed methodology integrates numerical solutions, SysML diagrams and Petri nets for structural design and formal validation. In this study, photovoltaic cells have been modeled using the single diode circuit. The photovoltaic panel model is solved by the Newton-Raphson method, and the Lagrange remainder is employed to limit the iteration number. Results show suitable accuracy and performance of the proposed methodology.