EPE Association: EPE 2016 - DS3f: Solar Energy Systems

EPE 2016 - DS3f: Solar Energy Systems
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2016 ECCE Europe - Conference > EPE 2016 - Topic 05: Renewable Energy Power Systems > EPE 2016 - DS3f: Solar Energy Systems

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   A Copper-loss Based Design Method and Verification for a Zero-ripple Interface for PV / Battery-to-Grid Applications
By Suvankar BISWAS [View]
[Download]

Abstract: A systematic design of a zero-ripple Cuk converter for PV/Battery-to-grid dc-dc conversion is presented. This paper derives the copper loss geometrical constant (Kg) for this kind of integrated magnetic core using a simplified yet intuitive flux-reluctance model. Unlike earlier designs, the design procedure is completely analytical and valid for a range of duty-ratio operation. Verification is done by finite element methods and circuit simulations.

   An Improved Simulated Annealing Maximum Power Point Tracking Technique for PV Array under Partial Shading Conditions
By Yusen FAN [View]
[Download]

Abstract: This paper presents an improved Simulated Annealing (SA) based Maximum Power Point Tracking (MPPT) technique designed for photovoltaic (PV) systems under partial shading conditions (PSC). Compared with existing SA MPPT algorithms, the proposed method performs faster convergence speed, higher tracking accuracy and continuously tracking of the global Maximum Power Point (GMPP) under climate changes. The new SA MPPT principle is fully explained, discussed and verified by simulation.

   Assessment and monitoring of grid-tied PV inverter performance using a 'golden inverter' model
By Kasper PAASCH [View]
[Download]

Abstract: A method to define a best case behavioural or 'golden inverter' software model has been developed, derived from either internal inverter readings (internal), high precision site based measurements or laboratory characterization and well defined conditions. The paper describes the method of the model development as well as the performance of the model for a selected use case.

   Dynamic Modeling of DC Nanogrid Local Branch using Enhanced PV and Third Order Battery Models
By Maged BAUOMY [View]
[Download]

Abstract: Distributed generation via residential branches connected to DC buses are going increased considered an open energy system. These residential branches DC buses have a lot of different shapes forming several types. One of these types is using photovoltaic PV and battery storage system (BSS) connected to main DC bus or multi-terminal DC (MTDC) buses. Recently, this is named DC nanogrid interconnected together forming DC microgrid. In this regard, this paper presents a type of these nanogrid local branch systems (NG-LBS) for residential PV and BSS in detailed modeling and implementing a new assemblage by using enhanced photovoltaic diode model (EPVDM) array, coupled to DC-DC boost converter and maximum power point tracking (MPPT). A novel technique for MPPT is polynomial computational method (PCM) has been used. The BSS has been presented in detailed dynamic model through lead acid battery type by applying third order thevenin equivalent circuit connected in parallel with the single terminal DC (STDC) home load bus. The dynamic behavior for NG-LBS has been shown via dynamic PV with boost converter and PCM MPPT and integrated with the dynamical third order lead acid BSS for charging, discharging and constant charge cases at different radiations and loads.

   Effective Method for Filter Design and Semiconductor and Inductors Loss Calculation
By Stefan HOFFMANN [View]
[Download]

Abstract: Predicting semiconductor and inductor losses together with designing the EMC filter for grid feeding inverters requires great effort, when high and variable pulse frequencies and triangular current mode are applied. In this paper an effective method is proposed to quickly evaluate the effect of circuit and control strategy on losses and inverter size. With this approach the system is modeled using only a few representative operation points, which leads to a significant effort reduction. The approach is validated on a 2 kW one phase DC-AC converter according to the requirements of 'The Google/IEEE PELS Little Box Challenge'.

   Evaluation of three-phase solar inverters using SiC devices
By Simon WALL [View]
[Download]

Abstract: An evaluation is performed for three-phase solar Photo-Voltaic (PV) inverters using either Silicon (Si) or Silicon Carbide (SiC) power devices. Standard and emerging topologies for high-efficiency (=98\%) PV inverters are identified and optimized for the capital cost of power filter components and power devices. Analytical formulae are developed for minimum filter inductance considering both current ripple and core-loss constraints. For string-type PV inverters, SiC power devices are shown to be cost competitive compared with Si power devices. Three example PV inverter designs are presented to showcase the use of SiC power devices. Experimental results demonstrate efficiency in excess of 98\%.

   Fast Maximum Power Point Tracking for PV Arrays under Partial shaded Conditions
By Ghasemi MOHAMMAD AMIN [View]
[Download]

Abstract: P-V characteristic of photovoltaic (PV) arrays under partially shaded conditions (PSC) has multiple peaks, and conventional maximum power point tracking (MPPT) algorithms may fail to track the global maximum power point (GMPP) because of their insufficient intelligence in discriminating the local and global peaks. This paper proposes a novel fast MPPT method to achieve GMPP of PV array under all PSCs. The proposed method reduces the number of required samples and increases the speed of GMPP tracking based on comprehensive study of I-V and P-V characteristics of PV array. Performance of the proposed method has been evaluated in simulations of different PSCs. Also, its performance has been compared with two selected methods in the literature through simulations. Comparisons highlight the superiority of the proposed method.

   High Gain Inverter based on the 3S Inverter with Model Predictive Control for PV Applications
By Omar ABDELRAHIM [View]
[Download]

Abstract: this paper presents two-stage power conditioning system for grid integrated Photovoltaic (PV) applications. The proposed system has distinct feature such as: high voltage gain, high efficiency, low voltage stress and galvanic isolation. The system is controlled via Model Predictive Control (MPC) to do the following functions: extract maximum power from the PV generator, and inject a sinusoidal current into the utility with unity power factor.

   Loss Distribution Analysis of a Three-Port Converter for Low-Power Stand-Alone Light-to-Light Systems
By MARIA DEL CARMEN MIRA ALBERT [View]
[Download]

Abstract: In locations far from the equator achieving high conversion efficiency in low-power solar systems ischallenging due to low solar irradiance levels. This paper presents a high efficiency three-port converter(TPC) for light-to-light (LtL) applications where no direct solar conversion is required. The separationof the power flows allows to replace the conventional solution of two cascaded converters into a singlestructure with shared components. A loss distribution analysis of the proposed structure is performed,which shows very good match with the experimental results. A prototype of the TPC demonstrates highefficiency in both power flow paths. At low irradiation level, the photovoltaic to battery stage shows apeak efficiency of 99.1 \% at at 1.5 W output power and the LED driver stage presents a peak efficiencyof 97.3 \% at 3 W output power.

   New Configuration for High-efficient Operation of Partially Shaded PV System using an Electromagnetic Relay
By Ikuo NANNO [View]
[Download]

Abstract: The output power of the partially shaded photovoltaic (PV) array is greatly reduced due to the blocking of the direct sunlight, and the current difference between the shaded and illuminated PV modules. For increasing the efficiency of the partially shaded PV array, a new configuration using an electromagnetic relay is proposed. This configuration is mainly used for collecting all currents of the shaded modules using the contacts of the electromagnetic relay. Therefore, the shaded modules in the new configuration delivered more output power with creating only one peak on the PV array characteristic for proper and simple functioning of the maximum power tracker. The simulation and experimental data validate the effectiveness of the new configuration for the power recovery of the partially shaded PV array using only an electromagnetic relay.

   New Dual-Mode Variable Step-Size Control Strategy For Quadratic Boost Converter Used in Solar Energy System
By Ahmad GHAMRAWI [View]
[Download]

Abstract: This paper presents a new control strategy based on Lyapunov theory used to control a quadratic boost converter used in solar energy system. The proposed controller assures the stability of the system. To provide a maximum power extraction, a maximum power point tracking (MPPT) is included in the controller. First a simple MPPT algorithm based on the fact that the derivative of the power with respect to the voltage at the output of the solar panel is null when the operating point is the same as the maximum power point (MPP) is integrated in the controller, then we will propose a modified version of the algorithm operating in dual-mode with a variable step-size. The proposed controller is tested by simulations using Matlab/SimulinkTM with both MPPT algorithms. The proposed dual-mode variable step-size algorithm has proved its advantage compared to the simple one. It gives a smoother output, therefore decreases power losses. The proposed controller is compared also to a conventional perturb and observe (P&O) controller. The comparison has proved that the proposed controller has a smaller response time, a lower steady-state error and a more stable operating point.

   Optimum Design of a Flyback PV Microinverter under Hybrid DCM/BCM Operation
By Georgios CHRISTIDIS [View]
[Download]

Abstract: The Current-Source Flyback microinverter is widely used in ac-PV module applications, either in Discontinuous Conduction Mode (DCM), Continuous Conduction Mode (CCM) or Boundary Conduction Mode (BCM). The recently proposed hybrid DCM/BCM operation inherits the merits of both discrete conduction modes and improves the converter performance. In this work a power loss analysis of the hybrid operation is conducted for each converter component and a design optimization algorithm is applied, focusing on the appropriate selection of each converter component and parameter, in order to achieve maximum weighted efficiency. The mathematical analysis is validated using a laboratory experimental prototype.

   State-Vector Feedback Gain Analysis for Deadbeat Control of Grid-Integrated Inverter with LCL filter
By Tarek AHMED [View]
[Download]

Abstract: This paper presents the control method of an LCL filter implemented for a three-phase, voltage-source, grid-connected inverter for not only offering better attenuation of switching harmonics but also for highly damping the resonance. A discrete-time deadbeat current controller with tuned state-feedback gains is proposed to realize the time optimum responses with high control accuracy. In addition, the influences of different grid inductances and switching frequencies of the three-level T-type inverter on the controller gains are discussed. The analytical design of the three dimensional deadbeat controller dealing with the instantaneous space vectors is examined under varying grid inductance. The effectiveness of the optimum feedback gains on the control performance is validated experimentally. The deadbeat controller can provide the fastest response and damp the resonance of the LCL filter at relatively low switching frequency in comparison with the filter size.

   Sub-module Differential Power Processing Photovoltaic Optimizer Using Self-adjusted Time-sharing Maximum Power Point Tracking Control Strategy
By Tianhua ZHU [View]
[Download]

Abstract: Differential power processing (DPP) has demonstrated its significant advantage of high systemefficiency for photovoltaic (PV) applications especially in mismatch conditions. In this paper, a submoduleDPP based PV optimizer using a self-adjusted time-sharing maximum power point tracking(MPPT) control strategy is proposed, which can achieve fast and accurate tracking of all sub-modules'maximum power points (MPPs) with only one MPPT controller, facilitating system integration andlargely reducing system cost and conversion loss. The effectiveness of the proposed solution is verifiedby both simulation and experiments.

EPE 2016 - DS3f: Solar Energy Systems
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2016 ECCE Europe - Conference > EPE 2016 - Topic 05: Renewable Energy Power Systems > EPE 2016 - DS3f: Solar Energy Systems
	[return to parent folder]

	A Copper-loss Based Design Method and Verification for a Zero-ripple Interface for PV / Battery-to-Grid Applications By Suvankar BISWAS	[View] [Download]
Abstract: A systematic design of a zero-ripple Cuk converter for PV/Battery-to-grid dc-dc conversion is presented. This paper derives the copper loss geometrical constant (Kg) for this kind of integrated magnetic core using a simplified yet intuitive flux-reluctance model. Unlike earlier designs, the design procedure is completely analytical and valid for a range of duty-ratio operation. Verification is done by finite element methods and circuit simulations.

	An Improved Simulated Annealing Maximum Power Point Tracking Technique for PV Array under Partial Shading Conditions By Yusen FAN	[View] [Download]
Abstract: This paper presents an improved Simulated Annealing (SA) based Maximum Power Point Tracking (MPPT) technique designed for photovoltaic (PV) systems under partial shading conditions (PSC). Compared with existing SA MPPT algorithms, the proposed method performs faster convergence speed, higher tracking accuracy and continuously tracking of the global Maximum Power Point (GMPP) under climate changes. The new SA MPPT principle is fully explained, discussed and verified by simulation.

	Assessment and monitoring of grid-tied PV inverter performance using a 'golden inverter' model By Kasper PAASCH	[View] [Download]
Abstract: A method to define a best case behavioural or 'golden inverter' software model has been developed, derived from either internal inverter readings (internal), high precision site based measurements or laboratory characterization and well defined conditions. The paper describes the method of the model development as well as the performance of the model for a selected use case.

	Dynamic Modeling of DC Nanogrid Local Branch using Enhanced PV and Third Order Battery Models By Maged BAUOMY	[View] [Download]
Abstract: Distributed generation via residential branches connected to DC buses are going increased considered an open energy system. These residential branches DC buses have a lot of different shapes forming several types. One of these types is using photovoltaic PV and battery storage system (BSS) connected to main DC bus or multi-terminal DC (MTDC) buses. Recently, this is named DC nanogrid interconnected together forming DC microgrid. In this regard, this paper presents a type of these nanogrid local branch systems (NG-LBS) for residential PV and BSS in detailed modeling and implementing a new assemblage by using enhanced photovoltaic diode model (EPVDM) array, coupled to DC-DC boost converter and maximum power point tracking (MPPT). A novel technique for MPPT is polynomial computational method (PCM) has been used. The BSS has been presented in detailed dynamic model through lead acid battery type by applying third order thevenin equivalent circuit connected in parallel with the single terminal DC (STDC) home load bus. The dynamic behavior for NG-LBS has been shown via dynamic PV with boost converter and PCM MPPT and integrated with the dynamical third order lead acid BSS for charging, discharging and constant charge cases at different radiations and loads.

	Effective Method for Filter Design and Semiconductor and Inductors Loss Calculation By Stefan HOFFMANN	[View] [Download]
Abstract: Predicting semiconductor and inductor losses together with designing the EMC filter for grid feeding inverters requires great effort, when high and variable pulse frequencies and triangular current mode are applied. In this paper an effective method is proposed to quickly evaluate the effect of circuit and control strategy on losses and inverter size. With this approach the system is modeled using only a few representative operation points, which leads to a significant effort reduction. The approach is validated on a 2 kW one phase DC-AC converter according to the requirements of 'The Google/IEEE PELS Little Box Challenge'.

	Evaluation of three-phase solar inverters using SiC devices By Simon WALL	[View] [Download]
Abstract: An evaluation is performed for three-phase solar Photo-Voltaic (PV) inverters using either Silicon (Si) or Silicon Carbide (SiC) power devices. Standard and emerging topologies for high-efficiency (=98\%) PV inverters are identified and optimized for the capital cost of power filter components and power devices. Analytical formulae are developed for minimum filter inductance considering both current ripple and core-loss constraints. For string-type PV inverters, SiC power devices are shown to be cost competitive compared with Si power devices. Three example PV inverter designs are presented to showcase the use of SiC power devices. Experimental results demonstrate efficiency in excess of 98\%.

	Fast Maximum Power Point Tracking for PV Arrays under Partial shaded Conditions By Ghasemi MOHAMMAD AMIN	[View] [Download]
Abstract: P-V characteristic of photovoltaic (PV) arrays under partially shaded conditions (PSC) has multiple peaks, and conventional maximum power point tracking (MPPT) algorithms may fail to track the global maximum power point (GMPP) because of their insufficient intelligence in discriminating the local and global peaks. This paper proposes a novel fast MPPT method to achieve GMPP of PV array under all PSCs. The proposed method reduces the number of required samples and increases the speed of GMPP tracking based on comprehensive study of I-V and P-V characteristics of PV array. Performance of the proposed method has been evaluated in simulations of different PSCs. Also, its performance has been compared with two selected methods in the literature through simulations. Comparisons highlight the superiority of the proposed method.

	High Gain Inverter based on the 3S Inverter with Model Predictive Control for PV Applications By Omar ABDELRAHIM	[View] [Download]
Abstract: this paper presents two-stage power conditioning system for grid integrated Photovoltaic (PV) applications. The proposed system has distinct feature such as: high voltage gain, high efficiency, low voltage stress and galvanic isolation. The system is controlled via Model Predictive Control (MPC) to do the following functions: extract maximum power from the PV generator, and inject a sinusoidal current into the utility with unity power factor.

	Loss Distribution Analysis of a Three-Port Converter for Low-Power Stand-Alone Light-to-Light Systems By MARIA DEL CARMEN MIRA ALBERT	[View] [Download]
Abstract: In locations far from the equator achieving high conversion efficiency in low-power solar systems ischallenging due to low solar irradiance levels. This paper presents a high efficiency three-port converter(TPC) for light-to-light (LtL) applications where no direct solar conversion is required. The separationof the power flows allows to replace the conventional solution of two cascaded converters into a singlestructure with shared components. A loss distribution analysis of the proposed structure is performed,which shows very good match with the experimental results. A prototype of the TPC demonstrates highefficiency in both power flow paths. At low irradiation level, the photovoltaic to battery stage shows apeak efficiency of 99.1 \% at at 1.5 W output power and the LED driver stage presents a peak efficiencyof 97.3 \% at 3 W output power.

	New Configuration for High-efficient Operation of Partially Shaded PV System using an Electromagnetic Relay By Ikuo NANNO	[View] [Download]
Abstract: The output power of the partially shaded photovoltaic (PV) array is greatly reduced due to the blocking of the direct sunlight, and the current difference between the shaded and illuminated PV modules. For increasing the efficiency of the partially shaded PV array, a new configuration using an electromagnetic relay is proposed. This configuration is mainly used for collecting all currents of the shaded modules using the contacts of the electromagnetic relay. Therefore, the shaded modules in the new configuration delivered more output power with creating only one peak on the PV array characteristic for proper and simple functioning of the maximum power tracker. The simulation and experimental data validate the effectiveness of the new configuration for the power recovery of the partially shaded PV array using only an electromagnetic relay.

	New Dual-Mode Variable Step-Size Control Strategy For Quadratic Boost Converter Used in Solar Energy System By Ahmad GHAMRAWI	[View] [Download]
Abstract: This paper presents a new control strategy based on Lyapunov theory used to control a quadratic boost converter used in solar energy system. The proposed controller assures the stability of the system. To provide a maximum power extraction, a maximum power point tracking (MPPT) is included in the controller. First a simple MPPT algorithm based on the fact that the derivative of the power with respect to the voltage at the output of the solar panel is null when the operating point is the same as the maximum power point (MPP) is integrated in the controller, then we will propose a modified version of the algorithm operating in dual-mode with a variable step-size. The proposed controller is tested by simulations using Matlab/SimulinkTM with both MPPT algorithms. The proposed dual-mode variable step-size algorithm has proved its advantage compared to the simple one. It gives a smoother output, therefore decreases power losses. The proposed controller is compared also to a conventional perturb and observe (P&O) controller. The comparison has proved that the proposed controller has a smaller response time, a lower steady-state error and a more stable operating point.

	Optimum Design of a Flyback PV Microinverter under Hybrid DCM/BCM Operation By Georgios CHRISTIDIS	[View] [Download]
Abstract: The Current-Source Flyback microinverter is widely used in ac-PV module applications, either in Discontinuous Conduction Mode (DCM), Continuous Conduction Mode (CCM) or Boundary Conduction Mode (BCM). The recently proposed hybrid DCM/BCM operation inherits the merits of both discrete conduction modes and improves the converter performance. In this work a power loss analysis of the hybrid operation is conducted for each converter component and a design optimization algorithm is applied, focusing on the appropriate selection of each converter component and parameter, in order to achieve maximum weighted efficiency. The mathematical analysis is validated using a laboratory experimental prototype.

	State-Vector Feedback Gain Analysis for Deadbeat Control of Grid-Integrated Inverter with LCL filter By Tarek AHMED	[View] [Download]
Abstract: This paper presents the control method of an LCL filter implemented for a three-phase, voltage-source, grid-connected inverter for not only offering better attenuation of switching harmonics but also for highly damping the resonance. A discrete-time deadbeat current controller with tuned state-feedback gains is proposed to realize the time optimum responses with high control accuracy. In addition, the influences of different grid inductances and switching frequencies of the three-level T-type inverter on the controller gains are discussed. The analytical design of the three dimensional deadbeat controller dealing with the instantaneous space vectors is examined under varying grid inductance. The effectiveness of the optimum feedback gains on the control performance is validated experimentally. The deadbeat controller can provide the fastest response and damp the resonance of the LCL filter at relatively low switching frequency in comparison with the filter size.

	Sub-module Differential Power Processing Photovoltaic Optimizer Using Self-adjusted Time-sharing Maximum Power Point Tracking Control Strategy By Tianhua ZHU	[View] [Download]
Abstract: Differential power processing (DPP) has demonstrated its significant advantage of high systemefficiency for photovoltaic (PV) applications especially in mismatch conditions. In this paper, a submoduleDPP based PV optimizer using a self-adjusted time-sharing maximum power point tracking(MPPT) control strategy is proposed, which can achieve fast and accurate tracking of all sub-modules'maximum power points (MPPs) with only one MPPT controller, facilitating system integration andlargely reducing system cost and conversion loss. The effectiveness of the proposed solution is verifiedby both simulation and experiments.