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EPE 2013 - DS3h: Non-Rotating Power Generation and Storage Systems
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2013 ECCE Europe - Conference > EPE 2013 - Topic 15: Non-rotating power generation and storage systems > EPE 2013 - DS3h: Non-Rotating Power Generation and Storage Systems
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	A Hybrid Cascaded Multi-level Converter for Power Storage System   By Zedong ZHENG, Ling PENG, Kui WANG, Lie XU, Yongdong LI	[View]   [Download]
Abstract: Power storage system using battery and super-capacitor are more and more popular in renewable energy, smart grid and electrical vehicles. But the voltage and current of the basic battery cells and super-capacitor are limited. So in practical applications, a large number of cells are connected in seriously or parallel to improve the output voltage and current ability. Due to the differences between the cells, voltage and current equalizations are necessary to prevent overcharge or over-discharge on some cells. In this paper, a novel hybrid cascaded multi-level converter is proposed to solve the voltage equalization problems. The battery cells are connected by the cascaded half-bridges instead of being connected directly. The charge and discharge of the battery cells can be controlled separately and then the voltage equalization can be realized. Some experimental results will be given to verify the effects of the proposed converter.
	A Novel Grid Impedance Estimation Technique based on Adaptive Virtual Resistance Control Loop Applied to Distributed Generation Inverters   By Walid GHZAIEL, Manel JEBALI-BEN GHORBAL, Ilhem SLAMA-BELKHODJA, Josep GUERRERO	[View]   [Download]
Abstract: The penetration of the distributed power generation systems (DPGSs) based on renewable sources (PV, WT) is strongly dependent on the quality of the power injected to the utility grid. However, the grid impedance variation, mainly caused by grid faults somewhere in the electric network, can degrade the power quality and even damage some sensitive loads connected at the point of the common coupling (PCC). This paper presents detection-estimation method of the grid impedance variation. This estimation technique aims to improve the dynamic of the distributed generation (DG) interfacing inverter control and to take the decision of either keep the DG connected, or disconnect it from the utility grid. The proposed method is based on a fast and easy grid fault detection method. A virtual damping resistance is used to drive the system to the resonance in order to extract the grid impedance parameters, both resistive and inductive parts, using resonant filter frequency determination. Theoretical analysis and simulation results are presented to validate the proposed method.
	Adaptive Droop for Primary Control in MTDC Networks with Energy Storage   By Catalin GAVRILUTA, Ignacio CANDELA, Alvaro LUNA, Joan ROCABERT, Pedro RODRIGUEZ	[View]   [Download]
Abstract: This paper proposes a passive filter design method and validation analysis based on a Trap-LCL filter topology for implementation in grid connected two-level converters for high power applications. The proposed topology appears as an alternative to the conventional LCL filter, since reduced filter parameters can be obtained while still ensuring high filtering capability for switching frequency harmonics. Furthermore, a step-by-step filter design method will be introduced in order to provide a clear scope on the tuning procedure, as well as on the main requirements that the filter should satisfy. Finally, a comparative study between a conventional LCL and a LCL-Trap filter will be performed in simulation with the goal of finding a meaningful evaluation of the advantages and disadvantages provided from the LCL-Trap configuration.
	An Electromechanical Model for a Dielectric ElectroActive Polymer Generator   By Emmanouil DIMOPOULOS, Bjorn RECHENBACH, Ionut TRINTIS, Stig MUNK-NIELSEN, Morten WILLATZEN, Benny LASSEN	[View]   [Download]
Abstract: Smart electroactive materials have attracted much of the scientific interest over the past few years, asthey reflect a quite promising alternative to conservative approaches used nowadays in various transducer applications. Especially Dielectric ElectroActive Polymers (DEAPs), which are constantly gaining momentum due to their superior low-speed performance, light-weighted nature and higher energy density when compared with competing technologies. In this paper an electromechanical model for a DEAP generator is presented, accounting for both the visco-hyperelastic characteristics of the polymer material, as well as the later one’s experimentally determined stretch-capacitance dependence. Apart from the visco-hyperelastic model validation via purely mechanical experiments, the model’s electromechanical coupling is verified as well, via experiments conducted under all three distinct energy harvesting cycles; namely the Constant Charge (CC), Constant Voltage (CV) and Constant E-field (CE) cycles.
	An Interleaved Flyback Inverter for Residential Photovoltaic Applications   By Bunyamin TAMYUREK, Bilgehan KIRIMER	[View]   [Download]
Abstract: This study presents the analysis, design, and implementation of a photovoltaic (PV) inverter for residential applications based on interleaved flyback topology operated in discontinuous current mode (DCM). It is expected that the use of solar energy in small electric power system applications will increase largely when the cost of the PV panels and the energy conversion equipment becomes economical for every user. Therefore, the objective of this study is to develop a low-cost inverter system. The cost reduction is achieved by selecting the lowest cost converter topology, simplifying the control system, and making a compact and small size converter. The selected topology and the operating mode are known to yield the lowest component count and so the lowest cost. The paper first performs analysis and design on a 1 kW system then obtains the PLECS and the Simulink models for simulation. Later, using the simulation results, the inverter design and the controller performances are verified and optimized for the given specifications. Lastly, a full-scale prototype is built and evaluated under realistic conditions. Based on the experimental results, the implemented design and the controller can extract the energy from the solar panels with 97\% efficiency and transfer it to the grid with high power quality and with 86.14\% static efficiency at full load. The total harmonic distortion (THD) of the grid current is measured as 3.68\% and the power factor is very close to unity. Consequently, the experimental results demonstrate that the proposed inverter system and its design perform successfully and comply with the existing PV inverter specifications.
	Analysis of Power Loss of a Grid Connected PV-Inverter with Si- and SiC-Transistors for Generation of Reactive Power   By Christian WILHELM, Juergen THOMA, David DERIX	[View]   [Download]
Abstract: Due to new grid codes for grid connected photovoltaic power generation, since 2012 PV inverters have to be able to feed in reactive power down to a power factor of cos(φ)=0.9 besides their normal operation with pure active power [1]. In this paper the influence of different semiconductors on the power losses as function of the power factor will be studied on the base of a three-level MNPC topology. In the first step an analytical method will be found to determine the losses, based on the methods shown in [2], [3] and [4] for full-bridge and NPC topology. Then in the second step the theoretical results will be refined by using a simulation software for power electronics. Finally the power losses from both theoretical methods will be compared to those of a real measurement setup to verify the correctness of these results. Different types of Si-IGBTs and SiC-JFETs are used. Depending on the selected transistors, the power losses increase or decrease with the power factor cos(φ).
	Comparison of RB-IGBT and Normal IGBT in T-type Three-level Inverter   By Kai SUN, Lipei HUANG, Seiki IGARASHI, Li ZHANG	[View]   [Download]
Abstract: A T-type three-level inverter topology with RB-IGBT is researched. The operation modes andmodulation strategy is analyzed. The power loss of T-type inverter with RB-IGBT and normal IGBT iscalculated and compared. Experimental results show that T-type inverter with RB-IGBT has betterefficiency than that of normal IGBT.
	Emulation of Photovoltaic Arrays with Shading Effect for Testing of Grid-Connected Inverters   By Thomas GEURY, Johan GYSELINCK	[View]   [Download]
Abstract: This paper deals with the development of a Photovoltaics (PV) emulator for testing grid-connected inverters, taking the shading effect on the panels into account. The Single Exponential Model (SEM) of a PV array is used with appropriate approximations. The shading effect is modeled for a configuration of series connected panels, with bypass diodes, and two irradiance levels. This PV modeling is used in a retroactive loop in order to output a voltage reference corresponding to the current measured at the output of the emulator. After being regulated by a Proportional-Integral (PI) controller, this reference produces the duty cycle for the Pulse Width Modulation (PWM) of the DC/DC converter, whose objective is to reproduce this voltage. The emulation is tested first with a resistive load, where it is observed that the characteristic curves of the panels are accurately reproduced, and then on a commercial grid-connected inverter. A Graphical User Interface (GUI) is developed to allow modifying online the test parameters and observe the results in a convenient way so as to properly assess the response of the inverter and its Maximum Power Point Tracking (MPPT) capability. In particular, several tests validate the operation of the emulator, in a reference situation, at the start-up of the inverter and for changing atmospheric conditions.
	Energetic macroscopic representation and inversion-based control of DC microgrid   By Baochao WANG, Manuela SECHILARIU, Fabrice LOCMENT	[View]   [Download]
Abstract: This paper proposes a DC micro-grid for urban areas based on photovoltaic array and electrolyticstorage. The DC micro-grid is designed using the formalism energetic macroscopic representationfrom which a maximum control structure is defined. The control strategy is experimentally validated,and results highlight the performance of DC micro-grid.
	Filter Optimization of Si and SiC Semiconductor-based H5 and Conergy-NPC Transformerless PV Inverters    By Eftichios KOUTROULIS, Frede BLAABJERG, Stefanos SARIDAKIS	[View]   [Download]
Abstract: Single-phase transformerless Photovoltaic (PV) inverters are synthesized by combining available solutions in terms of the power section topology, power semiconductors manufacturing technology and structure of the output filter. A design method is presented in this paper for optimizing the power semiconductors type (Si- or SiC-based), switching frequency and output filter (LCL- or LLCL-type) employed in H5 and Conergy-NPC PV inverters, considering the simultaneous impact of the factors affecting the PV energy processing performance and PV inverter cost. According to the design results, the optimized SiC based PV inverters will inject more energy into the electric grid, compared to the Si based structures and enable the reduction of the output filter size, weight and cost. Employing an LLCL-type output filter and simultaneously reducing the cost of SiC power semiconductors to the level of their Si-based counterparts will enhance the economic superiority of the resulting optimized H5 and Conergy-NPC PV inverters with respect to the cost of the electricity they generate.
	High efficiency AC Photovoltaic Module: Efficiency or Reduced Number of Components_   By Luccas M. KUNZLER, Jonas R. TIBOLA, Luciano SCHUCH, Jose Renes PINHEIRO, M. L. da Silva MARTINS	[View]   [Download]
Abstract: This paper presents the analysis of two AC photovoltaic modules: i) a flyback based, and ii) a full-bridgebased. The comparative analysis takes into account the number of semiconductor components, such asswitches and diodes, and the delivered power to the grid by each topology. The full-bridge based ACmodule has one of the highest component count among all the AC modules. In spite of it, it achieveshigh efficiency and performance. On the other hand the flyback based AC module has one of the fewestcomponent count. So, the goal of the analysis carried out in this paper is to investigate whether it ispossible to deliver more power to the grid, even with a higher component count.
	High Efficiency Isolated DC/DC Converter inherently optimized for fuel cell applications   By Lars Press PETERSEN, Lasse CRONE JENSEN	[View]   [Download]
Abstract: The isolated full-bridge boost converter has been suggested as the best choice for fuel cell applications. Comparisons have been carried out in the literature using both stress factors and experimental verified designs to determine the optimal converter. Never the less, this paper suggests a different topology not previous used for fuel cell applications with some clear advantages. Taking into account the I-V characteristics of the fuel cell only emphasized the performance of the proposed converter and reveals its self as an optimal candidate for the fuel cell application.
	Isolated Full Bridge Boost DC-DC Converter Designed for Bidirectional Operation of Fuel Cells/Electrolyzer Cells in Grid-Tie Applications   By Riccardo PITTINI, Zhe ZHANG, Michael ANDERSEN	[View]   [Download]
Abstract: Energy production from renewable energy sources is continuously varying, for this reason energy storage is becoming more and more important as the percentage of green energy increases. Newly developed fuel cells can operate in reverse mode as electrolyzer cells; therefore, they are becoming an attractive technology for energy storage grid-tie applications. In this application dc-dc converter optimization is very challenging due to the large voltage range that the converter is expected to operate. Moreover, the fuel-electrolyzer cell side of the converter is characterized by low voltage and high current. Dc-dc converter efficiency plays a fundamental role in the overall system efficiency since processed energy is always flowing through the converter; for this reason, loss analysis and optimization are a key component of the converter design.The paper presents an isolated full bridge boost dc-dc converter (IFBBC) designed for this new application focusing on losses analysis. The system topology is briefly discussed and the major concerns related to the system, cells stacks and converter operating points are analyzed. The dc-dc converter losses are modeled and presented in detail; the analysis is validated on adc-dc converter prototype rated at 6 kW 30-80 V 0-80 A on the low voltage side and 700-800 V on the high voltage side (for a grid-tie application). The prototype is based on fully planar magnetic, Si MOSFETs, Si IGBTs and SiC diodes; efficiencies up to ~96.5\% and ~97.8\% were demonstrated depending on the converter operating point.
	Mission Profile based Multi-Disciplinary Analysis of Power Modules in Single-Phase Transformer-less Photovoltaic Inverters   By Yongheng YANG, Huai WANG, Frede BLAABJERG, Ke MA	[View]   [Download]
Abstract: The popularity of transformerless photovoltaic (PV) inverters in Europe proves that these topologies can achieve higher efficiency (e.g., ≥ 98\% has been reported). Along with the advanced power electronics technology and the booming development of PV power systems, a long service time (e.g. 25 years) has been set as a main target and an emerging demand from the customers, which imposes a new challenge on grid-connected transformerless inverters. In order to reduce maintenance cost, it is essential to predict the lifetime of the transformerless PV inverter and its components based on the mission profiles – solar irradiance and ambient temperature. In this paper, a mission profile based analysis approach is proposed and it is demonstrated by three main single-phase transformerless PV inverters - Full-Bridge (FB) with bipolar modulation scheme, the FB inverter with DC bypass (FB-DCBP) topology and the FB inverter with AC bypass leg (highly efficient and reliable inverter concept, HERIC inverter). Since the thermal stress is one of the most critical factors that induce failures, the junction temperatures on the power devices of the three topologies are analyzed and compared by considering the mission profiles. The lifetimes of these topologies are discussed according to the thermal performance and the power losses on the switching devices are also compared.
	Modeling and Analysis of Battery Performance for Renewable Energy Application   By Cedric CARUANA, S.M. MUYEEN, Adnan SATTAR, Ahmed AL-DURRA	[View]   [Download]
Abstract: This paper models the performance of lead acid batteries in battery energy storage systems (BESS) for renewable energy applications. The considered system consists of a permanent magnet generator based wind turbine interfaced to the grid through fully rated converters. A battery energy storage system, interfaced to the grid via STATCOM, is used for active power smoothing. A low power experimental BESS is interfaced to the system model. Two battery models, a simple- and a detailed- one, are implemented and verified against experiemntal data. A simple experiemntal test is proposed for measuring the battery internal resistance. The salient feature of this paper is the examination of the battery terminal voltage variation for the non-regular current profiles requested from the battery bank in renewable energy application.
	Modeling and Characterization of Ultra-Capacitor for Fuel Cell Vehicle Simulator   By Nabil BENYAHIA, Nacereddine BENNAMROUCHE, Toufik REKIOUA, Mustapha ZAOUIA, Denoun HAKIM, Djerdir ABDESLAM	[View]   [Download]
Abstract: The main objective of this paper is the modeling and the characterization of a hybrid power source combining ultra capacitors and proton exchange membrane fuel cell (PEMFC). The related theoretical study is validated through experimental measurements. After establishing the ultra capacitor model, a brief study of a PEMFC is presented taking into account the fuel starvation phenomenon which causes serious problems during the operating modes where the load changes rapidly, such as vehicle accelerations. To validate this study a PEMFC real time simulator has been build using dSpace device. Then, this tool has been used to demonstrate the main role of ultra capacitors in terms of preventing the starvation phenomena in FCEV
	Piezoelectric Energy Harvester With PWM Electric Interface   By Dejan VASIC, Yunxia YAO	[View]   [Download]
Abstract: In this study, an active wideband electric interface based on pulse width modulation (PWM) for piezoelectric energy harvester is investigated. The switching interfaces are used to increase the output power of energy harvesting devices for wide frequency range. The model of a piezoelectric dynamic system is built, and the active interface is developed. It is shown that the active energy harvesting technique can effectively enable harvested power to be the maximum possible value for a dynamic electromechanical system for all frequencies. The proposed wideband interface is composed of a full bridge converter with PWM modulation. The voltage is adaptive to the vibration. A theoretical analysis is proposed and an experimental result verifies our theoretical prediction. In the final experiment, the PWM interface can harvested more energy in the case of multi-frequency vibration.
	Seamless Dynamic Model for DC-DC Converters Applicable to Bi-directional Power Transfer   By Yasutaka IMAMURA, Husam A. RAMADAN, Yang SIHUN, Gamal M. DOUSOKY, Masahito SHOYAMA	[View]   [Download]
Abstract: In this paper, seamless model of bi-directional DC-DC converter which is applicable to bi-directional power transfer is proposed. Conventional modeling method of bi-directional DC-DC converter is complex, because different models are needed for different directions of power flow. On the other hand, seamless model can be applied for both directions of power flow. Seamless circuit model is expressed by voltage source and bi-polar current source, and polarity of current source shows direction of power flow. In this model, control loop need to be switched by direction of power flow. Therefore analyzing and controlling bi-directional DC-DC converter is much easier than conventional way. Seamless dynamic model are derived by state-space averaging method. Analytical, simulated, experimental results are investigated, and availability of seamless model is suggested.