FPGA Implementation of a General Space Vector Approach on a 6-Leg Voltage Source Inverter

A general algorithm of a Space Vector approach is implemented on a 6-leg VSI controlling a PM synchronous machine with three independent phases. In this last case, the necessity of controlling the zero-sequence current motivates the choice of a special family of vectors, different of this one used in Pulse Width Modulation (PWM) intersective strategy and in common Space Vector PWM (SVPWM). To preserve the parallelism of the algorithm and fulfill the execution time constraints, the implementation is made on a Field Programmable Gate Array (FPGA). Comparisons with more classical 2-level and 3-level PWM are provided.Fui8 within the SOFRACI projec

Modeling of Hydro-Pneumatic Energy Storage Using Pump Turbines

Modelling of a hydro-pneumatic energy storage system is presented in this paper. Hydro pneumatic storage aims to combine the good efficiency of hydraulic energy conversion and the space flexibility of pneumatic storage. The project aims to model a prototype which uses a rotodynamic multi-stage pump-turbine to displace a virtual liquid piston to compress air. To facilitate mass and heat transfers between both phases, there is no separation between the water and the air. A dynamic model of the storage system is developed using block diagram methodology. It takes into account characteristic curves of the pump-turbine and thermodynamic equations. Modelling results show that vapour diffusion contributes to reducing compression final temperature. This implies an increase of storage efficiency. A test rig construction will begin at the end of autumn 2011. It will be electrically connected to the “Distributed Energies” platform of ‘’Arts et Métiers Paristech’’ in Lille.adem

Simplified converters models for the analysis and simulation of large transmission systems using 100% power electronics

In this paper, a model order reduction method is proposed, to simplify power electronics converters and allow simulating large transmission systems using 100% power electronics. Unlike existing methods it keeps the system's physical structure, thus making the simulation and the analysis more flexible. This method is validated on a two-converter system and proves to be both conservative and accurate

Model reduction of converters for the analysis of 100% power electronics transmission systems

Because of the fast development of wind and solar photovoltaic power plants, as well as the multiplication of high voltage direct current links, the analysis and simulation of large transmission systems with a high penetration of power electronic converters have become necessary. In this situation, reduced models of converters are needed to make the simulation faster and the stability analysis more straightforward. These reduced models need to be accurate enough, depending on the needed accuracy, and they have to keep the physical structure of the converter full model to be easily implemented on classical analysis software. A structure-preserving method to reduce the state order of a grid forming converter model is presented here. It is based on a modal analysis to remove the fastest poles of the system while keeping the slowest almost unchanged

A priori error estimation of the structure-preserving modal model reduction by state residualization of a grid forming converter for use in 100% power electronics transmission systems

This article deals with the model order reduction by state residualization of power electronic converters. It presents a method to a priori estimate the error induced by this reduction. This method helps choosing the most suitable reduced model, the one that minimizes the error, depending on the simulated events. When applied to a system with several converters, it helps choosing which converter to reduce and how much, in order to simplify the models while keeping a sufficient accuracy

MMC Stored Energy Participation to the DC Bus Voltage Control in an HVDC Link

The modular multilevel converter (MMC) is becoming a promising converter technology for HVDC transmission systems. Contrary to the conventional two- or three-level VSC-HVDC links, no capacitors are connected directly on the dc bus in an MMC-HVDC link. Therefore, in such an HVDC link, the dc bus voltage may be much more volatile than in a conventional VSC-HVDC link. In this paper, a connection between the dc bus voltage level and the stored energy inside the MMC is proposed in order to greatly improve the dynamic behavior in case of transients. EMT simulation results illustrate this interesting property on an HVDC link study case

Emission Reduction and Economical Optimization of an Urban Microgrid Operation Including Dispatched PV-Based Active Generators

In order to take full advantage of distributed generators, an evolution of the classical power system organization and management is also necessary. An aggregator of a residential urban electrical network can be considered by the distribution system operator as a stakeholder, which is able to control a cluster of local generators and loads with technical constraints for the connection with the remaining distribution grid and commercial contracts with outer electrical producers. This paper is focused on the design of the microgrid central energy management system which relies on a day-ahead operational planning and an online adjustment procedure during the operation. A dynamic programming-based algorithm is derived to solve the unit commitment problem with a multiobjective function in order to reduce the economic cost and CO2 equivalent emissions. The proposed energy management system is implemented into a supervisory control and data acquisition (SCADA) and tested by using a hardware-in-the-loop simulation of the urban network. Economic and environmental gains are evaluated

Inferring site function and technological organization from combined spatial, technological and microwear-analyses at the Mesolithic wetland site of Kerkhove-Stuw, northwestern Belgium (preliminary results)

The extensive Mesolithic site of Kerkhove-Stuw was located on the top of a natural levee,adjacent to a palaeochannel of the river Scheldt. Subsequently (from the boreal onwards),the landscape was covered by approximately 4,5m to 9m of peat and alluvial clay. The infillof the palaeochannel deposits were studied by means of a high-resolution multi-proxy analysis(i.e. pollen, microcharcoal, loss on ignition, magnetic susceptibility, granulometry, molluscfauna ...etc.) to reconstruct the varying ecological settings of the prehistoric occupation.The excavations yielded thirteen spatially distinct concentrations of lithic artefacts thatcould be dated to the Early, the Middle and the Late Mesolithic, based on typology. Thiswas partly confirmed by 14C-dates on single entity charred hazelnut shells. Additionally,the site had great potential for a comprehensive technological analysis thanks to the overalllow-density of the lithic concentrations and the diversity of macroscopically discernable rawmaterial categories.Besides lithics, a considerable amount of unburnt and burnt bone fragments, and palaeob-otanical remains were documented. The preservation of a faunal assemblage (dominated byroe deer and wild boar, but also comprised of fur animals and fish remains) is exceptionalfor the Early and Middle Mesolithic in the region and will allow us, for the first time, to gaina better understanding of Mesolithic subsistence practices.Finally, to determine the inter- and intrasite functional properties and aspects of the tech-nological organization of the thirteen lithic concentrations, the spatial distribution of thedifferent types of material remains are studied, combined with a technological and microwearanalysis of the lithic artefacts. For example, the location of ten possible surface hearths couldbe derived from heavily burnt lithic artefacts and burnt organic remains. So far, preliminary results from the technological analysis indicate the presence of several expedient technolo-gies, more elaborate opposed striking platform knapping sequences and a possible diachronicevolution in preferential raw material use. Both spatial analyses and lithic technology arereinforced by an extensive microwear analysis that can specify the objectives of the knappingsequences and mostly the spatial organization of the different activities (butchery, hide andplant scraping, osseous tools manufacturing...) for each occupation phase.In the future, the results from Kerkhove will have to be compared with those previouslyobtained with the same protocol from other (dryland) sites in northwestern Belgium

Laboratory-based test bed of a three terminals DC networks using power hardware in the loop

In this paper a three stations MTDC grid is presented, providing a specific application of our work. The experimental platform is intended to combine electrical power components and communication/control equipment with real-time simulation tools. In this way the platform can test grid elements and evaluate different operation scenarios under various conditions

Numerical Aspects and Performances of Trajectory Planning Methods of Flexible Axes

Adequate Path Planning design is an important stage for controlling flexible axes because it may allow to cancel vibrations induced by oscillating modes. Among bang-bang profiles which are linked to optimal control, jerk assignment (acceleration derivative) and input shapers have been investigated. Theoretical results show the performance and robustness with respect to natural frequency mismatch. Practical validations on a real robot arm show the relevance of the jerk algorithm which is more robust with the same productivity performances as input shaping techniques