NVH Optimization of Range Extender Engines by Electric Torque Profile Shaping
Range extender operation in an electric vehicle should be imperceptible to the driver from a noise/vibration standpoint. Rolling torque compensation allows virtually vibration-free range extender engine operation by utilizing a balanced counter-rotating inertia that is geared to the cranktrain. The combustion process results in engine torque fluctuations that could cause gear rattle in such a system due to a combination of torque reversal and lash in the geared connection. This brief paper addresses the problem of gear rattle in a rolling torque compensation system. First, a preloaded split gear is introduced as a potential mechanical solution to eliminate the clearance in the gear contact zone. In addition, an approach for a mechatronic solution involving active shaping of the generator torque is introduced. This methodology includes measurement of the combustion engine torque via cylinder pressure indication data, calculation of allowable torque limits, and the determination of a generator torque profile to address gear rattle. A multicriteria cost function is introduced to determine the optimal torque within the established constraints. Variations of the cost function are investigated with respect to their impact on efficiency and range extender acoustics.
Chancen und Herausforderungen der Elektromobilitaet / Chances and challenges of electric mobility
Elektromobilitaet ist der Kernhebel zur nachhaltigen Gestaltung des Verkehrs, da im Vergleich zu anderen Antriebstechnologien je nach der Art der Stromherstellung die Effizienz deutlich hoeher und die Emissionsbelastung durch Treibhausgase, aber auch lokale Emissionen wie SO2, NOx oder Laerm, deutlich niedriger sind. Dabei ist fuer den Markterfolg die Lithium-Batterie die Schluesseltechnologie. Sie muss hinsichtlich Kosten, Energiedichte, Gewicht, Lebensdauer und Ladegeschwindigkeiten noch deutlich verbessert werden. Hohe Rohoelpreise gegenueber niedrigen Strompreisen sind ebenfalls fuer den Markterfolg der Elektromobilitaet wichtig. Weiterhin muss eine Beladungsinfrastruktur aufgebaut werden. Aufgrund der Kosten der Ladeinfrastruktur und der Fahrzyklen wird die Beladung ueberwiegend zu Hause oder im halb-oeffentlichen Bereich stattfinden, oeffentliche Ladesaeulen oder Batteriewechselsysteme werden das Angebot wahrscheinlich nur ergaenzen.Die Elektromobilitaet befindet sich derzeit in einer Hype-Phase und einige Marktpenetrationsszenarien scheinen zu optimistisch. Interessante Erstmaerkte fuer Elektrofahrzeuge liegen derzeit bei Pedelecs und Elektrorollern sowie Kleinwaegen fuer Berufspendler. (A) ABSTRACT IN ENGLISH: Electric mobility is pivotal to a sustainable transport system since, depending on the type of electricity generation used, its efficiency is much higher and its emissions of greenhouse gases, but also local emissions like SO2, NOx), or noise, are much lower than with other drive technologies. The lithium battery technology holds the key to market success. This still has to be markedly improved with regard to cost, energy density, weight, lifespan and speed of charging. In addition, a charging infrastructure has to be developed. Based on economic efficiency and driving cycles, charging will mainly be done at home or in semi-public places; public charging stations or battery exchange systems will probably only supplement the services offered. Electric mobility is currently undergoing a lot of hype and some market penetration scenarios seem to be over optimistic. Interesting first markets for electric vehicles at the moment are pedelecs and electric scooters as well as small cars for commuters. (A) Plenarvortrag zur 4. VDI-Tagung Baden-Baden Spezial "Elektrisches Fahren machbar machen", Baden-Baden, 13. und 14. Oktober 2010. Siehe auch Gesamtaufnahme der Tagung, ITRD D368423.
Simulation and control of hybrid renewable energy system connected to the grid
This paper presents a control and simulation of hybrid renewable energy system connected to the grid. The studied system includes a photovoltaic panel, synchronous permanent magnet generator based wind turbine, and a battery for storage energy. The PV array and wind systems are connected to the common DC bus by a boost converter. The battery is connected by a bi-directional DC/DC converter, and then integrated into the AC utility grid via a common DC/AC inverter. In order to extract the maximum energy, a simulation study has been carried out according to the meteorological conditions (wind speed and variable solar irradiance) while maintaining power quality at a satisfactory level. In order to capture the maximum power, a MPPT algorithm is applied for both wind turbine and photovoltaic panel. The modeling and simulation of the whole system has been performed under Matlab/Simulink environment. The obtained results show that the current and the voltage of grid side are sinusoidal and alternative forms, and the power injected to the grid is around the power produced by the hybrid system.