This paper presents the power electronic platform used for the VSYNC project. In this project, inverters are controlled in such a way as to exhibit a virtual rotational inertia towards the grid, in order to limit grid frequency variations in grids containing a high share of inverter-connected DER. First the layout and operation of the platform are described in detail, showing its versatility for research purposes. Next the performance of the platform is illustrated using experimental results obtaining using a grid-connected inverter in a laboratory setup.Index Terms-Virtual synchronous generator, power electronic converter, rapid prototyping platform, grid-connected inverter, virtual rotational inertia.

Internal combustion engines (ICE) are combined with electric motors and batteries in both hybrid electric vehicles (HEV) and plug-in hybrid electric vehicles (PHEV) to improve efficiency and achieve a limited all electric range. This paper determines the electrical power required for charging a fleet of PHEVs in Belgium. A stochastic model based on the driving behavior of Western European drivers, determines the availability of the PHEVs for grid charging.Three scenarios are defined to generate charging profiles based on the driving profiles. The first two scenarios, defined as uncoordinated charging, are based on a continuation of the current tariff schemes available to residential users, i.e. a single electricity tariff or a double electricity tariff including a day and night tariff. In the third scenario, coordinated charging is proposed. When coordinated charging is applied, the time of charging is shifted to a more appropriate moment of the night where total electrical load is minimal. The charging energy when coordinated charging is applied for each PHEV is defined to be equal to that of the single tariff scenario.The extra load caused by charging PHEVs is added to the residential and industrial electricity consumption of Belgium in 2008. Based on this data, a year load duration diagram can be determined to quantify demand for both power and energy in base load, variable load and peak load. Uncoordinated charging for residential users will cause difficulties for the electricity production system because peak load will rise substantially while base load stays the same. Coordinated charging is essential to minimize the impact on the electricity production system and could be implemented using smart meter technology.

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The aim of this paper is to investigate the impact of the current ripple, originating from the dc-dc converter of e.g. a PHEV powertrain, on the ageing of Li-ion batteries. Most research concerning batteries focuses on very low (µHz) to low (Hz) frequencies and low current ripples to create very accurate battery models which can determine e.g. the State of Charge of the battery. On the other hand the design of dc-dc converters tries to reduce the current ripple by using multiple phases with interleaving technique and capacitors in parallel with the battery. The interaction between the current ripple of the dc-dc converter and the battery has received little attention so far. A test set-up is build with two identical 304 V , 12 kW h Li-ion batteries and two 100 A dc-dc converters. The dc-dc converter can be connected to an LCL-filter or solely to the primary inductor of this filter, such that the battery current contains a small or large current ripple respectively. The batteries are discharged and charged to simulate the circumstances in which a plug-in hybrid electric vehicle is used. After each month, during which the battery either experiences a small or large current ripple, characterization tests are performed to establisch the ageing of the batteries. Based on the test results, the current ripple does not appear to have a measurable impact on the battery resistance and the Discharge and Regen Power. There is an increase of the resistance and a decrease of the Discharge and Regen Power, but this is to be expected as the battery packs are submitted to 3 months of Combined Cycle Life Testing. The temperature of the battery turns out to be far more important for the resistance and attained power levels of the batteries. The absent effect of the current ripple on the ageing of the batteries may be due to the intrinsic double-layer capacitor. This capacitor at the surface of the electrodes carries part of the current ripple and reduces the current ripple as experienced by the actual charge transfer reaction which carries the dc-part of the current.

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