J. Büscher

Electric Vehicle Charging in an Office Building Microgrid With Distributed Energy Resources

This paper discusses the charging of plug-in hybrid electric vehicles (PHEVs) in an existing office building microgrid equipped with a photovoltaic (PV) system and a combined heat and power (CHP) unit. Different charging strategies and charging power ratings for workplace charging are examined for their grid impact and their impact on the self-consumption of the locally generated electricity. The grid impact can be significantly reduced by using strategies that require limited future knowledge of the EV mobility behavior and limited communication infrastructure. These strategies allow a high number of EVs to be charged at an office building, even with a limited number of charging spots, due to the large standstill times.

Impact of Electric Vehicle On-Board Single-Phase Charging Strategies on a Flemish Residential Grid

This paper quantifies the impact of single-phase on-board charging strategies for electric vehicles (EVs) in a case study of a heavily loaded unbalanced Flemish three-phase low-voltage residential grid. Voltage droop charging and EV-based peak shaving, which do not need communication with the distribution grid, are modeled and the results are compared. The grid voltages are analyzed according to the probabilistic and deterministic limits of the EN50160 standard, for a 100% EV penetration rate. The impact on the EV user comfort is evaluated in terms of charging time and electrically driven distances. The chosen voltage droop charging eliminates critical voltages below 0.85 pu and reduces voltage unbalance, with a limited impact on the total charging time. EV-based peak shaving makes the grid fully compliant with EN50160 and avoids the need for an infrastructure upgrade. The electrically driven distances are not influenced by the charging strategies.

Apartment Building Electricity System Impact of Operational Electric Vehicle Charging Strategies

This paper discusses the charging of multiple plug-in hybrid electric vehicles (PHEVs) in an apartment building, equipped with a photovoltaic (PV) system. Different charging strategies and charging power ratings are examined, which are assessed in terms of their grid impact, the self-consumption of local electricity generation, and the electric driving range. The impact of a residential building, which incorporates electric vehicle (EV) charging, on the distribution grid can be significantly reduced by using simple EV charging strategies. These strategies include complementing night-time with day-time charging, peak shaving at vehicle level, and charging the surplus of local generation. Effective results are obtained using only the knowledge of the present battery state of charge, next departure time, and the instantaneous local generation surplus. The simultaneity of the EV charging and the PV production increases. The increase in electric driving range is negligible for three-phase charging.

Early onset of ground state deformation in neutron deficient polonium isotopes

In-source resonant ionization laser spectroscopy of the even-A polonium isotopes (192-210,216,218)Po has been performed using the 6p(3)7s (5)S(2) to 6p(3)7p (5)P(2) (λ=843.38  nm) transition in the polonium atom (Po-I) at the CERN ISOLDE facility. The comparison of the measured isotope shifts in (200-210)Po with a previous data set allows us to test for the first time recent large-scale atomic calculations that are essential to extract the changes in the mean-square charge radius of the atomic nucleus. When going to lighter masses, a surprisingly large and early departure from sphericity is observed, which is only partly reproduced by beyond mean field calculations.

Magnetic Dipole Moment of 57,59Cu Measured by In-Gas-Cell Laser Spectroscopy

For the first time, in-gas-cell laser spectroscopy study of the (57,59,63,65)Cu isotopes has been performed using the 244.164 nm optical transition from the atomic ground state of copper. The nuclear magnetic dipole moments for (57,59,65)Cu relative to that of (63)Cu have been extracted. The new value for (57)Cu of mu((57)Cu) = +2.582(7)mu(N) is in strong disagreement with the previous literature value but in good agreement with recent theoretical and systematic predictions.

Design Criteria for Electric Vehicle Fast Charge Infrastructure Based on Flemish Mobility Behavior

This paper studies the technical design criteria for fast charge infrastructure, covering the mobility needs. The infrastructure supplements the residential and public slow charging infrastructure. Two models are designed. The first determines the charging demand, based on current mobility behavior in Flanders. The second model simulates a charge infrastructure that meets the resulting fast charge demand. The energy management is performed by a rule-based control algorithm, that directs the power flows between the fast chargers, the energy storage system, the grid connection, and the photovoltaic installation. There is a clear trade-off between the size of the energy storage system and the power rating of the grid connection. Finally, the simulations indicate that 99.7% of the vehicles visiting the fast charge infrastructure can start charging within 10 minutes with a configuration limited to 5 charging spots, instead of 9 spots when drivers are not willing to wait.

Voltage droop charging of electric vehicles in a residential distribution feeder

Uncoordinated charging of electric vehicles may cause significant voltage deviations in some residential distribution grids. Grid voltage stabilizing load models, such as developed for distributed energy resources, can be applied to electric vehicle chargers as well. A fleet of 10 electric vehicles is considered, modeled according to current Flemish mobility behavior. For this fleet, different voltage droop load models for the chargers are discussed in terms of charging duration increase, grid losses and grid voltages. Load flow simulations are performed for a real and highly loaded residential grid in Belgium. In the worst case, the average charging rate is reduced to 0.847 pu of the nominal charging rate (4 kW). Accordingly, regardless of charging coordination, deviation from power set points will occur, thereby mitigating the impact on the grid. Furthermore, electric vehicle chargers equipped with voltage droop load models present robust, fault-tolerant behavior at times the coordination of the vehicles is hampered.

Shape isomerism at N=40: Discovery of a proton intruder state in Co67

The nuclear structure of 67Co has been investigated through 67Fe beta-decay. The 67Fe isotopes were produced at the LISOL facility in proton-induced fission of 238U and selected using resonant laser ionization combined with mass separation. The application of a new correlation technique unambiguously revealed a 496(33) ms isomeric state in 67Co at an unexpected low energy of 492 keV. A 67Co level scheme has been deduced. Proposed spin and parities suggest a spherical (7/2-) 67Co ground state and a deformed first excited (1/2-) state at 492 keV, interpreted as a proton 1p-2h prolate intruder state.

Shape Isomerism at N = 40: Discovery of a Proton Intruder in 67Co

The nuclear structure of 67Co has been investigated through 67Fe beta-decay. The 67Fe isotopes were produced at the LISOL facility in proton-induced fission of 238U and selected using resonant laser ionization combined with mass separation. The application of a new correlation technique unambiguously revealed a 496(33) ms isomeric state in 67Co at an unexpected low energy of 492 keV. A 67Co level scheme has been deduced. Proposed spin and parities suggest a spherical (7/2-) 67Co ground state and a deformed first excited (1/2-) state at 492 keV, interpreted as a proton 1p-2h prolate intruder state.

Structure of Co-65,Co-67 studied through the beta decay of Fe-65,Fe-67 and a deep-inelastic reaction

The neutron-rich isotopes {sup 65,67}Fe and {sup 65}Co have been produced at the LISOL facility, Louvain-La-Neuve, in the proton-induced fission of {sup 238}U. Beams of these isotopes have been extracted with high selectivity by means of resonant laser ionization combined with mass separation. Yrast and near-yrast levels of {sup 65}Co have also been populated in the {sup 64}Ni+{sup 238}U reaction at Argonne National Laboratory. The level structure of {sup 65}Co could be investigated by combining all the information from both the {sup 65}Fe and {sup 65}Co{beta} decay and the deep-inelastic reaction. The {sup 65}Fe, {sup 65}Co, and {sup 67}Fe decay schemes and the {sup 65}Co yrast structure are fully established. The {sup 65,67}Co level structures can be interpreted as resulting from the coexistence of core-coupled states with levels based on a low-energy proton-intruder configuration.