Juan Van Roy

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.

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.

Ideas for Tomorrow: New Tools for Integrated Building and District Modeling

The energy systems in our buildings and building districts form a tight network of several energy sources, such as renewables and fossil fuels, and energy flows, such as electricity and heat. Over the years, the integration and interaction of these sources and flows have become more and more interwoven.

Power electronics for electric vehicles: A student laboratory platform

This paper presents a laboratory platform used in a problem solving and design course for first year engineering master students at the KU Leuven. The platform implements three power electronic systems that are found in electric vehicles: a field oriented controlled motor drive capable of regenerative braking, a bidirectional DC-DC converter and a battery charger. The battery charger is implemented as a bidirectional single phase grid-tied inverter that enables vehicle-to-grid support. Students learn to understand the hardware and control systems in simulation models. Afterwards they can test their models on real hardware through a rapid prototyping platform. The platform has a motor test bench to emulate driving conditions and regenerative braking. Measurable grid voltage deviations are observed while using the grid-tied inverter, demonstrating the impact of electric vehicles on the residential distribution grid.

Development of an open-source smart energy house for K-12 education

Energy consumption in buildings represents about one-third of the world-wide energy consumption. Consumers often are not fully aware of energy-conserving measures they could take. Intelligent control of the heating and lighting systems in buildings is one way to increase energy-efficiency. Children and young adults influence domestic energy consumption, by using appliances such as TV and lighting. Often, they are not aware of the costs incurred. The goal of this research is to develop a educational platform for energy efficiency education aimed towards the full age range of K-12 education. A scaled model of a house is used, to explain the energy flows in the residential setting, well-known by the target audience. A model house is designed, with actual loads, using an Arduino Uno electronics platform as an interface to a PC. A reference program in the integrated development environment S4A allows visualizing the energy consumption in a simple manner. The children control a number of scaled household appliances interactively. A survey with the first 25 children (aged 10-12) suggests higher awareness of energy consumption.

Developing engineering-oriented educational workshops within a student branch

The development of two educational workshops, one on energy efficiency and one on human-machine interfaces, is detailed and discussed. Attraction to engineering is not created as much as lost at early ages through current education methods. Through positive, hands-on experiences with engineering in K-12 education, this trend can be turned. IEEE student branches have as part of their mission the education and creation of quality educational resources for the public. After searching in vain for suitable inexpensive material, the IEEE student branch Leuven decided to design and create two workshops on engineering topics for an audience of 10-12 year olds. Handling this as a repeatable project, the student branch found partners to create a low budget project for the attendees. Using the skillset of the specific partners and organizers optimally on the subtasks, a successful repeatable cooperation is realized. This paper discusses the environment in which the project is realized, the steps to it, and how it (indirectly) benefits the organizing student branch.

Component improvements in the electrification of passenger vehicles drivetrains

In this paper, possible efficiency improvements of electric components used in drivetrain technologies for passenger vehicles are examined. The fuel consumption is determined for drivetrains with various degrees of electrification, combined with a set of combustion engine technologies. The simulations underline the importance of the energy efficiency of the electric drivetrain to obtain low CO2 emissions. The results help in deciding for which components the research has to focus on regarding efficiency improvements. A large sensitivity to total energy efficiency is observed for the electric motor, battery and power electronics efficiencies.