In this paper a test set-up for bidirectional charging will be introduced. This set-up offers the

flexibility to evaluate different interfaces of grid operators, battery electric vehicles, charging

stations, energy management systems or other components in a set-up with a power and

communication flow. In addition to this it offers a testing possibility of new charging strategies

which then can be transferred to the real world. Also, an example of a control mechanism will

be shown in the paper to show the functionality of the test set up.

Introduction and Motivation

Testing bidirectional vehicles and charging stations is essential to ensure the reliability, safety,

and efficiency of the rapidly evolving electric vehicle (EV) ecosystem. Bidirectional vehicles,

which support vehicle-to-grid (V2G), vehicle-to-home (V2H), or vehicle-to-load (V2L)

technology, have the unique ability to both draw power from the grid for charging and return

stored energy back to the grid or home. Bidirectional charging involves complex interactions

between different components and systems, including vehicles, charging stations, and grid

infrastructure. Testing ensures compliance with local, national, and international regulations

and promotes interoperability between different manufacturers’ equipment. To reach this goal

a test set-up to evaluate the compliance with different components like an energy management

system (EMS), a charging backend system or with different vehicles or charging stations is

introduced and developed.

Applied Method

In the first part literature research was conducted to identify all necessary components to

emulate a charging station or a vehicle. In addition to these requirements, additional functional

requirements were set. After all requirements were set the conceptional design of the test set-

up was executed. Therefore, a charging controller with the open-source software stack

EVerest was choosen. EVerest offers an open-source implementation of the ISO 15118-2

and -20. The ISO 15118-20 is a main requirement for bidirectional charging. The resulting

architecture was then translated to a laboratory test set-up with the possibility to put different

vehicles, charging station or other systems in the test loop. Afterwards the compliance with

different charging stations and vehicles was tested. Then a control mechanism was evaluated.

The evaluated control mechanism was a bidirectional power control based on the voltage of

the grid. To evaluate this control strategy a grid simulator with a grid emulation of a low voltage

grid was used.