Research and/or Engineering Questions/Objective:

One of the key technologies used in electrified vehicles is regenerative braking, which allows recovering energy during braking phases by using the electric motor as a generator. In this function mode, energy is transferred from the motion of the wheels to an energy storage device such as a battery and hence the vehicle is decelerated. Regenerative braking has notoriously changed the design, integration and testing of braking systems. The development and integration of new testing tools oriented towards the new technology trends emerging is key.

Methodology:

The main objective of this project is the development of a control module to simulate hybrid braking on a brake dynamometer. This control module must provide the core functionalities that allow performing brake applications containing regenerative component.

To achieve the main objective of this project, several specific objectives need to be accomplished:

- Regenerative Braking Capabilities: adapt the Inertia Simulation module to simulate hybrid braking on brake dynamometer.

- Vehicle Testing: obtain relevant regenerative braking data from vehicle testing.

- Validation Tests: validate the developed modules throughout the usage of the data obtained from vehicle testing.

All the stated developments are to be integrated into Applus+ IDIADA's dbDyno brake dynamometer control system.

Results:

The regenerative braking concept to be implemented in brake is based in importing vehicle data and using it as a demand for the brake dynamometers. Additionally, artificial manually generated profiles can also be used.

Having previously developed the Inertia Simulation module simplifies the task of implementing the regenerative capabilities concept. In order to implement regenerative braking capabilities into dbDyno - Control System it is necessary to perform the following steps:

- Integrate Inertia Simulation and Regenerative Braking functionalities within Labview software architecture of dbDyno control system.

- Integrate the developed functionalities into dbDyno's control tasks, more specifically in the brake control phase.

- Modify dbDyno's user interface to incorporate the set of parameters to configure the Inertia Simulation and Regenerative Braking behaviour. These parameters need to be distributed in different parts of the dbDyno software.

- Add the necessary modifications in the physical layer in order to allow communicating dbDyno and the drive units of the electric motors regarding torque control.

To use the regenerative capabilities in a manner that its results are the closest to reality as possible, some regenerative braking characterization data from vehicle testing is obtained. The data is consequently used for validation purposes.

Limitations of this study:

It is important to note that this objective does not include the simulation of regenerative brake logics, as this is not the primary goal for brake dynamometer testing at this stage.

Conclusion:

The project has been successfully concluded, validating brake dynamometer regenerative testing capabilities, using vehicle data testing on proving ground.

Together with that, dynamics of the electric motor must be evaluated in a passenger car brake dynamometer to confirm that the torque profiles obtained from the motor fully match with vehicle profiles. Further tests must be performed but the solutions obtained up to date look promising for current and future applications.

Fabio Squadrani, Senior Manager, Applus IDIADA; Mr. Kenneth Mendoza, Applus IDIADA; Mr. Carlos Sierra, Applus IDIADA; Mr. John O'Leary, Applus IDIADA; Mr. Chris Robbins, Applus IDIADA; Mr. Bernat Ferrer, Applus IDIADA