PHIL Testing of a Battery Integrated Multilevel Converter Combining Real and Emulated Modules

This paper presents a Power Hardware-in-the-Loop (PHIL) testing methodology for emulating the different parts of a battery system with modular converters (a multilevel converter) developed in the SEABAT-project. Using PHIL offers significant advantages, such as reducing the risk of equipment damage and personal injury. In particular, the absence of a battery cell is a clear advantage regarding required safety measures. Additionally, it shortens development and testing cycles, as system testing can commence before the final hardware is available. The presented testing approach involves two physical battery modules, each with its real hardware module converters and control systems, but with emulated batteries. The remaining modules of the battery string are emulated using a wide-band power supply controlled by an OPAL-RT real-time simulator. The system also includes physical string controllers and a system master controller, with the string controller somewhat adapted to interface with the real-time simulator. During the PHIL testing phase, numerous minor and major software faults were identified and resolved early in the process. Furthermore, the control functionalities of a hybrid high-energy and high-power battery concept were tested and validated. The primary contribution of this work is the demonstration of integrating real and emulated battery modules with distributed converters within the same string of a multilevel converter in a PHIL test bench. It addresses the challenges and necessary adaptations for such a configuration.