Compound-Semiconductor-Enabled Renewable Energy System for Powering Critical Buildings in Africa

Africa’s power supply systems for critical loads, such as healthcare facilities, are transitioning to a more sustainable, efficient and reliable future. This is driven by the integration of renewable energy, which includes AC and DC power conversion enabled by power semiconductors switching at increasingly high frequencies (e.g., 10–100 kHz). The semiconductors’ operation causes power loss, reducing energy efficiency, and they are the most vulnerable components, counting for 20%–30% of the failure of power conversion systems. Improving the performance of the semiconductors will thus provide significant benefits in energy saving and system reliability improvement. For example, a 1% increase in efficiency in solar photovoltaic (PV) inverters and a 1% in reliability will make 150 GWh more energy available to critical healthcare facilities in Africa. This project’s overarching aim is to leverage the latest advancements in Silicon Carbon (SiC) semiconductor technology to develop high-efficiency and reliable solar photovoltaic-battery energy storage system (PV-BESS) for critical loads. Such compound semiconductors have low conduction loss, fast switching speed, and high operating temperature, which provides all potential for developing low-carbon PV-BESS. Challenges are that high-frequency switching of SiC semiconductors can increase thermal stress and create electromagnetic interference (EMI) due to their high-speed voltage transients (e.g. dv/dt over 10kV/us), affecting the reliability of the PV-BESS and lifespan of critical components such as capacitors and batteries. SiC semiconductors exhibit various material defects and variability, leading to variations and high non-linearities in their electro-thermal performances. Integrating SiC semiconductors into PV-BESS requires a better understanding of induced parasitic parameters and their coupling with components, including capacitors, inductances and gate drivers. To address these issues, the project has three research work packages (WP1-3): Develop accurate characterisation and modelling methods for semiconductor devices (WP1): Accurate SiC electro-thermal models and lifetime models will provide a new understanding of SiC semiconductors, which will be built to evaluate component efficiency and reliability under various environments. Integration optimisation of SiC-based PV-BESS (WP2): This involves studying and modelling the multiphysics coupling between SiC semiconductors and other components, investigation of induced parasitic parameters and system-level topology design of PV-BESS to reduce power conversion stages, thus improving overall efficiency and reliability. Validation and operation optimisation of SiC-based BESS in various operation conditions (WP3): This will investigate integration strategies and verify the benefits brought by SiC devices' advantages to ensuring the BESS’s high-efficiency and reliable operation in both normal and fault conditions. The main deliverables will include validated tools and a testbed for modelling and characterisation of SiC semiconductors (WP1), hardware-in-the-loop demonstrator for validating the SiC-based PV-BESS (WP2), and optimal operation strategies for PV-BESS (WP3). These will be useful to physics R&D institutions, renewable equipment vendors, and power system operators. The project will involve international partnerships with the University of Nairobi, with support from Scottish Power Energy Networks (SPEN) and Toshiba Europe. Researchers involved will benefit from the unique collaboration and training, and the project will help Africa build new physics research capacities in the renewable energy and semiconductor sectors. The project output will boost the PV-BESS’ energy conversion efficiency by 1%–2%, and extend their mean-time-between-failures by 20%. Developed compound semiconductor technologies will have a wider impact across applied industries, including electrified transportation sectors, robotics and aerospace. The integration and BESS technologies can be extended to generic low—and medium-voltage energy systems.