Development of a power-stage of a bidirectional on-board charger based on wide band-gap semiconductors

The effects of global warming and the impact of fossil fuels have incremented the research and development of renewable energy sources and the management of it. Transport sector is affected by this situation and its electrification is going to be a key factor in the energy transition. On this scenario, systems with bidirectional power flow capability are necessary to consume, store and supply energy. Electric vehicles (EV) are going to be used in transportation and energy storage applications in order to be used as a back-up system for the electrical grid. The on-board charger (OBC) is the device used for the connectivity between the grid and the vehicle. Nowadays, EV include an unidirectional OBC for charging the inlet battery. However, automotive manufacturers are beginning to develop bidirectional solutions in regard of the new electrical horizon. FICOSA, a Tier 1 manufacturer, in its Electromobility business unit, there is interest in developing new OBC solutions and technologies. The expected power demands and voltage levels for the up-coming EVs require the use of new materials. Since the past recent years, wide band-gap (WBG) semiconductors have appeared to be a better solution than solid-state and silicon (S)i switches for power converters. Their power capabilities, voltage level, switching frequencies, thermal and switching losses make them an interesting alternative. Consequently, this project is focused in the development of a power-stage application for an OBC, the ac-dc power factor corrector (PFC) converter using WBG semiconductors. Based on this premise, this document includes an extended analysis and justification of the importance of EV and OBC; making an overview of OBC. Then, the design of the PFC converter is started by a topology analysis and selection for the converter, resulting a tote-pole (TP) structure. Therefore, operation control modes and other improvements to the converter are studied. This, results in the development of the control structure to ensure an appropriate operation in both bidirectional power flows. There, the modulation strategy proposed in this project is a new approach to the Hybrid-PWM (HPWM) existing one, presenting remarkable improvements for a bidirectional TP structure, as simulations show. Finally, the study of this Matser’s thesis includes the development of the hardware of the PFC converter where the circuits are designed and WBG switches are used. This results in the design and fabrication of a prototyping board. Future works will focus on the development of the software system and the validation of the converte