High-Power Density DC-DC Converter for More Electric Aircraft

Abstract

Nowadays, the large dependency of the current society of the non-renewable energies is encouraging the acceleration of the climatic change, which is having a considerable impact on the environment. Consequently, an impulse of the renewable energy consumption (photovoltaic, eolic, tidal, etc.) is being produced. This fact does not only affect to the main forms of electric power generation, but also has an impact on the main users of non-renewable energies. In this context, the automotive sector is one of the principals affected, in which the traditional propulsion method based on fossil fuels is being replaced by partially or totally electric thrust vehicles. Since H2020 started, two new concepts regarding the aeronautic transport where launched: More Electric Aircraft (MEA) and All Electric Aircraft (AEA). In this kind of aircrafts, the Electric Power Distribution System (EPDS) is divided into AC/DC and DC/DC energy conversion. In this work, the DC/DC EPDS proposed for the electric aircraft are analyzed in detail, aiming to deepen into the knowledge of the most employed Power Electronic Converter (PEC) topologies. In these EPDS, the most utilized PEC according to literature proposals is the DualActive-Bridge (DAB) converter. This PEC is formed by two full bridges, interconnected by a power transformer, which can act as inverter and/or rectifier, giving bidirectionality to the system power transfer. As an alternative to DAB converter, Active-Bridge-ActiveClamp (ABAC) has been also proposed, whose primary side is identical to DAB. However, low-voltage side is modified by dividing the full bridge into two half-bridges to include clamp capacitors and output filter DC inductors. To evaluate the scenarios that encourage the utilization of these topologies, the analytical models that describe the voltage and current behavior of the components that are included in these converters are developed in this work. Furthermore, the operating regions while working with the main modulation methods are presented. Once the analytical models are obtained, a brute force-based optimization algorithm is developed that allows to analyze the utilization of different semiconductor, heatsink, magnetic devices and/or capacitor technologies. Then, the evaluation of the impact of these component technologies on the efficiency and volumetric power density of the converter is performed.