An advanced active rectifier based on the single-star bridge cells modular multilevel cascade converter for more-electric-aircrafts applications

An increasing interest is currently verified in DC power distribution systems for the More-Electric-Aircrafts (MEA). DC power distribution enables a more efficient use of the generated power and aids in paralleling and load sharing. Transformer Rectifier Units (TRU) and Autotransformer Rectifier Units (ATRU), commonly employed to date, are heavy to be deployed in a MEA because the power to be handled is much higher than in a conventional aircraft. This is particularly applicable in case variable frequency generators are used since it is not possible to synchronize their outputs directly. In this paper an advanced active rectifier is proposed for MEA applications. It is based on a Single-Star Bridge Cells Modular Multilevel Cascade Converter (SSBC MMCC) combined with Dual Active Bridge (DAB) DC/DC converters in order to create a DC Multibus. The performances of the system are analyzed considering different load configurations and variable frequency operation. Results confirm the validity of the proposed solution and the robustness of the control system in different operating conditions.