ISOP DC-DC converters equipped 5-level unidirectional T-Rectifier for aerospace applications

This paper deals with Input-Series Output-Parallel (ISOP) DC-DC converters to be used for capacitors voltage balancing in the 5-level unidirectional T-Rectifier for electric generating applications. The proposed generating unit is intended for aerospace applications, to this purpose the power electronic converter configuration is able to supply power to the electric loads at different voltage levels. The 5 level T-Rectifier output at ±270V feeds the ISOP DC-DC converters which output terminals are used to supply the 28V circuitry. Two different control strategies for the whole system are proposed, discussed and verified. First proposed architecture considers the AC-DC and DC-DC as coupled from the control point of view, introducing then the Couple Balancing Control Strategy (CBCS). A comparison is performed with respect to a completely decoupled regulation algorithm, where the AC-DC and DC-DC control loops are not nested, resulting in the Decoupled Balancing Control Strategy (DBCS).