Design of an Integrated DC-Link Structure for Reconfigurable Integrated Modular Motor Drives

In this article, a dc-link structure feasible for integration with the circumscribing polygon modular integrated drives is proposed. The proposed dc-link structure combines both the dc-link capacitors and the bus-bar together and integrates them with the machine and the converter modules without increasing the outer diameter of the integrated machine/converter structure. A generic design methodology for the proposed dc-link structure is provided and applied on a reconfigurable 15 stator coils concentrated winding axial flux machine for all its possible phase configurations. The design methodology presented in this article involves the determination of the required dc-link capacitance and the multiphysics design of the bus-bar. The parasitics of the bus-bar part of the proposed dc-link structure are evaluated using electromagnetic finite element method (FEM) models and their influence on the dc-link waveforms is evaluated. Due to the expected high ambient temperature inside an integrated drive, electromagnetic and computational fluid dynamics (CFD) models are developed for the proposed dc-link structure to evaluate the loss density and the temperature distribution of the bus-bar to ensure reliable operation. An experimental setup is built to validate the design methodology.