Design of a circumscribing polygon wide bandgap based integrated modular motor drive topology with thermally decoupled windings and power converters

Abstract

In this paper, the design of an integrated modular motor drive topology based on the circumscribing polygon of the outer surface of the conventional cylindrical housing is introduced from the mechanical and the thermal point of view. The design of the shared machine and converter cooling system is optimized from the thermal point of view using computational fluid dynamics (CFD) simulations. A wide bandgap, specifically Gallium Nitride (GaN), based half-bridge converter module is designed and implemented for integration. For a case study of a machine of outer radius 75 mm, axial length 80 mm and six stator modules, the resulted surface area for each converter module is 80*87 mm 2 . The size of the converter module was reduced so as to exactly match the available surface around the machine. A method for the calculation of the maximum power per module is introduced resulting in 1032W per module for the case study considered in the paper. A method for the DC-link capacitor design is introduced and the influence of the stator phases connections on the DC-link current stress is explained. Experimental measurements are done on one segment of the proposed integration topology.

An Integrated Motor Drive with Enhanced Power Density Using Modular Converter Structure

“…• The switch loss that results in 115 • C junction temperature is computed using the CFD model. • From the switch loss versus temperature model developed in [9], the peak winding current that results in the switch loss in step 1 is calculated.…”

“…The most challenging aspects in the design of the integrated motor drives (IMD) are the shared thermal management of the machine and the converter [7], [8] and the small space available for the converter modules [9]. These challenges can be met by utilizing the wide bandgap (WBG) semiconductor switches especially, the Gallium Nitride (GaN) technology thanks to its low losses and small package size for the same voltage and current ratings compared to Silicon devices [3], [10].…”