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

In this paper, an integrated motor drive with modular converter structure is analysed with different number of converter modules per phase. The integration concept is realized by designing a housing structure with a flat outer surface and a circular inner surface with a cooling channel in between. The converter modules are mounted on the outer flat surface and the stator components are attached to the inner surface. This integration topology is applied on a fifteen stator coil concentrated winding permanent magnet axial flux machine. The converter modules are implemented as half-bridge inverter using Gallium Nitride (GaN) technology. The cooling structure is optimized using computational fluid dynamics (CFD) simulations. The maximum thermally safe current that can be injected by one inverter module is computed. The maximum winding current is also calculated. Parallel connection of the inverter modules is suggested to maximize the thermal utilization of the windings while keeping the inverter switches junction temperature under the rated value. The CFD based computations are validated with experimental measurements.