This paper introduces a promising approach for developing an
integrated traction motor drive based on the Integrated Modular
Motor Drive (IMMD) concept. The IMMD concept strives to meet
aggressive power density and performance targets by modularizing
both the machine and power electronics and then integrating them
into a single combined machine-plus-drive structure. Physical
integration of the power electronics inside the machine makes it
highly desirable to increase the power electronics operating
temperature including higher power semiconductor junction
temperatures and improved device packaging.
Recent progress towards implementing the IMMD concept in an
integrated traction motor drive is summarized in this paper.
Several candidate permanent magnet (PM) machine configurations with
different numbers of phases between 3 and 6 are analyzed to compare
their performance characteristics and key application features. A
6-phase, 10-pole PM machine topology has been selected as the most
promising configuration for meeting the major requirements in the
areas of power density, efficiency, and module count. A parallel
investigation of fault-tolerant distributed control configurations
for the IMMD traction drive has led to selection of a heterarchical
controller configuration that requires each phase module to be
equipped with its own independent microcontroller operating as a
peer with all of the other phase module controllers.
The potential of silicon (Si)-insulated gate bipolar transistors
(IGBTs) operating at junction temperatures up to 200°C has been
evaluated using a hardware testbed in terms of device losses and
thermal issues. Based on these study results, a 10 kW phase-leg
package design using Si IGBTs has been investigated including die
selection, material selection, layout design, parasitic extraction
and thermal characterization. Thermal performance characterization
has been conducted for different packaging structures, operating
conditions and coolant selections. The proposed packaging design
and cooling approach can maintain the Si IGBT junction temperature
below 200°C with an ambient temperature of 150°C.
