A new high-saturation induction, high-temperature nanocomposite alloy for high-power inductors is discussed. This material has FeCo with an A2 or B2 structure embedded in an amorphous matrix. An alloy of composition Fe56Co24Nb4B13Si2Cu1 was cast into a 1.10in. wide, 0.001in. thick ribbon from which a toroidal core of approximately 4.25in. outer diameter, 1.38in. inner diameter, and 1.10in. tall was wound. The core was given a 2T transverse magnetic field anneal, and impregnated for strength. Field annealing resulted in a linear B-H response with a relative permeability of 1400 that remained constant up to field strengths of 1.2T. The core was used to construct a 25μH inductor for a 25kW dc-dc converter. The inductor was rated for operation in discontinuous conduction mode at a peak current of 300A and a switching frequency of up to 20kHz. Compared to commercially available materials, this new alloy can operate at higher flux densities and higher temperatures, thus reducing the overall size of the inductor.

Bidirectional solid-state circuit breakers (BDSSCBs) can replace mechanical fault protection devices in systems having bidirectional current flow through a single bus, for increased transition speed, functionality, and reliability. Silicon carbide, 1200-V, 0.1-cm 2 JFETs were designed and fabricated for the BDSSCB application. A novel BDSSCB gate driver was developed for both self-triggered temperature-compensated over-current protection, and external triggering. Bidirectional 600-V, 60-A fault isolation was demonstrated in a transition time of approximately 10 µs with two packaged JFET modules, a bidirectional RCD snubber, and a series distribution bus inductance of 20 µH. I.

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This paper presents the relevancy, design, and test results of a 90 kW continuous duty, three-phase, bi-directional, DC-DC converter for hybrid electric vehicles. Nominal low-side and high-side voltages of 320 V and 600 V, respectively, were used. Continuous boostmode operation at 90 kW, and continuous buck-mode operation at 45 kW were demonstrated using 80 ºC (inlet temperature) Castrol 399 oil coolant. The volumetric power density of the three-phase test-bed was 2.7 kW/l in boost-mode at a coolant temperature of 80 ºC. Based on two-phase tests, the power density at a coolant temperature of 25 ºC is projected to be 4.1 kW/l. To increase power level and power density, custom IGBT modules have been built and tested. A design layout for a packaged four-phase converter, using the custom IGBTs, including sensors and control hardware, indicates that a volumetric power density of above 4 kW/l is feasible at an 80 ºC coolant temperature.

A dual 1200 V, 400 A power module was built in a half-bridge configuration using 16 silicon-carbide (SiC) 0.56 cm 2 DMOSFET die and 12 SiC 0.48 cm 2 JBS diode die. The module included high temperature custom packaging and an integrated liquid cooled heat sink while conforming to the footprint and pinout of a commercial dual IGBT package. Die encapsulant was not used, to allow data collection by infrared thermal imaging. The module was DC tested at currents up to 400 A and coolant temperatures up to 100 ˚C. Switching was evaluated in a boost converter at load power levels up to 25 kW and at frequencies up to 30 kHz with coolant temperatures up to 80 ˚C. Acceptable current sharing between MOSFET die was observed over the switching frequency and coolant temperature ranges. Package thermal resistances and MOSFET and diode power losses were characterized. Results were compared to those simulated for a 400 A IGBT module.