Eladio Clemente Delgado

Low inductance power module with blade connector

A novel single-switch power module has been developed, featuring a laminated blade connector for low inductance interconnect to a busbar. The module was designed, optimized and experimentally validated as part of a high frequency three-phase converter, demonstrating parasitic inductances of less than one nano henry for the module and as low as five nano henries for the converter phase-leg commutation loop. The flexible plug-in hardware facilitated direct comparison of switching performance between three different chipsets, including a 150A and a 300A hybrid designs using the fastest 1200V silicon IGBTs with silicon carbide (SiC) Schottky diodes, as well as a 150A all-SiC module with emerging SiC MOSFETs. The results were also compared with switching performance of standard modules. First, the impact of parasitic inductance on switching performance was quantified by testing the same 300A hybrid chipset in an industry-standard module. Compared to the low inductance blade POL module, the standard module had 65% higher voltage overshoot and 30% higher total switching losses. Second, the switching performance of the 150A, 1200V fast IGBT, in either standard silicon or the hybrid blade module, was compared with the all-SiC blade module under the same test conditions. The IGBT switching losses of the standard silicon module were 3.5 times higher, while the hybrid blade module losses were 2.5 times higher than those of the all-SiC module. The new low inductance blade module is an excellent package for the new generation of fast silicon IGBTs and the emerging SiC power devices. The module will enable efficient power conversion at significantly higher switching frequencies and power densities.

Performance and Reliability of SiC MOSFETs for High-Current Power Modules

We address the two critical challenges that currently limit the applicability of SiC MOSFETs in commercial power conversion systems: high-temperature gate oxide reliability and high total current rating. We demonstrate SiC MOSFETs with predicted gate oxide reliability of >106 hours (100 years) operating at a gate oxide electric field of 4 MV/cm at 250°C. To scale to high total currents, we develop the Power Overlay planar packaging technique to demonstrate SiC MOSFET power modules with total on-resistance as low as 7.5 m. We scale single die SiC MOSFETs to high currents, demonstrating a large area SiC MOSFET (4.5mm x 4.5 mm) with a total on-resistance of 30 m, specific on-resistance of 5 m-cm2 and blocking voltage of 1400V.

100 Amp, 1000 Volt Class 4H-Silicon Carbide MOSFET Modules

The development of large area, up to 70m/1kV (0.45cm x 0.45cm) 4H-SiC vertical DMOSFETs is presented. DC and switching characteristics of high-current, 100Amp All-SiC power switching modules are demonstrated using 0.45cm x 0.225cm DMOSFET die and commercial Schottky diodes. The switching performance from room temperature up to T=200°C of the All-SiC modules is presented, with as much as ten times lower losses than co-fabricated Si-based modules using commercial IGBTs.

Miniature Piezo Composite Bimorph Actuator for Elevated Temperature Operation

Development of a new, miniature actuator with large stroke and enhanced thermal stability could provide an improved capability for useful applications. This paper investigates the design, fabrication and testing of a macro fiber composite (MFC) based bimorph actuator to meet stringent requirements such as size, stroke and thermal stability. Results indicate that a d33 /d31 MFC configuration was compact and provided sufficient stroke while avoiding issues related to depolarization at elevated temperature. A compact, high voltage power supply that runs off of a 3 volt battery was also developed as part of this effort.Copyright

High performance two H-bridge in cascaded gradient driver design with SiC power MOSFET

In this paper, a detailed high efficiency two H-bridge in cascaded gradient driver design with 1700V SiC MOSFET is presented. Both module and system level stray inductance are minimized to better utilize the SiC high switching speed capability. The amplifier loss is calculated in simulation with device loss model and also verified in hardware experiment. The efficiency of the amplifier is higher than 99%. Higher output ripple frequency (up to 125 kHz) provides the opportunity to design a high density output filter without magnetic components. A novel ripple current cancellation circuit (RCCC) with embedded coolant pipe is also presented and demonstrated.

Low-Ripple Low-Transition Time, Current Driver for Large Inductive Loads

The paper presents a precision current driver for electron-beams steering coils. The proposed current driver provides an effective solution to the applications requirements: fast current changes in the coil inductor and very accurate low-ripple steady-state current (<0.06%), together with high power density. The power converter circuit is based on the use of two operating voltage levels. A high voltage is used for a fast transition to the required current level, and a low voltage is used to provide steady state precise regulation with low current ripple. The paper presents a solution using two voltage supplies that requires only one high frequency switching device, and also proposes alternative circuit solutions that require only a single input supply and generate internally the required voltages as part of the normal circuit operation. The experimental results to verify the correct circuit operation were obtained on a prototype built with low conduction loss IGBTs, a MOSFET for high frequency switching, and SiC diodes that allow minimal perturbation when transitioning from high voltage to low voltage