Brian Rowden

High-temperature silicon carbide and silicon on insulator based integrated power modules

This paper presents the challenges and results of fabricating a high temperature silicon carbide based integrated power module. The gate driver for the module was integrated into the power package and is rated for an ambient temperature of 250 °C. The power module was tested up to 300 V bus voltage, 160 A peak current, and 250 °C junction temperature.

High voltage, high power density bi-directional multi-level converters utilizing silicon and silicon carbide (SiC) switches

This paper presents a bi-directional ac-dc isolated converter designed to be utilized within the US Navys Integrated Fight Through Power (IFTP) concept. To demonstrate the proposed approach the authors have designed, fabricated, and tested a 20 kW power conversion module (PCM) prototype. The fabricated PCM module was used to demonstrate the proposed overall electrical design approach, high-frequency isolation, bi-directional power flow and soft-switching operation of the quasi-resonant topologies. Moreover, the 20-kW prototype allowed the verification of control methodologies as well as magnetic and thermal designs, and provides a test bed for future, higher power work.

High Temperature SiC Power Module Packaging

Wide band gap semiconductors such as silicon carbide (SiC) provide the potential for significant advantages over traditional silicon alternatives including operation at high temperatures for extreme environments and applications, higher voltages reducing the number of devices required for high power applications, and higher switching frequencies to reduce the size of passive elements in the circuit and system. All of these attributes contribute to increased power density at the device and system levels, but the ability to exploit these properties requires complementary high temperature packaging techniques and materials to connect these semiconductors to the system around them. With increasing temperature, the balance of thermal, mechanical, and electrical properties for these packaging materials becomes critical to ensure low thermal impedance, high reliability, and minimal electrical losses. A primary requirement for module operation at high temperatures is a suitable high temperature attachment technology at both the device and module levels. This paper presents a transient liquid phase (TLP) attachment method implemented to provide lead-free bonding for a SiC half-bridge power module. This module was designed for continuous operation above 250 °C for use as a building block for multiple system level applications including hybrid electric vehicles, distributed energy resources, and multilevel converters. A silver-based TLP system was used to accommodate the device and substrate bond with a single TLP system compatible with the device metallurgy. A SiC power module was built using this system and electrically tested at a 250 °C continuous junction temperature. The TLP bonding process was demonstrated for multiple devices in parallel and large substrate bonding surfaces with traditional device and substrate metallization and no requirements for surface planarization or treatment. The results are presented in the paper.Copyright

Spray Cooling Development Effort for Microgravity Environments

Spray cooling is a high heat flux removal technique considered for systems such as advanced lasers and high power density electronics. Several experiments have been conducted using spray cooling in recent years and various designs of spray cooling devices are continually emerging. At this time, one of NASA’s missions is to enhance future space science capabilities through the application of power lasers and electronics. However, the usage of systems having high heat fluxes can only be achieved with the corresponding development of high power thermal control systems. For the reliable performance of these high‐heat‐flux systems, proper thermal management is imperative. The study presented reviews the fabrication of a spray cooling system aimed at addressing issues pertinent to space applications. These issues include heat flux capability, orientation, and volumetric packaging. Computer modeling of spray cooling under microgravity conditions as well as comparison to the analogous 1‐g condition was also perfo...

A Three-Level Full-Bridge Zero-Voltage Zero-Current Switching Converter With a Simplified Switching Scheme

This paper presents a simplified switching scheme enabling zero-voltage and zero-current switching of all the main power devices of a three-level full-bridge dc-dc converter. It also describes the main operational modes and design equations of the converter. Simulation and experimental results demonstrate the feasibility of the proposed ideas. Multilevel dc-dc converters making use of high frequency transformers are suitable for integration in solid-state solutions for application in electric power distribution systems.

Packaging and characterization of silicon carbide thyristor power modules

The need for high-voltage power semiconductor devices in utility applications ranging from isolating faults within a quarter cycle and efficient use of renewal energy resources is rapidly growing. To this end, silicon carbide thyristor power modules were fabricated and characterized electrically. In particular, three SiC thyristors were attached on a common direct bond copper substrate with a copper heat spreader to form a power module. Series resistances were inserted to achieve a good matching of their on-state currents. Experimental results revealed that this power module offered good thermal matching for parallel operation.

Double sided spray cooled bi-directional power conversion module

In this work, a power conversion module (PCM) was packaged and integrated with a double-sided spray cooling system developed to demonstrate vertical thermal management system integration. The parallel design of the power electronics and thermal management system provide the capability for high power density. The spray cooling system designed provides capability for relatively large areas with heat fluxes above 50 W/cm2 using a dielectric fluid like FC72trade.