To utilize power more efficiently, development continues on various power systems such as Integrated Fight Through Power (IFTP), Electric Drive (ED), and Reconfigurable Zonal Systems. The Solid State Power Substation (SSPS) is a distribution system that is being considered for use. To realize an SSPS, there are a number of technology issues that must be addressed at both the material and component levels.

One of the issues that needs to be addressed involves weight and size. Weight and center of gravity are critical concerns of the next generation power distribution system. The current power generation systems uses heavy, bulky systems placed in areas that are not optimal. One method to reduce the weight and size of the current transformers used in legacy power distribution systems is to use solid state technology (semiconductor components such as transistors and integrated circuits) instead of the heavy iron cores and copper coils. This “solid state transformer” combines power electronics with a transformer that is reduced in size due to the increased operating frequency of the power electronics.

The new Wide Band Gap (WBG) semiconductor materials, principally SiC (Figure 1-1), offer the necessary material properties to address the higher power performance challenges. Continuous power switches, power diodes, and pulsed power switches fabricated from SiC, offer reductions in on-state resistance and switching loss over conventional silicon power devices. For a given power rating, these components can operate at a higher duty cycle, leading to a reduction in the size of inductors and transformers in power circuits. SiC power electronics also extends solid state technology by offering higher breakdown voltage levels than current silicon technology, to address voltage levels presently managed by electromechanical switch technology.

WBG semiconductors represent a possible paradigm shift in semiconductor power density. WBG devices operate at higher temperatures and require less cooling. The higher blocking voltages and lower switching loss at high frequency of SiC devices, as compared to silicon devices, allow for the use of smaller transformers and inductors. Improved thermal management of semiconductors and passive components through upgraded packaging would allow more current to be handled by a given device and lead to improved power density designs.

Power conversion equipment developed using SiC technology is projected to significantly reduce the workload and maintenance requirements. Use of SiC power conversion technology will reduce the current power conversion equipment size by approximately 60%. There will also be a weight savings approaching 2.68 tons for each converter implemented with the new technology.

To realize the potential of high power SiC devices requires a packaging technology that is beyond present industry standards. Current power electronics packaging cannot meet the Department of Defense (DoD) metrics for High Power Electronics. The EMPF is undertaking this ManTech project to develop a high temperature packaging technology and demonstrate its reliability in high power devices/modules (Figure 1-2).

Both Powerex Inc. and the EMPF are developing screening tests and manufacturing processes that will allow high voltage packages to operate at higher temperatures. In parallel with these developments, Penn State ARL will validate the reliability of the package. Successful testing of these modules will lead to the design and fabrication of additional components by the DoD.