(Invited) High Power SiC Power Processing Unit Development

The NASA space flight program can be divided into manned and unmanned programs with each contributing and ultimately setting the stage for advanced space transportation systems, future space habitats, and spacecraft that can send humans deep into the solar system. Most spacecraft use solar arrays for the main source of power except for those that had relatively short flight duration, or for deep space probes that were designed for very long flight duration. As the vision for space exploration evolves; spacecraft, space stations, and space habitats power needs increase exponentially thus creating the need for more efficient and revolutionary power technologies. NASA is investing in the most cutting-edge power technologies to enable the human space exploration beyond the earth vicinity.

The NASA Human Exploration Framework Team (HEFT) recommended demonstrating Spacecraft buses with increasing power & decreasing specific mass to enable advanced electric and plasma propulsion spacecraft that will decrease trip times to Mars and beyond. Primary or auxiliary electric propulsion systems provide many potential benefits to the spacecraft developer when compared to chemical propulsion systems. The high specific impulse provided by electric thrusters substantially reduces the amount of propellant required to achieve a given mission. This mass savings can be leveraged in many ways including reduction of spacecraft mass, reduced launch vehicle requirements, increased on-orbit lifetime, or increased payload.

Recent advances in solar array technology that produce more efficient and lighter solar arrays have enabled the notion of high power spacecraft as large as 300kW to MW class.  These high power systems will require high power, higher voltage distribution and power converters all requiring high voltage parts. 

In response to these technology needs, NASA GRC has been developing a solar electric power processing unit that would operate from a nominal 300V_DC spacecraft bus.  The unit utilizes 1200V commercial silicon carbide power MOSFETs and high voltage SiC schottky diodes.  This developments main objective is to demonstrate the capability of high power, high voltage, and power processing for a 2000-second specific impulse Hall Effect Thruster.  To date this development has demonstrated the mass and efficiency gains which using silicon carbide at high voltage provides illustrating the need for radiation hardened space rated components.