SBIR-STTR Award

In the Phase I effort of this this work, we will conceptualize, design, fabricate and validate through simulation and preliminary experiments of a 8 kW-rated silicon carbide (SiC) based galvanically isolated dual-output bi-directional DC-DC power converter circuit that can operate at a wide range of temperatures in space environments. Moreover, the design comes with a high degree of modularity and configurability of a proposed three-port network, where (a) multiple power converter units can be paralleled on the output side to scale up the power level, (b) planar magnetics technology is employed to enhance the power density and (c) power flow can be directed between any two specific ports while being able to bypass the third port. Furthermore, we plan to fabricate radiation hardened versions of the SiC power devices with high resiliency to heavy ion strikes. Thus, the outcomes of the proposed device technology and its demonstration with the proposed power converter pave the way for advanced, more efficient and lightweight space power systems. The proposed power converter technology: will lead (a) to reducing the weight and volume (both by ~40%) of onboard power electronics through integrating two isolated DC-DC power stages with a projected power density of 1.3kW/L and 2.6kW/kg, (b) incorporating a unique control strategy to enable simultaneous regulated power flow toward both the output ports, while maximizing the converter efficiency not only at full load but also at light loads, (c) bidirectional enabling both DC bus-to-battery (D2B) charging and battery-to-other DC loads (B2D) discharging capabilities, (d) maintaining a rated load efficiency over 96.5% (~2.5% greater than state-of-the-art) across a wide operating ambient temperature range from -70C to 150C, and (e) employing a robust structure of power converter, where the implementation of gate driver and control circuits would be simple, hence leading to improved reliability of the system. Potential NASA Applications (Limit 1500 characters, approximately 150 words): Harsh environment SiC power converters have wide applications in (a) spacecraft power management, (b) DC distribution systems in Venus/Mercury/Mars explorers, (c) motor drives, inverters and power supply derivatives in Space Station, satellite power system, and (d) motor drives in 'more electric' technology applied to aircraft generators and reusable launch vehicles. SiC technology also finds unique applications in harsh environment CMOS-based control, driver integrated circuits and sensors, where Si technology has its limitations. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words): Applications of harsh environment SiC power electronics include (a) power management and distribution system in ground/naval/air military vehicles, (b) automotive engine control electronics, (c) electrical actuator and motors drives in commercial aircraft jet engines, (d) compressor in geothermal, oil & gas extraction, (e) deep-well drilling telemetry module and electric actuation in gas turbines.

The current trend in power electronics is to create a module solution to achieve higher densities and functionality. The advanced current and future NASA missions need more “plug and play” solutions, therefore the concept of combining power electronics modules to create a compact multi-input and multi-output power “box” is becoming the norm in advancing the state-of-the-art. Hence, the goal of this project is to develop multi-port and multi-direction power modules, which are modular / interchangeable and highly efficient, resulting in design flexibility, improved control, as well as weight and volume savings. The project outcomes are also expected to give rise to expanded mission range, expanded operational envelope, and increased prime power for instrumentation and propulsion. The goal is to advance the development of a modular triple active bridge (TAB) DC-DC power conversion interface as part of DC distribution systems or local DC microgrids in international space stations or spacecrafts. Of particular interest is the development of a versatile power module for use in lunar and planetary surface power management and distribution systems. We are targeting to achieve (a) a low weight and thermally efficient compact design, yielding to a gravimetric power density of 6.6 kW/kg and specific power density of 9.15 kW/L, using an efficient design and a high-frequency PCB-wound planar transformer. The proposed novel control and modulation technique is likely to facilitate (a) minimization of conduction and switching losses, (b) loop decoupling to enable simultaneous regulated power flow toward both the output ports, (c) bidirectional power flow enabling both DC bus-to-battery charging and battery-to-other DC loads discharging capabilities, and (d) a high rated load efficiency at full load, and a much higher efficiency compared to conventional TAB converters in light load and non-unity voltage gain operation. Potential NASA Applications (Limit 1500 characters, approximately 150 words): The planned space stations such as Gateway, and the future lunar and planetary surface missions for establishing bases, for example, on the Moon and eventually on Mars, require low mass and high efficiency modular power electronic regulators. The plug-and-play power module units with autonomous smart control schemes similar to those that we build are pivotal to manage and distribute power across a grid such as that needed, for example, at a future lunar base. Such a base requires high power levels and long distribution networks. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words): Applications of harsh environment SiC power electronics include (a) power management and distribution systems in military and commercial vehicles, (b) automotive engine control electronics, (c) electrical actuators and motor drives for aircraft jet engines, (d) compressors in geothermal, oil and gas extraction, (e) deep-well drilling telemetry modules and gas turbine electric actuation systems.