For this Small Business Innovation Research (SBIR) program Iris Technology proposes the Scalable, High Power Cryocooler Controller. The CCE will be optimized to provide power to large space cryocoolers capable of producing cooling of 0.3W at 10K and 0.2W at 4K. Iris is using the Lockheed Martin Space (LMS) Advanced Technology Center Mega Compressor as the target device.
A number of innovative techniques to the CCE design are planned to achieve a target goal of 85% efficient production of 800 watts of cooler power. Two primary innovations are being applied to the power stages. The first is dynamic current balancing power slice architecture. This architecture uses a number of lower power slices that work together to provide the output power. The use of these slices reduce input and output capacitor requirements and allows the use of much smaller inductors, while synchronous operation increases efficiency, reduces power losses and eases thermal requirements, simplifying high power generation.
The other innovation is the use of GaN FETs in the power stages in place of MOSFETs. The GaN FETs can switch more than 10 times as fast as MOSFETs, therefore capacitor and inductors values can be further reduced by another factor of 10 making the design even more space and power efficient.
The objective is to develop a CCE design for high power, high efficiency cryocooler electronics compatible with the LM Mega Compressor. The design will include dynamic current balancing power slice architecture along with high speed GaN FETs to provide power and size efficiency. The CCE design goal is 85% power efficiency, with a low noise profile.
NASA seeks improvements to multistage low temperature spaceflight cryocoolers. Coolers are sought with the lowest temperature stage in the range of 4-10K, with cooling power at the coldest stage larger than currently available, and high efficiency. Desired cooling power is application specific, but two examples are 0.3W at 10K and 0.2W at 4K. Devices that produce extremely low vibration at frequencies below a few hundred Hz are of interest. System/component level improvements that improve efficiency and reduce complexity & cost are desirable.
Outside of international space agencies (i. e., ESA, JAXA, et al.) there is not likely to be significant demand for high cooling power at these levels.