Our group is working to demonstrate high-efficiency power converters using new wide-band-gap semiconductor devices and integrated cooling to reach very high power densities.

In a system level, we developed microfluidic cold plates that were attached to 20 GaN power transistors to cool a 2.5kW multi-level converter. A small thermal resistance of 0.2 K/W was measured at a flow rate of 1.2 ml/s and a pressure drop of 600 mbar. Experimental results show a 10-fold increase in power density compared to conventional cooling. This offers a new thermal-management approach to achieve more compact and efficient power converters.

To demonstrate the potential of embedded cooling in a semiconductor device, we monolithically integrated a full-bridge rectifier onto a single GaN-on-Si die. Rectification was provided using four high-performance tri-anode Schottky barrier diodes with a breakdown voltage of 1.2 kV and high-frequency capability up to 5 MHz. To fully benefit from the compactness of high-performance microchannel cooling, a three-layer PCB with embedded coolant delivery channels was developed and used to guide the coolant to the device. 

Another example of high power density converter was demonstrated through a full-scale optimization of a kilowatt-range megahertz-class boost converter based on the impulse rectification, proposed by our group.

To increase its power density, the entire power stage and for high efficiencies over wide frequency ranges, high-performance gallium nitride transistors are employed and various high-frequency materials (MnZn, NiZn, and air) with different geometries are compared to realize a wide-bandwidth inductor. The optimized converter enabled a peak efficiency of 98.6% along with an ultrahigh power density of 52 kW/l (850 W/in3). 

Relevant publications:

1. R. Van Erp, R. Soleimanzadeh, L. Nela, G. Kampitsis, E. Matioli, “Co-designing electronics with microfluidics for more sustainable cooling”, Nature, 2020
   
   

2. R. v. Erp, G. Kampitsis and E. Matioli, “A manifold microchannel heat sink for ultra-high power density liquid cooled converters,” 2019 IEEE APEC, Anaheim, CA, USA, 2019
   
   

3. G. Kampitsis, R. v. Erp and E. Matioli, “Ultra-High Power Density Magnetic-less DC/DC Converter Utilizing GaN Transistors,” 2019 IEEE APEC, Anaheim, CA, USA, 2019
   
   

4. R. Van Erp, G. Kampitsis, E. Matioli, “Efficient microchannel cooling of multiple power devices with compact flow distribution for high power-density converters” IEEE Transactions on Power Electronics, 2020
   
   
5. A. Jafari, M. Samizadeh Nikoo, R. van Erp and E. Matioli, “Optimized Kilowatt-Range Boost Converter Based on Impulse Rectification With 52 kW/l and 98.6% Efficiency,” IEEE Transactions on Power Electronics 2021