GaN Optical Isolation for Wide Bandgap Power Electronic Systems (GR-10-07)
Principal Investigators: Dr. Alan Mantooth, Dr. Enrico Santi
There is a need for switching power semiconductor devices that can operate at high voltages, at high temperatures, and at high switching frequencies with low losses. Switching power semiconductor devices fabricated from a wide bandgap material such as SiC or GaN can outperform conventional silicon devices, due to material property advantages. One common problem in grid-connected applications is the need to provide high-voltage isolation of gate drives, while still operating efficiently at the high switching frequencies and high temperatures enabled by wide bandgap devices. This includes optical supply of gate control energy, optical switching of gate potentials, and optical feedback of sensed quantities such as main switch current. Thus protection and current sensing capabilities are an integral part of the proposed interface. The optical coupling was realized using GaN devices that provide superior speed, efficiency and voltage-isolation capability. An additional advantage for GaN power devices is that the proposed drive can be technologically compatible with GaN processes used for power device fabrication, so that eventually a monolithically integrated GaN power device with an optically isolated drive can be realized. This project was funded jointly by GRAPES and an NSF Fundamental Research Grant.