500W GaN-based ac/ac solid state transformer (ac/ac) Altium prototype with OC/ UV and OV protection
First Generation Board with integrated protection features
Hardware prototype tested up to 500 W with fully functional protection features
Cascaded operation of differential mode converters were explored for a project funded by DOE. Various cascading configurations namely input series output series (ISOS), input series output parallel (ISOP), etc. were experimentally validated and control algorithms were developed for equal voltage and current sharing across the modules. Effects of communication delay and failures were also investigated.
500 W grid connected GaN-based DMCI solar micro inverter Altium prototype with integrated protection circuit
Second generation board with integrated protection features
Hardware prototype tested up to 500 W with fully functional protection features. The gate drive was made isolated to improve gate loop design, and to positively affect low-cost sensed resistor based OC protection features
500 W Grid Connected GaN-based DMCI Solar micro inverter driven by custom made control card and TMS320F28335 DSP
500 W Grid Connected GaN-based DMCI Solar micro inverter driven by custom made control card and dual-core launchXL
Custom made control card to interface with digital signal processors. The board houses analog and digital isolation stages for protection and noise decoupling and common mode noise rejection
Fabricated control card. The control card serves as an interface between the power stage and industrial processor
Active gate driver to perform switching transition control of SiC Mosfet (Cree QPM3 1.7 kV module) transitions and acts as a replacement for Cree based fixed gate drive
Hardware implementation of the active gate drive based STC network for experimental verification
Cree gate drive to control SiC half bridge module. The gate driver used fixed resistances in the turn-on and turn-off paths.
Cree gate driver (CGD15HB62LP) was modified to control Cree QPM3 1.7 kV half bridge module actively. The gate driver used switched gate drive approach in the turn-on and turn-off paths, thereby improving flexibility. It positively affected overall converter efficiency and EMI
A 2nd generation active gate drive card. The card can be used to control Cree QPM3 1.7 kV half bridge module and also Cree CAS325M12HM2 1.2 kV module. Compared to the Gen-1 board, the board has been designed to attain several switching transitions of the gate resistance during a turn-on/turn-off event. It uses EPC8004 40 V, 4 A GaN-FETs (<370 pC Qg), and LMG1020 ultra-fast gate drivers from Texas Instruments to have precision control of the edges.