Major Publications & Ongoing work
Currently, my research focuses on:
a) Design of GaN-based highly efficient isolated and grid-connected singe and three phase solar micro-inverters.
b) Design and development of hardware and software protection schemes for grid-connected solar micro-inverters.
c) Modeling and control of power electronic systems.
d) Model predictive control theory and its real time applications in SiC and GaN-based power-electronic systems and networks.
e) Design of active gate drivers for SiC based WBG power electronic systems.
Some of the journal publications authored along these lines and ongoing work are shown :
- Grid connected single and three phase converters, hardware development and control design
Differential-Mode Three-Phase Ćuk Inverter
"Control of Isolated Differential-Mode Single- and Three-Phase Ćuk Inverters at Module Level''
IEEE Transactions on Power Electronics
About the paper: Differential-mode Ćuk topology provides a non-linear input output gain, and hence an adaptive Lyapunov based non-linear control law has been designed to stabilize the converter.
Three phase voltages and currents for three-Phase Ćuk inverter
Adaptive non-linear control law definition for the highly non-linear three-Phase Ćuk Inverter
2. Switching sequence based control for wide band gap power electronic systems
"Switching-Sequence Control of a Higher-Order Power-Electronic System Driving a Pulsating Load'
IEEE Transactions on Power Electronics
About the paper: Using optimal control theory and stability bounded switching sequences, challenging naval pulsating loads are stabilized and DSP computation time reduced.
Hardware Power electronic system (PES) set-up to test Switching-Sequence Control laws on pulsating naval loads
Switching-sequence Control laws stabilize pulsating naval loads on a non-minimum phase PES
Switching-Sequence Control laws come up with a stable range of control actions based on extensive offline analysis
"EMI Mitigation of a Ćuk Based Power-Electronic System using Switching-Sequence-based Control"
IEEE Transactions on Power Electronics
About the paper: Using the EMI peaks of a PES as constraints in the switching sequence based control scheme, the control mitigates EMI autonomously and reduces common-mode and differential-mode EMI filter size.
Challenges in EMI filter design that impedes high frequency operation in WBG set-ups.
Hardware PES set-up with dual-core DSP
Hardware PES set-up to perform EMI testing according to EMI testing standards (CISPR/EN 55022/32 Class A and Class B)
Autonomous EMI mitigation using control
Invented a dual-mode control architecture to mitigate common-mode EMI
Ongoing work for future publications
3. Design of an switching transition control scheme to shape device transitions
About the work: An active gate drive-based switching transition control (STC) scheme for a Cree SiC high-power module. Based on an efficiency target, the STC network modifies the turn-on/turn-off times of the SiC device to achieve the target. The STC network is based on switched resistor methodology, where GaN-FET based switches S1 and S3 operate at over 20 MHz to control the transitions of the main SiC device.
The fabricated active gate driver achieves PES efficiency targets
Experimental set-up to test the active gate drive based PES
Edge transition control
4. Cascaded operation of differential mode inverters, flexible transformers
Input series output series inverters
Input series output series ac/ac converter control system design for input voltage equalization
Input series output series ac/ac converters (solid-state transformers)
Experimental results for input voltage equalization
