Working at Green Transportation Drive and High Efficiency Energy Conversion Research Center, focusing on solid-state transformers including isolated dc-dc converters and medium-frequency transformers. - Developed a 3600V/20A SiC MOSFET power module using quasi-series connection based on a hybrid clamping topology, with an open-loop modulation scheme which guarantees voltage self-balance under any load currents. The module features low switching losses and low dv/dt as well.- Built a 160kVA/5.5kHz traction transformer with 85kVac insulation, which is 50% less in loss and size compared to industry prototypes in China, and a 43kVA/50kHz transformer achieving 40kW/L power density. Proposed a general leackage inductance model and optimization for wired medium-frequency transformers. - Proposed advanced modulation schemes for dual-active bridges for better transient performances, e.g. overshoots, dc-biases and all-region ZVS. - Proposed several soft-switching, high-gain converters for PV and fuel cell applications.

STATCOM under virtual synchronous machine control- Developed the virtual synchronous machine (VSM) control scheme for STATCOM operation with a design guidline, achieving 10% voltage variation compared to traditional control ;- Assessed the control scheme in both small-signal and large-signal senses;- Built a scaled-down prototype for experimental verification.Analysis on interactions between STATCOMs with impedance-based stability criterion- Evaluated multiple-STATCOM operation in proximity for the first time;- Developed a dq-frame impedance model for general grid-tied converters;- Analyzed interactions between STATCOMs using impedance model, achieved accurate predictions of stability and pinpointed the cause of instability;- Constructed a scaled-down micro-grid with Si- & SiC-based converters for experimental verification, with the usage of the world's only impedance measurement units.

Worked as an intern in the Electric Transmission Operation Research group.Evaluated the operation of Dominion's four STATCOMs distributed in a concentrated area:- Conducted N-1 fault analysis of the reduced transmission grid in PSCAD- Explored the effects of STATCOMs' control settings and control modes- Found potential negative interactions due to control settings- Submitted results to Grid of The Future

Worked in Power Electronics and Motor control System Institute, Department of Electrical EngineeringA Hybrid Cascaded Multilevel Bidirectional Converter for Battery Storage Control;· Devised a converter for battery storage control based on the multilevel converter proposed by Professor Fangzheng Peng and Leon Tolbert· Designed an algorithm to initiatively manage charge and discharge of batteries with multilevel strategy· Implemented the converter with DSP· Modularized storage units and the controller, granting the system flexibility for different applications