A Wide-Range Input Auxiliary Power Supply Based on Series-Connected SiC MOSFETs for Modular Multi-Level Converter
[Thesis]
Saeed, Muhammad A.
Yao, Xiu
State University of New York at Buffalo
2020
66 p.
M.S.
State University of New York at Buffalo
2020
Auxiliary Power Supply (APS) is required to power the gate drive circuit of IGBT in the Modular Multilevel Converter (MMC). The input voltage of the APS is taken from the DC-link voltage of the submodule capacitor while its output voltage is integrated with the gate drive of the submodule IGBT. Most existing topologies involve a complex circuit design and can only power a single gate drive circuit. This work proposes a novel topology based on single-input multi-output flyback converter with series-connected SiC MOSFETs to power gate drive circuits of both IGBTs inside one submodule. The circuit is designed and the controller is implemented to work with a wide input voltage range while maintaining a constant output voltage. Additionally, pulse transformer and passive snubber schemes are explored to achieve consistent gate signals which avoid the voltage balancing issues in series-connected MOSFETs at the switching transients. In-depth analysis of the proposed topology is presented, along with SPICE simulation verification using models of commercial devices.