D12.2 - Coordinate-Based Variable-Switching-Frequency PWM Strategy for Parallel Three-Level NPC Converters for Low-Voltage High-Current Applications

Thursday, March 26, 2026

12:00 PM - 1:45 PM CT

Location: Poster 1

Technical Dialogue Presenter(s)

FG

Feng Guo

University of Wisconsin-Milwaukee

Co-Author(s)

KC

Knapoj Chaimanekorn

University of Wisconsin-Milwaukee
RO

Ryan Olson

University of Wisconsin-Milwaukee
Tianchen Li

University of Wisconsin-Milwaukee
RC

Robert Cuzner

University of Wisconsin-Milwaukee
Yue Zhao

University of Arkansas
University of Arkansas

In this digest, a new coordinate-based variable-switching-frequency (VSF) modulation technique is proposed for parallel three-level (3-L) neutral-point-clamped (NPC) converters for low-voltage high-current (LVHC) applications. To achieve a better harmonics profile at the grid side, the interleaved PWM is adopted, resulting in high-frequency circulating current (CC). Hence, to leverage the maximum allowable CCs among parallel-interleaved NPC units, the behavior of CCs is first predicted based on a sextant reference frame. By doing so, three-phase modulation waves can not only be determined without zero-sequence voltage (ZSV) injection, but also the peak value of three-phase CCs can be determined with less effort and high accuracy. Moreover, the capacitor voltage balance is realized by proprietary pulse patterns and dwell-time regulation.