The common mode (CM) voltage generated by a switching power converter yields unwanted currents to circulate in the ground paths, tripping ground faults relays, accelerating motor bearing aging, and producing electromagnetic interference (EMI). Typical differential mode (DM) models of power converters do not account for CM paths and currents, so models including parasitic components and CM voltages must be used to predict CM EMI. In this presentation CM modeling and analysis will be highlighted and popular CM EMI mitigation methods, including passive filters, active filters, and novel power converter topologies will be briefly summarized.
The second part of the presentation will focus on novel CM voltage elimination methods based on a game-changing shift from pulse width modulation (PWM) to pulse density modulation (PDM) for grid-forming and grid-following inverters. Rapid prototyping of three-phase four-leg inverters, built with wide bandgap devices (WBG), will also be presented to demonstrate the elimination of the CM voltage at the switching frequency and significantly reducing the size of the CM passive filters required to meet the conducted emission limits in MIL-STD-461G.
Speaker(s): Dr. Giovanna Oriti,
Virtual: https://events.vtools.ieee.org/m/329518