Fundamental Modeling of the Switching Transition in High-Speed Power Electronics

Abstract

Recent advances in semiconductor technology have paved the way for ultra-fast switching capabilities. This increase in switching speed enhances efficiency, power density, and frequency but also increases overvoltage oscillations at the switching node. Existing methods that effectively suppress this overvoltage include slower switching and minimisation of inductance, but unfortunately, these methods become very difficult to implement as the switching speed increases. A new oscillation suppression method, Zero Overvoltage Switching (ZOS), has previously been developed in which the overvoltage is suppressed very effectively by increasing both the switching speed and inductance, contrary to mainstream expectation. This is the only oscillation suppression method that becomes more effective as the switching speed increases and is not constrained by the minimisation of inductance, yet this method has not gained widespread recognition. This is expected because Zero Overvoltage Switching is not explained within the context of existing knowledge, and the argument for implementing it is difficult in the very narrow window where the advantages outweigh the effort. This research develops a generalised fundamental model to better understand Zero Overvoltage Switching by describing the mechanics of fast and slow switching events. The model is also able to provide insights that lead to methods to apply Zero Overvoltage Switching over a broader range of voltages and currents.

Keywords

• Wide bandgap (WBG)
• ultra wide bandgap (UWBG)
• zero overvoltage switching (ZOS)
• oscillation suppression methods