Numerical simulation of surge protection circuits and experimental verification using a lightning surge simulator

With the transformer less direct AC mains rectification adopted in many AC-DC converters for processor based products, many electronic components in off-the-line switchmode power supplies are vulnerable to common-mode transients. With the predictions in the International Technology Roadmap for Semiconductors, VLSI devices are currently progressing towards feature sizes around 22 nm, with sub 1 V DC power supply requirements and equivalent noise voltages close to the DC rail values. These two scenarios make state-of-the-art systems seriously vulnerable to lightning and other power transients, and better transient protection systems are required by the power conversion electronics. In a research project to predict the propagation of transients within the power conversion interfaces, accurate models for nonlinear surge protection devices have been developed. This paper highlights the numerical simulations done with the help of MATLAB to investigate transient propagation through an IEC61000-4-5 specified category “B” protection unit. The accuracies of the simulations are confirmed by experimental validations using a lightning surge generator.