Gate Drives generating EMI in the absence of Power Converter loading

This paper shows how a power converter can generate electromagnetic interference (EMI) through the operation of gate drives only - in the absence of any power conversion. This is due to parasitic capacitances connecting the power semiconductor’s gate to the main circuit. A half bridge converter is used to illustrate this concept. Practical measurements are compared to simulations for an energized and non-energized converter. Even without loading, a converter can exceed regulatory conducted emission EMI limits. This effect is important to consider during the design of converter EMI mitigation - especially for low power converters where the load current is not dominant.