An Active CM and DM EMI Filter Based on Synthesized and Synchronized Signals for the DC Input of a GaN Inverter

Abstract:
In this contribution, the electromagnetic common- and differential-mode emissions at the input of a GaN-based inverter are actively suppressed by a cancellation system that synchronously injects two artificially synthesized cancellation signals. Due to the periodic operation, the synthesis can be done from a set of sine waves that can be adjusted very precisely in amplitude and phase. The mutual coupling between the injectors is respected and counterbalanced during signal synthesis. Suitable injecting and decoupling circuits are selected and dimensioned for the system. Measurement results show the very high performance of the proposed method for frequencies of up to 30 MHz.