Synthesis of an Optimized Control Signal for an Improved EMC Switching Behavior of MOSFETs Using a System Characterization Approach

Active gate control of MOSFETs is a common strategy to improve efficiency and/or electromagnetic compatibility (EMC) of power electronic systems. Finding an appropriate control method for specific requirements is no trivial task, and often there is a trade-off between efficiency and EMC. In this paper, a novel method is proposed that utilizes synthesized control signals. With signal synthesis methods, that can be realized affordable in future integrated circuits, signal shapes can be adjusted more or less arbitrarily. Various requirements, e.g. switching waveforms, overall system's EMC or efficiency, can be aimed at this way. Here, a basic MOSFET circuit is investigated which should generate a specific switching waveform. This waveform shall improve the system's EMC without significantly affecting the efficiency. The system is developed, characterized and a mathematical approximation is derived that respects the important temperature dependency. In this first demonstration, very low switching frequencies are considered that make the reactive elements of the MOSFET negligible. From the requirements and the system model, a suitable control signal can be derived. Measurement and simulation results show the good performance of the proposed method.