Design of Sensors for Real-Time Active Electromagnetic-Emission Control in SiC Traction Inverters

Abstract:
This paper presents a set of sensors that estimate voltage and current slopes as well as the switching overshoot amplitudes of a wide-bandgap (WBG) traction inverter. The information can be used to adjust the gate voltage to regulate the electromagnetic emissions of an inverter. Passive, PCB integrated probes are attached to the MOSFETs and provide voltage signals proportional to the derivatives of uDS and iD. These time derivatives are filtered by means of a passive network, that creates a low pass or band pass filter to distinguish between frequencies relevant for overshoot or transition slopes. The filtered signal is processed by a set of amplifiers and a sample-and-hold circuit to prepare for sampling by the driver’s analog-to-digital converter. The sensors are implemented in a three phase 800 V silicon carbide (SiC) traction inverter. The measurement results prove the feasibility of the sensors and provide an input for future intelligent gate control applications.