Decoupling of interaction between WBG converter and motor load for switching performance improvement

Abstract

High speed switching of WBG devices causes their switching behavior to be highly susceptible to the parasitics in the circuit, including inductive loads. An inductive load consisting of a motor and power cable significantly worsens the switching speed and losses of SiC MOSFETs in a PWM inverter. This paper focuses on the motor plus power cable based inductive load, and aims at mitigating its negative influence during the switching transient. An auxiliary filter is designed and inserted between the converter and inductive load so that the parasitics of the load will not be "seen" from the converter side during the switching transient. Test results with Cree 1200-V/20-A SiC MOSFETs show that the proposed auxiliary inductor enables the switching performance with a practical inductive load (e.g., motor plus cable based inductive load) to exhibit behavior close to that when the optimally-designed double pulse test load inductor is employed.

Design and Analysis of GaN-based DNPC Converter for Electric Traction Applications

“…11. As expected, according to [12], highly inductive loads could negatively impact the power converter's efficiency due to prolonged reverse conduction. However, it remains higher than 94% under moderate inductive loads, and it approaches 97% under conditions of predominantly resistive loads, even for modest current amplitudes.…”