Online Measurement of Rise and Fall Times in SiC MOSFET-Based Inverter Output Voltage

A novel detector circuit designed to precisely measure rise and fall time in the output voltage of SiC-based inverters is presented in this paper. Such measurements are crucial for dead-time compensation applications and active gate driver methods. The proposed detector circuit comprises two major blocks: input attenuators and voltage transition sensing unit. A hybrid configuration of resistive and capacitive dividers is utilized in the input attenuators to effectively handle the diverse frequency range of SiC-based inverter output voltages. In the voltage transition sensing unit, high-speed comparators compare the attenuated inverter output voltage with two reference signals. The rise and fall times are evaluated by analyzing the output voltages of these comparators. Additionally, the paper provides an in-depth analysis of the theoretical foundations related to the transient times of inverter output voltage. A crucial aspect of the research involves comparing the measurement results obtained from the detector circuit with those acquired using an industrial differential voltage probe. This comprehensive analysis aims to validate the precision of the proposed detector circuit in analyzing the voltage characteristics of SiC MOSFETs, thereby contributing valuable insights and advancements to the field.