Electro-thermal Trade-off for AC-Current Injection & Series-Clamping-Diodes Based R_ds-on Estimation Circuit

Series double diode (SDD) configuration with ac current injection allows online estimation of on-state resistance without the need for current measurement. However, challenges arise from the high-frequency ac current injection, which requires minimizing the ac current-loop inductance while maintaining thermal balance among the diodes. Experimental results demonstrate the negative impact of poor thermal or electrical design on measurement accuracy. Therefore, this paper investigates the trade-off between the ac current-loop inductance and diode-temperature balance in the electro-thermal design of an SDD configuration for power-device health monitoring. The study emphasizes the need for an optimized electro-thermal design to achieve accurate monitoring and estimation of power device parameters.