A Bridge-Level Junction Temperature Estimation Method for SiC MOSFETs Combining Transient Voltage and Current Peaks

Accurate measurement of the junction temperature T-j is crucial for ensuring safe operation and evaluating the performance of silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs). In this paper, the junction temperature of a half-bridge is monitored by combining transient voltage and current peaks across the lower device. Both theoretical analysis and switch tests validate that the peak induced voltage and peak reversed current during the commutation transient exhibit a linear relationship with the temperature of the corresponding devices. The impact of load current and bus voltage on the measurement results is also investigated. Moreover, the effectiveness of the proposed method is confirmed by carrying out tests at different temperatures, and the feasibility of online implementation is discussed. The experimental results show that the proposed method has high linearity and sensitivity and can simultaneously provide temperature information for both devices of a half-bridge.