NIO Inc.
Power transistor junction temperature determination using a desaturation voltage sensing circuit

Abstract:

A measurement circuit device for a vehicle includes a power transistor and a voltage measurement circuit coupled to the power transistor that measures a voltage across the power transistor. The measurement circuit device also includes a microcontroller that determines a junction temperature using the measured voltage and adjusts a capacity of the power transistor based on the determined junction temperature. In some embodiments, the measurement circuit device may include a clamping device that clamps the voltage across the transistor when the transistor is off. The measurement circuit device may also include an analog-to-digital converter that converts the measured voltage from an analog value to a digital value.