A Half-Bridge On-State Voltage Sensor for In-Situ Measurements

Current prognostics for life expectancy of power semiconductors utilize off-line measurements of the on-state resistance. Presented is a half-bridge (HB) on-state voltage (VON) sensor capable of being utilized for in-situ measurements enabling continuous and real-time monitoring of the on-state resistance. The design provides a single VON measurement output that contains independent VON information of both high and low side devices in a HB leg. The measurement output is referenced from the middle point of the HB and combines the two complementary VON sensing outputs. This system reduces the number of components, required number of analog signal processing circuits, and ADC channels for in-situ health monitoring of a power electronics system. These reductions will facilitate integration of the VON sensor with the gate driver board and achieve low system profile. The experimental results demonstrate the proposed VON measurements while switching with inductive and resistive loads.