Heat flux sensor for power loss measurements of switching devices

The measurement of the power dissipated by a semiconductor device is of great importance for assessing system performance and reliability and to evaluate the overall efficiency of a power electronics systems. Efficiency measurement can be difficult when the device is highly efficient and the power losses are extremely low. Measurement errors can be introduced due to high frequency components in the waveforms. We present a calorimetric method based on a micromachined dual-sensor heat-flux measurement device that allows the estimation of the power dissipated by a semiconductor device. The system use a thermoelectric heat pump to keep the switching device at room temperature in order to minimise the heat exchanged with the ambient and improve therefore the precision of the measurement.