Evaluation of Current Measurement Accuracy for a Power Module with Integrated Shunt Resistors

Abstract

Measurement of the output current of voltage source inverters is often needed for control and overload detection. The integration of shunt resistors in power modules represents a simple, cost-effective and compact solution for this task. Challenges that have to be addressed with this approach are the trade-off between power losses and the amplitude of the sense voltage, voltage isolation, measurement tolerances and inductive coupling effects. In this paper, a standard 17 mm module with integrated shunt resistors is presented together with a delta-sigma modulator for isolation and analog-to-digital conversion. The measurement accuracy is evaluated by simulations and measurements.