Abstract
Characterizing the switching losses of wide bandgap semiconductor devices requires wide bandwidth measurement equipment with the smallest possible insertion inductance added to the commutation path by the current sensor. A common current measurement approach is using low-cost off-the-shelf SMD resistors and measure the voltage drop. This SMD shunt approach has a limited bandwidth due to parasitic inductances. In this work, an evaluation of such a low-cost current shunt is performed. The influences and constraints that limit the bandwidth are investigated. The design of a compensation network and the resulting bandwidth improvement are examined. Based on the theoretical discussion, a compact current shunt is designed, that allows a simple integration into the commutation path while adding a low insertion inductance. The measurement results show, that the common measurement approach can reach a bandwidth of several hundred MHz if the design constraints are met and can be further extended by a compensation network.
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