Condition Health Monitoring of Modular Multilevel Converter Submodule Capacitors

With a large deployment of power electronic converters in various critical applications, condition health monitoring is increasingly becoming important. In modular multilevel converter, submodule capacitors represent one of the critical components having a strong impact on the overall converter cost and performance. This article proposes a simple method for the submodule capacitance monitoring, deployed directly on the low-cost submodule controller and operating without disturbing or impacting the normal converter operation. Offline and real-time simulations, as well as experimental results, demonstrate the effectiveness of the proposed method in identifying changes in the submodule capacitance, which is of high importance for reliable converter operation.