Algorithm for histogram based fault detection in a CCS-MLI topology

This paper presents an algorithm based on histogram of the inverter output voltage, to detect open switch fault in cross connected sources based multilevel inverter (CCS-MLI) topology. This topology requires less number of components as compared to classical topologies, but may have chances of switch failure. Here load voltage samples are analyzed using histogram pattern for the detection of fault. For a healthy inverter, the histogram pattern is symmetrical around zero. Each open switch fault changes the voltage sample patterns uniquely to indicate appearance of fault. This method does not require additional components, complex calculations and does not depend on the load and feedback loop.