Identifying natural degradation/aging in power MOSFETs in a live grid-tied PV inverter using spread spectrum time domain reflectometry

Spread spectrum time domain reflectometry (SSTDR) has been applied to a live PV inverter circuit to measure impedance variations caused by natural degradation in switching devices (MOSFET), and this method was applied without altering the normal operation of the circuit. Therefore, the proposed technique is able to perform condition monitoring - the state of health of the inverter. The experimental results and the corresponding analysis have been included which show that it is possible to determine the various path impedances inside a PV inverter using SSTDR, and thereby, it is possible to detect any natural degradation associated with the power semiconductor devices inside the circuit.