A Reliable Photovoltaic Inverter Using A Fault Tolerant Algorithm And A TRIAC System

Reliability is one of the critical factors in solar power generation systems. In photovoltaic systems, system reliability depends on the performance of power converting circuits, which are affected by power metal-oxide semiconductor field-effect transistors (MOSFETs). These MOSFETs experience open circuit (OC) and short circuit (SC) faults during operation that cause significant damage to inverter operation and the entire system\u27s performance. Addressing OC and SC faults, this thesis proposes a method that uses inverter half-cycle approximation. This half-cycle approximation uses an algorithm that combines changes in inductor current and respective changes in output voltage to classify possible faults in the power MOSFETs. Also, a redundant switching system is added to the original inverter to make the inverter operation more reliable during post fault conditions. This method locates the faults along with fault classification and alters the switching pattern in the entire topology within 1 to 2 switching cycles after the fault detection. The proposed operation is explained under OC and SC power MOSFET failure conditions and validated through simulation results. This fault-tolerant technique provides a quick response during post-failure conditions along with multiple switching patterns for redundant topology switches