Reliability assessment of photovoltaic quasi Z-source inverter through stochastic modeling

Reliable operation of power electronic converters is a critical issue since all power generation industries involve them. So many stress causing factors such as temperature, environment, humidity, vibrations, etc., may affect the performance. Such failures or hazards happening in a single component or a small subsystem may affect the entire operation. Any photovoltaic (PV)-based system have two major units: Solar panel and power conditioning unit (Inverter). Most of the times, PV panels do not cause system unavailability or system shutdown. This results in increased maintenance cost and down time of system. So, it is significant to analyze how far a system is reliable by various reliability metrics. In this work, a photovoltaic-based five-level Quasi Z-Source Inverter is taken into consideration for system availability computation. The proposed system is modeled using Markov’s reliability model which is a stochastic model. The entire system has been broken to three subsystems namely PV panel, Quasi Impedance Network and H-bridge. The state transitions of the subsystems were analyzed, and the system availability is computed using 5th order Runge—Kutta method. A hardware model of the proposed system is developed, and the Markov’s states are validated.