Reliability Analysis and Cost Optimization of Parallel-Inverter System

As the penetration of renewable energy resources proliferate, inverters have been employed as interface in distributed power systems. To achieve expanded power level and system redundancy, parallel connection of inverters has been widely used. This paper derives mathematical models to quantitatively evaluate the reliability of parallel inverters under different topologies and control strategies. A framework to determine the number of inverters in parallel in terms of reliability and cost optimization is proposed. Sensitivity analysis is carried out to identify the impact of parameter variation on system reliability and total cost. At last, power densities of different structures are analyzed for a fair comparison.