Optimal Sizing of PV-Diesel-Battery System Using Different Inverter Types

Different inverters types have different technical specifications and costs which contribute to the changes of inverter type decisions. It is therefore important to know which inverter is more advantageous for certain criteria. In this paper, the central, string, multi-string, and AC module types of inverters were compared through optimally designing a DG-PV and DG-PV-battery system of an off-grid island using each type of inverter. The problem was solved as a multi-objective optimization considering cost and uncertainty. The results were compared in terms of cost, reliability, renewable energy penetration, renewable energy curtailment, and changes in battery cost. The optimization results showed that the string inverter is best in terms of cost and highly affected by the decrease of the battery cost, the AC module in terms of reliability and curtailment, and the multi-string for renewable energy penetration. Meanwhile, the central inverter can be the choice when a balance between cost and reliability is considered.