Modularer kaskadierter H-Brücken-Multilevel-Wechselrichter auf PV-MPPT-Basis

Inverters are classified based on the configuration of the PV system, the configuration of the conversion stages within the inverter, and whether they use transformers. After an introduction to the state of the art in inverters for PV systems with and without transformers, the focus of the contribution is on some known issues and challenges associated with transformerless inverters. Transformerless topologies offer significant advantages such as reduced weight, volume, and cost. The elimination of leakage current is one of the main issues for transformerless inverters in grid-connected photovoltaic systems, with the technical challenge being to maintain the common-mode voltage of the system constant in order to reduce leakage current. To achieve better utilization of the PV modules and maximize solar energy harvesting, a distributed maximum power point tracking control scheme is applied to both single-phase and three-phase multilevel inverters, allowing for independent control of each DC intermediate voltage.