Design Optimization of a 1500 V GaN-Based Solar Inverter Using Flying Capacitor Multi-Level Converter Stages

Utility scale solar installations are adopting 1500 V solar inverters with reduced cabling and installation costs. Flying capacitor multi-level (FCML) inverters with 650 V transistors offer unique system benefits, leading to lower volume and weight reductions while improving upon system efficiency. Here, we present the design optimization of FCML inverters for 1500 V with considerations of different switches, number of levels, switching frequency and passive components. The optimization informed the design of a 5-level FCML with 650 V GaN switches which was demonstrated successfully in hardware.