Multi-tank resonant topologies as key design factors for reliability improvement of power converter for power energy applications

To improve electrical properties of power converters suited for power energy systems, the paper deals with investigation of novel multi-tank resonant topologies. First, standard LLC converter is analyzed, as well as mathematical model during operation intervals is developed. After it, modifications of LLC converter for better dynamic behavior during start-up and short-circuit operation are described, whereby both operation modes have been verified and compared with standard solution. Next, modifications of LLC converter for electric drive applications were made. The main criterion was achievement of low value of THD of output variables (voltage and current). Based on analysis, physical model was constructed, whereby key results are experimentally supported at the end of the paper. Each design is confirmed with precise measurements. Each modification of standard LLC converter is mathematically supported to understand basic design of multi-tank resonant converters for modern industrial applications.