Loss Analysis of 3-level LLC Converter with Duty Control

In this paper, loss models of a Si IGBT system with a switching frequency of 10kHz and a SiC MOSFET system with a switching frequency of 100kHz are derived in a 3-level LLC converter with duty control, and the results are analyzed. Switching and conduction losses of power semiconductor devices are modeled, and losses are analyzed in the proposed circuit system. The loss model mathematically derived through analysis is compared and analyzed with the Psim simulation, and its validity is verified through similarity verification. In addition, it proves the possibility of miniaturization and weight reduction of the auxiliary power supply for railroad vehicles from the derived results.