Development of Resonant Auxiliary Power Supply Unit Resonant Destruction Failure Detection and Harmonic Reduction Control Algorithm for Railway Vehicle

In this paper, a method and control algorithm for detecting resonance failures in resonant auxiliary power supply for railway vehicles is proposed. To achieve lightweighting of auxiliary power supply, it is imperative to reduce the input voltage to enable high-speed switching, thereby reducing the weight and volume of winding materials. Therefore, this paper proposes a control algorithm for lightweighting resonant auxiliary power supply for railway vehicles by applying LLC resonant converters, simultaneously proposing a method for detecting resonant destruction failures caused by abnormalities in converter components. The proposed algorithm uses the input stage buck converter to reduce the LLC resonant converter input voltage for high-speed switching and then controls the inverter input voltage through the LLC resonant converter. The proposed topology utilizes input buck converters to reduce the input voltage for high-speed switching and subsequently controls the input voltage of the inverter through LLC resonant converters. In addition, this paper proposes an inverter control algorithm to reduce harmonic distortions (THD) in the output voltage. The proposed algorithm analyzes and formulates a method for detecting resonance current peaks based on load capacity for resonance failure detection while the harmonic reduction algorithm utilizes d-q transformation to extract and nullify 5th and 7th order harmonics in the voltage.