Theory of operation, design procedure and simulation of a bidirectional LLC resonant converter for vehicular applications

Usually a LLC resonant converter is used in applications with high input voltage (300-400 V) and low output voltage (48-60 V). This type of converter includes a half bridge topology and is only designed for unidirectional power transfer. Since the benefits of a LLC resonant converter are high efficiency, high power density and low EMI, it is a very interesting topology for vehicular applications. For bidirectional power transfer, a full bridge topology is established. In this way bidirectional functionality can be combined with high performance. In the past LLC resonant converters have been supplying telecommunication or consumer electronic - usually as a buck converter. In the present paper the challenge is to make it fit for automotive requirements.