A study of critical information (maximum current and voltage estimation for the used components, mean values for semiconductor parts and an assessment of expected power losses) for a half-bridge bidirectional buck boost DC-DC converter equipped with an LC filter is carried out. A practical model from this converter is derived and a transfer function from the duty cycle and from the voltages (input to the output) is calculated via a linearization method. A signal flow graph of the converter can be obtained. To decrease the power losses, the concept of zero voltage switching is used and explained.