Abstract: In this study, deals with the design, analysis and control of a multi input, DC/DC converter for the powertrain of a hybrid electric vehicle. The objective is to develop an integral solution of DC/DC converter and control that supports bidirectional operation in order to recover energy during regenerative braking. The presented DC/DC converter topology is a bidirectional buck-boost converter. The stability of this topology is analyzed considering the hybrid electric vehicle application. PI control is the chosen control method for the voltage loop of the bidirectional buck-boost converter due to its robustness and disturbances rejection capability. Then, the voltage PI control is designed by means of the small-signal transfer functions of the multi-input buck-boost converter.