The bond graph technique is applied to model a boost converter in order to derive an averaged model. The obtained averaged model is non-ideal as it takes into account most of the converter non-linearities introduced by power semiconductor devices. An ideal averaged model of the converter can be deduced easily for computing a non-linear control law in a real-time control context. The current-mode control of the boost converter is considered. The zero dynamics are studied by both classical theory and the bond graph approach. A modified version of a conventional nonlinear control law is proposed in order to improve the dynamic behaviour and to reduce the sensitivity to control model errors, The non-ideal averaged model is used firstly for simulation analyses of the proposed control law and then for comparison with experimental results.