Power electronic devices are growing in importance in automotive applications. Power converters are used in hybrid electric vehicles but also in other vehicle applications like electric steering systems. For testing electronic equipment hardware-in-the-loop simulation is a today's standard method in the automotive industry. This always requires a real-time simulation of the plant. For testing the electronic control units of power electronics, real-time capable models of power electronic circuits need to be developed, accordingly. This paper presents an approach for the real-time simulation of power electronic circuits which is an enhanced formulation of the discrete Space-Averaging-Method but considers practical aspects for real-time simulation like the computation time. The approach is proven by simulation results.