The interest on hardware-in-the-loop (HIL) simulators of power electronic circuits in the field of automotive, as well as in the field of energy supply, has increased in the last decades. While the interest of the automotive sector increases, due to the move from conventional to electric or hybrid electric vehicles, the power suppliers interests are based on the increasing complexity, which is the result of the decentralization structure of the grid and the involvement of renewable energy sources, like wind or solar energy. This thesis investigates in modeling approaches for power electronic circuits. The focus is on the analysis and advancement of known approaches, which are rated by their computation effort, memory usage, algorithmizability, generalizability and usability on processor- and especially Field-Programmable-Gate-Array-based real-time systems. Furthermore, an automatic generation procedure for supporting the engineer by creating an application specific and real-time capable oversampling model for HIL-simulation is presented. At the end of this thesis, based on two chosen modeling approaches, a HIL-simulation of a rectifier with power factor correction is described. Measurements on the real plant and the HILsimulator are compared and serve as proof of applicability. The interest on hardware-in-the-loop (HIL) simulators of power electronic circuits in the field of automotive, as well as in the field of energy supply, has increased in the last decades. While the interest of the automotive sector increases, due to the move from conventional to electric or hybrid electric vehicles, the power suppliers interests are based on the increasing complexity, which is the result of the decentralization structure of the grid and the involvement of renewable energy sources, like wind or solar energy. This thesis investigates in modeling approaches for power electronic circuits. The focus is on the analysis and advancement of known approaches, which are rated by their computation effort, memory usage, algorithmizability, generalizability and usability on processor- and especially Field-Programmable-Gate-Array-based real-time systems. Furthermore, an automatic generation procedure for supporting the engineer by creating an application specific and real-time capable oversampling model for HIL-simulation is presented. At the end of this thesis, based on two chosen modeling approaches, a HIL-simulation of a rectifier with power factor correction is described. Measurements on the real plant and the HILsimulator are compared and serve as proof of applicability.