Simulation has played an important role in reducing design time and improving the reliability of power electronics systems. Over the years power electronics system diversity and complexity has grown to include subsystems which traditionally have used different modeling and simulation strategies, making the simulation of such systems difficult. This paper presents a standard simulation methodology for such complex power electronics systems based on cosimulation. This approach allows individual subsystems to be conveniently modeled in the most natural and trusted simulation environment. A simulation example of a four-phase buck converter employing digital control is provided. The power stage is modeled in Saber, and the digital controller is modeled in Simulink using the Xilinx System Generator blockset. The Saber-Simulink cosimulation is used as the interface between the two engines. Xilinx System Generator is used to automatically generate synthesizable code for Xilinx FPGAs.