I have been tasked with creating a simulation model for a current controller connected to a three-phase inverter and a PMSM. The current controller is implemented with standard Simulink blocks. It should be discrete and operate at a frequency of 8 kHz. Thus a fixed step size of 1.25e-4 s is suitable for that part of the model. However, the model of the inverter and the PMSM should be continuous and modeled with Simscape components. Six N-Channel IGBT components should be used for the inverter and it is necessary to capture the dynamics of the transistors. Therefore, a small step size is necessary (maybe around 1e-8 s). Trying to simulate this, no matter the solver, typically results in either an error in the nonlinear solver (failed to converge) or the simulation running extremely slowly. I realize the slow simulation time might be a necessity to capture the fast dynamics, but i still wonder what the best way would be to configure the solver for this case? Would it help to separate the controller and the physical system into separate models and use the Model block in a third model to call them?