Two FMU models are running in Simulink—how to resolve the algebraic loop problem?

I built a buck converter circuit with closed-loop control, and I wanted to test the export and import of Simulink FMU models. So I packaged the control module as a controlFMU and the circuit module as a buckFMU, then imported them back into Simulink and ran them as FMUs. However, the simulation reported an algebraic loop error. I then added delay blocks between the two FMU models, but the results were incorrect and the simulation ran very slowly. How can I solve this?

[Yifeng Tang]

Could you please describe the nature of the control & the plant? Discrete or continuous? Pure Simulink or some Simscape? What solver are you trying to use or left default?