Hello Tony,
you can use multiple power gui's if you split your model into seperate model references. This will enable for faster compiles, and if you take advantage of concurrent execution, can also speed up simulation: https://www.mathworks.com/help/simulink/ug/configure-your-model.html
The speed up is greater the closer in size the two SPS models are. If one is very small, and the other very large, you will see little speedup, but if both are large, you should see a speed increase. This approach is most often used when trying to meet real-time requirements. The models must only be connected by simulink wires in order to support connecting through a model reference. This will also require inserting filters or unit delays to break the loop. This decouples the model and slightly reduces the accuracy. If you split across an energy storage devices like dc-link capacitors, the system will decouple nicely in many cases. If you have to decouple across a part of the circuit that doesn't have some sort of filtering, the different in simulation accuracy will be more noticeable unless you reduce your step size.
Regards,
Joel
