Hey guys,
I’m working on a university Integrated Design Project and I’ve built a Simscape model on Matlab for the energy subsystem. I’m not asking anyone to do the work for me — I just want a sanity check on whether my modelling approach is technically reasonable before I write it up.
The system I’m trying to model is:
- 800 V DC bus
- Approx. 600 kW design load
- Renewable generation using:
- OTEC equivalent source
- PV solar branch
- Lithium battery storage
- DC-DC conversion into the main DC bus
- Closed-loop voltage control to keep the bus near 800 V
- Load disturbance / step change to test stability
- Efficiency calculated using ( Pout/Pin )
My current model uses average-value converter blocks rather than fully switching MOSFET-level converters, because the goal is more system-level behaviour than detailed semiconductor switching. I’ve also included sensors for bus voltage, current, load power, source power, and efficiency.
The main things I’d really appreciate help checking are:
- Is it reasonable to represent OTEC as a controlled DC/current source with internal resistance for this kind of assignment?
- Is using average-value DC-DC converter blocks acceptable for a high-level Simscape energy model?
- Does an 800 V bus and ~600 kW load imply a load resistance of about [R = \frac{800^2}{600000} \approx 1.07\Omega] and is this a sensible way to model the full load?
- Is closed-loop PI/PID voltage control on the converter duty cycle the right modelling approach?
- What outputs/plots would you expect to see to prove the model is working properly?
- Are there any obvious Simscape modelling mistakes I should watch for, such as grounding/reference issues, solver settings, or unrealistic source/load assumptions?
I’m aiming for a model that is defensible in a report, not necessarily an industry-grade converter design. Any advice on whether this architecture is sensible, or what would make the simulation more credible, would be really appreciated.
Thanks!