Refactor `alt_eff` to be a FuelConverter/ReversibleEnergyStorage level aux load efficiency penalty

[kylecarow]

Necessary for #270 Not necessary, but useful

Auxiliary Load Efficiency Refactoring Architecture

Problem with current state

• In BEV, HEV, PHEV:

  • We do not account for electrical-electrical conversion (DC:DC) losses from the RES to aux power

• In HEV:

  • We do not account for mechanical-electrical conversion (alternator) losses from the FC to aux power
    • FuelConverter has alt_eff that accounts for this

• For FCEVs (modeled as a powertrain type around HybridElectricVehicle): there should be no alternator, so how should this be accounted for?

• Potential solutions, but not ideal:

  • Add alt_eff to HybridElectricVehicle (as in Alternator efficiency for HEVs (applies fc aux load only) #272)
    • Does not apply when we get to modeling FCEVs, FCEVs have no alternator
  • Introduce a single vehicle-level field
    • can't distinguish between mechanical (FC) vs electrical (RES) conversion losses
  • Introduce multiple vehicle-level fields, for FC and RES
    • possibility of modeling inapplicable vehicles (conventional vehicle with a RES aux load efficiency?)

Solution: Component-Level Efficiency Fields

Add optional aux_load_eff: Option<si::Ratio> to:

• FuelConverter — represents mechanical-to-electrical conversion (alternator for ICE, inapplicable for fuel cell)
• ReversibleEnergyStorage — represents electrical-to-electrical conversion (DC-DC inverter)

Add initialization checks

• Conv init:

  • FC: (0, 100%] range check on aux_load_eff

• HEV/PHEV init:

  • FC: (0, 100%] range check on aux_load_eff
  • RES: (0, 100%] range check on aux_load_eff

• FCEV init:

  • FC: ensure!(fc.aux_load_eff == None or Some(1.0))
  • RES: (0, 100%] range check
    -FC does not supply aux load directly for FCEVs, it comes from the RES

• create new optional field in FC and RES components for aux load efficiency penalty

  • FC: represents an alternator (fuel cell stacks dont directly supply aux power, all goes to RES)
    • for FCEV, check on initialization this value is None or Some(1.0), e.g.:

impl Init for FuelCellElectricVehicle {
    fn init(&mut self) -> Result<(), Error> {
        // Validate that FC doesn't have alternator (FCEV is purely electrical)
        if let Some(eff) = self.fc.aux_load_eff {
            ensure!(
                eff == 1.0 * uc::R,
                "FCEV fuel converter should not have alternator losses. aux_load_eff must be None or 1.0, got {}",
                eff.get::<si::ratio>()
            );
        }
        
        // ... rest of init
        self.fc.init()?;
        self.res.init()?;
        // ...
        Ok(())
    }
}

• RES: represents DC:DC conversion efficiency
• figure out how to maintain serde format compatibilty

Eventually port to style of #279, delegate some efficiency range checks to that implementation Did this already, why not