robert 702647d84e Updated the parameter names contained within the matlab controller david1606

TBD: parameters outside the controller, parameters contained on the old parameter doc

2026-09-11 13:05:38 +00:00

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SHIFT Simulator — Input/Output Interface

Markdown report of a non-markdown source document.

Source docs/_originals/Simulator Interface Input-Output sheet.pdf

Format PDF, 10 pages, 556 kB

MD5 0712f05593c39897abc8f651834bebde

Owner AI & Control Systems cluster

Document status Draft v0.1 — living document, TBD items unresolved

Report generated 2026-07-25


Source	`docs/_originals/Simulator Interface Input-Output sheet.pdf`
Format	PDF, 10 pages, 556 kB
MD5	`0712f05593c39897abc8f651834bebde`
Owner	AI & Control Systems cluster
Document status	Draft v0.1 — living document, TBD items unresolved
Report generated	2026-07-25

Note

Tables in the source PDF are rendered in a layout that machine extraction scrambles (symbol, name, unit and note columns interleave). The tables below are reconstructed — the content is the source's, the column alignment is this report's. Where a mapping was ambiguous it is flagged inline. Check against the original PDF before relying on any single row for implementation.

Purpose

Defines the contract between the SHIFT microgrid simulator and everything that talks to it:

the AI/RL policy,
the rule-based baseline,
the validation/benchmark layer,
the Economics team's downstream cost and CO₂ accounting.

It covers what the simulator consumes (configuration, exogenous time-series, control actions) and what it returns at every timestep.

"It is a living document — items flagged TBD need a decision from the cluster or whoever."

This document is the direct descendant of Shift Input Data — §1 explicitly refers to "the constants Robert's doc lists in bold."

0. Conventions

Timestep

Symbol: dt

Default assumption 1 hour — matches typical PV/load profiles and the one-year benchmarking horizon in the project brief. Whether a sub-hourly step is needed for battery fast-response behaviour is TBD.

"I did 1 hour for this cause 15 mins time steps will be quite compute heavy for RL training, so we do need to talk about that."

Sign conventions

Quantity	Positive means	Negative means
`P_battery`	discharging (supplying the bus)	charging (absorbing from the bus)
`P_grid`	importing from grid	exporting to grid
`n_H2_net`	net production into tank	net consumption from tank

All other power values — P_PV, P_electrolyser, P_fuelcell, P_load — are non-negative by definition.

Power balance

The invariant the simulator must satisfy at every step:

P_PV_used + P_fuelcell + P_grid + P_battery
      = P_load_served_critical + P_load_served_noncritical + P_electrolyser

Any residual after the policy's action is absorbed by unmet load — with critical load prioritised (see §4).

Units

SI throughout: power in W, energy in Wh, mass in kg, amount in mol, time in s (or h for hourly steps). TBD to lock down before code is written.

"I don't know the conventions for this, I let AI handle this, not an electrical engineer sorry."

1. Static configuration inputs

Set once per simulation run.

1.1 Electrolyser

Symbol	Name	Unit	Notes
`N_c_ele`	Number of cells	—	Usually difficult to find
`mu_F`	Faraday efficiency	—	Fall back to literature average (~0.95–0.99 for PEM)
`P_Electro_max`	Rated / max power	W
`P_ele_min`	Minimum operating power	W	Below this the electrolyser shuts off (efficiency cliff)
`I_ele_min`	Minimum operating current	A	Alternative to `P_ele_min`
`cal_H2`	H₂ production calibration factor	—	If we end up reading H₂ flow from measured data

1.2 Fuel cell

Symbol	Name	Unit	Notes
`N_c_fc`	Number of cells	—
`utilisation_fc`	H₂ utilisation	%
`P_FuelCell_max`	Maximum output power	W	Project spec: 100 kW
`V_fc_min`, `V_fc_max`	Operating voltage range	V

1.3 Hydrogen tank

Symbol	Name	Unit	Notes
`E_H2_max`	Maximum electrical energy capacity of the storage tank	J
`V_H2_max`	Maximum stored volume	L (or kg)	Project spec: up to 200 kg total across two tanks
`V_H2_init`	Initial fill level	L (or kg)
`T_tank`	Operating temperature	K	TBD — isothermal assumption likely fine
`p_tank`	Operating pressure	atm (or bar)	TBD — isobaric vs. ideal-gas model

1.4 PV

Symbol	Name	Unit	Notes
`A_PV`	Total panel area	m²	Project spec: 2,300 m²
`mu_PV`	Panel efficiency	—
`P_PV_max`	Inverter / rated cap	W	Optional; if set, clipping occurs above this

1.5 Battery

Symbol	Name	Unit	Notes
`E_rated`	Rated energy capacity	Wh
`E_battery_max`	Maximum energy capacity	Wh
`Q_rated`	Rated charge capacity	Ah
`P_battery_max`	Max (dis)charge power (assuming both are identical - this is the current assumption in the Simulink Controller)	W
`P_battery_charge_max`	Max charge power	W
`P_battery_discharge_max`	Max discharge power	W
`SoC_init`	Initial state of charge	— (0–1)
`SoC_min`, `SoC_max`	Operating window	— (0–1)	E.g. 0.1–0.9
`eta_batt_ch`, `eta_batt_dis`	Round-trip efficiencies	—	Often split into charge & discharge

1.6 Load

Symbol	Name	Unit	Notes
`V_load`	Bus voltage	V	Constant, per Robert's note

1.7 Grid

Symbol	Name	Unit	Notes
`P_grid_max`	Max connection capacity (import & export)	W	Constant, per Robert's note
`V_grid`	Bus voltage	V

2. Per-timestep inputs

2.1 Exogenous time-series

Read from data; not under policy control.

Symbol	Name	Unit	Source / note
`G(t)`	PV generated power	W	Forecasted
`L_crit(t)`	Critical hospital load demand	W	ICU, life-support, etc. — must always be served
`L_noncrit(t)`	Non-critical hospital load demand	W	Lighting, HVAC, admin
`grid_on(t)`	Grid availability (1/0)	—	Models outages
`price(t)`	Grid electricity price	€/kWh	Import & export prices — TBD whether they differ
`CO2_int(t)`	Grid carbon intensity	kg CO₂/kWh	For emissions accounting

2.2 Control inputs

From the AI/RL policy or the rule-based baseline. At each timestep the controller emits setpoints, not direct power flows — the simulator clips them to physical limits and reports actuals.

Symbol	Name	Unit	Range
`u_ele(t)`	Electrolyser power setpoint	W	`[0, P_ele_max]`; values in `(0, P_ele_min)` round to 0 (off)
`u_fc(t)`	Fuel cell power setpoint	W	`[0, P_fc_max]`
`u_batt(t)`	Battery setpoint (signed)	W	`[-P_batt_charge_max, P_batt_discharge_max]`
`sw_ele(t)`	Electrolyser ON/OFF	1/0	Optional — can be folded into `u_ele = 0`
`sw_fc(t)`	Fuel cell ON/OFF	1/0	Optional — can be folded into `u_fc = 0`

On the grid: the grid is treated as the slack bus — whatever the power-balance residual is after all other components act, the grid absorbs, within P_grid_max and grid_on(t). The RL action space therefore probably does not include the grid directly.

3. Per-timestep outputs

3.1 State variables

Carried forward to the next step.

Symbol	Name	Unit
`SoC(t)`	Battery state of charge	— (0–1)
`E_battery_SOC(t)`	Energy currently present in battery	J
`E_H2_SOC(t)`	Electrical Energy that can be currently extracted from the Hydrogen Storage Tank	J
`H2_level(t)`	H₂ stored in tank	mol (or kg)
`T_tank(t)`	Tank temperature	K (only if non-isothermal model)
`p_tank(t)`	Tank pressure	bar (if modelled)

3.2 Power flows

Symbol	Name	Unit
`P_PV(t)`	PV power available given irradiance	W
`P_PV_used(t)`	PV power actually consumed	W
`P_PV_curtailed(t)`	PV potential that was thrown away	W
`P_ele(t)`	Actual electrolyser consumption	W
`P_fc(t)`	Actual fuel cell output	W
`P_batt(t)`	Actual battery flow (signed)	W
`P_grid(t)`	Actual grid flow (signed)	W
`P_load_served_crit(t)`	Critical load served	W
`P_load_served_noncrit(t)`	Non-critical load served	W
`P_load_P(t)`	Power to be covered after PV (+ve = remaining power shortage, -ve = surplus to be used)	W
`P_load_PB(t)`	Power to be covered after PV and Battery (same convention as P_load_P)	W
`P_load_PBH(t)`	Power to be covered after PV, Battery and Hydrogen stroage tank (same convention as P_load_P(B))	W
`P_battery_cont(t)`	Power amount the controller determines the battery should (dis)charge at (accounting for battery properties and demand)	W
`P_FuelCell_cont(t)`	Power amount the controller determines the fuel cell should provide (accounting for it's properties and demand)	W
`P_Electro_cont(t)`	Power amount the controller determines the electrolyser should extract (accounting for it's properties and demand)	W

3.3 Mass flows (hydrogen)

Symbol	Name	Unit
`n_H2_prod(t)`	H₂ produced by electrolyser	mol/s (or kg/h)
`n_H2_cons(t)`	H₂ consumed by fuel cell	mol/s (or kg/h)
`n_H2_net(t)`	Net flow into tank	mol/s

3.4 KPIs and accounting

"the heart of the task"

Symbol	Name	Unit	Notes
`unmet_crit(t)`	Unserved critical load	W	Must be near-zero — primary resilience KPI
`unmet_noncrit(t)`	Unserved non-critical load	W	Restated as a KPI for clarity
`curtailment(t)`	`= P_PV_curtailed(t)`	W
`cost(t)`	Operating cost of this step	€	TBD — see §5
`CO2(t)`	Emissions of this step	kg CO₂	TBD — see §5

3.5 Diagnostic / efficiency outputs

Recommended. Ties directly to AI Efficiency Improvements, which flagged ~30–40% electrolyser losses and ~40% fuel-cell losses as the biggest optimisation targets. If the simulator returns per-step efficiencies, the RL reward and the post-hoc analysis can both attack those losses directly.

Symbol	Name	Unit
`eta_ele(t)`	Electrolyser efficiency this step	—
`eta_fc(t)`	Fuel cell efficiency this step	—
`eta_PV(t)`	Effective PV efficiency this step	—
`eta_batt(t)`	Battery round-trip-equivalent	—

4. Priority rules the simulator enforces

Not I/O, but contract-level — the policy needs to know what the simulator will do with a setpoint that violates physics or safety.

Critical load is sacred. If the policy's setpoints leave critical load unserved while the battery has charge, the fuel cell can run, or the grid is available, the simulator overrides the policy in that order and reports the override (e.g. via an output flag) so it shows up in training.
State limits are hard. SoC ∈ [SoC_min, SoC_max], H2_level ∈ [0, V_H2_max]. Setpoints that would breach these are clipped; the difference shows up as P_batt(t) vs u_batt(t).
Electrolyser dead-zone. Setpoints in (0, P_ele_min) are rounded to 0.
Grid outage. If grid_on(t) = 0 then P_grid(t) = 0 regardless of slack residual; the residual becomes unmet_* or curtailment.

5. Open questions

Need answers before v1.0.

Cost & CO₂ scope. Flagged TBD in §3.4. If Economics handles these downstream, the simulator only needs to return P_grid(t) plus exogenous price(t) and CO2_int(t), and Economics computes cost/CO₂ themselves. If the simulator computes them, it also needs to know whether there is an O&M cost per kWh through the electrolyser/fuel cell, a degradation cost, and so on.
Tank model. Isothermal + ideal gas, or do we need temperature and pressure dynamics?
Battery degradation. Modelled or ignored?
Sub-hourly dynamics. Does the battery's fast-response role require dt < 1 h? If so, mixed time-scale handling between battery (minutes) and electrolyser (hours) becomes a design question.
Action space format. Continuous setpoints (u_ele ∈ [0, P_ele_max]) vs. discrete buckets — affects what the RL team expects as input.
Forecast vs. realised exogenous inputs. The policy may see a forecast of G(t+1) and L(t+1); the simulator advances with the realised values. Decide whether the simulator delivers both or only realised.
Critical vs non-critical split — data availability. Confirm with the hospital data source whether the load profile can actually be split, or whether we need a proxy fraction (e.g. assume X% of total load is critical).
Mutual exclusion of electrolyser and fuel cell. Should the action space structurally prevent simultaneous operation (mode-switch / hybrid action space), or allow them independently and let the reward penalise simultaneous operation? Has efficiency, sample-efficiency, and policy-expressiveness trade-offs.

Cross-document notes

Three consistency issues between this document and its neighbours:

Issue	Detail
Naming convention	This document uses physics-style symbols (`P_PV`, `SoC(t)`, `u_ele`). RL State Variables and RL Action Variables use descriptive identifiers (`PV_Generation`, `Battery_SOC`, `Electrolyzer_PowerSetpoint`). Neither references the other; one must win.
State coverage	This sheet omits component temperatures, stack health, and water level, which the RL state doc lists. Consistent with the isothermal/no-degradation assumptions flagged TBD above.
Action coverage	This sheet accepts 5 control signals; the RL action doc lists 16. Grid import/export and load shedding are deliberately excluded here (slack bus, and outcome-not-action respectively); PV curtailment control, thermal management, and mode supervision are genuine gaps.

Load-tier terminology also differs from Energy Management's BIDMC/UCSD Energy Flow and Balances, which uses a three-tier model (Tier 1 critical / Tier 2 essential / Tier 3 non-critical) against this document's two-way split (L_crit / L_noncrit).

Shift Input Data — the predecessor variable list this sheet formalises
RL State Variables · RL Action Variables · RL Reward Function
Rule-Based Controller — the baseline policy that consumes this contract
Forecasting Requirements — produces G(t), L(t), price(t)

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