Buildings.Electrical.DC.Storage.BaseClasses

Name	Description
Charge	Model to compute the battery charge

This model two parameters η_CHA and η_DIS that represent the efficiency during the charge and discharge of the battery.

The model given the power P that should be provide or taken from the battery and compute the actual power flowing through the battery as

Equation	Condition
P_actual = P η_CHA	P ≥ 0
P_actual = P (2 - η_DIS)	P < 0

The actual power is then used to compute the variation of the state of charge SOC. The state of charge is the state variable of this model and is a real value between 0 and 1.

Note:The input power P has to be controlled in order to avoid the state of charge SOC exceeding the range between 0 and 1.

Parameters

Connectors

Modelica definition

Type	Name	Default	Description
Efficiency	etaCha	0.9	Efficiency during charging [1]
Efficiency	etaDis	0.9	Efficiency during discharging [1]
Real	SOC_start	0.1	Initial state of charge [1]
Energy	EMax		Maximum available charge [J]

Type	Name	Description
input RealInput	P	[W]
output RealOutput	SOC	State of charge

model Charge "Model to compute the battery charge" extends Modelica.Blocks.Icons.Block; parameter Modelica.SIunits.Efficiency etaCha(max=1) = 0.9 "Efficiency during charging"; parameter Modelica.SIunits.Efficiency etaDis(max=1) = 0.9 "Efficiency during discharging"; parameter Real SOC_start(min=0, max=1, unit="1")=0.1 "Initial state of charge"; parameter Modelica.SIunits.Energy EMax(min=0, displayUnit="kWh") "Maximum available charge"; Modelica.SIunits.Power PAct "Actual power"; Modelica.Blocks.Interfaces.RealInput P(final quantity="Power", final unit="W"); Modelica.Blocks.Interfaces.RealOutput SOC(min=0, max=1) "State of charge"; protected Boolean underCharged "Flag, true if battery is undercharged"; Boolean overCharged "Flag, true if battery is overcharged"; initial equation pre(underCharged) = SOC_start < 0; pre(overCharged) = SOC_start > 1; SOC = SOC_start; equation // Charge balance of battery PAct = if P > 0 then etaCha*P else (2-etaDis)*P; der(SOC)=PAct/EMax; // Equations to warn if state of charge exceeds 0 and 1 underCharged = SOC < 0; overCharged = SOC > 1; when change(underCharged) or change(overCharged) then assert(SOC >= 0, "Warning: Battery is below minimum charge.", level=AssertionLevel.warning); assert(SOC <= 1, "Warning: Battery is above maximum charge.", level=AssertionLevel.warning); end when; end Charge;