Buildings.Electrical.DC.Storage

This package contains models that represent different energy storages for DC power.

Package Content

Name	Description
Battery	Simple model of a battery
Examples	Package with example models
BaseClasses	Base models for battery package

Buildings.Electrical.DC.Storage.Battery

Information

This model takes as an input the power that should be stored in the battery (if P > 0) or that should be extracted from the battery. The model uses a fictitious conductance (see Buildings.Electrical.DC.Loads.Conductor) G such that P = u i and i = u G, where u is the voltage difference across the pins and i is the current at the positive pin.

The output connector SOC is the state of charge of the battery. This model does not enforce that the state of charge is between zero and one. However, each time the state of charge crosses zero or one, a warning will be written to the simulation log file. The model also does not limit the current through the battery. The user should provide a control so that only a reasonable amount of power is exchanged, and that the state of charge remains between zero and one.

Parameters

Connectors

Modelica definition

Type	Name	Default	Description
Real	etaCha	0.9	Efficiency during charging [1]
Real	etaDis	0.9	Efficiency during discharging [1]
Real	SOC_start	0.1	Initial state of charge [1]
Energy	EMax		Maximum available charge [J]
Voltage	V_nominal		Nominal voltage (V_nominal >= 0) [V]

Type	Name	Description
input RealInput	P	Power stored in battery (if positive), or extracted from battery (if negative) [W]
output RealOutput	SOC	State of charge [1]
Terminal_p	terminal	Generalized terminal

model Battery "Simple model of a battery" parameter Real etaCha(min=0, max=1, unit="1") = 0.9 "Efficiency during charging"; parameter Real etaDis(min=0, max=1, unit="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"; parameter Modelica.SIunits.Voltage V_nominal "Nominal voltage (V_nominal >= 0)"; Modelica.Blocks.Interfaces.RealInput P(unit="W") "Power stored in battery (if positive), or extracted from battery (if negative)"; Modelica.Blocks.Interfaces.RealOutput SOC(min=0, max=1, unit="1") "State of charge"; Buildings.Electrical.DC.Interfaces.Terminal_p terminal "Generalized terminal"; protected Buildings.Electrical.DC.Storage.BaseClasses.Charge cha( final EMax=EMax, final SOC_start=SOC_start, final etaCha=etaCha, final etaDis=etaDis) "Charge model"; Loads.Conductor bat( final P_nominal=0, final mode=Buildings.Electrical.Types.Load.VariableZ_P_input, final V_nominal=V_nominal) "Power exchanged with battery pack"; Modelica.Blocks.Math.Gain gain(final k=-1); equation connect(cha.SOC, SOC); connect(cha.P, P); connect(bat.terminal, terminal); connect(P, gain.u); connect(gain.y, bat.Pow); end Battery;