Buildings.Electrical.DC.Conversion

Package with models for DC/DC conversion

Information

This package contains models for DC/DC conversion. AC/DC converters can be found in the respective AC package.

Extends from Modelica.Icons.Package (Icon for standard packages).

Package Content

Name	Description
DCDCConverter	DC DC converter
Examples	Package with example models

Buildings.Electrical.DC.Conversion.DCDCConverter

DC DC converter

Buildings.Electrical.DC.Conversion.DCDCConverter

Information

This is a DC/DC converter, based on a power balance between the two DC sides. The parameter conversionFactor defines the ratio between the two averaged DC voltages. The loss of the converter is proportional to the power transmitted at the second DC side. The parameter eta is the efficiency of the transfer. The loss is computed as

P_loss = (1-η) P_DC,

where P_DC is the power transmitted. This model is symmetric and the power can be transmitted in both directions. The loss is computed depending on the direction of the power flow.

Extends from Buildings.Electrical.Interfaces.PartialConversion (Model representing a generic two port system for conversion).

Parameters

Type	Name	Default	Description
replaceable package PhaseSystem_p		PartialPhaseSystem	Phase system of terminal p
replaceable package PhaseSystem_n		PartialPhaseSystem	Phase system of terminal n
Voltage	VHigh		DC voltage on side 1 of the transformer (primary side) [V]
Voltage	VLow		DC voltage on side 2 of the transformer (secondary side) [V]
Efficiency	eta		Converter efficiency [1]
Ground
side 1
Boolean	ground_1	true	Connect side 1 of converter to ground
side 2
Boolean	ground_2	true	Connect side 2 of converter to ground

Connectors

Type	Name	Description
replaceable package PhaseSystem_p		Phase system of terminal p
replaceable package PhaseSystem_n		Phase system of terminal n

Modelica definition

model DCDCConverter "DC DC converter" extends Buildings.Electrical.Interfaces.PartialConversion( redeclare package PhaseSystem_p = PhaseSystems.TwoConductor, redeclare package PhaseSystem_n = PhaseSystems.TwoConductor, redeclare Interfaces.Terminal_n terminal_n, redeclare Interfaces.Terminal_p terminal_p); parameter Modelica.Units.SI.Voltage VHigh "DC voltage on side 1 of the transformer (primary side)"; parameter Modelica.Units.SI.Voltage VLow "DC voltage on side 2 of the transformer (secondary side)"; parameter Modelica.Units.SI.Efficiency eta(max=1) "Converter efficiency"; parameter Boolean ground_1 = true "Connect side 1 of converter to ground"; parameter Boolean ground_2 = true "Connect side 2 of converter to ground"; Modelica.Units.SI.Power LossPower "Loss power"; protected parameter Real conversionFactor = VLow/VHigh "Ratio of high versus low voltage"; Modelica.Units.SI.Current i1; Modelica.Units.SI.Current i2; Modelica.Units.SI.Voltage v1; Modelica.Units.SI.Voltage v2; Modelica.Units.SI.Power P_p "Power at terminal p"; Modelica.Units.SI.Power P_n "Power at terminal n"; equation Connections.potentialRoot(terminal_n.theta); Connections.potentialRoot(terminal_p.theta); if not ground_1 then i1 = 0; else v1 = 0; end if; if not ground_2 then i2 = 0; else v2 = 0; end if; P_p = PhaseSystem_p.activePower(terminal_p.v, terminal_p.i); P_n = PhaseSystem_n.activePower(terminal_n.v, terminal_n.i); v1 = terminal_n.v[2]; v2 = terminal_p.v[2]; sum(terminal_n.i) + i1 = 0; sum(terminal_p.i) + i2 = 0; // Voltage relation v_p = v_n*conversionFactor; // OLD equations that take into account the power at the secondary // power balance // LossPower = (1-eta) * abs(P_p); // P_n + P_p - LossPower = 0; // Symmetric and linear version LossPower = P_p + P_n; if i_n >=0 then i_p = i_n/conversionFactor/(eta - 2); else i_n = conversionFactor*i_p/(eta - 2); end if; end DCDCConverter;