AixLib.Electrical.Interfaces.Load

# .AixLib.Electrical.Interfaces.Load

Partial model for a generic load

## Information

This model represents a generic load that can be extended to represent either a DC or an AC load.

The model has a single generalized electric terminal of type AixLib.Electrical.Interfaces.Terminal that can be redeclared. The generalized load is modeled as an impedance whose value can change. The value of the impedance can change depending on the value of the parameter `mode`, which is of type AixLib.Electrical.Types.Load:

Mode | Description | Explanation
--- | --- | ---
AixLib.Electrical.Types.Load.FixedZ_steady_state | fixed Z steady state | The load consumes exactly the power specified by the parameter `P_nominal`.
AixLib.Electrical.Types.Load.FixedZ_dynamic | fixed Z dynamic | The load consumes exactly the power specified by the parameter `P_nominal` at steady state. Depending on the type of load (e.g., inductive or capacitive) different dynamics are represented.
AixLib.Electrical.Types.Load.VariableZ_P_input | variable Z P input | The load consumes exactly the power specified by the input variable `Pow`.
AixLib.Electrical.Types.Load.VariableZ_y_input | variable Z y input | The load consumes exactly the a fraction of the nominal power `P_nominal` specified by the input variable `y`.

#### Conventions

It is assumed that the power `P` of the load is positive when produced (e.g., the load acts like a source) and negative when consumed (e.g., the source acts like a utilizer).

#### Linearized models

The model has a Boolean parameter `linearized` that by default is equal to `false`. When the power consumption of the load is imposed, this introduces a nonlinear equation between the voltage and the current of the load. This flag is used to select between a linearized version of the equations or the original nonlinear ones.
When the linearized version of the model is used, the parameter `V_nominal` has to be specified. The nominal voltage is needed to linearize the nonlinear equations.

Note: A linearized model will not consume the nominal power if the voltage at the terminal differs from the nominal voltage.

## Contents

Name | Description
--- | ---
PhaseSystem | Phase system

## Revisions

- January 30, 2019, by Michael Wetter:
  Set start value for `P`.
- November 28, 2016, by Michael Wetter:
  Removed zero start value for current. The current is typically non-zero and zero is anyway the default start value, hence there is no need to set it.
  This is for #584.
- September 17, 2016, by Michael Wetter:
  Corrected wrong annotation to avoid an error in the pedantic model check in Dymola 2017 FD01 beta2.
  This is for issue 557.
- February 26, 2016, by Michael Wetter:
  Set default value for `P_nominal` and removed assertion warning. This is required for pedantic model check in Dymola. This is for #426.
- September 24, 2015 by Michael Wetter:
  Provided value for `P_nominal` if `mode <> AixLib.Electrical.Types.Load.VariableZ_P_input`. This avoids a warning during translation of AixLib.Examples.ChillerPlant.DataCenterRenewables.
- September 4, 2014, by Michael Wetter:
  Changed the parameter from `linear` to `linearized` because `AixLib.Fluid` also uses `linearized`. This change has been done to use a consistent naming across the library.
- June 17, 2014, by Marco Bonvini:
  Adde parameter `initMode` that can be used to select the assumption to be used during initialization phase by the homotopy operator.
- May 15, 2014, by Marco Bonvini:
  Created documentation and revised model.
- October 31, 2013, by Marco Bonvini:
  Model included in the Buildings library.

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