.Spot.System

Information

The model System represents a global reference for the following purposes:

It allows the choice of

• nominal frequency (default 50 or 60 Hertz, but arbitrary positive choice allowed)
• system frequency or initial system frequency, depending on frequency type
• frequency type: parameter, signal, or average (machine-dependent) system frequency
• lower and upper limit-frequencies
• common phase angle for AC-systems
• synchronous or inertial reference frame for AC-3phase-systems
• transient or steady-state initialisation and simulation modes
  For 'transient' initialisation no specific initial equations are defined.
  This case allows also to use Dymola's steady-state initialisation, that is DIFFERENT from ours.
  Note: the parameter 'sim' only affects AC three-phase components.

It provides

• the system angular-frequency omega
  For frequency-type 'parameter' this is simply a parameter value.
  For frequency-type 'signal' it is a positive input signal.
  For frequency-type 'average' it is a weighted average over the relevant generator frequencies.
• the system angle theta by integration of

   der(theta) = omega 

  
  This angle allows the definition of a rotating electrical coordinate system
  for AC three-phase models.
  Root-nodes defining coordinate-orientation will choose a reference angle theta_ref (connector-variable theta[2]) according to the parameter ref:
  
  theta_ref = theta if ref = "synchron" (reference frame is synchronously rotating with theta).
  theta_ref = 0 if ref = "inertial" (inertial reference frame, not rotating).
  where
  theta = 1 : reference frame is synchronously rotating.
  ref=0 : reference frame is at rest.
  Note: Steady-state simulation is only possible for ref = "synchron".
  
  ref is determined by the parameter refFrame in the following way:

Note: Each model using System must use it with an inner declaration and instance name system in order that it can be accessed from all objects in the model.
When dragging the 'System' from the package browser into the diagram layer, declaration and instance name are automatically generated.

up users guide