Subsystems

• A subsystem has 1 or more Port
• Each port has 2 variables (generally referred to as the Effort, $e(t)$, and the Flow, $f(t)$)
  • For the figure above we have the following relations.
  • $(\tau ,\omega ),(F,v)$
  • $(\Delta P,Q),(F,v)$
  • $(u_a,i_a),(u_f,i_f),(\tau ,\omega )$
• Energy can flow through ports or Power Ports
• The variables of Power Ports are called Power Variables because their product is power.
  • $P(t)=e(t)f(t)$

Observation We can connect the diagrams where they are able to exchange energy, which is why we use the names power parts and Power Bonds.