PLECS 3.4 Online Help

DC Machine

Purpose

Simple model of DC machine

Library

Electrical / Machines

Description

pict

The machine operates as a motor or generator; if the mechanical torque has the same sign as the rotational speed the machine is operating in motor mode, otherwise in generator mode. In the component icon, the positive poles of armature and field winding are marked with dots.

Electrical System

pict

Electromagnetic torque:

Te = Laf ⋅if ⋅ia

Induced voltage of the armature winding:

Ea = Laf ⋅if ⋅ωm

Mechanical System

       1
ωm  =  -(Te - F ωm - Tm)
       J

Parameters

Armature resistance
Armature winding resistance Ra   in ohms (_O_  ).
Armature inductance
Armature winding inductance La   in henries (H).
Field resistance
Field winding resistance Rf   in ohms (_O_  ).
Armature inductance
Field winding inductance Lf   in henries (H).
Field-armature mutual inductance
Field-armature mutual inductance Laf    in henries (H).
Inertia
Combined rotor and load inertia J   in Nms2  .
Friction coefficient
Viscous friction F   in Nms.
Initial rotor speed
Initial mechanical speed ωm,0   in radians per second (- 1
s  ).
Initial rotor position
Initial mechanical rotor angle θm,0   in radians.
Initial armature current
Initial current ia,0   in the armature winding in amperes (A).
Initial field current
Initial current if,0   in the field winding in amperes (A).

Probe Signals

Armature current
The current ia   in the armature winding, in amperes (A).
Field current
The current if   in the field winding, in amperes (A).
Rotational speed
The rotational speed ωm   of the rotor in radians per second (s-1  ).
Rotor position
The mechanical rotor angle θm   in radians.
Electrical torque
The electrical torque Te   of the machine in Nm.