Permanent-magnet motor model

1
Permanent-magnet motor model
ia
?,?

gt
ea
ea
?
?
ia
2
Electromechanical couplingF, force V, velocity
e, voltage i, current
B

e
V
F i x BL
...physics... .engineering.
e V x BL
F (BL)i
e (BL)V
3
PM Motor model schematic(Ref. Introduction
to System Dynamics, by Shearer, Murphy, and
Richardson, Figure 2-38.)
4
Harnessing e-m coupling in a motor(a denotes
the armature)
magnetic field, B
F BLia ea BLV ? RF V R?
R
V
B

?,?
F
armature windings
rotor
5
Typical circuit schematic
6
Ideal PM Motor model
Efficiency ?
7
PM Motor model with losses
Ra electrical resistance of the windings. Rm
mechanical friction.
ea ia
? ?
?i
eb
Ra
Rm
electrical . conversion . mechanical
8
PM Motor loss model equations
9
PM Motor model with dynamics
Electrical inductance and resistance of the
windings. Mechanical inertia of the rotor and
friction.
electrical conversion mechanical
10
PM Motor model with losses and dynamics equations
11
PM Motor model i/o equations
Inputs ea and ?L Outputs ia and ?
State equations
12
DC Motor model variable field
ef
if
If
1f
Rf
ea ia
? ?
ea ia
? ?
MGY
(B(if )LR)
if -controlled B-field