Datasheet

In the block scheme the mechanic part is included, where “p” is the number of pole pairs, while “B” represents friction,
“J” the inertia, “
load
“ the load torque and “” the motor torque:
 p
2
3

The angular speed  is represented in the scheme as 
e
to distinguish the electrical speed from the mechanical one.
Let’s now consider the equations we have seen in (,) system:
dt
d
iRv
dt
d
iRv
S
S








These equations show that magnetic flux can be obtained from applied voltages and measured currents simply by
integration:
diRv
dtiRv
S
t
S
t
)(
)(
0
0
0
0








Furthermore:




Li
Li
m
m


)sin(
)cos(
If the synchronous inductance L is small, the current terms can be neglected, if not they have to be considered. In
general:




LidtiRvLiy
LidtiRvLix
S
t
m
S
t
m




)()sin(
)()cos(
0
0
0
0
So in the (,) system phase we obtain from the flux components:
)arctan(
y
x
 
The system speed  can be obtained as the derivative of the angle.
)(t
dt
d
 
Based on this, a sensor-less control algorithm was developed to give the imposed phase voltages, to measure phase
currents, to estimate the angular position  and finally the system speed.