65
4)
Set the frequency of the three phase ideal source to match the frequency found in step
1.
5)
Adjust phase angle of the three phase ideal source so that the motor model starts at
the same point on wave that the measured data starts.
6)
Assign motor parameters an initial guess.
7)
Solve (4.1) (4.5) and (4.13) for the speed
r
, and the stator currents, i
as
, i
bs
, i
cs
.
8)
Compare the solution of step 7 to the measured data from step 3 and obtain a residual
error to express the error.
9)
Compare the residual error to the minimum allowable residual error. If the residual
error is greater than the minimum allowable residual error, proceed to step 10. If the
residual error is less than the minimum allowable residual error, terminate.
10) Update parameters and return to step 7.
Parameter Estimation
measured
simulated
Motor / Load
Model
x
lr
x
ls
x
m
r
r
r
s
i
as_simulated
i
bs_simulated
i
cs_simulated
i
as_measured
i
cs_measured
i
bs_measured
Ideal 3
460V Supply
Figure 42 Block diagram of the standard motor model parameter estimation process
4.3.5 Non-Linear Motor Model Parameters
In order to determine the value of the non-linear rotor terms, and the value of the modified
stator leakage reactance terms, a parameter estimation is used. Fig 43 shows the block
diagram of the parameter estimation process used to obtain these terms. For this parameter
estimation, the line impedance is also included in the model, but the line impedance terms are
not re-estimated. The parameter estimation process is similar to that of the standard motor
model parameter estimation process. The only exception is the addition of the terms D
xls
, C
rr
,
and C
xlr
and the line impedance model.