
21-16 Power Electronics and Motor Drives
change of the rotor time constant, T
r
, results in deviation in the slip frequency value,
sl
, calculated from
Equation 21.39. e predicted rotor ux position, γ
src
= ∫(p
b
m
+
slc
)dt, deviates from the actual position
angle, γ
sr
= ∫(p
b
m
+
r
)dt, which produces a torque angle (see Figure 21.2) deviation, δ = γ
src
− γ
sr
, and,
consequently, leads to an incorrect subdivision of the stator current vector, I
s
, into two components, I
sd
and I
sq
. e decoupling condition of ux and torque control cannot be achieved. is leads to
• Incorrect rotor ux, Ψ
r
, and torque current component, I
sq
, values in the steady-st ...