The system is first investigated through computer simulation.
The salient parameters of the drive are given in the
Appendix. Fig. 13(a) shows the simulated drive characteristics
upon step change in command speed. As can be seen
from this figure, a first-order speed response is realized as a
consequence of sliding line S3 (19) being implemented. Fig.
13(b) shows the effect of plant parameter variation (drive inertia
doubled) on drive control performance. Inspection of
this figure indicates no significant change in speed response
as compared with Fig. 13(a). Parameter-insensitive characteristics
are exemplified. As a consequence of the inner-loop
decoupling controller, no deviation in flux level is observed
in these results. Withermore, the steady-state speed error is
almost zero. The validity of the simulations is confirmed by
experimental results, as is shown in the oscillographs in Fig.
14(a) and (b). The drive inertia is doubled in Fig. 14(b). The
speed response is almost identical in both Fig. 14(a) and (b).
There is a fair agreement between simulated and experimental
results. The control responses of speed reversal are illustrated
in Fig. 14(c). Due to sliding line S3, the speed follows a first