Comments on "Stability analysis, design, and simulation of a closed-loop converter-controlled DC drive" by P.B. Anjaneyulu, et al

Applying Popov's stability criterion to the correct transfer function for the system studied in the work P.B. Anjaneyulu et al. (see ibid., vol.IE-31, no.2, p.175-80, (1984)), suitable conditions for stability are derived. From these conditions, the stability region obtained is larger than that given in the mentioned work. These results can be verified by using Lyapunov's second method.<
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