3-Periodic Compensation of Discrete-Time Plants

The fact that the periodic controllers, by virtue of their loop-zero placement capability, provide better robustness as compared to the Linear Discrete Time-Invariant (LDTI) ones while compensating an unstable, LDTI, Non-Minimum Phase (NMP) plant is well explicated in the literature. In this paper an algorithm, that involve solution of linear algebraic equations, for the synthesis of a 3-periodic controller has been proposed. Finally, an illustrative example is presented to compare the performance of such controller with LDTI and 2-periodic controllers.