Replotting the Nyquist Plot - A New Visualization Proposal

In this paper, a new visualization of the Nyquist curve is proposed. Processing the open loop transfer function magnitude by the use of a nonlinear mapping proposed in this paper, the Nyquist plot is confined to a circle with the radius of two. The phase of the transfer function is not affected by the mapping. The mapping is monotonic, and it does not affect the topological statement of the Nyquist stability criterion. Also, magnitude of the transfer function equal to one is not affected by the proposed mapping, keeping the phase margin visualization. The method makes it simple to visualize stability properties of a closed loop system. Applications of control loop design in power electronic systems are emphasized. Examples are provided.