Robust and ultrafast response compensator for unstable invertible plants

Quasi-linear feedback theory (Kelemen, 2002; Kelemen and Bensoussan, 2004) enabled simultaneously improving time performance and frequency performance of feedback systems, by using compensators whose poles are gain dependent. Although simulation results show theoretical improvements, the gain magnitude of quasi-linear compensators is prohibitive. This paper intends to present a different quasi-linear controller (Bensoussan, 2011) that achieves simultaneous time and frequency optimization: The design is based on gain considerations in order to propose a framework within which phase circuits can be used in order to affect essentially the time response. A practical design methodology is outlined.