A multi-input lead-lag power system stabilizer with H∞ control performance

In this paper we propose a design method of a low dimensional multi-input PSS which satisfies H-infinity performance. Although the H-infinity controller has a highly robust control performance, it has not been put into practical use because of the intricate of its theory and structure. Thus, to obtain high robustness, we deal with the H-infinity problem under the condition that the PSS structure is fixed as a lead-lag compensator. To this end, we add an additional reactive power input to the PSS. The parameter of the multi-input lead-lag PSS is optimized by Particle Swarm Optimization (PSO) that has an evaluation function which takes into account a closed loop H-infinity norm and a desired response. The damping of the PSS response is identified by using Prony method. The validity of the proposed PSS is demonstrated using a 3-machine 9-bus system model.