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Guilherme Keiel
Escola de Engenharia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre - RS
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Jeferson V. Flores
Escola de Engenharia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre - RS
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Luís Fernando A. Pereira
Escola de Engenharia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre - RS
Keywords:
Uninterruptible power supplies, multiple-resonant controller, droop control, decentralized control
Abstract
This paper presents a methodology for the design of multiple resonant controllers to the voltage regulation in uninterruptible power supplies (UPSs) operating in parallel. First, a state space representation of the interconnected system operating with decentralized controllers is obtained, based only on local measurements. Conditions are proposed in the form of linear matrix inequalities (LMIs) that guarantee the robust stability of the system given the insertion/removal of new sources or load variations. The synthesis of the controllers is based on the solution of a convex optimization problem directly related to the RMS value of the circulating current between the UPSs. Simulations considering the parallelism of two 3.5 kVA UPSs via droop control are presented to illustrate the proposed method.
