Feedback linearization control in photovoltaic module integrated converters

Leonardo Callegaro, Mihai Ciobotaru, Daniel J. Pagano, John E. Fletcher

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

The strive to increase the energy yield of photovoltaic (PV) power systems has made PV module integrated dc-dc converters (dc-MICs) a reality of modern PV plants. These converters regulate their input voltage, and their dynamic behavior is heavily influenced by the non-linear characteristic of the PV module. The regulation of the PV module voltage and average inductor current by means of a linear cascaded controller is a popular control technique, simplifying the converter dynamics, and providing inherent current limiting; however, it is prone to instability depending on the interaction between the PV source and the interfacing converter, as well as the value of the controller parameters. These factors present a clear challenge for control design; moreover, the converter transient response undesirably depends on the PV module operating point. In order to solve these issues, while maintaining regulation of PV module voltage and average inductor current, this paper proposes to adopt a non-linear controller designed with the feedback linearization control (FLC) technique. The control laws are derived and implemented in a non-inverting buck-boost dc module integrated converter, as this is a favorite topology for the PV interfacing application. A digitally controlled converter prototype is built and used to obtain experimental results, where the FLC technique is compared with a linear cascaded control technique. The results confirm the superior performance of the presented FLC technique, which is robust and able to regulate the converter input voltage with fast and consistent dynamics, regardless of the PV module or load operating conditions.

Original languageEnglish
Pages (from-to)6876-6889
Number of pages14
JournalIEEE Transactions on Power Electronics
Volume34
Issue number7
Early online date27 Sep 2018
DOIs
Publication statusPublished - Jul 2019

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