Open AccessDecentralised control of parallel inverters connected to microgrid using the derivative‐free non‐linear Kalman filter
Author(s) -
Rigatos Gerasimos,
Siano Pierluigi,
Zervos Nikolaos,
Cecati Carlo
Publication year - 2015
Publication title -
iet power electronics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.637
H-Index - 77
eISSN - 1755-4543
pISSN - 1755-4535
DOI - 10.1049/iet-pel.2014.0497
Subject(s) - control theory (sociology) , inverter , flatness (cosmology) , observer (physics) , nonlinear system , controller (irrigation) , kalman filter , extended kalman filter , microgrid , state observer , state variable , computer science , mathematics , grid , engineering , control (management) , physics , artificial intelligence , agronomy , geometry , thermodynamics , cosmology , quantum mechanics , voltage , electrical engineering , biology
Decentralised control for parallel inverters connected to the power grid is developed using differential flatness theory and the derivative‐free nonlinear Kalman filter. It is proven that the model of the inverters, is a differentially flat one. This means that all its state variables and the control inputs can be written as differential functions of a single algebraic variable which is the flat output. By exploiting differential flatness properties it is shown that the multiple inverters model can be transformed into a set of local inverter models which are decoupled and linearized. For each local inverter the design of a state feedback controller becomes possible. Such a controller processes measurements not only coming from the individual inverter but also coming from other inverters which are connected to the grid. Moreover, to estimate the non‐measurable state variables of each local inverter, the derivative‐free nonlinear Kalman filter is used. Furthermore, by redesigning the aforementioned filter as a disturbance observer it becomes also possible to estimate and compensate for disturbance terms that affect each local inverter.