Robust stability analysis of grid-connected converters based on parameter-dependent Lyapunov functions.
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Date
2017
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Abstract
This paper deals with the problem of robust
stability analysis of grid-connected converters with LCL
filters controlled through a digital signal processor and subject
to uncertain grid inductance. To model the uncertain
continuous-time plant and the digital control gain, a discretization
procedure, described in terms of a Taylor series
expansion, is employed to determine an accurate discrete-timemodel. Then, a linear matrix inequality-based condition
is proposed to assess the robust stability of the polynomial
discrete-time augmented system that includes the filter state
variables, the states of resonant controllers and the delay from
the digital control implementation. By means of a parameterdependent
Lyapunov function, the proposed strategy has as
main advantage to provide theoretical certification of stability
of the uncertain continuous-time closed-loop system, circumventing
the main disadvantages of previous approaches
that employ approximate discretized models, neglecting the
errors. Numerical simulations illustrate the benefits of the
discretization technique and experimental results validate the
proposed approach.
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Keywords
Robust stability analysis, Linear matrix inequalities, Parameter-dependent, Lyapunov function
Citation
BRAGA, M. F. et al. Robust stability analysis of grid-connected converters based on parameter-dependent Lyapunov functions. Journal of Control, Automation and Electrical Systems, v. 28, p. 159-170, 2017. Disponível em: <https://link.springer.com/article/10.1007/s40313-017-0301-7>. Acesso em: 02 out. 2017.