Guzman, R.; Garcia de Vicuña, J.; Morales, J.; Castilla, M.; Miret, J.
IEEE transactions on power electronics
Vol. 32, num. 7, p. 5637-5650
DOI: 10.1109/TPEL.2016.2605858
Data de publicació: 2016-09-02
Article en revista
This paper presents a robust model-based active
damping control in natural frame for a three-phase voltage
source inverter with LCL filter. The presence of the LCL
filter complicates the design of the control scheme, particularly
when system parameters deviations are considered. The proposed
control method is addressed to overcome such difficulties and
uses a modified converter model in an state observer. In this
proposal, the converter model is modified by introducing a virtual
damping resistor. Then, a Kalman filter makes use of this model
to estimate the system state-space variables. Although the state
estimates do not obviously match the real world system variables,
they permit designing three current sliding-mode controllers that
provide the following features to the closed loop system: a) robust
ande active damping capability like in the case of using a physical
damping resistor, b) robustness because the control specifications
are met independently of variation in the system parameters, c)
noise immunity due to the application of the Kalman filter, and
d) power loss minimization because the system losses caused
by the physical damping resistor are avoided. An interesting
side effect of the proposed control scheme is that the sliding
surfaces for each controller are independent. This decoupling
property for the three controllers allows using a fixed switching
frequency algorithm that ensures perfect current control. To
complete the control scheme, a theoretical stability analysis is
developed. Finally, selected experimental results validate the
proposed control strategy and permit illustrating all its appealing
features.
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