Title :
Design and Implementation of a Robust Current Controller for VSI Connected to the Grid Through an LCL Filter
Author :
Gabe, Ivan Jorge ; Montagner, Vinícius Foletto ; Pinheiro, Humberto
Author_Institution :
Power Electron. & Control Res. Group, Fed. Univ. of Santa Maria, Santa Maria
fDate :
6/1/2009 12:00:00 AM
Abstract :
This paper describes the design and implementation of a discrete controller for grid-connected voltage-source inverters with an LCL filter usually found in wind power generation systems. First, a theorem that relates the controllability of the discrete dynamic equation of the inverter with LCL filter and the sampling frequency is derived. Then, a condition to obtain a partial state feedback controller robust to grid impedance uncertainties and based on linear matrix inequalities is proposed. This controller guarantees the stability and damping of the LCL filter resonance for a large set of grid conditions without requiring self-tuning procedures. Finally, an internal model controller is added to ensure asymptotic reference tracking and disturbance rejection, significantly reducing the impact of grid background voltage distortion on the output currents. Experimental results are presented to support the theoretical analysis and to demonstrate the system performance.
Keywords :
PWM invertors; PWM power convertors; control system synthesis; discrete systems; electric current control; linear matrix inequalities; power filters; power grids; robust control; state feedback; wind power plants; LCL filter resonance damping; LCL filter resonance stability; PWM inverter; PWM power converter; asymptotic reference tracking; discrete dynamic equation controllability; grid background voltage distortion; grid impedance; grid-connected VSI; linear matrix inequalities; partial state feedback controller; robust current controller design; sampling frequency; voltage-source inverter; wind power generation system; Control systems; Controllability; Equations; Filters; Frequency; Inverters; Robust control; Sampling methods; Voltage control; Wind power generation; LCL filters; Grid-connected inverters; linear matrix inequalities; partial state feedback; pulsewidth-modulation (PWM) converters;
Journal_Title :
Power Electronics, IEEE Transactions on
DOI :
10.1109/TPEL.2009.2016097