This paper involves a limit cycle oscillator-frequency lock loop(LCO-FLL)based control algorithm for unified power quality controllers-S type(UPQC-S)for compensation of reactive power,to maintain a unity power factor,...This paper involves a limit cycle oscillator-frequency lock loop(LCO-FLL)based control algorithm for unified power quality controllers-S type(UPQC-S)for compensation of reactive power,to maintain a unity power factor,regulate constant voltage at the PCC,mitigate sag,swell and to eliminate harmonics.In this approach,an extraction of fundamental in-phase and quadrature components for the estimation of reference signals are taken from the LCO-FLL circuit.The control LCO-FLL provides a high grade of protection against sag-swell voltages,unbalance loading and harmonics present in the utility grid.In addition to that,it has advantageous characteristics of synchronization with the grid frequency at any previously mentioned conditions without use of phase locked loops or trigonometric functions.Other advantages of the LCO-FLL are to give useful information to estimate fundamental components from a highly polluted grid scenario.The values obtained from the JAYA optimization algorithm are used to fine-tune the proportional integral(PI)controller gains,so that it maintains DC link voltage to the desired level.The mean square error(MSE)is employed as an objective function for optimizing the error between actual and reference values.The control algorithm based on LCO-FLL is developed in MATLAB/Simulink software and it is tested for power conditioning features.展开更多
A frequency lock loop(FLL)based steady state linear Kalman filter(SSLKF)for unified power quality conditioner(UPQC)control in three-phase systems is introduced.The SSLKF provides a highly accurate and fast estimation ...A frequency lock loop(FLL)based steady state linear Kalman filter(SSLKF)for unified power quality conditioner(UPQC)control in three-phase systems is introduced.The SSLKF provides a highly accurate and fast estimation of grid frequency and the fundamental components(FCs)of the input signals.The Kalman filter is designed using an optimized filtering technique and intrinsic adaptive bandwidth architecture,and is easily integrated into a multiple model system.Therefore,the Kalman state estimator is fast and simple.The fundamental positive sequence components(FPSCs)of the grid voltages in a UPQC system are estimated via these SSLKF-FLL based filters.The estimation of reference signals for a UPQC controller is based on these FPSCs.Therefore,both active filters of a UPQC can perform one and more functions towards improving power quality in a distribution network.In addition to the SSLKF-FLL based algorithm,a bat optimization algorithm(based on the echolocation phenomenon of bats)is implemented to estimate the value of the proportional integral(PI)controller gains.The bat algorithm has a tendency to automatically zoom into a region where a promising alternative solution occurs,preventing the solution from becoming trapped in a local minima.The complete three-phase UPQC is simulated in the Matlab/Simulink platform and the hardware is tested under various power quality problems.展开更多
文摘This paper involves a limit cycle oscillator-frequency lock loop(LCO-FLL)based control algorithm for unified power quality controllers-S type(UPQC-S)for compensation of reactive power,to maintain a unity power factor,regulate constant voltage at the PCC,mitigate sag,swell and to eliminate harmonics.In this approach,an extraction of fundamental in-phase and quadrature components for the estimation of reference signals are taken from the LCO-FLL circuit.The control LCO-FLL provides a high grade of protection against sag-swell voltages,unbalance loading and harmonics present in the utility grid.In addition to that,it has advantageous characteristics of synchronization with the grid frequency at any previously mentioned conditions without use of phase locked loops or trigonometric functions.Other advantages of the LCO-FLL are to give useful information to estimate fundamental components from a highly polluted grid scenario.The values obtained from the JAYA optimization algorithm are used to fine-tune the proportional integral(PI)controller gains,so that it maintains DC link voltage to the desired level.The mean square error(MSE)is employed as an objective function for optimizing the error between actual and reference values.The control algorithm based on LCO-FLL is developed in MATLAB/Simulink software and it is tested for power conditioning features.
基金Supported by the Science and Engineering Research Board-New Delhi Project-Extra Mural Research Funding Scheme(SB/S3/EECE/030/2016).
文摘A frequency lock loop(FLL)based steady state linear Kalman filter(SSLKF)for unified power quality conditioner(UPQC)control in three-phase systems is introduced.The SSLKF provides a highly accurate and fast estimation of grid frequency and the fundamental components(FCs)of the input signals.The Kalman filter is designed using an optimized filtering technique and intrinsic adaptive bandwidth architecture,and is easily integrated into a multiple model system.Therefore,the Kalman state estimator is fast and simple.The fundamental positive sequence components(FPSCs)of the grid voltages in a UPQC system are estimated via these SSLKF-FLL based filters.The estimation of reference signals for a UPQC controller is based on these FPSCs.Therefore,both active filters of a UPQC can perform one and more functions towards improving power quality in a distribution network.In addition to the SSLKF-FLL based algorithm,a bat optimization algorithm(based on the echolocation phenomenon of bats)is implemented to estimate the value of the proportional integral(PI)controller gains.The bat algorithm has a tendency to automatically zoom into a region where a promising alternative solution occurs,preventing the solution from becoming trapped in a local minima.The complete three-phase UPQC is simulated in the Matlab/Simulink platform and the hardware is tested under various power quality problems.
