LCL Filter with Active Damping using PI and SSI Regulators in Synchronous Rotating Reference Frame Current Controller for DSTATCOM

2013 ◽  
Vol 14 (4) ◽  
pp. 309-326
Author(s):  
Nagesh Geddada ◽  
Mahesh Kumar Mishra
Keyword(s):  
Steady State ◽  
Dynamic Load ◽  
Distribution System ◽  
Voltage Drop ◽  
Active Damping ◽  
Voltage Source ◽  
Lcl Filter ◽  
Load Compensation ◽  
Current Controller ◽  
Load Conditions

Abstract This article proposes a distribution static compensator (DSTATCOM) with interface LCL (inductor-capacitor-inductor) filter for load compensation in three-phase four-wire distribution system. DSTATCOM, consisting of voltage source inverter (VSI), is connected in parallel to the load and injects currents corresponding to load reactive, harmonic powers. But this injected current consists of unnecessary high-frequency switching ripple generated by VSI. This LCL filter has superior switching ripple attenuation capability compared to L filter. Moreover, this can be achieved with small value of overall LCL filter inductance than L filter. Thus providing high slew rate for output current to track the desired reference current closely, reducing voltage drop across it, as well as cost and size of filter. However, one major concern with LCL filter is its resonating frequency (determined from its L, C, L values), which can create high-resonance oscillating currents and results in improper load compensation. Therefore, in this study, proper design of LCL filter with high switching ripple attenuation and a current controller with proportional integral (PI) plus harmonic compensation (HC) regulators along with active damping feature of LCL filter in synchronous rotating reference (dq0) frame are presented. HC regulator minimizes the steady-state error in the non-sinusoidal filter currents (fundamental and harmonic) which are tracked by the VSI. Active damping feature (obtained by capacitor current feedback control of LCL filter) is used to overcome resonance oscillations and provides proper control, operation of DSTATCOM under steady-state and dynamic load conditions. Stability studies for designed LCL filter and current controller using Bode and root locus plots are also performed and presented. Extensive simulation study, to understand the compensation performance of LCL filter DSTATCOM with two types of current controllers (PI and PI plus HC) under steady-state and dynamic load conditions, is carried out in PSCAD simulator and the corresponding results along with THDs of various parameters are presented.

scholarly journals Active damping method for voltage source inverter-based distributed generator using multivariable finite-control-set model predictive control

2021 ◽  
Vol 12 (1) ◽  
pp. 334
Author(s):  
Jonggrist Jongudomkarn ◽  
Warayut Kampeerawat
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Active Damping ◽  
Superior Performance ◽  
Voltage Source ◽  
Lcl Filter ◽  
Grid Voltage ◽  
Grid Current ◽  
Finite Control ◽  
Control Set

Despite its advantages, the LCL filter can significantly distort the grid current and constitute a substantially more complex control issue for the grid-connected distributed generators (DGs). This paper presents an active damping approach to deal with the LCL filter's oscillation for the finite-control-set model predictive control (FCS-MPC)-three-phase voltage source inverters (VSIs)-based DG. The new approaches use the multivariable control of the inverter side's filter current and capacitor voltage to suppress the LCL filter resonance. The proposed method has been tested in steady-state and under grid voltage disturbances. The comparative study was also conducted with the existing virtual resistance active damping approaches for an FCS-MPC algorithm. The study validates the developed control schemes' superior performance and shows its ability to eliminate lower-order grid current harmonics and decrease sensitivity to grid voltage distortion.

scholarly journals Active damping and robust loop shaping control for harmonic minimization

2021 ◽  
Vol 12 (2) ◽  
pp. 832
Author(s):  
Oscar Andrew Zongo ◽  
John Mbogo Kafuku
Keyword(s):  
Active Damping ◽  
Photovoltaic System ◽  
Voltage Source ◽  
Nonlinear Load ◽  
Lcl Filter ◽  
H Infinity ◽  
Integral Control ◽  
Grid Current ◽  
Harmonic Currents ◽  
Loop Shaping

This paper presents an h-infinity robust loop shaping control and LCL filter to mitigate the effects of harmonic currents in the photovoltaic system integrated with the grid. To eliminate the negative effects of the LCL filter, this work applied notch filter active damping. Existing methods for the elimination of harmonic currents were reviewed. Proportional integral control, fuzzy logic control, h-infinity control, and robust loop shaping control are presented. The grid current was analyzed in the system with all controllers applied to control the voltage source inverter of the system to eliminate harmonics in the grid current caused by the inverter and nonlinear loads for two cases, one being constant loading of the linear and nonlinear load and another is the switching of the nonlinear load during the simulation. The results obtained from the proposed method for the two tests conducted were compared with those from other methods to prove the robustness of the proposed technique. The method manages to reduce the total harmonic distortion of the grid current from 7.85% to 0.79% for case 1 and from 11.67% to 1.14% for case 2.

scholarly journals Design of Multi-loop Current Control Strategies for LCL Filtered Grid-connected PV System

2019 ◽  
Vol 9 (2) ◽  
pp. 3672-3677
Keyword(s):  
Current Control ◽  
Control Mode ◽  
Voltage Source ◽  
Loop Current ◽  
Pv System ◽  
Third Order ◽  
Lcl Filter ◽  
Pv Systems ◽  
Current Controller ◽  
Control Schemes

This paper presents numerous feedback current controller methods for the grid-connected PV systems incorporating with third order LCL filter. The various potential dual-loop feedback current controller schemes for a grid-tied electrical converter and a comparison among these controllers are made based on their performance. The effectiveness of these current controllers are based on various views like performance under polluted grid condition and also the dynamic performance of two control schemes under different transient conditions. A commonly used PI controller are employed in all cases of multi-loop controllers and also the electrical converter used here is operated in voltage control mode. In this work, a third-order low-pass LCL filter is employed to minimize the high order harmonics which are created due to the switching of the converter. The LCL filter is incorporated among the dc-ac converter and the utility grid. Two current regulation techniques are focused here. The design, analysis and the performance of these controllers are briefly discussed in this paper. By comparing their performance, anyone can suggest their applications in the grid-tied PV systems. All the current control schemes are incorporated with a grid-connected system of 2-KVA voltage source inverter. Simulation results are produced to validate the performances of two current control schemes. The output ohmic resistance of VSI is taken into account here for their performance analysis.

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