Adaptive Control for Voltage Source Converter Connected to Weak Grid Based on Backstepping Method

2021 ◽

Vol 23 (07) ◽

pp. 678-689

Author(s):

Bilal Ahmad Ganie ◽

◽

Dr. (Mrs.) Lini Mathew ◽

Keyword(s):

Adaptive Control ◽

Stage Structure ◽

Voltage Regulation ◽

Control Technique ◽

Voltage Source ◽

Voltage Source Converter ◽

Current Harmonics ◽

Control Approach ◽

Photovoltaic Array ◽

Static Compensator

This study provides an adaptive control approach of VSC (voltage source converter) coupled with SPV (solar photovoltaic array), in a 3P3W (three-phase three-wire) system with three single-phase non-linear loads having Distributed Static Compensator (DSTATCOM) abilities using P and O (perturb & observe) methodology. The adaptive control technique converges quickly and has a low mean square error. For the correction of power factor and zero voltage regulation modes, the system is studied and simulated. The system’s great efficacy at high voltages is due to its one-stage structure. Grid current harmonics are significantly below the IEEE-519 norm. The suggested system is modeled and simulated with the available sim power system toolbox in MATLAB/Simulink, and the system’s behavior under different loads and environmental circumstances is confirmed.

Download Full-text

Optimal Nonlinear Adaptive Control for Voltage Source Converters via Memetic Salp Swarm Algorithm: Design and Hardware Implementation

Processes ◽

10.3390/pr7080490 ◽

2019 ◽

Vol 7 (8) ◽

pp. 490 ◽

Cited By ~ 3

Author(s):

Yueping Jiang ◽

Xue Jin ◽

Hui Wang ◽

Yihao Fu ◽

Weiliang Ge ◽

...

Keyword(s):

Adaptive Control ◽

Reactive Power ◽

Voltage Source ◽

Voltage Source Converter ◽

Control Performance ◽

Parameter Uncertainties ◽

Nonlinear Adaptive Control ◽

Salp Swarm Algorithm ◽

Operation Conditions ◽

Swarm Algorithm

Voltage source converter (VSC) has been extensively applied in renewable energy systems which can rapidly regulate the active and reactive power. This paper aims at developing a novel optimal nonlinear adaptive control (ONAC) scheme to control VSC in both rectifier mode and inverter mode. Firstly, the nonlinearities, parameter uncertainties, time-varying external disturbances, and unmodelled dynamics can be aggregated into a perturbation, which is then estimated by an extended state observer (ESO) called high-gain perturbation observer (HGPO) online. Moreover, the estimated perturbation will be fully compensated through state feedback. Besides, the observer gains and controller gains are optimally tuned by a recent emerging biology-based memetic salp swarm algorithm (MSSA), the utilization of such method can ensure a desirably satisfactory control performance. The advantage of ONAC is that even though the operation conditions are constantly changing, the control performance can still be maintained to be globally consistent. In addition, it is noteworthy that in rectifier mode only the reactive power and DC voltage are required to be measured, while in inverter mode merely the reactive power and active power have to be measured. At last, in order to verify the feasibility of ONAC in practical application, a hardware experiment is implemented.

Download Full-text

A robust damping method for voltage source converter with LCL filter under weak grid

CSEE Journal of Power and Energy Systems ◽

10.17775/cseejpes.2019.02400 ◽

2020 ◽

Keyword(s):

Voltage Source ◽

Voltage Source Converter ◽

Lcl Filter ◽

Weak Grid

Download Full-text

Analysis of Synchronization Stability for Multi VSCs Parallel-Connected to Weak Grids by Improved Net Damping Criterion

Energies ◽

10.3390/en13133316 ◽

2020 ◽

Vol 13 (13) ◽

pp. 3316 ◽

Cited By ~ 1

Author(s):

Dong Wang ◽

Xiaojie Zhang ◽

Lei Yang ◽

Yunhui Huang ◽

Wei Huang ◽

...

Keyword(s):

Voltage Regulation ◽

Operating Conditions ◽

Voltage Source ◽

Voltage Source Converter ◽

Signal Model ◽

Detailed Model ◽

Weak Grid ◽

Grid Connection ◽

Sensitivity Studies ◽

Stability Enhancement

Recent studies show that the loss of stability for a voltage-source converter (VSC) in weak-grid connection is largely related to its synchronization unit, i.e., the phase-locked loop (PLL). This paper studies the synchronization stability of a system comprised by two VSCs in parallel connection to a weak grid. A reduced transfer function based small-signal model, which can allow for the interactions between PLL and converter outer power controls, is first proposed. Then, an improved net damping criterion is used to analyze the damping and stability characters of such system under various operating conditions and different controller configurations. Compared to the conventional net damping criterion, the used criterion has wider applicability in terms of stability judgment. Case studies show that the studied system tends to be unstable at weak-grid or heavy-loading conditions. The instability can be in the form of oscillations or monotonic divergence, in which, the latter is more likely to occur for the converters without grid voltage regulation capabilities. Besides, the net damping-based sensitivity studies can provide guidance on control tuning or design for stability enhancement. Detailed model-based time domain simulations are conducted to verify the analysis results.

Download Full-text

Modeling and Analyzing the Effect of Frequency Variation on Weak Grid-Connected VSC System Stability in DC Voltage Control Timescale

Energies ◽

10.3390/en12234458 ◽

2019 ◽

Vol 12 (23) ◽

pp. 4458 ◽

Cited By ~ 3

Author(s):

Yang ◽

Yuan

Keyword(s):

Voltage Control ◽

System Stability ◽

Voltage Source ◽

Frequency Variation ◽

Voltage Source Converter ◽

Small Signal ◽

Small Signal Stability ◽

Dc Voltage ◽

Weak Grid ◽

Dc Voltage Control

The effect of frequency variation on system stability becomes crucial when a voltage source converter (VSC) is connected to a weak grid. However, previous studies lack enough mechanism cognitions of this effect, especially on the stability issues in DC voltage control (DVC) timescale (around 100 ms). Hence, this paper presented a thorough analysis of the effect mechanism of frequency variation on the weak grid-connected VSC system stability in a DVC timescale. Firstly, based on instantaneous power theory, a novel method in which the active/reactive powers are calculated with the time-varying frequency of voltage vectors was proposed. This method could intuitively reflect the effect of frequency variation on the active/reactive powers and could also help reduce the system order to a certain extent. Then, a small-signal model was established based on the motion equation concept, to depict the effect of frequency variation on the weak grid-connected VSC system dynamics. Furthermore, an analytical method was utilized to quantify the effect of frequency variation on the system’s small-signal stability. The quantitative analysis considered the interactions between the DC voltage control, the terminal voltage control, phase-locked loop, and the power network. Finally, case studies were conducted, and simulation results supported the analytical analyses.

Download Full-text