Three Reference Frame Control Scheme of 4 wire Grid-connected Inverter for Micro Grid Under Unbalanced Grid Voltage Conditions

2009 ◽  
Author(s):  
Xianwen Song ◽  
Yue Wang ◽  
Weihao Hu ◽  
Zhaoan Wang
Keyword(s):  
Reference Frame ◽  
Wire Grid ◽  
Grid Voltage ◽  
Control Scheme ◽  
Micro Grid ◽  
Grid Connected Inverter ◽  
Unbalanced Grid

Control for Grid Connected Inverter under Unbalanced Grid Voltage Based on PI-QR Controller

2014 ◽  
Vol 716-717 ◽  
pp. 1648-1653
Author(s):  
Jia Jin Pan ◽  
Yan Cheng Liu ◽  
Chuan Wang ◽  
Qin Jin Zhang
Keyword(s):  
Reference Frame ◽  
Control Strategy ◽  
Control Model ◽  
Grid Voltage ◽  
Synchronous Reference Frame ◽  
Distorted Grid ◽  
Control Scheme ◽  
Grid Connected Inverter ◽  
Typical Model ◽  
Unbalanced Grid

Control strategy under unbalanced and distorted grid voltage is one of the most significant tasks for grid-connected inverter (GCI). In order to guarantee that the grid current meets the related IEEE Std.929-2000, a new control scheme was presented. Firstly, the typical model of GCI was presented. Secondly, the GCI control model based on PI-QR controller in synchronous reference frame (SRF) was built. Finally, the system’s simulation was conducted under distorted and unbalanced grid voltage. The results demonstrate the effectiveness of the presented control strategy.

Modeling and dynamic response of double-feed induction generator and back-to-back converters in unbalanced grid voltage conditions

2019 ◽  
Vol 44 (4) ◽  
pp. 361-372 ◽  
Author(s):  
Ali Mirzakhani ◽  
Reza Ghandehari ◽  
S Alireza Davari
Keyword(s):  
Reference Frame ◽  
Power Plants ◽  
Governing Equations ◽  
Grid Voltage ◽  
Induction Generators ◽  
Wind Power Plants ◽  
Synchronous Reference Frame ◽  
Grid Side ◽  
Unbalanced Grid ◽  
Different Parts

Double-feed induction generators are one of the most commonly used generators in wind power plants. Therefore, studying this type of generators in different grid conditions such as unbalanced grid voltage is of great importance. In this article, double-feed induction generators, in synchronous reference frame, and back-to-back converters are reviewed and modeled. The advantage of this model, compared with previous ones, is that it can be used in unbalanced grid voltage conditions. Hence, different parts of the generator in synchronous positive reference frame are studied and governing equations in such conditions are analyzed. Stator output power, rotor side converters, grid side converters, and electromagnetic torque, mentioned in the model, are analyzed, as well. The model is also applied in balanced conditions. Therefore, the model proposed in this article is perfect for analyzing wind turbine-based power plants with double-feed induction generators. The accuracy of the suggested function was confirmed through simulation.

scholarly journals Grid Voltage Estimation Based on Integral Resonant Current Controller for LCL-Filtered Grid-Connected Inverter without AC Voltage Sensors

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2051
Author(s):  
Thuy Vi Tran ◽  
Kyeong-Hwa Kim
Keyword(s):  
Phase Angle ◽  
Sensorless Control ◽  
State Observer ◽  
Current Control ◽  
Grid Voltage ◽  
Current Controller ◽  
Start Up ◽  
Control Scheme ◽  
Full State ◽  
Grid Connected Inverter

A high reliability of a grid-connected inverter (GCI) system at reasonable cost is a critical requirement for maximizing renewable energy potential in the electrical energy market. Several grid voltage sensorless control approaches have been investigated not only to eliminate the vulnerability of faulty sensors but also to further reduce the GCI commercial price. In this paper, a frequency adaptive integral-resonant full-state feedback current control scheme with the facilitation of a full-state observer is adopted for a grid-connected inductive–capacitive–inductive (LCL) filtered inverter without sensing the grid voltages. The proposed scheme actively damps the filter resonance and ensures the robustness of the inverter system against unexpected severe grid conditions with low cost and simplified hardware construction. The synchronization of the inverter with the main grid is accomplished by the proposed current controller-based grid voltage estimator, in which the grid frequency and phase angle can be detected effectively. In addition, the actual grid voltages are precisely regenerated to ensure the stable performance of the full-state observer. A safe start-up procedure is also presented for the grid voltage sensorless control of the LCL-filtered inverter to avoid a critical overcurrent and long settling time during the start-up instant, offering a stable and reliable inverter system operation with low computational burden. The effectiveness and feasibility of the proposed voltage sensorless current control scheme are validated by the simulation and experimental results under non-ideal grid conditions such as the harmonic distortion, grid frequency variation, and sudden grid phase angle jump.

A control scheme of the VIENNA rectifier with unbalanced grid voltage

2017 ◽  
Author(s):  
Jiajun Liu ◽  
Wenlong Ding ◽  
Han Qiu ◽  
Chenghui Zhang ◽  
Bin Duan
Keyword(s):  
Grid Voltage ◽  
Vienna Rectifier ◽  
Control Scheme ◽  
Unbalanced Grid

Singe-Phase Grid-Connected Inverter Based on Voltage-Oriented Control in Photovoltaic Generation Systems

2013 ◽  
Vol 765-767 ◽  
pp. 2498-2502
Author(s):  
Yong Yang ◽  
Chun Qing Qi ◽  
Ji Suo ◽  
Feng Wen Cao
Keyword(s):  
Feedback Control ◽  
Reference Frame ◽  
Single Phase ◽  
Control Structure ◽  
Current Control ◽  
Control Loop ◽  
Excellent Performance ◽  
Photovoltaic Generation ◽  
Control Scheme ◽  
Grid Connected Inverter

The paper proposes a new control of a transformerless singe-stage single-phase grid-connected inverter in photovoltaic generation systems. The control scheme is mainly based on voltage-oriented control (VOC) with help of second order Generalized Integrator (SOGI). A cascaded control structure with an outer dc link voltage control loop and an inner current control loop is used. The currents are controlled in a synchronous dq reference frame using a decoupled feedback control. The simulated results have proven an excellent performance and verified the validity of proposed system.

scholarly journals Inter-cluster voltage balancing control of a delta connected modular multilevel cascaded converter under unbalanced grid voltage

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Oghenewvogaga J. K. Oghorada ◽  
Li Zhang ◽  
Huang Han ◽  
Ayodele B. Esan ◽  
Mingxuan Mao
Keyword(s):  
Flow Analysis ◽  
Accurate Method ◽  
Voltage Balancing ◽  
Grid Voltage ◽  
Control Scheme ◽  
Cascaded Converter ◽  
Capacitor Voltage ◽  
Injection Methods ◽  
Cluster Methods ◽  
Unbalanced Grid

AbstractA new inter-cluster DC capacitor voltage balancing scheme for a delta connected modular multilevel cascaded converter (MMCC)-based static synchronous compensator (STATCOM) is presented. A detailed power flow analysis of applying negative sequence current (NSC) and zero-sequence current (ZSC) injection methods in addressing the issue of inter-cluster DC voltage imbalance under unbalance grid voltage is carried out. A control scheme is proposed which integrates both inter-cluster methods using a quantification factor QF. This is used to achieve the sharing of the inter-cluster active power between the NSC and ZSC injection methods. An accurate method of determining the quantification factor is also presented. The proposed method offers better sub-module DC capacitor voltage balancing and prevents converter overcurrent. The influence of unbalanced grid voltage on the delta connected MMCC-based STATCOM rating using this integrated cluster balancing technique is investigated. The control scheme is verified with a 5 kV 1.2MVA MMCC-STATCOM using 3-level bridge sub-modules, and the results show the advantages of the proposed method over other inter-cluster methods.

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