Three-phase Sinusoid-locked Loop for the Parameters Estimation of Unbalanced Grid Voltage

To improve the performance of three-phase voltage source pulse-width modulated (PWM) rectifiers (VSR) under unbalanced grid voltage conditions, a fixed-frequency current predictive control (CPC) strategy is presented. Instantaneous power of the three-phase VSR is analysed in a two-phase stationary frame. The calculation method for the reference current is improved to achieve the power stability at the AC side of the rectifier. Based on the current predictive model, the optimal duration of the voltage vectors is computed under the restricted condition of minimizing current error at α- and β-axes in fixed intervals. The control system is free of synchronous rotation coordinate transformation, and avoids positive and negative sequence decomposition, which simplifies the calculation. The simulation and experimental results show that the proposed control strategy is able to eliminate the AC current distortion effectively and depress DC link voltage fluctuation under unbalanced grid voltage. Furthermore, the control strategy has faster dynamic response ability, enhancing the control performance of the three-phase VSR system.

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Finite Control Set Model Predictive Control for an LCL-Filtered Grid-Tied Inverter with Full Status Estimations under Unbalanced Grid Voltage

Energies ◽

10.3390/en12142691 ◽

2019 ◽

Vol 12 (14) ◽

pp. 2691 ◽

Cited By ~ 3

Author(s):

Xiaotao Chen ◽

Weimin Wu ◽

Ning Gao ◽

Jiahao Liu ◽

Henry Shu-Hung Chung ◽

...

Keyword(s):

Model Predictive Control ◽

Predictive Control ◽

Reactive Power ◽

Grid Voltage ◽

Luenberger Observer ◽

Reference Generator ◽

Three Phase ◽

Finite Control ◽

Control Set ◽

Unbalanced Grid

This paper proposes a novel finite control set model predictive control (FCS-MPC) strategy with merely grid-injected current sensors for an inductance-capacitance-inductance (LCL)-filtered grid-tied inverter, which can obtain a sinusoidal grid-injected current whether three-phase grid voltages are balanced or not. Compared with the conventional FCS-MPC method, four compositions are added in the proposed FCS-MPC algorithm, where the grid voltage observer (GVO) and Luenberger observer are combined together to achieve full status estimations (including grid voltage, capacitor voltage, inverter-side current, and grid-injected current), while the sequence extractor and the reference generator are applied to eliminate the double frequency ripples of the active or reactive power, or the negative sequence component (NSC) of the grid-injected current caused by the unbalanced grid voltage. Simulation model and experimental platform are established to verify the effectiveness of the proposed FCS-MPC strategy, with full status estimations under both balanced and unbalanced grid voltage conditions.

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Model Predictive Control of Three-Phase Voltage Source Rectifiers under Unbalanced Grid Voltage Conditions

7th IET International Conference on Power Electronics, Machines and Drives (PEMD 2014) ◽

10.1049/cp.2014.0350 ◽

2014 ◽

Cited By ~ 3

Author(s):

Zhanqing Zhou ◽

Wei Chen ◽

Qiang Geng ◽

Xin Gu ◽

Changliang Xia

Keyword(s):

Model Predictive Control ◽

Predictive Control ◽

Voltage Source ◽

Phase Voltage ◽

Grid Voltage ◽

Three Phase ◽

Unbalanced Grid

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A compound control strategy of three‐phase Vienna rectifier under unbalanced grid voltage

IET Power Electronics ◽

10.1049/pel2.12202 ◽

2021 ◽

Author(s):

Xingtian Feng ◽

Yongming Sun ◽

Xiao Cui ◽

Wenzhong Ma ◽

Yubin Wang

Keyword(s):

Control Strategy ◽

Grid Voltage ◽

Compound Control ◽

Vienna Rectifier ◽

Three Phase ◽

Unbalanced Grid

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Harmonic Injection-Based Power Fluctuation Control of Three-Phase PV Systems under Unbalanced Grid Voltage Conditions

Energies ◽

10.3390/en8021390 ◽

2015 ◽

Vol 8 (2) ◽

pp. 1390-1405 ◽

Cited By ~ 4

Author(s):

Nian-Cheng Zhou ◽

Xiao-Xuan Lou ◽

David Yu ◽

Qiang-Gang Wang ◽

Jia-Jia Wang

Keyword(s):

Power Fluctuation ◽

Grid Voltage ◽

Pv Systems ◽

Three Phase ◽

Harmonic Injection ◽

Unbalanced Grid

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Modified Power Compensation Control Strategy of Three-Phase Grid-Connected Inverter under Unbalanced Grid Voltage Conditions

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.740.335 ◽

2015 ◽

Vol 740 ◽

pp. 335-338 ◽

Cited By ~ 1

Author(s):

Shao Hua Sun ◽

Hong Qi Ben

Keyword(s):

Control Strategy ◽

Reactive Power ◽

Positive Sequence ◽

Grid Voltage ◽

Compensation Control ◽

Active And Reactive Power ◽

Three Phase ◽

Grid Connected Inverter ◽

Three Phase Inverter ◽

Unbalanced Grid

Control strategy under unbalanced grid voltage conditions is one of the most important issues for grid-connected inverter. Under unbalanced grid voltage conditions, the 2nd active and reactive power ripples generate, they pollute the grid. To meet the demands of IEEE Std.929-2000, this paper proposed a modified power compensation control strategy; the proposed solution is based on direct power control. To provide accurate compensating power, the power model of three-phase inverter under unbalanced grid voltage conditions is given, using the positive sequence current component and the negative sequence voltage component, the compensating powers are calculated in details. Theoretical analysis and comparative simulation verification are presented to demonstrate the effectiveness of the proposed control strategy.

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