Some Controlling Strategies of DFIG to the Grid Turbulence

2013 ◽  
Vol 291-294 ◽  
pp. 541-543
Author(s):  
Huan Wang ◽  
Lei Pan
Keyword(s):  
Control Strategy ◽  
Tracking Control ◽  
Dynamic Performance ◽  
Synchronous Generator ◽  
Active Power ◽  
Current Control ◽  
Grid Turbulence ◽  
Dynamic Adjustment ◽  
Stator Current ◽  
Speed Fluctuation

The paper introduces several methods about controlling strategies of DFIG to the gird turbulence. They could reduce the torque pulsation. They have better dynamic adjustment performance than the positive, negative sequence dual current control strategy. Stator current THD is well controlled. The experimental results show that it can smooth the DFIG active power output comparing with the traditional maximum wind energy tracking control strategy, significantly reduces the speed fluctuation of synchronous generator. The dynamic performance is improved.

A Control Strategy for the Grid-Side Converter of the Directly-Driven Wind Turbine with PM Synchronous Generator under Unbalanced Grid Voltage

2013 ◽  
Vol 816-817 ◽  
pp. 669-677
Author(s):  
Wei Cai ◽  
Hui Min He ◽  
Jian Wei Wang ◽  
Shao Ze Su
Keyword(s):  
Control Strategy ◽  
Synchronous Generator ◽  
Active Power ◽  
Current Control ◽  
Frequency Oscillation ◽  
Dc Voltage ◽  
Negative Sequence ◽  
Double Frequency ◽  
Grid Side ◽  
Unbalanced Grid

A mathematical model of the full power grid-connecting converter at grid side for permanent magnet synchronous generator (PMSG) under unbalanced grid conditions is built, double-frequency oscillation mechanism on DC voltage is analyzed, and the influence of active power ripple of grid-connecting impedance on dual current control is discussed. To suppress the double-frequency oscillation on DC voltage, and take the grid-connected impedance on active power into account, a dual current control strategy, which based on respectively orientating positive-and negative-sequence voltages,is proposed, and introduced the correction value of active power ripple of grid-connecting impedance to correct reference current of proposed control strategy. Simulation results show that the proposed control strategy can effectively control positive and negative-sequence currents,eliminate the DC voltage double-frequency oscillation,and improve harmonic characteristic of grid-connected current.

scholarly journals Research and improvement of current control strategy of active power filter

2020 ◽  
Vol 619 ◽  
pp. 012069
Author(s):  
Huajun Wu ◽  
Yupeng Wang ◽  
Bo Liu ◽  
Lidong Chen ◽  
Gen Pei
Keyword(s):  
Control Strategy ◽  
Active Power Filter ◽  
Active Power ◽  
Current Control ◽  
Power Filter

scholarly journals An Autonomous Power-Frequency Control Strategy Based on Load Virtual Synchronous Generator

Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 433 ◽  
Author(s):  
Jiangbei Han ◽  
Zhijian Liu ◽  
Ning Liang ◽  
Qi Song ◽  
Pengcheng Li
Keyword(s):  
Power Systems ◽  
Dynamic Stability ◽  
Control Strategy ◽  
Load Capacity ◽  
Frequency Control ◽  
Synchronous Generator ◽  
Active Power ◽  
Power Oscillation ◽  
Power Frequency ◽  
Virtual Synchronous Generator

With the increasing penetration of the hybrid AC/DC microgrid in power systems, an inertia decrease of the microgrid is caused. Many scholars have put forward the concept of a virtual synchronous generator, which enables the converters of the microgrid to possess the characteristics of a synchronous generator, thus providing inertia support for the microgrid. Nevertheless, the problems of active power oscillation and unbalance would be serious when multiple virtual synchronous generators (VSGs) operate in the microgrid. To conquer these problems, a VSG-based autonomous power-frequency control strategy is proposed, which not only independently allocates the power grid capacity according to the load capacity, but also effectively suppresses the active power oscillation. In addition, by establishing a dynamic small-signal model of the microgrid, the dynamic stability of the proposed control strategy in the microgrid is verified, and further reveals the leading role of the VSG and filter in the dynamic stability of microgrids. Finally, the feasibility and effectiveness of the proposed control strategy are validated by the simulation results.

Research on Predictive Current Control for Three-Level Four-Leg APF

2014 ◽  
Vol 1049-1050 ◽  
pp. 767-770
Author(s):  
Wen Bao Hou ◽  
De Lu Li
Keyword(s):  
Mathematical Model ◽  
Theoretical Analysis ◽  
Control Strategy ◽  
Neutral Current ◽  
Active Power Filter ◽  
Active Power ◽  
Current Control ◽  
Simulation Research ◽  
Power Filter ◽  
Voltage Balance

Taking three-level four-leg active power filter (APF) as research object, this paper establishes the corresponding mathematical model. In addition, the paper establishes the Matlab model based on predictive current control strategy, and then the theoretical analysis and simulation research are conducted. The simulation and experimental results show that the APF with predictive current control strategy can compensate harmonic current and neutral current well and make the two capacitors voltage balance effectively.

scholarly journals A random PWM control strategy for a three level inverter used in a grid connected photovoltaic system

2020 ◽  
Vol 11 (3) ◽  
pp. 1547
Author(s):  
Kamal Himour ◽  
K. Iffouzar
Keyword(s):  
Control Strategy ◽  
Control Structure ◽  
Active Power ◽  
Current Control ◽  
Multilevel Inverter ◽  
Photovoltaic System ◽  
Control Power ◽  
Control Signals ◽  
Simulation Results ◽  
Photovoltaic Generators

<p>The work presented in this paper is devoted to the control of a photovoltaic system connected to grid by a three level diode clamed inverter. A control structure based on three parts: dc link voltage control, power injected control and current control is proposed. In this work, the random PWM strategy is used to generate control signals for the multilevel inverter used us an interface to connect photovoltaic generators to the grid. Numerical simulations are performed using MATLAB / Simulink software, the simulation results for the proposed system indicate  the performances of the proposed control structure, minimization of harmonics by the random PWM strategy applied and injection to the grid more active power by the multilevel inverter structure.</p><p> </p>

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