scholarly journals Resonant control of grid-side converter in wind power system under voltage distortion

2017 ◽  
Vol 2017 (13) ◽  
pp. 2072-2076 ◽  
Author(s):  
Xue-mei Zheng ◽  
Song-nan Pang ◽  
He Li
2013 ◽  
Vol 448-453 ◽  
pp. 1727-1731
Author(s):  
Xi Yun Yang ◽  
Li Xia Li ◽  
Ya Min Zhang

The DC bus voltage is key variable for the operation of converter system in a wind power system. When grid voltage drops, a control of the DC bus voltage is needed to keep the smoothness of DC bus voltage for avoiding generator cutting off grid. A combined control method based on the grid voltage information feedforward with a crowbar circuit is proposed for a direct-drive wind power system in the paper. The unbalanced energy of the DC bus can be unleashed by the crowbar circuit during the dropping of grid voltage. At the same time, the output power of motor-side converter can be controlled to decrease according to the grid-side voltage information, and the mechanical speed of wind turbine and generator can be suppressed by the pitch angle regulation when the output power reduces. Thus, the DC-bus voltage can keep smooth. Results based on Matlab/Simulink simulation shows that this method not only improves dynamic response performance of DC bus voltages control, but also reduces the action time of crowbar circuit. It is benefit to the ability of the wind power system riding through the grid fault.


2013 ◽  
Vol 457-458 ◽  
pp. 1363-1370
Author(s):  
Xian Qin Ma ◽  
Jiu He Wang

In order to improve the performance of the converter for restrain the machine-side PWM rectifier load disturbance impact on the output DC voltage in direct-drive wind power system. A hybrid control strategy based on ADRC and the EL model was presented, using ESO to observe and compensate the load disturbances, achieving voltage outer control by ADRC method and comparing with PI control. However, as to grid-side PWM inverter, energy shaping method which based on PCHD model and the IDA-PBC control algorithm is adopted to design passivity-based controller, which is able to make the energy function have the minimum value when inverter is at the desired point, thus improving the stability and the load disturbance-rejection ability for the inverter. Simulation results show that the machine-side PWM rectifier can make the currents and voltages of AC side achieve synchronous, DC voltage can fast-track desired values; grid-side PWM inverter can achieve unity power factor and make the AC current sinusoidal.


2013 ◽  
Vol 448-453 ◽  
pp. 1767-1772
Author(s):  
Xiong Feng He ◽  
Xian Yun Li ◽  
Tong Zhou Ji ◽  
Hao Peng ◽  
Kun Liu

For enhancing low voltage ride though (LVRT) capability, this paper proposes a new protection scheme of series dynamic breaking resistor (SDBR) connected to the grid-side inverter (GSI) of directly driven permanent magnet synchronous generator (D-PMSG) wind power system, which has a lot of advantages such as possessing low cost, simple structure and high reliability. The structure, switching control strategy and matched resistance of SDBR are researched. The proposed scheme was then applied to uplift GSI voltage during a fault, maintain active power delivered to grid, inhibit DC-link overvoltage and GSI overcurrent. The simulation analysis shows that the SDBR can substantially improve the LVRT capacity of D-PMSG wind power system in PSCAD/EMTDC.


Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7685
Author(s):  
Xiangwu Yan ◽  
Wenfei Chang ◽  
Sen Cui ◽  
Aazim Rassol ◽  
Jiaoxin Jia ◽  
...  

A large-scale power system breakdown in the United Kingdom caused blackouts in several important cities, losing about 3.2 percent of the load and affecting nearly 1 million power users on 9 August 2019. On the basis of the accident investigation report provided by the UK National Grid, the specific reasons for the sub-synchronous oscillation of Hornsea wind farm were analyzed. The Hornsea wind power system model was established by MATLAB simulation software to reproduce the accident. To solve this problem, based on the positive and negative sequence decomposition, the control strategy of grid-side converter of doubly-fed induction generator is improved to control the positive sequence voltage of the generator terminal, which can quickly recover the voltage by compensating the reactive power at the grid side. Consequently, the influence of the fault is weakened on the Hornsea wind farm system, and the sub-synchronous oscillation of the system is suppressed. The simulation results verify the effectiveness of the proposed control strategy in suppressing the sub-synchronous oscillation of weak AC wind power system after being applied to doubly-fed induction generator, which serves as a reference for studying similar problems of offshore wind power.


2013 ◽  
Vol 694-697 ◽  
pp. 2143-2148
Author(s):  
Gan Xiao

In the double-fed wind power system, gird voltage sags would result in some serious problems such as a fluctuation of the DC-link voltage, an instantaneous energy feedback from turbine side to grid side, which affected the steady performance of the wind power system. According to these problems, a dynamic feed forward control strategy based on the traditional feed forward control was studied, with an inhibition of above disturbances. MATLAB simulation and DSP experiments verify the effectiveness of the improved control strategy.


To fill the gaps of the double-fed wind power system, this paper conducts a study for the scarcity and integration of social resources. The LF harmonics on the DC and grid sides are surveyed based on the double Fourier transform algorithm, in conjunction with the power balance theory. A study model has also been built herein. The findings show that the calculated values of the HF harmonic components in the DFIG rotor current almost coincide with the simulation results, regardless of whether the wind velocity is 7 m/s or 19 m/s. When the three-phase voltage of the grid is unbalanced, the stator current contains the grid side basebands with LF harmonics of odd times, among which, the fundamental frequency of triple grid side baseband is the most distinct. It is thus clear that the simulation can capture relevant voltage and current data for the wind power system running in the balance and unbalanced states of grid voltages. it is therefore proved that the theoretical analysis is accurate and reliable.


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