scholarly journals Research on control strategy for AC side asymmetric fault of MMC-HVDC transmission system

2021 ◽  
Vol 260 ◽  
pp. 02015
Author(s):  
Mingguang Zhang ◽  
Huzhong Sun ◽  
Richang Guo ◽  
Yao Shen
Keyword(s):  
Control Strategy ◽  
Feedback Linearization ◽  
Frequency Component ◽  
Operating Characteristics ◽  
Hvdc Transmission ◽  
Double Frequency ◽  
Voltage Controller ◽  
Long Time ◽  
Linearization Principle ◽  
Negative Sequence Current

When the Modular Multilevel Converter (MMC) fails on the AC side, the operating characteristics of MMC will be damaged. If the system wants to retain stable for a long time in the process of operation, it is obliged to design the control strategy in case of asymmetric fault. In this article, the control strategy based on feedback linearization principle is adopted to diminish the negative sequence current caused by breakdown, and a DC voltage controller is devised to suppress the fluctuation of the double frequency component under asymmetric fault conditions. The validity of the control strategy requires to be verified, the running results on PSCAD platform indicate this method is effective and feasible.

scholarly journals Active and Reactive Power Compensation Control Strategy for VSC-HVDC Systems under Unbalanced Grid Conditions

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3140 ◽  
Author(s):  
Weiming Liu ◽  
Tingting Zheng ◽  
Ziwen Liu ◽  
Zhihua Fan ◽  
Yilong Kang ◽  
...  
Keyword(s):  
Control Strategy ◽  
Disturbance Observer ◽  
Reactive Power ◽  
Operating Conditions ◽  
Voltage Source ◽  
Double Frequency ◽  
Compensation Control ◽  
Active And Reactive Power ◽  
Passivity Based Control ◽  
Unbalanced Grid

This paper presents a power compensation strategy to suppress the double frequency power ripples of Voltage source converter high-voltage direct current (VSC-HVDC) systems under unbalanced grid voltage conditions. The mathematical control equations of the double frequency ripple power of VSC under unbalanced operating conditions are firstly derived and established, where the dynamic behaviors of the double frequency ripples in active and reactive power are regarded as being driven by current-relevant components and voltage-relevant components, respectively. Based on the equations, a power compensation control strategy of VSC-HVDC is proposed via the passivity-based control with disturbance observer to suppress both the current-relevant and voltage-relevant components in the power ripples. With this control strategy, the double frequency ripples in active and reactive power are suppressed simultaneously and system performance is significantly enhanced with the implementation of the disturbance observer in the passivity-based control. Theoretical stability analysis and simulation cases show the effectiveness and superiority of the proposed strategy.

scholarly journals A New Control Strategy for Bi-directional DC/DC Converter in DC Microgrid

2021 ◽  
Vol 233 ◽  
pp. 01051
Author(s):  
Tianze Miao ◽  
Xiaona Liu ◽  
Siyuan Liu ◽  
Lihua Wang
Keyword(s):  
Steady State ◽  
Control Strategy ◽  
Feedback Linearization ◽  
Sliding Mode ◽  
Response Speed ◽  
Fast Response ◽  
Sliding Mode Controller ◽  
Exponential Approximation ◽  
Dc Microgrid ◽  
Simulation Results

The bi-directional DC / DC converter in DC microgrid is a typical nonlinear system which has large voltage disturbance during lead accumulator charging and discharging. In order to solve the problem of voltage disturbance, the linearization of the converter is realized by exact feedback linearization, and the sliding mode controller is designed by using exponential approximation law. The simulation results show that the method has fast response speed, strong anti-interference ability and good steady-state characteristics.

Improved Control Strategy of Wind Turbine with DFIG for Low Voltage Ride through Capability

2014 ◽  
Vol 707 ◽  
pp. 329-332
Author(s):  
Li Ling Sun ◽  
Dan Fang
Keyword(s):  
Wind Turbine ◽  
Control Strategy ◽  
Low Voltage ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Operating Characteristics ◽  
Low Voltage Ride Through ◽  
Doubly Fed ◽  
Rotor Side Converter ◽  
And Control

As the number of doubly fed induction generator (DFIG)- based wind-turbine systems continues to increase, wind turbines are required to provide Low Voltage Ride-Through (LVRT) capability, especially under the condition of grid voltage dips. This paper, depending on the operating characteristics of doubly-fed induction generator during grid faults ,deals with a protection and control strategy on rotor-side converter (RSC) to enhance the low voltage ride through capability of a wind turbine driven doubly fed induction generator (DFIG). The simulation and experiment studies demonstrate the correctness of the developed model and the effectiveness of the control strategy for DFIG-based wind-turbine systems under such adverse grid conditions.

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