Parallel interfacing converters under unbalanced voltage: Active power oscillation cancellation with peak current sharing

2016 ◽  
Author(s):  
Farzam Nejabatkhah ◽  
Yunwei Li
Keyword(s):  
Active Power ◽  
Peak Current ◽  
Power Oscillation ◽  
Current Sharing ◽  
Unbalanced Voltage

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.

An Optimum UPQC with Minimum VA Requirement and Mitigation of Unbalanced Voltage Sag

2005 ◽  
Vol 2 (2) ◽  
Author(s):  
Y. Y. Kolhatkar ◽  
S. P. Das
Keyword(s):  
Active Power ◽  
Voltage Sag ◽  
Dynamic Voltage Restorer ◽  
Active Power Filters ◽  
Power Filters ◽  
Voltage Restorer ◽  
Unbalanced Voltage ◽  
Dynamic Voltage ◽  
Simulation Results ◽  
Power Quality Conditioner

The paper deals with an optimized Unified Power Quality Conditioner (UPQC), which aims at the integration of series active and shunt active power filters with minimum VA loading of the UPQC. The series active filter is a Dynamic Voltage Restorer (DVR), which is operated in twofold functioning mode. During the unbalanced voltage sag, the DVR compensates the unbalance in the voltage sag. It also regulates the voltage at the load end with minimum VA loading of the overall UPQC by optimum angle voltage injection. Validity of the proposed scheme is proved through extensive simulation results.

scholarly journals Control Scheme Using Active Power Regulation for DC Voltage of VSC HVDC Under Unbalanced Voltage

2015 ◽  
Vol 64 (2) ◽  
pp. 232-239 ◽  
Author(s):  
Sang-In Park ◽  
Jae-Sun Huh ◽  
Won-Sik Moon ◽  
Doo-Hee Kim ◽  
Jae-Chul Kim
Keyword(s):  
Active Power ◽  
Dc Voltage ◽  
Control Scheme ◽  
Power Regulation ◽  
Unbalanced Voltage

scholarly journals Enhanced Current Reference Calculation to Avoid Harmonic Active Power Oscillations

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4075 ◽  
Author(s):  
Javier Serrano ◽  
Javier Moriano ◽  
Mario Rizo ◽  
Francisco Dongil
Keyword(s):  
Harmonic Distortion ◽  
Low Frequency ◽  
Active Power ◽  
Computational Time ◽  
Time Step ◽  
Peak Current ◽  
Current Harmonic ◽  
Grid Voltage ◽  
Current Reference ◽  
Power Oscillations

Energy storage systems play a key role in the rise of distributed power generation systems, hence there is great interest in extending their lifetimes, which are directly related to DC current ripple. One of the ripple sources is the low-frequency active power fluctuations under unbalanced and distorted grid voltage conditions. Therefore, this paper addresses a multifrequency control strategy where the harmonic reference currents are calculated to reduce harmonic active power oscillations. The stationary reference frame (StRF) approach taken here improves the precision and computational time of the current reference calculation method. Additionally, in order to ensure safe converter operation when a multifrequency reference current is provided, a computational efficient peak current saturator is applied while avoiding signal distortion every time step. If the injected current harmonic distortion is to be minimized, which is a feature included in this work, the peak current saturator is a necessary requirement. Active power ripple is reduced even with frequency variations in the grid voltage using a well-known frequency-adaptive scheme. The simulation and experimental results prove the optimized performance for the control objective: power ripple reduction with minimum current harmonic distortion.

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