Article Details

Abstract

To address the practical issues of severe harmonic pollution, three-phase current imbalance and frequent power supply fluctuations in the power grids of high-altitude pastoral areas in China, this paper designs a multifunctional bidirectional inverter integrating the functions of a three-phase voltage-type PWM rectifier, a grid-connected inverter and an active power filter. The system supports two operating modes which are energy storage rectification and harmonic compensation. In rectification mode, it modulates the three-phase half-bridge structure through SPWM to achieve stable charging of the DC-side energy storage unit while providing active filtering capability. In filtering mode, the system disconnects the energy storage side interface and adopts an ip-iq harmonic extraction strategy based on the improved Clark transformation and DSOGI algorithm. It combines SRF-PLL phase-locked loop to realize high-precision detection and real-time compensation of grid harmonic and unbalanced currents. The system exhibits good robustness, harmonic suppression capability and dynamic tracking performance in the complex high-altitude environment. It provides strong support for the integration of distributed power sources and power quality optimization in high-altitude areas.

Keywords

bidirectional inverter; high-altitude power grid; harmonic compensation; active power filter; three-phase LCL filter; power quality

References

1. [1] Wang Mengting Research on Rural Distribution Network Planning Based on Electricity Load Safety [D]. Wuhan: Wuhan University of Science and Technology, 2023
2. [2] Zheng Junguan A Brief Analysis of Several Issues Concerning Power Quality in Rural Power Grids [J]. Rural Electrician, 2022, 30 (7): 41
3. [3] Yang Haotian Consider the distributed power generation planning problem to alleviate the three-phase imbalance in the distribution network [D]. Kunming: Kunming University of Science and Technology, 2023
4. [4] Yu Siwen Research on Harmonic and Interharmonic Detection Algorithm for Rural Distribution Network [D]. Shenyang: Shenyang Agricultural University, 2016
5. [5] Xinhua News Agency Opinions of the Central Committee of the Communist Party of China and the State Council on Effectively Promoting the Comprehensive Revitalization of Rural Areas through Learning and Applying the Experience of the "Thousand Village Demonstration and Ten Thousand Village Rectification" Project [EB/OL]. (2024-02-03) https://www.gov.cn/zhengce/202402/content_6929934.htm.
6. [6] CHENG P T，LEE T L. Distributed Active Filter Systems (DAFSs): A New Approach to Power System Harmonics [J].IEEE Transactions on Industry Applications，2006，42（5）：1301-1309.
7. [7] Jin Wei, Li Yongli, Bu Lizhi, etc Research on Multi functional Grid connected Inverter Based on CPT Theory and Repetitive Control [J]. Journal of Electrical Engineering, 2018, 33 (18): 4345-4356
8. [8] Gao Weiqiang Research on Harmonic Control Strategies for Microgrids Based on Capacity Allocation of Multi functional Grid Connected Inverters [D]. Qinhuangdao: Yanshan University, 2022
9. [9] KARIMI H，IRAVANI M R，LEHN P W. Estimation of Symmetrical Components in Active Distribution Networks Using DSOGI [J].IEEE Transactions on Power Delivery，2010，25（4）：2867-2875.
10. [10] LUNA A，RODRÍGUEZ P，TEODORESCU R，et al. Low Voltage Ride Through Strategies for Grid-connected Converters Under Grid Faults [J].IEEE Transactions on Industrial Electronics，2009，56（12）：4853-4862.

About the authors

Shi Boyan (2005-), male, Han ethnicity, from Xuchang, Henan Province, undergraduate studies, research direction: electrical engineering and automation; Chang Wuhao (2005-), male, Han ethnicity, from Pingdingshan, Henan Province, undergraduate studies, research direction: agricultural electrification; Zhao De (2005-), male, Han ethnicity, from Zhengzhou, Henan Province, is currently pursuing a bachelor's degree with a research focus on agricultural electrification; Xie Panting (2005-), female, Han ethnicity, from Guang'an, Sichuan, is currently pursuing a bachelor's degree with a research focus on electrical engineering and automation.