A Reliable Medium-Voltage High-Power Conversion System for MWs Wind Turbines
A Reliable Medium-Voltage High-Power Conversion System for MWs Wind Turbines
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DOI：
10.1109/tste.2019.2910501
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发表时间：
2020-04
影响因子：
8.8
通讯作者：
Yonglei Zhang;Xibo Yuan;Mo Al-akayshee
中科院分区：
文献类型：
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作者：
Yonglei Zhang;Xibo Yuan;Mo Al-akayshee
随着大型风力发电机组额定功率的不断提高，中压功率转换以更低的电流水平提供更高的功率密度和效率，越来越受到人们的关注。本文评估了一种基于级联模块变换器的中压容错模块大功率转换系统的实际性能。为了避免大量电容器组，通过在控制回路中添加频率自适应准谐振控制器来平衡h桥整流器和三相逆变器之间的功率流，从而衰减每个单元中的低频电压/功率纹波。这样可以提高系统的可靠性，降低系统的成本和体积。在实验评估中，电网侧逆变器出现了意外的包络振荡问题。分析发现，上述问题是由于不同数字信号处理板上的晶体振荡器存在差异造成的。然后，提出了载波锁相环来消除包络振荡问题。实验结果表明，在不影响电网电流质量的前提下，可以有效地消除直流环节电压纹波。
With the increasing power ratings of large wind turbines, medium-voltage power conversion is drawing more and more attention because it generally offers higher power density and higher efficiency with reduced current levels. This paper evaluates the practical performance of a medium-voltage, fault-tolerant modular high-power conversion system based on cascaded modular converters. To avoid many large capacitor banks, the low-frequency voltage/power ripple in each cell has been attenuated through balancing the power flow between the H-bridge rectifier and the three-phase inverter by adding a frequency-adaptive quasi-resonant controller in the control loops. This can improve the system reliability and reduce the system cost and volume. In the experimental evaluation, an unexpected envelope oscillation issue was observed at the grid-side inverters. It was found that the above issue is caused by the discrepancy of the crystal oscillators on different digital signal processor boards. Then, a carrier-wave phase-locked loop has been proposed to eliminate the envelope oscillation issue. Experimental results of a downscaled three-phase five-level modular wind energy conversion system show that the dc-link voltage ripple can be eliminated without affecting the grid current quality.