基于柔性变拓扑多脉波整流器的大功率风力发电系统若干关键技术研究

As the non-renewable energy dwindling and sustainable concerns about environmental problems prompt the growing emphasis on the development and utilization of renewable energy. Renewable energy such as wind energy usually requires power electronic converter not only has a wide range of operating voltage, but also maintains high efficiency and high reliability. With the power grade increasing, research and engineering applications show that the application of traditional power converter difficult to meet these requirements. To this end, based on the comprehensive analysis of relevant research and participation in the Natural Science Foundation Flexible-Mode Power Converter Theory, research of several key technologies of high-power wind power generation system based on the flexible-topology multi-pulse thyristor rectifier is proposed in this project. A flexible-topology multi-pulse thyristor rectifier (FTTR) is proposed to take place of the conventional PWM rectifier. The proposed multi-pulse FTTR has outstanding advantages in the aspects of withstanding high current and high voltage, reducing the switching losses, improving the power generation efficiency and savings on the cooling costs. By topology switching, the multi-pulse FTTR can operate in different modes, to broaden its operating voltage range while the wind-power generator to maintain a high power factor and low current THD. This project broadens the flexible-topology converter theory to the AC/DC area, and tries to study the use the high efficiency, reliable and wide-voltage-range multi-pulse FTTR in the wind power generation system, so as to speed up the promotion of research and technological development of wind power converter.

不可再生能源的日趋减少和对环境问题的持续关注促使人们越来越重视新能源的开发利用。新能源发电如风力发电通常要求电力电子变流器不仅具有宽范围的工作电压，而且保持高效率和高可靠性。随着机组功率的不断增大，研究和工程应用均表明应用传统变流器很难同时满足上述要求。为此，在综合分析国内外相关研究及参与自然科学基金“变模态变流器理论”的基础上，本项目提出“基于柔性变拓扑多脉波整流器的大功率风电系统若干关键技术研究”：以柔性变拓扑多脉波整流器代替常规的PWM型整流器，在耐高压大电流、降低开关损耗、提高发电效率和节约散热成本上具有突出的优势。通过变拓扑切换使柔性变拓扑多脉波整流器工作在不同的模式，拓宽其工作电压范围，并使发电机保持较高的功率因数和较低的电流THD。项目将柔性变流器的研究领域拓宽到AC/DC，首次将高效率、可靠、宽范围工作的柔性变流器应用于风力发电系统中，促进风力发电变流器的研究和技术发展。

新能源发电场合如风力发电通常要求电力电子变流器不仅具有宽范围的工作电压，而且保持高效率和高可靠性。随着机组功率的不断增大，研究和工程应用均表明应用传统变流器很难同时满足上述要求。本项目提出了“基于柔性变拓扑多脉波整流器的大功率风电系统：以柔性变拓扑多脉波整流器代替常规的PWM型整流器，在耐受高压大电流、降低开关损耗、提高发电效率和节约散热成本上具有优势。通过理论分析结合仿真实验研究，提出了具有混合工作模式的变拓扑切换柔性变拓扑整流器（包含五种工作模式），并提出电流预测控制策略实现拓扑的柔性切换。针对输入电压不平衡问题，提出采样偏置值动态调整策略，每个采样周期自动调整偏置值，确保输入线电压采样信号正负半平面对称。针对多脉波变流器使用的移相变压器油纸绝缘老化及绝缘状态诊断问题，通过分析回复电压谱线与等效电路参数的函数关系，提出回复电压微分解谱法确定其等效电路极化支路数，解决了长期以来变压器等效电路极化支路数难确定的问题，为准确诊断变压器绝缘状态奠定重要基础。最后，研究了柔性变拓扑变流器在风力发电系统中的应用问题，将柔性变流器应用于风力发电系统中，利用柔性变拓扑变流器多工作模式的特点，根据风机风速和输出电压自动切换工作模式，实现高效率、可靠、宽范围工作，促进了风力发电变流器的研究和技术发展。