Advanced high frequency medium voltage power architectures for wind energy systems

到2030年，风能预计将产生至少20%的世界能源需求。全球风能理事会（GWEC）预测，未来4年，全球风电装机容量将增长63%。 典型的海上风电场由数百兆瓦的风力涡轮机和中压交流（MVAC）电网组成，该电网收集来自各个风力涡轮机的电力。 由于涡轮机的输出电压对于有效的长距离电力传输来说太低，所以专用的低频中压（MV）升压Transformer用于每个风力涡轮机以将涡轮机输出电压升压到MV水平。然而，升压变压器体积大、重，并且通常位于风力涡轮机的紧邻处。 在文献中，MVAC电网已经被建议用MV DC电网代替，使得MV升压变压器可以被MV中频升压功率变换器代替。 然而，传统的MV升压功率变换器具有低效率和差的可靠性。 关于在风能系统中的MV功率转换中使用的现有控制器结构，一个控制器被委托给前端AC/DC级用于最大功率点跟踪（MPPT）以从风提取最大功率，而另一个控制器被指定用于DC/DC升压电压转换级以提供输出电压调节。 因此，现有的两级中压风力发电转换的功率效率低，可靠性差，需要复杂的控制结构。* 拟议的研究计划是开发新型高效的电力架构，其特点是先进的高频中压电力转换器和风电场中压电网的数字控制技术。该项目的短期目标是：（i）设计具有高电压增益的新型高频软开关MV功率变换器;（ii）设计新的集成技术，以形成具有显著降低的功率损耗的新型单级高频MV升压整流器;（iii）设计同时执行MPPT的新的数字控制器单元，输出电压调节和保护功能，用于给定的风力和负载条件。* 虽然概念验证实验原型将在实验室中实施和测试，以确认所有性能，但长期目标是与行业合作，进一步将设计的技术开发成用于高功率风力涡轮机的商业产品。 本研究计划中开发的先进和新颖的MV升压功率转换器和控制器将具有突破性，因为它们将显着提高高功率风力涡轮机中使用的现有功率转换器的功率效率，尺寸，成本和可靠性。 此外，这项新技术的成功开发将有助于使加拿大成为可再生能源电力电子研究的全球领导者之一。

By 2030, wind energy is expected to generate at least 20% of the world's energy demand. The Global Wind Energy Council (GWEC), has forecasted that the total installed wind capacity will grow by 63% in the next 4 years. A typical offshore wind farm consists of hundreds of mega-watt wind turbines and a medium voltage AC (MVAC) grid that collects the power from the individual wind turbines. Since the output voltage of the turbine is too low for effective long distance power transmission, a dedicated low frequency medium voltage (MV) step-up transformer is used for each wind turbine to step up the turbine output voltage to the MV level. However, the step-up transformers are bulky; heavy, and typically located in the immediate vicinity of the wind turbines. In literature, the MVAC grid has been suggested to be replaced by a MV DC grid, so that the MV step-up transformers can be replaced by the MV medium frequency step-up power converters. However, the conventional MV step-up power converters have low efficiency and poor reliability. With regards to the existing controller structure used in the MV power conversion in wind energy systems, one controller is delegated to the front-end AC/DC stage for maximum power point tracking (MPPT) to extract maximum power from the wind, while another controller is designated for the DC/DC step-up voltage conversion stage to provide output voltage regulation. Therefore, the existing two-stage MV wind power conversion has low power efficiency, poor reliability and requires complex control structures. ***The proposed research program is to develop novel and efficient power architectures that features advanced high frequency MV power converters and digital control techniques for the MV grid in wind farms. The short term goal of this program is to: (i) devise new high frequency soft-switched MV power converters with high voltage gain; (ii) devise new integration techniques to form a new class of single-stage high frequency MV step-up rectifiers with significantly reduced power losses; (iii) devise new digital controller unit that simultaneously performs MPPT, output voltage regulation and protection function for the given wind and load conditions. ***While proof-of-concept experimental prototypes will be implemented and tested in the laboratory to confirm all the performance, the long-term goal is to collaborate with industry to further develop the devised technology into a commercial product for use in high power wind turbines.  Advanced and novel MV step-up power converters and controllers developed in this research program will be ground-breaking as they will significantly improve the power efficiency; size; cost and reliability of the existing power converters used in high power wind turbines. Furthermore, successful development of this novel technology will help in establishing Canada as one of the global leaders in power electronics research for renewable energy.**