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%。一个典型的海上风电场由数百个兆瓦级风力涡轮机和一个中压交流（MVAC）电网组成，该电网收集来自单个风力涡轮机的电力。由于风机的输出电压过低，无法进行有效的长距离输电，因此每台风机采用专用的低频中压升压变压器，将风机的输出电压升压到MV级。然而，升压变压器体积庞大；重型，通常位于风力涡轮机附近。在文献中，建议将MVAC电网替换为中压直流电网，从而将中压升压变压器替换为中压升压电源变换器。但传统的中压升压电源变换器存在效率低、可靠性差的问题。风电系统中压功率转换中现有的控制器结构是在前端AC/DC级分配一个控制器进行最大功率点跟踪（maximum power point tracking， MPPT），提取风的最大功率，在DC/DC升压转换级分配另一个控制器进行输出电压调节。因此，现有的两级中压风电转换功率效率低，可靠性差，控制结构复杂。***拟议的研究计划是开发新颖高效的电源架构，该架构具有先进的高频中压电源转换器和用于风电场中压电网的数字控制技术。本方案的短期目标是：(1)设计具有高电压增益的新型高频软开关中压功率变换器；（ii）设计新的集成技术，形成新型单级高频中压升压整流器，显著降低功率损耗；（iii）设计新的数字控制器单元，在给定的风和负载条件下同时执行MPPT、输出电压调节和保护功能。虽然概念验证实验原型将在实验室实施和测试以确认所有性能，但长期目标是与工业界合作，进一步将设计的技术开发成用于大功率风力涡轮机的商业产品。本研究项目开发的先进新颖的中压升压电源变换器和控制器将具有开创性，因为它们将显著提高电源效率；大小;大功率风力涡轮机中现有功率变流器的成本和可靠性。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.**