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。

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.