Development of controllers for renewable energy conversion systems with power quality improvement

风能由于其免费可用、清洁和可再生的特点，是最大的 有望在解决世界能源危机中发挥关键作用的能源资源。根据加拿大风能协会(CWEA)的数据，加拿大风能行业已经打破了2009年的年度增长纪录，新增风能装机容量为950兆瓦，截至2010年9月，总装机容量为3499兆瓦。CWEA在其《WindVision 2025》文件中设定了到2025年风力发电占全国发电量的20%或更多的目标。由于风速明显更高和更恒定，规划限制减少，以及陆地上缺乏适合风力发电场的地点，离岸风力发电场正变得非常有吸引力。欧洲在海上风能方面处于领先地位，已安装了830多台涡轮机，并与9个欧洲国家联网。加拿大也开始投资离岸风力发电场，许多项目也在进行中。除了风力固有的间歇性外，在海上远距离输送如此大规模的电力，对系统运营商和风力发电场开发商都构成了挑战。从海上采集点到陆上电网，VSC-HVDC技术与其他输电线路相比具有许多优势，如基于晶闸管的线路换向换流器(LCC)的高压交流输电或高压直流输电。开发先进的控制技术，使海上风电场与陆上电网的并网更加可靠、高效，不存在电能质量问题，变得越来越重要。因此，本研究的目标是：1)构思、分析/评估、制造/测试适用于不同类型海上风电场的VSC高压直流输电系统的换流器/逆变器拓扑结构及其控制(在实时数字仿真器RTDS上进行仿真)。2)在RTDS上模拟陆上电力系统网络。3)开发适当的控制技术，将海上风电场(目标1)与陆上电力系统网络(目标2)相结合。4)综合海上风电场和陆上电网在不同运行条件下的性能评估。

Wind energy, due to its free availability and clean and renewable character, ranks as the most promising energy resource that could play a key role in solving the world energy crisis. According to Canada Wind Energy Association (CWEA), Canada's wind energy industry has already broken its annual growth record in 2009 with 950 MW of new wind energy capacity, with a total capacity of 3499 MW till September 2010. The CWEA in its 'WindVision 2025' document sets a goal of producing 20% or more of the country's electricity from wind power by 2025. Due to significantly higher and more constant wind speeds, reduced planning restrictions, and the shortage of suitable sites for wind farms on the land, off-shore wind farms are becoming very attractive. Europe has held the lead in off-shore wind, having installed more than 830 turbines with grid connections to nine European countries. Canada has also started investing in off-shore wind farms with many projects in line. To transit such bulk power over great distances, in sea, creates challenges for both system operators and wind farm developers, apart from inherent wind's intermittent nature. From the off-shore collection point to on-shore grid, VSC-HVDC technology has many advantages over other transmission links such as, HVAC or HVDC with thyristor-based line-commutated converters (LCC). It is becoming more and more important to develop advanced control techniques so that the integration of off-shore wind farms with the on-shore grid is more reliable, efficient and free from power quality problems. Therefore, the objectives of the proposed research work is 1) to conceive, analyze/evaluate, fabricate/test proper converter/inverter topology and its control for VSC HVDC system (simulated on a real-time digital simulator - RTDS), for various types of off-shore wind farms. 2) to simulate an on-shore power system network on a RTDS. 3) to develop proper control techniques to integrate off-shore wind farms (of objective 1) with an on-shore power system network (of objective 2). 4) Performance evaluations of integrated off-shore wind farms and on-shore power network for various operating conditions.