TorqTidal: Mitigating Torque Pulsations in Tidal Current Turbines

英国在潮汐涡轮机的开发方面处于全球领先地位，潮汐涡轮机在潮汐进出时从水流中提取能量，并将能量转化为电能。这是由于重要的技术潮汐能资源，据估计，在未来的能源系统中，它有可能提供超过5%的英国电力需求。目前，潮汐涡轮机发电的成本比化石燃料发电高出许多倍，甚至比风能和太阳能等更成熟的可再生能源还要高。这部分是由于与潮汐涡轮机相关的资本成本和运维成本的增加。涡轮机从非定常流中经历脉动扭矩，这增加了组件的应力，导致组件过早失效或昂贵的组件过度设计以应对这些额外的应力。许多以前的研究一直关注的是准确建模的负荷在涡轮机上，以便设计组件承受这些负荷。TorqTidal旨在通过主动控制而不是过度设计来减轻潮汐涡轮机中的扭矩脉动以及对涡轮机的后续影响，从而解决这一问题。这将有助于将能源成本降低到更具竞争力的水平。TorqTidal旨在开发控制策略，并在实际流动条件下模拟的双向潮流涡轮机模型中实施这些策略。使用该模型，将研究以下内容：1。控制策略对发电的影响及实现最优控制时无功功率的必要性强电网、弱电网和离网条件下控制策略的性能和储能需求3。转矩脉动如何影响电能质量以及在弱电网和离网条件下对一组涡轮机平滑供电所需的储能大小控制将使用每个潮汐电流转换系统中存在的现有功率转换器阶段来实现，因此不会增加资本成本。施加到涡轮叶片上的扭矩取决于流速和转子速度；因此，本文将研究最优转子转速分布以减轻转矩脉动，并提出控制策略。这将通过实验工作进行验证，将控制算法应用于一个测试平台，该测试平台代表潮汐涡轮机的电力输出系统，以及部署在FloWave盆地的缩放潮汐涡轮机。该测试平台利用数字信号处理器从软件模型中生成电信号，从而可以模拟真实的流程，并将软件中开发的控制算法直接用于硬件。FloWave盆地能够产生可重复的湍流，以便分析涡轮机在不同控制策略下的行为。

The UK is the global leader in the development of tidal current turbines, which extract energy from the flow of water when the tide moves in and out, and converts the energy into electrical power. This is due to the significant technical tidal current energy resource which has been estimated to potentially supply more than 5% of the UK's electricity demand in a future energy system.At present, the cost of electricity generated from tidal current turbines is many times higher than fossil-fuel generation and even the more established renewables such as wind and solar. This is partly due to the increased capital costs and O&M costs associated with tidal turbines. Turbines experience pulsating torque from the unsteady flow which add stresses to components and lead to either premature component failure or costly over-design of components to cope with these additional stresses. Much of the previous research has been concerned with accurately modelling the loadings on the turbine in order the design components to tolerate these loadings. TorqTidal aims to address this by mitigating torque pulsations in tidal turbines, and the subsequent effects on the turbine, through active control rather than over-design. This will help to toward lowering the cost of energy to a more competitive level.TorqTidal seeks to develop control strategies and implement them in a bi-directional tidal current turbine model simulated under realistic flow conditions. Using the model, the following will be investigated:1. How the control strategies affect power generation and the necessity of reactive power in achieving optimum control2. The performance of control strategies in strong-, weak-, and off-grid conditions and the need for energy storage3. How torque pulsations affect the power quality and the size of energy storage required to smooth the power in weak grid and off-grid conditions for an array of turbinesControl will be achieved using the existing power converter stage which is present in every tidal current conversion system, hence there is no increase in capital cost. The torque applied to the turbine blades is dependent on the flow speed and rotor speed; therefore the optimum rotor speed profile to mitigate torque pulsations will be investigated and a control strategy proposed. This will be verified through experimental work that takes the control algorithm and applies it to a test rig that represents the electrical power take-off system in a tidal turbine and also a scaled tidal turbine deployed in the FloWave basin. The test rig utilises digital signal processors to generate electrical signals from software models, which allows realistic flow to be simulated and control algorithms developed in software to be used directly in hardware. The FloWave basin is able to generate repeatable turbulent flow in order to analyse the behaviour of the turbine under different control strategies.