海浪发电捕能效率提升关键技术研究

The aim of this research is to improve the capture efficiency of ocean wave energy. The efficiency of direct-driven wave power generation is improved from four aspects, namely, wave power generation device buoy and power generation field distribution, generator design, maximum power extraction, wave power generation Grid-connecting. The energy absorption efficiency of different buoy shapes are studied based on irregular waves. the buoy shape with optimum absorption efficiency can be designed for more energy. For optimal energy absorption efficiency, the distances and angles among generators in wave farm are studied , in which can smooth the output power fluctuations and reduce the masking effects among generators. A new type of high power density TLSRM motor topology is proposed. The phase number and stator / rotor number of the motor are optimized reasonably to achieve high operation performance while considering the high reliability of the wave energy generation system, the light weight of the rotor and the good dynamic response. Based on the dynamical modeling research of the direct-driven wave power generation system, the extraction characteristics of wave energy are analyzed, and the optimal power extraction conditions are obtained. Based on the optimal power extraction conditions, the corresponding power electronic topology, control scheme and control strategy of direct-driven wave generator are proposed. And considering the multi frequency characteristics and time-varying characteristics of ocean waves, the maximum extraction of ocean wave energy of direct drive wave power generation system is realized. The mechanism of power fluctuation and voltage quality is explored when large wave power connecting to power grid. In order to improve the reliability and stability of the power supply in the wave power generation system, the existing control strategy is improved according to the mechanism problem. The super capacitor is used as the energy storage unit, and the method of stabilizing the second short-time power fluctuation of the wave power generation is explored, and combined with the direct-driven wave power generation system, a grid-connecting wave power generation system is formed.

本项目以提高海浪能捕获效率为目标，分别从海浪发电装置浮体及发电场布局、电机设计、最大功率提取、海浪发电并网四方面来提高直驱海浪发电的效率。主要研究内容包括：以不规则波为基础，计算不同形状浮体的能量吸收效率，设计具有最佳吸收效率的浮体形状。基于浮体效应，通过排布优化来平抑单个发电装置的功率波动并削弱遮蔽效应，提升对海浪能的捕获效率。提出一种新型高功率密度柱型直线开关磁阻电机结构，实现高性能运行。通过对直驱海浪发电系统动力学的建模研究，考虑海浪的多频率特性、时变特性，分析其海浪能提取特性，得到最优功率提取条件；基于最优功率提取条件设计对应的电力电子拓扑结构、控制方案和直驱海浪发电机的控制策略，实现直驱海浪发电系统对海浪能量的最大提取。研究海浪发电接入电网时产生功率波动和电压质量问题机理，对现有控制策略进行改进，以提高海浪发电系统供电的可靠性与稳定性。

海浪发电综合的能量转换效率目前还较低，是制约其实现大规模的商业应用的瓶颈之一，项目从装置本体优化、新型发电机设计、功率优化控制算法和海浪发电功率平稳输出四个方面展开研究：（1）研究了典型浮体形状的水动力学系数与海浪能吸收特性，指出“上大下小”型的圆型浮体更易于吸收能量，同时考虑多个海浪发电装置形成阵列后，为提高整体输出功率，应尽量增大排布间距和排布角以削弱浮体间的遮蔽效应；（2）针对海浪发电场，提出了一种利用相位差原理通过设计浮体排布实现功率峰谷互补从而削弱系统的功率波动；针对直驱式波浪发电输出功率具有长短时间尺度波动的特点，采用基于滤波算法功率分配的复合储能平抑功率波动，利用功率型储能来平抑高频功率波动，能量型储能平抑低频功率波动；（3）构造直线开关磁阻电机高阶连续函数模型，以电机效率和功率密度为优化母线对开关磁阻电机结构尺寸进行优化，结合海浪发电功率控制电机控制需求，提出了一种考虑母线电压限制的推力分配函数，实现了电机的四象限运行控制；（4）进一步研究了传统基于谐振原理的控制算法在不规则海浪工况下的应用，分别提出了一种基于速度受迫谐振和一种基于神经网络、无需海浪预测的功率优化控制算法，针对基于时域在线优化的模型预测控制算法，提出了一种基于策略演算的策略和实际控制器上的快速求解算法。项目设计并搭建直驱海浪发电实验测试装置，并在造浪池波浪环境下进行了实验测试，结果表明项目所提的功率优化控制算法在能够实现高效稳定的能量提取。