Second Order Sliding Mode Control of Oscillating Water Column Wave Energy Converters for Power Improvement
Second Order Sliding Mode Control of Oscillating Water Column Wave Energy Converters for Power Improvement
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DOI：
10.1109/tste.2020.3035501
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发表时间：
2021-04
影响因子：
8.8
通讯作者：
D. Gaebele;M. Magaña;T. Brekken;J. Henriques;A.A.D. Carrelhas;L. Gato
中科院分区：
文献类型：
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作者：
D. Gaebele;M. Magaña;T. Brekken;J. Henriques;A.A.D. Carrelhas;L. Gato
海浪能是一种可再生能源，但对于大规模发电来说成本太高。振荡水柱（OWC）波能转换器（WEC）是一种很有前途的装置类型，它由整流空气涡轮和发电机组成，将水运动引起的交变气流转化为动能再转化为电能。在能量转换的各个阶段进行控制，可以增加装置的电能输出。随着研究人员克服了空气可压缩性和动力起飞（PTO）动力学引起的非线性等OWC建模挑战，我们可以集成特定的控制算法来测试它们提高OWC效率的能力。本文建立了具有非线性PTO动力学的受升荡运动约束的OWC wcs阵列的状态空间模型。采用二阶滑模控制（SMC）对直驱发电机发出平滑转矩信号以保持参考涡轮角速度。由于该算法可以产生较高的涡轮转矩，因此我们研究了一种简单的前馈关系，用于控制阀门以限制涡轮气流并丢弃机械功率。我们发现，在能量较低的海况下，采用SMC算法和阀门控制可以最有效地提高电能转换。
Ocean wave energy is a renewable energy which remains too costly for large-scale electricity generation. The oscillating water column (OWC) wave energy converter (WEC) is a promising device-type with a rectifying air turbine and generator which convert alternating airflow induced by the water motion into kinetic energy then into electric energy. Applying control at each stage of energy conversion could increase the electric energy output of the device. As researchers overcome the modeling challenges of OWC, such as the nonlinearities due to air compressibility and power take-off (PTO) dynamics, we can integrate specific control algorithms to test their ability to improve the efficiency of the OWC. Herein, we present a state-space model of an array of OWC WECs restricted to heave motion with nonlinear PTO dynamics. We apply second-order sliding mode control (SMC) which commands a smooth torque signal to a direct-drive generator to maintain a reference turbine angular velocity. Because the algorithm can yield high turbine torques, we investigate a simple feed-forward relation for the control of a valve to limit the turbine airflow and discard mechanical power. We find that implementing the SMC algorithm and valve control can improve electric energy conversion most effectively in less energetic sea states.