ABSTRACT

Digital hydraulics is a potential technology for the Hydraulic Pitch System (HPS) in Wind Turbine (WT). Digital Hydraulics Pitch System (DHPS) uses Digital Flow Control Units (DFCU) to develop the precise pitching action. In this paper, a novel Intelligent Digital Pitch Controller (IDPC) is proposed. The proposed controller is designed and implemented on a developed lab-scale DHPS Hardware-in-the-Loop (HIL) simulator. The various parameters of DHPS-hardware were designed using the bottom-up design methodology. The IDPC comprises Machine Learning (ML)-based WECS and DHPS controllers in the outer and inner loop respectively. HIL simulations were conducted with the implemented IDPC. The ML-based WECS controller predicts the reference pitch angle close to its desired value. The ML-based DHPS controller predicts the states of DFCU to develop real-time pitching action in DHPS-hardware. Several case studies were conducted to validate the effectiveness of the proposed IDPC. A study shows that IDPC controlled DHPS exhibits better performance than an ML-Proportional Integral (PI) controlled HPS with proportional flow control valve. Subsequently, the performance of the IDPC is compared with PI-ML cascade controller. This study shows that the Maximum Absolute Error (MAE) between the generator speed and its rated speed is 0.87% and 19.29% for the proposed controller and PI-ML cascade controller, respectively. Similarly, MAE (error between generator torque and its rated torque) of torque is 0.85% and 5.46% for the proposed controller and PI-ML cascade controller, respectively. Thus, the implementation of the IDPC develops optimal power with minimal speed/torque fluctuations.

摘要

数字液压技术是风力涡轮机（WT）中液压变桨系统（HPS）的一项潜在技术。数字液压变桨系统（DHPS）使用数字流量控制单元（DFCU）开发精确的变桨动作。本文提出了一种新型的智能数字音调控制器（IDPC）。拟议的控制器是在开发的实验室规模的DHPS硬件在环（HIL）仿真器上设计和实现的。DHPS硬件的各种参数是使用自下而上的设计方法进行设计的。IDPC分别在外循环和内循环中包含基于机器学习（ML）的WECS和DHPS控制器。使用已实现的IDPC进行HIL仿真。基于ML的WECS控制器预测参考螺距角接近其期望值。基于ML的DHPS控制器可以预测DFCU的状态，从而在DHPS硬件中开发出实时的俯仰动作。进行了一些案例研究，以验证提议的IDPC的有效性。一项研究表明，IDPC控制的DHPS的性能优于带有比例流量控制阀的ML比例积分（PI）控制的HPS。随后，将IDPC的性能与PI-ML级联控制器进行比较。研究表明，对于拟议的控制器和PI-ML级联控制器，发电机转速与其额定转速之间的最大绝对误差（MAE）分别为0.87％和19.29％。类似地，对于所提出的控制器和PI-ML级联控制器，转矩的MAE（发电机转矩与其额定转矩之间的误差）分别为0.85％和5.46％。从而，