CAJ | 학술논문

目前在太阳能热发电领域，仅有槽式太阳能实现了商业发电，但是槽式太阳能需要实时进行太阳跟踪。为了提高槽式太阳能跟踪精度，该文研制了一种基于可编程逻辑控制器PLC的太阳自动跟踪系统，并采用视日运动轨迹算法主动式跟踪策略，计算出槽式太阳聚光器跟踪太阳的旋转角度，并用该角度产生控制指令驱动液压油缸，实现对南北布置东西跟踪的槽式太阳能聚光器的精确太阳跟踪，选取了4个典型日期分析该跟踪系统在4个典型日期时太阳位置的高度角、方位角、跟踪太阳的旋转角度以及聚光器的旋转角度等数据，研究聚光器的运行特性。应用结果显示，该跟踪控制系统计算的太阳位置算法与国际上比较先进的高精度太阳位置 SPA 计算算法之间的误差在0.12°以内，角度传感器的变送误差在0.044°以内，间歇跟踪驱动最大误差在0.4°以内，经过现场测试整个跟踪系统的误差在0.5°以内。同时，对聚光器的运行轨迹数据分析显示抛物槽式聚光器的全年最大运行速率出现在冬至日的正午时刻，达到0.398°/min。该研究可以为抛物槽式太阳能聚光器的传动机构设计提供理论依据。
목전재태양능열발전영역，부유조식태양능실현료상업발전，단시조식태양능수요실시진행태양근종。위료제고조식태양능근종정도，해문연제료일충기우가편정라집공제기PLC적태양자동근종계통，병채용시일운동궤적산법주동식근종책략，계산출조식태양취광기근종태양적선전각도，병용해각도산생공제지령구동액압유항，실현대남북포치동서근종적조식태양능취광기적정학태양근종，선취료4개전형일기분석해근종계통재4개전형일기시태양위치적고도각、방위각、근종태양적선전각도이급취광기적선전각도등수거，연구취광기적운행특성。응용결과현시，해근종공제계통계산적태양위치산법여국제상비교선진적고정도태양위치 SPA 계산산법지간적오차재0.12°이내，각도전감기적변송오차재0.044°이내，간헐근종구동최대오차재0.4°이내，경과현장측시정개근종계통적오차재0.5°이내。동시，대취광기적운행궤적수거분석현시포물조식취광기적전년최대운행속솔출현재동지일적정오시각，체도0.398°/min。해연구가이위포물조식태양능취광기적전동궤구설계제공이론의거。
Concentrating Solar Power (CSP) systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. Heat transfer fluid is heated by sun rays through the solar concentrator, then used as a heat source for a conventional power plant. A wide range of concentrating technologies has existed; the most developed are parabolic trough collector (PTC), linear fresnel reflector system (LF), power tower, and dish/engine system (DE). Parabolic trough collector is considered as one of the most mature applications of solar energy in these four technologies, which makes it worth developing. Sun-tracking system plays an important role in the development of solar energy applications, especially for the high solar concentration systems that directly convert the solar energy into thermal or electrical energy. High accuracy of sun-tracking is required to ensure that the solar collector is capable of harnessing the maximum solar energy throughout the day. Compared to fixed systems, power output of single-axis and dual-axis tracking systems can increase by 25% and 41% respectively under the same condition. It is clear that an accurate sun-tracking control system can make solar collectors receive more solar radiation energy to improve the solar energy utilization. A good sun-tracking system must be reliable and able to track the sun at the right angle even in the periods of cloud cover. Although the tracking system is more complex and costs higher than the fixed system, increasing the annual output power can reduce cost effectively. As for photoelectric tracking mode, a sun position sensor is used to provide feedback signals to judge where the sun is, but they don’t work on cloudy days because of the lower sensitivity. The stability of the solar tracking system is a key factor to obtain the maximum sunlight from parabolic trough collector. In order to improve tracking stability and accuracy of the parabolic trough collector sun-tracking control system, this paper chose the more reliable hydraulic drive mechanism to match the system and mainly focused on the design of sun-tracking control system and analysis of operational data from the parabolic trough collector sun-tracking system. Based on the existed working platform of parabolic trough collector system with a length of 50 meters, this paper developed a sun-tracking control system for parabolic trough solar collector. Based on programmable logic controller (PLC), active control mode on the trajectory of the sun was adopted, which could calculate the rotation angle of the parabolic trough solar collector and control commands to drive the hydraulic cylinder to achieve real-time tracking of the sun. The system’s basic operating principle, design of sun-tracking, rotation angle algorithm of parabolic trough solar collector and PLC’s programs have been analyzed. Experiments were conducted in the 4 typical dates (March 20, June 21, September 23, and December 22, in 2013). The analytical result showed that sun-tracking errors of parabolic trough solar collector were nearly 0.5°. Compared to more accurate SPA (solar position algorithm) algorithm, calculation error of algorithm to calculate the position of the sun was within 0.12°. The maximum error of intermittent operation tracking mode was within 0.398°. The maximum operating speed of parabolic trough collector in the year appeared at noon on the winter solstice, the maximum operating speed was 0.398°/min, and transmission error of an angle sensor was at 0.044° or less. This study may provide the theoretical basis for mechanical transmission design of parabolic trough collector.