槽式太阳能热发电储热系统控制策略研究

Research on Control Strategy of Trough Solar Thermal Energy Storage System

储热系统(TESS)是槽式太阳能热发电系统的重要组成部分。由于太阳能资源具有强烈的随机性、间歇性与波动性,为进一步提高系统的整体可靠性,以满足变工况运行的需要,对槽式太阳能储热系统控制策略进行了优化研究。以储热系统中的核心设备油/盐换热器里的熔融盐蓄热工质为重点研究对象,采用比例、积分、微分(PID)控制理论,在MATLAB/Simulink仿真环境下搭建了系统数学模型。利用临界比例度法确定了控制系统中诸多关键参数,整定了PID控制器中的比例系数、积分时间等物理量,并分析了阶跃扰动下比例(P)控制、比例积分(PI)控制、PID控制这3类不同控制系统的各自动态响应特性。仿真对比分析结果表明:较另外2种控制方式,PID控制更能有效地削弱由于外界扰动而引起的储热系统振荡,其动态响应速度更快、调节时间更短,可满足运行稳定性的要求。采用PID控制,降低了槽式太阳能储热系统的控制难度,提高了对外界气象资源变化的适应性。该研究结果在学术与工程层面均有一定的指导意义。

Thermal energy storage system（TESS） is an important part of trough solar thermal power generation system. Due to the strong randomness,intermittent and volatility of solar energy resources, in order to further improve the overall reliability of the system and meet the requirements of variable operating conditions, the optimization of the control strategy for TESS of trough solar energy has been researched. Taking the molten salt heat storage medium in the oil/salt heat exchanger of the core equipment in TESS as the key research object, the proportion integration differentiation （PID） control theory is used to build the system mathematical model in the MATLAB/Simulink simulation environment. The critical proportional method is used to determine many key parameters of the control system, and the physical quantities such as the proportional coefficient and integral time in the PID controller are tuned, as well as the respective dynamic response characteristics of the three control systems of proportion （P） control, proportion integration （PI） control, and PID control under step disturbance are analyzed. Through simulation and comparison analysis, the results show that compared with the other two control methods, PID control can effectively overcome the oscillation of TESS caused by external interferences, and it has advantages of faster response speed, shorter adjustment time and satisfies the requirements of operation stability. Applying PID control will reduce the difficulty of controlling the TESS of trough solar energy and improve the adaptability to changes in the external nleteorological resources. The results obtained have certain guiding significance at the academic and engineering levels.