不同典型控制策略下有机朗肯循环系统的动态运行特性研究

Study on dynamic operating characteristics of Organic Rankine Cycle system under different typical control strategies

实际热源普遍存在不稳定的特点,不利于有机朗肯循环的稳定和高效运行。因此,采用一定的控制策略使有机朗肯循环系统尽可能适应非稳态余热源的变化,对提高有机朗肯循环的余热回收效率具有重要意义。目前,针对有机朗肯循环的各种控制策略与非稳态热源特性的关系的研究较少,根据实际热源特性选择合适控制策略的理论依据依然缺乏。针对这一问题,本文选择了MAP主动控制、PID控制、MAP主动控制结合PID控制这三种典型控制策略,通过遗传算法优化了控制参数,并探究了采用这三种控制策略时有机朗肯循环在不同热源条件下的动态运行特性。结果表明,当热源波动较平缓或热源发生阶跃变化时,主动控制与PID控制结合的策略能更好地控制系统状态;而当热源波动剧烈时,PID控制策略下工质的过热度能更好追随目标值。

Actual heat sources are generally unsteady,which is bad for the stable and efficient operation of the Organic Rankine Cycle.In order to improve the efficiency of waste heat recovery of the Organic Rankine Cycle,it is necessary to make the Organic Rankine Cycle system adapt to unsteady heat sources by using some control strategies.At present,there are few researches on the relationship between various control strategies of the Organic Rankine Cycle and the characteristics of unsteady heat sources,and the theoretical basis for selecting suitable control strategies according to the characteristics of actual heat sources is still lacking.To solve the problem,three typical control strategies,i.e.,MAP control,PID control,and MAP+PID control,are investigated in this paper.The control parameters are optimized through genetic algorithm,and the dynamic operating characteristics of the Organic Rankine Cycle system with these control strategies are studied under different heat source conditions.The results show that when the heat source fluctuates smoothly or when the heat source undergoes a step change,the strategy of MAP+PID performs better;when the heat source fluctuates sharply,the superheat degree of the working fluid can better follow the set value with PID control.