燃气机热泵改变制冷剂流量的增益调度控制

Gain Dispatchment Control of a Gas-engine-driven Heat Pump by Changing the Flow Rate of Its Refrigeration Agent

燃气机热泵可以通过改变燃气机转速调节系统容量,系统容量的调节和压缩机转速的变化,需要电子膨胀阀调节制冷剂流量与之相匹配。采用实验方法建立蒸发器过热度模型,通过理论分析和实验测试,研究了燃气机热泵系统变转速调节和当过热度设定值改变时蒸发器过热度的控制策略。提出采用增益调度控制策略实现蒸发器过热度的控制,实验结果表明:改变燃气机转速时,过热度控制比较精确,波动范围在±0.5℃以内;过热度设定值改变时,最大超调量小于2℃,过热度响应速度快,具有很好的动态响应特性,达到稳态的时间不超过200 s。

The systematic capacity of a gas-engine-driven heat pump can be regulated by changing the rotating speed of the gas engine.However,the regulation of the systematic capacity and the change of the rotating speed of the compressor are necessarily matched with the electronic expansion valve taking an action to regulate the flow rate of the refrigeration agent.By adopting an experimental method,the authors established a model of the superheating degree of an evaporator and through a theoretical analysis and experiment testing,studied the variable rotating speed regulation of a gas-engine-driven heat pump system and the tactics for controlling the superheating degree of the evaporator when the set value of the superheating degree is being changed.The gain dispatchment control tactics were used to realize a control of the superheating degree of the evaporator.The test results show that when the rotating speed of the gas engine is being changed,the control of the superheating degree is relatively precise with its fluctuation varying in a range of ±0.5 ℃.When the set value of the superheating degree is being changed,the maximal overshoot of the superheating degree is less than 2 ℃ and the superheating degree response is quick.The system displays very good dynamic response characteristics with its time for attaining a steady state being not longer than 200 s.