【作者】 王明涛；

【导师】 杨昭；

【作者基本信息】 天津大学 ， 制冷及低温工程， 2011， 博士

【摘要】 燃气机热泵是一种高效节能、经济环保的新型供热空调装置,国内外学者对其进行了广泛而深入的研究。本文对燃气机热泵自动控制系统的软、硬件进行了优化和完善,对燃气机热泵的过热度控制机理、燃气机特性和变容量调节的特点进行了研究,提出了适合各子系统的控制策略,实现了燃气机热泵的高效稳定运行。主要研究内容如下:优化与完善了燃气机热泵自动控制系统软、硬件部分,实现了被控变量的精确检测和执行机构的快速响应;采用机理建模与实验建模相结合的方法,建立了燃气机热泵系统各控制回路的控制模型,为实现燃气机热泵的自动控制奠定基础。对蒸发器过热度的控制机理和动态特性进行了理论分析和实验研究,结果表明,压缩机转速是决定制冷剂流量的主要因素,电子膨胀阀的开度应与压缩机转速相匹配。为了补偿压缩机转速变化与蒸发器非线性因素对过热度控制的影响,本文提出了过热度增益调度控制策略,并对其控制效果进行了实验研究,研究表明:增益调度控制策略具有良好的设定值跟踪性能和抗干扰性能。结合燃气机热泵的实际运行工况,根据人工经验和专家知识,将燃气机的运行工况概括为四种典型工况。基于各种工况的运行规律,提出了燃气机转速专家控制策略。建立了燃气机转速控制仿真模型,研究了突加负载、变容量调节和受到干扰等工况下,专家控制的燃气机转速响应过程;并将专家控制策略应用于燃气机转速的实时控制。仿真和实验结果表明:专家控制策略可以有效减少突加负载造成的燃气机转速波动;具有良好的变容量调节特性和抗干扰性能。针对燃气机热泵和串级控制的特点,提出了燃气机热泵变容量调节的串级控制策略,其中主回路控制热泵系统的出水温度,副回路控制燃气机转速。理论分析和实验研究表明:燃气机热泵串级控制系统可以改善燃气机热泵的特性、增强燃气机热泵的抗干扰能力和整体稳定性,较好的适应了燃气机热泵的变容量调节。更多还原

【Abstract】 The Gas Engine-Driven Heat Pump (GEHP) is a high performance and environment-friendly equipment that can provide heating or cooling and many scholars have conducted in-depth study on GEHP. In this paper, we have accomplished software/hardware optimization of control system, studied the superheat control, gas engine dynamics characteristics and the variable volume adjustment on aspects of theory and experiment and proposed control strategy for different control loops. The controllers of GEHP developed in this thesis ultimately provide better transient and steady state performance. The main contents of this paper are as follows:The optimization of software/hardware achieves the aims of accurate detection of the controlled variable and the reduction of the execution time of step motor. Control-oriented dynamic models of GEHP have been developed by using mechanism modeling and experiment modeling methods and validated with test data collected from a fully instrumented experiment system, which lay the foundation for automatic control system of GEHP.The theoretical analysis and experiment study on the evaporator superheat control shows that compressor speed is the main factor in determining refrigerant flow and the opening percentage of electronic expansion valve should match the compressor rotary speed. In order to compensate the effects of changes in compressor speed and evaporator nonlinear characteristics on the superheat control, the gain scheduling control strategy of superheat has been proposed, which ensures safe and stable operation of compressor and provides better transient and steady state performance.The engine operation conditions are summarized as four typical conditions according to expert knowledge and the engine rotary speed expert controller has been designed based on operation rules of different conditions and dynamics characteristics of engine. Simulation study has been carried out under different conditions by using constructed control models and ultimately the expert controller has been applied to engine rotary speed control in a GEHP system experimentally with good dynamic performance. Cascade control strategy has been proposed to achieve capacity adjustment based on the analysis of the characteristics of GEHP and cascade control strategy. The temperature control loop is primary loop and engine rotary speed control loop is inner loop. The simulation and experiment results show that cascade controller of GEHP can improve the GEHP operating characteristics, control effect and robustness, and has good performance over a wide range of operating conditions.更多还原