针对石化工艺生产中产量变化时压缩机无法连续调节负荷造成的能量浪费问题，设计了一种基于可编程逻辑控制器（PLC）控制的压缩机负荷连续调节电液系统，主要由S7-300 PLC、电液控制阀、液压驱动器和液压动力单元等组成。系统采用局部行程压开进气阀的控制原理，实现了压缩机负荷在0~100%范围的全量程连续调节，并根据实际工艺流程需求设计了逐级递推式的PID控制回路。该系统能够根据后端工艺的需求自动调节压缩机负荷，保证了工艺量的稳定，同时避免了原打回流方式造成的能量浪费。Abstract：In view of the problem of energy waste caused by the failure of a compressor to continuously adjust its output during a change in a petrochemical process, a continuous regulating electro-hydraulic system based on a programmable logic controller (PLC) has been designed. The main components of the system comprise a S7-300 PLC, electro-hydraulic control valves, hydraulic drivers and a hydraulic power unit. The system adopts releasing the suction valve during a partial stroke as its control principle, and continuous regulation over the range 0-100% can be achieved. In addition, a stage-by-stage recursive PID control method was designed according to the actual process demand. The system can automatically adjust the compressor load according to the demand of the back-end process, thus ensuring the stability of the process quantity, and avoiding any energy waste caused by the original backflow.