Research Of Adaptive Control Technique Of Intelligent Pump Unit For System Energy-saving

The water supply pump unit,composed of centrifugal pumps in parallel,is widely used in all fields of industry and life.At present,the common water supply type is constant pressure mode,relying on regulating frequency to maintain constant pressure of the equipment exit.Due to this mode not taking account of the demand change of pipeline,a larger design margin is usu-ally left.It causes not only energy waste,but also centrifugal pumps deviating from design run-ning conditions,which will influence the efficiency,service life and reliability of centrifugal pumps.Therefore,this paper proposes an adaptive control technique of parallel pump unit,fac-ing system energy-saving.Through establishing the matching model of pumps performance with pipeline network demand and the estimation model of flow,designing optimization method for pumps reliability and energy minimality,realize the reliable operation of energy-saving pump unit.The main contents of this paper are as follows:(1)The pressure control model matching with pipeline demand and the flow estimation model of high precision for parallel pump unit are established,and the improved PID controller with parameter self-tuning is designed,to realize the intelligent variable pressure control.(2)The energy-efficiency control strategy based on the P-Q real-time prediction and condi-tion deviation(high efficient area)constraint is put forward.Through the selection of running pumps and speed matching,the deviated operation problem is solved,to achieve high efficiency and high reliability operation of pumps in the full range of operating conditions.(3)A control system combined PLC and variable frequency drivers(VFDs)is developed.And the control software,based on adaptive variable-pressure control and energy-efficiency op-timization algorithm,is written and completed the test of energy-saving effect in building simu-lation system.(4)Based on the numerical simulation method,the optimization of monitoring point loca-tion and dynamic characteristics of the water supply pump unit are studied.From the aspect of control accuracy and system stability,the improvement basis is provided for the structure and control logic of the pump system.The adaptive variable-pressure control and energy-efficiency optimization technique pro-posed in this paper can realize adaptive control for parallel pump unit facing system ener-gy-saving,which includes the establishment of matching model of pumps performance with pipeline network demand and the estimation model of flow,the energy-efficiency optimization control strategy on the basis of minimizing power consumption and keeping pumps within high efficiency bounds,the pressure control method of adaptive PID algorithm,and the stability im-proved basis by numerical simulation.Besides,the test and evaluation system simulating build-ing is design and build to verify the control program.The results show that the pump unit pro-posed in this paper is more intelligent,more general,and more energy-saving than con-stant-pressure water supply pumps,and the average energy-saving effect reaches 12.96%,up to 28.31%.In addition,the studies in this paper can also provide technical support for step pump unit selection,speed distribution and operating conditions optimization,to ensure the stability of water supply when the system fast responds during variable-pressure control process.