Performance Analysis And Control Of Variable Frequency Pump-control-motor System

The variable speed control hydraulic technology has great advantages in reducing energy consumption and improving efficiency,so it is widely used in engineering application fields such as injection molding machine,shield machine and hydraulic elevator.However,the variable speed control hydraulic technology has the disadvantage of slow response,low speed rigidity and low control accuracy.According to the above problem,based on the variable frequency pump-control-motor system,through theoretical analysis,simulation modeling and experimental research,the performance of the variable speed control hydraulic system is analyzed and its speed control and position control are studied in this paper.First of all,based on the reliability experiment platform of hydraulic pump(motor)developed by yanshan university and a company,the variable frequency pump-control-motor system is built.Secondly,the mathematical model of the variable frequency pump-control-motor system is built and the MATLAB/Simulink simulation model of the system is built.Through simulating,the influence of different parameter changes on motor speed and system pressure characteristics is found.Further,this paper analyzes the specific principle of the change of each parameter to the system performance,and put forward some reasonable suggestions for the specific application of variable frequency pump-control-motor system.Then,the control effect on the motor speed of dynamic compensation control,PID control and PID control based on velocity forward is simulated.On the basis of speed control,the control of motor angular displacement is further studied.Simulation results show that all the three control strategies can compensate for the motor speed decreasing caused by the load disturbance;compared with traditional PID control,the PID control based on velocity feedforward has better control characteristics in improving system response speed and control precision,and it has good control effect on the speed and position of the system.Finally,according to the experimental requirements,a simple and practical measurement and control software is developed for the established variable frequency pump-control-motor system,the variable frequency pump-control-motor system is studied experimentally,and the validity of the simulation model and simulation results is verified.