Research On Prediction And Tracking Method Of Axial Balance Electromagnetic Force Of Scroll Machine

In the needs of vehicle refrigeration,heat pump,braking,fuel cell efficient work,etc.,the scroll machine embodies its unique advantages in the form of compressor or expander,and is increasingly concerned by related research and development and application fields.At present,the requirements of high-precision dynamic sealing in the translational and axial directions are very difficult for the design,processing and application of the static vortex disk,which hinders its high cost performance development in the direction of high pressure,large capacity,long life and oil-free.As far as the axial direction is concerned,the axial gas separation force varies greatly with the change of the rotation angle of the main shaft and the gas pressure at the outlet of the compressor.Therefore,to achieve high-performance axial dynamic seal and dynamic precise balance of the dynamic axial gas separation force of the scroll compressor is one of the key problems that need to be solved properly.First of all,this paper introduces the structure of scroll compressor and the background and significance of the research,as well as the existing problems,and puts forward the purpose of this research.The traditional method of axial force balance of scroll compressor is analyzed,and the dynamic balance scheme of electromagnetic scroll compressor is put forward.According to the application demand and internal space structure of target compressor,the structure of axial force compensation electromagnetic coil of scroll compressor is designed.Secondly,in the traditional PID closed-loop control,aiming at the hysteresis phenomenon in the electromagnetic force dynamic tracking control,the PID dynamic electromagnetic force control method is studied.This paper analyzes the influence of different parameter values on the control performance,puts forward the predictive advance tracking PID method which can find the optimal number of advance steps,and compares it with the traditional PID control method.Verify the effectiveness of the predictive tracking control method.Finally,in order to further verify the effectiveness of the axial force balance control of scroll compressor,STM32F407IGT6 is used as the main control chip to realize the electromagnetic force control experiment based on the pressure feedback control strategy.According to the different working conditions of scroll compressor,the improved algorithm control strategy is compared with the traditional algorithm control strategy on the axial force model test platform of scroll compressor.The experimental results show that this method can provide a scheme for the high-performance dynamic balance of the axial force of the scroll machine.The predictive ahead tracking method can effectively improve the control accuracy of electromagnetic force and realize the steady-state tracking of electromagnetic force curve.