| Give the outstanding advantages of high speed,high precision,large stroke and high dynamic characteristics,permanent magnet synchronous linear motor(PMLSM)can reduce the error caused by the intermediate link,overcome the inherent weakness of "rotary motor + screw" or "rotary motor + gear and rack" and meet the requirements of high precision linear servo drive.It has important application value in various high precision industrial servo fields,such as laser cutting machine,high-grade numerical control machine tool and so onFor the linear motor servo system,a three-loop control(i.e.position,velocity and current)is usually adopted.The inner loop(current loop)is the key component between the control unit and the linear motor,whilst the output thrust is mainly regulated by mover current.Therefore,the current control strategy exerts a significant difference on the high-quality output thrust and precise orientation of the system.In order to obtain high quality thrust and high position bandwidth to improve the tracking accuracy of the system,current closed-loop control needs to ensure high current bandwidth and strong robustness.Therefore,a deadbeat predictive current control algorithm based on adaptive disturbance observer is proposed to improve the dynamic response and anti-disturbance performance of the control system.At the same time,in order to suppress the disturbance caused by the thrust fluctuation and the non-linearity of the inverter,the linear observer and the harmonic oscillator are introduced into the current closed-loop control system to further improve the current control accuracy of PMSLM,so as to achieve the high-precision positioning target of PMSLM.The main contents of the article are as followsFirstly,because permanent magnet synchronous linear motor(PMSLM)is a complex system with strong coupling,multi-variable and non-linearity,in order to better design the advanced PMSLM control strategy,this paper establishes a PMSLM mathematical model in synchronous rotating coordinate system based on coordinate transformation relationship,and then discretizes the obtained model,combining with voltage space vector pulse width modulation technology,deduces PMSLM deadbeat current prediction model.Secondly,two problems of traditional deadbeat predictive control are analyzed:control delay and parameter mismatch.To solve these two problems,deadbeat predictive control algorithm based on adaptive internal model observer and deadbeat predictive control algorithm based on adaptive Luenberger observer are proposed.Among them,deadbeat predictive control algorithm based on adaptive internal model observer mainly combines improved current prediction model with internal model control to improve current prediction accuracy and compensate parameter mismatch disturbance.The deadbeat predictive control algorithm based on adaptive Luenberger observer overcomes the influence of control delay and parameter mismatch by establishing discrete Luenberger observer and estimating the current and disturbance at the next moment.Then,in order to further suppress the non-linear disturbance caused by the non-linearity of the inverter and thrust fluctuation,a resonant predictive controller is designed to suppress the phase current harmonics by combining the resonant regulator with predictive control.Then,based on the dynamic model of PMSLM,a linear observer of the thrust fluctuation of PMSLM is established,which converts the observed thrust fluctuation into current feedforward to current.In the loop,the disturbance caused by thrust fluctuation is compensated.Finally,a PMSML control experimental platform based on hardware-in-the-loop AD5435 is built,and a series of related comparative experiments are carried out.The experimental results show that the deadbeat predictive control based on adaptive disturbance observer proposed in this paper can effectively improve the dynamic response and robustness of current,reduce thrust fluctuation,and improve the positioning accuracy and repetitive positioning accuracy of PMSLM. |
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