| Permanent magnet synchronous motor(PMSM)has been widely used in key fields such as industrial production,home appliance manufacturing,aerospace and transportation because of its advantages such as low energy consumption,high power density,high efficiency and high performance.At present,the application of traditional PI control in PMSM has been difficult to meet the high performance requirements for motor systems in industrial and precision instrument manufacturing.To this end,this paper takes the surface-mounted PMSM as the research object and applies the sliding mode control,which is insensitive to internal and external disturbances and robust,to the PMSM speed control system to improve the performance in terms of tracking speed and observation accuracy of the system.The specific research work is as follows.First,the current research status of PMSM speed control system,such as speed loop and position sensorless control technology,is briefly summarized,and its rotor structure,mathematical model and vector control are introduced to lay the foundation for the subsequent research.Secondly,an anti-disturbance composite control algorithm is proposed to optimize the analysis of the speed control loop from the perspective of sliding mode variable structure.To address the problems of slow convergence speed and serious chattering in the traditional sliding mode control,a sliding mode controller based on the improved power convergence law is designed.The convergence law combines the advantages of double power convergence law and fast power convergence law,and introduces the segmentation function and hyperbolic tangent function of the sliding mode surface,which can effectively shorten the convergence motion time and suppress the system chattering.Meanwhile,an extended sliding mode disturbance observer is introduced to observe the load disturbance and compensate the disturbance estimation to the output of the sliding mode controller to further improve the anti-interference capability of the system.In addition,the dynamic performance of the system is improved by using a deadbeat predictive current control with delay compensation in the system current inner loop,and a simulation model is built in the Matlab/Simulink simulation platform for verification and analysis.Then,aiming at the problems of increasing system cost,poor observation accuracy and decreasing reliability caused by the use of traditional mechanical sensors in PMSM,the position sensorless control technology is studied and analyzed,and a full-order sliding mode observer based on second-order generalized integrator is proposed to observe the extended back-EMF and improve the systematic observation accuracy.On the basis of the traditional sliding mode observer,the full-order sliding mode observer hides the discontinuous control quantity in the higher-order derivative,which can effectively suppress the sliding mode chattering.However,due to the nonlinearity of the inverter and the spatial harmonics of the magnetic field,the extended back-EMF still contains a large number of harmonic components and noise,and the extended back EMF is filtered by a second-order generalized integrator with good filtering ability,and a normalized phase-locked loop is used to obtain the motor rotor position and speed information.Finally,the experimental platform of the PMSM is built based on the proposed control algorithm,and the hardware design and software design of the experimental platform are introduced in detail,and the experimental verification of the proposed control algorithm is carried out under the conditions of speed and load mutation.The experimental results show that the proposed control algorithm has good anti-disturbance performance and dynamic performance,with high observation accuracy,and can effectively estimate the rotor position and speed information of the motor. |
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