Research On Sensorless Control Of Permanent Magnet Synchronous Motor Double PWM Speed Regulating System

Permanent magnet synchronous motor(PMSM)speed control system occupies an important position in the modern industry,which is the power source of the load driven by mechanical energy,its performance directly affects the stability o f the system.In conventional frequency converter speed control systems,the side arm of the rectifier is composed of ordinary diodes.During the actual operation,the power cannot be controlled,and the input current harmonics are seriously polluted,and the energy regenerated in the four-quadrant operation of the motor cannot be fed back to the power grid.The fluctuation of DC bus voltage and the waste of electrical energy have limited its application in industrial production.With the continuous upgrading of power switch components,the double PWM converter topology composed of fully-controlled devices not only satisfies the fourquadrant operation of the motor,but also has high power ratio operation,low harmonic current factor,and bi-directional flow of power.Quantity feedback and dynamic adjustment of DC bus voltage.This paper is a motor speed control system composed of double PWM converters,consisting of two parts: the PWM rectifier side and the motor drive system side.The combination of the DC bus capacitors is between the two.This paper first deduces the variable equations of controlled objects in various phase coordinate systems.Taking the instantaneous power principle as a reference,the direct power control method of PWM rectifier is studied.This part includes three methods.Firstly,the direct power control based on the traditional switching vector table is introduced.Then the predictive control idea is introduced to design a predictive direct power control method based on the finite con trol instruction.The method is unfixed,and each sampling period The disadvantages of a large number of calculations are required.This paper proposes a method of predicting direct power control based on space vector pulse width modulation(SVPWM)technology and effectively solves the above problems.Secondly,the working principle of PMSM vector control is analyzed and simulated.A model reference adaptive observer is designed,and the stability of the observer is verified.Then the stability of the observer is applied to the vector control.The steady-state error of the observed result is large and the torque pulsation is a problem.The input voltage was reconstructed,and the system before and after the improvement was compared after the simulation.The performance of the system was observed and the effectiveness of the algorithm was verified.Finally,the basic topology of the double PWM converter is introduced.The overall control framework of the dual PWM speed regulation system is given,and the bidirectional power flow conditions are qualitatively and quantitatively analyzed.Afterwards,some key issues were expanded and discussed.Based on the idea of coordinated control,a motor-side power feedforward compensation method was proposed.Compared with the independent control,the simulation results achieved the requirements for PMSM four-quadrant operation and frequent state switching.Solved the problem of severe DC bus voltage fluctuations in the system mutation,and achieved a better control effect.