Research On The Scalar V/F Control Method For Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor(PMSM)has remarkable advantages,such as high power density,high efficiency and fast dynamic response,so it is widely used in the fields of compressor,gas turbine,flyw heel energy storage and aero engine testing.The vector control uses the rotor position information to control the permanent magnet synchronous motor accurately.The encoder is often used in the industry to obtain the rotor position,but the encoder can no t be installed in the high-speed application.Therefore,it is very important to study the PMSM sensorless control method.At present,based on the the parameters of the motor to estimate the position of the rotor flux is the most common PMSM sensorless control method,but with the increase of speed and power,the carrier ratio of the control system decreases,and the frequency of each fundamental modulation is reduced,resulting in the control delay,the smaller the carrier ratio and the larger the lag a ngle.When the lag is too large,the rotor position in the dynamic process can not be estimated,the orientation error of the magnetic field is increased,the dynamic performance of the system is deteriorated,the current oscillates,and even result in the motor out of control.V/F control mode does not need magnetic chain observation information to realize the control of the motor,but PMSM has inherent instability under the traditional open loop V/F control.Therefore,this paper deeply studies the perman ent magnet synchronous motor scalar V/F control system.First,this topic introduces the own characteristics of permanent magnet synchronous motor and introduces the development of the main control technology of PMSM.Aimed at the problem that the vector control method is easy to increase the error of the magnetic chain observation error under the low carrier ratio conditions,the background and significance of the research on the PMSM scalar V /F control without magnetic chain observation are brought out i n this paper.Based on the basic principle of coordinate transformation,the traditional open loop control system is built and its stability is analyzed.It is concluded that the open loop V/F control system of permanent magnet synchronous motor has the ch aracteristics of weak damping or without damping.Secondly,a scalar V/F control method for PMSM is designed,which includes three parts: stator voltage calculation,V/F curve selection and damping regulation.The V/F control curve is optimized by taking consider of the stator resistance voltage drop in the stator voltage amplitude calculation segment.The stability can be enhanced by damping adjustment segment,according to calculating the active power by the stator sampling current and the calculating voltage.The active power disturbance is modulated by a certain algorithm to get the electrical frequency disturbance,and the feedback to the input frequency end is a frequency negative feedback damping adjustment ring,which the active power disturbance can be obtained by the high pass filter.Finally,based on the Matlab/Simulink platform,a simulation model of the scalar V/F control system for permanent magnet synchronous motor is built,and the simulation experiment of accelerated starting and anti load d isturbance of PMSM is carried out by using the control system model.And using the TMS320F2808 chip of TI company,the software program of the algorithm described in this paper is designed with the CCS3.3 development platform,and the experimental device p latform of the PMSM scalar V/F control system is set up.Based on this experiment device,the control system is debugged,analyzed and tested.The experimental results show that the scalar V/F control method in this paper can effectively improve the operat ion stability of PMSM and widen the speed range of motor.