Research On Random PWM Control Method Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous machine(PMSM)is widely used in the emerging technology industry.And the speed regulation of PMSM mainly using the pulse width modulation(PWM)technology.However,the traditional PWM technology will generate high harmonics at a fixed switching frequency and its multiple times.When PWM is applied,the dead zone time shall be set,which will also affect the modulation effect,such as flux linkage deformation,switching loss increase,etc.In order to solve these problems,this paper introduces three new random PWM methods,which can effectively improve the influence of the traditional PWM technology on the motor control system while keeping the motor operation characteristics unchanged.Firstly,the classical PMSM control model and PWM harmonic analysis theory are analyzed,and the random signal analysis theory is introduced.Then,based on the classical PWM control theory,the corresponding randomization is carried out,and the algorithm basis of random PWM,its transfer function and structure design of PI regulator are obtained.Then three methods,random carrier frequency,random dead time and random duty ratio PWM,are proposed respectively.and the corresponding theoretical analysis process,simulation and experimental design process are carried out in turn.At the same time,the power spectrum estimation theory is introduced to analyze the frequency domain characteristics of random signals in the algorithm results.In the process of result verification,this paper first uses Matlab/simulink to build the simulation model,and then uses power spectrum estimation method to analyze the simulation results.The simulation results show that the random method can suppress some high harmonics.At the same time,it is also proved that the three random methods can improve the overall system operation status without affecting the motor operation characteristics.Finally,TMS320F28335 was used to build an experimental platform to complete the experimental verification process of random PWM technology.The experimental results show that the three random PWM methods can suppress the highorder harmonics,slow down the rising trend of hardware temperature and improve the energy transfer efficiency on the basis of not affecting the running characteristics of the motor.