Torque Ripple Suppression Research On PMSM At Low Speed

Cause of permanent magnet synchronous motor torque ripple can be divided intotwo kinds: first, ontology for the generator design and tooth pulse caused by air gapmagnetic field distortion; second, harmonic torque caused by the nonlinearcharacteristics of inverter.These two factors make the motor current high harmonicscontent increase, causing the current waveform distortion, leading to electromagnetictorque ripple,and limit the permanent magnet synchronous motor using range, whichis in high speed range and high control accuracy.Therefore, in-depth study ofinhibition of permanent magnet synchronous motor electromagnetic torque ripple hasbecome the main direction of research scholars both at home and abroad. motor, Tothe problem of high motor electromagnetic torque ripple in low speed, after thesystem analysis and theoretical research, this paper puts forward an improved controlstrategy.The basic working principle and basic mathematical model of Permanent magnetsynchronous motor are analyzed in this paper.Several kinds of commonly used motorcontrol strategy are given at the same time. Based on that theory, the reason of theelectromagnetic torque ripple of permanent magnet synchronous motor is analyzed indetail, the harmonic mathematical model of the permanent magnet synchronous motoris deduced and a simple effective method for extracting and suppress harmonic ispresented. Using Euler-Fourier formula in real time to extract the higher harmoniccomponents in the three phase current and obtain accurate harmonic voltagecomponent injected into the three-phase control voltage of the motor speed system,offset harmonic component in the motor stator current, get to suppress the higherharmonic current, improve motor current waveform effectively, suppress the motorelectromagnetic torque ripple efficiently.For permanent magnet synchronous motor is a time-varying system which isnonlinear, multivariable and strong coupling, the precise mathematical model ofcontrolled object is not established. Motor current waveform is improved Effectively,which presented in this paper.Based on a self-tuning method of PID controllerparameters and the study of fuzzy controller, turn the speed loop PI regulator into theparameter self-tuning fuzzy PID controller. On the basis of PID initial parameters,The controller will determine the size and the direction of the parameter adjustment according to the response of the controlled object on the error E and error change rateEC of the sampling times, form the fuzzy rule model, and achieve the onlineadjustment of PID parameters using fuzzy reasoning and decision. Fuzzy PIDcontroller is easy and flexible, applied in the speed loop control system, whichenhances the system robustness and can enhance motor operation performance tosome extent and improve the smoothness of motor electromagnetic torque.Based on improvement of control strategy above, build a simulation model inMATLAB/SIMULINK environment and compare the simulation results. Then putforward the design of permanent magnet synchronous motor control drive system,which based on the TMS320F2812DSP.System software design scheme and therelated processes are introduced,and applied it to the control platform,which the maincontrol chip is TMS320F2812.Some experiments about the harmonic control and theeffect fuzzy PID control were done. Experimental results and analysis show that thecontrol strategy is effective, which has use value in engineering application.