Research On The Control Strategies And Their Syncretized Algorithm For Permanent Magnet Synchronous Motor

Along with the rapid development of power electronics technology,micro-computer technology, rare earth permanent magnet materials science,automatic control theory, intelligent control theory and technology, permanentmagnet synchronous motors (PMSMs) with the advantages such as increasedefficiency, superior torque-to-volume and power-to-volume rations, and quietoperation has been widely used in the motion control system of the industrial,aerospace, defense and military fields. PMSM digital servo system gradually takesthe place of DC motors, stepper motor motion system and becomes the developmentdirection of the servo drive system. However, permanent magnet synchronous motorservo system was influenced by multi variable coupling and parameter variations,external load disturbance, harsh environment and other factors. So permanentmagnet synchronous motor model, the control strategies and the advanced controlmethods must be studied and thoroughly analyzed to achieve high performance,wide speed range, strong environmental adaptability and anti disturbance ability.This paper is aiming at the control strategies of full digital permanent magnetsynchronous servo system, and the main content of the paper is as follows.The electromagnetic process of sinusoidal permanent magnet synchronousmotor, torque angle characteristics are analyzed, and established three coordinates ofthe stator flux linkage equations, the voltage equation and electromagnetic torqueequation, provides the theoretical foil for the analysis of control strategies. At present,the mainstream of control strategies of the sinusoidal PMSM servo control systemsare the rotor flux oriented vector control strategy and the direct torque controlstrategy with stator flux control.With the systematically analysis of the basic principle and implementationmethod of the rotor flux oriented vector control strategy for sinusoidal PMSM, itssimulation model at id=0was set. And the PI controller parameters of the currentloop and speed loop especially the relations of band width and current regulatorparameters were set. To analyze the affect of the performance of speed loop by theinitial zero deviation, the Routh criterion was used to determine the stability of speedloop and simulation and the experimental results showed that the responseperformance and immunity performance of the speed loop would be worse with the increase of the initial zero deviation. Based on summarizing the common limiterstrategy, a new a new clipping method was proposed and theoretical analysis provedthat the method is effective and quality.The principle of direct torque control strategy with stator flux control wasanalyzed and the given mechanism of the amplitude of stator flux linkage on theconventional direct torque control scheme was improved. Simulation results showthat, the new mechanism of the amplitude of stator flux linkage makes the stepresponse performance of electromagnetic torque to achieve optimal.The similarities and differences of the control structure and the step responseperformance of the electromagnetic torque loop between the rotor flux orientedvector control and the stator flux oriented direct torque control was compared andanalyzed. Then the stator flux oriented control algorithm with the voltage spacevector pulse width modulation technology which has fused the advantages of thevector control and the direct torque control was studied. Simulation and experimentsverify the effectiveness of the method and optimal performance of the step response.Finally, a full digital PMSM servo control system was built and validated thevector control algorithm, direct torque control algorithm and the fusion algorithm.The experimental results verify the advantages and disadvantages of three kinds ofcontrol algorithms in a certain extent.A scheme of an angle measurement circuit for the two-speed resolver wasdesigned, which included the decoding and measurement of the precision. A schemeof measurement test is carried out with collimator and prism in the laboratory. Theresults achieve the designed functions of the scheme completely and the error by rmsof the single angle measurement circuit is20arc seconds, which reaches9.46arcseconds after correcting the systemic error with software. Lastly, the causations ofthe systemic error of the angle measurement circuit are indicated in this paper.