Research On The Control Strategy Of Synchronous Reluctance Motor Considering Magnetic Saturation

Synchronous reluctance (SynRM) motors have draw more and more attention andresearch in recent years, due to its permanent magnet-free merit,lower cost than PMSMand smaller torque ripple than SRM determined by operational principle. It isprecondition for achieving high quality control performance to get the accurateparameters in vector control of synchronous motor. As the change of the current, thevariation of d-q inductances caused by the saturation of the main magnetic circuit wouldgreatly affect the control. So it become a hot topic to research on the influence ofmagnetic saturation to vector control.To solve the problem of the influence caused by the variation of parameters whichbrought by the magnetic saturation, make the accuracy of control higher and rapiddynamic response, this paper firstly analyzes the linear mathematic model and thetraditional vector control model of SynRM, and then find out the disadvantages of thetraditional vector control,such as sensitivity to parameters, slow dynamic response.Through the analysis of magnetic saturation effect on parameters, the model forsynchronous reluctance motors is then built, which has incorporated magnetic saturation.Considering magnetic saturation effect, this paper presents a vector-control algorithm,based on the observation of magnetic flux which is analyzed in details. On account ofthe above, an improved MTPA control strategy based on variable step searching isproposed.To verify the correctness of the theoretical analysis, a vector-control system of thesynchronous reluctance motor considering the magnetic saturation, is then established,using the proposed algorithm in Matlab/Simulink condition. A simulation experimentincluding the comparison of the saturated model and linear one,the stator flux linkageobserver, the vector-control system based on the observer and the MTPA controlstrategy based on variable step searching, is conducted, by means of the establishedsystem. The simulation results show that, the parameters of the synchronous reluctancemotor considering the magnetic saturation varies vividly as the operating conditionchanges, the improved Flux observation result can effectively observe the flux, thevector control system based on the improved flux observer can realize the torque controland MTPA strategy.In order to further verify theoretical analysis, combined with scientific research projects, the controller of SynRM based on TMS320F2812and the software of thecontroller are designed. And then the proposed strategies are verified in the experiment.The results show that, the proposed model considering the saturation and the proposedstrategy based on the model can reflect the effects of saturation of motor parameters, theMTPA can be realized.