Permanent Magnet Synchronous Motor Drive And Control System With Load State Observer

Permanent magnet synchronous motor is applied more and more widely in industrial control field because of its lots of advantages such as small in size,high power density,high efficiency,low speed performance and so on.However,the change of load state will influence control performance of PMSM.For example,the variable inertia will worsen the dynamic response of PMSM control system,and load’s fluctuation can bring huge disturbance to rotate speed.Aim at above problems,a kind of load state observer which can observe load’s inertia and torque was studied in the article.The observed result was used to adjust parameters of the control system and compensate the current loop.By this mean the dynamic response and the robustness of the control system would be enhanced.The structure of PMSM was analyzed,the mathematical model of PMSM in the rotating coordinate system was built,vector control and maximum torque per ample control were inferred in the paper.In order to identify the inertia,two kinds of identification algorithm were adopted.On the one hand forgetting factor was introduced into recursive least square and based on forgetting factor recursive least square the inertia was identified.On the other hand,after building reference model and adjustable model,based on Landau discrete recursive identification algorithm,the inertia was identified by model reference adaptable system.Finally,inertia identification was assembled into PMSM control system and speed PI parameters were adjusted according to the identified result.The simulation results indicated that the identification algorithms could identify the inertia fast and precisely also the dynamic property of PMSM control system was improved enormously.To observe load torque,the system that would be observed was built and its observability was verified.And based on Luenberger observer algorithm PMSM Luenberger load torque observer was designed.Then the observer was applied into PMSM control system and current loop was compensated by the observed load torque.The simulation result proved that the load torque was observed by the Luenberger load torque observer effectively and the robustness of PMSM control system was enhanced.After the simulation to above algorithms,the PMSM hardware experimental platform based on TMS320F28335 was built.Some critical circuit and flow of control software was introduced in the article.In the end the algorithms all above were certified to be effective by experiments.