| With the continuous advancement of industrial automation technology,because the traditional industry relies on a single motor to achieve industrial control through mechanical shaft transmission,it has been unable to meet the requirements of current industrial production,and therefore,it has gradually been replaced by multi-motor synchronous control.In the multi-motor synchronous control system,the non-coupling synchronous control has less controllability and has no physical quantity such as material properties and mechanical friction,and has the advantages of simple control and high control precision,but the motor that can be controlled The number is small and cannot meet the needs of industrial automation development.For the coupled synchronous control system,taking the most commonly used deviation coupling control structure as an example,the structure has good coupling,and the number of motors that can be synchronously controlled is large,but the control is complicated and the control precision is not high.Therefore,it is particularly important to find a multi-PMSM synchronization control strategy that can balance the control volume,control motor quantity and control accuracy relatively high.This is the research focus of this paper.In the multi-motor synchronous control system,the traditional deviation coupling structure has complex mathematical model of the speed compensator,large on-line calculation,and tracking error and synchronization of each motor when the system load is unevenly started and the load is suddenly disturbed during stable operation.The error is very large.Aiming at the shortcomings of traditional deviation coupling structure,such as poor tracking performance,poor synchronization performance and complex mathematical model of speed compensator,this paper designs an improved multi-motor deviation coupling synchronous control structure with virtual motor.Structurally,this improved structure introduces the concept of a virtual motor.Each motor follows the trajectory of the virtual motor during system operation,which can reduce the synchronization error very well.In addition,the improved structure applies the output speed of each motor to the virtual motor,and there is no direct coupling relationship between the motors,and then each motor is synchronously controlled by the virtual motor.Because the speed difference involved in each speed compensator of the improved structure is small,the model of the speed compensator is relatively simple.In terms of performance,the improved structure can reduce the tracking error and synchronization error caused by the load disturbance of the motor to some extent.In order to improve the control precision of the system,enhance the robustness of thesystem,and solve the problem of poor reliability of conventional hard sensors,this chapter designs a back-step terminal sliding mode controller without speed sensor to replace the traditional PI controller.By replacing the speed sensor with a speed sensor,it can more effectively estimate the real-time speed of the motor and improve the accuracy of the system control.Finally,the experiment was carried out by setting up the experimental platform,and the performance comparison analysis was carried out on the traditional partial difference structure and the improved deviation coupling structure.It can be seen from the analysis of the experimental results that under the same conditions,the synchronization error of the improved structure is small when the system motor load is unevenly started.When the system is suddenly disturbed by the load during the stable operation of the system,the system synchronization error of the improved structure is also obvious.Less than the traditional structure.At the same time,the experimental results show that the synchronization performance and starting speed of the improved structure are affected by the moment of inertia of the virtual motor.Therefore,the size should be reasonably selected in the actual control.The thesis has 54 diagrams,7 tables and 63 references. |
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