Total-Amount Coordinated Control Of Multi-Motors With Saturation Constrains

With the deepening of the“Belt and Road”construction and the national economic development,China has adjusted its transport structure and increased the volume of railway transportation.As an important part of railway freight industry,heavy-haul trains need to study the key technology of the total-amount coordinated control of multiple traction motors to improve the transportation capacity and ensure the overall traction performance and stable operation in the complex and changeable environment.In the multi axis coordinated control of locomotive,the total traction force provided by each motor is not changed by coordinating traction torque output redundancy of other traction motors.However,in the existing multi-motor total-amount coordinated control technology,the saturation constraint(input saturation,output constraint,etc.)is not considered.Therefore,this thesis focuses on the research of multi-motor total-amount coordinated control and its practical application under saturation constraints.Specific research contents are given as follows:1.For the multi-motor total-amount coordinated control system with input saturation,considering the control parameter reduction and the anti-windup(AW)compensation,a total-amount coordinated tracking AW sliding-mode(SM)control strategy is designed.First,a multimotor traction model with uncertain parameter perturbations and external disturbances was established.Next,a SM disturbance observer was designed to reduce the SM switching gain,thereby decreasing the control input.An auxiliary AW system was used to weaken the effect of saturation on tracking performance,thus compensating input saturation.Then,the observed value and the auxiliary state were fed back to the SM controller to design a total-amount coordinated control algorithm and ensure that the total amount of traction torque follows the desired traction characteristic curve.Finally,the excellent performance of the SM observer and the controller was verified by the Matlab/Simulink numerical simulation and RT-Lab semi-physical experiment,which shows that the control strategy can suppress input saturation effect in the multi-motor traction system effectively.2.For the multi-motor total-amount coordinated finite-time control system with input saturation,considering the parameter simplification of“adding a power integrator”(AAPI)and the AW technology,a total-amount coordinated tracking control strategy based on nonsingular terminal SM is designed to ensure the global finite-time stability.First,based on the d-q coordinate system,a multi-PMSM _di(28)0 vector control model with uncertain parameter perturbations and external disturbances was established.Next,a finite-time auxiliary AW system was designed and the auxiliary state was fed back to total-amount coordinated tracking controller.Then,the strong constraint of parameters of AAPI was relaxed,the setting rules of the corresponding parameters were given and the proof of finite-time Lyapunov stability was completed.Finally,the excellent performance of parameter simplification and the controller was verified by the Matlab/Simulink numerical simulation and RT-Lab semi-physical experiment,which shows that the control strategy can suppress input saturation effect in the multi-motor traction system effectively.3.For the multi-motor total-amount coordinated control system with input and output saturation,a hierarchical total-amount coordinated AW framework is constructed,and a saturated super-twisting SM control algorithm combined with the multi-motor total-amount optimal cooperation is designed.First,based on the x-y coordinate system,the model of the direct torque control of multi-PMSM was established.Next,considering the total-amount of output torque consistency and constraints,the optimal multi axis total-amount coordinate allocation given algorithm was designed based on KKT(Karush-Kuhn-Tucker)conditions with the minimum energy consumption as the goal.Then,according to the optimal allocation given,a new saturated super-twisting SM control algorithm was designed,and combine the barrier Lyapunov function to prove that the control input is bounded.Finally,the excellent performance of the optimal allocation given algorithm and the controller was verified by the Matlab/Simulink numerical simulation and RT-Lab semi-physical experiment,which shows that the control strategy can solve input and output saturation problem in the multi-motor traction system effectively.