Research On Sliding Mode Speed Control Of Five-phsae Permanent Magnet Tubular Linear Motor

The vehicle suspension is one of the key components which affect the stability and the ride comfort.The stiffness and the damping of the traditional passive suspension cannot be adjusted on-line,hence it can not meet the complicated and changeable road conditions.The electromagnetic suspension can satisfy the different road and driving conditions,hence it can effectively restrain the impact from road and improve the stability of vehicle.The motor is very important to the electromagnetic suspension,which can directly determine the performance of the electromagnetic suspension.Due to the high efficiency and big thrust density,the five-phase permanent magnet tubular linear motor(PMTLM)has become one of the research hotspots for the electromagnetic suspension.Due to the complicated working conditions of the electromagnetic suspension,a lot of uncertain disturbances,especially the mismatched disturbances bring greater difficulties to the motor control system.The mismatched disturbance means the system control signals and the disturbance signals work in different channels.Moreover,five-phase PMTLM is a nonlinear system with multiple variables,strong coupling and uncertainty parameters.Therefore,in order to improve the speed performance of five-phase PMTLM control system under the mismatched disturbances,this paper proposes a sliding mode speed control based on mismatched disturbance observer(MDO-SMC)strategy and a sliding mode speed control based on internal model(IM-SMC)strategy.The simulation and experiment results verify the effectiveness of the proposed strategies.The research content of this paper can be summarized as follows:(1)The characteristics of five-phase PMTLM were summarized.Then,the mathematical model was established under five-phase natural coordinate system and two-phase rotating coordinate system.On the basis,the vector control system of the five-phase PMTLM was built.(2)The principle of sliding mode control was introduced.And then the MDO-SMC strategy was proposed.It introduces a mismatched disturbance observer into the sliding mode surface to ensure that the five-phase PMTLM system is robust to the mismatched disturbances and the matched disturbances.The q-axis current is integrated into the speed controller to realize the dual control of the speed and the current,which can make the motor speed be quickly followed the reference without overshoot.Finally,the effectiveness of the proposed control strategy was verified by the simulated results.(3)Based on the MDO-SMC strategy,the IM-SMC strategy was proposed.The five-phase TPMLM control system is transformed into a first-order inertial system by the internal model controller.The coefficient of internal model controller is used to control the response speed,which can make the motor speed be quickly followed the reference without overshort,and the design of dynamic performance become simplier.Finally,the effectiveness of the proposed control strategy was verified by the simulated results.(4)Based on digital signal processor(TMS320F2812),the platform of five-phase PMTLM system was built.And then the experiments of MDO-SMC strategy and IM-SMC strategy were completed,respectively.Then the effectiveness of the proposed control strategies was verified by the experiment results.