Predictive Current Control Based On Feedforward Compensation Of Marine Propulsion PMSM

As the modern power electronics technology develops and high-power AC motor speed control technology matures,marine electric propulsion system has become an important part in ship propulsion systems.Meanwhile,permanent magnet synchronous motor(PMSM)has become a significant selection for marine electric propulsion motor due to its advantages in various aspects.As the requirements of the propulsion system for the performance of propulsion motor control become higher,conventional vector control system based on Proportion-Integration control will fail to fulfill this requirement.Model Predictive Control(MPC)has taken the effect of the controlled variables on the future state of the system into consideration and can achieve better control performance.Although MPC has been successfully applied in the field of process control,its application on PMSMs is still not sufficient.Research on predictive current control for PMSM in the field of marine propulsion would effectively improve the control performance of PMSM,which has tremendous engineering value.In this paper,MPC algorithm is applied to PMSM current control.The main contents are as follows.1.In this paper,the structure of PMSM in marine propulsion system and its mathematical model have been analyzed.Based on the study on propeller load characteristics and ship motion model,by referring to the vector control,coordinate transformation and space vector pulse width modulation technology,simulation model of control system for marine propulsion PMSM with load on propeller has been established.2.By analyzing the basic principles and characteristics of model MPC,a predictive current controller for permanent magnet synchronous propulsion motor has been designed exploiting the voltage decoupling method.With reference to uncertainties of the parameters perturbation and unmodeled dynamics in PMSM,a disturbance observer is designed to estimate the disturbance voltage and offset the voltage disturbances through the voltage feedforward compensation.As a result,more accurate current control has been achieved and is verified by simulation.3.A discrete sliding mode controller based on saturation function and a disturbance observer is designed to regulate motor rotation speed and estimate external disturbances.Thus load torque current feed-forward compensation is achieved and the performance of marine electric propulsion system is improved against wind,wave and drift disturbance.In this paper,an effective predictive current control scheme based on both disturbance voltage feedforward compensation and load current feedforward compensation has been proposed.The accuracy of current control has been further improved,and simulation demonstrates the effectiveness of the proposed control scheme in marine propulsion PMSM control system.