Research Of PMSM Model Predictive Control For Ship Electric Propulsion

With the rapid development of power electronics,motor control technology and modern control theory,ship electrical propulsion technology is widely applied.With the advantages of high power factor,good safety performance and low energy consumption,permanent magnet synchronous motor(PMSM)is the best choice of propulsion motor in the ship electrical propulsion system.Therefore it has practical significance to develop the research of PMSM control system for the design and application of ship electrical propulsion system.The dynamic mathematical model of PMSM in rotating coordinate is established based on the coordinate transformation,and simulation of vector control is researched via space vector pulse width modulation.On the basis,the PMSM model predictive control is investigated in this thesis.The study has achieved the following tasks:1.With respect to the uncertainties included in the PMSM which is difficult to be controlled by traditional linear rotation speed controller for its strongly coupled nonlinearity,a new linear system is derived from decoupling the nonlinear PMSM model through input-output feedback linearization,and speed tracking control is achieved by a model predictive controller based on standard model predictive control(MPC)strategy.2.In order to solve the input voltage saturation,a PMSM model predictive controller with input constraints is designed using variable constraint technique,which effectively limits the damage against motor because of the over-high control input voltage.3.Usually,the load disturbance is the main reason that results in rotation speed perturbation in PMSM control system.While the load disturbance can hardly be measured directly,PMSM model predictive controller is designed in the view of disturbance observer in this thesis and the unknown external disturbances is estimated via disturbance observer,that the real-time compensation will be realized on-line in the control system.Furthermore,a comparison between this method and nonlinear predictive control method widely applied to PMSM recently is put forward,and the simulation results show that the method designed in this paper has better robustness and rotation speed tracking characteristic.4.Finally,the ship electric propulsion control system model is constructed based on the combination of PMSM control system,ship motion and propeller characteristics.Simulation of ship sailing and propeller inhead sea test are carried out referring to the parameters of a marine vessel.The simulation results demonstrate that MPC technique has excellent speed controlling performance and can satisfy the demands of the integral ship electric propulsion control system.