| With the progress of the times and technology,the control performance of the AC speed regulation system has been continuously improved.Permanent magnet synchronous motor(PMSM)is more and more widely used because of its advantages of high power density,large torque inertia and fast dynamic response.However,the existence of traditional position sensors has brought many problems,such as installation difficulties,increased driving costs,strict use environment requirements,and reduced estimation accuracy caused by interference.In order to avoid these problems,scholars and experts began to study a type of sensorless Control Method.Due to the limitations of some relatively mature control algorithms,they can not achieve stable control in a complete speed range,whether it is the high-frequency signal injection method for low-speed section or the back EMF observation method for high-speed section.Therefore,this paper selected Built-in Permanent Magnet Synchronous Motor(IPMSM)to combine the two types of control algorithms to achieve stable on-load control of the motor in the full speed range.First,this paper analyzed the current research status of permanent magnet synchronous motors,and showed the limitations of single control algorithm,so as to illustrate the research value and significance of composite control algorithm.After that,starting from the basic structure of PMSM,the mathematical model of IPMSM and the transformation of the three coordinate systems were analyzed and derived in detail.Based on a brief introduction of the basic principles of the high-frequency injection method and the carrier signal selection method,the mathematical model of the rotating high-frequency injection method was established in three different coordinate systems,and the simulation model was built.Through simulation analysis,its control effect was verified.As the speed increases,the angular frequency effect of the voltage injected by the rotating high-frequency injection method becomes more serious.In view of this defect,the Extended Kalman Filter(EKF)was selected in the high-speed section.The development history and basic principles of EKF were summarized,and a state observer was designed.At the same time,the influence of relevant parameters on its estimation accuracy is analyzed,and on this basis,a simulation model based on EKF was established,and its control effect was verified through analysis of simulation results.After designing the control algorithms for two different speed domains respectively,this paper mainly studies how to realize the smooth and stable transition between them.Firstly,the two transition schemes that are currently in use are analyzed and compared,and the direct transition method was selected after weighing their advantages and disadvantages.After theoretical analysis,first determine the switching position within 500-700r/min through simulation experiments,and then through more detailed debugging,used the trial and error method to determine the specific position of the switching point.After the no-load experiment was completed,a propeller load was introduced into the control system.Firstly,some basic characteristics of propeller load were analyzed.Considering that the propeller and ship should be integrated,several interactions between the propellers were introduced.Finally,a propeller load simulation model was built to achieve stable control of the propeller.Finally,based on the above research and analysis,the propeller load was combined with the full speed domain control algorithm to build a complete IPMSM control system simulation model.The simulation results showed that the system can track the rotor status information more accurately and quickly,the estimation error was small,and the ship’s speed was stable,and the whole can meet the system design requirements. |
