Sliding Mode Observer For Position Sensorless Control Of Ship Permanent Manget Synchronous Motor

In recent years, the marine electric propulsion system is becoming the major development trend of the dynamic systems in marine engineering, due to the advantages of reducing fuel consumption, improving the ship maneuverability and saving space. Because of the advantages of high efficiency, high power density, and fast dynamic response, the permanent magnet synchronous motors (PMSMs) have been widely applied to the electric compact propulsion systems. Position sensorless control of PMSM has important practical significance in the ship propulsion PMSM driving system, because it can improve the system reliability and reduce the system working conditions requirements. In this dissertation, the rotor position and speed of the ship interior permanent magnet synchronous motor (IPMSM) based on the sliding mode observer (SMO) have been estimated and the sensorless control of the PMSM has been realized. The investigated contents are shown as follows:The ship PMSM variable frequency speed control theory and the propeller load characteristics are analyzed. The mathematical model of ship IPMSM is established and the vector control (VC) and direct torque control (DTC) methods for the PMSM are studied. The propeller load mathematical model established by analyzing the propeller load characteristics and the simulation research implemented combining with the ship experiments data. Then based on the propeller load characteristics, a simulation model established for the ship propulsion PMSM variable frequency and speed control system. According to the propeller load characteristics and ship PMSM operating conditions, a suitable position sensorless control strategy selected for ship PMSM.The estimation method of PMSM rotor position and speed using a novel SMO is researched. Based on the vector control theory, the state equations that using the state variable of dq current in the synchronous rotating frame is established. Meanwhile with the difference between the actual and observer current as the sliding surface, the novel SMO is designed. Using Lyapunov stability theory analysis, the value selection conditions of the switching gains and the feedback gains are analyzed and the calculation expression of the rotor speed is deduced. Meanwhile, by using the method of pole placement in the novel SMO, the parameter values of the feedback gains are selected to guarantee the system stability. Through the theoretical analysis, the simulation model of ship PMSM position sensorless control system that based on the novel SMO has been established. The stability and validity of the designed SMO are verified by simulation results.The study on optimizing performance of SMO is investigated. Aiming at the chattering problem in the observer, by using a sigmoid switching function to replace the switch function and regulating the value of switching gains according to the state of the sliding surface, the chattering problem is reduced with the control strategy that combined with continuous switching function and optimal regulation for the switching gains. Aiming at the problem of observer parameters optimization, particle swarm intelligent optimization algorithm is used, the integral value of producting of speed error absolute value with time is chosen as a performance evaluation function in the algorithm and the four adjustable parameters in the observer have been optimized. The simulation results show that the estimation performance of the modified SMO optimized.The study on low speed starting and running of the ship PMSM is investigated. To solve the problem of detecting the rotor initinal position, the mathematical model of PMSM under rotating high frequency excitation has been established. The estimation error signal is obtained by demodulating and processing the high frequency carrier current that contains the rotor position information. Then effective detection of PMSM rotor initinal position is realized by using rotor position observer that based on the phase locked loop (PLL) technique. Combined with the designed of SMO, the ship PMSM starting at low speed and accelerating running to high speed operation conditions is analyzed and stable operation of the ship PMSM position sensorless control is realized...