The Research Of Control System Of Synchronous Motors Applied In Ship Electric Propulsion

In recent decades, with the rapid development of power electronic devices and high-power converters, ship electric propulsion is becoming the main direction of future ships with several advantages such as higher flexibility of space allocation, better maneuverability, higher efficiency. Ship electric propulsion system's robustness and controllability is closely related with the promotion of motor control. As the propulsion motor system affected by the external load disturbance, object modeling inadequate and non-linear dynamics uncertainties, advanced control strategies must be studied to obtain high-performance speed control system.The research background in this paper was based on one electric ship. More in-depth theoretical analysis and simulation study were conducted in order to cope with problems in the propulsion system such as load disturbance, object modeling inadequate . Main research contents were summarized as follows:1. Based on the certain electric ship,the characteristics of thrust force and torque were analyzed as well as the interaction between propeller and paddle. According to the electric propulsion ship-related parameters and calculated ship resistance, the major equipment of propulsion systems such as propulsion motors, inverter were selected. A six-phase synchronous motor was chosen as the driving motor of the system because of its excellent performance in variable speed of high power system.2. Mathematical models of a six-phase synchronous motor in different coordinate systems were analyzed here, as well as the basic principle and the implement method of vector control. In accordance with the characteristics of elected six-phase synchronous propulsion motor and electric propulsion requirements, the control system based on air-gap-field orientation vector control is adopted. The mathematical models of every stage in the vector control were built. 3. On the base of the vector control strategy and mathematic model of 6-phase synchronous motor system, the simulation model is established and the parameters of current controllers, speed regulator, gas-flux regulator and excitation current regulator are designed respectively. Since the contradiction between stability and accuracy which can't be solved by conventional PID control system, in order to improve the anti-jamming capability and robustness of the system, single neuron adaptive PID controller based on quadratic performance index learning algorithm was designed.4. The system model was established in MATLAB/Simulink environment. The results of the simulation indicate that the single neuron adaptive PID controller has a simple structure, strong self-learning and adaptive ability of the characteristics and the control performance is superior to the traditional PID control. The anti-jamming capability and robustness of the system is improved observably.