Research On Electric Propulsion Load Simulation System

Marine electric propulsion is one of the most important application fields of electric drive and widely used, its simulation system plays a so important role, for it can reduce the cost and risk during R & D and system test time. Based on overall review of previous work, this paper deeply researches domestic need of the key projects and experiments for transportation, and introduces a novel high performance and energy-save programme, the system mathematic modeling, digital simulation and stability analysis are studied in detail, and gets the following achievements.The dissertation deeply analyzes the simulation theory and its dynamic regulation procedure. In order to realize the ship-propeller model(SPM) and design the complete simulation system hardware, a method combined MATALB real time simulation tool RTW and data acquisition card(DAC) PCI-1711 for outer load torque control has been introduced, which makes the SPM much more conveniently and efficiency.Based on simple switching function(SF), this paper models the whole simulation system for the first time, including the stationary and synchronous rotating frame models, and the control strategies are further studied. Variable step and simplify method are used for the whole system simulation, to reduce the simulation time consumption, but without any loss of simulation precise.This paper describes the parameter sensitivity of electric torque and rotor flux linkage decoupling control in the torque producing step of indirect vector control, the mathematical expression is deduced and some useful results are achieved, and the regulation principle is summarized by using MATLAB tools.For the pure time delay from SPM to simulation converter will affect the stability of simulation motor, even propulsion system, this paper modifies the close loop gain to compensate the time delay affection, through the analysis from Bode or Nichols curves. Simulation result indicates its ideal control effect.In order to study the whole system stability when system parameters changes, based on small signal disturbance theory, the dissertation uses partial differentiation to linear the simulation system's state space model, and then the first Lyapunov theory is used to analyze the stability. The large signal stability is also used to describe the inherent nonlinear stability problem, and some methods to increase the stability are given, which completes the simulation system stability analysis.The simulation system designed by this paper, and these research results have so strong generality that can also be used for other transportation and industrial AC drive systems research, such as mainline railway, urban rail transit, mine lifting apparatus, steel rolling, etc..