Analytical Simulation Of Squirrel Cage Induction Generator-rectifier System Based On SPWM

The induction generator is often used in the full power wind generation system. The simulation of several induction generator-converter systems in large scale wind power generation system takes a long time through practice, because of many converters, symmetrical and asymmetrical motor transients. The limitation of numerical simulation is not conducive to the analysis of large scale wind power generation system. The thesis presents a more rapid analytical simulation method, assuming the DC voltage of Squirrel-cage induction generator-rectifier system is constant. The specific contents are as follows:1. Firstly, mathematical methods for solving transient models of AC motor are summarized, and the features of analytical and numerical methods are compared.2. Secondly, the order and action time of eight switching states of the system are determined according to the relationship between the three-phase modulation and asymmetric regular sampling method. The order and time provide a theoretical basis for the analytical simulation of variable step.3. Thirdly, the mathematical models of the system under different switching states are derived by using of space vector, based on the voltage relationship between the induction generator and rectifier. Further, induction generator stator and rotor current expressions in the time domain can be derived after analytical solution of mathematical model.4. Finally, the eight operation states of the system can be linked perfectly by using the derived system mathematical models. And then the operation behavior of system under a particular condition is calculated analytically. Furthermore, the same operation is simulated by improved Euler method and Runge-Kutta method. Three kinds of simulation methods are programming out with help of M file.Compared with the numerical simulation results and simulation results in Simulink of the system in the same condition, the analytical simulation method consumes less time under the condition of the approximate simulation accuracy. In summary, analytical simulation method can accelerate the simulation speed of the research system.