Simulation Research And Design For The Three-Phase Voltage Sag Simulator

As we know, many power quality problems are caused by the voltage sags. Three-phase voltage sag simulator is used as a tool to evaluate the effects of momentary voltage sag and voltage short interruptions on industrial load. This paper systematically studies the method for the realization of the three-phase voltage sag simulator,designs the three-phase voltage sag simulator by using Back to Back voltage source PWM converter topology structure; Based on the dq0 coordinates, this paper proposes the formation methods which are related to the voltage sag type,sag amplitude and duration, also the realization methods of accurately producing three-phase symmetrical and asymmetrical voltage sag are presented. By using the Matlab/Simulink, this paper reproduces the simulation of the sag depth and duration which contains the typical voltage sags seven types A, B, C, D, E, F, G. By analyzing the FFT spectrum of FSC maximum phase voltage sag, it can be seen that the total harmonic content is very low, the voltage waveform is closed to the standard sine wave. Meanwhile, the current and voltage of the GSC have the same phase,Power factor is over 0.99,AC current of the THD is controlled less than 5%,In this way,all possible three-phase system voltage sag events can be simulated comprehensively and realistically, so it is verified that the implementation method and the designed circuit is correctness and feasibility. Simulation results also show that the three-phase voltage sag simulator can be used to evaluate the effects of momentary voltage sag and short interruptions not only on industrial passive load, but also on industrial active load.