The Optimization Analysis of Impulse Injection Method for Impedance Measurement in Three-Phase Power Electronic Systems

Due to the high frequency nature and constant power load characteristics, stability issue exists widely in contemporary power electronic systems. Impedance-based criteria can be used in stability prediction. Thus, the accurate extraction of impedance becomes significantly important. For AC systems, impulse injection method has been proposed for its short measurement duration, but the accuracy needs to be improved. This paper introduces the optimization analysis of impulse injection method for impedance measurement in three-phase power electronic systems, which aims at finding the optimization impulse injection waveform in time domain to enhance the accuracy. By comparing the frequency spectrum of basic impulses, this paper proves that injecting bipolar square wave at zerocrossing point shows the best efficiency. Simulation verifies the analysis.