An Improved Impedance Measurement Method Based on Multi-Sine Signal Considering the Suppression of Noise Interference

Impedance measurement is a practical method to obtain the impedance characteristic of power electronic equipment (PEE), which important for small-signal stability analysis. In measurement, results may be influenced by external noise. Therefore, it essential study how avoid errors caused To address this issue, paper analyzes suppressing noise interference enhancing signal-to-noise ratio (SNR) and concludes that there limitation on improving accuracy merely SNR due perturbation amplitudes. And then proposes an improved method, can decreased effectively. By investigating influence mechanism results, error divided into average component fluctuant component. The eliminated averaging two groups with phase difference π rad while minimized employing complex-linear fitting algorithm. Finally, experiments are conducted verify effectiveness proposed method.