Fast-Slow-Scale Interaction Induced Parallel Resonance and its Suppression in Voltage Source Converters

Multi-timescale interaction of power electronics devices, including voltage source converter (VSC), has made the stability and analysis high penetrating renewable systems very complicated. In this paper, impedance model is used to analyze multi-timescale characteristics VSC. Firstly, VSC are investigated based on Bode plots. It found that slow-timescale (within DC-link control scale) fast-timescale AC current models separately consistent with full-order perfectly within their low- high-frequency ranges. addition, there exists a peak intermediate frequency range (roughly from 10 Hz 100 Hz). Then, theoretically estimated explained by slow-fast-scale parallel resonance through transfer-function diagram analysis. Moreover, it more related some outer controllers, such as alternative active control. Specifically, larger proportional coefficients can greatly suppress peak. Finally, simulations experiments conducted verify generality Hence these findings not only significant provide physical insight into inner key structure VSC, but also expected be helpful for controller parameter design