This paper presents a systematic evaluation on the impedance passivity of voltage-controlled voltage-source converters. The commonly used single- and dual-loop control structures with different linear controllers are compared extensively, considering the effect of the time delay involved in the control loop. A virtual impedance control, co-designed with different voltage control schemes, is then proposed to eliminate the negative output resistance till half of the sampling frequency, which improves the system stability for grid-forming converters in grid-connected applications. Both frequency-domain analysis and experimental results validate the theoretical findings.
|Journal||I E E E Open Journal of the Industrial Electronics Society|
|Number of pages||14|
|Publication status||Published - Jun 2020|
- voltage-source converter
- voltage control
- harmonic stability
- impedance analysis