TechRxiv
main.pdf (7.61 MB)
Download file

Accurate High Frequency Modelling of the Input Admittance of PWM Grid-Connected VSCs

Download (7.61 MB)
preprint
posted on 22.02.2022, 03:54 authored by Ruzica CvetanovicRuzica Cvetanovic, Ivan Petric, Paolo Mattavelli, Simone Buso
This paper addresses high frequency admittance modelling of current-controlled voltage source converters (VSCs). Recent studies have shown that harmonic instability may also occur at frequencies above the Nyquist frequency. To form an accurate multiple-frequency model in this frequency range, sidebands that originate from modulation and sampling must be examined. In this paper, an accurate small-signal model is developed taking into account an adequate digital pulse-width modulator (DPWM) representation, which allows to predict dependence of the frequency response on the steady-state DC (SSDC) operating point. It is shown that, when center-pulse sampling is implemented, PWM sidebands do not create additional loops leaving only sampling sidebands to be considered. Using the same approach as for SS-DC operation, a model which accurately represents admittance measurements during sinusoidal AC (S-AC) operation is developed. Its basis is a novel DPWM model suitable for S-AC regime, which allows to predict dependence of the VSC’s input admittance on the grid voltage magnitude. Experimental and simulated admittance measurements, performed on a single-phase two-level VSC during various SS-DC and S-AC regimes, show an excellent match with the proposed models up to twice the sampling frequency

History

Email Address of Submitting Author

ruzica.cvetanovic@phd.unipd.it

ORCID of Submitting Author

0000-0001-9713-2656

Submitting Author's Institution

University of Padova

Submitting Author's Country

Italy