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VSC-HVDC system robust stability analysis based on a modified mixed small gain and passivity theorem

Yujiao Song (Institutionen för signaler och system, Reglerteknik) ; Claes Breitholtz (Institutionen för signaler och system, Reglerteknik)
20th IFAC World Congress on International Federation of Automatic Control (2017)
[Konferensbidrag, refereegranskat]

In a VSC-HVDC system, when the input power to the converter is controlled to a positive constant, the converter acts a differential negative resistance −P0/i0^2, which may cause instability in case of a connected weak AC-grid. In order to analyze the robust stability of such a system, a modified mixed small gain and passivity theorem is proposed, which shows that the negative feedback interconnection of two linear time invariant stable subsystems (converter admittance and AC-grid impedance) is input to output stable if in certain frequency bands, both subsystems are passive and at least one of them is strictly passive; at the remaining frequency bands, the loop gain is to be strictly less than one. Under different AC-grid topologies, the stability sufficient conditions with respect to the AC-grid inductance are studied. It shows that for AC-grid consists of series RgLg-circuit, an introduced series capacitor can improve the system robustness but not for the shunt capacitor.

Nyckelord: Robust stability of LTI systems, passivity, small gain, VSC-HVDC system, AC-grid interaction, linearized model

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Denna post skapades 2017-03-01.
CPL Pubid: 248331


Institutioner (Chalmers)

Institutionen för signaler och system, Reglerteknik (2005-2017)



Chalmers infrastruktur