Open AccessDOI
Describing function applied to HVDC systems harmonic instability
J. M. Ferreira de Jesus,L.L. Freris,J.P. Sucena Paiva +2 more
- Vol. 134, Iss: 2, pp 131-137
TLDR
In this paper, a detailed computer model for an HVDC link is developed which allows the calculation of both the DC and the AC harmonics in the steady state and the describing function for subharmonics of the firing frequency of the convertor.Abstract:
The adoption of voltage-controlled oscillator based firing systems has almost completely eliminated the harmonic instabilities experienced in early HVDC systems. However, the basic feature of such systems (equidistant firing) is adversely affected by the feedback action of the current control loop, since the direct current may contain uncharacteristic harmonics which are not filtered out by the controller. Under certain circumstances (such as an imbalance and/or a distortion in the alternating voltage, DC-or AC-side resonances near DC or AC harmonic frequencies, respectively) instabilities may occur which are characterised by oscillations synchronised with the alternating voltage, i.e. harmonic instabilities. Nonlinear control-system theory, namely the describing-function method, was used to show that these oscillations are limit cycles whose conditions of occurrence can be predicted. A detailed computer model for an hvdc link was developed which allows the calculation of both the DC and the AC harmonics in the steady state and the describing function for subharmonics of the firing frequency of the convertor. Limit cycles can be predicted by the Nichols chart technique.read more
Citations
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Journal ArticleDOI
Composite resonance; a circuit approach to the waveform distortion dynamics of an HVdc converter
Alan R. Wood,J. Arrillaga +1 more
TL;DR: In this article, a frequency domain analysis is applied to a controlled HVDC power converter interconnecting AC and DC power networks, and the converter is considered as a three-port network, and described using transfer functions.
Journal ArticleDOI
Frequency domain based control design for an HVdc converter connected to a weak ac network
TL;DR: In this paper, a small-signal frequency domain model of an HVDC system connected to a weak AC network is used for an operating point-based rectifier direct current control design.
A harmonic domain model for the interaction of the HVdc convertor with ac and dc systems.
TL;DR: In this paper, a steady state analysis of the HVdc convertor is described, and a robust sparse Newton solution of the converter equations is developed for a variety of unbalanced and resonant test systems, which are validated against time domain simulations.
Proceedings ArticleDOI
Modeling and analysis of DC-link harmonic instability in LCC HVDC systems
Hanchao Liu,Jian Sun +1 more
TL;DR: This paper proposes a different approach using the dc terminal impedance of the HVDC converters to determine the stability of the dc link under various control designs.
Proceedings ArticleDOI
DC terminal impedance modeling of LCC-based HVDC converters
Hanchao Liu,Jian Sun +1 more
TL;DR: Small-signal impedance modeling of line-commutated converters (LCC) for HVDC system stability analysis is presented by using the harmonic linearization method and taking into account the ac grid impedance as well as control of the converter.
References
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Journal ArticleDOI
Stability of rectifiers with voltage-controlled oscillator firing systems
J.P. Sucena-Paiva,L.L. Freris +1 more
TL;DR: In this paper, a linearised discrete model for a rectifier has been used successfully in stability studies of convertors with conventional individual-phase firing systems, and the model is modified to simulate rectifiers incorporating voltage-controlled oscillator firing systems that possess an integral characteristic.
Journal ArticleDOI
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Journal ArticleDOI
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