Stability Analysis of High-Frequency Interactions Between a Converter and HVDC Grid Resonances

Lekić, Aleksandra; Alam, Mohammad Meraj; Beerten, Jef

doi:10.1109/tpwrd.2020.3041176

Cited by 23 publications

(12 citation statements)

References 35 publications

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“…This result is not reported in the paper. What we found is that there is not any negative impedance effect at high frequencies (some kHz) as described in [36], at least for our design. From our standpoint this is an expected result, since the signals driving the MMC are low-pass filtered (these filters are not shown in Fig.…”

Section: Stability Analysis Through Vector Fittingsupporting

confidence: 59%

“…To force its usage, the model must be deeply simplified in order to obtain a solution represented by a simple equilibrium point in the dq0frame. This is what is done in several papers (see for example [36]) but requires a significant amount of effort that can be avoided by applying our proposed method. As anticipated in the Introduction, a good numerical tool able to compute the impedances of the MMC model without resorting to any simplification is the PAC method, which we present in the next section.…”

Section: Frequency Scanmentioning

confidence: 61%

“…To showcase this feature, we considered once again the DCS1 system and investigated as an example the possible instability triggered by the insertion of inductor-based Fault Current Limiters (FCLs) at each pole of the DC side of MMC1. This issue has been recently reported for instance in [36], [53], [54], where the authors showed that a too large inductance leads to instabilities [53], [54]. In [36] the authors came to the opposite conclusion (i.e., a too small inductance value leads to instabilities).…”

Section: Stability Analysis Through Vector Fittingmentioning

confidence: 82%

“…This issue has been recently reported for instance in [36], [53], [54], where the authors showed that a too large inductance leads to instabilities [53], [54]. In [36] the authors came to the opposite conclusion (i.e., a too small inductance value leads to instabilities). It thus seems that an interval of inductance values exists in which the insertion of a reactor limits the DC short circuit current, and does not trigger instability phenomena.…”

Section: Stability Analysis Through Vector Fittingmentioning

confidence: 82%

See 3 more Smart Citations

Modular Multilevel Converter Impedance Computation Based on Periodic Small-Signal Analysis and Vector Fitting

Giudice

Brambilla

Linaro

et al. 2022

IEEE Trans. Circuits Syst. I

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Instability and oscillation issues originating in highvoltage direct current (HVDC) systems comprising modular multilevel converters (MMCs) are gaining increasing interest in the research community. To detect such phenomena in advance, considerable effort has been devoted recently to developing MMC models for small-signal analysis. The derivation of such models is a challenging task due to the topology and complex control structure of MMCs, which results in them having a multi-frequency response. To address this issue, scholars developed methods based on dynamic phasors and harmonic state-space modelling, which, however, require extensive pen-and-paper computations. In this paper, the periodic small-signal analysis (PAC) is adopted to determine numerically several MMCs transfer functions. Such functions can be computed between any electrical circuit node or input/output port, without the need to recast the three-phase average MMC model to derive a linear equivalent one, possibly in the DQ-frame. We show how vector fitting allows converting these functions to equivalent algebraic representations, which can be profitably used to design MMCs and study their stability following some parameter changes. To showcase this feature, we exploit one of these transfer functions to detect DC-side instability in a point-to-point HVDC system.

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Section: Stability Analysis Through Vector Fittingsupporting

confidence: 59%

Section: Frequency Scanmentioning

confidence: 61%

Section: Stability Analysis Through Vector Fittingmentioning

confidence: 82%

Section: Stability Analysis Through Vector Fittingmentioning

confidence: 82%

See 2 more Smart Citations

Modular Multilevel Converter Impedance Computation Based on Periodic Small-Signal Analysis and Vector Fitting

Giudice

Brambilla

Linaro

et al. 2022

IEEE Trans. Circuits Syst. I

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“…In the literature, the time-periodic behavior of the MMC has at times been disregarded or simplified by neglecting part of internal converter dynamics [6], [7]. However, such simplifications result in models of limited accuracy from low to intermediate frequencies [8]. The periodicity can be taken into account, for instance by transforming the dynamic equations into formulations that are linear time-invariant (LTI) in steady-state, so that traditional LTI stability analysis techniques can be applied.…”

Section: Introductionmentioning

confidence: 99%

Generalization of Harmonic State-Space Framework to Delayed Periodic Systems for Stability Analysis of the Modular Multilevel Converter

Rua

Beerten

2022

IEEE Trans. Power Delivery

Self Cite

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Stability analysis of the modular multilevel converter (MMC) requires accurate models over wide frequency ranges, accounting for both the time-periodic nature of internal dynamics and non-passive behavior resulting from time delays. Frequency-lifting techniques such as harmonic state-space (HSS) can be used to tackle the time-periodicity and obtain linear time-invariant models on which classical stability analysis techniques can be applied. However, exact time delays are generally approximated by rational polynomial functions to study the eigenvalues of ordinary differential equations (ODEs), which leads to inaccuracies at higher frequencies. Such approximations can be avoided by preserving delays in their exact form and studying eigenvalues of delay differential equations (DDEs).To that end, this paper presents the generalization of the original ODE-based HSS framework to DDEs, accounting for both time-delay and time-periodic behaviors of the MMC. The generalized HSS framework benefits from the insights of eigenvalues and participation factors analysis while at the same time guaranteeing the derivation of accurate frequency-response models. Using the developed HSS-DDE framework, AC and DCside admittances of the MMC are obtained and validated against frequency scans. Lastly, the stability of a test system is studied in both time and frequency domains to show the advantages of the developed framework.

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Introduction

Chen

2024

Springer Theses

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Stability Analysis of High-Frequency Interactions Between a Converter and HVDC Grid Resonances

Cited by 23 publications

References 35 publications

Modular Multilevel Converter Impedance Computation Based on Periodic Small-Signal Analysis and Vector Fitting

Modular Multilevel Converter Impedance Computation Based on Periodic Small-Signal Analysis and Vector Fitting

Generalization of Harmonic State-Space Framework to Delayed Periodic Systems for Stability Analysis of the Modular Multilevel Converter

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