Performance of a DC/AC/DC VSC System to Interconnect HVDC Systems

Luth, Thomas; Merlin, Michaël M. C.; Green, Tim; Barker, Carl; Hassan, Fainan; Critchley, Roger; Crookes, R.W.; Dyke, Kevin J.

doi:10.1049/cp.2012.1971

Cited by 22 publications

(8 citation statements)

References 5 publications

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“…Each MMC phase is divided in two arms, the upper and the lower. Each arm is composed by N submodules (hundreds in HVDC applications) which usually could have two different forms (see [10]): the half bridge, constituted by two switches (IGBT and diode), or the full bridge, formed by four switches as shows the figure 1. The use of full bridges is specially interesting when a fault appears, because controlling them, we can impose the appropriate polarity of voltage during fault events in order to block the fault current [12].…”

Section: Dc/dc Multi-terminal Converter Based On MMCmentioning

confidence: 99%

“…And finally, matrix Γ 22 ∈ R k(3n−1)×k(3n−1) is equal to −Λ 22 by changing only the coefficients of the inductances by the respective resistances. As matrix Λ is invertible, then is possible to write the system (4) in the following classic form: (10) At this point, it is important to realize that the system is not linear, since the input u is multiplied by the state x, but if we apply the theory of switching systems [14], we can transform the same problem in another which will be composed of a finite number of linear systems, as many as possible combinations between the control variables could appear. From equation 10, we can note as all of these possible linear system, which appear variating the input u, have always the same equilibrium point.…”

Section: Dc/dc Multi-terminal Converter Model Based On MMCmentioning

confidence: 99%

“…Nevertheless, and although it has optimal performances and advantages over other topologies,it uses an internal transformer at high frequency [9], which increases significantly the cost of this device. Other authors suggest to link two MMC by the alternative side in order to connect two networks with different DC voltages, as proposed [10]. This structure provides the advantage that the internal transformer is avoided, and also it offers all the advantages given by the use of MMC technology explained above.…”

Section: Introductionmentioning

confidence: 99%

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Stability of DC/DC three terminals converter using Modular Multilevel Converters for HVDC systems

Carrizosa

Bergna-Diaz

Arzandé

et al. 2015

2015 17th European Conference on Power Electronics and Applications (EPE'15 ECCE-Europe)

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This paper presents the modelling and control of a DC/DC bidirectional converter with 3 terminals based on Modular Multilevel Converter (MMC) suitable for high voltage and power applications in multi-terminals high voltage direct current (MT-HVDC) grids. A proof is given in order to guarantee the global stability of the system by means of Lyapunov theory and switching control theory. In addition, a study on how to improve the generated harmonics is shown.

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Section: Dc/dc Multi-terminal Converter Based On MMCmentioning

confidence: 99%

Section: Dc/dc Multi-terminal Converter Model Based On MMCmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Stability of DC/DC three terminals converter using Modular Multilevel Converters for HVDC systems

Carrizosa

Bergna-Diaz

Arzandé

et al. 2015

2015 17th European Conference on Power Electronics and Applications (EPE'15 ECCE-Europe)

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“…In general, DC-DC MMC can be classified into non-isolation [13][14][15][16][17][18][19][20] and isolation version [21][22][23][24][25][26][27][28][29][30][31][32]. Non-isolation ones are usually benefited for reduced investment costs.…”

Section: Introductionmentioning

confidence: 99%

Design and implementation of the low computational burden phase‐shifted modulation for DC–DC modular multilevel converter

Chen

Cui

Wang

et al. 2016

IET Power Electronics

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DC-DC modular multilevel converter (DC-DC MMC) with the medium-frequency or high-frequency interlinked transformer is an attractive candidate for high-voltage-direct-current system and DC grid. This study proposes the phase-shifted modulation for DC-DC MMC, aiming to reduce the switching losses, minimise the computational burdens and obtain the satisfactory performance. According to the features of DC-DC MMC, the least but necessary control parameters are extracted, and their control cycles are also properly designed to adapt to the digital implementation. Then, the modulation algorithm is designed and the parameter mapping is realised by the simplest algorithm. Finally, the voltage fluctuations of the submodules (SMs) under such a modulation are predicted off-line, and the adapted sortand-selection strategy is designed for voltage balance of the SMs. With the proposed modulation, the switching frequencies of all SMs are strictly equivalent to the fundamental frequency; the sampling, parameter mapping and sortand-selection frequencies are also the fundamental frequency. These features alleviate not only the switching loss in the power stage, but also the computational burden in the modulation and control systems. The analysis and design of the proposed modulation will be given in this study, and verified by the experiments.

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“…Investigations into alternative topologies combining series connected semiconductor "director valves" with chains of switched capacitor modules, "chainlink circuits", are now offering the promise that the next generation of HVDC converters will be more efficient and have a reduced footprint. Examples of such converters are given in [2] and [3]. One class of these new converters is the Controlled Transition Bridge (CTB) where the director valves carry the main current for a significant portion of the period and the chainlink circuits provide a controlled traverse of voltage during the transitional period between the different director valves conducting, resulting in a trapezoid waveform being generated, Fig.…”

Section: Introductionmentioning

confidence: 99%

The augmented modular multilevel converter

Oates¹,

Dyke²,

Trainer³

2014

2014 16th European Conference on Power Electronics and Applications

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The Controlled Transition Bridge (CTB) is a class of converter topology that combines series connected semiconductor "director valves" with chains of switched capacitor modules, "chainlink circuits", in such a way that the director valves carry the main current for a significant portion of the period and the chainlink circuits provide a controlled traverse of voltage between different director valves conducting. This combination is applicable to HVDC where efficiency is paramount, since it allows thyristors or diodes to be used for the director valves to reduce the conduction losses, with the chainlink circuits providing commutation and direct control of the rate of change of transition voltage. Since the chainlink portion of the AMMC only has to manage the transition between the upper and lower director valves, the size of the capacitors in the individual sub-modules can be reduced, reducing the converter footprint. Also the trapezoidal waveform that results can be tailored to give reduced harmonic levels, so reducing filtering required for the AC waveform to meet regulations on distortion at the point of common coupling for the converter (PCC).An analysis is presented of an example of this type of converter where a modular multilevel converter (MMC) is combined with a conventional thyristor bridge, the Augmented MMC (AMMC). Various aspects of the operation of the bridge are discussed, including the management of the charge in the chainlink capacitors and the converter losses.

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Performance of a DC/AC/DC VSC System to Interconnect HVDC Systems

Cited by 22 publications

References 5 publications

Stability of DC/DC three terminals converter using Modular Multilevel Converters for HVDC systems

Stability of DC/DC three terminals converter using Modular Multilevel Converters for HVDC systems

Design and implementation of the low computational burden phase‐shifted modulation for DC–DC modular multilevel converter

The augmented modular multilevel converter

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