MMC-MTDC transmission system with partially hybrid branches

This paper proposes a hybrid submodule modular multilevel converter (MMC) topology which is suitable for multi terminal direct current (MTDC) transmission systems. Each arm of the proposed MMC topology consists of a half-bridge submodule (HBSM) branch and two parallel full-bridge submodule (FBSM) branches. Comparing with the conventional MTDC transmission system, the proposed topology can selectively block the DC fault current and isolate the corresponding fault line without expensive DC circuit breakers (DCCBs). Thus, the influence range of the DC fault can be reduced and the reliability of the power supply can be improved as well. The corresponding modulation and voltage balancing strategies are developed for the proposed hybrid MMC topology. The feasibility of the proposed topology and control strategy is verified in the MATLAB/ Simulink simulation

Variation of interlinked-phenolics in <i>Miscanthus</i> (n = 79).

<p>(A) Interlinked-phenolics in the KOH-extractable and non-KOH-extractable residues; (B) Total interlinked-phenolic compositions. H-: <i>p</i>-Hydroxybenzaldehyde, G-: Vanillin, S-: Syringaldehyde, AV-: Acetovanillone, AS-: Acetosyringone, PCA-: <i>p-</i>Coumaric acid, FA-: Ferulic acid, SA-: Sinapic acid.</p

Correlation analysis among lignin, interlinked-phenolics and biomass saccharification in <i>Miscanthus</i>.

<p>(A) Correlation between lignin content and hexoses yield; (B) Correlation between total interlinked-phenolics and hexoses yield. * and ** Indicated the significant correlation coefficient values at <i>p</i><0.05 and 0.01 (n = 79), respectively.</p

Analysis of monolignol and interlinked-phenolics compositions in the representative <i>Miscanthus</i> samples.

<p>(A) Monolignol composition; (B) S/G ratio; (C) Total interlinked-phenolics.</p

The Minor Wall-Networks between Monolignols and Interlinked-Phenolics Predominantly Affect Biomass Enzymatic Digestibility in <i>Miscanthus</i>

<div><p>Plant lignin is one of the major wall components that greatly contribute to biomass recalcitrance for biofuel production. In this study, total 79 representative <i>Miscanthus</i> germplasms were determined with wide biomass digestibility and diverse monolignol composition. Integrative analyses indicated that three major monolignols (S, G, H) and S/G ratio could account for lignin negative influence on biomass digestibility upon NaOH and H₂SO₄ pretreatments. Notably, the biomass enzymatic digestions were predominately affected by the non-KOH-extractable lignin and interlinked-phenolics, other than the KOH-extractable ones that cover 80% of total lignin. Furthermore, a positive correlation was found between the monolignols and phenolics at <i>p</i><0.05 level in the non-KOH-extractable only, suggesting their tight association to form the minor wall-networks against cellulases accessibility. The results indicated that the non-KOH-extractable lignin-complex should be the target either for cost-effective biomass pretreatments or for relatively simply genetic modification of plant cell walls in <i>Miscanthus</i>.</p></div