Intra-arm Balancing Control for Modular Multilevel Converter with Cell Loading Operated under High Power Imbalances

Multiport converters with a large number of ports have been explored for integrated generation units or batteries. An attractive candidate multiport converter has been developed based on the modular multilevel converter (MMC) with cell loading. Accordingly, this study proposes a control strategy for a multiport converter based on the MMC operated under high power imbalances among cells. Owing to this power imbalance, the multiport converter requires an additional circulating current (intra-arm balancing current) to provide balanced three-phase grid currents and balanced capacitor voltages in all cells. In a previous study, the minimum required intra-arm balancing current was calculated offline and applied according to the loading condition. This method may require a high-capacity memory for the controller. In contract, this study proposes an active control method for minimizing the intra-arm balancing current online. Experimental results reveal that the multiport converter achieves balanced three-phase currents with a total harmonic distortion of 3.13% and balanced capacitor voltages with an error of 0.1% under maximum power imbalance among cells. © 2024 The Institute of Electrical Engineers of Japan.Intra-arm Balancing Control for Modular Multilevel Converter with Cell Loading Operated under High Power ImbalancesacceptedVersio

Improvement of Waveform for High Frequency AC-linked Matrix Converter with SVM based on Virtual Indirect Control

Abstract-This paper proposes a dead-time compensation for a secondary side matrix converter with space vector modulation in order to improve waveform of the high frequency AC-linked matrix converter. The proposed system is constructed by backto-back configuration of two three-phase to single phase matrix converters and a high frequency transformer. In order to improve the waveform, the dead-time compensation for the primary side matrix converter has been proposed. However, the dead-time compensation for the secondary side matrix converter with space vector modulation based on virtual indirect control has not been discussed. In this paper, the dead-time compensation method for the secondary side matrix converter is revealed. As the result, it is confirmed that the average output voltage error between the command and measured voltage is reduced by 20% at low modulation index by adopting the deadtime compensation. Finally, a 2-kW prototype is demonstrated by experiment. The efficiency and the input power factor at the maximum point were obtained by 91.4% and 0.997. Moreover, the input current total harmonic distortion (THD) is 5.65% at 2-kW output power

Verification of Parallel Connected Multiple Motor Drive System with

Abstract This paper discusses a multi-parallel drive system for permanent magnet synchronous motors PMSMs). This system proposes to use two different functions of inverter, a main inverter with V/f control to control the speed of all parallel connected PMSMs. Then, each of PMSM is individually connected with an auxiliary inverter. The auxiliary windings which are used in the auxiliary inverter are placed in the slots together with the conventional windings. In addition, implementation of the damping control in the auxiliary inverter is discussed and the stability analysis is evaluated in order to suppress the speed and torque vibrations which are caused from the resonance between the inertia moment and the synchronous reactance. The simulation and experimental results demonstrate the effectiveness of the proposed system. Moreover, the relationship between the damping gain and the output power of the auxiliary inverter is clarified. From the results, it can be confirmed that if the application that is required a slow response is applied in the auxiliary inverter, then the power capacity of the auxiliary inverter can achieve the smallest which is equivalent to 10% of the main inverter power capacity

The ADAXIALIZED LEAF1 gene functions in leaf and embryonic pattern formation in rice

AbstractThe adaxial–abaxial axis in leaf primordia is thought to be established first and is necessary for the expansion of the leaf lamina along the mediolateral axis. To understand axis information in leaf development, we isolated the adaxialized leaf1 (adl1) mutant in rice, which forms abaxially rolled leaves. adl1 leaves are covered with bulliform-like cells, which are normally distributed only on the adaxial surface. An adl1 double mutant with the adaxially snowy leaf mutant, which has albino cells that specifically appear in the abaxial mesophyll tissue, indicated that adl1 leaves show adaxialization in both epidermal and mesophyll tissues. The expression of HD-ZIPIII genes in adl1 mutant increased in mature leaves, but not in the young primordia or the SAM. This indicated that ADL1 may not be directly involved in determining initial leaf polarity, but rather is associated with the maintenance of axis information. ADL1 encodes a plant-specific calpain-like cysteine proteinase orthologous to maize DEFECTIVE KERNEL1. Furthermore, we identified intermediate and strong alleles of the adl1 mutant that generate shootless embryos and globular-arrested embryos with aleurone layer loss, respectively. We propose that ADL1 plays an important role in pattern formation of the leaf and embryo by promoting proper epidermal development

Fertilization controls tiller numbers via transcriptional regulation of a MAX1-like gene in rice cultivation

低施肥でも穂数が減らず、収量を確保できるイネを開発 --ゲノム編集技術で、SDGs時代の新しいイネ遺伝資源を創成--. 京都大学プレスリリース. 2023-06-13.Fertilization controls various aspects of cereal growth such as tiller number, leaf size, and panicle size. However, despite such benefits, global chemical fertilizer use must be reduced to achieve sustainable agriculture. Here, based on field transcriptome data from leaf samples collected during rice cultivation, we identify fertilizer responsive genes and focus on Os1900, a gene orthologous to Arabidopsis thaliana MAX1, which is involved in strigolactone biosynthesis. Elaborate genetic and biochemical analyses using CRISPR/Cas9 mutants reveal that Os1900 together with another MAX1-like gene, Os5100, play a critical role in controlling the conversion of carlactone into carlactonoic acid during strigolactone biosynthesis and tillering in rice. Detailed analyses of a series of Os1900 promoter deletion mutations suggest that fertilization controls tiller number in rice through transcriptional regulation of Os1900, and that a few promoter mutations alone can increase tiller numbers and grain yields even under minor-fertilizer conditions, whereas a single defective os1900 mutation does not increase tillers under normal fertilizer condition. Such Os1900 promoter mutations have potential uses in breeding programs for sustainable rice production

Total synthesis of TMG-chitotriomycin based on an automated electrochemical assembly of a disaccharide building block

The total synthesis of TMG-chitotriomycin using an automated electrochemical synthesizer for the assembly of carbohydrate building blocks is demonstrated. We have successfully prepared a precursor of TMG-chitotriomycin, which is a structurally-pure tetrasaccharide with typical protecting groups, through the methodology of automated electrochemical solution-phase synthesis developed by us. The synthesis of structurally well-defined TMG-chitotriomycin has been accomplished in 10-steps from a disaccharide building block

Morphological character changes through decapodid-stage larva and juveniles in the ghost shrimp Nihonotrypaea harmandi from western Kyushu, Japan: Clues for inferring pre- and post-settlement states and processes

Some decapod crustaceans release larvae from estuarine or coastal shores to coastal oceans. Decapodids (last-stage larvae) return home, settle, and metamorphose into juveniles I, which go through further instars. Several morphological characters degenerate or develop in response to lifestyle transitions. Using a burrow-dwelling callianassid shrimp, Nihonotrypaea harmandi, inhabiting an intertidal sandflat in a coastal boundary layer adjacent to coastal ocean, this study described morphological changes and drew inferences about states and processes in its early life history. Decapodid and juveniles were differentiated by linea thalassinica on carapace. In the laboratory, the decapodid stage lasted 3-6d. Given choice between sandy sediments from coastal ocean bed and adult habitat, decapodids exhibited no preference, suggesting broad receptiveness. The shortest durations of the juvenile-I, -II, and -III were estimated at 6d each. Starved decapodids normally metamorphosed into juveniles I, showing secondary lecithotrophy. The non-feeding state could be extended through the juvenile I (and possibly juvenile II), where the mean total lengths of shrimps reared in groups with food (diatoms) remained about 4.6mm. Post-settlement decapodids reared individually resumed feeding. The rostrum lengths in decapodids were ≥0.36mm on the initial two dates (Days 0 and 1), after which the mean values rapidly reduced to 0.30-0.36mm on Day 2 and below 0.30mm thereafter. The pereiopod exopods disappeared through the decapodid stage from four pairs to almost zero by Day 4. In the coastal ocean, no juveniles occurred, and almost all decapodids had rostrum lengths ≥0.30mm and 3 or 4 pereiopod exopods, suggesting their pre-settlement state. Of the smallest shrimps collected on the sandflat for their subsequent rearing there, 74% were estimated to be Day-0 or -1 decapodids based on their rostrum lengths. This and the laboratory experimental results suggest (1) the acquisition of competence for settlement by newly-metamorphosed decapodids while in the coastal ocean, which was nevertheless realized there and (2) their rapid transport by flood tidal currents from coastal ocean to sandflat. The newly-settled decapodids grew steadily at 0.2mmd-1 in total length. The reared juveniles reached the smallest adult size in 80d. The uropod expod changed from elliptical to sub-circular in shape markedly around the termination of the juvenile II or III, suggesting the acquisition of ventilating function for benthic life. Overall, the post-settlement shrimps can be staged by total-length ranges as 4-5.5mm for decapodids, 5.5-10mm for juveniles, and 10-20mm for sub-adults. •Decapodid and juveniles of a callianassid shrimp were reared in laboratory and field.•Ontogenetic morphological change and growth in decapodid and juveniles were given.•Feeding mode, substratum selectivity, and duration for decapodid stage were examined•Two degenerating characters gave clues to infer states in field-collected decapodids.•One developing character in juveniles was related with burrow-dwelling lifestyle

Effect of octanoic acid-rich formula on plasma ghrelin levels in cachectic patients with chronic respiratory disease

<p>Abstract</p> <p>Background</p> <p>For cachectic patients with chronic respiratory disease (CRD), conventional enteral nutrition formula is an optional treatment to maintain energy balance. The molecular mechanisms by which enteral nutrition formula controls appetite and weight remain unknown. We examined whether enteral nutrition formula rich in octanoic acids would increase plasma levels of ghrelin, an appetite-stimulating hormone produced in the stomach, in cachectic patients with CRD.</p> <p>Methods</p> <p>Plasma ghrelin profiles in cachectic patients with CRD were assessed and compared with those in age- and sex-matched controls. Plasma levels of acyl-ghrelin, an active ghrelin modified by octanoic acids, and desacyl-ghrelin were measured separately. We examined changes in 24-h plasma ghrelin profiles before and after single administration of the formula. We also evaluated the effects of 2-week administration of the formula on plasma ghrelin levels and nutritional status in patients.</p> <p>Results</p> <p>The ratio of acyl-ghrelin to desacyl-ghrelin in plasma was lower in patients than in controls. Single administration of the formula did not change plasma desacyl-ghrelin levels, but induced an increase in acyl-ghrelin levels. Two-week treatment with the formula was effective in increasing weight and acyl-ghrelin, along with improving nutritional status in patients.</p> <p>Conclusion</p> <p>These results show that the formula contributes to increased weight, which may be associated with induction of acyl-ghrelin production in cachectic patients with CRD.</p

A Young Brown Dwarf Companion to DH Tauri

We present the detection of a young brown dwarf companion DH Tau B associated with the classical T Tauri star DH Tau. Near-infrared coronagraphic observations with CIAO on the Subaru Telescope have revealed DH Tau B with H = \~15 mag located at 2.3" (330 AU) away from the primary DH Tau A. Comparing its position with a Hubble Space Telescope archive image, we confirmed that DH Tau A and B share the common proper motion, suggesting that they are physically associated with each other. The near-infrared color of DH Tau B is consistent with those of young stellar objects. The near-infrared spectra of DH Tau B show deep water absorption bands, a strong K I absorption line, and a moderate Na I absorption line. We derived its effective temperature and surface gravity of Teff = 2700 -- 2800 K and log g = 4.0--4.5, respectively, by comparing the observed spectra with synthesized spectra of low-mass objects. The location of DH Tau B on the HR diagram gives its mass of 30 -- 50 M_Jupiter.Comment: 10 pages, 14 figures, 1 table, accepted for publication in Ap