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In order to solve the problems of traditional modulated model predictive control (M2PC) in three-level indirect matrix converter-permanent magnet synchronous motor (TLIMC-PMSM) system, such as inaccurate sector selection and duty ratio calculation of M2PC. An improved modulated model predictive control based on virtual vector prediction (VVP-M2PC) is proposed and applied to TLIMC-PMSM system. Compared with the traditional M2PC, VVP-M2PC re-partitions the sectors of the three-level inverter stage and constructs a new virtual vector to reduce the current control error. In addition, the feasibility of this method is discussed from two aspects: computational complexity and theoretical error analysis. Finally, compared with MPC and traditional M2PC, the simulation and experiment results show that the algorithm can improve the speed and torque ripple of PMSM, and improve the quality and robustness of input and output waveforms of the system.

This paper proposes a hybrid control scheme that combines fractional-order sliding-mode control (FOSMC) with radial basis function neural network adaptive damping passivity-based control (RBFPBC) for modular multilevel converters (MMC) under non-ideal operating conditions. According to the passive control theory, we establish the Euler–Lagrange (EL) models of positive and negative sequences based on the unbalanced grid. A passivity-based controller that satisfies the energy dissipation law is designed. To enable rapid convergence of the system energy storage function, a radial basis function neural network (RBFNN) is introduced to adjust the injection damping adaptively. Additionally, a fractional-order sliding-mode controller (FOSMC) is designed. The fractional-order sliding mode surface used can improve tracking performance, and effectively suppressed the undesirable chattering phenomenon compared to the traditional sliding-mode control (SMC). Finally, combining the two control methods can effectively solve the issue of passivity-based control (PBC) being too dependent on parameters. The proposed hybrid control scheme enhances the ability of the system to resist disturbances, and improves its overall robustness. Simulation results demonstrate the feasibility and effectiveness of this control method.

Lavandin, as an important cash crop, is cultivated in Kunming, Yun-Gui Plateau of China. For the special growing environment, Lavandin was grown here and used to investigate the changes in the yield and chemical compositions of essential oils extracted from the flowers in different seasons. The essential oils were extracted by hydro-distillation and analysis by gas chromatography-mass spectrometry (GC-MS). Results indicated great changes in chemical composition depending on the season of harvesting. The yields of essential oils ranged from 2.0% to 3.8% among the seasons, and the highest yield was in the summer. Chemical composition data showed that the extracted oils were rich in oxygenated monoterpenes (55.4–81.4%), eucalyptol (38.7–49.8%), camphor (8.41–14.26%), α-bisabolol (6.6–25.5%), and linalool (4.6–12.5%). The contents of eucalyptol and α-bisabolol changed in a contrary trend with seasonal variations. The results provided new insight for Chinese Lavandin germplasm to be used in application and development, and reference to the researcher, the farmer, and investor for sustainable industrialization of the plant grown in the Yun-Gui Plateau of China, but also the similar plateau area of the sustainable developments.

Existing modulation and control strategies of direct matrix converter (DMC) cannot take both fast response and waveform quality into account, and there is also a lack of research on its application to complex scenarios such as power systems. In this paper, a mathematical model of DMC-UPFC is established based on the characteristics of DMC and the principle of unified power flow controller (UPFC), then a novel modulated model predictive control algorithm is proposed by combining the advantages of space vector modulation and model predictive control. In order to deal with the unbalanced conditions which is common in the power system, a compensation strategy is adopted as well. Simulation and experimental results verify that adequate dynamic performance and considerable waveform quality is achieved by using the proposed method. It can maintain power stability and current sinusoidal even under unbalanced conditions, which further verifies the feasibility of the scheme.

Sour soup is a traditional fermented food, enriched with abundant organic acids, minerals and other nutrients, which contribute to human and animal health. However, due to more consumer rejection of products caused by opportunistic contamination and sulfur-containing compounds during the spontaneous fermentation of sour soups, therefore, the development and utilization of sour soup additives can be tried, such as silage improvement applications. The purpose of the current study was to evaluated the effects of sour soup as an anaerobic fermentation additive on the fermentation characteristics, microbial diversity, community composition, and alkaloids of Broussonetia papyrifera . To compare the effects of sour soup additive on Broussonetia papyrifera silage, we selected two additives, Lactobacillus acidophilus (LAB) and sour soup (S), and no additive treatment (CK). The results indicated that additives treated with L. acidophilus and sour soup exhibited higher levels of crude protein (CP), WSC, and acetic acid (AA), as well as lower levels of neutral detergent fiber (NDF) and pH compared to the control silage, sour soup treatment has the best improvement effect on fermentation quality. Additions of L. acidophilus and S increased the abundance of Lactobacillus and decreased bacterial Shannon diversity index. Alkaloid analysis indicated that L. acidophilus additives increased the betaine content (beneficial alkaloids) of the fermentation, while the impact of sour soup additive was not great. Our structural equation model (SEM) demonstrates that the reduction in pH, induced by additives, is the primary driving factor behind the increase in silage protein and betaine content, as well as the decrease in bacterial diversity. This study showed that the addition of sour soup can be used as an additive to improve the quality of Broussonetia papyrifera silage fermentation, but its regulatory effect on bioactive substances (such as alkaloids) still needs further research.

At present, there are many researches on the nutritional quality and fermentation quality of forage silage by adding distillers’ grain and fruit residue, but few researches on the succession and function prediction of microbiotic community. In this study, the potential of Moutai distillers' grain (MDG), Rosa roxburghii pomace (RP) and Lactobacillus acidophilus (LAB) to improve silage quality during anaerobic storage of alfalfa and sorghum was investigated. Harvested alfalfa and sorghum were ensiled without (CK) or with MDG, RP, LAB, LAB + MDG or LAB + RP for 45 days at 21–25 °C. Compared with the uninoculated control, alfalfa silage inoculated with LAB + MDG presented better nutrient retention, where the lactic acid (LA) content was increased by 84.62% and the ammonia nitrogen (AN) content was reduced by 38.52%. Similarly, in sorghum silage, both inoculation with LAB + MDG and inoculation with LAB + RP effectively increased nutrient retention, increased the LA content and reduced the AN content. The proportion of Lactobacillus increased in sorghum and alfalfa silage after 45 days of fermentation. Inoculation of alfalfa and sorghum with RP or LAB + MDG significantly increased the relative abundance of lactic acid bacteria in silage, especially Lactobacillus plantarum , which was the main dominant strain. The addition of MDG to the feeds not only effectively retained the crude protein (CP) content of the feeds for better retention of their nutritional value but also significantly reduced the contents of neutral detergent fiber (NDF) and acid detergent fiber (ADF), which improved the digestibility and utilization of the feeds. In addition, the addition of MDG further promoted the proliferation of Lactobacillus and increased their abundance in the silage, thus contributing to the improvement of fermentation quality and preservation of silage. In summary, MDG, LAB + MDG, and RP + LAB resulted in higher-quality silage, but the addition of MDG was more cost effective and therefore is recommended for application in production.

Objective Wet distiller’s grains (WDG) are rich in crude protein, yet challenging to preserve. Nevertheless, incorporating WDG into total mixed ration (TMR) silage holds promise for enhancing fermentation quality. This study investigated the effects of varying WDG proportions on nitrogen composition, fermentation quality, and microorganisms in TMR silage. Methods Three TMR formulations were prepared: (1) 0% WDG (T0), (2) 15% WDG (T15), and (3) 30% WDG (T30) were ensiled for 7, 15, 30 and 60 days. Results After 7 days of ensiling, butyric acid was detected in T0 and T15 groups, while T30 exhibited significantly lower levels ( p  < 0.05). Both T15 and T30 treatments led to improved V-scores of TMR silage. Non-protein nitrogen (NPN) production was slower in T30, with significant increases observed in NPN levels for T0 and T15 after 30 days (p  <  0.05). However, the abundance of Clostridium was extremely low in the present study. Protein degradation and and butyric acid production may be attributed to Weissella . Conclusion The fermentation quality of TMR silage is always decreasing during storage, so its storage time should be minimized. Incorporating 30% WDG reduced abundance of Weissella , resulting in less protein degradation and better fermentation quality in TMR silage.

The total harmonic distortion and switching stress of a three-level direct matrix converter (TLDMC) is greatly reduced in comparison with those of a conventional matrix converter (MC). Meanwhile, the TLDMC leads to major advantages in comparison with existing multi-level AC–DC–AC converter topologies in terms of reduced switch counts and lowered switching power loss. In this paper, a space vector pulse width amplitude modulation (SVPWAM) strategy for the TLDMC is proposed, which can reduce the number of switching actions and improve the voltage utilization by eliminating the zero vector of each sector. An indirect modulation model of a TLDMC is discussed according to the topology of TLDMC in this paper. For the space vector modulation of the TLDMC, the space vector pulse width modulation (SVPWM) with a zero-vector of the fictitious rectifier stage is improved to form the SVPWAM. In addition, the virtual space vector pulse width modulation (VSVPWM) strategy is used for the fictitious inverter stage. Finally, simulation and experimental results verify the correctness of the proposed method.

Background This study aimed to investigate the effect of phenyllactic acid as an additive on silage fermentation and bacterial community of reed canary grass (RCG, Phalaris arundinacea L.) on the Qinghai Tibetan Plateau. At the heading stage, RCG was harvested, chopped and ensiled in small bag silos. The silage was treated without (control, 1.0 g/mL sterile water, on a fresh matter basis (FM)) or with phenyllactic acid (PLA, 3 mg/mL, FM), antimicrobial additive (PSB, a mixture of potassium sorbate and sodium benzoate, 2%, FM), lactic acid bacteria inoculant (LABi, L. plantarum  +  L. curvatus , 1 × 10 6  cfu/g, FM) and PLA + LABi, and then stored in a dark room at the ambient temperature (5 ~ 15 °C) for 60 days. Results Compared with control, PLA decreased lactic acid, acetic acid and ammonia-N contents, and subsequently increased CP content of RCG silage. PLA enhanced the growth of lactic acid bacteria and reduced the count of yeasts ( P  < 0.05) in RCG silage, with reduced bacterial richness index (Chao1), observed operational taxonomic units and diversity index (Simpson). In relative to control, moreover, PLA and PLA + LABi increased the relative abundance of Lactococcus in RCG silage by 27.73 and 16.93%, respectively. Conclusions Therefore, phenyllactic acid at ensiling improved nutritional quality of RCG silage by advancing the disappearance of yeasts and the dominance of Lactococcus .

Background Sainfoin ( Onobrychis viciifolia Scop) is not only a high-quality legume forage, but also a nectar-producing plant. Therefore, the flower color of sainfoin is an important agronomic trait, but the factors affecting its flower phenotype are still unclear. To gain insights into the regulatory networks associated with metabolic pathways of coloration compounds (flavonoids or anthocyanins) and identify the key genes, we conducted a comprehensive analysis of the phenotype, metabolome and transcriptome of WF and AF of sainfoin. Results Delphinidin, petunidin and malvidin derivatives were the main anthocyanin compounds in the AF of sainfoin. These substances were not detected in the WF of sainfoin. The transcriptomes of WF and AF in sainfoin at the S1 and S3 stages were obtained using the Illumina HiSeq4000 platform. Overall, 10,166 (4273 upregulated and 5893 downregulated) and 15,334 (8174 upregulated and 7160 downregulated) DEGs were identified in flowers at S1 and S3 stages, respectively (WF-VS-AF). KEGG pathway annotations showed that 6396 unigenes were annotated to 120 pathways and contained 866 DEGs at S1 stages, and 6396 unigenes were annotated to 131 pathways and included 1546 DEGs at the S3 stage. Nine DEGs belonging to the “flavonoid biosynthesis”and “phenylpropanoid biosynthesis” pathways involved in flower color formation were identified and verified by RT-qPCR analyses. Among these DEGs, 4CL3 , FLS , ANS , CHS , DFR and CHI2 exhibited downregulated expression, and F3H exhibited upregulated expression in the WF compared to the AF, resulting in a decrease in anthocyanin synthesis and the formation of WF in sainfoin. Conclusions This study is the first to use transcriptome technology to study the mechanism of white flower formation in sainfoin. Our transcriptome data will be a great enrichment of the genetic information for sainfoin. In addition, the data presented herein will provide valuable molecular information for genetic breeding and provide insight into the future study of flower color polymorphisms in sainfoin.