Research on Mixed Logic Dynamic Modeling and Finite Control Set Model Predictive Control of Multi-Inverter Parallel System

Parallel connection of multiple inverters is an important means to solve the expansion,reserve and protection of distributed power generation,such as photovoltaics.In view of the shortcomings of traditional droop control methods such as weak anti-interference ability,low tracking accuracy of inverter output voltage and serious circulation phenomenon,a finite control set model predictive control(FCS-MPC)strategy of microgrid multiinverter parallel system based on Mixed Logical Dynamical(MLD)modeling is proposed.Firstly,the MLD modeling method is introduced logical variables,combining discrete events and continuous events to form an overall differential equation,which makes the modeling more accurate.Then a predictive controller is designed based on the model,and constraints are added to the objective function,which can not only solve the real-time changes of the control system by online optimization,but also effectively obtain a higher tracking accuracy of the inverter output voltage and lower total harmonic distortion rate(Total Harmonics Distortion,THD);and suppress the circulating current between the inverters,to obtain a good dynamic response.Finally,the simulation is carried out onMATLAB/Simulink to verify the correctness of the model and the rationality of the proposed strategy.This paper aims to provide guidance for the design and optimal control of multi-inverter parallel systems.

Numerical investigation on the flow characteristics of a reverse-polarity plasma torch by two-temperature thermal non-equilibrium modelling

A two-temperature(2 T)thermal non-equilibrium model is developed to address the thermal nonequilibrium phenomenon that inevitably exists in the reverse-polarity plasma torch(RPT)and applied to numerically investigate the plasma flow characteristics inside and outside the RPT.Then,a detailed comparison of the results of the 2 T model with those of the local thermal equilibrium(LTE)model is presented.Furthermore,the temperature of the plasma jet generated by a RPT and the RPT’s voltage are experimentally measured to compare and validate the result obtained by different models.The differences of the measured excitation temperature and the arc voltage between the 2 T model and experimental measurement are less than 13%and 8%,respectively,in all operating cases,validating the effectiveness of the 2 T model.The LTE model overestimates the velocity and temperature distribution of the RPT and its plasma jet,showing that thermal non-equilibrium phenomena cannot be neglected in the numerical modelling of the RPT.Unlike other common hot cathode plasma torches,the thermal non-equilibrium phenomenon is found even in the arc core of the RPT,due to the strong cooling effect caused by the big gas flow rate.

FCS-MPC Strategy for PV Grid-Connected Inverter Based on MLD Model

In the process of grid-connected photovoltaic power generation,there are high requirements for the quality of the power that the inverter breaks into the grid.In this work,to improve the power quality of the grid-connected inverter into the grid,and the output of the system can meet the grid-connected requirements more quickly and accurately,we exhibit an approach toward establishing a mixed logical dynamical(MLD)model where logic variables were introduced to switch dynamics of the single-phase photovoltaic inverters.Besides,based on the model,our recent efforts in studying the finite control set model predictive control(FCS-MPC)and devising the output current full state observer are exciting for several advantages,including effectively avoiding the problem of the mixed-integer quadratic programming(MIQP),lowering the THD value of the output current of the inverter circuit,improving the quality of the power that the inverter breaks into the grid,and realizing the current output and the grid voltage same frequency and phase to meet grid connection requirements.Finally,the effectiveness of the mentioned methods is verified by MATLAB/Simulink simulation.

Characterization of the P450 Monooxygenase LobP1 as C-32 Hydroxylase in Lobophorin Biosynthesis

Lobophorins(LOBs)belong to a large family of spirotetronate antibiotics with antibacterial and antitumor activities.In this study,we demonstrated the function of LobP1,a P450 monooxygenase encoded in the LOB biosynthetic gene cluster,by in vivo deletion and in vitro biochemical assays.The disruption of lobP1 led to the isolation of three new LOBs derivatives(3-5)and three known ones(6-8)without the hydroxyl group at C-32.LobP1 was shown to have relatively broad substrate scope.Determining the kinetic parameters of LobP1 towards different substrates revealed that LobP1 preferred substrate with a nitrosugar.The new LOBs 3-5 displayed significant antibacterial activities against Bacillus subtilis and Micrococcus luteus with MIC values of 0.125 to 1μg·mL^(-1),and the major product LOB E(6)from the∆lobP1 mutant showed moderate cytotoxic activities against several cancer cell lines.

Talachalasins A-C,Undescribed Cytochalasans with a 16β-Methyl or 2-Oxabicyclo[3.3.1]nonan-3-one unit from the Deep-Sea-Derived Fungus Talaromyces muroii sp.SCSIO 40439

Comprehensive Summary Talachalasins A-C(1-3),three new cytochalasans(CYTs),were isolated from deep-sea-derived fungus Talaromyces muroii sp.SCSIO 40439.The structures of 1-3,including absolute configurations,were determined based on HRESIMS,NMR spectroscopic data,ECD comparison,and single crystal X-ray diffraction analysis.Talachalasins A-C(1-3)represented the first examples of cytochalasans possessing a unique 16β-methyl group,distinct from>500 reported CYTs.Talachalasin C(3)was an unprecedented 20,21-seco-cytochalasans characterized by a 2-oxabicyclo[3.3.1]nonan-3-one unit.Talachalasin A(1)displayed moderate cytotoxic activity against four tumor cell lines(IC_(50)3.40-10.02μM).Talachalasin B(2)showed comparable anti-RSV and HSV-1 activities(IC5012.5μM or IC5020.0μM).

Off-policy correction algorithm for double Q network based on deep reinforcement learning

A deep reinforcement learning(DRL)method based on the deep deterministic policy gradient(DDPG)algorithm is proposed to address the problems of a mismatch between the needed training samples and the actual training samples during the training of in-telligence,the overestimation and underestimation of the existence of Q-values,and the insufficient dynamism of the intelligence policy exploration.This method introduces the Actor-Critic Off-Policy Correction(AC-Off-POC)reinforcement learning framework and an improved double Q-value learning method,which enables the value function network in the target task to provide a more accurate evaluation of the policy network and converge to the optimal policy more quickly and stably to obtain higher value returns.The method is applied to multiple MuJoCo tasks on the Open AI Gym simulation platform.The experimental results show that it is better than the DDPG algorithm based solely on the different policy correction framework(AC-Off-POC)and the conventional DRL algorithm.The value of returns and stability of the double-Q-network off-policy correction algorithm for the deep deterministic policy gradient(DCAOP-DDPG)pro-posed by the authors are significantly higher than those of other DRL algorithms.

大孔高镍LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)正极材料的制备及其电化学性能研究

本工作以聚甲基丙烯酸甲酯(PMMA)微球组装成的胶晶模板作为铸模,溶胶-凝胶法辅助获得大孔LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)正极材料.结果表明,利用PMMA作为造孔剂,形成了由100 nm的颗粒堆积而成的大孔结构,这种结构有效地提高了材料的倍率性能和循环稳定性.大孔NCM811在0.1C的首次放电比容量为190.3 mAh·g^(−1).2C倍率下NCM811纳米颗粒的放电比容量仅为129.3 mAh·g^(−1),而大孔NCM811的放电比容量为149.8 mAh·g^(−1).0.5C倍率下循环400次后大孔NCM811的容量保持率为83.02%,明显高于纳米颗粒材料的38.59%.

Light doping of tungsten into copper-platinum nanoalloys for boosting their electrocatalytic performance in methanol oxidation

Coupling the bi-functional mechanism with compressive lattice strain might be an effective way to boost the electrocatalysis of platinum(Pt)-based nanoparticles for methanol oxidation reaction(MOR).This strategy weakens the chemisorption of poisoning CO-like intermediates generated during MOR on the active Pt sites by lowering their d-band center.In this context,we herein report the synthesis of ternary copper-tungsten-platinum(CuWPt)nanoalloys with light doping of W element by simply co-reducing their precursors at elevated temperature.In this ternary alloy system,the presence of only small amount of W element not only weakens the chemisorption of CO-like intermediates by lowering the Pt d-band center through compressive lattice strain,but also cleans the active Pt sites by“hydrogen spillover effect”,endowing the as-prepared CuWPt nanoalloys at an appropriate Cu/W/Pt ratio with good activity for MOR.In specific,the ternary CuWPt alloy nanoparticles at a Cu/W/Pt molar ratio of 21/4/75 show a specific activity of 2.5 mA·cm^(−2)and a mass activity of 2.11 A·mg^(−1)with a better durability,outperforming those ternary CuWPt alloy nanoparticles at other Cu/W/Pt ratios,binary CuPt alloys and commercial Pt/C catalyst as well as a large number of reported Pt-based electrocatalysts.In addition,a single direct methanol fuel cell(DMFC)assembled using ternary CuWPt nanoalloys as anodic catalysts shows a power density of 24.3 mW·cm^(−2)and an open-circle voltage of 0.6 V,also much higher than those of the single DMFC assembled from commercial Pt/C catalysts.