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Current scraper conveyors with permanent magnet synchronous motors often improve their efficiency by updating the mechanical structure of their drive systems, few efforts are made to optimize the control of permanent magnet synchronous motors. This paper fills the gap by involving maximum torque per ampere (MTPA) and flux-weakening controls to improve the dual-motor drive system of scraper conveyors. Given the direct-axis current, the proposed system reduces the motor loss by adopting MTPA control to obtain the maximum torque per ampere. By using flux-weakening control to increase the speed regulation range of scraper conveyors, the coal output of a scraper conveyor can be relatively stable under various production loads. To balance the power of two motors, the proposed system applies the master-slave control that takes the rear motor as the master and the front motor as the slave, and gives the master's torque setpoint to the slave's MTPA and flux-weakening control systems. The effectiveness of the proposed system is evaluated by using AMEsim and Matlab/Simulink to simulate the scraper conveyor and its dual-motor drive system, respectively. The results show that the stator current under MTPA can be stable at 130.1 A when the motor load suddenly raised, while the stator current under traditional vector control is stable at 149.2 A. MTPA control outperforms the vector control, as the smaller stator current implies the better system when the same output torque maintained. Flux-weakening control extends the speed regulation range from 0-750 r/min to 0-850 r/min. Master-slave control maintains the same output torques of the master and the slave, leading to the balanced dual-motor power.

With the continuous promotion of the “dual carbon” idea, future power generation will rely heavily on renewable energy sources. As an effective utilization form of clean power sources, it is of positive significance to study the trading strategy of microgrids in the intelligent power distribution system under the influence of carbon quota. In this research, a bi-level optimization method is used to build a trading model of the distribution-side power market, with the upper-level planning aiming to reduce the cost of distribution system operators and the lower-level planning aiming to increase the revenue of microgrids. Secondly, the genetic algorithm and sequential quadratic planning algorithm are applied to the upper and bottom models to determine the optimal clearing strategy for the microgrid and the optimal scheduling scheme for the distribution system operator, respectively. Finally, a typical day is used as an example to analyze in detail the market trading strategy of a multi-microgrid intelligent distribution system under the influence of carbon quota, and the effectiveness of the method described in this paper is verified.

Aluminum matrix composites (AMCs) reinforced by 5 wt% B4C particles were fabricated by direct laser deposition (DLD) technology. The phase composition, microstructure, and microhardness of the B4C/aluminum matrix composites (B4C/AMCs) were analyzed by OM, XRD, SEM, TEM, EBSD, microhardness test and molecular dynamics simulation (MD) in detail. The results show that acicular microstructure of AlB12 and Al4C3 are formed in the B4C/AMCs fabricated by DLD. With the addition of B4C, the crystallographic orientation of AMCs changes from (001) texture to random orientation distribution, and the microhardness increases by about 65%. During the DLD process, boron atoms and carbon atoms are released by B4C decomposition instead of diffusing through the solid–liquid interface between Al and B4C, and they react with the liquid Al to produce AlB12 and Al4C3 in the molten pool. Moreover, B and C atoms distribute along a strip orientation in the molten pool, which may be retained after the cooling to form the acicular microstructures. This work demonstrates the possibility and good prospects of obtaining AMCs reinforced with B4C, AlB12 and Al4C3 phases by the DLD technique and provides new insights into the microstructural evolution of the composites. [ABSTRACT FROM AUTHOR]

Health impact assessment (HIA) is an approach to identification of potential health benefits or hazards in urban planning schemes. Quantitative HIA provides uniform and comparable health outcomes (e.g., the morbidity of a specific disease), which could effectively assist planning decisions. However, there are currently few quantitative HIA methods specifically for urban planning applications. Based on a review of existing HIA methods, this paper has developed a quantitative HIA system for urban planning schemes in China, and specifically evaluates health risks, health behaviors, and health outcomes. Taking the Territorial and Spatial Master Plan of the Gucun Township of Shanghai as an example, we have illustrated how to evaluate the reduced health risks and increased health behaviors, as well as how to calculate changes in potential health outcomes in order to provide a reference for relevant HIA practices. [ABSTRACT FROM AUTHOR]

Under the vision of carbon neutrality, carbon dioxide emission allowance targets are gradually decreasing, and clean power sources will penetrate in an ultra-high proportion. The traditional distribution grid dispatching model needs to solve the problems of carbon emission compliance and strong intermittent leveling of clean power sources. Based on the analysis of the coupling relationship between carbon emission index and the economic cost of electric power, this paper proposes a novel dispatching model for the future state distribution grid with carbon and electric power couping, proposes an optimal dispatching strategy for distribution grid based on the second-order cone planning model for several scenarios of increasing carbon emission cost of system operaion, and verifies the effectiveness of the proposed method in the improved IEEE 33-node system. The example results show that the output and power generation cost of each distribution network change after considering the carbon emission index.