An improved nondominated sorting genetic algorithm-II (INSGA-II) has been proposed for optimal planning of multiple distributed generation (DG) units in this paper. First, multiobjective functions ...that take minimum line loss, minimum voltage deviation, and maximal voltage stability margin into consideration have been formed. Then, using the proposed INSGA-II algorithm to solve the multiobjective planning problem has been described in detail. The improved sorting strategy and the novel truncation strategy based on hierarchical agglomerative clustering are utilized to keep the diversity of population. In order to strengthen the global optimal searching capability, the mutation and recombination strategies in differential evolution are introduced to replace the original one. In addition, a tradeoff method based on fuzzy set theory is used to obtain the best compromise solution from the Pareto-optimal set. Finally, several experiments have been made on the IEEE 33-bus test case and multiple actual test cases with the consideration of multiple DG units. The feasibility and effectiveness of the proposed algorithm for optimal placement and sizing of DG in distribution systems have been proved.
AC-DC-AC converter-fed induction motor (IM) drive is mainly realized by back-to-back three-phase converters. However, fault in a single semiconductor switch will make it inoperative. To enable ...continued controllable operation in case of the faults occurring in the converter, the five-leg converter with a shared leg between the grid and load sides is a possible solution. However, this topology poses an inherent two-objective control problem, because its grid and load sides should be controlled simultaneously. More importantly, the potential increase of the shared-leg current may destroy the converters. In this paper, a new control scheme based on the FCS-MPC combined with intrinsic characteristic of the five-leg converter is proposed for independent control of the rectifier and inverter subsystem with the shared-leg overcurrent constraint. The condition for independent control is analyzed. In order to give a complete evaluation of the proposed control scheme, the conventional pulsewidth modulation (PWM) control scheme is conducted for comparison. Experimental results are provided to validate the effectiveness of the proposed scheme.
The nonredundant voltage-source inverter, which exploits the possibility of minimum additional components for reconfiguration and operation, is a promising solution to manage faults in one inverter ...leg. However, control schemes at prefault and postfault conditions are always designed, separately making it hard for control scheme adaptation from normal to fault tolerant. In order to achieve smooth transitions from prefault to postfault, an embeddable fault-tolerant method based on predictive torque control (PTC) is proposed. A generalized voltage vectors, switching command, and cost function accounting for both healthy and faulty conditions are introduced to carry out a general control scheme. A novel fault-diagnosis method based on probability density analysis of the sampling currents is presented for open-circuit fault isolation under PTC scheme. Seamless likely and rapid transient processes from fault occurrence to postfault operation are achieved. Experimental results have demonstrated that the proposed scheme can make power switch fault easily managed by the controller itself.
Objectives To assess the efficacy of acceptance and commitment therapy (ACT) for patients with chronic pain. Materials and methods The research conducted a systematic search of the Cochrane Library, ...Web of Science, PubMed, EMBASE, PsycINFO, and Cumulative Index of Nursing and Allied Health Literature (CINAHL) databases following the PRISMA guidelines. The retrieval time limit was from the establishment of the database to October 2023. A meta-analysis was carried out for the randomized controlled trials (RCTs) that meet the inclusion and exclusion criteria by using RevMan 5.3. Results Twenty-one RCTs were included. At post-treatment, a significant medium effect size (ES) was found in measuring pain interference, functional impairment, pain acceptance, psychological inflexibility, and depression; Pain intensity, anxiety, and quality of life (QOL) had a small ES. At three months post-treatment, a large ES was found in measuring functional impairment, and a medium ES was found in the other indicators. Conclusion The researchers provided evidence for the effectiveness of ACT as an intervention for patients with chronic pain, which can be applied by clinicians or nurses in practice. Future research should explore the applicability of ACT to different pain conditions and modalities. Implications for nursing Post-treatment data highlight the efficacy of ACT in moderating pain-related outcomes. Clinical nurses are encouraged to incorporate ACT into routine patient education and interventions, including promoting pain acceptance, promoting mindfulness practices, and using cognitive stress reduction techniques. Standardized follow-up after an ACT intervention for patients with chronic pain is critical, including regular assessment, feedback, and realignment of treatment strategies. Overall, ACT became an important tool for nurses to improve the lives of patients with chronic pain.
A thermo-responsive cellulose-based material (cellulose-
-PNIPAAm) was prepared by grafting
-isopropylacrylamide (NIPAAm) onto bagasse pulp cellulose via Ce (IV)-initiated free radical ...polymerization. The surfaces of the obtained cellulose-
-PNIPAAm paper showed a rapid wettability conversion from being hydrophilic (water contact angles (WCA) of 0°) at 25 °C to becoming hydrophobic (WCA of 134.2°) at 45 °C. Furthermore, the thermo-responsive mechanism of cellulose-
-PNIPAAm was examined by the in situ variable-temperature
C NMR, ¹H NMR and AFM analysis. At the same time, the resulting cellulose paper was applied for a switchable separation of oil/water mixtures. Water can pass through the paper under 45 °C, while oil is kept on the paper. When the temperature is above 45 °C, oil can permeate through the paper, while water cannot pass through the water. Moreover, the paper exhibited excellent regeneration performance after five cycles and maintained its switchable wettability.
This paper deals with the counterbalancing speed control issue of the closed hydrostatic drive hydraulic system of the heavy transportation vehicle under long down-slope. First, a novel method to ...realize the balancing to the down-slope weight force and the regulation to the motor speed is proposed. Next, a global fast terminal sliding mode control method is introduced to the speed control system. Then, addressing the load torque disturbance, a disturbance observer is designed for rejecting to disturbance. Finally, a test rig is established for verifying the effectiveness of the control method. The simulation and experimental results show that the designed continued hydraulic counterbalancing speed control system can smoothly regulate the traveling speed and restrain the load disturbance.
In this letter, a robust hybrid carrier frequency offset (CFO) estimation scheme based on training symbols is devised for universal-filtered multi-carrier (UFMC) based systems. In this scheme, the ...CFO estimator based on a least square (LS) criterion is first derived to acquire a coarse frequency offset estimation with the use of a large frequency searching step. And then, the residual frequency offset is accurately estimated through the auto-correlation operation of received signals, which have been compensated. This algorithm has the features of larger estimation range as well as higher estimation precision. Through numerical simulations, it is validated that the performance of the proposed algorithm is better than that of existing algorithms.
Improving the utilization of metals in heterogeneous catalysts with excellent catalytic performance, high selectivity and good stability represents a major challenge. Herein a new strategy is ...disclosed by enabling a nanoscale synergy between a transition metal and a noble metal. A novel Ru/Ni/Ni(OH)2/C catalyst, which is a hybrid of Ru nanoclusters anchored on Ni/Ni(OH)2 nanoparticles (NPs), was designed, prepared and characterized. The Ru/Ni/Ni(OH)2/C catalyst exhibited a remarkable catalytic activity for naphthalene hydrogenation in comparison with existing Ru/C, Ni/Ni(OH)2/C and Ru-Ni alloy/C catalysts. This is mainly attributed to the interfacial Ru, Ni and Ni(OH)2 sites of Ru/Ni/Ni(OH)2/C, where hydrogen is adsorbed and activated on Ru while Ni transfers the activated hydrogen species (as a "bridge") to the activated naphthalene on Ni(OH)2 sites, producing decalin through a highly effective pathway.
This paper deals with the robust control method for permanent magnet synchronous motor (PMSM) speed-regulation system based on active disturbance compensation. Different from the classical PMSM ...disturbance compensation scheme, a novel disturbance feed-forward compensation based on extended state observer (ESO) is designed for speed loop and q-axis current loop of PMSM. The disturbances of current loop include unmodeled dynamics of back electromotive force and parameters variations of stator are considered as lumped disturbance to compensate actively. In this way, the dynamic response of q-axis current loop can be improved to guarantee the anti-disturbance ability. A composite controller using sliding mode control and ESO is designed as speed loop controller, and an ESO-based proportional-integral controller is designed for q-axis current loop. Moreover, a transition process of reference signal is introduced to replace the step reference signal, which reduces the initial error and increases the range of feedback gain to improve system robustness. Finally, simulations and experiments are given to demonstrate the effectiveness of the proposed strategy.
Mining shovel is a crucial piece of equipment for high-efficiency production in open-pit mining and stands as one of the largest energy consumption sources in mining. However, substantial energy ...waste occurs during the descent of the hoisting system or the deceleration of the slewing platform. To reduce the energy loss, an innovative hydraulic-electric hybrid drive system is proposed, in which a hydraulic pump/motor connected with an accumulator is added to assist the electric motor to drive the hoisting system or slewing platform, recycling kinetic and potential energy. The utilization of the kinetic and potential energy reduces the energy loss and installed power of the mining shovel. Meanwhile, the reliability of the mining shovel pure electric drive system also can be increased. In this paper, the hydraulic-electric hybrid driving principle is introduced, a small-scale testbed is set up to verify the feasibility of the system, and a co-simulation model of the proposed system is established to clarify the system operation and energy characteristics. The test and simulation results show that, by adopting the proposed system, compared with the traditional purely electric driving system, the peak power and energy consumption of the hoisting electric motor are reduced by 36.7% and 29.7%, respectively. Similarly, the slewing electric motor experiences a significant decrease in peak power by 86.9% and a reduction in energy consumption by 59.4%. The proposed system expands the application area of the hydraulic electric hybrid drive system and provides a reference for its application in oversized and super heavy equipment.
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