Xia S.-X.,Zhejiang Industry & Trade Vocational College
Tien Tzu Hsueh Pao/Acta Electronica Sinica | Year: 2015
The paper proposes a new three-phase four-wire multilevel inverter. Besides the conventional six-switch three-phase full-bridge inverter output, the inverter cascades to a half bridge configuration and has a bootstrap circuit with the load neutral line connecting to the anode of input power. Under the ripple-tracing segmental SPWM(Sinusoidal Pulse Width Modulation), the cascaded half-bridge electricity is obtained when the bootstrap circuit works. The circuit topology structure and its control method reduce the independent direct-current power sources of the multilevel inverter and raise the inverter output voltage. Using the piecewise calculation method, the paper analyzes the ripples and current of the bootstrap capacitor with regular sampling SPWM modulation, and the harmonic waves generated. The analyses and experiments in this paper show that a bootstrap capacitor's capacitance, charging loop resistance, load and modulation degree can affect the capacitor's ripples and current. ©, 2015, Chinese Institute of Electronics. All right reserved.
Xia S.,Zhejiang Industry & Trade Vocational College
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | Year: 2015
A new five-level half-bridge cascaded Inverter is presented. It is derived from the traditional H-Bridge by cascading the first-level half-bridge on the two half-bridges and connecting the bootstrap components between the upper and lower cascades. By using the CPS-SPWM, the bootstrap circuit will supply the power for the cascaded half-bridge, and it is not need independent DC power supply, which raises the output voltage of the inverter. On the applications of the inversion of the solar cell, storage cell, super-capacitor and other DC power supplies, the new inverter will decrease the amounts of the cells in series of the power branch. The effect of the load, modulation index, electric resistance of charge circuit and the capacity of the bootstrap electric capacitor on the ripple voltage the bootstrap electric capacitor, charging current and output harmonic wave of the inverter is analyzed by using infinitesimal method. By further analysis and experiments, we verify that it is the multilevel inverter is verified to be a kind of inverter with high voltage utilization and less voltage requirements. ©, 2015, Science Press. All right reserved.
Lin J.-X.,Zhejiang Industry & Trade Vocational College |
Lin J.-X.,Jilin University |
Tong X.,Zhejiang Industry & Trade Vocational College |
Liu C.-M.,Zhejiang Industry & Trade Vocational College |
And 3 more authors.
Zhuzao/Foundry | Year: 2015
Through designing a group of L9(34) orthogonal experiment, microstructure and mechanical properties of alloy with adding different metal elements contents were analyzed, the optimal composition proportion of high strength near eutectic Al-11.6Si-3Cu alloy was determined. The results show that the best process parameter of intuitive analysis is A2B1C3D3 which the adding content of the alloy is (wt.%):0.3%Mg, 0.4% Zn, 0.3% Sb and 0.25% Ti. Variance analysis shows that factor D (addition of Ti) has an significant influence, while A, B, C (addition of Mg, Zn and Sb) have some certain effects, the extent of influence of these four factors on the tensile strength is D>A>C>B; with the process parameter of A2B1C3D2, the tensile strength of alloy was 304.9 MPa. ©, 2015, Chinese Mechanical Engineering Society. All right reserved.
Zhang J.,Wenzhou Vocational & Technical College |
Zhang J.,Zhejiang Industry & Trade Vocational College |
Shi K.,Huazhong University of Science and Technology
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2015
An autonomous shop floor control system based on wireless sensor network was proposed to cope with the unforeseen inside and outside disturbances occurring frequently. In this system, the physical objects such as the parts and machines were enriched with competencies and abilities for communicating, computing and decision-making by sensor nodes embedding. A pheromone based control algorithm that imitated ants foraging behavior was developed to make the parts autonomously deciding efficient processing operations and routing paths. To demonstrate the feasibility and advantages of the proposed control system, a prototype implementation was developed, and experiments were made with this prototype implementation. The experimental results illustrate the advantages of the proposed approach and its capacity to surmount perturbations. ©, 2015, China Mechanical Engineering Magazine Office. All right reserved.
Gao Y.,Zhejiang Industry & Trade Vocational College |
Fu Q.,Sichuan University |
Niu L.,Zhejiang Industry & Trade Vocational College |
Shi Z.,Zhejiang Industry & Trade Vocational College
Journal of Materials Science | Year: 2015
The interfacial adhesion is a significant factor for improving mechanical properties of filler-reinforced polymer composites. In this work, the as-spun and hot-stretched poly(phenylene sulfide) (PPS) and multi-walled carbon nanotubes (MWCNTs) composite fibers were prepared. Tensile test showed that large enhancements in tensile strength and modulus were achieved in hot-stretched samples. The strong interfacial interaction leading to the effective load transferring was realized in hot-stretched composite fibers. Further analysis showed that the strong interfacial adhesion might be the result of the formation of π–π interaction between the benzene ring of PPS and the surface of MWCNTs with the help of hot-stretching, which could be the most important reason for the remarkable mechanical enhancement of the hot-stretched composite fibers. © 2015, Springer Science+Business Media New York.