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Proton exchange membrane fuel cell (PEMFC) is a new type of fuel cell developed after alkaline fuel cell, phosphoric acid fuel cell, molten carbonate fuel cell and solid oxide fuel cell. In this paper, the dynamic parameter model of PEMFC electric reactor is established based on the experience of proton exchange membrane fuel cells. On the basis of this parameter model, the intelligent method is used to identify the system, and the identification model of voltage and temperature is established. Finally, based on fuzzy logic, the operating performance of the battery system was simulated, a comprehensive PEMFC simulation model was established, a PEMFC voltage identification model was established, and a PEMFC temperature identification model was established by using fuzzy logic network, so as to reduce the fluctuation range as much as possible to reach the research purpose.

With the dramatic requirements of high power and high integrity in field of power devices, the study of novel interconnection materials and packaging methods has been paid an extremely attention. Presently, the most candidates for the chip bonding are Zn-based, Bi-based, noble-metal-based (such as Au-Sn, Au-Ge, Au-Si), nano-metal particles (Ag or Cu nanoparticles) and transient-liquid-phase (TLP) bonding. However, a high bonding temperature and poor ductility for Zn-based solder (more than 420°C) causing irreversible damages or accelerated aging affects to the electronic devices; Bi-based solder alloys are still under way mainly due to their inferior thermal and electrical conductivity as well as poor workability; It's worth noting that nano-silver sintering and TLP bonding technology have been proven to be the potential solutions to the power electronic packaging, because their processing temperatures are relatively low and the produced joints are of high re-melting temperatures. However, Ag is expensive and easy to electromigration, which will influence the stability/reliability of the joints and hinder to universal industry applications. For the TLP bonding, the process to produce full intermetallic compounds (IMCs) is time-consuming, commonly more than 60 min, due to relatively low reaction velocity. To solve the problem of time-consuming of the TLP, an enhanced and low-cost auxiliary energy is necessary. Ultrasonic-assisted soldering has been proven able to solder dissimilar metals at low temperatures within a very short time. In our previous work, a full Cu6Sn5/Cu3Sn IMCs joint through TLP assisted by ultrasound was obtained. Because of the acoustic cavitation and streaming effect created by ultrasonic waves propagating in molten alloys, the atom diffusion and physical-chemical interactions were accelerated at the liquid/solid interfaces. However, a sole IMC joint with single phase has not been fabricated so far. High re-melting temperature joint consisted of nearly sole Ni 3 Sn 4 with a high shear strength of 43.4 MPa was achieved with Sn-24 wt.%Ni by ultrasonic-assisted soldering for 10 s. This rapidly formed intermetallic joint was phase-stable as isothermally aged at 300 °C for 72 h in air and its shear strength was 33.4 MPa due to the Ni 3 Sn 4 grains coarsening. These results demonstrate that the less time-consuming ultrasonic-assisted soldering has wide potentials for high-temperature power electronic packaging.

The maintenance integration information model is the basis of maintenance simulation, maintenance process plan and maintenance data management. A product maintenance integration model is put forward by integrating product 3D solid model and attribute file in this paper. The product maintenance integration model is composed of geometry feature, precision feature, assembly relation feature, heat treatment feature, management feature, maintenance feature etc. All these features are modeled using UML C++ class diagram and realized into the attribute file. The knowledge on product fault diagnosis and handling, disassembly/assembly of maintenance object is also encapsulated in the maintenance unit of product maintenance object. The steam turbine rotor maintenance integration model is realized on the basis of solidworks platform by using Visual C++ 6.0 and SQL server2000 at last.