In this paper, the distributed power flow controller which belongs to the new generation of flexible AC transmission equipment is briefly introduced. The extended equal area criterion is used to study the transient stability of the distributed power flow controller, and the influences of the distributed power flow controller on the extended equal area criterion are analyzed. The equivalent model of the distributed power flow controller is built on the ADPSS software platform. The simulation results verify that this equivalent model is adaptable to extended equal area criterion method. And the method can be used to analysis distributed power flow controller's transient stability.
Surface/neuron interfaces have played an important role in neural repair including neural prostheses and tissue engineered scaffolds. This comprehensive literature review covers recent studies on the modification of surface/neuron interfaces. These interfaces are identified in cases both where the surfaces of substrates or scaffolds were in direct contact with cells and where the surfaces were modified to facilitate cell adhesion and controlling cell-type specific responses. Different sources of cells for neural repair are described, such as pheochromocytoma neuronal-like cell, neural stem cell (NSC), embryonic stem cell (ESC), mesenchymal stem cell (MSC) and induced pluripotent stem cell (iPS). Commonly modified methods are discussed including patterned surfaces at micro- or nano-scale, surface modification with conducting coatings, and functionalized surfaces with immobilized bioactive molecules. These approaches to control cell-type specific responses have enormous potential implications in neural repair.
As the basic units of electronic systems, electronic module is essential for the normal operation of the electronic system. The method to stimulate the failure of electronic modules, locate the weak parts and optimize the modules, is the concern for both of the industry and academia. Taking a power module as an example, this paper provides a new method to accurately locate the weak parts of electronic modules and improve the design of the module, which helps to find out the exact point of the fault and optimize the design of the module. First, use the high-acceleration vibration chamber, QualMark Typhoon 2.5, to carry out random vibration test on the power module, recording the output signal changes in real time, which helps to determine whether the power supply module has failed. Then, build the finite element simulation model of the power module and carry out random vibration simulation to obtain the stress distribution. According to the actual fault state and the circuit simulation of the power module, determine the weak parts of the module and verify the analysis results by the physical failure injection test. Finally, analyze the effects of different shapes of solder joint and solder dosage on the stress distribution and anti-vibration performance of power module's weak parts. And give an optimization scheme to improve its reliability under vibration stress.
Severe heat generation in power electronic devices is often the biggest culprit in harming their reliability. Our work analyses the heat loss composition and numerically calculates each component's loss for SiC MOSFETs, a vital heat-generating device in SSPCs. After that, we built a thermal simulation model of the whole SSPC in the finite element simulation software Ansys Icepak. After Considering the interactive effects of temperature and device heat generation, accurate steady-state thermal simulation results are obtained. The results obtained will contribute to the better design of reliability.
There are various challenges in designing a life-cycle robust permanent magnet actuator (PMA) to satisfy the application-oriented requirements of quality consistency. In particular, ubiquitous uncertainties from manufacturing and operating process that cause unstable or even infeasible solutions significantly increase the difficulty of the life-cycle robust design of PMA. Conventional methods usually treated these uncertainties as fixed design constraints, which neglect the nonlinear characteristic of time-dependent degradations, cannot reflect authentic impacts on the life-cycle robustness of PMA. To address this issue, this study propose a method of life-cycle dynamic robust design optimization for batch production PMA. An innovative time-dependent global sensitivity analysis-based classification method is first proposed to divide design variables into three categories: nonlinear, degradation insensitive, and degradation sensitive variables. Then, a modified Spatiotemporal Kriging model with Karhunen-Loeve expansion is applied to establish the life-cycle robustness model of PMA with consideration of uncertainties. This model can valid describe the nonlinear fluctuation of the life-cycle robustness. Furthermore, on the basis of the three categories of design variables and life-cycle robustness model, a multistage dynamic robust design optimization strategy is derived, which realizes the synchronous control of life-cycle robustness deterioration rate (mean value) and fluctuation (standard deviation). Finally, taking a case of rotary PMA, the effectiveness of the proposed method is verified.
This paper presents a 6-bit phase shifter with a low root-mean-square (RMS) phase error and a flat gain across 1.9-2.6GHz. An input balun which utilizes a differential signal correction system consisting of two capacitor-cross-coupled (CCC) pairs and one CCC buffer is realized to ensure good phase and amplitude balance. Based on the relationship of the W/L of DAC cells, an encode rule which makes the 6-bit input generate eight DAC code is presented. A gain compensation technique is employed to realize a flat overall gain in the range of 1.9-2.6GHz. In 0.18-μm CMOS technology, the simulation results illustrate that the proposed phase shifter achieves less than 0.635 degree RMS phase error and less than 0.6dB gain variation across 1.9-2.6GHz.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)