Co-channel Interference Energy Harvesting for Decode-and-Forward Relaying

In this paper, co-channel interferences are exploited for energy harvesting in a Cooperative Network (CICN) in which a power constrained relay uses a power splitting architecture (CICN-PS) and a time switching architecture (CICN-TS) to harvest energy from the radio-frequency signals received from a source node and co-channel interferences. In the proposed CICN-PS and CICN-TS protocols, the relay applies decode-and-forward technology to decode the information of the source node, and then forwards the recoded information to a destination with the overall harvested energies. The system performance of the proposed protocols is discussed and evaluated using the exact throughput analyses and is then checked using Monte Carlo simulations over Rayleigh fading channels. The optimal power splitting ratio and energy harvesting time are derived by the Golden Section Search method, and throughput performance evaluations are performed. Our numerical and simulation results show distributions as follows. Firstly, the CICN-PS protocol outperforms the CICN-TS protocol. Secondly, the proposed protocols strictly depend on the location, amount and power of the co-channel interferences. Thirdly, when signal-to-noise ratio increases, the proposed CICN-PS protocol achieves the perfect throughputs where the cooperative relay applies the ideal receiver and co-channel interferences do not affect the destination. Finally, the numerical analyses agree well with the simulation results.     

A Novel Cogging Torque Reduction Method for Interior-Type Permanent-Magnet Motor

This paper presents a novel design method to reduce the cogging torque of interior-type permanent-magnet (PM) motor. In the design method, the optimal notches are put on the rotor pole face, which have an effect on the variation of PM shape or the residual flux density of PM. Through the space harmonic field analysis, the positions of notches are found, and the optimal shapes of notches are determined by using finite element method. The validity of the proposed method is confirmed by experiments.     

The fabrication of efficiency-improved W-series interconnect type of module by balancing the performance of single cells

Large dye-sensitized solar cells (DSCs) are usually fabricated as module types instead of single cell types, because the overall efficiency of an area-expanded single DSC is decreased by its large surface resistances and low fill factor (FF). The general DSC module designs are the parallel grid, series interconnect, and series monolithic types. The W-series interconnect type of module has some advantages, such as its easy fabrication and simple structure. Moreover, it also avoids the reduction in the FF. However, it has an efficiency imbalance between the single cells, because of the discrepancy in their luminous intensity. Therefore, the fabrication of the W-series interconnect type of module will be cost-effective only if the problem of its efficiency imbalance is solved. In this study, the thickness of the Pt layer, which has a very high reflection rate, and that of the electrolyte layer are minimized and the transmitted light is reflected by a metallic thin film in order to increase the number of photons absorbed by the dye molecules in the module. As a result, the performance of the efficiency-balanced W-module is improved by approximately 1% as compared to that of the conventional module.