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The torque performance of permanent magnet synchronous motors (PMSMs), especially the torque output capacity and torque pulsation, which have a significant impact on their efficiency and capabilities. In this article, a novel hybrid rotor structure and improved Taguchi optimization design based on the fuzzy theory for PMSM torque performance enhancement are proposed. First, surface and interior magnet poles are combined to propose a new surface and interior hybrid PMSM (SIHPMSM), which adopts the Halbach array and U-shaped permanent magnets, respectively. In particular, an unevenly segmented and different eccentricity Halbach arrays is applied to optimize magnetic field performance. Second, the comparative analysis of typical rotor topologies is conducted, whose corresponding results indicate that SIHPMSM exhibits better electromagnetic properties. In addition, five essential variables are analyzed to further explore the affects of different parameters on the torque characteristics in SIHPMSM. Finally, on the basis of the Taguchi method and fuzzy theory, an improved optimization scheme is proposed, which can resolve the deficiencies of the traditional Taguchi method in multiobjective optimization. Several targets including torque and torque ripple are standardized by introducing the multiple performance characteristics index (MPCI). The final optimization results significantly improve the torque output performance while reducing the torque pulsations.

This paper is concerned with the problem of robust observer-based finite-time H∞control for discrete-time singular Markovian jumping system with time-varying delay and actuator saturation. By using linear matrix inequality (LMI) approach and constructing proper Lyapunov–Krasovskii functional, sufficient criteria have been obtained that ensure the system singular stochastic finite-time boundedness and singular stochastic finite-time H∞boundedness. Then the observer and feedback controllers are designed, and with the following the results are extended to convex optimization problems so that the optimal values of attenuation level and the maximum saturation attraction domain can be calculated directly. In the end, some numerical examples are presented to show the feasibility and validity of the proposed results.

This paper focus on the problem of observer-based $$H_{\infty }$$ H∞ control for uncertain nonlinear Markovian jump systems with time-delay and actuator saturation. A delay-dependent sufficient condition is proposed which guarantees that the uncertain nonlinear Markovian jump system with time-delay and input saturation is stochastically stable via Lyapunov theory and linear matrix inequality (LMI) approach. Then, with this condition, the estimation of stability region and the design method of observer-based $$H_{\infty }$$ H∞ controller are given by solving LMIs and convex optimization problems. Finally, numerical examples are exploited to illustrate the effectiveness of the proposed method.

We have demonstrated in this article that both power conversion efficiency (PCE) and performance stability of inverted planar heterojunction perovskite solar cells can be improved by using a ZnO:PFN nanocomposite (PFN: poly[(9,9-bis(3′-(N,N-dimethylamion)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctyl)-fluorene]) as the cathode buffer layer (CBL). This nanocomposite could form a compact and defect-less CBL film on the perovskite/PC61BM surface (PC61BM: phenyl-C61-butyric acid methyl ester). In addition, the high conductivity of the nanocomposite layer makes it works well at a layer thickness of 150 nm. Both advantages of the composite layer are helpful in reducing interface charge recombination and improving device performance. The power conversion efficiency (PCE) of the best ZnO:PFN CBL based device was measured to be 12.76%, which is higher than that of device without CBL (9.00%), or device with ZnO (7.93%) or PFN (11.30%) as the cathode buffer layer. In addition, the long-term stability is improved by using ZnO:PFN composite cathode buffer layer when compare to that of the reference cells. Almost no degradation of open circuit voltage (VOC) and fill factor (FF) was found for the device having ZnO:PFN, suggesting that ZnO:PFN is able to stabilize the interface property and consequently improve the solar cell performance stability.