Abstract-This paper proposes a comprehensive framework for multiobjective design optimization of switched reluctance motors (SRMs) based on a combination of the design of experiments and particle swarm optimization (PSO) approaches. First, the definitive screening design was employed to perform sensitivity analyses to identify significant design variables without bias of interaction effects between design variables. Next, optimal third-order response surface (RS) models were constructed based on the Audze-Eglais Latin hypercube design using the selected significant design variables. The constructed optimal RS models consist of only significant regression terms, which were selected by using PSO. Then, a PSObased multiobjective optimization coupled with the constructed RS models, instead of the finite-element analysis, was performed to generate the Pareto front with a significantly reduced computational cost. A sample SRM design with multiple optimization objectives, i.e., maximizing torque per active mass, maximizing efficiency, and minimizing torque ripple, was conducted to verify the effectiveness of the proposed optimal design framework.Index Terms-Design of experiments (DoE), multiobjective optimization, particle swarm optimization (PSO), response surface (RS), sensitivity analysis, switched reluctance motor (SRM).

this paper proposes an adaptive dc-link voltage control method for the two-stage photovoltaic (PV) inverter during the low voltage ride-through (LVRT) operation period. The dc-link voltage will be controlled to follow the change of grid voltage during the low voltage ride-through operation to maintain the high modulation ratio so that the high frequency harmonics injected into the grid can be attenuated significantly. Besides, when suffering the asymmetrical grid faults, the proposed control method could to some extent attenuate the double-line-frequency dc-link voltage ripple to keep the dc-link voltage in the safe operational range by shifting the double-line-frequency power ripple to the front-end dc input source, which can be achieved by intentionally fluctuating the dc input power or employing a bi-directional dc-dc converter depending on the voltage drop ratio and the input power level. The theoretical findings were verified by Matlab simulations and the constructed experimental prototype.Index Terms-Low voltage ride-through, photovoltaic inverter, dc-link voltage, two-stage inverter. 1 0885-8993 (c)

This paper proposes a differential evolution (DE) optimization-based current profiling method for simultaneous reduction of the torque ripple and vibration of switched reluctance motors (SRMs). The mechanism of torque generation in SRMs produces radial forces in addition to the required tangential force. It has been shown that the radial forces acting on the stator are the main vibration source in SRMs and keeping the sum of the radial forces constant can reduce the magnitude of the significant harmonics of the sum of radial forces and further reduce vibration by avoiding the resonance caused by those harmonics. A simple method is proposed to model the torque and radial forces generated in the SRMs while considering the saturation effects. The resulting torque and radial force models are then used in the DE optimization process to generate the current profile of each phase in the form of Fourier series, where the Fourier coefficients of each phase current profile are determined to minimize the torque ripple and significant harmonics in the sum of the radial forces. The proposed method significantly reduces the computational cost of the finite element analysis (FEA)-based methods. The effectiveness of the proposed method is verified through both FEA simulation and experimental results.

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