Modelling of the permanent magnet synchronous motor (PMSM) torque ripple and PMSM current harmonics controlling technology are important branches of PMSM research. Based on the existing linear PMSM model derived from magnetic co-energy, this study considers the variation of PMSM parameters (inductance, permanent magnet flux and cogging torque) caused by magnetic saturation. Then, the harmonic coupling models including flux-current coupling model, voltagecurrent coupling model and torque-current coupling model are deduced. In these harmonic coupling models, the PMSM parameters no longer vary with rotor position but only with current amplitude and phase. Based on the torque-current coupling model, a novel method of obtaining the required injecting currents which could suppress torque ripple is proposed. The validity of the harmonic coupling models and the injecting current solution method is verified by finite-element method.
For mass production of hydrogen fuel by electrochemical water splitting, seawater is preferred because of its abundant reserves on Earth. However, the current seawater electrolysis technology is seriously hindered by the low selectivity and poor stability of oxygen evolution reaction (OER) at anode due to undesirable chloride electrochemistry and severe corrosion in practical application. Herein, based on the "work function optimization" concept, vein-like Crdoping Co x P is rationally designed as a highly-efficient OER electrocatalyst for direct seawater electrolysis, achieving current densities of 20 and 100 mA cm -2 at overpotentials of 268 and 325 mV, respectively, together with high OER selectivity and long-term stability. Experimental data and theoretical calculations reveal that the regulation of the electronic structure of Co x P induced by Cr doping strongly alleviates the work function of Co x P, which not only accelerates the electron transfer between the catalyst surface and the absorbates but also lowers the energy barriers of water dissociation and rate-determining step for both OER and hydrogen evolution reaction (HER). Moreover, Cr doping also protects the Co sites with robust valence states to maintain their high performance during the OER process, providing a new avenue to design non-noble metal-based catalysts for hydrogen generation from seawater electrolysis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.