Zero-sequence Current Suppressing Strategy for Dual Three-phase Permanent Magnet Synchronous Machines Connected with Single Neutral Point

Dual three-phase permanent-magnet synchronous machines(DTP-PMSM)connected with a single neutral point provide a loop for zero-sequence current(ZSC).This paper proposes a novel space vector pulse width modulation(SVPWM)strategy to suppress the ZSC.Five vectors are selected as basic voltage vectors in one switching period.The fundamental and harmonic planes and the zero-sequence plane are taken into consideration to synthesis the reference voltage vector.To suppress the ZSC,a non-zero zero-sequence voltage(ZSV)is generated to compensate the third harmonic back-EMF.Rather than triangular carrier modulation,the sawtooth carrier modulation strategy is used to generate asymmetric PWM signals.The modulation range is investigated to explore the variation of modulation range caused by considering the zero-sequence plane.With the proposed method,the ZSC can be considerably reduced.The simulated and experimental results are presented to validate the effectiveness of the proposed modulation strategy.

Organoboron chemistry towards controlled and precise polymer synthesis

Organoboron reagents have garnered considerable attention due to their distinct properties. In recent years, boronic acids and boronate esters have been important intermediates for cross-coupling reactions and other functional group construction and are often used to synthesize small organic molecules, drugs, and bioactive substances. In this feature article, we encapsulate the strategy of harnessing the unique properties of organoboron reagents to overcome challenges encountered in conventional polymer synthesis. We delve into the synthesis of boron-containing monomers and polymer materials, unraveling the unique attributes of these newfound polymers while offering innovative insights into their application within recyclable or reprocessable materials. We develop organoboron-based photocatalysts, employing their inner-sphere electron transfer(ISET) mechanisms to initiate controlled radical polymerization. We utilize alkylborane to initiate controlled radical polymerization and further designed B-alkylcatecholboranes to prepare ultra-high molecular weight polymers. Notably, we also propose a liquid-phase synthesis method based on organoboron tags and apply it to the precise synthesis of sequence-controlled conjugated polymers.These advancements open up new frontiers in the realm of polymer science, and the versatility and potential of organoboron reagents in polymer synthesis continue to inspire exciting research endeavors.