Performance Testing and Analysis of Synchronous Reluctance Motor Utilizing Dual-phase Magnetic Material

While interior permanent magnet (1PM) machines have been considered the state-of-the art for traction motors, synchronous reluctance (SynRel) motors with advanced materials can provide a competitive alternative. 1PM machines typically utilize Neodymium 1ron Boron (NdFeB) permanent magnets, which pose an issue in terms of price, sustainability, demagnetization at higher operating temperatures, and uncontrolled generation. On the other hand, SynRel machines do not contain any magnets and are free from these issues. However, the absence of magnets as well the presence of bridges and centerposts limit the flux-weakening capability of a SynRel machine and limit the achievable constant power speed ratio (CPSR) without having to significantly oversize the machine and/or the power converter. 1n this paper, a new material referred to as the dual-phase magnetic material where nonmagnetic regions can be selectively introduced within each lamination will be evaluated for SynRel designs. The dual-phase feature of this material enables non-magnetic bridges and posts, eliminating one of the key limitations of the SynRel designs in terms of torque density and flux-weakening. This paper will present, the design, analysis and test results of an advanced proof-of-concept SynRel design utilizing dual-phase material with traction applications as the ultimate target application

Generalized Approach of Stator Shifting in Interior Permanent-Magnet Machines Equipped with Fractional-Slot Concentrated Windings

Electrical drive systems, which include electrical machines and power electronics, are a key enabling technology for advanced vehicle propulsion systems that reduce the petroleum dependence of the ground transportation sector. To have significant effect, electric drive technologies must be economical in terms of cost, weight, and size while meeting performance and reliability expectations. Interior permanent magnet machines with fractional-slot concentrated windings have been shown to be good candidates for hybrid traction applications. One of the key challenges is the additional stator magnetomotive force sub- and superharmonic components that lead to higher losses in the rotor as well as saturation effects. This paper tries to address this issue by looking into the concept of stator shifting. The generalized concept of stator shifting in the context of the harmonic components that are targeted for cancellation is presented; the focus is on single-layer and double-layer windings that have stator space subharmonics. It is shown that the stator shifting can reduce the loss-producing harmonics on the rotor as well as help the flux weakening performance of the fractional-slot concentrated winding designs. The cancellation of the loss harmonics is introduced as a method in which a particular harmonic can be targeted as well as reduce the phase inductance of the machine allowing for more room in terms of the operating voltage at higher speed. The concept of stator shifting will be explained, and the effect of varying the shift angle on the various harmonic components and winding factors will be investigated. Various designs, arising out of single-layer and double winding layer 10-pole, 12-slot configuration (targeting the FreedomCAR specifications) with varied shift angles are evaluated. The comparison between these designs in terms of their power density, efficiency, and torque ripple is presented

A novel method for initial rotor position estimation for IPM synchronous machine drives

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Testing of advanced permanent magnet machines for a wide range of applications

Permanent magnet machines are widely used across a wide range of applications. One of the key challenges is that there are no well-established standards for testing PM machines similar to those used for testing induction machines and wound-field synchronous machines. This paper will provide an overview of the key tests that need to be performed in order to fully quantify the PM machine performance. The paper also provides an overview of three distinct applications of advanced permanent magnet machine technologies. It describes the specific application benefits that are accomplished with permanent magnet solutions for automotive, and Oil & Gas. The details of the technology development for these three first-of-a-kind machines have been previously presented in other publications showing that each of which advances the state of the art in power density, torque density, or speed. The focus of this paper is the various tests that were performed on each of these machines as well as the test results. © 2012 IEEE

Global DNA Methylation in the Chestnut Blight Fungus Cryphonectria parasitica and Genome-Wide Changes in DNA Methylation Accompanied with Sectorization

Mutation in CpBck1, an ortholog of the cell wall integrity mitogen-activated protein kinase kinase kinase (MAPKKK) of Saccharomyces cerevisiae, in the chestnut blight fungus Cryphonectria parasitica resulted in a sporadic sectorization as culture proceeded. The progeny from the sectored area maintained the characteristics of the sector, showing a massive morphogenetic change, including robust mycelial growth without differentiation. Epigenetic changes were investigated as the genetic mechanism underlying this sectorization. Quantification of DNA methylation and whole-genome bisulfite sequencing revealed genome-wide DNA methylation of the wild-type at each nucleotide level and changes in DNA methylation of the sectored progeny. Compared to the wild-type, the sectored progeny exhibited marked genome-wide DNA hypomethylation but increased methylation sites. Expression analysis of two DNA methyltransferases, including two representative types of DNA methyltransferase (DNMTase), demonstrated that both were significantly down-regulated in the sectored progeny. However, functional analysis using mutant phenotypes of corresponding DNMTases demonstrated that a mutant of CpDmt1, an ortholog of RID of Neurospora crassa, resulted in the sectored phenotype but the CpDmt2 mutant did not, suggesting that the genetic basis of fungal sectorization is more complex. The present study revealed that a mutation in a signaling pathway component resulted in sectorization accompanied with changes in genome-wide DNA methylation, which suggests that this signal transduction pathway is important for epigenetic control of sectorization via regulation of genes involved in DNA methylation