Sensorless Control of Bearingless Permanent Magnet Synchronous Motor Based on LS-SVM Inverse System

In order to solve the problems of low integration, low reliability, and high cost caused by mechanical sensors used in bearingless permanent magnet synchronous motor (BPMSM) control systems, a novel speed and displacement sensorless control method using a least-squares support vector machine (LS-SVM) left inverse system is proposed in this paper. Firstly, the suspension force generation principle of the BPMSM is introduced, and the mathematical model of the BPMSM is derived. Secondly, the observation principle of the left inverse system is explained, and the left reversibility of the established speed and displacement subsystem is proved. Thirdly, the left inverse systems of the speed and displacement subsystems are constructed by using the LS-SVM, and the complete speed and displacement sensorless control system is constructed. Finally, the simulations and experiments of the proposed method are performed. The research results demonstrate that the proposed observation method can identify the speed and displacement quickly and accurately, and the sensorless control method can realize the stable operation of the BPMSM without speed and displacement sensors.

Čech systems and approximate inverse systems

We generalize a result of the first author who proved that the Čech system of open covers of a Hausdorff arc-like space cannot induce an approximate system of the nerves of these covers under any choices of the meshes and the projections.

On the nature of inverse systems

Previous theoretical discussion about inverse systems has largely revolved around the synchronic and diachronic relationship between the inverse and the passive. In contrast, this study argues for the antipassive origins of two inverse constructions in Monsang (Trans-Himalayan), which are used for 3→SAP and 2→1 scenarios. This questions central assumptions from previous accounts about the functional motivation underlying inverse systems, and suggests that strategies of avoiding overt reference may be at play. The diachronic pathway proposed here connects the traditional inverse with other special marking patterns that involve speech act participant objects, in particular the “pseudo-inverse” construction of innovative first person object indexation.

Quantitative towers in finite difference calculus approximating the continuum

Multivector fields and differential forms at the continuum level have respectively two commutative associative products, a third composition product between them and various operators like $\partial$, d and ‘*’ which are used to describe many nonlinear problems. The point of this paper is to construct consistent direct and inverse systems of finite dimensional approximations to these structures and to calculate combinatorially how these finite dimensional models differ from their continuum idealizations. In a Euclidean background, there is an explicit answer which is natural statistically.

Person in Morphology

The category of person is a linguistic expression of reference to a role in a speech act, including the speaker, the addressee, or a combination thereof. The values of the person category commonly, if not universally, include the opposition of first person (reference to the speaker) versus second person (reference to the addressee). Reference to neither the speaker nor the addressee is commonly—though not always—considered to be the third value of the category, third person. This article is an overview of person indexation on the verb and in possessive constructions, interaction of the category of person with other categories such as number and moods, the issue of person hierarchies as reflected in the categories of clusivity and direct-inverse systems, and some topics in the pragmatics of person. The discussion includes some topics disregarded or less touched upon in other surveys of the category of person, such as a discussion of the person relationship to commands (imperative paradigms) or logophoricity. The main focus is on the morphology of person, and other aspects of personal reference are discussed with respect to how they are expressed or differentiated by morphological material. On the other hand, personal reference in grammar and lexicon show strong affinity, making it both difficult and unnecessary to separate independent personal pronouns from person affixes in a typological perspective. In this sense, person-related lexicon and inflectional morphology are treated together.

Better constraining the CO2 plant uptake at global scale: joint assimilation of COS and CO2 atmospheric measurements into a transport model.

<p>Inverse systems that assimilate atmospheric carbon dioxide measurements (CO2) into a global atmospheric transport model, are commonly used together with anthropogenic emission inventories to infer net biospheric surface fluxes. However, when assimilating CO2 measurements only, the respiration fluxes cannot be disentangled from the gross primary production (GPP) fluxes, leaving few possibilities to interpret the inferred fluxes from a mechanistic point of view. Measurements of carbonyl sulfide (COS) may help to fill this gap: COS has similar diffusion pathway inside leaves as CO2 but is not re-emitted into the atmosphere by the plant respiration. We explore here the benefit of assimilating both COS and CO2 measurements into the LMDz atmospheric transport model to constrain GPP and respiration fluxes separately. To this end, we develop an analytic inverse system based on the 14 Plant functional Type (PFTs) as defined in the ORCHIDEE land surface model. The vegetation uptake of COS is parameterized as a linear function of GPP and of the leaf relative uptake (LRU), which is the ratio of COS to CO2 deposition velocities in plants. A new parameterization of the atmosphere soil exchanges is also included. We use the system to optimize GPP and respiration fluxes separately at the seasonal scale over the globe. The results lead to a balanced COS global budget and a seasonality of the COS fluxes in better agreement with observations. We find a large sensitivity of the partition between the ocean emissions and the COS plant uptake to the LRU parameterizations.</p>