Interplane cross-saturation in multiphase machines

The use of electrical machines in electric vehicles and high-power drives frequently requires multiphase machines and multiphase inverters. While appropriate mathematical models under the linear magnetic conditions are readily available for multiphase machines, the same cannot be said for the models of the saturated multiphase machines. This paper examines the saturation in an asymmetrical six-phase induction machine under different supply conditions and addresses the applicability of the existing saturated three-phase machine models for representation of saturated multiphase machines. Specifically, the mutual coupling between different sequence planes in the vector space decomposed model under saturated conditions is analyzed. The paper relies on analytical considerations, finite element analysis and experimental results. It is shown that the saturation of the main flux path is influenced by the current components in the orthogonal (non-fundamental) sequence plane. This implies the need to develop new multiphase machine models which take this effect into account

ETUDE ELECTROCHIMIQUE DE L’INHIBITION DU PROCEDE D’ENTARTRAGE DANS UNE EAU DE MER

Calcareous scaling on domestic and industrial equipments generates severe problems and causes drastic economic loss. The use of several chemicals is a common technique to impede the scale deposition. The subject of this study is the inhibition of the scaling process. Thus, we have followed the coverage of a titanium electrode, in absence and in presence of two anti-scale products, using the chronoamperometry. The mineral scales were characterized by electrochemical impedance spectroscopy (EIS) and analyzed by electronic sweeping microscopy (ESM). It was found that 25 ppm of hydroxyl-2 méthyl-4 benzylphosponic acide (AHMBP) or of Diprochim anti-scale is sufficient to prevent electrodeposition. The efficiency of the two chemicals is comparable.L’entartrage des installations domestiques ou industrielles cause de sévères problèmes techniques et économiques. La technique la plus courante utilisée pour ralentir cette déposition consiste à utiliser divers inhibiteurs chimiques. L’objectif de cette étude rentre dans ce cadre. En effet, nous avons suivi par chronoampérométrie, l’évolution du recouvrement d’une électrode en titane, en absence et en présence de deux inhibiteurs d’entartrage. Les dépôts formés sont caractérisés par la spectroscopie d’impédance électrochimique (SIE) et analysés par microscopie électronique à balayage (MEB). 25 ppm de l’acide hydroxy-2 méthyl-4 benzylphosponique (AHMBP) ou de l’antitartre Diprochim suffisent pour ralentir considérablement le recouvrement de l’électrode. L’efficacité des deux inhibiteurs utilisés est comparable

New Space Vector Selection Scheme for VSI Supplied Dual Three-Phase Induction Machine

This paper presents a novel space vector selection scheme applicable for the control of dual three-phase induction motor drives supplied from a six-phase voltage source inverter (VSI). The vector selection method is based on the vector space decomposition technique (VSD). Unique vector selection pattern simplifies problems related to complicated implementation of standard VSD in commercially available digital signals processors (DSP). The proposed vector selection scheme is verified through a theoretical analysis, computer simulations and practical experimental results conducted on a dual three-phase test rig prototype with control algorithm implemented in Texas Instrument?s TMS320F2808 DSP

Optimization of optical properties of high chiral planar waveguides obtained by sol–gel method

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Direct Torque Control with Full Order Stator Flux Observer for Dual-Three Phase Induction Motor Drives

A Direct Torque Control (DTC) strategy for dual-three phase induction motor drives is discussed in this paper. The induction machine has two sets of stator three-phase windings spatially shifted by 30 electrical degrees with isolated neutral points. The proposed control strategy is based on Proportional Integral (PI) regulators implemented in the stator flux synchronous reference frame. To improve the flux estimation, an Adaptive Stator Flux Observer (ASFO) has been used. Doing so, besides a better flux estimation in contrast to open-loop flux estimators, it is possible to use the observed currents to compensate the inverter non-linear behavior (such as dead-time effects), improving the drive performance at low speed. This is particularly important for low voltage/high current applications, as the drive considered in this paper. The advantages of the discussed control strategy are: constant inverter switching frequency, good transient and steady-state performance and less distorted machine currents in contrast to DTC schemes with variable switching frequency. Experimental results are presented for a 10kW dual three-phase induction motor drive prototyp