Control loop for finding initial translator position of linear synchronous motor

This article presents a simple and reliable method for controlling the relative orientation between the two magnetic fields of a permanent magnet synchronous motor. Finding the initial (at motor powering- up time) value of this relative location is essential for the proper operation of the motor. After showing the system controllability, the utilized feedback control loop finds this initial relative orientation quickly and accurately. Further, using the proposed method allows considerable cost saving, as a transducer that is usually used for this purpose can be eliminated. The cost saving is most obvious in the case of linear motors and angle motors with large diameters. The way the problem is posed is an essential part of this work, and it is the reason behind the apparent simplicity of the solution. The method proposed relies on a single sensor, and it was tested when a relative encoder was used.

Controlling the relative orientation between the two magnetic fields of a synchronous motor

A simple and reliable method for controlling the relative orientation between the two magnetic fields of a permanent magnet synchronous motor is presented. Finding the initial (at motor powering-up time) value of this relative location is essential for the proper operation of the motor. The feedback control loop used finds this initial relative orientation quickly. Further, using the proposed method allows considerable cost saving, as a transducer that is usually used for this purpose can be eliminated. The cost saving is most obvious in the case of linear motors and angle motors with large diameters. The way the problem is posed is an essential part of this work and it is the reason behind the apparent simplicity of the solution. The method relied upon a single sensor, and it has been tested when a relative encoder was used

Effect of hydrogen/air flow rates and scan rate on the flame ionisation detection response of phopholipids, and their quantitative and qualitative analysis by Iatroscan (Mark‐6s) TLC‐FID

The combined effect of scan speed, hydrogen and air flow rates on the flame ionization detection (FID) peak response of phospholipid classes has been studied to determine the optimum levels of these parameters. The phospholipid composition of different types of commercial lecithins, as well as lecithins combined with fish oils, has been analyzed by Iatroscan TLC‐FID Mark‐6s under optimized conditions. An air flow rate of 2 L/min, a hydrogen flow rate of 150–160 mL/min, and a scan speed of 30 s/rod seem to be the ideal conditions for scanning phospholipids with complete pyrolysis in the flame in the Mark‐6 model. Increasing the scan speed rapidly decreased the FID response. A hydrogen flow rate as high as 170 mL/min could be used at relatively low air flow rates (&#x003C2 L/min) and the response declined when both air flow rate and hydrogen flow rate increased simultaneously. Both linear and curvilinear relationships had highly significant correlations (p&#x003C0.01) with the sample load. Time course reactions, including the hydrolysis of phosphatidylserine using enzymes, can be successfully monitored by the Iatroscan TLC‐FID Chromarod system.

Towards a cyberspatial pedagogy : exploring synchronous online learning potentials

It has been a quarter of a century since William Gibson (1984) coined the term cyberspace in his seminal science fiction novel Neuromancer. Subsequently, a proliferation of online teaching technologies have emerged supporting Virilio’s (1991) contention that, “time and space have ceased to function as meaningful dimensions to human thought and action.” The aim of this presentation is to discuss and demonstrate the innovative modification of an online, synchronous learning environment, Elluminate Live! (eLive), which allows participants to transcend the spatial dimension. Specifically, we present an example of good practice which aimed to enhance student engagement by implementing a structured online tutorial series which replicated the entire first year psychology on-campus tutorial series in the eLive environment. We discuss Student Evaluation of Teaching and Units (SETU) results which support the utility of this pedagogic strategy. Finally, we outline various challenges for the virtual teacher who wishes to implement a structured learning program in the eLive environment.
Gibson, W 1984, Neuromancer, Ace Books, New York, USA.
Virilio, P 1991, The aesthetics of disappearance, Semiotext(e), New York, USA.

Relationship between verbal working memory and the SCAN-C in children with specific language impairment

Purpose: An ongoing concern with the evaluation of auditory processing disorders is the extent that assessment instruments are influenced by higher order cognitive functions. This study examined the relationship between verbal working memory and performance on the Test for Auditory Processing Disorders in Children--Revised (SCAN-C; Keith, 2000b) in children with specific language impairment (SLI) and typically developing (TD) children.

Method: Sixteen children with SLI and 16 TD children ages 8/4 to 11 years participated in the study. The children were presented with the SCAN-C and tests measuring verbal working memory.

Results: Initial comparisons revealed that the SLI group obtained significantly lower scores than the TD group on the SCAN-C. However, after controlling for verbal working memory, significant differences between the 2 groups were no longer observed. Correlational analyses revealed that the composite score from the SCAN-C was related to all tests assessing verbal working memory.

Conclusions: Performance on the SCAN-C may be related to working memory functioning. As a consequence, it is unclear whether difficulty on this task should be viewed as a problem with auditory processing or a problem with verbal working memory.

Voltage stability analysis with optimum size and location based synchronous machine DG

Power loss of a distribution system can be reduced significantly by using optimum size and location of distributed generation (DG). Proper allocation of DG with appropriate size maximizes overall system efficiency. Moreover it improves the reliability and voltage profile of the distribution system. In this paper, IEEE 123 node test feeder has been considered to determine the optimum size and location of a synchronous machine based DG for loss reduction of the system. This paper also investigates the steady-state and dynamic voltage profile of that three phase unbalance distribution network in presence of DG with optimum size. This analysis shows that optimum size of DG at proper location minimizes the power loss as well as improves the dynamic voltage profile of the distribution system.

A high performance position sensorless surface permanent magnet synchronous motor drive based on flux angle

A position sensorless Surface Permanent Magnet Synchronous Motor (SPMSM) drive based on flux angle is presented in this paper. The motor equations are written in rotor fixed d-q reference frame. A PID controller is used to process the speed error to generate the reference torque current keeping the magnetizing current fixed. The estimated stator flux using Recurrent Neural Network (RNN) is used to find out the rotor position. The flux angle and the reference current phasor angle are used in vector rotator to generate the reference phase currents. Hysteresis current controller block controls the switching of the 3-phase inverter to apply voltage to the motor stator. Simulation studies on different operating conditions indicate the acceptability of the drive system. The drive system only requires a speed transducer and is free from position sensor requirement. The proposed control scheme is robust under load torque disturbances and motor parameter variations. It is also simple and low cost to implement in a practical environment.