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The construction of new electronic unit has been caused by the development of new transient techniques based on single-probe sensors. Such a sensor is the Planar Hot Disc sensor (PHD). This sensor generates the heat pulse and sense the temperature response in the same time, so the heater and thermometer are unified. The heater is made of nickel foil with a reasonable high value of the temperature...
The role of intraluminal thrombus (ILT) has special attention in these studies. One of the papers showed that asymmetrical intraluminal thrombus deposition (ATDI) has an important role in growth of the AAA. The aim of our study was to assess the asymmetrical thrombus deposition index in ruptured and symptomatic aneurysms. We collected data for 33 aneurysms, 21 (63.63%) asymptomatic and 12 (33.37%)...
Windings printed on flexible circuit board (Flex-PCB) offers the opportunity to improve significantly the performance of slotless BLDC motors since, compared with windings made from copper wire, they may have more complex shapes in addition to a variable conductor cross-section along the winding loops. This paper focuses on the shape optimization of windings printed on FlexPCB using a genetic algorithm...
A large number of analyses performed in a biochemical laboratory requires that results of these analyses are automatically acquired from analyzers which can be of different types and produced by various producers. Automatic data acquisition prevents errors which are possible if results are manually transcribed into reports for patients. Beside this, acquired results are saved in database from where...
An on-line synchronous motor parameter estimation technique is introduced. The motor is driven sensor-lessly with a Kalman filter. A second Kalman filter, that works in parallel with the main one, estimates the motor model parameters. Thanks to the parameter estimation, the accuracy of the Kalman filter estimations of position and speed increase and thus the global performance of the drive. Theoretical...
An electromechanical clamping system for the transmission of the force produced by a piezoelectric stack to an axis is presented. The axial force which the axis can withstand before slipping is evaluated with a compression machine and easily reaches 2000 N. Further developments are the driving and supply electronic realization and the whole actuator prototyping.
In the abdominal segment of the human aorta under a patient's average resting conditions, pulsatile blood flow exhibits complex laminar patterns with secondary flows induced by adjacent branches and irregular vessel geometries. The hyperelastic material model of aorta wall should be taken into account. Prediction of influence of dynamic blood flow on natural history of aneurysmatic disease and outcome...
The paper presents an optimization design of an in-wheel BLDC motor for a kick scooter. The optimization is performed using a genetic optimization tool combined with a FEM commercial software. The new contributions of the paper are: (i) introduction of three operating modes for which the motor is optimized with a reduced number of FEM simulations and (ii) new approach to simultaneously maximize the...
This paper focuses on the maximization of the torque-to-weight ratio of permanent magnet synchronous motors (PMSM) using a topology optimization method. It aims at finding the optimal design that either maximizes the torque for a given weight or minimizes the weight for a required torque. The analysis presented in this paper besides considers radial and tangential permanent magnets. The paper shows...
This paper introduces a promising technique for detecting the rotor position of a PM motor at standstill. The technique is based on the B-H hysteresis characteristics of the stator iron. Depending on the rotor position, a very particular phenomenon related to B-H hysteresis appears. This phenomenon permits to detect the electrical position of a non-salient rotor.
In order to control the speed and/or position of permanent magnet (PM) motors, they require position sensors. Basically, the auto-commutation needs 3 sensors for a 3-phase motor. In micro-motors, as there is no space for the sensors, self-sensing must be used. In any case, suppression of the sensors enhances the overall reliability. The motor becomes a sensor itself and electromagnetic phenomena are...
A sensorless position detection technique for a permanent magnet (PM) motor with non-salient rotor is presented. It is shown that the phase self inductances and resistances measured at higher frequencies vary slightly with the rotor position. The origin of the variations is found in the iron B-H hysteresis characteristics. In order to exploit these small variations for the rotor position detection,...
We present an analytical solution for the induced eddy currents and the corresponding losses generated in the rotor of a slotless permanent magnet (PM) motor. The field excitation is a current layer placed at the stator interior surface. The solution is based on an analytical solution of the diffusion equation using double Fourier series in complex domain. The results are verified using an FEM software.
The paper presents a completely analytical solution for the magnetic field, the induced eddy currents and corresponding losses in a toroidal laminated core with a rectangular cross section. The diffusion equation is analytically solved using a separation of variables in a cylindrical coordinate system, and accurate conditions for the weak and strong diffusion effect are determined. An equivalent resistance...
Web mashups are applications that combine data from various sources and present it to users in an integrated way. This paper investigates potential sources of time- and location-related data, the procedures used for obtaining this data and how this data can be represented on a map and a timeline so that these representations are linked. The outcome is full integration of all these components into...
The paper presents a complete mathematical analysis of a BLDC motor commutation which results in the motor static characteristics torque-speed and efficiency-speed. The motor, having a sinusoidal back emf, is supplied from a DC source via a 6-leg inverter using the 120degON operation. The formulas for the phase currents and voltages are derived. The first harmonic of the phase voltage is determined,...
This paper presents a method to optimize two linear actuator configurations. The method is stochastic and combines a genetic algorithm (GA) and FEM (finite element method) model generated with the commercial software FEMM. The optimization is performed in order to respect the load curve and speed references during opening and closing of the actuator.
In this paper it is shown that the phase self inductance and resistance, both measured at a high frequency, of a permanent magnet (PM) motor with non-salient rotor vary slightly with the rotor position. The origin of these variations is deeply investigated, taking into account typical physical phenomena present in PM motor. Surprisingly, no classical approach can explain these variations. The physical...
We present an optimization design of a slotless permanent-magnet brushless dc motor (400 W, 6000 rpm), with two-segment Halbach arrays. The optimization is based on a motor analytical model which is obtained by solving the magnetic scalar potential using the Fourier series. We show that the iron-cored Halbach configuration is better than the classical one and that the air-cored Halbach configuration...
The paper presents a comparison between analytical model, the finite elements method (FEM) simulations and measurements for a brushless DC motor used in a solar airplane project. In the preliminary conception phase, an optimization using an analytical model is performed. The motor efficiency and its weight are the key parameters. According to the obtained theoretical optimal configuration, a prototype...
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