Ernest Mendrela

3-D space modeling of rotary-linear induction motor with twin-armature

The performance of twin-armature rotary-linear induction motor is presented in this paper. The stator consists of a rotary armature and linear armature placed aside one another. Both armatures have a common rotor which consists of solid iron cylinder covered with a thin copper layer. The rotor can move with helical motion. A 3-D space FEM is used to determine the magnetic field, axial force, and torque developed by the motor. The results obtained from modeling are verified by the test carried out on experimental model of the motor.

Modeling of induction motors with one and two degrees of mechanical freedom

Preface. 1: Introduction. 2: Mono-harmonic induction motor with two degrees of mechanical freedom (IM-2DMF). 1. Idea of motor and magnetic field description. 2. Rotor slip. 3. Electromagnetic field in multilayer motor. 4. Motor equivalent circuit. 5. Performance characteristics. 6. Conversion of mathematical model of IM-2DMF into one of IM-1DMF. 3: Computational model of IM-2DMF taking into account finite dimensions of primary and current and winding asymmetries. 1. 3-D field model of IM-2DMF. 2. Multiharmonic equivalent circuit. 4: Simulation of induction motors with two degrees of mechanical freedom. 1. Rotary-linear induction motors. 2. Induction motor with spherical motor. 3. X-Y linear induction motor. 5: Simulation of induction motors with one degree of mechanical freedom. 1. Linear induction motors. 2. Disc-type induction motors. 3. MHD machine-induction pump. Appendix. References. Index.

A Novel Equivalent Circuit Model of Linear Induction Motors Considering Static and Dynamic End Effects

A novel steady-state equivalent circuit model for linear induction motors is presented in this paper. The novelty resides in classification and inclusion of end effects that are considered static and dynamic, namely as speed-independent and speed-dependent end effects. The Duncan model is used to address the dynamic end effect and appropriately modified to account for the saturation of back iron. The static end effect, which manifests itself by the alternating field component, is represented by an additional circuit branch similar to the branches of the motor with an alternating magnetic field. Each type of end effect is modeled and included separately. The results regarding determination of basic performance characteristics are compared with those obtained from finite element (FE) simulation. The procedure to identify the parameters of this circuit using a FE model is also presented.

Modeling dynamic end effects in rotary armature of rotary-linear induction motor

The performance of twin-armature rotary-linear induction motor is presented in this paper. The stator consists of a rotary armature and linear armature placed aside one another. Both armatures have a common rotor which consists of solid iron cylinder covered with a thin copper layer. The rotor can move rotary, linearly or with helical motion. The linear motion generates dynamic end effect on both linear and rotary armature. Modeling such an effect in rotary armature is a significant challenge as it requires a solution considering motion with two degrees of mechanical freedom. The approach used to address linear motion on rotary armature is based on the combination of transient time-domain finite element model and frequency-domain slip frequency technique. The results obtained from finite element modeling are then verified by test carried out on experimental model of the motor what validates the proposed method.

Multilayer-Winding Versus Switched-Flux Permanent-Magnet AC Machines for Gearless Applications in Clean-Energy Systems

A variety of clean-energy systems, such as electric and hybrid vehicles or wind-power sources, can appreciably benefit from motors or generators directly connected to the mechanical part of the system. This paper describes the development and experimental investigation of two radically different low-speed permanent-magnet ac machines: a multilayer-winding synchronous machine and a switched-flux machine. The study allows an in-depth comparison of these divergent concepts from the viewpoint of practical applications in the clean-energy infrastructure.

A method of determination of the distance between fictitious primaries in computational model of linear induction motor used in fourier series technique

ContentsThe Fourier series method used to solve differential field equations in linear induction motors (LIM) is based on a computational model in which the real primary is replaced by a series of fictitious primaries distributed along the direction of motion. The distance between adjacent primaries ought to be big enough to avoid the influence of the preceding primary field on the following one. In the paper, the authors propose a method of determination of this distance but only for the computational LIM model which takes into account the finite length of primary current sheet while the iron core is assumed to be infinitely long. As an example of application of this method calculations have been made for low and high speed LIMs.ÜbersichtDie zur Auflösung von Differentialfeldgleichungen im linearen Induktionsmotor (LIM) angewandte Methode basiert auf einem rechnerischen Modell, in dem der reelle Primäranker durch mehrere in der Bewegungsrichtung angeordnete imaginäre Primäranker ersetzt wird. Der Abstand zwischen aufeinanderfolgenden Primärankern soll genügend groß scin, damit die Einwirkung des vorangehenden Primärankerfeldes auf das folgende vermieden wird. Von den Verfassern wird ein Verfahren zur Bestimmung dieser Abstände vorgeschlagen, und zwar für das rechnerische LIM-Modell, das die endliche Strombelaglänge berücksichtigt, während sich der Eisenkern bis zur Unendlichkeit dehnt. Als Anwendungsbeispiel dieser Methode wurden Berechnungen für LIM bei niedriger und hoher Geschwindigkeit dargestellt.

3D Edge Element Calculations of Electrical Motor with Double Cylindrical Rotor

The brushless permanent magnet motor with cylindrical double rotor is investigated. The calculations have been performed using the 3D edge element method (EEM). The authors developed computer software for 3D electromagnetic field computations. Selected results of electromagnetic torque characteristics, for the different motor dimensions are compared and discussed.

Finite element analysis of saturation effects in a tubular linear permanent magnet machine

Purpose – The aim of the paper is to find the simple and accurate model for the analysis of a drive with a tubular linear permanent magnet machine (TLPMM). Attention is paid to the models that take into account the saturation effects and is useful in the calculations of electromagnetic forces.Design/methodology/approach – A circuit model and a field‐circuit model (FCM) are considered. The FCM includes finite element (FE) formulation for the axisymmetric electromagnetic field, equations which define the connections of windings and converter elements, and expressions that describe the control system. The FE method is used to determine the parameters of the circuit model. In order to simplify the circuit model, saturation effects caused by armature reaction are ignored. The electromagnetic force calculation is based on the virtual work principle and uses an approximate expression for the derivative of system co‐energy. The results obtained for the proposed models have been compared.Findings – The proposed FE...

Induction Motors with Rotor Helical Motion

A demand for sophisticated motion control is steadily increasing in several advanced application fields, such as robotics, tooling machines, pick-and-place systems, etc. These kinds of applications require implementation of at least two or more conventional motors/actuators, often operating with different type of mechanical gear. Electric motors/actuators that are able directly perform complex motion (with multiple degrees of mechanical freedom – multi-DoMF) may provide appreciable benefits in terms of performances, volume, weight and cost.

Comparative method for twin-rotor PM brushless motors applied as in-wheel motors

A quick, simplified method is proposed to compare the axial-flux and radial-flux twin-rotor PM brushless (TRPMBL) motors, with slot-less stators, for the application of in-wheel motor for the gearless drive of an electric vehicle. This method allows answering which of these two motors with the same magnetic and current loading properties and with the same radius and axial length, when built into the wheel gives greater torque. An expression is derived for the ratio of torques of such motors. To check the validity of this method, the axial-flux and radial-flux TRPMBL motors of the same volume are modeled using FEM and their torques are compared.