This paper proposes an energy consumption estimation in the trajectory planning task of an industrial robot (IR) arm manipulator. Human-robot collaborative scheduling has become integral to modern manufacturing. Effective scheduling of human-robot cooperation is crucial for enhancing production efficiency. However, energy-efficient trajectory planning in human-robot interaction remains an unexplored area. To address this, a 6-DoF (Degree of Freedom) robot arm, available in the laboratory, was utilized to assess the energy consumption of this specific robot type. However, his approach can be applied to any robot, whether it’s a human-robot collaboration, a mobile robot, or any other articulated robot arm manipulator.For this goal the electrical and mechanical losses of a 6-DoF robot arm manipulator from the company Universal Robots is modeled and its power losses cost function (PLCF) is derived correspondingly to calculate the electromechanical energy losses. The objective of this paper is to estimate the energy losses in a trajectory planning task in cartesian space for a tool center point (TCP) of the robot, starting from an initial point and resting at a final point. This goal is achieved by examining and analyzing the kinematics and dynamics followed by measuring the velocity and acceleration related terms of each motor at each joint of the UR3e robot arm in a laboratory setup. The results estimate the changes of energy losses in the overall trajectory following of the robot manipulator and presents the results of the estimated and measured reduction terms.

Replacing the conventional silicon-based transistors with the Gallium Nitride High Electron Mobility Transistors (GaN HEMTs) promises higher power densities, switching frequencies and system-level efficiencies due to their significantly superior material properties. Despite the very low static on-state resistance due to the high-density two-Dimensional Electron Gas (2DEG) with high electron mobility, GaN HEMTs suffer from the increased on-state resistance right after switching from the off-state high-voltage to the low on-state voltage, due to charge trapping effects. This phenomenon, also known as current collapse, causes increased power losses in the GaN FET and may lead to reliability issues. In this paper, the dynamic on-state resistance characterization of a 100 V commercially available enhancement mode GaN FET is investigated experimentally for various operating points. The results are compared to those of a Si-based MOSFET.

This paper offers a Topology Optimization (TO) method to replace conventional parameter optimization, which is a common method for electrical machine’s or electromagnetic device’s design optimization. In most of the final designs gained with TO, there are challenges in the manufacturing process using the nowadays available manufacturing technologies. Therefore, this work investigated the approach on two tasks, in the first level a global optimization method, called Enhanced Binary Genetic Algorithm is applied to the design domain. After optimization with this meta-heuristic method, some holes inside the structure or some spread iron cells appear. This drawback will be improved in the second level by one of the image processing methods, called Morphological Reconstruction, to gain a smoother shape to reduce the manufacturing complexities while reaching reasonable technical characteristics. The goal is to find a lighter weight of the structure while preserving the force in a suited amount. The proposed method is applied to an E-core actuator as a case study. After using the proposed hybrid optimization method, air cells appear around some parts of the actuator’s coil, which are used to extend the copper areas, so that the magnetic force considerably increases. In general, it is possible to extend the method to different active parts of the electrical machines.

This paper deals with a deterministic and analytic winding function model for the calculation of the magnetic field inside the air gap of a squirrel cage induction machine (SCIM). Therefore, a voltage equation system is built up, containing fundamental and harmonic voltage and current waves. After solving the system for the current values with a given voltage excitation, a conclusion on the magnetic field is possible. Furthermore, an approach to consider slotting is used. As validation, measurements are taken within the machine air gap, using a flexible printed circuit containing search coils.

The sum of forces acting on the contact layer between a graphite brush and a copper bar has a major influence on its conductivity. Therefore, the current ripple gives a hint to what happens to the commutator during one rotation. In this paper, a conductivity model and a mechanical model are proposed to simulate and evaluate the influence of various forces on the commutation process.

An optimization study to reduce the harmonic components of the magnetic flux density due to the modulation effect in a coaxial Magnetic Gear Transmission system (MaGT) is presented in this paper. The results of the harmonic content analysis of a MaGT are used to optimize the design of a double-stage MaGT configuration for automotive applications presented in previous works. In particular, pole arc to pole pitch ratios of the two rotors and of the modulation ring have been tuned in order to reduce the harmonic content of the magnetic flux density. The comparison between two different case studies is presented in regard to core losses, maximum temperatures and overall MaGT efficiency. These analyses have been carried out by means of analytical formulations and finite element simulations using the FEMM software.

The mechanical encoder increases the cost, the volume and the risk of failure of electrical machines. Therefore, the research on self-sensing control has been enforced within the last years. The concept of short-circuited windings, applied on the rotor of electrical machines, has been modeled by analytic equations and finite element analysis in previous investigations. The goal is to increase the electromagnetic saliency of the machine that is required for the suitability of self-sensing control at standstill and low speed. There, the performance of the concept will be evaluated. First, the measurement results on a test bench without and including SC-windings will be evaluated. Second, the performance of resistance- and inductance-based self-sensing control will be compared. Reasons for the different quality of position estimation of the two concepts will be discussed.

This paper introduces a novel three-phase flux reversal machine. Unlike conventional machines, the proposed machine is based on a multi-layered design with three magnetically independent rotors and stators on the same shaft. Each layer represents a single-phase flux reversal machine (FRM), which is mechanically shifted against each other. Each layer consists of a stator with two teeth, where two magnets of opposite polarity are radially attached to each tooth. The salient rotor consists of three poles, which are located 120° apart. This multilayered structure compensates for shortcomings of the single-phase FRM like high torque pulsations and vanishing starting torque at specific rotor positions. These advantages of the three-phase machine will be supported through various analyses, comparisons and simulations presented in this paper.

The work discusses and finally verifies the working principle of a passive stator cooling concept employing conventional heat pipes. For this purpose a test-setup based on a small power medium speed 6/8-flux-switching permanent magnet machine with an extraordinarily large air-gap of δ=4 mm is manufactured, commissioned and measurements are recorded proving the concept of both: the electromagnetic machine design and particularly the passive stator cooling concept. The elegance of the presented passive cooling principle especially lies in easy adaptability on an existing electrical machine which is already in service, its simple structure, minor requirements of additional cooling equipment and its cooling capabilities. However, some limitation in the maximum dissipatable power and manufacturing are experienced as well.

A resistance- or inductance-based saliency is needed as a prerequisite for signal-injection based encoderless position estimation methods. The differential quantities can be influenced by applying a short-circuited electrical winding on the rotor of an electrical machine. For a configuration that has been optimized in former research, 2D finite element method simulations are carried out. To be able to simulate the machine's behavior via stationary AC simulations, the frozen permeability method is used hereinafter. The advantages for the given application and the method itself will be presented. The results at no-load conditions will be compared to those gained by measurements. In summary, the simulation results at load conditions will be discussed.

In contrast to conventional permanent magnet machines, integrated magnetic gears exhibit different pole pairs in the stator and the rotor. Consequently, a flux modulation of the air gap magnetic field is necessary for torque transmission, wherefore additional flux modulation poles (FMPs) are used. As the number of FMPs adopts to the pole configuration of the stator and the rotor, arbitrary combinations of both are possible. This results in new degrees of freedom in the machine design process, wherefore this paper studies the advantages and disadvantages of a wide range of different stator and rotor pole configurations.

The work presents two alternative ways of cooling a flux-switching permanent magnet machine with a large air-gap length of 3 mm. The investigations are based on a small power machine (DSa= 100 mm, l = 80 mm) which is designed for the needs of a special application where a defined clearance between the stator and rotor is required to ensure the working principle. The increased air-gap volume promotes the machine cooling from the stator inner surface by means of applying ordinary rotor (step) skewing technique for the salient pole reluctance rotor. In order to proof this cooling concept a test-setup is build up for thermal evaluation purposes. A more widely applicable approach for the thermal heat dissipation within the machine stator is also presented. In this case, the heat is directly extracted from the coil sides of the stator phase winding employing heat pipes. This totally passive cooling technique can improve the efficiency of all kinds of machines by keeping the phase resistance at lower levels or alternatively allowing an increase of current density in the slot without the need of additional cooling equipment like a fan, a radiator or a liquid cooling circuit.

At standstill and low-speed, signal-injection methods are required to estimate the rotor position of a permanent magnet synchronous machine (PMSM). Therefore, usually either the resistance- or inductance-based saliency is examined. Although the latter case can be found most in literature, it is possible that the sensorless performance can be improved by exploiting the position information of both saliencies at the same time instead of evaluating only one of both. Therefore, this paper proposes a modified position estimation method which combines both the resistance- and inductance-based saliency. Based on measurement results of a PMSM, the new method is compared to the sole resistance- and inductance-based saliency tracking.

This paper introduces an integrated magnetic gear intended as direct-drive. Next, a magnetic equivalent circuit for the presented gear topology is proposed. This approach uses the principle of virtual work for torque calculation and takes magnetic leakage and saturation into account. Thereby, the approach focuses on a reduction of the computation time compared to finite element simulation. Finally, the suggested approach is verified by the results of a finite element simulation.

This paper deals with the measurement of the magnetic properties of steel and other soft magnetic, electrical conductive, materials at high temperatures up to the Curie temperature and slightly above. At first the theory of measuring the magnetic properties at room temperature is described on the basis of the ring core method and the Epstein method, since aspects of both are used in the developed measurement setup for high temperatures. The heating of the ring-shaped steel sample is achieved by using it as the secondary, short-circuited winding of a transformer. The ring itself is thermally insulated and wound with two coils, which allow the determination of the magnetic properties. The measurements show that the saturation polarization is decreased a little bit up to 500 °C and then drops to zero at slightly above 700 °C. However the initial permeability is increased with temperature and the iron losses for low polarizations are decreased.

Sensorless position estimation based on signal-injection methods always requires a resistance- or inductance-based anisotropy. One way to influence the differential inductances of an electrical machine is the use of a short-circuited electrical winding on the rotor surface. This method is applied to an interior permanent magnet (TPM) machine in this paper. In order to investigate the suitability of a short-circuited rotor winding to improve the sensorless capability of an IPM machine, an optimized rotor concept is derived and investigated by a nonlinear machine model. To verify these findings, the presented machine was built and measured. The measurement results are in good agreement with the simulations and show clearly how a short-circuited rotor winding increases the magnetic saliency for the test signal and in consequence, leads to a significant reduction of the estimation error.

A small size flux-switching permanent magnet machine is designed by means of finite element analysis having a concentrated toroidal winding in the stator and a large air-gap. The design concept is compared to a C-core flux-switching machine having the same magnet volume. Simulation shows that the electromagnetic performance of the toroidal wound FSPM is lower in the first place because of the different winding configuration. However a better cooling of the stator winding is possible so that at full load operation the temperature rise of the winding can be better limited.

In this paper classical electrical machine design schemes are outlined and evaluated in terms of designing eddy current brakes. Next, a generic approach to model single and double stator axial eddy current brakes is proposed. This approach uses coupled electric and magnetic equivalent circuits and takes current displacement, magnetic leakage, fringing and saturation into account. Finally, the suggested generic approach is verified experimentally by actual measurements of a single stator axial eddy current brake.

This manuscript describes the identification process of the parameters of the Jiles-Atherton-model (JAM) which can be used to characterize the magnetic behavior of electrical steel sheets. A simple semi-analytic parameter identification process using only a small set of symmetrical hysteresis loops is proposed, which requires low computational effort in contrast to the intensive numerical optimization algorithms which are normally used to gain the JAM parameters. Finally some aspects concerning the representation of minor loops will be discussed.