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Magnetic circuit

About: Magnetic circuit is a research topic. Over the lifetime, 15707 publications have been published within this topic receiving 118099 citations.


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Journal ArticleDOI
TL;DR: In this paper, a 2D finite element simulation of moving structure including the nonlinear magnetic behavior and a dynamical hysteresis model of the magnetic circuit is used to evaluate the induction evolution with time in any point of the motor.
Abstract: A method to estimate precise iron loss in an electrical machine is presented. This method implements a 2D finite element simulation of moving structure including the non-linear magnetic behaviour and a new dynamical hysteresis model of the magnetic circuit. The 2D finite element simulation is used to evaluate the induction evolution with time in any point of the motor structure. The time evolution induction signal is then used as the input of the dynamical hysteresis model to estimate the hysteresis cycle and therefore local iron loss. Results on a 4 kW, 4-pole, 3-phase sine fed induction motor show a good agreement between theoretical estimation and measurement. For the first time, it is shown that rotor loss represents 30% of the motor iron loss.

36 citations

Patent
17 Sep 1997
TL;DR: In this article, the authors proposed a low-noise toroidal TFH device including a solenoidal or helical coil with low coil resistance and inductance, especially suitable for very high magnetic recording areal densities and channel frequencies.
Abstract: The invention relates to a low-noise toroidal TFH device including a solenoidal or helical coil with low coil resistance and inductance, especially suitable for very high magnetic recording areal densities and channel frequencies. The length of a solenoidal coil turn is only about 20-30% that of an average turn in the conventional planar spiral coil design. This allows either reduction of the device thermal noise (by about 6 dB) and/or increase of the device operational frequency bandwidth (by a factor of 3-5). Also, the solenoidal coil coupling efficiency between each turn and the magnetic core is practically 100%, thereby improving the write and read-back efficiencies. Other features of the invention include a non-via large back-closure contact area between the bottom and top magnetic poles along their entire back-side width, and elimination of all other open branches and loose ends in the magnetic circuit. The magnetic core has a gradual, smooth toroidal (or a horse-shoe) shape with no loose ends, nooks, crevices, or sharp corners. The larger back-closure contact area decreases the magnetic core reluctance and improves the device efficiency. Utilization of a soft non-magnetic seed-layer, such as gold, eliminates interference noise due to the conventional magnetic (NiFe) seed-layer. Slight mechanical texturing (scratching) of the seed-layer along the intended easy axis helps to define and induce strong magnetic uniaxial anisotropy in the plated magnetic poles. All these features facilitate significant reduction of Barkhausen and other sources of device noise.

36 citations

Journal ArticleDOI
TL;DR: In this article, an equivalence between the equations of the reluctance network method and the edge element method has been presented, where the edge values of magnetic vector potential represent the loop fluxes in reluctance network and magnetic scalar potential is determined in the centre of gravity of the element.
Abstract: Equivalence between the equations of the reluctance network method and the equations of the edge element method has been presented. The edge values of magnetic vector potential represent the loop fluxes in reluctance network Magnetomotive forces in the branches of the reluctance network are defined by the edge values of current vector potential. The magnetic scalar potential is determined in the centre of gravity of the element. The reluctance network formed by the edge element method contains mutual reluctances.

36 citations

Journal ArticleDOI
TL;DR: The key is to artificially construct reluctance effect in a consequent-pole Vernier permanent magnet machine (CP-VPMM) by introducing extra dc field excitation equipped with the relieving-dc-saturation ability, making it especially suitable for multimode starter generator application.
Abstract: Benefiting from flexible flux control and short-circuit withstand ability, the hybrid excitation machine is an emerging starter generator solution for hybrid electric vehicle propulsion. However, to realize a brushless hybrid design in conventional permanent magnet machines, a three-dimensional magnetic circuit is usually adopted, leading to complicated mechanical structure and torque density sacrifice. To address this issue, a new relieving-dc-saturation hybrid excitation Vernier machine is proposed in this article, which integrates good torque density and bidirectional flux control within a simple and brushless structure. The key is to artificially construct reluctance effect in a consequent-pole Vernier permanent magnet machine (CP-VPMM) by introducing extra dc field excitation equipped with the relieving-dc-saturation ability. In this way, the advantages of bidirectional flux control in stator-dc-excited reluctance machine and good torque density in CP-VPMM are well combined in this topology, making it especially suitable for multimode starter generator application. In this article, the machine structure and its design mechanism are introduced, with its electromagnetic performance evaluated by the finite-element simulation. A prototype is manufactured and tested. Experiment results verify the feasibility of this new topology.

36 citations

Patent
27 Mar 1972
TL;DR: In this article, a position control system using magnetic force is presented, in which at least one pole of an electromagnet is opposed to a magnetic substance of a controlled object through an air gap therebetween so that a magnetic circuit including the magnetic material, the air gap, and the electromagnetic material is provided.
Abstract: The position control system using magnetic force, in which at least one pole of an electromagnet is opposed to a magnetic substance of a controlled object through an air gap therebetween so that a magnetic circuit including the magnetic substance, the air gap and the electromagnet is provided. The width of the air gap is preset to a value more than a predetermined width when the control current is zero. The controlled object is supported by at least one spring so as to be movable along a direction in which the magnetic force functions between the electromagnet and the magnetic substance. The control current of the electromagnet is controlled for adjusting the magnetic force and also a width of the air gap so as to obtain a desired position of the controlled object along the above mentioned direction. The magnetic flux density of the magnetic circuit substantially saturates at a condition where the air gap reaches a predetermined distance, while an elastic force of the spring is balanced with the magnetic force within the elastic region of the spring at the above-mentioned condition to avoid mutual collision between the controlled object and the electromagnet. The above mentioned principle can be modified for performing two or three dimensional control and rotation control for the controlled object.

36 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202359
2022146
2021286
2020462
2019580
2018555