Magnetic circuit

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

Low-frequency magnetic fields from electrical appliances and power lines

Abstract: The relationship between magnetic fields and the health of people is increasingly being investigated. International organizations have proposed bylaws that put limits on the value of the generated magnetic field. In this work, we measure the magnetic field created by electrical appliances and high voltage lines and we analyze the degree of compliance with recent applicable European regulation. The simulation of the magnetic field generated by electrical lines through a simple model accurately predicts the measured values. The model is used to simulate the behavior of the lines under given conditions. In both cases, an FFT analysis of the magnetic field waveform was performed to study the frequency and amplitude of the possible induced currents.

Comparison of Tripolar and Circular Pads for IPT Charging Systems

Abstract: Recently, a magnetic pad called the tripolar pad (TPP) has been introduced for inductive power transfer (IPT) systems. This paper evaluates the effective coupling factor and leakage magnetic field of a 20-kW IPT system that uses a combination of TPP and circular pad (CP) topologies over a range of lateral displacements. The results show that the effective coupling factor and the leakage magnetic field of the TPP–TPP system are substantially better when the secondary is displaced away from ideal alignment. Leakage magnetic field is reduced up to 43% compared to the CP–CP system at the worst-case misalignment, which is due to the ability of the TPP–TPP system to generate and capture different types of magnetic field shapes. Simulation methods for both the TPP and CP are validated in the laboratory using a 2-kW system operating at 85 kHz.

Leakage inductance and termination effects in a high-power planar magnetic structure

Abstract: The leakage inductance of planar magnetic structures designed for high-frequency power electronics applications is a critical performance parameter that significantly effects circuit operation. This paper presents numerical models for a particular high power (100-500 W) transformer designed for low-profile applications. The impact that secondary winding terminations have on the leakage characteristics of the device is examined using a set of laboratory measurements. It is shown that the effective inductance the transformer presents to the circuit can be several times the inductance calculated or measured based on an ideal short-circuited winding. These results point toward some general design guidelines that are useful for minimizing leakage inductance for planar structures. >

A large-force, fully-integrated MEMS magnetic actuator

Abstract: A large-force, fully-integrated, electromagnetic actuator for microrelay applications is presented. Designed for high efficiency, the actuator integrates a cantilever beam and planar electromagnetic coil into a low-reluctance magnetic circuit using a combined surface and bulk micromachining process. Experimental testing shows that a coil current of 80 mA generates a 200 /spl mu/N actuation force. Theoretical extrapolation of the data indicates that an actuation force in the millinewton range can be produced by a coil current of 800 mA. The tested actuators have a footprint of less than 8 mm/sup 2/ and their fabrication is potentially compatible with CMOS processing technology.

Demagnetization and Permanent-Magnet Minimization Anal-yses of Less-Rare-Earth Interior Permanent-Magnet Synchronous Machines Used for Electric Vehicles.

Abstract: Rare-earth permanent magnet synchronous machines (RE-PMSMs) are widely used in electric vehicles (EVs) due to their characteristics of high efficiency, high torque density and high power factor. While the dramatic price fluctuations of the rare-earth permanent magnets (PMs) have been restricted the application of RE-PMSMs. Hence, the less-rareearth interior permanent magnet synchronous machines (LRE-IPMSMs), which combine the features of high electromagnetic performance as well as low cost, have attracted increasing attention in recent years [1]. The anti-demagnetization ability of the LRE-IPMSMs is crucial to the machine safety [2]. In [3], the tapered flux barriers are adopted to improve the anti-demagnetization ability of the LRE-IPMSMs. In [4], a practical analytical approach is proposed to express the direct link between the PM thickness and the demagnetization limit. In addition, the PM minimization is also a significant issue for the LRE-IPMSMs as it is crucial to decrease the machine cost. In [5], an analytical procedure is proposed to reduce the PM quantity in the LRE-IPMSMs without affecting the torque versus speed performance. In this paper, the demagnetization equivalent magnetic circuit (EMC) model of the investigated LRE-IPMSM is established and the effects of structure parameters on the PM flux density are investigated. The PM minimization design of the LRE-IPMSMs is obtained on the premise of no side effect on the machine output toque and anti-demagnetization ability.