Design and Analysis of Magnetic Shielding Mechanism for Wireless Power Transfer System Based on Composite Materials

Abstract

In a wireless power transfer (WPT) system, in order to reduce the leakage of the magnetic field in the space and to improve the transmission efficiency of the system, a magnetic shielding mechanism is usually added to the coupling coil. However, the commonly used ferrite material has defects of brittleness, easy cracking, and a low saturation limit. Therefore, a novel magnetic shielding mechanism based on a quartz fiber and nanocrystalline reinforced resin matrix composite material was proposed, and epoxy resin and cross-laminate-splicing processes were used to improve the resistivity of the nanocrystalline material and to improve the eddy current loss. A discretized geometric model was designed for quartz fiber, and the effects of different shielding structures on the space magnetic field and the power loss were simulated and analyzed. In the experiment, a space magnetic field measurement system was built, and the transmission efficiency was analyzed. The results showed that the new magnetic shielding mechanism has a good shielding effect, can effectively suppress leakage of the magnetic field in space, reduce the weight, and improve the mechanical performance while also achieving a high transmission efficiency of 85.6%.

Bayesian neural network based inductance calculations of wireless power transfer systems

“…Furthermore, as N1 and N2 increase, the amount of calculation increases and the processing time becomes enormous. ( 4) does not include the effects of the ferrite shields and M is varied by the effects of the ferrite shields as well as L [33]. Therefore, the conventional inductance approximate equations cannot calculate the self and mutual inductances of WPT systems with coils and ferrite shields, but the proposed method does.…”

Ferrite-Loaded Inverted Microstrip Line-Based Artificial Magnetic Conductor for the Magnetic Shielding Applications of a Wireless Power Transfer System

“…According to the guidelines of the International Commission on Non-Ionizing Radiation Protection (ICNIRP), the magnetic field leakage should be minimized to a safe level of 270 mG for humans [9]. Several studies are underway to minimize magnetic field leakage and improve PTE [10][11][12][13][14][15][16][17][18][19]. For example, the PTE can be improved using coated wires such as litz and magneto-plated wires [10], by adding relay coils [11], or by using metamaterials [17][18][19].…”

“…For example, the PTE can be improved using coated wires such as litz and magneto-plated wires [10], by adding relay coils [11], or by using metamaterials [17][18][19]. For magnetic shielding, placement of ferromagnetic materials or ferrites behind the Tx and Rx coils are widely used in very low frequency (VLF) to low frequency (LF) applications [12], [13]. In previous studies [14][15][16], magnetic shielding has been implemented using additional active or passive cancelation coils placed behind the Tx coils, which can generate the magnetic field in the opposite direction to the backside of the Tx coil.…”

“…The overall profile, weight, and complexity of the IML-based AMC structure were greatly improved compared with those of AMC-based magnetic shielding structures. The possible applications of the proposed AMC in the WPTS may include smart home appliances utilizing wireless charging Several studies are underway to minimize magnetic field leakage and improve PTE [10][11][12][13][14][15][16][17][18][19]. For example, the PTE can be improved using coated wires such as litz and magneto-plated wires [10], by adding relay coils [11], or by using metamaterials [17][18][19].…”

High-Power-Factor LC Series Resonant Converter Operating Off-Resonance with Inductors Elaborated with a Composed Material of Resin/Iron Powder

“…The problem with using ferrite cores is that they have a low saturation flux density, typically between 0.2 and 0.5 T, whereas air-core inductors have drawbacks with unwanted stray inductances, causing electromagnetic interference that can affect nearby devices [14][15][16]. Regarding the nanocrystalline cores, these belong to the category of the so-called "soft magnetic composites", which have presented good magnetic properties such as high saturation flux density, high permeability, and a high Curie temperature, in addition to being more resistant in structure compared to ferrite cores [17,18].…”