An electronic device in a wireless power system may be operable with a removable accessory such as a case. The device may convey wireless power to, from, or through the case while the device is coupled to the case. The device may have coplanar power transmitting and power receiving coils. The removable accessory may have an embedded switchable ferrimagnetic core and a coil that overlaps the switchable ferrimagnetic core. The switchable ferrimagnetic core may be operable in a first state where the switchable ferrimagnetic core is unsaturated. The switchable ferrimagnetic core may be operable in a second state where the switchable ferrimagnetic core is saturated by a magnetic field from a permanent magnet in a wireless power transmitting device. In the second state, the switchable ferrimagnetic core may have a lower magnetic permeability and higher magnetic reluctance than in the first state.

In an electromagnetically moving device 100, a magnetic-flux variation measuring unit 3 is placed at a position which is outside a closed magnetic path established when a movable core 6 and a stationary core 5 are being attached to each other due to permanent magnets 7, and at which a leakage magnetic-flux variation due to movement of the movable core 6 can be measured, so that a behavior of a movable part in a switch, etc. is estimated such that an inflection point time is calculated from the measurement of time-series data of the magnetic-flux variation.

An electromagnetic induction device including a magnetic core having a limb which has a first end and a second end, windings arranged around the limb, and a housing including magnetic material, which housing defines a space in which the magnetic core and the windings are arranged, wherein the housing defines a return path for the primary magnetic flux, enabling primary magnetic flux from the first end of the limb to flow via the housing to the second end of the limb.

An inductive core including a body including a ferromagnetic material and a magnet, the magnet forming a first path for circulating of magnetic flux lines produced by the magnet, and the ferromagnetic material at least partially forming a second path for circulating the magnetic flux lines, wherein the ferromagnetic material extends continuously between the poles of the magnet along the poles of the magnet and makes contact with at least a part of an exterior lateral wall of the magnet extending between its poles.

An AC permanent magnet gain transformer device and its voltage regulation and control method. This device adds permanent magnet or permanent magnet assembly to the structure of traditional transformer, the magnetic pole surface of permanent magnet closely clings to laminated iron core, so that the intrinsic permanent magnetic potential of permanent magnet could be elicited under the excitation of the excitation current of primary winding, overlapped and compounded with excitation magnetic potential in the general magnetic loop of closed-loop laminated iron core, and so, it's able to induce the induction electromotive force formed after the superposition of excitation flux and permanent magnet flux at the output end of secondary winding. The method for voltage regulation and control of this invention is to: input a certain amplitude of pulse current to the primary winding in order to guarantee the generation of compound excitation effect, and change the pulse count of pulse current per unit time in order to change and adjust the input and output power of this AC permanent magnet gain transformer device. This AC permanent magnet gain transformer device and its voltage regulation and control method further enhance the power transfer efficiency of transformer device, thus make up the intrinsic spoilage of traditional winding coil and laminated iron core, and save energy.

An electronic device in a wireless power system may be operable with a removable accessory such as a case. The device may convey wireless power to, from, or through the case while the device is coupled to the case. The device may have coplanar power transmitting and power receiving coils. The removable accessory may have an embedded switchable ferrimagnetic core and a coil that overlaps the switchable ferrimagnetic core. The switchable ferrimagnetic core may be operable in a first state where the switchable ferrimagnetic core is unsaturated. The switchable ferrimagnetic core may be operable in a second state where the switchable ferrimagnetic core is saturated by a magnetic field from a permanent magnet in a wireless power transmitting device. In the second state, the switchable ferrimagnetic core may have a lower magnetic permeability and higher magnetic reluctance than in the first state.

An energy transfer element comprises a magnetic core having a gap in a magnetic path. Magnetizable material producing an initial flux density is positioned in the gap. One or more power windings is wrapped around the magnetic path. When the magnetizable material is magnetized the flux density produced by the magnetized material is offset from the initial flux density. The core is a toroid magnetic core or is comprised of two core pieces. The magnetizable material is an unmagnetized magnet or a mixture of a suspension medium comprising uncured epoxy and magnetizable particles. The magnetizable particles are selected from a group comprising Neodymium Iron Boron (NdFeB) based materials or Samarium Cobalt (SmCo) based material.

An AC permanent magnet gain transformer device and its voltage regulation and control method. This device adds permanent magnet or permanent magnet assembly to the structure of traditional transformer, the magnetic pole surface of permanent magnet closely clings to laminated iron core, so that the intrinsic permanent magnetic potential of permanent magnet could be elicited under the excitation of the excitation current of primary winding, overlapped and compounded with excitation magnetic potential in the general magnetic loop of closed-loop laminated iron core, and so, it's able to induce the induction electromotive force formed after the superposition of excitation flux and permanent magnet flux at the output end of secondary winding. The method for voltage regulation and control of this invention is to: input a certain amplitude of pulse current to the primary winding in order to guarantee the generation of compound excitation effect, and change the pulse count of pulse current per unit time in order to change and adjust the input and output power of this AC permanent magnet gain transformer device. This AC permanent magnet gain transformer device and its voltage regulation and control method further enhance the power transfer efficiency of transformer device, thus make up the intrinsic spoilage of traditional winding coil and laminated iron core, and save energy.

An energy transfer element comprises a magnetic core having a gap in a magnetic path. Magnetizable material producing an initial flux density is positioned in the gap. One or more power windings is wrapped around the magnetic path. When the magnetizable material is magnetized the flux density produced by the magnetized material is offset from the initial flux density. The core is a toroid magnetic core or is comprised of two core pieces. The magnetizable material is an unmagnetized magnet or a mixture of a suspension medium comprising uncured epoxy and magnetizable particles. The magnetizable particles are selected from a group comprising Neodymium Iron Boron (NdFeB) based materials or Samarium Cobalt (SmCo) based material.

A fault current limiter (FCL) has a core structure with a first and second magnetisable core members and an AC magnetomotive force source configured to generate a varying magnetic flux in at least a portion of the first and second magnetisable core members. Static magnetomotive force sources being positioned to provide a magnetic circuit within at least part of the magnetisable core members. The FCL may have a ring core structure and the static magnetomotive force sources may include a mitred or tapered joint interface with the core member.