Abstract: A magnetic flux pad for receiving or generating magnetic flux. The pad includes two pole areas (11, 12) associated with a magnetically permeable core 14. Coils 17 define the pole areas. The pad allows useable flux to be generated at a significant height above a surface of the pad.

Abstract: An inductive power transfer apparatus may be used for producing or receiving a magnetic field for inductive power transfer. The apparatus has a central coil and two end coils, one of the end coils being provided at each end of the central coil. Some turns of each of the end coils are on one side of the central coil and the remaining turns are on the other side. The end coils act to weaken or cancel flux on one side of the central coil and guide magnetic flux through the central coil to provide an arch shaped flux pattern beyond the apparatus on the other side of the central coil.

Abstract: An inductive power transfer pickup circuit has a pickup coil (L2) and tuning capacitor (C2) connected in series to provide a series resonant circuit. A bi-directional switch (S1) is used to vary the phase angle between the open circuit pickup coil voltage (VOC) and the pickup coil inductor current (iL) to provide a controlled AC supply to an output of the pickup.

Abstract: A multiphase IPT primary track conductor arrangement comprising a first phase conductor and a second phase conductor, the conductors being arranged substantially in a plane and so as to overlap each other and being arranged such that there is substantially balanced mutual coupling between the phase conductors.

Abstract: The present subject matter relates to the control of electromagnetic fields and has particular relevance to wireless power transfer system devices and systems. In particular there is provided a magnetic flux coupling apparatus comprising a coil for generating or receiving magnetic coupling flux; and a leakage flux element separated from the coil by a region of relatively low magnetic permeability and positioned to provide a controlled path for leakage flux independent of coupling flux; wherein the leakage flux element comprises a lossy magnetic material of relatively high magnetic permeability which absorbs energy from a time varying magnetic field to thereby alternate attenuate leakage flux. The apparatus as disclosed herein aids in the suppression of the magnetic flux that leaks out of the air gap in such systems, or which leaks out of a region where magnetic flux is required for inductive power transfer.

Abstract: A magnetic structure for wireless power transfer has a plurality of pieces of magnetically permeable material arranged along a first dimension. Each piece is separated from a neighbouring piece by a gap defining a separation distance which is selected to prevent partial saturation of a region of the structure.

Abstract: A power supply system including a distribution transformer connected to a supply grid and supplying a plurality of remote electric loads over a supply network, measuring means for measuring total power transferred between the grid and loads through the transformer, and control signal generation means to signal some of the loads to switch off in response to determining that the measured power transfer exceeds a maximum set point in order to limit the peak power transferred through the transformer.

Abstract: An inductive charging apparatus includes a primary conductor with at least one node for creating a magnetic field and at least one intermediate resonant circuit including a first coil for receiving inductive power from the node, a second coil operable in use to be driven by current from the first coil to generate a magnetic field for power transfer, and a tuning capacitor coupled to the first and second coils for resonance therewith.

Abstract: An inductive power transfer (IPT) control method is disclosed for controlling the output of an IPT pick-up. The invention involves selectively shunting first and second diodes of a diode bridge to selectively rectify an AC current input for supply to a load, or recirculate the AC current to a resonant circuit coupled to the input of the controller. By controlling the proportion of each positive-negative cycle of the AC input which is rectified/recirculated, the output is regulated. Also disclosed is an IPT controller adapted to perform the method, an IPT pick-up incorporating the IPT controller, and an IPT system incorporating at least one such IPT pick-up.

Abstract: A roadway powered electric vehicle system includes a power supply (101) which makes power available inductively to one or more modules (111) provided in or under a roadway. Modules (111) make a magnetic field selectively available to one or more vehicles travelling over the roadway corresponding to the location of the vehicle. The presence or strength of the magnetic field provided on the roadway may be dependent upon the vehicle type or category.

Abstract: This invention relates to current-fed resonant inverters for electrical power applications to change direct current (DC) into alternating current (AC). One application of the invention is to power supplies for inductive power transfer (IPT) systems. There is provided a resonant inverter including an input for supply of current from a DC power source, a resonant circuit including two coupled inductive elements and a tuning capacitance, the inductive elements being arranged to split current from the power source; a first switching means comprising two switching devices operable in substantially opposite phase to alternately switch current from the power source into the inductive elements; and a second switching means to selectively switch one or more control capacitances into or out of the resonant circuit dependent on a power factor of the resonant circuit.

Abstract: The invention provides an electric autocycle support apparatus comprising an autocycle engagement device adapted to support an autocycle, the engagement device having a coil adapted to provide a magnetic field for inductively charging an autocycle supported by the apparatus. The invention also provides an electric autocycle stand and a charging system.

Abstract: A demand side electric power supply management system is disclosed. The system comprises an islanded power system having a point of coupling to a supply grid. The islanded power system supplies a plurality of electric loads, each of which is associated with a load controller to control the maximum power demanded by that load. A measuring means associated with the point of coupling measures the total power transfer between the grid and the islanded system, and a system controller monitors the measured power transfer relative to a set point and provides a control signal to a plurality of load controllers. Each load controller receives substantially the same control signal and determines the maximum power which the or each load associated with the load controller is allowed to draw from the islanded power system based on information contained in the control signal.

Abstract: An IPT system magnetic flux device for generating or receiving a magnetic flux, has a magnetically permeable core and at least one coil magnetically associated with the core. A shield repels magnetic flux and is located on the opposite side of the core such that the shield includes an outer portion that extends beyond at least part of the perimeter of the core.

Abstract: The present invention relates to a current multiplier primarily in the field of power conversion. The invention relates to a controlled current multiplier with a resonant winding to assist with, for example, power conversion. In particular, but not solely, the invention may broadly consist in a current multiplier comprising: a primary winding associated with a power source; a secondary winding associated with a load; a resonant winding associated with a capacitance; and a control means for controlling an output of the secondary winding to the load, the control means associated with the primary or resonant winding. This allows, for instance, control of the high current output to be placed on a low current winding.

Abstract: A method of charging a battery includes coupling an electricity network or subnetwork to the battery using inductive power transfer, transferring electrical energy to the battery from the electricity network or subnetwork and varying the inductive power transfer using a controller of the electricity network or subnetwork according to at least one predetermined criteria of the electricity network or subnetwork.

Abstract: An inductive power transfer pickup circuit has a pickup coil (L2) and tuning capacitor (C2) connected in series to provide a series resonant circuit. A bi-directional switch (S1) is used to vary the phase angle between the open circuit pickup coil voltage (VOC) and the pickup coil inductor current (iL) to provide a controlled AC supply to an output of the pickup.

Abstract: An inductive power transfer (IPT) pick-up circuit has a full-wave rectifier (D1-D4) coupled to a resonant circuit (L1-C1) and adapted to rectify an AC current received from the resonant circuit. A pair of inductors (L2 L3) are provided, being arranged to couple the rectifier to an output (VLoad) of the pick-up circuit and alternately store and release energy to the output.

Abstract: An inductive power transfer (IPT) control method is disclosed for controlling the output of an IPT pick-up. The invention involves selectively shunting first and second diodes of a diode bridge to selectively rectify an AC current input for supply to a load, or recirculate the AC current to a resonant circuit coupled to the input of the controller. By controlling the proportion of each positive-negative cycle of the AC input which is rectified/recirculated, the output is regulated. Also disclosed is an IPT controller adapted to perform the method, an IPT pick-up incorporating the IPT controller, and an IPT system incorporating at least one such IPT pick-up.

Abstract: An Inductive Power Transfer (IPT) pick-up apparatus includes a magnetically permeable core, a first coil, being wound about the core so as to be inductive coupled therewith such that a current induced in the first coil is most sensitive to a first directional component of magnetic flux and a second coil, being wound about the core so as to be inductively coupled therewith such that a current induced in the second coil is most sensitive to a second directional component of magnetic flux. The first directional component is substantially orthogonal to the second directional component.