Abstract: A pick-up circuit for an inductive power transfer (IPT) system includes a series-tuned pick-up coil and a plurality of parallel AC processing circuits provided between the series-tuned pick-up coil and an output, each processing circuit being adapted to produce an output signal based directly or indirectly at least in part on a voltage of the series-tuned pick-up coil and including a switch for selectively coupling the processing circuit to the output so as to selectively provide the respective output signal to the output of the pick-up circuit.

Abstract: An apparatus for generating and/or transmitting communications signals, the apparatus including a system for generating signals at a first frequency, a system for mixing the frequency of the generated signals from the first frequency down to a second frequency and a near field antenna for receiving the signals at the second frequency and being provided sufficiently near to a wire transmission line so as to wirelessly couple thereto.

Abstract: An inductively coupled power transfer system has a power pick-up that uses an asymmetrical magnetically permeable core (103, 105, 106, 107). Such cores have been found to provide a significant increase in the output power for given losses and given core volume when transferring power from a primary conductive path (101) to a secondary coil (104) provided on the core.

Abstract: An inductive power transfer (IPT) pad and system for the charging of electric and hybid electric vehicles. The batter of such a vehicle can be selectively coupled to a high power electrical supply for fast charging or a lower power electrical supply for charging using IPT. The batteries of the vehicles are used in a system to control the load demand in an electricity network through variations of the frequency of power supplied.

Abstract: The present invention provides a system for controlling one or more operating unites in an inductive power transfer (IPT) system. Each operating unit includes a pick-up coil that takes power from a primary conductor or track over an air gap. The operating unit is controlled by frequency modulating the primary conductor power supply to send a control instruction which is decoded by the operating unit. The instruction is decoded by generating a signal using a local oscillator in the operating unit and using the signal to detect changes in the frequency of the current in the primary conductor. Such a system can be used, for example, to control inductively powered road-studs that include a light source for controlling traffic on a roadway. A narrow band modulated data transmission system and method for controlling an operating unit are also provided.

Abstract: An IPT pick-up circuit includes a resonant circuit including a pick-up inductor and a tuning capacitance in parallel with the pick-up inductor, a control system to control power transfer to the pick-up circuit and a power conditioning impedance provided in series between the resonant circuit and the control system, selected to provide a required power factor in the resonant circuit.

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.

Abstract: A method is provided for controlling a resonant circuit (1) of an ICPT system. The resonant circuit has a controlled variable reactance (2), and a predetermined perturbation is introduced in the magnitude of variable reactance. The change in a property of the resonant circuit in response to the perturbation is sensed, and the variable reactance is varied to alter the resonant frequency of the circuit in response to the sensed change.

Abstract: An arrangement for supplying a load with electrical energy from a power source comprises a textile, woven floor covering (101) with longitudinally running warp threads and transversely running weft threads, three or more current conductors (106) that are spaced apart and substantially parallel to one another being woven in either as warp threads or as weft threads, the current conductors replacing part of a filling warp, a binding warp or the weft threads during the weaving operation. The arrangement also comprises a feed for the connection of the current conductors (106) to the power source and a coupling device (130) for picking up electrical energy from the current conductors (106) in the floor covering (101) and transporting it further to the load when the coupling device (130) is brought into a power pick-up area of the floor covering (101).

Abstract: An ICPT system has a single phase power supply which energises a conductive path (13) and has an inverter (5) to provide an alternating current at an operating frequency greater than the single phase utility supply frequency in the conductive path. The inverter modulates the amplitude of the alternating current with respect to the utility supply frequency such that the amplitude of the alternating current varies. The pick-up has an energy storage element (26) to provide a continuous supply of power to a load (27) irrespective of the varying amplitude of the alternating current in the conductive path.

Abstract: Power taken inductively from the alternating current in a track is received by a resonant circuit which is at least partially decoupled by a switching circuit asynchronously with the frequency of the power supply. The switch on and off time is controlled to regulate the output power, either the voltage or the current output being a function of the switch off time divided by the switch on time.

Abstract: The present invention provides a system for controlling one or more operating unites in an inductive power transfer (IPT) system. Each operating unit includes a pick-up coil that takes power from a primary conductor or track over an air gap. The operating unit is controlled by frequency modulating the primary conductor power supply to send a control instruction which is decoded by the operating unit. The instruction is decoded by generating a signal using a local oscillator in the operating unit and using the signal to detect changes in the frequency of the current in the primary conductor. Such a system can be used, for example, to control inductively powered road-studs that include a light source for controlling traffic on a roadway. A narrow band modulated data transmission system and method for controlling an operating unit are also provided.

Abstract: Power taken inductively from the alternating current in a track is received by a resonant circuit which is output controlled by a switching circuit asynchronous with the frequency of the power supply. The switch on and off time is controlled to regulate the output power and the circuit is such that on light loads the resonant circuit decouples from the track.

Abstract: Power taken inductively from the alternating current in a track is received by a resonant circuit which is at least partially decoupled by a switching circuit asynchronously with the frequency of the power supply. The switch on and off time is controlled to regulate the output power, either the voltage or the current output being a function of the switch off time divided by the switch on time.

Abstract: A series resonant inductive pickup has a bi-directional solid state switch in series with an inductor and a capacitor is controlled by switch control elements capable of causing the switching elements to repetitively be in either an open or a closed state, so that by varying the closed: open ratio of the switch the time-averaged amount of power picked up by the power pickup can be controlled. Switch is controlled by output of a voltage comparing circuit. A reference voltage source provides a basis for comparison of some fraction of a supply voltage in order to cause the switch to operate. The magnitude of capacitance in relation to the current drawn by the load determines the repetition rate of ON or OFF commands to the switch. If the current drawn by the load tends to zero, the proportion of time during which the switch is open will tend to 100%.

Abstract: Apparatus for providing effective amounts of high-frequency AC power to a long primary trackway (1102), used for inductive power transfer includes transconductance-pi filters (1105) for deliberate mismatching; resulting in independence of current flow and track impedance. These cause the source (1101) to appear as a voltage source and the trackway to appear as a low reactance. Shorting the output (1106) cuts the connected trackway from power without harm. The filter can cause a voltage step-up so driving a longer track. Track termination apparatus is disclosed that acts as a short circuit at only the operating frequency while terminating the track at its characteristic impedance otherwise. Half-bridge and full-bridge power supplies (1101) are described for providing effective amounts of high-frequency AC power to a long primary trackway used for inductive power transfer.

Abstract: Secondary resonant pickup coils (102) used in loosely coupled inductive power transfer systems, with resonating capacitors (902) have high Q and could support large circulating currents which may destroy components. A current limit or “safety valve” uses an inductor designed to enter saturation at predetermined resonating currents somewhat above normal working levels. Saturation is immediate and passive. The constant-current characteristic of a loosely coupled, controlled pickup means that if the saturable section is shared by coupling flux and by leakage flux, then on saturation the current source is terminated in the saturated inductor, and little detuning from resonance occurs. Alternatively an external saturable inductor (1101, 1102) may be introduced within the resonant circuit (102 and 902), to detune the circuit away from the system frequency. Alternatively DC current may be passed through a winding to increase saturation of a saturable part of a core.

Abstract: An inductively powered lamp unit 806 is fixed onto a substrate and over a position where a primary inductive loop 803 is spread apart (as at 807). At such sites, a horizontal (or at least parallel to the surface of the substrate) component of alternating magnetic flux is available. The conductors of the loop 802-803 can be inserted in a slit 804 cut into the substrate. The spreading apart of the conductors may be ensured with a spreader 808. A power supply 801 may be a resonant supply operating at 40 kHz. The lamp unit 806 does use a resonant pickup coil which can be shorted so as to minimize coupling, and provide supply regulation. The lamp unit can be controlled by signals transmitted over the primary loop. Applications include roadway markers and fire escape egress indicators, and underwater lighting.

Abstract: An inductively powered lamp unit 806 is fixed onto a substrate and over a position where a primary inductive loop 803 is spread apart (as at 807). At such sites, a horizontal (or at least parallel to the surface of the substrate) component of alternating magnetic flux is available. The conductors of the loop 802-803 can be inserted in a slit 804 cut into the substrate. The spreading apart of the conductors may be ensured with a spreader 808. A power supply 801 may be a resonant supply operating at 40 kHz. The lamp unit 806 does use a resonant pickup coil which can be shorted so as to minimize coupling, and provide supply regulation. The lamp unit can be controlled by signals transmitted over the primary loop. Applications include roadway markers and fire escape egress indicators, and underwater lighting.

Abstract: Inductive power transfer across an extended gap (100) from a primary conductor (119) is provided by means of a resonant intermediate loop comprised of capacitor (118) with inductor (117) carrying a larger resonating current, that can in turn generate an inductive field to be collected by a pickup coil (120). This process and device find application in an electroluminescent advertising panel.