Abstract: A method of operating an electric vehicle charging apparatus for a vehicle to grid interface comprising a first full bridge converter configured to convert a grid supply to a DC link and a primary full bridge converter connected to the DC link and configured to provide an output alternating current for use in vehicle charging. The method includes detecting a charging power requirement for a vehicle; determining a required voltage for the DC link to enable the converter to supply power for satisfying the charging power requirement when operating at full duty cycle; operating the primary full bridge converter at full duty cycle; controlling the voltage of the DC link to the required voltage.

Abstract: A method of controlling the primary or secondary side converter of a wireless power transfer (WPT) or an inductive power transfer (IPT) system includes optimising a load impedance, and controlling one or more of a duty cycle or relative phase angle to reduce or minimize the converter losses at the optimal load impedance

Abstract: A converter including a bridge circuit having a first leg and a second leg, each leg including a high switch and a low switch, the high switches being connected to a first energy source and the low switches being connected to ground, a coupling network(s) having a first connection between the switches of the first leg and a second connection between the switches of the second leg, and a second (or multiple secondary) energy source(s) connected between the coupling network(s) and ground, wherein the coupling network comprises a first inductive element connected between the second energy source and the switches of the first leg, and a second inductive element connected between the second energy source and the switches of the second leg.

Abstract: A method of operating an electric vehicle charging apparatus for a vehicle to grid interface comprising a first full bridge converter configured to convert a grid supply to a DC link and a primary full bridge converter connected to the DC link and configured to provide an output alternating current for use in vehicle charging. The method includes detecting a charging power requirement for a vehicle; determining a required voltage for the DC link to enable the converter to supply power for satisfying the charging power requirement when operating at full duty cycle; operating the primary full bridge converter at full duty cycle; controlling the voltage of the DC link to the required voltage.

Abstract: A polyphase inductive power transfer system primary or secondary apparatus includes a magnetic coupling coil associated with each phase and a compensation network associated with each magnetic coupling coil for providing power to or receiving power from the respective coil. At least one of the compensation networks has a different power transfer characteristic to one or more of the other compensation networks.

Abstract: An inductive power transfer (IPT) converter has a first switching means adapted to produce a time varying input power signal comprising a substantially unipolar stepped waveform, and a second switching means adapted to modify the time varying input power signal provided by the first switching means to produce a modified input power signal. The converter is coupled to a resonant circuit to receive the modified input signal.

Abstract: An inductive power transfer system primary or secondary circuit has a first compensation network and second compensation network. The compensation networks each have a different power transfer characteristic with respect to relative movement of the primary or secondary magnetic flux coupling structures. The power transfer characteristics are such that one compensates for the other to allow a smooth or constant overall power transfer is despite the relative movement.

Abstract: An IPT primary or secondary circuit includes a converter connected to a primary energy source and a compensation network. A supplementary energy source is connected to the compensation network and the converter transfers energy between the primary energy source or another IPT primary or secondary circuit and the supplementary energy source.

Abstract: An inductive power transfer system primary or secondary circuit has a first compensation network and second compensation network. The compensation networks each have a different power transfer characteristic with respect to relative movement of the primary or secondary magnetic flux coupling structures. The power transfer characteristics are such that one compensates for the other to allow a smooth or constant overall power transfer is despite the relative movement.

Abstract: The present invention relates to a AC-AC converter, which has particular relevance to a converter for an inductive or capacitive (wireless) power transfer system. More specifically, the current invention discloses an AC-AC converter comprising a bridge circuit having a first leg and a second leg, each leg including a high switch and a low switch, the high switches being connected to a first energy source and the low switches being connected to ground, a coupling network(s) having a first connection between the switches of the first leg and a second connection between the switches of the second leg, a second (or multiple secondary) energy source(s) connected between the coupling network(s) and ground.

Abstract: A polyphase inductive power transfer system primary or secondary apparatus includes a magnetic coupling coil associated with each phase and a compensation network associated with each magnetic coupling coil for providing power to or receiving power from the respective coil. At least one of the compensation networks has a different power transfer characteristic to one or more of the other compensation networks.

Abstract: A method is provided for controlling the output voltage of a pickup in an inductive power transfer (IPT) system without any additional form of communications for feedback from the pickup to the power supply. The method comprising the steps of deriving an estimate of the output voltage of the pickup from the voltage across the primary conductive path, and adjusting the current in the primary conductive path so that the estimated pickup output voltage matches a required pickup output voltage. In particular, an estimate of the pickup output voltage is derived from the magnitude and phase angle of the voltage in the primary conductive path.

Abstract: A method, apparatus, and system are provided which enables the control of contactless power transfer in an inductive power transfer system using a phase control technique. The method comprises adjusting the phase of a secondary-side converter output voltage with respect to that of a primary-side converter. The magnitude of power transfer is determined by the relative phase angle, and the direction of power transfer is determined by whether the secondary converter output voltage leads or lags the input converter voltage, thereby enabling bi-directional power transfer between the primary and secondary sides of the system. According to alternative embodiments, the method may also be used for uni-directional power transfer only, and/or the secondary converter may be operated to maintain a constant relative phase angle.

Abstract: The present invention provides a polyphase inductive power transfer (IPT) system comprising a primary power supply comprising a plurality of primary conductors, the primary conductors being individually selectively operable to provide or receive a magnetic field for inductive power transfer; and at least one pick-up comprising one or more pick-up conductors, the one or more pick-up conductors each being individually selectively operable to magnetically couple with a primary conductor to control power transfer between the primary power supply and a load coupled or coupleable with the respective pick-up. The polyphase primary power supply may be used to power a plurality of single-phase pick-ups, one or more polyphase pick-ups, or a combination thereof. Also disclosed are polyphase primary and secondary converters for use in such a system.

Abstract: A control method for use in a primary side power converter (1) of an inductive power transfer (IPT) system. The power transfer from the primary side to one or more secondary pick-ups is monitored, and the operating frequency of the primary side power converter (1) is varied in proportion to a difference between the monitored power transfer and a power capability of the primary side power converter. The frequency variation can be sensed by the or each pick-up (2) to regulate the power transfer and to prevent overloading from occurring.

Abstract: An IPT system for wireless power transfer is provided, in particular an IPT system capable of operating at high frequencies. In one aspect there is provided an IPT transmitter comprising a push-pull resonant converter having a resonant frequency and configured to operate at a switching frequency below the resonant frequency and dependent on a switching characteristic of a second converter configured to inductively couple to said transmitter.

Abstract: An inductive power transfer system primary or secondary circuit has a first compensation network and second compensation network. The compensation networks each have a different power transfer characteristic with respect to relative movement of the primary or secondary magnetic flux coupling structures. The power transfer characteristics are such that one compensates for the other to allow a smooth or constant overall power transfer is despite the relative movement.

Abstract: An IPT primary or secondary circuit includes a converter connected to a primary energy source and a compensation network. A supplementary energy source is connected to the compensation network and the converter transfers energy between the primary energy source or another IPT primary or secondary circuit and the supplementary energy source.

Abstract: An inductive power transfer OPT system) includes an AC-AC full-bridge converter (Tp1-Tp4) provided between the primary conductive path (Lpt) and an alternating current power supply (Vin). The system may include a controller for controlling the pick-up device to shape the input current drawn from the alternating current power supply (Vin).

Abstract: A control method for use in a primary side power converter (1) of an inductive power transfer (IPT) system. The power transfer from the primary side to one or more secondary pick-ups is monitored, and the operating frequency of the primary side power converter (1) is varied in proportion to a difference between the monitored power transfer and a power capability of the primary side power converter. The frequency variation can be sensed by the or each pick-up (2) to regulate the power transfer and to prevent overloading from occurring.