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Inductively coupled power transfer system and device

  • US 9,396,869 B2
  • Filed: 07/23/2013
  • Issued: 07/19/2016
  • Est. Priority Date: 07/24/2012
  • Status: Active Grant
First Claim
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1. An inductively coupled power transfer (ICPT) system comprising:

  • a primary winding for generating an electromagnetic field in response to an alternating current (AC); and

    a contactless ICPT device includinga phase detecting winding which generates a detecting voltage according to induction of the electromagnetic field,a resonant circuit which has an adjustable reactance that is associated with a resonant frequency of said resonant circuit, and which is adapted to generate an AC voltage according to induction of the electromagnetic field and the adjustable reactance for supplying an output voltage associated with the AC voltage to a load, anda control circuit which is coupled electrically to said phase detecting winding and said resonant circuit and to be coupled electrically to the load, which compares a phase of the AC voltage with a phase of the detecting voltage so as to determine whether said resonant circuit operates in an under-tuned interval, where the output voltage monotonically decreases along with an increase in the resonant frequency, or an over-tuned interval, where the output voltage monotonically increases along with an increase in the resonant frequency, and which varies the adjustable reactance according to at least the output voltage and one of the under-tuned interval and the over-tuned interval in which said resonant circuit operates, for control of the output voltage;

    wherein said control circuit includes;

    a switching controller including a first control unit and a second control unit, each of which is to be coupled electrically to the load for detecting the output voltage across the load, and is triggered to control said resonant circuit which operates in a respective one of the under-tuned interval and the over-tuned interval so as to generate adjustment information associated with the output voltage, the adjustment information being to serve as a basis for varying the adjustable reactance, andan operation interval discriminator coupled electrically to said switching controller, and to said phase detecting winding and said resonant circuit for detecting respectively the detecting voltage and the AC voltage, and generating an operation interval indication signal according to a phase difference, which changes along with the adjustable reactance, between the detecting voltage and the AC voltage, so as to trigger one of said first and second control units based on the operation interval indication signal.

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