Method of and apparatus for detecting coil alignment error in wireless inductive power transmission
First Claim
1. An apparatus for detecting coil alignment error in a wireless resonant inductive power transmission system comprising a primary inductive coil and a secondary inductive coil arranged to constitute a loosely coupled air core transformer whereby power in the primary inductive coil is transferred to the secondary inductive coil when the primary inductive coil is activated, comprising:
- at least two arc segment eddy current coils superimposed on the primary inductive coil, said at least two arc segment eddy current coils arranged to correspond with respective sectors of the primary inductive coil whereby an active eddy current coil has the effect of reducing a magnetic flux intercepted by the secondary inductive coil;
a switch connected to each arc segment eddy current coil;
a sequencer arranged to selectively activate the switch connected to each arc segment eddy current coil singularly or in unison in a switching sequence; and
a voltage detector that detects voltage variations in the secondary inductive coil during said switching sequence, whereby alignment of said primary inductive coil and said secondary inductive coil is detected by activating the eddy current coils sequentially and measuring detected voltage variations of the secondary inductive coil during the eddy current coil switching sequence, and whereby correspondence between the eddy current coil switching sequence and a largest magnetic flux variation of said secondary inductive coil indicates an error vector direction and a magnitude of magnetic flux variations of the secondary inductive coil indicate an error vector magnitude.
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Accused Products
Abstract
A method for detecting induction coil alignment error in resonant induction wireless power apparatus includes an eddy current coil array superimposed upon the primary induction coil, a switching device for each eddy current coil, a voltage detector such as a low power rectifier connected to the secondary induction coil, an analog-to-digital converter, primary and secondary side micro-controllers, and, in a vehicle charging embodiment, a vehicle operator interface. During coil alignment, the primary side induction coil operates at low power. Eddy current flows in an eddy current coil only if the associated switching device is switched on.
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Citations
22 Claims
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1. An apparatus for detecting coil alignment error in a wireless resonant inductive power transmission system comprising a primary inductive coil and a secondary inductive coil arranged to constitute a loosely coupled air core transformer whereby power in the primary inductive coil is transferred to the secondary inductive coil when the primary inductive coil is activated, comprising:
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at least two arc segment eddy current coils superimposed on the primary inductive coil, said at least two arc segment eddy current coils arranged to correspond with respective sectors of the primary inductive coil whereby an active eddy current coil has the effect of reducing a magnetic flux intercepted by the secondary inductive coil; a switch connected to each arc segment eddy current coil; a sequencer arranged to selectively activate the switch connected to each arc segment eddy current coil singularly or in unison in a switching sequence; and a voltage detector that detects voltage variations in the secondary inductive coil during said switching sequence, whereby alignment of said primary inductive coil and said secondary inductive coil is detected by activating the eddy current coils sequentially and measuring detected voltage variations of the secondary inductive coil during the eddy current coil switching sequence, and whereby correspondence between the eddy current coil switching sequence and a largest magnetic flux variation of said secondary inductive coil indicates an error vector direction and a magnitude of magnetic flux variations of the secondary inductive coil indicate an error vector magnitude. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of detecting of coil alignment error in a wireless resonant inductive power transmission system comprising a primary inductive coil and a secondary inductive coil arranged to constitute a loosely coupled air core transformer whereby power in the primary inductive coil is transferred to the secondary inductive coil when the primary inductive coil is activated, comprising the steps of:
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arranging at least two arc segment eddy current coils so as to be superimposed on the primary inductive coil and to correspond with respective sectors of the primary inductive coil; selectively activating said arc segment eddy current coils singularly or in unison in a switching sequence, whereby an active eddy current coil has the effect of reducing a magnetic flux intercepted by the secondary inductive coil; detecting variations of a detected voltage of the secondary inductive coil during said switching sequence; and detecting alignment of said primary inductive coil and said secondary inductive coil by activating the eddy current coils sequentially and measuring detected voltage variations of the secondary inductive coil during the eddy current coil switching sequence, whereby correspondence between the eddy current coil switching sequence and a largest magnetic flux variation of said secondary inductive coil indicates an error vector direction and a magnitude of magnetic flux variations of the secondary inductive coil indicate an error vector magnitude. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification