Systems and methods of reduction of parasitic losses in a wireless power system
First Claim
1. A method comprising:
- transferring power from a transmitter to a receiver in a wireless power system;
measuring input power to the transmitter;
receiving a message from the receiver indicating power received at the receiver;
determining an amount of power lost in the transferring to indicate a presence of a parasitic loss in the wireless power system;
determining a portion of the transferred power attributed to parasitic loss in a foreign object;
reducing the power transmitted from the transmitter to a non-zero level so that the portion of transferred power lost in the foreign object does not exceed a predetermined safe level; and
ignoring messages from the receiver requesting a higher level of transmitted power, wherein the presence of a parasitic loss is determined by comparing measured losses to expected losses, the expected losses determined by measuring system characteristics in a controlled environment, by applying a mathematical fit of the system characteristics to an equation for predicting parasitic losses, wherein the equation calculates expected loss as the sum of;
a first constant multiplied by the square of transmitter peak voltage;
a second constant multiplied by the transmitter peak voltage; and
a third constant.
1 Assignment
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Accused Products
Abstract
Example embodiments of the systems and methods of reduction of parasitic losses in a wireless power system disclosed herein provide a practical means of accurately estimating parasitic losses in a wireless power transfer system irrespective of coupling. Such systems and methods may be used to generate an equation which predicts parasitic losses in a wireless power system. In an offset case, in which the transmitter and receiver are not directly coupled, losses associated with the recirculating current in the primary LC tank dominate the loss, and the transmitted power may be better estimated by measuring the power inputs, power outputs, and injected losses in a controlled environment; making a mathematical fit to an equation, which from the various power measurements and injected loss, predicts the expected transmitter losses; and then, in an operational environment, using the equation to predict parasitic losses based on the power inputs, power outputs and expected loss equation.
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Citations
15 Claims
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1. A method comprising:
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transferring power from a transmitter to a receiver in a wireless power system; measuring input power to the transmitter; receiving a message from the receiver indicating power received at the receiver; determining an amount of power lost in the transferring to indicate a presence of a parasitic loss in the wireless power system; determining a portion of the transferred power attributed to parasitic loss in a foreign object; reducing the power transmitted from the transmitter to a non-zero level so that the portion of transferred power lost in the foreign object does not exceed a predetermined safe level; and ignoring messages from the receiver requesting a higher level of transmitted power, wherein the presence of a parasitic loss is determined by comparing measured losses to expected losses, the expected losses determined by measuring system characteristics in a controlled environment, by applying a mathematical fit of the system characteristics to an equation for predicting parasitic losses, wherein the equation calculates expected loss as the sum of; a first constant multiplied by the square of transmitter peak voltage; a second constant multiplied by the transmitter peak voltage; and a third constant. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method comprising:
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transferring power from a transmitter to a receiver in a wireless power system; measuring input power to the transmitter; receiving a message from the receiver indicating power received at the receiver; determining an amount of power lost in the transferring to indicate a presence of a parasitic loss in the wireless power system; determining a portion of the transferred power attributed to parasitic loss in a foreign object; reducing the power transmitted from the transmitter to a non-zero level so that the portion of transferred power lost in the foreign object does not exceed a predetermined safe level; and ignoring messages from the receiver requesting a higher level of transmitted power, wherein the presence of a parasitic loss is determined by comparing measured losses to expected losses, the expected losses determined by measuring system characteristics in a controlled environment, by applying a mathematical fit of the system characteristics to an equation for predicting parasitic losses, wherein the equation calculates expected loss as the sum of; a first constant multiplied by the square of transmitter peak voltage; a second constant multiplied by the transmitter peak voltage; a third constant; and a fourth constant multiplied by input current.
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8. A system comprising:
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a transmitter in a wireless power system configured to; transmit power to a receiver; measuring input power to the transmitter; receiving a message from the receiver indicating power received at the receiver; determining the presence of a parasitic loss in the wireless power system; determining a portion of the transferred power attributed to parasitic loss in a foreign object; reduce the power transmitted to a non-zero level so that the portion of transferred power lost in the foreign object does not exceed a predetermined safe level; and ignoring messages from the receiver requesting a higher level of transmitted power, wherein the presence of a parasitic loss is determined by comparing measured losses to expected losses, the expected losses determined by measuring system characteristics in a controlled environment, by applying a mathematical fit of the system characteristics to an equation for predicting parasitic losses, wherein the equation calculates expected loss as the sum of; a first constant multiplied by the square of transmitter peak voltage; a second constant multiplied by the transmitter peak voltage; a third constant; and a fourth constant multiplied by input current. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A system comprising:
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a transmitter in a wireless power system configured to; transmit power to a receiver; measuring input power to the transmitter; receiving a message from the receiver indicating power received at the receiver; determining the presence of a parasitic loss in the wireless power system; determining a portion of the transferred power attributed to parasitic loss in a foreign object; reduce the power transmitted to a non-zero level so that the portion of transferred power lost in the foreign object does not exceed a predetermined safe level; and ignoring messages from the receiver requesting a higher level of transmitted power, wherein the presence of a parasitic loss is determined by comparing measured losses to expected losses, the expected losses determined by measuring system characteristics in a controlled environment, by applying a mathematical fit of the system characteristics to an equation for predicting parasitic losses wherein the equation calculates expected loss as the sum of; a first constant multiplied by the square of transmitter peak voltage; a second constant multiplied by the transmitter peak voltage and the transmitter input current; and a third constant.
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15. A system comprising:
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means for transmitting power to a receiver; means for measuring input power to the transmitter; means for receiving a message from the receiver indicating power received at the receiver; means for determining the presence of a parasitic loss in the wireless power system; means for determining a portion of the transferred power attributed to parasitic loss in a foreign object; means for reducing the power transmitted to a non-zero level so that the portion of transferred power lost in the foreign object does not exceed a predetermined safe level; and means for ignoring messages from the receiver requesting a higher level of transmitted power;
further comprising means for determining the presence of a parasitic loss by comparing measured losses to expected losses, the expected losses determined by measuring system characteristics in a controlled environment, by applying a mathematical fit of the system characteristics to an equation for predicting parasitic losses, wherein the equation calculates expected loss as the sum of;a first constant multiplied by the square of transmitter peak voltage; a second constant multiplied by the transmitter peak voltage; and a third constant.
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Specification