US 2013/0154373 A1 · PRIMARY UNIT CONTROL OF RESONANT INDUCTIVE POWER TRANSFER SYSTEM FOR OPTIMUM EFFICIENCY

Abstract

A circuit and method for wirelessly coupling an electrical energy between an electrical energy source and at least one load is provided. The circuit comprises a primary unit and at least one secondary unit. The primary unit includes an input node for receiving an input voltage produced by the energy source; a transmitter circuit including a transmitter coil configured to generate an electromagnetic field; and a regulator. The regulator is configured to sense a current consumption of the primary unit, determine a gradient of the current consumption with respect to different input voltages, and determine an optimal input voltage based on the gradient. The at least one secondary unit comprises a receiver circuit and a load. The receiver unit includes a coil that wirelessly and inductively couples with the electromagnetic field of the primary unit to receive power therefrom. The receiver unit further includes a regulator circuit configured to provide a constant power to an output node.

Claims23

Dependent claims

A circuit for wirelessly coupling electrical energy between an electrical energy source and at least one load, comprising:

a primary unit comprising:
an input node for receiving an input voltage produced by the energy source;
a transmitter circuit including a transmitter coil configured to generate an electromagnetic field;
and
a regulator configured to:
sense a current consumption of the primary unit,
determine a gradient of the current consumption with respect to different input voltages, and
determine an optimal input voltage based on the gradient of the current consumption of the primary unit with respect to different input voltages;
and
at least one secondary unit, each secondary unit comprising:
a receiver circuit including:
a receiver coil to wirelessly and inductively couple with the electromagnetic field of the primary unit to receive power therefrom;
a regulator circuit configured to provide a constant power to an output node;
and
a load coupled to the output node.

12 more elements

A method for controlling electrical wireless power transfer in an electrical power transfer system comprising a primary unit configured to generate an electromagnetic field and at least one secondary unit configured to couple with the electromagnetic field and provide a regulated output voltage to its respective load, the method comprising:

ramping an input voltage in the primary unit in a first direction;
sensing a current consumption in the primary unit at predetermined input voltage steps;
storing a current consumption for each input voltage in a memory;
calculating a gradient of the current consumption with respect to input voltage for each voltage step;
recording the gradient of the current consumption for each voltage step in the memory;
comparing the gradient between each voltage step to a predetermined first threshold;
determining an optimal input voltage in the primary unit, wherein an optimal input voltage is at an input voltage where the gradient is equal to or less than the predetermined first threshold.

4 more elements

in step 1:
setting an input voltage in the primary unit to a predetermined Vmin value;
increasing the input voltage by a predetermined voltage step;
sensing a current consumption in the primary unit at each input voltage value;
and
storing the current consumption at each input voltage value in a memory;
in step 2:
calculating a gradient of the current consumption with respect to input voltage for the voltage step;
and
storing the gradient as a present-gradient in a memory;
in step 3:
comparing the present-gradient to a first reference gradient;
if the present-gradient is less than or equal to the first reference gradient, then keeping the input voltage fixed for a predetermined delay period;
and going back to step 1 after an expiration of the predetermined delay period;
if the present-gradient is greater than the first reference gradient, then going to step 4;
in step 4:
changing the input voltage in the primary unit to a predetermined Vmax value minus the predetermined voltage step, wherein the predetermined Vmax value is higher than the predetermined Vmin value;
increasing the input voltage by the predetermined voltage step;
sensing a current consumption in the primary unit at each input voltage value;
storing the current consumption for each input voltage value in a memory;
calculating a gradient of the current consumption with respect to input voltage for the voltage step;
and
storing the gradient of the current consumption as the present-gradient in a memory;
in step 5:
comparing the present-gradient to the first reference gradient;
if the present-gradient is greater than the first reference gradient, then:
setting the input voltage to Vmax;
keeping the input voltage fixed at Vmax for the predetermined delay period;
and
upon expiration of the delay period, going back to step 1;
if the present-gradient is less than or equal to the first reference gradient, then:
storing the present gradient as the minimum reference gradient setting a Vlow to Vmin and Vhigh to Vmax;
and
continuing with step 6;
in step 6:
changing the input voltage in the primary unit to (Vlow+Vhigh)/2,
increasing the input voltage by the predetermined voltage step;
sensing a current consumption in the primary unit at each input voltage value;
storing the current consumption at each input voltage value in a memory;
calculating a gradient of the current consumption with respect to input voltage for the voltage step;
and
storing the gradient as a present-gradient in a memory;
in step 7:
calculating a gradient of the current consumption with respect to input voltage for the voltage step;
and
storing the gradient as a present-gradient in a memory;
in step 8:
comparing the present-gradient to the first reference gradient and a minimum reference gradient;
if the present-gradient is greater than the minimum reference gradient, and less than or equal to the first reference gradient, then going to step 10;
otherwise, going to step 9;
in step 9:
if the present-gradient is greater than the first reference gradient, then setting the Vlow to the present input voltage of the primary unit;
if the present-gradient is less than or equal to the minimum reference gradient, then setting Vhigh to the present input voltage of the primary unit;
and
repeating steps 6 to 8;
in step 10:
keeping the input voltage fixed for the predetermined delay period;
and
after an expiration of the predetermined delay period, repeating the method by going back to step 1.

56 more elements

Dependencies are inferred from the claim text.

Primary unit control of resonant inductive power transfer system for optimum efficiency

Life of this patent

Primary unit control of resonant inductive power transfer system for optimum efficiency

Life of this patent

Abstract

Claims23