Method for power calibration

A method of calibrating a power measuring function of a wireless power device, the method comprising:

• feeding an alternating electric signal through a wireless power transmitter coil to drive the wireless power transmitter coil at an operating point;
• performing voltage measurements and current measurements upon said alternating electric signal or upon a current signal resulting therefrom in the wireless power device;
• producing a series of voltage values and a series of current values from the voltage measurements and current measurements;
• calculating a power value from the produced series of voltage values and series of current values;
• assessing whether the calculated power value meets a specification;
• if not, introducing a compensatory change in either of the produced series of voltage values and series of current values to account for a phase shift between the voltage measurements and current measurements at said operating point;
• and
• storing the compensatory change for the wireless power device, thereby enabling the power measuring function thereof to produce wireless power measurement results at said operating point which are consistent with said specification,
• wherein:
• the wireless power device is a wireless power receiver device with a wireless power receiver coil comprised in, galvanically coupled to or otherwise associated therewith,
• the wireless power transmitter coil is comprised in, galvanically coupled to or otherwise associated with a wireless power transmitter device,
• the feeding step is performed by the wireless power transmitter device,
• all other steps of the method are performed by the wireless power receiver device,
• the voltage measurements and current measurements are performed upon a resulting alternating electric signal received through the wireless power receiver coil of the wireless power receiver device in response to said alternating electric signal being fed through the wireless power transmitter coil, and
• assessing whether the calculated power value meets the specification involves assessing whether it falls within a specified error margin from a transmitted power value determined by the wireless power transmitter device.

A method of calibrating a power measuring function of a wireless power device, the method comprising:

• feeding an alternating electric signal through a wireless power transmitter coil to drive the wireless power transmitter coil at an operating point;
• performing voltage measurements and current measurements upon said alternating electric signal or upon a current signal resulting therefrom in the wireless power device;
• producing a series of voltage values and a series of current values from the voltage measurements and current measurements;
• calculating a power value from the produced series of voltage values and series of current values;
• assessing whether the calculated power value meets a specification;
• if not, introducing a compensatory change in either of the produced series of voltage values and series of current values to account for a phase shift between the voltage measurements and current measurements at said operating point;
• and
• storing the compensatory change for the wireless power device, thereby enabling the power measuring function thereof to produce wireless power measurement results at said operating point which are consistent with said specification,
• wherein the method further comprises introductory steps of:
• independently assessing the ability of the power measuring function of the wireless power device to determine RMS voltage values and RMS current values at a specified accuracy;
• and
• if necessary, calibrating the power measuring function of the wireless power device.