False notification suppression in wireless power transfer system
A power transmitter for wireless power transfer includes a sensing system, a feedback mechanism and a control and communications unit includes a controller configured to receive object detection data from the sensing system, if a power receiver is detected, reset an alert timer, if the power receiver has been detected and a disconnect is detected, determine if an alert timer value is greater than an alert threshold, if a disconnect is detected and the alert timer value is greater than the alert threshold, instruct the feedback mechanism to output an alert. The power transmitter further includes an inverter circuit configured to receive a direct current (DC) power and convert the input power to a power signal and a coil configured to transmit the power signal to a power receiver, the coil formed of wound Litz wire and including at least one layer, the coil defining, at least, a top face.
1. A power transmitter for wireless power transfer at an operating frequency, the power transmitter comprising:
a sensing system;
a feedback mechanism;
an inverter circuit configured to receive a direct current (DC) power and convert the DC power to a power signal;
a coil configured to transmit the power signal to a power receiver, the coil formed of wound Litz wire and including at least one layer, the coil defining, at least, a top face; and
a controller comprising:
at least one processor;
at least one machine-readable medium; and
program instructions stored on the at least one machine-readable medium which, when executed by the at least one processor, cause the controller to:
provide power control signals to control a power level of the power signal configured for transmission to the power receiver;
monitor the sensing system for object detection data indicative of near field magnetic coupling (NFMC) connectivity with the power receiver;
determine, based on the NFMC connectivity, that the power receiver is detected;
based on determining the power receiver is detected, reset an alert timer;
based on determining the power receiver is detected, instruct the inverter circuit to provide the power signal to the coil;
determine, based on the NFMC connectivity, that an NFMC disconnect is detected after the power receiver is detected;
based on determining the NFMC disconnect is detected, determine an alert timer value for the alert timer;
determine the alert timer value is greater than or less than an alert threshold for the alert timer;
based on determining the NFMC disconnect is detected and the alert timer value is greater than the alert threshold, instruct the feedback mechanism to output an alert indicative of the NFMC disconnect;
based on determining the NFMC disconnect is detected and the alert timer value is greater than the alert threshold, instruct the inverter circuit to cease providing the power signal to the coil; and
based on determining the NFMC disconnect is detected and the alert timer value is less than the alert threshold, continue to instruct the inverter circuit to provide the power signal to the coil.
2. The power transmitter of claim 1 , wherein the controller further comprises program instructions stored on the at least one machine-readable medium that are executable by the at least one processor such that the controller is configured to:
based on determining the NFMC disconnect is detected and the alert timer value is less than the alert threshold, do not instruct the feedback mechanism to output the alert indicative of the NFMC disconnect.
3. The power transmitter of claim 1 , wherein the controller further comprises program instructions stored on the at least one machine-readable medium that are executable by the at least one processor such that the controller is configured to:
determine if the object detection data re-indicates the NFMC connectivity with the power receiver after the NFMC disconnect is detected; and
if the object detection data re-indicates the NFMC connectivity with the power receiver after the NFMC disconnect is detected, reset the alert timer.
4. The power transmitter of claim 1 , wherein the feedback mechanism is configured for aiding a user in aligning the power receiver with an active area for wireless power transmission via the coil.
5. The power transmitter of claim 4 , wherein the feedback mechanism includes a visual feedback display configured to indicate proper alignment of the power receiver with the active area.
6. The power transmitter of claim 1 , wherein the feedback mechanism includes at least one light emitting diode (LED) configured to visually alert a user when the power receiver is detected.
7. The power transmitter of claim 6 , wherein the at least one LED is further configured to visually alert the user when the power receiver is disconnected and the alert timer value exceeds the alert threshold.
8. The power transmitter of claim 1 , further comprising a shielding having a cavity, wherein the shielding is an E-Core type shielding and the cavity is configured in an E-shape configuration.
9. The power transmitter of claim 8 , wherein a shielding outer edge of the shielding extends about 4.5 millimeters (mm) to about 6.5 mm outward from a coil outer edge of the coil.
10. The power transmitter of claim 1 , wherein the operating frequency is selected from a range of about 87 kilohertz (kHz) to about 205 kHz.
11. The power transmitter of claim 1 , wherein the power receiver is operatively associated with a wearable electronic device.
12. A system for wireless power transfer at an operating frequency, the system comprising:
a sensing system;
a feedback mechanism;
an inverter circuit configured to receive a direct current (DC) power and convert the DC power to a power signal;
a coil configured to transmit the power signal to a power receiver, the coil formed of wound Litz wire and including at least one layer, the coil defining, at least, a top face; and
a controller comprising:
at least one processor;
at least one machine-readable medium; and
program instructions stored on the at least one machine-readable medium which, when executed by the at least one processor, cause the controller to:
provide power control signals to control a power level of the power signal configured for transmission to the power receiver;
monitor the sensing system for object detection data indicative of near field magnetic coupling (NFMC) connectivity with the power receiver;
determine, based on the NFMC connectivity, that the power receiver is detected;
based on determining the power receiver is detected, reset an alert timer;
based on determining the power receiver is detected, instruct the inverter circuit to provide the power signal to the coil;
determine, based on the NFMC connectivity, that an NFMC disconnect is detected after the power receiver is detected;
based on determining the NFMC disconnect is detected, determine an alert timer value for the alert timer;
determine the alert timer value is greater than or less than an alert threshold for the alert timer;
based on determining the NFMC disconnect is detected and the alert timer value is greater than the alert threshold, instruct the feedback mechanism to output an alert indicative of the NFMC disconnect;
based on determining the NFMC disconnect is detected and the alert timer value is greater than the alert threshold, instruct the inverter circuit to cease providing the power signal to the coil; and
based on determining the NFMC disconnect is detected and the alert timer value is less than the alert threshold, continue to instruct the inverter circuit to provide the power signal to the coil.
13. The system of claim 12 , wherein the feedback mechanism is configured for aiding a user in aligning the power receiver with an active area for wireless power transmission via the coil.
14. The system of claim 13 , wherein the feedback mechanism includes at least one light emitting diode (LED) configured to visually alert a user when the power receiver is detected.
15. The system of claim 14 , wherein the at least one LED is further configured to visually alert the user when the power receiver is disconnected and the alert timer value exceeds the alert threshold.
16. The system of claim 13 , wherein the feedback mechanism includes a visual feedback display configured to indicate proper alignment of the power receiver with the active area.
17. The system of claim 12 , wherein the controller further comprises program instructions stored on the at least one machine-readable medium that are executable by the at least one processor such that the controller is configured to:
based on determining the NFMC disconnect is detected and the alert timer value is less than the alert threshold, do not instruct the feedback mechanism to output the alert indicative of the NFMC disconnect.
18. The system of claim 12 , wherein the controller further comprises program instructions stored on the at least one machine-readable medium that are executable by the at least one processor such that the controller is configured to:
determine if the object detection data re-indicates the NFMC connectivity with the power receiver after the NFMC disconnect is detected; and
if the object detection data re-indicates the NFMC connectivity with the power receiver after the NFMC disconnect is detected, reset the alert timer.
19. The system of claim 12 , wherein the power receiver is operatively associated with a wearable electronic device.
20. The system of claim 12 , wherein operating frequency is selected from a range of about 87 kilohertz (kHz) to about 205 kHz.