Inductive power supply and object detection method thereof

Abstract

This invention provides an inductive power supply that generates a resonant signal when a resonant capacitor resonates with a power supply coil. A drive unit outputs a drive signal to drive the power supply coil. A voltage detector receives the resonant signal and converts it into a detection signal. A processor controls the drive unit and, when the resonant capacitor and power supply coil resonate, obtains the resonant period of the resonant signal based on the detection signal. After the drive unit drives the power supply coil, the resonant capacitor and power supply coil resonate, and the processor's timer starts counting. When the resonant period exceeds a period threshold, the timer stops counting, and the processor calculates the measurement duration from the start of the timer to its stop. If the measurement duration is less than a preset duration, the processor determines that an object exists within the power transmission range of the power supply module.

Claims

1. An inductive power supply, comprising: a power supply module including a power supply coil; and a resonant capacitor electrically connected to a first terminal of the power supply coil, wherein... The first end of the power supply coil has a node between it and the resonant capacitor, and the power supply coil and the resonant capacitor form a resonant circuit. When the resonant capacitor and the power supply coil resonate, a resonant signal is generated. A driving unit is electrically connected to the resonant capacitor and outputs a driving signal to drive the power supply coil. A voltage detector is electrically connected to the node to receive the resonant signal and convert the resonant signal into a detection signal. The system also includes a processor electrically connected to the voltage detector and the drive unit. The processor controls the drive unit and, when the resonant capacitor resonates with the power supply coil, acquires a resonant period of the resonant signal based on the detection signal. When the drive unit drives the power supply coil, the resonant capacitor resonates with the power supply coil, and a timer of the processor starts timing. When the resonant period exceeds a period threshold, the timer stops timing. The processor calculates a measurement duration from the start of the timer to the stop of timing. When the measurement duration is less than a preset duration, the processor determines that an object exists within the power transmission range of the power supply module.

2. As in the inductive power supply of request item 1, wherein, When the measurement duration exceeds the preset duration, the processor determines that the object does not exist within the power transmission range of the power supply module.

3. As in the inductive power supply of request item 1, wherein, The resonant capacitor has a resonant frequency when it resonates with the power supply coil, and the resonant frequency corresponds to the preset duration.

4. As in the inductive power supply described in claim 3, wherein, The processor records the maximum and minimum values ​​of the resonant signal during the timing process, and obtains a variation value based on the maximum and minimum values. When the measurement duration is less than the preset duration and the variation value is greater than a preset variation value, the processor determines that the object within the power transmission range of the power supply module is a power receiving device. When the measurement duration is less than the preset duration and the variation value is less than the preset variation value, the processor determines that the object within the power transmission range of the power supply module is a metallic foreign object. The power receiving device receives power from the power supply module.

5. As in the inductive power supply described in claim 4, wherein, The resonant frequency corresponds to the preset variation value, and the capacitance value of the resonant capacitor affects the resonant frequency.

6. The inductive power supply as claimed in claim 1 further includes a plurality of the resonant capacitors and a plurality of driving units, wherein, Each resonant capacitor is electrically connected to the corresponding drive unit. Each resonant capacitor and the corresponding drive unit are electrically connected between the processor and the first terminal of the power supply coil. Each resonant capacitor is electrically connected to the node. The processor controls at least one drive unit to output the drive signal to the corresponding resonant capacitor, so that the corresponding resonant capacitor resonates with the power supply coil and generates the resonant signal.

7. As in the inductive power supply of claim 6, wherein, When the corresponding resonant capacitor resonates with the power supply coil, it has a resonant frequency, and the resonant frequency corresponds to the preset duration.

8. A method for detecting an object in an inductive power supply, applicable to the inductive power supply of claim 1, wherein the method comprises the steps of: (a) when the driving unit drives the power supply coil, resonating the resonant capacitor and the power supply coil to generate the resonant signal, and controlling the timer of the processor to start timing; (b) receiving the resonant signal using the voltage detector and converting the resonant signal into the detection signal; (c) when the resonant period exceeds the period threshold, controlling the timer to stop timing; (d) calculating the measurement duration from the start of timing to the stop of timing using the processor; and (e) determining that an object exists within the power transmission range of the power supply module when the measurement duration is less than the preset duration.

9. The object detection method for the inductive power supply as described in claim 8, wherein, When the resonant capacitor resonates with the power supply coil, it has a resonant frequency, and the resonant frequency corresponds to the preset duration. The capacitance value of the resonant capacitor affects the resonant frequency.

10. The object detection method for the inductive power supply as described in claim 8 further includes the step of: (f) determining that the object does not exist within the power transmission range of the power supply module when the measurement duration is longer than the preset duration.

11. The object detection method for the inductive power supply as described in claim 10, wherein, The step (e) further includes the following steps: (g) using the processor to record a maximum value and a minimum value of the resonant signal during the timing process, and obtaining a variation value based on the maximum value and the minimum value; and (h) determining whether the variation value is greater than a preset variation value.

12. The object detection method for the inductive power supply of claim 11, wherein step (h) further comprises the steps of: (h1) if the determination result of step (h) is yes, using the processor to determine that the object within the power transmission range of the power supply module is a power receiving device, and executing step (i) after executing step (h1); (h2) if the determination result of step (h) is no, using the processor to determine that the object within the power transmission range of the power supply module is a metallic foreign object, and prohibiting the power transmission of the power supply module; and (i) allowing the power transmission of the power supply module.

13. The object detection method for the inductive power supply as described in claim 12, wherein, The inductive power supply also includes a plurality of resonant capacitors and a plurality of drive units, wherein step (a) further includes the steps of: (a1) controlling at least one drive unit to output the drive signal to the corresponding resonant capacitor, so that the corresponding resonant capacitor resonates with the power supply coil to generate the resonant signal, and controlling the timer of the processor to start counting at the start time.

14. The object detection method for the inductive power supply as described in claim 13, wherein, The procedure following steps (f) and (h1) further includes the following step: (k) determining whether the combination of the plurality of resonant capacitors has resonated with the power supply coil to generate the resonant signal. If the determination result of step (k) is yes, step (i) is executed; if the determination result of step (k) is no, step (a1) is executed. The combination of the plurality of resonant capacitors is composed of the resonant states of the plurality of resonant capacitors.

15. The object detection method for the inductive power supply as described in claim 14, wherein, The at least one resonant capacitor has a resonant frequency when it resonates with the power supply coil, and the resonant frequency corresponds to the preset duration.

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