Foreign matter detection method and device for wireless power transmission system, home appliance and air conditioner

Abstract

The application discloses a foreign matter detection method and device of a wireless power transmission system; the wireless power transmission system comprises a transmitting end and a receiving end; the method comprises the following steps: controlling the transmitting end to send electric energy to the receiving end to charge an energy storage module of the receiving end; after charging the energy storage module to a target voltage, the output voltage of the transmitting end is reduced, and the transmitting power of the transmitting end is obtained; wherein, the energy storage module is discharged after the output voltage of the transmitting end is reduced, so that the receiving end does not receive the electric energy of the transmitting end; based on the transmitting power and a preset reference power, a foreign matter detection result is obtained; wherein, the reference power is the excitation power of the transmitting end after the output voltage of the transmitting end is reduced when the energy storage module is charged to the target voltage in a state without foreign matter. The method can be effectively applied to small metal foreign matter detection in a high-power wireless power transmission scene, and the detection accuracy is high.

Description

Technical Field

[0001] This invention belongs to the field of wireless power transmission, and particularly relates to a method and device for detecting foreign objects in wireless power transmission systems. Background Technology

[0002] Currently, wireless power transfer technology is becoming increasingly popular in various electronic products and electrical appliances because it eliminates the need for exposed contact points during transmission, making it more convenient to use. Wireless power transfer technology can be categorized into low-power and high-power wireless transmission. For high-power wireless power transfer, current methods, such as cameras and thermal imaging devices, are required to detect foreign objects between the coils. These detection methods, requiring additional devices or equipment, are not suitable for use in portable mobile devices. Therefore, there is an urgent need for a method or device for detecting metallic foreign objects that can be applied to high-power wireless power transmission scenarios. Summary of the Invention

[0003] This invention provides a method and apparatus for detecting foreign objects in a wireless power transmission system, which can be effectively applied to the detection of small metal foreign objects in high-power wireless power transmission scenarios with high detection accuracy.

[0004] In a first aspect, embodiments of the present invention provide a foreign object detection method for a wireless power transmission system, the wireless power transmission system including a transmitter and a receiver; the method includes: controlling the transmitter to send electrical energy to the receiver to charge an energy storage module of the receiver; after charging the energy storage module to a target voltage, reducing the output voltage of the transmitter to obtain the transmission power of the transmitter; wherein, the energy storage module discharges after reducing the output voltage of the transmitter, so that the receiver does not receive electrical energy from the transmitter; obtaining a foreign object detection result based on the transmission power and a preset reference power; wherein, the reference power is the excitation power of the transmitter after reducing the output voltage of the transmitter after charging the energy storage module to the target voltage in a foreign object-free state.

[0005] Optionally, the transmitting end includes a detection coil and a working coil, wherein the mutual inductance corresponding to the detection coil is greater than the mutual inductance corresponding to the working coil; the step of controlling the transmitting end to send electrical energy to the receiving end to charge the energy storage module of the receiving end to the target voltage includes: The detection coil at the transmitting end is controlled to send electrical energy to the receiving end to charge the energy storage module of the receiving end to the target voltage.

[0006] Optionally, the detection coil is wound in a disc shape, and the detection coil includes a first transmitting part and a second transmitting part, the first transmitting part and the second transmitting part are connected in series, and the second transmitting part is wrapped around the outside of the first transmitting part. One end of the transmitting detection coil is provided with a first transmitting end lead, and a second transmitting end lead is provided between the first transmitting part and the second transmitting part; before the detection coil of the transmitting end is controlled to transmit electrical energy to the receiving end, the method further includes: Disconnect the second transmitting lead and connect the first transmitting lead to disconnect the working coil and connect the detection coil to the circuit for operation.

[0007] Optionally, charging the energy storage module to the target voltage includes: The transmitter is controlled to send electrical energy to the receiver to charge the energy storage module; the voltage value of the energy storage module is monitored, and when the voltage of the energy storage module reaches the target voltage, the power of the transmitter is reduced so that the energy storage module is maintained at the target voltage.

[0008] Optionally, reducing the output voltage of the transmitter includes: The output voltage of the transmitting end is reduced by a preset voltage, wherein the preset voltage is not less than 1 / 4 of the standard output voltage; wherein the standard output voltage is used to maintain the voltage of the energy storage module at the target voltage when there are no foreign objects between the transmitting end and the receiving end.

[0009] Optionally, obtaining the foreign object detection result based on the transmission power and a preset reference power includes: Based on the reference power and the preset margin value, the comparison power is determined; based on the magnitude of the transmission power and the comparison power, the foreign object detection result is obtained; wherein, when the transmission power is greater than the comparison power, the foreign object detection result is determined to indicate the presence of a foreign object, otherwise the foreign object detection result is determined to indicate the absence of a foreign object.

[0010] Optionally, performing multiple foreign object detections on the wireless power transmission system, wherein obtaining the foreign object detection result based on the magnitude of the transmission power and the comparison power includes: Determine whether the transmission power is greater than the comparison power; if yes, determine that the foreign object detection result indicates the presence of a foreign object; if no, repeat the following steps: control the transmitter to send electrical energy to the receiver to charge the energy storage module of the receiver; after charging the energy storage module to the target voltage, reduce the output voltage of the transmitter and obtain the transmission power of the transmitter; obtain the foreign object detection result based on the transmission power and a preset reference power; until a foreign object detection result indicating the presence of a foreign object is obtained; or repeat the process for a preset number of times or a preset duration to obtain a foreign object detection result indicating the absence of a foreign object.

[0011] Secondly, embodiments of the present invention also provide a foreign object detection device for a wireless power transmission system, applied to the transmitting end of a wireless power transmission device; the device includes: a charging module, used to control the transmitting end to send electrical energy to the receiving end to charge the energy storage module of the receiving end to a target voltage; a step-down module, used to reduce the output voltage of the transmitting end and obtain the transmission power of the transmitting end; wherein, the energy storage module discharges after reducing the output voltage of the transmitting end, so that the receiving end does not receive the electrical energy of the transmitting end; a detection module, used to obtain a foreign object detection result based on the transmission power and a preset reference power; wherein, the reference power is the excitation power of the transmitting end after reducing the output voltage of the transmitting end when the energy storage module is charged to the target voltage in the absence of foreign objects.

[0012] Thirdly, embodiments of the present invention also provide a wireless power transmission device, comprising: a transmitter configured to wirelessly transmit electrical energy, a processor, and a memory; the memory is coupled to the processor, and the memory stores instructions that, when executed by the processor, cause the wireless power transmission device to perform the steps of any of the methods described in the first aspect above.

[0013] Fourthly, embodiments of the present invention also provide a home appliance, including: a receiving end; the receiving end is configured to receive electrical energy transmitted by a transmitting end to charge the energy storage module to a target voltage; the energy storage module of the receiving end is configured to discharge when the transmitting end reduces its output voltage, so that the receiving end does not receive electrical energy from the transmitting end; wherein, the transmitting end is used to acquire transmission power and obtain a foreign object detection result based on the transmission power and a preset reference power; the reference power is the excitation power of the transmitting end after charging the energy storage module to the target voltage and reducing the output voltage of the transmitting end when there is no foreign object.

[0014] Fourthly, embodiments of the present invention also provide an air conditioner, comprising: a receiver configured to wirelessly receive electrical energy, a processor, and a memory; the memory is coupled to the processor, and the memory stores instructions that, when executed by the processor, cause the wireless power transmission device to perform the steps of any of the methods described in the first aspect.

[0015] The one or more technical solutions provided in the embodiments of the present invention have at least the following effects or advantages: This invention provides a foreign object detection method for a wireless power transmission system. By charging the energy storage module, the voltage at the transmitting end is reduced to suppress the transmission of electrical energy from the transmitting end to the receiving end. This enables the detection of metallic foreign objects between the transmitting and receiving ends under low power conditions, improving detection accuracy and effectively applying it to the detection of small metallic foreign objects in high-power wireless power transmission scenarios. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a partial circuit structure diagram of a wireless power transmission system according to an embodiment of the present invention; Figure 2 This is a flowchart of a foreign object detection method for a wireless power transmission system in an embodiment of the present invention; Figure 3 This is a partial circuit structure diagram of another wireless power transmission system in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the first coil in an embodiment of the present invention; Figure 5 This is a schematic diagram showing the voltage state of the energy storage module at different detection stages in an embodiment of the present invention; Figure 6 This invention relates to a foreign object detection device for a wireless power transmission system of a home appliance. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0019] This embodiment provides a foreign object detection method for a wireless power transmission system. The method can be applied to a wireless power transmission system, which includes a transmitter and a receiver. For example, the transmitter can be installed in a wireless charger, and the receiver can be installed in a mobile phone, computer, home appliance, or other electrical device. Thus, the transmitter in the wireless charger and the receiver in the electrical device constitute a wireless power transmission system.

[0020] In some possible implementations, the transmitter may include a first bridge circuit and a first coil electrically connected to the first bridge circuit. See also... Figure 1 In some examples, the first bridge circuit of the transmitter mentioned above can be understood to include a first power device Q1, a second power device Q2, a third power device Q3, and a fourth power device Q4. The first power device Q1 and the third power device Q3 are connected in series to form a first branch, and the second power device Q2 and the fourth power device Q4 are connected in series to form a second branch. The first branch and the second branch are connected in parallel. The first end of the first coil LT is electrically connected between the second power device Q2 and the fourth power device Q4 through the first capacitor CT1, and the second end of the first coil LT is electrically connected between the second power device Q1 and the fourth power device Q3. The above structure can realize the function of an inverter circuit.

[0021] Similarly, it is understood that the receiving end may include a second bridge circuit and a second coil Lr electrically connected to the second bridge circuit. Please continue reading. Figure 1 In some examples, the second bridge circuit described above can be understood to include a fifth power device Q5, a sixth power device Q6, a seventh power device Q7, and an eighth power device Q8; the fifth power device Q5 and the seventh power device Q7 are connected in series to form a third branch, the sixth power device Q6 and the eighth power device Q8 are connected in series to form a fourth branch, and the third and fourth branches are connected in parallel; the first end of the second coil Lr is electrically connected between the fifth power device Q5 and the seventh power device Q7, and the second end of the second coil Lr is electrically connected between the sixth power device Q6 and the eighth power device Q8 through the second capacitor Cr; the above structure can realize the function of a rectifier circuit.

[0022] Furthermore, an energy storage module connected in parallel with the fourth branch is also provided at the receiving end. This energy storage module is used to charge and store energy during foreign object detection and to discharge so that the receiving end does not receive electrical energy from the transmitting end. Understandably, this energy storage module can use a large-capacity capacitor, such as an electrolytic capacitor; other components that can be used to store electrical energy can also be used.

[0023] It should be noted that the power devices Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, and Q10 can be any one or more of IGBTs (Insulated Gate Bipolar Transistors), MOSFETs, and transistors.

[0024] Please see Figure 2 The foreign object detection method for a wireless power transmission system provided in this embodiment includes the following steps: Step S10: Control the transmitter to send electrical energy to the receiver to charge the energy storage module of the receiver; Step S20: After charging the energy storage module to the target voltage, reduce the output voltage of the transmitter to obtain the transmission power of the transmitter; wherein, the energy storage module discharges after reducing the output voltage of the transmitter, so that the receiver does not receive the electrical energy of the transmitter; Step S30: Based on the transmission power and the preset reference power, obtain the foreign object detection result; wherein, the reference power is the excitation power of the transmitter after charging the energy storage module to the target voltage and reducing the output voltage of the transmitter when there is no foreign object.

[0025] In this embodiment, during foreign object detection via steps S10-S30, the receiver is first charged to a stable target voltage. Then, the transmitter's output voltage is reduced, and the transmitter's transmission power is recorded. Since the receiver's voltage is supplied by the energy storage module after the transmitter's output voltage is reduced, the receiver does not receive power from the transmitter. At this time, the transmitter's transmission power is unaffected by the receiver and remains a stable value. If a metallic foreign object exists between the transmitter and receiver, after the transmitter reduces its output voltage, its initial value is higher (the metallic foreign object consumes some power), resulting in a measured transmission power greater than the reference power, thus achieving metallic foreign object detection. Furthermore, since both the transmission power and the reference power are measured after the transmitter's voltage is reduced, the impact of small metallic foreign objects on power can be amplified, improving test accuracy and making it effectively applicable to high-power wireless power transmission scenarios.

[0026] Step S10: Control the transmitter to send electrical energy to the receiver to charge the energy storage module of the receiver.

[0027] In step S10, a metal foreign object detection can be performed before power is supplied to the electrical equipment. The relevant control signals during execution can come from the controller of the device containing the transmitter, the controller within the electrical equipment, or an independent control module; there are no restrictions. The power source for the transmitter can be mains power, a storage battery, a solar panel, etc., and there are no restrictions.

[0028] In some possible implementations, the transmitting end may include a detection coil and a working coil; the detection coil is used to connect to the circuit when foreign object detection is performed between the transmitting and receiving ends; the working coil is used to connect to the power supply when it is necessary to transmit power to the receiving end normally after the metal foreign object detection is completed; and the mutual inductance of the detection coil is greater than that of the working coil, ensuring that the wireless power transmission system can operate in a low-power, high-efficiency state when performing metal foreign object detection, thereby improving detection accuracy and ensuring that small metal foreign objects can be detected in high-power power transmission application scenarios.

[0029] The detection coil and the working coil can be set independently or integrated together. Please refer to [link / reference]. Figure 3 In some implementations, the first coil LT includes a first lead 11, a second lead 12, and a third lead 13. The first lead 11 is electrically connected between the second power device Q2 and the fourth power device Q4 via a first capacitor CT1; while the second lead 12 and the third lead 13 are both electrically connected between the first power device Q1 and the third power device Q3. The first lead 11 can be drawn from the end of the first coil LT located at the center of the coil, the third lead 13 can be drawn from the end of the first coil LT located at the edge of the coil, and the second lead 12 can be drawn from the middle position of the first coil LT, as shown below. Figure 4 As shown. At this point, the entire first coil LT can be connected to the circuit via the first lead 11 and the third lead 13, achieving the maximum mutual inductance of the first coil LT, which can then be used as a detection coil. The portion of the first coil LT near the middle can be connected to the circuit via the first lead 11 and the second lead 12 as a working coil, enabling high-power transmission. Of course, in some examples, the mutual inductance between the second lead 12 and the third lead 13 can be designed to be larger, thus allowing the second lead 12 and the third lead 13 to also be used as a detection coil. Furthermore, more leads can be used to segment the first coil LT to meet different detection requirements; this embodiment will not elaborate further.

[0030] In other words, in some implementations, the detection coil is wound in a disc shape, and the detection coil includes a first transmitting part (such as...). Figure 4 The portion between the first lead 11 and the second lead 12 shown) and the second transmitting part (as shown) Figure 4 The portion between the second lead 12 and the third lead 13 shown), the first transmitting part and the second transmitting part are connected in series, and the second transmitting part surrounds the outside of the first transmitting part. One end of the transmitting detection coil is provided with a first transmitting end lead (such as...). Figure 4 The third lead 13 shown), a second transmitting end lead (such as) is provided between the first transmitting part and the second transmitting part. Figure 4 The second lead 12 shown) further includes, before the detection coil at the control transmitter sends electrical energy to the receiver, disconnecting the second transmitter lead and turning on the first transmitter lead to disconnect the working coil and connect the detection coil to the circuit for operation.

[0031] Understandably, when designing the first coil LT, the mutual inductance of the detection coil after it is connected to the circuit is much greater than that of the working coil, so the detection coil generally operates at low power. Therefore, a larger diameter wire can be used to make the coil part between the first lead 11 and the second lead 12, and a smaller diameter wire can be used to make the coil part between the second lead 12 and the third lead 13, thereby reducing manufacturing costs without affecting performance.

[0032] Understandably, the second coil Lr at the receiving end can also adopt the same or similar structural design as the first coil LT at the transmitting end; when higher accuracy is required, the receiving end can also be controlled to connect an independent detection coil.

[0033] Furthermore, it can be understood that executing step S10 may include: controlling the detection coil of the transmitting end to send electrical energy to the receiving end to charge the energy storage module of the receiving end to the target voltage. This further reduces the transmission power during detection and improves detection accuracy.

[0034] For example, when a wireless power transmission system needs to transmit high power, the excitation current of the transmitting circuit is large, and it is difficult to detect small metal foreign objects. At this time, the switch S2 in the control circuit can be closed, and the first lead 11 and the third lead 13 form the main circuit for detecting foreign objects in wireless power transmission (when the switch S1 is closed, lead 1 and lead 2 form the main circuit for wireless power transmission). The number of turns NT2 and the inductance LT2 between the first lead 11 and the third lead 13 are both greater than the number of turns NT1 and the inductance LT1 between the first lead 11 and the second lead 12. According to formula (1), when the coil spacing d and the radius r are constant, the mutual inductance coefficient between the coils is... It increases with the number of turns NT and Nr of the coil.

[0035] (1) in, Mutual inductance coefficient, Permeability, , These represent the number of coil turns at the transmitting and receiving ends, respectively. , These are the radii of the transmitting and receiving coils, respectively. This refers to the spacing between the transmitting and receiving coils. Based on the transformer mutual inductance coefficient... With magnetizing inductor Relationship ,in, These are the magnetizing inductances of the transmitting and receiving coils, respectively; it can be seen that when the mutual inductance coefficient... M After the increase, the magnetizing inductance Lm The excitation current will decrease as the excitation current increases. At this point, continuing with steps S10-S30 after connecting the detection coil can further improve detection accuracy.

[0036] Step S20: After charging the energy storage module to the target voltage, reduce the output voltage of the transmitter to obtain the transmission power of the transmitter; wherein, the energy storage module discharges after reducing the output voltage of the transmitter, so that the receiver does not receive the electrical energy of the transmitter.

[0037] In step S20, the control method for charging the energy storage module to the target voltage can be referred to as follows: First, the transmitter sends electrical energy to the receiver to charge the energy storage module. Then, the voltage of the energy storage module is monitored, and when the module voltage reaches the target voltage, the transmitter power is reduced to maintain the module at the target voltage; that is, the receiver bus voltage remains constant. This charging control method ensures the energy storage module is accurately charged to the target voltage and avoids overcharging that could damage it. After charging to the target voltage, the step of reducing the transmitter output voltage is executed. The voltage change curve of the energy storage module is shown below. Figure 5 As shown; where stage A is the process of the energy storage module being charged to the target voltage, stage B is the process of the energy storage module maintaining the target voltage unchanged, stage C is the process of the energy storage module discharging to achieve foreign object detection, and stage D is the stage of normal operation of the transmitter and receiver.

[0038] Furthermore, in some implementations, if the energy storage module is a capacitor (energy storage capacitor), the voltage of the energy storage capacitor is checked during charging to see if it reaches the overvoltage protection value. When the overvoltage protection value is reached, the power at the transmitting end is reduced to bring the voltage of the energy storage capacitor to a balanced state. Understandably, the target voltage at this point is the overvoltage protection value of the energy storage capacitor. Using an energy storage capacitor to implement the energy storage module can smooth the rectification after foreign object detection, avoiding the need to add components to the circuit.

[0039] When reducing the voltage at the transmitting end, the amount of reduction can be controlled to be a preset voltage. That is, the preset voltage is reduced based on the current voltage value at the transmitting end. In some embodiments, this preset voltage is not less than 1 / 4 of the standard output voltage, which is used to maintain the voltage of the energy storage module at the target voltage when there are no foreign objects between the transmitting and receiving ends. In other embodiments, the preset voltage can be 1 / 2, 2 / 3, 3 / 4, etc., of the standard output voltage, or a range thereof. This ensures that the transmission power is lower after the voltage is reduced, ensuring that smaller foreign objects are detected. The preset voltage can be a fixed voltage value to be reduced, or a proportional value to be reduced.

[0040] Step S30: Based on the transmission power and the preset reference power, obtain the foreign object detection result; wherein, the reference power is the excitation power of the transmitter after charging the energy storage module to the target voltage and reducing the output voltage of the transmitter when there is no foreign object.

[0041] In step S30, the transmit power and a preset reference power are compared to determine the foreign object detection result. If a foreign object exists between the transmitter and receiver, the transmitter will use a higher sustaining power to maintain the target voltage of the receiver's energy storage module, as the foreign object consumes some power. The first power is obtained by reducing the sustaining power by a preset voltage. If no foreign object exists between the transmitter and receiver, the transmitter will use a lower sustaining power to maintain the target voltage of the receiver's energy storage module. The power recorded after reducing the sustaining power by a preset voltage is the second power (i.e., the reference power). Therefore, in the presence of a metallic foreign object, the first power will be greater than the second power.

[0042] Understandably, when the transmission power is greater than the reference power, the foreign object detection result can be determined to indicate that there is a foreign object at both the transmitting and receiving ends; otherwise, the foreign object detection result can be determined to indicate that there is no foreign object at both the transmitting and receiving ends.

[0043] Furthermore, in some implementations, a certain margin value can be preset to reduce detection errors and improve detection efficiency and accuracy. It is understood that a comparison power can be determined using a reference power and the margin value; this comparison power is used to compare with the transmission power detected after the transmitter voltage is reduced, and the comparison power is the sum of the reference power and the margin value. That is, the foreign object detection result is obtained based on the magnitude of the transmission power and the comparison power; whereby, if the transmission power is greater than the comparison power, the foreign object detection result is determined to be the presence of a foreign object; otherwise, the foreign object detection result is determined to be the absence of a foreign object. This avoids inaccurate detection due to small fluctuations, such as the transmitter and receiver not being able to maintain consistency during each coupling, which may result in small coupling errors; compensating for the reference power with a set margin value can eliminate detection errors as much as possible and improve detection accuracy. It is understood that when the margin value is 0, the comparison power is the same as the reference power.

[0044] For example, for ease of explanation, in this embodiment, the reference power is denoted as Pck, the actual detected transmission power is denoted as Pst, and the margin value is denoted as ΔP. ​​Then, the comparison power Pck1 = Pst + ΔP. When Pst > Pck1, it indicates that a foreign object is detected; otherwise, no foreign object is detected.

[0045] In some implementations, cyclic detection can also be used to improve detection accuracy.

[0046] The execution process of one implementation method can be referred to as follows: The process involves determining whether the transmission power is greater than the comparison power. If the transmission power is greater than the comparison power, the foreign object detection result indicates the presence of a foreign object. If the transmission power is less than the comparison power, and the foreign object detection result indicates the absence of a foreign object, this result may be due to interference from the external environment. The reliability of this foreign object detection result is low, and relying on it for subsequent power transmission operations carries significant risk. Therefore, in this example, when the transmission power is less than the comparison power, steps S10-S30 are repeated until a foreign object detection result indicating the presence of a foreign object is obtained; or the process is repeated a preset number of times or for a preset duration to obtain a foreign object detection result indicating the absence of a foreign object. The preset duration and preset number of times can be customized; for example, the preset duration can be set to 5µs, 7µs, 8µs, 10µs, etc., without limitation; the preset number of times can also be set to complete within 10µs to ensure rapid startup of the equipment when no foreign object is present, improving the user experience.

[0047] The execution process of another implementation method can be referred to as follows: The process involves determining whether the transmission power is greater than the comparison power. If the transmission power is greater than the comparison power, the foreign object detection result indicates the presence of a foreign object. If the transmission power is less than the comparison power, and the foreign object detection result indicates the absence of a foreign object, this result may be due to interference from the external environment. The reliability of this foreign object detection result is low, and relying on it for subsequent power transmission operations carries significant risk. Therefore, in this example, when the transmission power is less than the comparison power, steps S10-S30 are repeated until a foreign object detection result indicating the presence of a foreign object is obtained; or the process is repeated a preset number of times or for a preset duration to obtain a foreign object detection result indicating the absence of a foreign object. The preset duration and preset number of times are explained in the previous example and will not be repeated here.

[0048] It is understandable that after detecting metal foreign objects using the method implemented in this embodiment, if a foreign object is found to be present, a prompt message can be generated, such as generating an alarm sound or turning on a warning light; if no foreign object is found to be present, the transmitter can be controlled to supply power to the receiver normally.

[0049] In summary, the foreign object detection method for a wireless power transmission system provided by the embodiments of the present invention can suppress the transmission of electrical energy from the transmitter to the receiver by charging the energy storage module and reducing the voltage at the transmitter. This enables the detection of metallic foreign objects between the transmitter and receiver under low power conditions, improving detection accuracy. It can be effectively applied to the detection of small metallic foreign objects in high-power wireless power transmission scenarios, for example, in high-power power transmission scenarios of 100W and above.

[0050] Please see Figure 6In another embodiment, a foreign object detection device 300 for a wireless power transmission system is also provided, applied to the transmitting end of the wireless power transmission equipment; the device 300 includes: A charging module 301 is used to control the transmitter to send electrical energy to the receiver to charge the energy storage module of the receiver to a target voltage; a step-down module 302 is used to reduce the output voltage of the transmitter and obtain the transmission power of the transmitter; wherein, the energy storage module discharges after reducing the output voltage of the transmitter, so that the receiver does not receive the electrical energy from the transmitter; a detection module 303 is used to obtain the foreign object detection result based on the transmission power and a preset reference power; wherein, the reference power is the excitation power of the transmitter after reducing the output voltage of the transmitter when the energy storage module is charged to the target voltage in the absence of foreign objects.

[0051] In some optional embodiments, the transmitting end includes a detection coil and a working coil, wherein the mutual inductance corresponding to the detection coil is greater than the mutual inductance corresponding to the working coil; the charging module 301 includes a charging unit for: The detection coil at the transmitting end is controlled to send electrical energy to the receiving end to charge the energy storage module of the receiving end to the target voltage.

[0052] In some optional embodiments, the detection coil is wound in a disc shape, the detection coil includes a first transmitting part and a second transmitting part, the first transmitting part and the second transmitting part are connected in series, and the second transmitting part is wrapped around the outside of the first transmitting part. One end of the transmitting detection coil is provided with a first transmitting end lead, and a second transmitting end lead is provided between the first transmitting part and the second transmitting part; the charging module 301 is further configured to: before the detection coil controlling the transmitting end sends electrical energy to the receiving end: Disconnect the second transmitting lead and connect the first transmitting lead to disconnect the working coil and connect the detection coil to the circuit for operation.

[0053] In some alternative implementations, the step-down module 302 includes a voltage regulator unit for: The transmitter is controlled to send electrical energy to the receiver to charge the energy storage module; the voltage value of the energy storage module is monitored, and when the voltage of the energy storage module reaches the target voltage, the power of the transmitter is reduced so that the energy storage module is maintained at the target voltage.

[0054] In some alternative implementations, the step-down module 302 includes a step-down unit for: The output voltage of the transmitting end is reduced by a preset voltage, wherein the preset voltage is not less than 1 / 4 of the standard output voltage; wherein the standard output voltage is used to maintain the voltage of the energy storage module at the target voltage when there are no foreign objects between the transmitting end and the receiving end.

[0055] In some optional implementations, the detection module 303 includes: The first detection unit is used to determine the comparison power based on the reference power and the preset margin value; the second detection unit is used to obtain the foreign object detection result based on the magnitude of the transmission power and the comparison power; wherein, when the transmission power is greater than the comparison power, the foreign object detection result is determined to indicate the presence of a foreign object, otherwise the foreign object detection result is determined to indicate the absence of a foreign object.

[0056] In some optional embodiments, the second detection unit is used to perform multiple foreign object detections on the wireless power transmission system. The second detection unit includes a detection subunit for: Determine whether the transmission power is greater than the comparison power; if yes, determine that the foreign object detection result indicates the presence of a foreign object; if no, repeat the following steps: control the transmitter to send electrical energy to the receiver to charge the energy storage module of the receiver; after charging the energy storage module to the target voltage, reduce the output voltage of the transmitter to obtain the transmission power of the transmitter; wherein, the energy storage module discharges after reducing the output voltage of the transmitter, so that the receiver does not receive the electrical energy from the transmitter; obtain the foreign object detection result based on the transmission power and a preset reference power; wherein, the preset reference power is the excitation power of the transmitter after charging the energy storage module to the target voltage and reducing the output voltage of the transmitter in the absence of foreign objects, until a foreign object detection result indicating the presence of a foreign object is obtained; or repeat for a preset number of times or a preset duration to obtain a foreign object detection result indicating the absence of a foreign object.

[0057] The device embodiments described above can be used to execute the foreign object detection method of the wireless power transmission system in the above embodiments of the present invention. For details not disclosed in the device embodiments described in the present invention, please refer to the foreign object detection method embodiments of the wireless power transmission system described above.

[0058] In another embodiment of the present invention, a wireless power transmission device is also provided, comprising: a transmitter configured to wirelessly transmit electrical energy, a processor, and a memory; the memory is coupled to the processor, and the memory stores instructions that, when executed by the processor, cause the wireless power transmission device to perform the steps of any of the methods described in the foregoing method embodiments.

[0059] In another embodiment of the present invention, a home appliance is also provided, comprising: a receiver; the receiver being configured to receive electrical energy transmitted by a transmitter to charge an energy storage module to a target voltage; the energy storage module of the receiver being configured to discharge when the transmitter reduces its output voltage, so that the receiver does not receive electrical energy from the transmitter; wherein the transmitter is used to acquire transmission power and, based on the transmission power and a preset reference power, obtain a foreign object detection result; the reference power is the excitation power of the transmitter after charging the energy storage module to the target voltage and reducing the output voltage of the transmitter when there is no foreign object.

[0060] In another embodiment of the present invention, an air conditioner is also provided, comprising: a receiver configured to wirelessly receive electrical energy, a processor, and a memory; the memory is coupled to the processor, and the memory stores instructions that, when executed by the processor, cause the wireless power transmission device to perform the steps of any of the methods described in the foregoing embodiments. The air conditioner may be a portable air conditioner, a dehumidifier, etc.

[0061] It should be noted that the control and related functions of the transmitter and / or receiver when implementing the metal foreign object detection function in the wireless power transmission equipment, home appliances and air conditioners provided by the present invention can be found in the content of the foregoing method embodiments, and will not be repeated here.

[0062] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions can be stored as one or more instructions or codes on or transmitted via a computer-readable medium. Other examples and embodiments are within the scope and spirit of this invention and the appended claims. For example, due to the nature of software, the functions described above can be implemented using software executed by a processor, hardware, firmware, hardwired, or any combination thereof. Furthermore, the functional units can be integrated into a single processing unit, or each unit can exist physically separately, or two or more units can be integrated into a single unit.

[0063] In the several embodiments provided by this invention, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection can be through some interfaces; the indirect coupling or communication connection of units or modules can be electrical or other forms.

[0064] The units described as separate components may or may not be physically separate. Similarly, the components of the control device may or may not be physical units; they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0065] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0066] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for detecting foreign objects in a wireless power transmission system, characterized in that, The wireless power transmission system includes a transmitter and a receiver; the method includes: The transmitter is controlled to send electrical energy to the receiver to charge the energy storage module of the receiver. After charging the energy storage module to the target voltage, the output voltage of the transmitter is reduced to obtain the transmission power of the transmitter; wherein, the energy storage module discharges after reducing the output voltage of the transmitter, so that the receiver does not receive the electrical energy from the transmitter; Based on the transmission power and the preset reference power, the foreign object detection result is obtained; wherein, the preset reference power is the excitation power of the transmitter after the energy storage module is charged to the target voltage and the output voltage of the transmitter is reduced when there is no foreign object.

2. The method as described in claim 1, characterized in that, The transmitting end includes a detection coil and a working coil, wherein the mutual inductance of the detection coil is greater than the mutual inductance of the working coil; controlling the transmitting end to send electrical energy to the receiving end to charge the energy storage module of the receiving end to the target voltage includes: The detection coil at the transmitting end is controlled to send electrical energy to the receiving end to charge the energy storage module of the receiving end to the target voltage.

3. The method as described in claim 2, characterized in that, The detection coil is wound in a disc shape, and includes a first transmitting section and a second transmitting section. The first transmitting section and the second transmitting section are connected in series, and the second transmitting section is wrapped around the outside of the first transmitting section. A first transmitting lead is provided at one end of the detection coil, and a second transmitting lead is provided between the first transmitting section and the second transmitting section. Before the detection coil of the transmitting end transmits electrical energy to the receiving end, the method further includes: Disconnect the second transmitting lead and connect the first transmitting lead to disconnect the working coil and connect the detection coil to the circuit for operation.

4. The method as described in claim 1, characterized in that, The step of charging the energy storage module to the target voltage includes: The transmitter is controlled to send electrical energy to the receiver to charge the energy storage module; The voltage value of the energy storage module is monitored, and the power of the transmitter is reduced when the voltage of the energy storage module reaches the target voltage, so that the energy storage module is maintained at the target voltage.

5. The method as described in claim 1, characterized in that, The reduction of the output voltage of the transmitter includes: The output voltage of the transmitting end is reduced by a preset voltage, wherein the preset voltage is not less than 1 / 4 of the standard output voltage; The standard output voltage is used to maintain the voltage of the energy storage module at the target voltage when there are no foreign objects between the transmitter and the receiver.

6. The method as described in claim 1, characterized in that, The process of obtaining foreign object detection results based on the transmission power and a preset reference power includes: Based on the preset reference power and the preset margin value, the comparison power is determined, wherein the comparison power is the sum of the preset reference power and the preset margin value; Based on the magnitudes of the transmission power and the comparison power, a foreign object detection result is obtained; wherein, if the transmission power is greater than the comparison power, the foreign object detection result is determined to indicate the presence of a foreign object; otherwise, the foreign object detection result is determined to indicate the absence of a foreign object.

7. The method as described in claim 6, characterized in that, Performing multiple foreign object detections on the wireless power transmission system, and obtaining foreign object detection results based on the magnitude of the transmission power and the comparison power, includes: Determine whether the transmission power is greater than the comparison power; If so, then the foreign object detection result indicates the presence of a foreign object; If not, the steps of the method described in claim 1 are executed repeatedly: controlling the transmitter to send electrical energy to the receiver to charge the energy storage module of the receiver; after charging the energy storage module to the target voltage, reducing the output voltage of the transmitter to obtain the transmission power of the transmitter; wherein, the energy storage module discharges after reducing the output voltage of the transmitter, so that the receiver does not receive the electrical energy of the transmitter; based on the transmission power and a preset reference power, a foreign object detection result is obtained; wherein, the preset reference power is the excitation power of the transmitter after charging the energy storage module to the target voltage and reducing the output voltage of the transmitter in the absence of foreign objects, until a foreign object detection result indicating the presence of foreign objects is obtained; or the process is repeated for a preset number of times or a preset duration to obtain a foreign object detection result indicating the absence of foreign objects.

8. A foreign object detection device for a wireless power transmission system, characterized in that, The device is used as a transmitter in wireless power transmission equipment; the device includes: A charging module is used to control the transmitter to send electrical energy to the receiver to charge the energy storage module of the receiver to the target voltage; A step-down module is used to reduce the output voltage of the transmitter and obtain the transmission power of the transmitter; wherein, the energy storage module discharges after reducing the output voltage of the transmitter, so that the receiver does not receive the electrical energy of the transmitter. The detection module is used to obtain foreign object detection results based on the transmission power and a preset reference power; wherein, the preset reference power is the excitation power of the transmitter after the energy storage module is charged to the target voltage and the output voltage of the transmitter is reduced when there is no foreign object.

9. The apparatus as claimed in claim 8, characterized in that, The transmitting end includes a detection coil and a working coil, wherein the mutual inductance of the detection coil is greater than the mutual inductance of the working coil; the charging module includes a charging unit for: The detection coil at the transmitting end is controlled to send electrical energy to the receiving end to charge the energy storage module of the receiving end to the target voltage.

10. A wireless power transmission device, characterized in that, include: The transmitter, processor, and memory are configured to wirelessly transmit electrical energy. The memory is coupled to the processor and stores instructions that, when executed by the processor, cause the wireless power transmission device to perform the steps of the method according to any one of claims 1-7.

11. A household appliance, characterized in that, include: Receiver; The receiving end is configured to receive electrical energy transmitted by the transmitting end to charge the energy storage module to the target voltage; The energy storage module of the receiving end is configured to discharge when the transmitting end reduces its output voltage after the energy storage module is charged to the target voltage, so that the receiving end does not receive the electrical energy of the transmitting end; wherein, the transmitting end is used to acquire the transmission power and obtain the foreign object detection result based on the transmission power and a preset reference power; the reference power is the excitation power of the transmitting end after the output voltage of the transmitting end is reduced when the energy storage module is charged to the target voltage in the absence of foreign objects.

12. An air conditioner, characterized in that, include: The receiver, processor, and memory are configured to wirelessly receive electrical energy. The memory is coupled to the processor, and the memory stores instructions that, when executed by the processor, cause the processor to perform the steps of the method according to any one of claims 1-7.

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