Electric Vehicle MC-WPT System Integrated with Self-Powered Foreign Object Detection and Its Foreign Object Detection Method

Abstract

The present invention relates to the technical field of wireless charging for electric vehicles, and specifically discloses an electric vehicle MC-WPT system integrated with self-powered foreign object detection and its control method. By designing a self-powered foreign object detection circuit including a self-powered foreign object detection coil array, a self-powered circuit, and a foreign object detection circuit, as well as a self-powered foreign object detection controller, after the self-powered foreign object detection controller enables the foreign object detection mode, it controls more than 1 self-powered foreign object detection sub-coil to be in the self-powered mode, and more than 1 self-powered foreign object detection sub-coil to be in the foreign object detection mode. The self-powered foreign object detection sub-coil in the self-powered mode can supply power to the self-powered foreign object detection controller to further generate an excitation signal source required for foreign object detection and act on the foreign object detection circuit in the foreign object detection mode, realizing self-powered foreign object detection.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless charging for electric vehicles, and in particular, to an MC-WPT system for electric vehicles integrating self-powered foreign object detection and a method for detecting foreign objects in an MC-WPT system for electric vehicles integrating self-powered foreign object detection. Background Art

[0002] Wireless power transfer (WPT) is a technology that comprehensively applies relevant theories and technologies such as power electronics and automatic control to achieve the transmission of electrical energy between the power grid (or battery) and electrical equipment through a certain carrier (such as electric field, magnetic field, microwave, laser) in a loosely coupled non-electrical contact mode. Compared with the traditional electrical contact power access technology, the wireless power transfer technology has the advantages of higher reliability and safety, smaller occupied space, flexible use mode, less susceptible to external environmental factors, strong interaction ability with the power grid, and can be applied in some extreme environments and special conditions. Therefore, it has a wider development and application in the fields of consumer electronics, medical security, electric vehicles, etc.

[0003] Magnetically-Coupled Resonant Wireless Power Transfer (MC-WPT) generates a high-frequency alternating magnetic field through the high-frequency alternating current in the transmitting coil as the carrier for power transmission. However, when metal foreign objects (such as coins, keys, paper clips) appear in or around the transmitting coil of the MC-WPT system, they will change the distribution of the high-frequency alternating magnetic field of the MC-WPT system, resulting in a decrease in the system transmission efficiency. In addition, metal foreign objects have potential safety hazards due to heat generation caused by eddy current effects and hysteresis losses. Therefore, in order to ensure the safe operation and system efficiency of the MC-WPT system, the detection technology for metal foreign objects is indispensable.

[0004] Existing foreign object coil detection schemes all use a switching power supply to supply power to the foreign object detection signal board. The foreign object detection coil array is integrated with the power transmitting coil. If its detection circuit is placed in the power control box, there will be leads several meters long. Since foreign object detection itself is to detect the change of weak signals, it is very easy to introduce interference and affect the accuracy of foreign object detection. Summary of the Invention

[0005] The present invention provides an MC-WPT system for electric vehicles integrating self-powered foreign object detection and its control method, and the technical problem to be solved is: how to achieve self-power supply of the foreign object detection circuit.

[0006] To solve the above technical problems, the present invention provides an electric vehicle MC-WPT system integrated with self-powered foreign object detection, which is provided with a ground end; the ground end includes a power transmitting circuit, a self-powered foreign object detection circuit, and a self-powered foreign object detection controller connected to the self-powered foreign object detection circuit;

[0007] The power transmitting circuit is provided with a primary transmitting coil, and the self-powered foreign object detection circuit is provided with a self-powered foreign object detection coil array; the primary transmitting coil and the self-powered foreign object detection coil array are hierarchically arranged;

[0008] The self-powered foreign object detection coil array includes a plurality of self-powered foreign object detection sub-coils arranged in an array; the self-powered foreign object detection circuit further includes a plurality of self-powered foreign object detection sub-circuits connected to the plurality of self-powered foreign object detection sub-coils one by one, and each self-powered foreign object detection sub-circuit includes a self-powered circuit and a foreign object detection circuit connected in parallel with the corresponding self-powered foreign object detection sub-coil; the self-powered foreign object detection controller is connected to each self-powered circuit and foreign object detection circuit;

[0009] The self-powered foreign object detection controller is used to control more than 1 self-powered foreign object detection sub-coils to be in the self-powered mode and more than 1 self-powered foreign object detection sub-coils to be in the foreign object detection mode at the same time, and switch the mode at the next moment to ensure that all the self-powered foreign object detection sub-coils are in the foreign object detection mode at least once during the foreign object detection period; the self-powered foreign object detection sub-coils in the self-powered mode are connected to the corresponding self-powered circuits and disconnected from the corresponding foreign object detection circuits, and the self-powered circuits supply power to the self-powered foreign object detection controller; the self-powered foreign object detection sub-coils in the foreign object detection mode are disconnected from the corresponding self-powered circuits and connected to the corresponding foreign object detection circuits, and the self-powered foreign object detection controller generates an excitation signal source to act on the foreign object detection circuit, obtains the characteristic signal of the foreign object detection circuit under the excitation signal source, and then determines whether there is a metal foreign object according to the characteristic signal and determines the position of the metal foreign object when there is a metal foreign object.

[0010] Preferably, the self-powered foreign object detection coil array includes MN self-powered foreign object detection sub-coils arranged in an M×N array, M≥2, N≥2; the ground end further includes a ground end controller connected to the self-powered foreign object detection controller; the ground end controller is used to control the self-powered foreign object detection controller to start self-powered foreign object detection;

[0011] The control process of the self-powered foreign object detection controller for the self-powered foreign object detection coil array after starting self-powered foreign object detection includes the steps:

[0012] A1. Control the self-powered foreign object detection sub-coils in the odd columns of odd rows to be in the self-powered mode, and the self-powered foreign object detection sub-coils in the even columns of even rows to be in the foreign object detection mode. The self-powered foreign object detection controller obtains the characteristic signals of the foreign object detection circuit in each foreign object detection mode;

[0013] A2. Control the self-powered foreign object detection sub-coils in the even columns of even rows to be in the self-powered mode, and control the self-powered foreign object detection sub-coils in the odd columns of odd rows to be in the foreign object detection mode. The self-powered foreign object detection controller obtains the characteristic signals of the foreign object detection circuit in each foreign object detection mode.

[0014] Preferably, the control process of the self-powered foreign object detection coil array by the self-powered foreign object detection controller after enabling the self-powered foreign object detection includes the steps:

[0015] B1. Control the self-powered foreign object detection sub-coil in the first row and first column to be in the foreign object detection mode, while other self-powered foreign object detection sub-coils are in the self-powered mode. The self-powered foreign object detection controller obtains the characteristic signals of the corresponding foreign object detection circuit;

[0016] B2. Similar to step B1, in the order of rows from top to bottom and columns from left to right, each time make one self-powered foreign object detection sub-coil be in the foreign object detection mode, while other self-powered foreign object detection sub-coils are in the self-powered mode. The self-powered foreign object detection controller obtains the characteristic signals of the corresponding foreign object detection circuit.

[0017] Preferably, the self-powered circuit includes a self-powered tuning circuit and a self-powered rectifier filter circuit connected in sequence;

[0018] The self-powered tuning circuit uses a first compensation capacitor connected in series with the self-powered foreign object detection sub-coil, and the first compensation capacitor is tuned to the resonance frequency f1 of the power emission circuit;

[0019] The self-powered rectifier filter circuit is connected to the self-powered foreign object detection controller to supply power to it.

[0020] Preferably, the foreign object detection circuit includes a detection tuning circuit, a filter amplification circuit, and an amplitude-phase detection circuit;

[0021] The detection tuning circuit uses a second compensation capacitor connected in series with the self-powered foreign object detection sub-coil; the filter amplification circuit is connected between the excitation signal source and the detection tuning circuit, and is used to amplify and filter the AC signal generated by the detection tuning circuit;

[0022] The amplitude-phase detection circuit uses a series resistor, and the self-powered foreign object detection controller detects the amplitude and phase of the voltage and current of the series resistor;

[0023] The excitation frequency of the excitation signal source is f2, and the second compensation capacitor is tuned to the frequency f2, where f2 > f1. The magnitudes of f1 and f2 are set such that the adjacent foreign object detection circuit and the self-powered circuit do not affect each other.

[0024] Preferably, the self-powered foreign object detection controller analyzes the coil equivalent impedance of the self-powered foreign object detection sub-coil according to the magnitudes and phases of the voltage and current of the series resistor. If the coil equivalent impedance matches the preset coil equivalent impedance when there is a metal foreign object, it is determined that there is a metal foreign object on the self-powered foreign object detection sub-coil; otherwise, there is no metal foreign object.

[0025] Preferably, the electric energy transmitting circuit includes a power frequency power grid, a primary rectification circuit, a primary resonance compensation network, and the primary transmitting coil connected in sequence; the size of the self-powered foreign object detection coil array covers the primary transmitting coil;

[0026] The electric vehicle MC-WPT system further includes a vehicle-mounted terminal; the vehicle-mounted terminal includes a secondary receiving coil, a secondary resonance compensation network, a rectification and filtering circuit, and a load connected in sequence;

[0027] The self-powered foreign object detection controller is also connected to an energy storage power supply. When the self-powered circuit operates, the energy storage power supply stores electric energy; in the next start of the self-powered foreign object detection, if the electric energy of the energy storage power supply exceeds the first preset electric energy, the self-powered foreign object detection controller controls all self-powered foreign object detection sub-coils to be in the foreign object detection mode.

[0028] The present invention also provides a foreign object detection method for an electric vehicle MC-WPT system integrated with self-powered foreign object detection, which is characterized in that it includes the steps of:

[0029] S1. Start the self-powered foreign object detection, control more than 1 self-powered foreign object detection sub-coils to be in the self-powered mode, and more than 1 self-powered foreign object detection sub-coils to be in the foreign object detection mode;

[0030] S2. Obtain the characteristic signal of the foreign object detection circuit under the excitation signal source, and then determine whether there is a metal foreign object according to the characteristic signal and determine the position of the metal foreign object when there is a metal foreign object.

[0031] Further, the step S1 specifically includes the steps of:

[0032] A1. Control the self-powered foreign object detection sub-coils in the odd columns of the odd rows to be in the self-powered mode, and the self-powered foreign object detection sub-coils in the even columns of the even rows to be in the foreign object detection mode. The self-powered foreign object detection controller obtains the characteristic signal of the foreign object detection circuit in each foreign object detection mode;

[0033] A2. Control the self-powered foreign object detection sub-coils in the even rows and even columns to be in the self-powered mode, and control the self-powered foreign object detection sub-coils in the odd rows and odd columns to be in the foreign object detection mode. The self-powered foreign object detection controller obtains the characteristic signals of the foreign object detection circuit in each foreign object detection mode.

[0034] Further, step S1 specifically includes the steps of:

[0035] B1. Control the self-powered foreign object detection sub-coil in the first row and first column to be in the foreign object detection mode, while other self-powered foreign object detection sub-coils are in the self-powered mode. The self-powered foreign object detection controller obtains the characteristic signals of the corresponding foreign object detection circuit;

[0036] B2. In the same way as step B1, in the order of rows from top to bottom and columns from left to right, each time make one self-powered foreign object detection sub-coil be in the foreign object detection mode, while other self-powered foreign object detection sub-coils are in the self-powered mode. The self-powered foreign object detection controller obtains the characteristic signals of the corresponding foreign object detection circuit.

[0037] The integrated self-powered foreign object detection electric vehicle MC-WPT system and its control method provided by the present invention, by designing a self-powered foreign object detection circuit including a self-powered foreign object detection coil array, a self-powered circuit and a foreign object detection circuit, and a self-powered foreign object detection controller. After the foreign object detection mode is turned on, the self-powered foreign object detection controller controls more than 1 self-powered foreign object detection sub-coils to be in the self-powered mode, and more than 1 self-powered foreign object detection sub-coils to be in the foreign object detection mode. And the self-powered foreign object detection sub-coils in the self-powered mode can supply power to the self-powered foreign object detection controller to further generate an excitation signal source required for foreign object detection and act on the foreign object detection circuit in the foreign object detection mode, realizing self-powered foreign object detection. The self-powered circuit and the foreign object detection circuit can be regarded as frequency division multiplexing of the self-powered foreign object detection sub-coils, so that the foreign object detection system can efficiently pick up the power from the ground transmitting coil in the power supply mode; in the foreign object detection mode, high-sensitivity detection of foreign objects can be realized. Description of the Drawings

[0038] Figure 1 is the architecture diagram of the integrated self-powered foreign object detection electric vehicle MC-WPT system provided by the embodiment of the present invention;

[0039] Figure 2 is the hierarchical schematic diagram of the magnetic coupling mechanism provided by the embodiment of the present invention;

[0040] Figure 3 is the top view of the magnetic coupling mechanism provided by the embodiment of the present invention;

[0041] Figure 4It is a partial circuit diagram of the electric vehicle MC-WPT system with integrated self-powered foreign object detection provided by an embodiment of the present invention. Specific Embodiments

[0042] The embodiments of the present invention will be specifically described below in conjunction with the accompanying drawings. The given embodiments are only for illustrative purposes and should not be construed as a limitation of the present invention. The accompanying drawings are only for reference and illustration and do not constitute a limitation on the protection scope of the present invention. Because many changes can be made to the present invention without departing from its spirit and scope.

[0043] An embodiment of the present invention provides an electric vehicle MC-WPT system with integrated self-powered foreign object detection, as Figure 1 shown in the overall block diagram of the system, which includes a ground end and a vehicle-mounted end. Among them, the ground end includes a power transmission circuit, a self-powered foreign object detection circuit, and a self-powered foreign object detection controller connected to the self-powered foreign object detection circuit, and also includes a ground end controller connected to the self-powered foreign object detection controller and the power transmission circuit (the high-frequency inverter in it).

[0044] The power transmission circuit includes a power frequency power grid, a primary rectification circuit, a primary resonance compensation network, and a primary transmission coil connected in sequence. The self-powered foreign object detection circuit includes a self-powered foreign object detection coil array. The self-powered foreign object detection coil array includes a plurality of self-powered foreign object detection sub-coils arranged in an array. The self-powered foreign object detection circuit also includes a plurality of self-powered foreign object detection sub-circuits connected to the plurality of self-powered foreign object detection sub-coils one by one. The self-powered foreign object detection sub-circuit includes a self-powered circuit and a foreign object detection circuit connected in parallel with its corresponding self-powered foreign object detection sub-coil; the self-powered foreign object detection controller is connected to each self-powered circuit and foreign object detection circuit. The self-powered foreign object detection coil array includes MN self-powered foreign object detection sub-coils arranged in an M×N array, where M≥2 and N≥2.

[0045] The vehicle-mounted end includes a secondary receiving coil, a secondary resonance compensation network, a rectification and filtering circuit, and a load connected in sequence.

[0046] The ground end controller is used to control the self-powered foreign object detection controller to turn on the self-powered foreign object detection.

[0047] As Figure 2As shown in the hierarchical schematic diagram, the primary side transmitting coil, the self-powered foreign object detection coil array, and the secondary side receiving coil are hierarchically arranged. As a complete coupling mechanism, magnetic cores and shielding aluminum plates are provided both under the primary side transmitting coil and above the secondary side transmitting coil. Among them, the sizes of the primary side transmitting coil and the secondary side transmitting coil are designed in accordance with "GBT 38775.6-2021 Electric Vehicle Wireless Charging System Part 6: Interoperability Requirements and Testing for the Ground End" and "GBT 38775.7-2021 Electric Vehicle Wireless Charging System Part 7: Interoperability Requirements and Testing for the Vehicle End" respectively, and the size of the self-powered foreign object detection coil array covers the primary side transmitting coil. Figure 2 The top view of the magnetic coupling mechanism shown in Figure 3 As shown, the size relationship between the coils can be clearly seen. In this example, Figure 3 Taking the 4*4 array detection coil shown as an example, each detection coil has two working modes: the power supply mode and the foreign object detection mode.

[0048] When foreign object detection is enabled, the self-powered foreign object detection controller is used to control more than 1 self-powered foreign object detection sub-coil to be in the self-powered mode and more than 1 self-powered foreign object detection sub-coil to be in the foreign object detection mode at the same time, and switch the mode at the next moment to ensure that all self-powered foreign object detection sub-coils are in the foreign object detection mode at least once during the foreign object detection period; the self-powered foreign object detection sub-coil in the self-powered mode is connected to its corresponding self-powered circuit and disconnected from its corresponding foreign object detection circuit, and the self-powered circuit powers the self-powered foreign object detection controller; the self-powered foreign object detection sub-coil in the foreign object detection mode is disconnected from its corresponding self-powered circuit and connected to its corresponding foreign object detection circuit, and the self-powered foreign object detection controller generates an excitation signal source to act on the foreign object detection circuit, and obtains the characteristic signal of the foreign object detection circuit under this excitation signal source, and then determines whether there is a metal foreign object according to the characteristic signal and determines the position of the metal foreign object when there is a metal foreign object.

[0049] In addition, the self-powered foreign object detection controller in this embodiment is also connected to an energy storage power supply, and when the self-powered circuit works, the energy storage power supply stores electrical energy.

[0050] In this embodiment, as the first control method, the control process of the self-powered foreign object detection controller for the self-powered foreign object detection coil array after enabling the self-powered foreign object detection includes the steps of:

[0051] A1. Control the self-powered foreign object detection sub-coils in the odd columns of the odd rows to be in the self-powered mode, and the self-powered foreign object detection sub-coils in the even columns of the even rows to be in the foreign object detection mode, and the self-powered foreign object detection controller obtains the characteristic signals of the foreign object detection circuits in each foreign object detection mode;

[0052] A2. Control the self-powered foreign object detection sub-coils in the even rows and even columns to be in the self-powered mode, and control the self-powered foreign object detection sub-coils in the odd rows and odd columns to be in the foreign object detection mode. The self-powered foreign object detection controller obtains the characteristic signals of the foreign object detection circuits in each foreign object detection mode.

[0053] This control method only requires one mode switch to enable all self-powered foreign object detection sub-coils to be in the foreign object detection mode once, and can complete a full-range and rapid detection of foreign objects.

[0054] Of course, as two other control methods, the control process of the self-powered foreign object detection controller for the self-powered foreign object detection coil array after enabling the self-powered foreign object detection includes the steps:

[0055] B1. Control the self-powered foreign object detection sub-coil in the first row and the first column to be in the foreign object detection mode, while other self-powered foreign object detection sub-coils are in the self-powered mode. The self-powered foreign object detection controller obtains the characteristic signals of the corresponding foreign object detection circuits.

[0056] B2. Similar to step B1, in the order from top to bottom by row and from left to right by column, each time one self-powered foreign object detection sub-coil is in the foreign object detection mode, while other self-powered foreign object detection sub-coils are in the self-powered mode. The self-powered foreign object detection controller obtains the characteristic signals of the corresponding foreign object detection circuits.

[0057] This method only controls one self-powered foreign object detection sub-coil to be in the detection mode each time, while other coils are in the self-powered mode, and is suitable for the situation where the energy of the energy storage power supply connected to the self-powered foreign object detection controller is less and needs to be charged. Once this control method is enabled, before the energy storage power supply is fully charged, in each subsequent foreign object detection by the self-powered foreign object detection controller, this method is used to control the self-powered foreign object detection coil array.

[0058] After that, in the foreign object detection after being fully charged, the self-powered foreign object detection controller controls all self-powered foreign object detection sub-coils to be in the foreign object detection mode (the third control method) until the energy of the energy storage power supply drops below the first preset energy, and then starts to use the first control method (i.e., steps A1 and A2) to control the self-powered foreign object detection coil array. When the energy of the energy storage power supply drops below the second preset energy, the second control method (i.e., steps B1 and B2) is used for control.

[0059] Briefly speaking, if the self-powered foreign object detection controller is not connected to a energy storage power supply, the first control method is preferentially adopted. If the self-powered foreign object detection controller is connected to a energy storage power supply, when the foreign object detection is enabled, if the previous control method was the second control method and the energy storage power supply is not fully charged, the second control method is still adopted. If the previous control method was not the second control method, if the energy storage power supply is above the first preset power at this time, the third control method is adopted. When the energy storage power supply is between the first preset power and the second preset power, the first control method is adopted. When the energy storage power supply is below the second preset power, the second control method is adopted.

[0060] The foreign object detection times of the three control methods are: the third control method < the first control method < the second control method.

[0061] By flexibly selecting the three control methods, the foreign object detection time can be shortened as much as possible, reducing the impact on the charging of the electric vehicle.

[0062] Specifically, as Figure 4 shown in the circuit diagram, the self-powered circuit includes a self-powered tuning circuit and a self-powered rectifier and filter circuit connected in sequence;

[0063] The self-powered tuning circuit uses a first compensation capacitor (C fod1 ) connected in series with the self-powered foreign object detection sub-coil (L s1 ), and the first compensation capacitor is tuned to the resonance frequency f1 of the power emission circuit;

[0064] The self-powered rectifier and filter circuit is connected to the self-powered foreign object detection controller to supply power to it.

[0065] The foreign object detection circuit includes a detection tuning circuit, a filter and amplifier circuit, and an amplitude and phase detection circuit;

[0066] The detection tuning circuit uses a second compensation capacitor (C fod1 ) connected in series with the self-powered foreign object detection sub-coil; the filter and amplifier circuit (including a filter capacitor C hf and an amplifier) is connected between the excitation signal source and the detection tuning circuit, and is used to amplify and filter the AC signal generated by the detection tuning circuit;

[0067] The amplitude and phase detection circuit uses a series resistor (R fod1 ), and the self-powered foreign object detection controller detects the amplitude and phase of the voltage and current of the series resistor;

[0068] The excitation frequency of the excitation signal source is f2, the second compensation capacitor is tuned to the frequency f2, f2 > f1, and the magnitudes of f1 and f2 are set so that the adjacent foreign object detection circuit and the self-powered circuit do not affect each other.

[0069] To achieve stable and continuous power supply for the foreign object detection signal board, the LCC-S circuit topology is adopted in this embodiment to realize the constant voltage output of the self-power supply loop. The circuit topology is as follows Figure 4 shown.

[0070] The self-powered foreign object detection controller analyzes the coil equivalent impedance of the self-powered foreign object detection sub-coil based on the amplitude and phase of the voltage and current of the series resistor (because the presence of metal foreign objects will change the coil impedance, which is used as the basis for detection). If the coil equivalent impedance matches the preset coil equivalent impedance when there is a metal foreign object, it is determined that there is a metal foreign object on the self-powered foreign object detection sub-coil; otherwise, there is no metal foreign object.

[0071] The embodiment of the present invention also provides a foreign object detection method for an electric vehicle MC-WPT system integrated with self-powered foreign object detection, including the steps:

[0072] S1. Turn on the self-powered foreign object detection, control more than 1 self-powered foreign object detection sub-coils to be in the self-power supply mode, and more than 1 self-powered foreign object detection sub-coils to be in the foreign object detection mode;

[0073] S2. Obtain the characteristic signal of the foreign object detection circuit under the excitation signal source, and then determine whether there is a metal foreign object according to the characteristic signal and determine the position of the metal foreign object when there is a metal foreign object.

[0074] Corresponding to the first control method above, step S1 specifically includes the steps:

[0075] A1. Control the self-powered foreign object detection sub-coils in the odd columns of the odd rows to be in the self-power supply mode, and the self-powered foreign object detection sub-coils in the even columns of the even rows to be in the foreign object detection mode. The self-powered foreign object detection controller obtains the characteristic signal of the foreign object detection circuit in each foreign object detection mode;

[0076] A2. Control the self-powered foreign object detection sub-coils in the even columns of the even rows to be in the self-power supply mode, and control the self-powered foreign object detection sub-coils in the odd columns of the odd rows to be in the foreign object detection mode. The self-powered foreign object detection controller obtains the characteristic signal of the foreign object detection circuit in each foreign object detection mode.

[0077] Corresponding to the second control method above, step S1 specifically includes the steps:

[0078] B1. Control the self-powered foreign object detection sub-coil in the first row and the first column to be in the foreign object detection mode, while other self-powered foreign object detection sub-coils are in the self-power supply mode. The self-powered foreign object detection controller obtains the characteristic signal of the corresponding foreign object detection circuit;

[0079] B2. Similarly to step B1, in the order from top to bottom by row and from left to right by column, each self-powered foreign object detection sub-coil is put into the foreign object detection mode one by one, while other self-powered foreign object detection sub-coils are in the self-powered mode. The self-powered foreign object detection controller acquires the characteristic signals of the corresponding foreign object detection circuit.

[0080] Of course, the control of the self-powered foreign object detection controller over the self-powered foreign object detection coil array described above is also applicable to this method, and the redundant content will not be elaborated here.

[0081] In summary, for the electric vehicle MC-WPT system with integrated self-powered foreign object detection and its control method provided by the embodiments of the present invention, by designing a self-powered foreign object detection circuit including a self-powered foreign object detection coil array, a self-powered circuit, and a foreign object detection circuit, and a self-powered foreign object detection controller, after the foreign object detection mode is turned on, the self-powered foreign object detection controller controls more than 1 self-powered foreign object detection sub-coils to be in the self-powered mode, and more than 1 self-powered foreign object detection sub-coils to be in the foreign object detection mode. The self-powered foreign object detection sub-coils in the self-powered mode can supply power to the self-powered foreign object detection controller to further generate an excitation signal source required for foreign object detection and act on the foreign object detection circuit in the foreign object detection mode, realizing self-powered foreign object detection. The self-powered circuit and the foreign object detection circuit can be regarded as frequency division multiplexing of the self-powered foreign object detection sub-coils, enabling the foreign object detection system to efficiently pick up the power from the ground transmitting coil in the power supply mode; and realizing high-sensitivity detection of foreign objects in the foreign object detection mode.

[0082] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. An electric vehicle MC-WPT system integrated with self-powered foreign object detection, characterized in that There is a ground end; the ground end includes a power transmission circuit, a self-powered foreign object detection circuit, and a self-powered foreign object detection controller connected to the self-powered foreign object detection circuit; The power transmission circuit is provided with a primary side transmitting coil, and the self-powered foreign object detection circuit is provided with a self-powered foreign object detection coil array; the primary side transmitting coil and the self-powered foreign object detection coil array are hierarchically arranged; The self-powered foreign object detection coil array includes a plurality of self-powered foreign object detection sub-coils arranged in an array; the self-powered foreign object detection circuit further includes a plurality of self-powered foreign object detection sub-circuits connected to the plurality of self-powered foreign object detection sub-coils one by one. The self-powered foreign object detection sub-circuit includes a self-powered circuit and a foreign object detection circuit connected in parallel with its corresponding self-powered foreign object detection sub-coil; the self-powered foreign object detection controller is connected to each self-powered circuit and foreign object detection circuit; The self-powered foreign object detection controller is used to control more than 1 self-powered foreign object detection sub-coil to be in the self-powered mode and more than 1 self-powered foreign object detection sub-coil to be in the foreign object detection mode at the same time, and switch the mode at the next moment to ensure that all self-powered foreign object detection sub-coils are in the foreign object detection mode at least once during the foreign object detection period; the self-powered foreign object detection sub-coil in the self-powered mode is connected to its corresponding self-powered circuit and disconnected from its corresponding foreign object detection circuit, and the self-powered circuit supplies power to the self-powered foreign object detection controller; the self-powered foreign object detection sub-coil in the foreign object detection mode is disconnected from its corresponding self-powered circuit and connected to its corresponding foreign object detection circuit, and the self-powered foreign object detection controller generates an excitation signal source to act on the foreign object detection circuit, and obtains the characteristic signal of the foreign object detection circuit under the excitation signal source, and then determines whether there is a metal foreign object according to the characteristic signal and determines the position of the metal foreign object when there is a metal foreign object.

2. The integrated self-powered foreign object detection electric vehicle MC-WPT system according to claim 1, characterized in that, The self-powered foreign object detection coil array includes MN self-powered foreign object detection sub-coils arranged in an M×N array, M≥2, N≥2; the ground end further includes a ground end controller connected to the self-powered foreign object detection controller; the ground end controller is used to control the self-powered foreign object detection controller to start self-powered foreign object detection; The control process of the self-powered foreign object detection controller for the self-powered foreign object detection coil array after starting self-powered foreign object detection includes the steps: A1. Control the self-powered foreign object detection sub-coils in the odd columns of the odd rows to be in the self-powered mode, and the self-powered foreign object detection sub-coils in the even columns of the even rows to be in the foreign object detection mode. The self-powered foreign object detection controller obtains the characteristic signal of the foreign object detection circuit in each foreign object detection mode; A2. Control the self-powered foreign object detection sub-coils in the even columns of the even rows to be in the self-powered mode, and control the self-powered foreign object detection sub-coils in the odd columns of the odd rows to be in the foreign object detection mode. The self-powered foreign object detection controller obtains the characteristic signal of the foreign object detection circuit in each foreign object detection mode.

3. The integrated self-powered foreign object detection electric vehicle MC-WPT system according to claim 2, characterized in that, The control process of the self-powered foreign object detection controller for the self-powered foreign object detection coil array after starting self-powered foreign object detection includes the steps: B1. Control the self-powered foreign object detection sub-coil in the first row and first column to be in the foreign object detection mode, while other self-powered foreign object detection sub-coils are in the self-powered mode. The self-powered foreign object detection controller obtains the characteristic signals of the corresponding foreign object detection circuits. B2. Similarly to step B1, in the order from top to bottom by row and from left to right by column, each time make one self-powered foreign object detection sub-coil be in the foreign object detection mode, while other self-powered foreign object detection sub-coils are in the self-powered mode. The self-powered foreign object detection controller obtains the characteristic signals of the corresponding foreign object detection circuits.

4. The integrated self-powered foreign object detection electric vehicle MC-WPT system according to claim 2, characterized in that: The self-powered circuit includes a self-powered tuning circuit and a self-powered rectifying and filtering circuit connected in sequence. The self-powered tuning circuit adopts a first compensation capacitor connected in series with the self-powered foreign object detection sub-coil, and the first compensation capacitor is tuned to the resonant frequency of the power emission circuit f 1; The self-powered rectifying and filtering circuit is connected to the self-powered foreign object detection controller to supply power to it.

5. The integrated self-powered foreign object detection electric vehicle MC-WPT system according to claim 4, characterized in that: The foreign object detection circuit includes a detection tuning circuit, a filtering and amplifying circuit, and an amplitude-phase detection circuit. The detection tuning circuit uses a second compensation capacitor connected in series with the self-powered foreign object detection sub-coil. The filtering and amplifying circuit is connected between the excitation signal source and the detection tuning circuit and is used to amplify and filter the AC signal generated by the detection tuning circuit. The amplitude-phase detection circuit uses a series resistor, and the self-powered foreign object detection controller detects the amplitude and phase of the voltage and current of the series resistor. The excitation frequency of the excitation signal source is f 2, and the second compensation capacitor is tuned to the frequency f 2, f 2 > f 1, f 1, f The magnitudes of 1 and 2 are set such that the adjacent foreign object detection circuit and the self-powered circuit do not affect each other.

6. The integrated self-powered foreign object detection electric vehicle MC-WPT system according to claim 5, characterized in that: The self-powered foreign object detection controller analyzes the coil equivalent impedance of the self-powered foreign object detection sub-coil according to the amplitude and phase of the voltage and current of the series resistor. If the coil equivalent impedance matches the preset coil equivalent impedance when there is a metal foreign object, it is determined that there is a metal foreign object on the self-powered foreign object detection sub-coil; otherwise, there is no metal foreign object.

7. The electric vehicle MC-WPT system integrated with self-powered foreign object detection according to claim 5, characterized in that: The power transmission circuit includes a power frequency power grid, a primary rectifying circuit, a primary resonant compensation network, and the primary transmitting coil connected in sequence. The size of the self-powered foreign object detection coil array covers the primary transmitting coil. This electric vehicle MC-WPT system further includes an in-vehicle terminal. The in-vehicle terminal includes a secondary receiving coil, a secondary resonant compensation network, a rectifying and filtering circuit, and a load connected in sequence. The self-powered foreign object detection controller is also connected to an energy storage power supply. When the self-powered circuit works, the energy storage power supply stores electrical energy. In the next start of self-powered foreign object detection, if the electrical energy of the energy storage power supply exceeds the first preset electrical energy, the self-powered foreign object detection controller controls all self-powered foreign object detection sub-coils to be in the foreign object detection mode.

8. The foreign object detection method of the electric vehicle MC-WPT system integrating self-powered foreign object detection according to any one of claims 1 to 7, characterized in that, Including the steps: S1. Turn on the self-powered foreign object detection, control more than 1 self-powered foreign object detection sub-coils to be in the self-powered mode, and more than 1 self-powered foreign object detection sub-coils to be in the foreign object detection mode. S2. Obtain the characteristic signals of the foreign object detection circuit under the excitation signal source, and then determine whether there is a metal foreign object according to the characteristic signals and determine the position of the metal foreign object when there is a metal foreign object.

9. The foreign object detection method of the electric vehicle MC-WPT system integrating self-powered foreign object detection according to claim 8, characterized in that, The specific steps of step S1 include the steps: A1. Control the self-powered foreign object detection sub-coils in the odd columns of odd rows to be in the self-powered mode, and the self-powered foreign object detection sub-coils in the even columns of even rows to be in the foreign object detection mode. The self-powered foreign object detection controller obtains the characteristic signals of the foreign object detection circuit in each foreign object detection mode; A2. Control the self-powered foreign object detection sub-coils in the even columns of even rows to be in the self-powered mode, and control the self-powered foreign object detection sub-coils in the odd columns of odd rows to be in the foreign object detection mode. The self-powered foreign object detection controller obtains the characteristic signals of the foreign object detection circuit in each foreign object detection mode.

10. The integrated self-powered foreign object detection electric vehicle MC-WPT system according to claim 8, characterized in that, The specific steps of step S1 include the following steps: B1. Control the self-powered foreign object detection sub-coil in the first row and first column to be in the foreign object detection mode, while other self-powered foreign object detection sub-coils are in the self-powered mode. The self-powered foreign object detection controller obtains the characteristic signals of the corresponding foreign object detection circuit; B2. Similarly to step B1, in the order from top to bottom by row and from left to right by column, each time make one self-powered foreign object detection sub-coil be in the foreign object detection mode, while other self-powered foreign object detection sub-coils are in the self-powered mode. The self-powered foreign object detection controller obtains the characteristic signals of the corresponding foreign object detection circuit.

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