Wireless Charging Startup Control Method, System and Storage Medium

Abstract

The present invention discloses a method, a system and a storage medium for controlling the start of wireless charging, relating to the technical field of wireless charging. The method includes: when it is detected that an electromagnetic induction connection is established between the secondary device and the primary device, obtaining the primary coil current of the primary device and the secondary coil current of the secondary device, and obtaining the secondary impedance angle; determining whether the primary coil current is greater than a first preset value and whether the secondary impedance angle is less than a preset secondary impedance angle; controlling the impedance mode of the secondary device to be a capacitive impedance mode, or controlling the impedance mode of the secondary device to be an inductive impedance mode or a resistive impedance mode; based on the impedance mode of the secondary device, controlling the primary device and the secondary device to perform energy transfer. The present invention solves the problem that the existing wireless charging system affects the power transmission efficiency, and achieves the effect of improving the power transmission ability of the wireless charging system when applied under different working conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless charging, and particularly to a wireless charging start control method, system, and storage medium. Background Art

[0002] When the wireless charging technology is applied in the field of electric vehicles, the working conditions are relatively complex. Due to the differences in parameters such as the ground clearance, output voltage range, and charging power of different vehicle models, as well as the uncertainty of the load of the wireless charging system and the randomness of electric vehicle parking, etc., high specifications are put forward for the circuit design and control strategy of the current wireless charging system. Based on this requirement, controllable circuits are set on the equipment on both the infrastructure side and the vehicle-mounted side of the existing wireless charging system to meet the charging function and charging performance requirements under different working conditions. However, in the existing wireless charging system, there are still some problems when controlling the controllable circuit. For example, in the charging start stage, the controllable circuit is not controlled in combination with the actual state of the wireless charging system, resulting in the inability to achieve full power output subsequently and / or affecting the power transmission efficiency. Summary of the Invention

[0003] The main purpose of the present invention is to provide a wireless charging start control method, system, and storage medium, aiming to solve the technical problem that in the existing wireless charging system, the controllable circuit is not controlled in combination with the actual state of the wireless charging system in the charging start stage, affecting the power transmission efficiency.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] In a first aspect, the present invention provides a wireless charging start control method, which is applied to a wireless charging system. The system includes a primary device and a secondary device. The method includes:

[0006] When it is detected that an electromagnetic induction connection is established between the secondary device and the primary device, obtain the primary coil current of the primary device and the secondary coil current of the secondary device;

[0007] According to the primary coil current and the secondary coil current, obtain the secondary impedance angle;

[0008] Judge whether the primary coil current is greater than a first preset value, and whether the secondary impedance angle is less than a preset secondary impedance angle;

[0009] If the primary coil current is greater than the first preset value and the secondary impedance angle is less than the preset secondary impedance angle, then control the impedance mode of the secondary device to be a capacitive impedance mode;

[0010] If the primary side coil current is greater than a first preset value and the secondary side impedance angle is greater than or equal to a preset secondary side impedance angle, control the impedance mode of the secondary side device to be an inductive impedance mode or a resistive impedance mode;

[0011] Based on the impedance mode of the secondary side device, control the primary side device and the secondary side device to perform energy transfer.

[0012] Optionally, in the above wireless charging start control method, the primary side device includes an inverter circuit and a primary side circuit connected to each other, and the secondary side device includes a secondary side circuit and a controllable rectifier circuit connected to each other;

[0013] The primary side circuit includes an inductor L1, a capacitor Cp and a capacitor C1, and a primary side coil Lp. One end of the inductor L1 is connected to the inverter circuit, and the other end of the inductor L1 is respectively connected to one end of the capacitor Cp and one end of the capacitor C1. The other end of the capacitor Cp is connected to one end of the primary side coil Lp. The other end of the primary side coil Lp and the other end of the capacitor C1 are respectively connected to the inverter circuit;

[0014] The secondary side circuit includes a secondary side coil Ls, a capacitor Cs and a capacitor C2, and an inductor L2. One end of the secondary side coil Ls is connected to one end of the capacitor Cs. The other end of the capacitor Cs is respectively connected to one end of the capacitor C2 and one end of the inductor L2. The other end of the inductor L2, the other end of the secondary side coil Ls and the other end of the capacitor C2 are respectively connected to the controllable rectifier circuit.

[0015] Optionally, in the above wireless charging start control method, the step of obtaining the primary side coil current of the primary side device includes:

[0016] Obtain the mutual inductance value and the secondary side output current output from the secondary side circuit to the controllable rectifier circuit;

[0017] According to the mutual inductance value and the secondary side output current, use a first calculation formula to obtain the primary side coil current. The first calculation formula is:

[0018]

[0019] where, I p represents the amplitude of the primary side coil current i p ; M represents the mutual inductance value; I e represents the amplitude of the secondary side output current i e ; R e represents the equivalent impedance of the secondary side circuit; j is the imaginary part; ω represents the system operating angular frequency; where, L2 represents the inductance value of the inductor L2, C2 represents the capacitance value of the capacitor C2, Ls represents the inductance value of the secondary coil Ls, C s represents the capacitance value of the capacitor Cs.

[0020] Optionally, in the above wireless charging start control method, the step of obtaining the mutual inductance value includes:

[0021] When it is detected that an electromagnetic induction connection is established between the secondary device and the primary device, control the working mode of the controllable rectifier circuit to be a short - circuit mode;

[0022] When the working mode of the controllable rectifier circuit is the short - circuit mode, according to the preset constraint conditions, control the inverter circuit to output energy to the primary circuit and detect the mutual inductance value.

[0023] Optionally, in the above wireless charging start control method, the step of obtaining the current of the secondary coil of the secondary device includes:

[0024] According to the secondary output current, use the second calculation formula to obtain the current of the secondary coil; the second calculation formula is:

[0025] I s =(1 + jω·C2·R e -ω 2 ·L2·C2)·I e ;

[0026] where, I s represents the amplitude of the current i s of the secondary coil.

[0027] Optionally, in the above wireless charging start control method, the step of obtaining the secondary impedance angle according to the primary coil current and the secondary coil current includes:

[0028] According to the mutual inductance value, the primary coil current and the secondary coil current, use the third calculation formula to obtain the secondary impedance angle, and the third calculation formula is:

[0029]

[0030] where, β represents the secondary impedance angle; P out represents the system output power; η VA represents the efficiency required by the secondary device.

[0031] Optionally, before the step of judging whether the primary coil current is greater than a first preset value and whether the secondary impedance angle is less than a preset secondary impedance angle in the above wireless charging start control method, the method further includes:

[0032] According to the first preset value, using the third calculation formula, the preset secondary impedance angle is obtained.

[0033] Optionally, in the above wireless charging start control method, before the steps of determining whether the primary coil current is greater than the first preset value and whether the secondary impedance angle is less than the preset secondary impedance angle, the method further includes:

[0034] Collect the waveform of the secondary output current;

[0035] The step of controlling the impedance mode of the secondary device to be a capacitive impedance mode includes:

[0036] According to the zero-crossing point and amplitude of the waveform, phase-shift the secondary output voltage of the secondary device to control the impedance mode of the secondary device to be a capacitive impedance mode;

[0037] The step of controlling the impedance mode of the secondary device to be an inductive impedance mode or a resistive impedance mode includes:

[0038] According to the zero-crossing point and amplitude of the waveform, phase-shift the secondary output voltage of the secondary device to control the impedance mode of the secondary device to be an inductive impedance mode or a resistive impedance mode.

[0039] In a second aspect, the present invention provides a wireless charging system, the system includes:

[0040] A primary device;

[0041] A secondary device;

[0042] A control device respectively connected to the primary device and the secondary device;

[0043] Wherein, the control device includes a memory and a processor, and a wireless charging start control program is stored on the memory. When the wireless charging start control program is executed by the processor, the above-mentioned wireless charging start control method is implemented.

[0044] In a third aspect, the present invention provides a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by one or more processors, the above-mentioned wireless charging start control method is implemented.

[0045] One or more technical solutions provided by the present invention may have the following advantages or at least achieve the following technical effects:

[0046] A wireless charging startup control method, system and storage medium proposed by the present invention obtain the primary coil current and the secondary coil current when an electromagnetic induction connection is established between the secondary device and the primary device, and calculate the secondary impedance angle; determine whether the primary coil current is greater than a first preset value and whether the secondary impedance angle is less than a preset secondary impedance angle; thereby automatically select and control the impedance mode of the secondary device, and then based on this impedance mode, control the primary device and the secondary device to perform energy transfer to complete the charging startup process. The present invention controls the impedance mode of the secondary device to be a capacitive impedance mode, an inductive impedance mode or a resistive impedance mode for different situations, starts power transfer in an optimal state, and ensures that the system can achieve full power output during subsequent power transfer, effectively improving the power transfer ability of the electric vehicle wireless charging system under different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these provided drawings.

[0048] Figure 1 It is a schematic flowchart of the first embodiment of the wireless charging startup control method of the present invention;

[0049] Figure 2 It is a connection schematic diagram of the wireless charging system involved in each embodiment of the present invention;

[0050] Figure 3 For Figure 2 It is a schematic hardware structure diagram of the control device in

[0051] Figure 4 For Figure 2 It is a circuit connection schematic diagram of the primary device and the secondary device in

[0052] Figure 5 For Figure 4 It is a circuit connection schematic diagram of the secondary circuit and the controllable rectifier circuit in the secondary device of

[0053] The implementation, functional characteristics and advantages of the object of the present invention will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0055] It should be noted that in the present invention, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or system comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or system. Without further limitation, the elements defined by the statement "comprising..." do not preclude the presence of additional identical elements in the process, method, article or system comprising such element. Additionally, in the present invention, if there are descriptions involving "first", "second", etc., such descriptions of "first", "second", etc. are only for descriptive purposes and cannot be construed as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second" may expressly or implicitly include at least one such feature.

[0056] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Additionally, the technical solutions of each embodiment can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0057] Wireless charging is a new type of charging technology that has emerged in recent years. It can charge electronic devices within a certain space range without using charging cables. Its implementation method is mainly based on wireless power transfer technology, which uses principles such as magnetic resonance coupling, laser, and microwave to transmit electrical energy from the power source to the load in a non-contact manner, realizing wireless charging or power supply for the load. It has the advantages of being safe and reliable, flexible and convenient, environmentally friendly, and capable of working all-weather, and has received extensive attention.

[0058] Analysis of the prior art reveals that when wireless charging technology is applied in the field of electric vehicles, the working conditions are relatively complex. Due to differences in parameters such as the ground clearance, output voltage range, and charging power of different vehicle models, as well as the uncertainty of the load of the wireless charging system and the randomness of electric vehicle parking, high specifications are imposed on the circuit design and control strategy of the current wireless charging system. Based on this requirement, controllable circuits are provided on both the infrastructure side and vehicle-mounted side devices of the prior art wireless charging system to meet the charging function and charging performance requirements under different working conditions.

[0059] However, in the prior art wireless charging system, there are still some problems when controlling the controllable circuit. For example, in the charging startup stage, directly controlling the primary device to transfer energy to the secondary device cannot control the controllable circuit in combination with the actual state of the wireless charging system, resulting in the inability to achieve full-power output subsequently and affecting the power transfer efficiency. Another example is that under the constraint conditions of the parameter limit values given by the wireless charging system, to ensure full-power output of the system and at the same time ensure that the electrical parameters do not exceed the electrical stress of the devices, there is a corresponding value range for the duty cycle of the controllable circuit. However, as the coupling coefficient of the system increases, there gradually appears a situation where it is impossible to find a duty cycle value range that satisfies the parameter limit constraint conditions, that is, there is no D-value operating point. Therefore, in the prior art, in some working conditions, the wireless charging system cannot achieve full-power output and / or has poor power transfer efficiency.

[0060] In view of the technical problem that in the prior art wireless charging system, the controllable circuit is not controlled in combination with the actual state of the wireless charging system in the charging startup stage, affecting the power transfer efficiency, the present invention provides a wireless charging startup control method, and the general idea is as follows:

[0061] When it is detected that an electromagnetic induction connection is established between the secondary device and the primary device, obtain the primary coil current of the primary device and the secondary coil current of the secondary device; based on the primary coil current and the secondary coil current, obtain the secondary impedance angle; determine whether the primary coil current is greater than a first preset value and whether the secondary impedance angle is less than a preset secondary impedance angle; if the primary coil current is greater than the first preset value and the secondary impedance angle is less than the preset secondary impedance angle, then control the impedance mode of the secondary device to be a capacitive impedance mode; if the primary coil current is greater than the first preset value and the secondary impedance angle is greater than or equal to the preset secondary impedance angle, then control the impedance mode of the secondary device to be an inductive impedance mode or a resistive impedance mode; based on the impedance mode of the secondary device, control the primary device and the secondary device to perform energy transfer.

[0062] Through the above technical solution, when an electromagnetic induction connection is established between the secondary device and the primary device, the primary coil current and the secondary coil current are acquired, and the secondary impedance angle is calculated; it is determined whether the primary coil current is greater than a first preset value and whether the secondary impedance angle is less than a preset secondary impedance angle; thereby automatically selecting and controlling the impedance mode of the secondary device, and then based on this impedance mode, controlling the primary device and the secondary device to perform energy transfer to complete the charging startup process. In the present invention, for different situations, the impedance mode of the secondary device is controlled to be a capacitive impedance mode, an inductive impedance mode, or a resistive impedance mode, so as to start power transfer in an optimal state, ensure that the system can achieve full-power output during subsequent power transfer, and effectively improve the power transfer ability of the electric vehicle wireless charging system under different working conditions.

[0063] Embodiment 1

[0064] Referring to Figure 1 the flow schematic diagram of, a first embodiment of the wireless charging startup control method of the present invention is proposed. This wireless charging startup control method is applied to a wireless charging system, specifically to a wireless charging system in the field of electric vehicles.

[0065] As Figure 2 shown, it is a connection schematic diagram of the wireless charging system. The wireless charging system includes a primary device and a secondary device capable of achieving electromagnetic induction connection, and a control device respectively connected to the primary device and the secondary device. Those skilled in the art can understand that Figure 2 the structure shown in does not constitute a limitation to the wireless charging system of the present invention, and may include more or fewer components than shown, or combine some components, or have different component arrangements.

[0066] Specifically, the primary device can be arranged on the infrastructure side, the secondary device can be arranged on the vehicle-mounted side, the control device can be two control devices capable of achieving communication connection and respectively arranged on the infrastructure side and the vehicle-mounted side, or a control device arranged on the infrastructure side or the vehicle-mounted side and respectively communicating with the primary device and the secondary device. The control device can also be a terminal device or a network device capable of achieving network connection, and can be specifically set according to actual situations.

[0067] As Figure 3 shown, it is a hardware structure schematic diagram of the control device. The control device can include: a processor 1001, such as a CPU (Central Processing Unit, central processor), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. Those skilled in the art can understand that Figure 3The hardware structure shown does not limit the control device, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0068] Specifically, the communication bus 1002 is used to enable connection and communication between these components;

[0069] The user interface 1003 is used to connect to the client and communicate data with the client. The user interface 1003 may include an output unit, such as a display screen, and an input unit, such as a keyboard;

[0070] The network interface 1004 is used to connect to the background server and communicate data with the background server. The network interface 1004 may include an input / output interface, such as a standard wired interface, a wireless interface, such as a Wi-Fi interface;

[0071] The memory 1005 is used to store various types of data. Such data may include, for example, instructions for any application or method in the control device, as well as application-related data. The memory 1005 may be a high-speed RAM memory or a stable memory, such as a disk memory. Optionally, the memory 1005 may also be a storage device independent of the processor 1001;

[0072] Specifically, continuing to refer to Figure 3 , the memory 1005 may include an operating system, a network communication module, a user interface module, and a wireless charging start control program. Among them, the network communication module may be used to connect the primary device and the secondary device and communicate data with the primary device and the secondary device;

[0073] The processor 1001 is used to call the wireless charging start control program stored in the memory 1005 and perform the following operations:

[0074] When it is detected that an electromagnetic induction connection is established between the secondary device and the primary device, obtain the primary coil current of the primary device and the secondary coil current of the secondary device;

[0075] Obtain the secondary impedance angle based on the primary coil current and the secondary coil current;

[0076] Judge whether the primary coil current is greater than a first preset value and whether the secondary impedance angle is less than a preset secondary impedance angle;

[0077] If the primary coil current is greater than the first preset value and the secondary impedance angle is less than the preset secondary impedance angle, then control the impedance mode of the secondary device to be a capacitive impedance mode;

[0078] If the current of the primary side coil is greater than the first preset value and the impedance angle of the secondary side is greater than or equal to the preset secondary side impedance angle, then control the impedance mode of the secondary side device to be an inductive impedance mode or a resistive impedance mode;

[0079] Based on the impedance mode of the secondary side device, control the primary side device and the secondary side device to perform energy transfer.

[0080] Based on the above wireless charging system, the following combines Figure 1 the flow schematic diagram shown to describe in detail the wireless charging start control method of this embodiment.

[0081] Among them, the primary side device and the secondary side device of the wireless charging system are connected in accordance with Figure 4 the circuit connection schematic diagram shown. The primary side device includes an inverter circuit and a primary side circuit connected to each other, and the secondary side device includes a secondary side circuit and a controllable rectifier circuit connected to each other. The primary side device further includes a power supply DC connected to the inverter circuit, and the secondary side device further includes a load R connected to the controllable rectifier circuit. This power supply DC is a DC power supply, and this load R can be a storage battery or a power execution component.

[0082] Specifically, the primary side circuit includes an inductor L1, a capacitor Cp and a capacitor C1, and a primary side coil Lp. One end of the inductor L1 is connected to the inverter circuit, and the other end of the inductor L1 is respectively connected to one end of the capacitor Cp and one end of the capacitor C1. The other end of the capacitor Cp is connected to one end of the primary side coil Lp, and the other end of the primary side coil Lp and the other end of the capacitor C1 are respectively connected to the inverter circuit;

[0083] The secondary side circuit includes a secondary side coil Ls, a capacitor Cs and a capacitor C2, and an inductor L2. One end of the secondary side coil Ls is connected to one end of the capacitor Cs, and the other end of the capacitor Cs is respectively connected to one end of the capacitor C2 and one end of the inductor L2. The other end of the inductor L2, the other end of the secondary side coil Ls and the other end of the capacitor C2 are respectively connected to the controllable rectifier circuit.

[0084] More specifically, the secondary side circuit and the controllable rectifier circuit in the secondary side device are connected in accordance with Figure 5Connect according to the shown circuit connection diagram. The controllable rectifier circuit includes four switching devices, namely diode D1 and diode D2, switch tube S3 and switch tube S4. The other end of the inductor L2 is respectively connected to the positive electrode of the diode D1 and the drain of the switch tube S3. The other end of the capacitor C2 is respectively connected to the positive electrode of the diode D2 and the drain of the switch tube S4. The gates of the switch tube S3 and the switch tube S4 are connected to the control device. The negative electrodes of the diode D1 and the diode D2 are respectively connected to one end of the load R. The sources of the switch tube S3 and the switch tube S4 are respectively connected to the other end of the load R. A capacitor C0 is also connected in parallel across both ends of the load R.

[0085] Based on the above wireless charging system, combining the primary device and the secondary device therein, the wireless charging start control method of this embodiment is realized through the control device therein. The method may include the following steps:

[0086] Step S110: When it is detected that an electromagnetic induction connection is established between the secondary device and the primary device, obtain the primary coil current of the primary device and the secondary coil current of the secondary device.

[0087] Further, step S110 may include:

[0088] Step S111: When it is detected that an electromagnetic induction connection is established between the secondary device and the primary device, obtain the mutual inductance value and the secondary output current output from the secondary circuit to the controllable rectifier circuit.

[0089] Even further, step S111 may include:

[0090] Step S111.1: When it is detected that an electromagnetic induction connection is established between the secondary device and the primary device, control the working mode of the controllable rectifier circuit to be the short - circuit mode;

[0091] Specifically, when the secondary device approaches the primary device and the system is powered on, an electromagnetic induction connection is established between the secondary device and the primary device. At this time, the system enters the charging start stage, and the control device controls the working mode of the controllable rectifier circuit to be the short - circuit mode.

[0092] Step S111.2: When the working mode of the controllable rectifier circuit is the short - circuit mode, according to the preset constraint conditions, control the inverter circuit to output energy to the primary circuit and detect the mutual inductance value.

[0093] Specifically, after the control device controls the working mode of the controllable rectifier circuit to be the short - circuit mode, according to specific charging requirements, such as the charging power of the secondary device, that is, the system output power P out, and the specifically measured real-time parameters, such as the primary coil current and the secondary output current of the system, etc., to obtain the current mutual inductance value M.

[0094] As Figure 5 shown in the circuit connection schematic diagram, the controlled rectifier circuit in the secondary device is in a short-circuit state, and the secondary output current i e output from the secondary circuit in the secondary device to the controlled rectifier circuit returns to the secondary circuit through the switching devices in the controlled rectifier circuit, that is, switch tube S3 and switch tube S4, and the capacitor C0 that stores electrical energy in the secondary device directly supplies power to the load R. Since the controlled rectifier circuit is in a short-circuit state, the equivalent impedance R e of the secondary circuit = 0, and the system output voltage, that is, the secondary output voltage U e = 0, and the system does not do work on the load R. At this time, the measured value of the primary coil current i p in the primary device and the measured value of the secondary output current i e output from the secondary circuit in the secondary device to the controlled rectifier circuit can be collected in real time through a sampling circuit or a sampling device, so that the mutual inductance value M can be calculated. It should be noted that the calculation of the mutual inductance value M belongs to conventional technology and will not be elaborated here.

[0095] Step S111.3: Obtain the secondary output current output from the secondary circuit to the controlled rectifier circuit.

[0096] Specifically, when the working mode of the controlled rectifier circuit is the short-circuit mode, the system is in the charging start-up stage and there is no high-power energy transmission. At this time, the control device only controls the inverter circuit to output energy to the primary circuit, and the primary circuit does not start to output energy to the secondary circuit. Specifically, after the inverter circuit in the primary device performs inversion processing on the voltage of the power supply DC, it outputs the inverted voltage to the primary circuit. At this time, the inverter circuit has a low-voltage input, and it is necessary to ensure that the primary coil current i p meets the preset constraint conditions. For example, ensure that the measured value of the primary coil current i p is less than or equal to 10 A.

[0097] According to the mutual inductance value M, based on the system charging requirements and the current tolerance of the controlled rectifier circuit, the working range of the secondary output current i e output from the secondary circuit to the controlled rectifier circuit can be determined, and then the working range of the equivalent impedance R e of the secondary circuit in the secondary device can be obtained according to the following calculation formula:

[0098]

[0099] Among them, I e represents the amplitude of the secondary output current i e ; U e represents the secondary output voltage ue The amplitude value, when operating in a capacitive operating state, is expressed as follows:

[0100]

[0101] Where D represents the duty cycle of the controllable rectifier circuit,

[0102]

[0103] Where I out represents the system output current. Based on the above steps, the equivalent impedance R e of the secondary circuit in the secondary device and the secondary output current i e are obtained, and then the primary coil current can be continuously obtained.

[0104] Step S112: According to the mutual inductance value and the secondary output current, use the first calculation formula to obtain the primary coil current. The first calculation formula is:

[0105]

[0106] Where I p represents the amplitude value of the primary coil current i p ; M represents the mutual inductance value; I e represents the amplitude value of the secondary output current i e ; R e represents the equivalent impedance of the secondary circuit; j is the imaginary part; ω represents the system operating angular frequency; Where L2 represents the inductance value of inductor L2, C2 represents the capacitance value of capacitor C2, L s represents the inductance value of the secondary coil Ls, and C s represents the capacitance value of capacitor Cs.

[0107] Specifically, after obtaining the working range of the equivalent impedance R e of the secondary circuit and the working range of the secondary output current i e in step S111.3, using the first calculation formula, the working range of the primary coil current i p of the primary device can be continuously calculated, that is Figure 4 the current of the primary coil Lp in

[0108] Step S113: According to the secondary output current, use the second calculation formula to obtain the secondary coil current; the second calculation formula is:

[0109] I s =(1 + jω·C2·R e -ω 2 ·L2·C2)·I e ;

[0110] Among them, I s represents the magnitude of the current i in the secondary side coil s .

[0111] Specifically, after obtaining the working range of the equivalent impedance R of the secondary side circuit and the working range of the secondary side output current i e in step S111.3, when calculating the working range of the primary side coil current i e in step S112, the working range of the secondary side coil current i p can be continuously calculated by using the second calculation formula. That is s the current of the secondary side coil Ls in Figure 4 .

[0112] Step S120: Obtain the secondary side impedance angle according to the primary side coil current and the secondary side coil current

[0113] Furthermore, step S120 may include

[0114] Step S121: Obtain the secondary side impedance angle according to the mutual inductance value, the primary side coil current and the secondary side coil current by using the third calculation formula. The third calculation formula is

[0115]

[0116] Among them, β represents the secondary side impedance angle; P out represents the system output power; η VA represents the efficiency required by the secondary side device

[0117] Specifically, by using the third calculation formula, after calculating the working range of the primary side coil current i p and the working range of the secondary side coil current i s in step S110, the working range of the secondary side impedance angle β can be calculated

[0118] Step S130: Judge whether the primary side coil current is greater than a first preset value and whether the secondary side impedance angle is less than a preset secondary side impedance angle

[0119] Specifically, judge whether the magnitude I p of the primary side coil current i p is greater than the first preset value I p-ref , and whether the secondary side impedance angle is less than the preset secondary side impedance angle β ref .

[0120] In one implementation, before step S130, the method further includes

[0121] Step S170: According to the first preset value, use the third calculation formula to obtain the preset secondary impedance angle.

[0122] Each I p value has a corresponding maximum β value, jointly forming the limit constraint of the primary input current. Here, according to the first preset value I p-ref , using the following calculation formula:

[0123]

[0124] obtain the maximum secondary impedance angle β p-ref corresponding to the existence of the first preset value I max , so as to obtain the preset secondary impedance angle β ref ; in the formula, I e-max represents the maximum amplitude of the secondary output current i e , D max represents the maximum operating point of the duty cycle D of the controllable rectifier circuit, and I p-ref represents the first preset value of the primary coil current i p .

[0125] Therefore, the boundary conditions for the impedance mode control of the controllable rectifier circuit can be obtained as: I p > I p_ref & β < β ref .

[0126] Step S140: If the primary coil current is greater than the first preset value and the secondary impedance angle is less than the preset secondary impedance angle, control the impedance mode of the secondary device to be a capacitive impedance mode.

[0127] Specifically, if the primary side coil current is greater than a first preset value and the secondary side impedance angle is less than a preset secondary side impedance angle, then based on the waveform of the secondary side output current, the zero-crossing point and amplitude of the waveform are determined; then, based on the zero-crossing point and amplitude of the waveform, the secondary side output voltage of the secondary side device is phase-shifted to control the impedance mode of the secondary side device to be a capacitive impedance mode, and this capacitive impedance mode is the initial impedance mode of the system at the charging start stage. It is also possible to, after determining the zero-crossing point and amplitude of the waveform, adjust the duty cycle of the controllable rectifier circuit of the secondary side device based on the zero-crossing point and amplitude of the waveform to control the impedance mode of the secondary side device to be a capacitive impedance mode. It is also possible to, after determining the zero-crossing point and amplitude of the waveform, both phase-shift the secondary side output voltage of the secondary side device and adjust the duty cycle of the controllable rectifier circuit of the secondary side device based on the zero-crossing point and amplitude of the waveform, so as to control the impedance mode of the secondary side device to be a capacitive impedance mode. That is to say, a phase-shift control method and / or a duty cycle control method can be used to control the impedance mode of the secondary side device to be a capacitive impedance mode, and in practical applications, it can be selected according to specific circumstances.

[0128] At this time, the primary side coil current I p is greater than a first preset value I p-ref , and the secondary side impedance angle β is less than a preset secondary side impedance angle β ref , and the control device determines the zero-crossing point and amplitude based on the waveform of the secondary side output current i e , and then, based on the zero-crossing point and amplitude of this waveform, phase-shifts the secondary side output voltage u e to control the impedance mode of the secondary side device to be a capacitive impedance mode. Specifically, by controlling the switching transistor S3 and the switching transistor S4 to conduct respectively at the positive zero-crossing point or negative zero-crossing point of the secondary side output current i e , that is, the switching device realizes zero-voltage conduction, but non-zero-current turn-off. At this time, the switching device can operate in the ZVS (zero-voltage switching) state.

[0129] Step S150: If the primary side coil current is greater than a first preset value and the secondary side impedance angle is greater than or equal to the preset secondary side impedance angle, then control the impedance mode of the secondary side device to be an inductive impedance mode or a resistive impedance mode.

[0130] Specifically, if the primary side coil current is greater than the first preset value and the secondary side impedance angle is greater than or equal to the preset secondary side impedance angle, then based on the zero-crossing point and amplitude of the waveform of the secondary side output current, the phase shift of the secondary side output voltage of the secondary side device and / or the duty cycle of the controllable rectifier circuit of the secondary side device are adjusted to control the impedance mode of the secondary side device to be an inductive impedance mode or a resistive impedance mode. Whether it is an inductive impedance mode or a resistive impedance mode, it is the initial impedance mode of the system at the charging start stage. That is to say, when the primary side coil current is greater than the first preset value and the secondary side impedance angle is greater than or equal to the preset secondary side impedance angle, the phase shift of the secondary side output voltage of the secondary side device can be adjusted according to the zero-crossing point and amplitude of the waveform of the secondary side output current, the duty cycle of the controllable rectifier circuit of the secondary side device can also be adjusted, the phase shift of the secondary side output voltage of the secondary side device can also be performed, and the duty cycle of the controllable rectifier circuit of the secondary side device is adjusted, so as to control the impedance mode of the secondary side device to be an inductive impedance mode or a resistive impedance mode. In practical applications, it can be selected according to specific circumstances.

[0131] At this time, the primary side coil current I p is greater than the first preset value I p-ref , and the secondary side impedance angle β is greater than or equal to the preset secondary side impedance angle β ref . The control device determines the zero-crossing point and amplitude according to the waveform of the secondary side output current i e , and then, according to the zero-crossing point and amplitude of this waveform, the phase shift of the secondary side output voltage u e is performed to control the impedance mode of the secondary side device to be an inductive impedance mode or a resistive impedance mode. To control the impedance mode of the secondary side device to be an inductive impedance mode, specifically, the switching transistors S3 and S4 are controlled to turn off at the positive zero-crossing point or negative zero-crossing point of the secondary side output current i e , that is, the switching device realizes zero-current turn-off, but non-zero-voltage turn-on. At this time, the switching device can work in the ZCS (zero-current switching) state. To control the impedance mode of the secondary side device to be a resistive impedance mode, specifically, by controlling the turn-on time and turn-off time of the switching transistors S3 and S4, the secondary side output voltage u e and the secondary side output current i e are in the same phase, and the imaginary part of the equivalent impedance R e of the secondary side circuit is zero. At this time, the switching device works in the hard switching state.

[0132] Step S160: Based on the impedance mode of the secondary side device, control the primary side device and the secondary side device to perform energy transfer.

[0133] Further, step S160 may include:

[0134] Step S161: Based on the impedance mode of the secondary device, control the primary circuit to transmit the energy, and control the secondary circuit to receive the energy, so as to achieve energy transmission between the primary device and the secondary device.

[0135] Specifically, after the control device controls the impedance mode of the secondary device to be the above-mentioned initial impedance mode, the control device controls the primary device and the secondary device to perform energy transmission based on the impedance mode of the secondary device. That is, based on the impedance mode of the secondary device and the energy output from the inverter circuit to the primary circuit, the primary circuit is controlled to transmit the energy, and the secondary circuit is controlled to receive the energy, so as to realize the energy transmission between the primary device and the secondary device. At this point, the system starts power transmission and enters the power transmission stage from the charging startup stage.

[0136] The wireless charging startup control method provided in this embodiment obtains the estimated working range of the working parameters of the system, including the primary coil current and the secondary impedance angle, when it is detected that an electromagnetic induction connection is established between the secondary device and the primary device, and then determines the initial impedance mode of the secondary device when it is determined that the preset startup condition is met based on the calculated range value, that is, when the primary coil current is greater than a first preset value and the secondary impedance angle is less than the preset secondary impedance angle, it is determined that the initial impedance mode of the secondary device is a capacitive impedance mode, and when the primary coil current is greater than the first preset value and the secondary impedance angle is greater than or equal to the preset secondary impedance angle. , determine the initial impedance mode of the secondary device as an inductive impedance mode or a resistive impedance mode; thereby controlling the primary device and the secondary device to start energy transmission based on the initial impedance mode, and entering the power transmission stage from the charging start stage; subsequently, during the process of energy transmission between the primary device and the secondary device, when it is determined that the system meets the impedance mode switching condition, the impedance mode of the secondary device is switched to control the secondary device to transmit energy in the most reasonable impedance mode, ensuring that the system is in a full power output state, and effectively improving the power transmission capacity of the electric vehicle wireless charging system when used under different working conditions. The present invention realizes the effect of combining the actual state of the wireless charging system, flexibly controlling the impedance mode of the secondary device, and achieving full power output.

[0137] Embodiment 2

[0138] Based on the same inventive concept, Figures 2 to 5 , a first embodiment of the wireless charging system of the present invention is proposed. The system can be a wireless charging system applied in the field of electric vehicles.

[0139] Combine the following Figure 2 The connection schematic diagram shown in the figure describes in detail the wireless charging system provided by this embodiment, and the system may include:

[0140] Primary side device;

[0141] Secondary side device;

[0142] A control device respectively connected to the primary side device and the secondary side device.

[0143] Specifically, the primary side device and the secondary side device can achieve electromagnetic induction connection. The primary side device can be arranged on the infrastructure side, and the secondary side device can be arranged on the vehicle-mounted side. The control device can be two control devices that can achieve communication connection and are respectively arranged on the infrastructure side and the vehicle-mounted side, or a control device arranged on the infrastructure side or the vehicle-mounted side and respectively communicating with the primary side device and the secondary side device. The control device can also be a terminal device or a network device that can achieve network connection, and can be specifically set according to the actual situation.

[0144] Those skilled in the art can understand that Figure 2 the structure shown in does not constitute a limitation to the wireless charging system of the present invention, and may include more or fewer components than shown, or combine some components, or have different component arrangements.

[0145] Further, as Figure 3 shown in the schematic diagram of the hardware structure; the control device may include a processor and a memory. A wireless charging start control program is stored in the memory. When the wireless charging start control program is executed by the processor, all or part of the steps of each embodiment of the wireless charging start control method of the present invention are realized. It can be understood that the control device may further include a communication bus, a user interface, and a network interface. Those skilled in the art can understand that Figure 3 the hardware structure shown in does not constitute a limitation to the control device, and may include more or fewer components than shown, or combine some components, or have different component arrangements.

[0146] Among them, the communication bus is used to realize the connection and communication between these components.

[0147] The user interface is used to connect to the client and communicate with the client. The user interface may include an output unit, such as a display screen, and an input unit, such as a keyboard.

[0148] The network interface is used to connect to the background server and communicate with the background server. The network interface may include an input / output interface, such as a standard wired interface, a wireless interface, such as a Wi-Fi interface.

[0149] The memory is used to store various types of data, which may include, for example, instructions for any application program or method in the control device, as well as application-related data. The memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk. Optionally, the memory can also be a storage device independent of the processor.

[0150] The processor is used to call the wireless charging start control program stored in the memory and execute the wireless charging start control method as described above. The processor can be an application specific integrated circuit (ASIC), digital signal processor (DSP), digital signal processing device (DSPD), programmable logic device (PLD), field programmable gate array (FPGA), controller, microcontroller, microprocessor or other electronic components, and is used to execute all or part of the steps of each embodiment of the wireless charging start control method as described above.

[0151] Furthermore, as Figure 4 shown in the circuit connection schematic diagram; the secondary device includes a secondary circuit and a controlled rectifier circuit connected to each other, and the primary device includes an inverter circuit and a primary circuit connected to each other; the primary device further includes a power supply DC connected to the inverter circuit, and the secondary device further includes a load R connected to the controlled rectifier circuit. The power supply DC is a DC power supply, and the load R can be a storage battery or a power execution component.

[0152] Furthermore, the primary side circuit includes an inductor L1, a capacitor Cp, a capacitor C1, and a primary side coil Lp. One end of the inductor L1 is connected to the inverter circuit, and the other end of the inductor L1 is respectively connected to one end of the capacitor Cp and one end of the capacitor C1. The other end of the capacitor Cp is connected to one end of the primary side coil Lp. The other end of the primary side coil Lp and the other end of the capacitor C1 are respectively connected to the inverter circuit;

[0153] The secondary side circuit includes a secondary side coil Ls, a capacitor Cs, a capacitor C2, and an inductor L2. One end of the secondary side coil Ls is connected to one end of the capacitor Cs. The other end of the capacitor Cs is respectively connected to one end of the capacitor C2 and one end of the inductor L2. The other end of the inductor L2, the other end of the secondary side coil Ls, and the other end of the capacitor C2 are respectively connected to the controlled rectifier circuit.

[0154] Furthermore, as Figure 5 shown in the circuit connection schematic diagram; the controlled rectifier circuit includes four switching devices, namely diode D1 and diode D2, switch tube S3 and switch tube S4. The other end of the inductor L2 is respectively connected to the positive electrode of the diode D1 and the drain of the switch tube S3. The other end of the capacitor C2 is respectively connected to the positive electrode of the diode D2 and the drain of the switch tube S4. The gates of the switch tube S3 and the switch tube S4 are connected to the control device. The negative electrodes of the diode D1 and the diode D2 are respectively connected to one end of the load R. The sources of the switch tube S3 and the switch tube S4 are respectively connected to the other end of the load R. A capacitor C0 is also connected in parallel across both ends of the load R and can be used to store electrical energy.

[0155] It should be noted that the functions that can be achieved by each device in the wireless charging system provided in this embodiment and the corresponding technical effects can be referred to the description of the specific implementation in the embodiment of the wireless charging start control method of the present invention. For the sake of brevity of the specification, it will not be elaborated here.

[0156] Embodiment III

[0157] Based on the same inventive concept, this embodiment provides a computer-readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card-type memory (e.g., SD or DX memory, etc.), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a magnetic disk, an optical disk, a server, etc. A computer program is stored on the storage medium, and the computer program can be executed by one or more processors. When the computer program is executed by the processor, all or part of the steps of the wireless charging start control method of the present invention in various embodiments can be implemented.

[0158] It should be noted that the serial numbers of the above embodiments of the present invention are only for description and do not represent the superiority or inferiority of the embodiments.

[0159] The above are only the optional embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention under the inventive concept of the present invention, or directly or indirectly applied to other related technical fields, are all included in the patent protection scope of the present invention.

Claims

1. A wireless charging startup control method, characterized in that, Applied to a wireless charging system, the system includes a primary device and a secondary device, and the method includes: When it is detected that an electromagnetic induction connection is established between the secondary device and the primary device, obtain the primary coil current of the primary device and the secondary coil current of the secondary device; Obtain the secondary impedance angle according to the primary coil current and the secondary coil current; Judge whether the primary coil current is greater than a first preset value, and whether the secondary impedance angle is less than a preset secondary impedance angle; If the primary coil current is greater than the first preset value and the secondary impedance angle is less than the preset secondary impedance angle, control the impedance mode of the secondary device to be a capacitive impedance mode; If the primary coil current is greater than the first preset value and the secondary impedance angle is greater than or equal to the preset secondary impedance angle, control the impedance mode of the secondary device to be an inductive impedance mode or a resistive impedance mode; Based on the impedance mode of the secondary device, control the primary device and the secondary device to perform energy transfer.

2. The wireless charging start control method according to claim 1, wherein The primary device includes an inverter circuit and a primary circuit connected to each other, and the secondary device includes a secondary circuit and a controllable rectifier circuit connected to each other; The primary circuit includes an inductor L1, a capacitor Cp and a capacitor C1, and a primary coil Lp. One end of the inductor L1 is connected to the inverter circuit, and the other end of the inductor L1 is respectively connected to one end of the capacitor Cp and one end of the capacitor C1. The other end of the capacitor Cp is connected to one end of the primary coil Lp, and the other end of the primary coil Lp and the other end of the capacitor C1 are respectively connected to the inverter circuit; The secondary circuit includes a secondary coil Ls, a capacitor Cs and a capacitor C2, and an inductor L2. One end of the secondary coil Ls is connected to one end of the capacitor Cs, and the other end of the capacitor Cs is respectively connected to one end of the capacitor C2 and one end of the inductor L2. The other end of the inductor L2, the other end of the secondary coil Ls and the other end of the capacitor C2 are respectively connected to the controllable rectifier circuit.

3. The wireless charging start control method according to claim 2, wherein The step of obtaining the primary coil current of the primary device includes: Obtain the mutual inductance value and the secondary output current output from the secondary circuit to the controllable rectifier circuit; According to the mutual inductance value and the secondary output current, use a first calculation formula to obtain the primary coil current, and the first calculation formula is: Among them, I p represents the amplitude of the primary side coil current i p ; M represents the mutual inductance value; I e represents the amplitude of the secondary side output current i e ; R e represents the equivalent impedance of the secondary side circuit; j is the imaginary part; ω represents the system operating angular frequency; Among them, L2 represents the inductance value of the inductor L2, C2 represents the capacitance value of the capacitor C2, L s represents the inductance value of the secondary side coil Ls, C s represents the capacitance value of the capacitor Cs.

4. The wireless charging start control method according to claim 3, characterized in that, The step of obtaining the mutual inductance value includes: When it is detected that an electromagnetic induction connection is established between the secondary device and the primary device, control the working mode of the controllable rectifier circuit to be a short - circuit mode; When the working mode of the controllable rectifier circuit is the short - circuit mode, according to preset constraint conditions, control the inverter circuit to output energy to the primary circuit and detect the mutual inductance value.

5. The wireless charging start control method according to claim 3, characterized in that, The step of obtaining the secondary coil current of the secondary device includes: According to the secondary output current, use a second calculation formula to obtain the secondary coil current; the second calculation formula is: I s = (1 + jω·C2·R e - ω 2 ·L2·C2)·I e ; Among them, I s represents the amplitude of the secondary side coil current i s .

6. The wireless charging start control method according to claim 5, characterized in that, The step of obtaining the secondary impedance angle according to the primary coil current and the secondary coil current includes: Based on the mutual inductance value, the primary coil current, and the secondary coil current, use the third calculation formula to obtain the secondary impedance angle. The third calculation formula is as follows: Among them, β represents the secondary side impedance angle; P out represents the system output power; η VA represents the efficiency required by the secondary side device.

7. The wireless charging start control method according to claim 6, characterized in that Before the steps of determining whether the primary coil current is greater than a first preset value and whether the secondary impedance angle is less than a preset secondary impedance angle, the method further includes: Based on the first preset value, use the third calculation formula to obtain the preset secondary impedance angle.

8. The wireless charging start control method according to claim 3, wherein Before the steps of determining whether the primary coil current is greater than a first preset value and whether the secondary impedance angle is less than a preset secondary impedance angle, the method further includes: Collect the waveform of the secondary output current; The step of controlling the impedance mode of the secondary device to be a capacitive impedance mode includes: Based on the zero-crossing point and amplitude of the waveform, phase-shift the secondary output voltage of the secondary device to control the impedance mode of the secondary device to be a capacitive impedance mode; The step of controlling the impedance mode of the secondary device to be an inductive impedance mode or a resistive impedance mode includes: Based on the zero-crossing point and amplitude of the waveform, phase-shift the secondary output voltage of the secondary device to control the impedance mode of the secondary device to be an inductive impedance mode or a resistive impedance mode.

9. A wireless charging system, characterized in that, The system includes: A primary device; A secondary device; A control device respectively connected to the primary device and the secondary device; Wherein, the control device includes a memory and a processor. A wireless charging start control program is stored on the memory. When the wireless charging start control program is executed by the processor, the wireless charging start control method according to any one of claims 1 to 8 is implemented.

10. A computer-readable storage medium, characterized in that, A computer program is stored on the storage medium. When the computer program is executed by one or more processors, the wireless charging start control method according to any one of claims 1 to 8 is implemented.

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