Secondary-side impedance mode control method, system and storage medium

Abstract

The present invention discloses a secondary-side impedance mode control method, system and storage medium, relating to the technical field of wireless charging. The method includes: obtaining the current impedance mode and secondary-side impedance angle of a secondary-side device, and calculating the primary-side input current; determining whether the primary-side input current is greater than or equal to a second preset value; if the primary-side input current is greater than or equal to the second preset value, controlling the secondary-side device to switch to the next impedance mode according to the current impedance mode of the secondary-side device and a preset switching sequence; and controlling the secondary-side device to receive the energy transmitted by the primary-side device based on the impedance mode after the secondary-side device switches. The present invention solves the problems in the prior art that the control flexibility is poor, affecting the power transmission magnitude and efficiency, and realizes the effect of automatically switching the impedance mode of the secondary-side device and improving the power transmission ability.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless charging, and in particular, to a secondary-side impedance mode 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 provided on both the infrastructure side and vehicle-mounted side devices 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 power transmission stage, the control flexibility of the controllable circuit is poor, resulting in the inability to achieve full power output, affecting the size and efficiency of power transmission. Summary of the Invention

[0003] The main purpose of the present invention is to provide a secondary-side impedance mode control method, system, and storage medium, aiming to solve the technical problem that in the existing wireless charging system, the control flexibility of the controllable circuit is poor in the power transmission stage, affecting the size and efficiency of power transmission.

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

[0005] In a first aspect, the present invention provides a secondary-side impedance mode control method applied to a wireless charging system. The system includes a primary-side device and a secondary-side device, and the primary-side device and the secondary-side device are electromagnetically inductively connected. The primary-side device includes an inverter circuit and a primary-side circuit connected to each other. The method includes:

[0006] Obtain the current impedance mode and secondary-side impedance angle of the secondary-side device;

[0007] According to the secondary-side impedance angle, obtain the primary-side input current output from the inverter circuit to the primary-side circuit in the primary-side device;

[0008] Judge whether the primary-side input current is greater than or equal to a second preset value;

[0009] If the primary-side input current is greater than or equal to the second preset value, then according to the current impedance mode of the secondary-side device and a preset switching sequence, control the secondary-side device to switch to the next impedance mode; wherein, the preset switching sequence is a capacitive impedance mode, an inductive impedance mode, and a resistive impedance mode arranged in sequence;

[0010] Based on the impedance mode of the secondary device after switching, control the secondary device to receive the energy transmitted by the primary device.

[0011] Optionally, in the above secondary impedance mode control method, after the step of determining whether the primary input current is greater than or equal to a second preset value, the method further includes:

[0012] If the primary input current is less than the second preset value, control the secondary device to receive the energy transmitted by the primary device based on the current impedance mode of the secondary device.

[0013] Optionally, in the above secondary impedance mode control method, the secondary device includes a secondary circuit and a controllable rectifier circuit connected to each other;

[0014] The step of obtaining the current impedance mode and the secondary impedance angle of the secondary device includes:

[0015] During the energy transfer between the primary device and the secondary device, collect the primary coil current of the primary device and the secondary coil current of the secondary device;

[0016] Determine whether the primary coil current reaches a first preset value;

[0017] If the primary coil current reaches the first preset value, obtain the current impedance mode of the secondary device;

[0018] Obtain the secondary impedance angle of the secondary device according to the primary coil current and the secondary coil current.

[0019] Optionally, in the above secondary impedance mode control method, 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;

[0020] 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;

[0021] The step of obtaining the secondary impedance angle of the secondary device according to the primary coil current and the secondary coil current includes:

[0022] Detect the mutual inductance value;

[0023] According to the mutual inductance value, the primary coil current, and the secondary coil current, use the second calculation formula to obtain the secondary impedance angle of the secondary device. The second calculation formula is:

[0024]

[0025] where β represents the secondary impedance angle; P out represents the system output power; η VA represents the efficiency required by the secondary device; ω represents the system operating angular frequency; M represents the mutual inductance value; I p represents the amplitude of the primary coil current i p ; I s represents the amplitude of the secondary coil current i s .

[0026] Optionally, in the above secondary impedance mode control method, the step of obtaining the primary input current output from the inverter circuit to the primary circuit in the primary device according to the secondary impedance angle includes:

[0027] According to the secondary impedance angle, use the third calculation formula to obtain the primary input current output from the inverter circuit to the primary circuit in the primary device. The third calculation formula is:

[0028]

[0029] where i in represents the primary input current; Γ represents the rate of change of the inductance value L of the primary coil Lp p ; L1 represents the inductance value of the inductor L1; I p represents the amplitude of the primary coil current i p ; M represents the mutual inductance value; I s represents the amplitude of the secondary coil current i s ; β represents the secondary impedance angle; ω represents the system operating angular frequency; η VA represents the efficiency required by the secondary device; j is the imaginary part.

[0030] Optionally, in the above secondary impedance mode control method, the step of, if the primary input current is greater than or equal to the second preset value, controlling the secondary device to switch to the next impedance mode according to the current impedance mode and the preset switching sequence of the secondary device further includes:

[0031] Collect the secondary output current output from the secondary circuit to the controlled rectifier circuit in the secondary device;

[0032] Determine whether the secondary side output current is greater than or equal to a third preset value;

[0033] If the primary side input current is greater than or equal to a second preset value, or the secondary side output current is greater than or equal to a third preset value, then control the secondary side device to switch to the next impedance mode according to the current impedance mode of the secondary side device and the preset switching sequence.

[0034] Optionally, in the above secondary side impedance mode control method, before the step of controlling the secondary side device to switch to the next impedance mode according to the current impedance mode of the secondary side device and the preset switching sequence, the method further includes:

[0035] Collect the waveform of the secondary side output current output from the secondary side circuit of the secondary side device to the controllable rectifier circuit;

[0036] The step of controlling the secondary side device to switch to the next impedance mode includes:

[0037] According to the zero-crossing point and amplitude of the waveform, phase-shift the secondary side output voltage of the secondary side device, and control the impedance mode of the secondary side device to switch to the next impedance mode.

[0038] Optionally, in the above secondary side impedance mode control method, after the step of determining whether the primary side input current is greater than or equal to a second preset value, the method further includes:

[0039] When the current impedance mode is a resistive impedance mode, if the primary side input current is greater than or equal to a second preset value, then control the secondary side device to stop receiving the energy transmitted by the primary side device or receive the energy transmitted by the primary side device in a low power state.

[0040] In a second aspect, the present invention provides a wireless charging system, the system includes:

[0041] A primary side device;

[0042] A secondary side device;

[0043] A control device respectively connected to the primary side device and the secondary side device;

[0044] Wherein, the control device includes a memory and a processor, and a secondary side impedance mode control program is stored on the memory. When the secondary side impedance mode control program is executed by the processor, the above secondary side impedance mode control method is implemented.

[0045] 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 secondary side impedance mode control method is implemented.

[0046] One or more of the above technical solutions provided by the present invention may have the following advantages or at least achieve the following technical effects:

[0047] A secondary-side impedance mode control method, system, and storage medium proposed by the present invention calculate the primary input current output from the inverter circuit to the primary circuit based on the obtained secondary-side impedance angle; when it is determined that the primary input current is greater than or equal to a second preset value, the secondary-side device is controlled to switch to the next impedance mode according to the current impedance mode and the preset switching sequence; and based on the switched impedance mode, the secondary-side device is controlled to receive the energy transmitted by the primary-side device, realizing real-time and automatic switching of the impedance mode of the secondary-side device. The present invention collects the system operating parameters in real time during the power transmission stage of the wireless charging system, automatically switches the impedance mode of the secondary-side device, realizes full-power output under different working conditions, effectively improves the power transmission ability of the electric vehicle wireless charging system when applied under different working conditions, and improves the control flexibility and power transmission efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] 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, and those of ordinary skill in the art can obtain other drawings based on these provided drawings without creative efforts.

[0049] Figure 1 It is a schematic flowchart of the first embodiment of the secondary-side impedance mode control method of the present invention;

[0050] Figure 2 It is a schematic connection diagram of the wireless charging system involved in each embodiment of the present invention;

[0051] Figure 3 For Figure 2 It is a schematic hardware structure diagram of the control device in

[0052] Figure 4 For Figure 2 It is a schematic circuit connection diagram of the primary-side device and the secondary-side device in

[0053] Figure 5 For Figure 4 It is a schematic circuit connection diagram of the secondary-side circuit and the controlled rectifier circuit in the secondary-side device of

[0054] The realization, functional features, and advantages of the object of the present invention will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] 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. Obviously, 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 any creative efforts shall fall within the protection scope of the present invention.

[0056] It should be noted that in the present invention, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or system including a series of elements not only includes those elements but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or system. Without further limitations, the elements defined by the statement "include..." do not exclude the presence of additional identical elements in the process, method, article or system including 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 specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second" may explicitly or implicitly include at least one such feature.

[0057] 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 fact that those of ordinary skill in the art can implement it. 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 protection scope required by the present invention.

[0058] 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 transmission technology, and uses principles such as magnetic resonance coupling, laser, and microwave to transmit electrical energy from the power source end to the load end 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 wide attention.

[0059] 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 - specification requirements 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 - side devices of the prior - art wireless charging system to meet the charging function and charging performance requirements under different working conditions.

[0060] However, in the prior - art wireless charging system, there are still some problems when controlling the controllable circuit. For example, during the power transmission stage, power is transmitted in a single state all the time, resulting in poor control flexibility of the system, which leads to the inability to achieve full - power output and affects the magnitude and efficiency of power transmission.

[0061] Also, under the constraint conditions of the parameter limits 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, resulting in poor power - transmission efficiency.

[0062] In view of the technical problem of poor power - transmission efficiency in the prior - art wireless charging system, the present invention provides a secondary - side impedance - mode control method, and the general idea is as follows:

[0063] Obtain the current impedance mode and secondary - side impedance angle of the secondary - side device; based on the secondary - side impedance angle, obtain the primary - side input current output from the inverter circuit in the primary - side device to the primary - side circuit; determine whether the primary - side input current is greater than or equal to a second preset value; if the primary - side input current is greater than or equal to the second preset value, then control the secondary - side device to switch to the next impedance mode according to the current impedance mode of the secondary - side device and the preset switching sequence; where the preset switching sequence is the capacitive impedance mode, inductive impedance mode, and resistive impedance mode arranged in sequence; based on the impedance mode after the secondary - side device switches, control the secondary - side device to receive the energy transmitted by the primary - side device.

[0064] Through the above technical solution, the primary input current output from the inverter circuit to the primary circuit is calculated based on the obtained secondary side impedance angle; when it is determined that the primary input current is greater than or equal to the second preset value, according to the current impedance mode and the preset switching sequence, the secondary side device is controlled to switch to the next impedance mode; and based on the switched impedance mode, the secondary side device is controlled to receive the energy transmitted by the primary side device, so as to realize the real-time and automatic switching of the impedance mode of the secondary side device. The present invention collects the system operating parameters in real time during the power transmission stage of the wireless charging system, automatically switches the impedance mode of the secondary side device, realizes full power output under different working conditions, effectively improves the power transmission ability of the electric vehicle wireless charging system when applied under different working conditions, and improves the control flexibility and power transmission efficiency of the system.

[0065] Embodiment 1

[0066] Referring to Figure 1 the flow schematic diagram, the first embodiment of the secondary side impedance mode control method of the present invention is proposed. The secondary side impedance mode control method is applied to a wireless charging system, and specifically applied to a wireless charging system in the field of electric vehicles.

[0067] As Figure 2 shown, it is a connection schematic diagram of the wireless charging system. The wireless charging system includes a primary side device and a secondary side device capable of realizing electromagnetic induction connection, and a control device respectively connected to the primary side device and the secondary side device. Those skilled in the art can understand that Figure 2 the structure shown in

[0068] does not constitute a limitation to the wireless charging system of the present invention, and may include more or fewer components than shown in the figure, or combine some components, or different component arrangements.

[0069] As Figure 3 shown, it is a hardware structure schematic diagram of the control device. The control device may 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.

[0070] Specifically, the communication bus 1002 is used to implement connection communication between these components;

[0071] The user interface 1003 is used to connect to the client and perform data communication 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;

[0072] The network interface 1004 is used to connect to the background server and perform data communication with the background server. The network interface 1004 may include an input / output interface, such as a standard wired interface and a wireless interface such as a Wi-Fi interface;

[0073] The memory 1005 is used to store various types of data. These 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;

[0074] 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 secondary-side impedance mode control program. Among them, the network communication module may be used to connect the primary-side device and the secondary-side device and perform data communication with the primary-side device and the secondary-side device;

[0075] The processor 1001 is used to call the secondary-side impedance mode control program stored in the memory 1005 and perform the following operations:

[0076] Obtain the current impedance mode and secondary-side impedance angle of the secondary-side device;

[0077] According to the secondary-side impedance angle, obtain the primary-side input current output from the inverter circuit in the primary-side device to the primary-side circuit;

[0078] Determine whether the primary-side input current is greater than or equal to a second preset value;

[0079] If the primary-side input current is greater than or equal to the second preset value, control the secondary-side device to switch to the next impedance mode according to the current impedance mode of the secondary-side device and the preset switching sequence; where the preset switching sequence is the capacitive impedance mode, inductive impedance mode, and resistive impedance mode arranged in sequence;

[0080] Based on the impedance mode after the secondary-side device switches, control the secondary-side device to receive the energy transmitted by the primary-side device.

[0081] Based on the above wireless charging system, the following combines Figure 1 with the process schematic diagram shown to describe in detail the secondary side impedance mode control method of this embodiment.

[0082] Among them, the primary side device and the secondary side device of the wireless charging system are connected according to the Figure 4 circuit connection schematic diagram shown. The primary side device includes an inverter circuit and a primary side circuit connected to each other. 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.

[0083] Specifically, the primary side circuit includes an inductor L1, a capacitor Cp and a capacitor C1, as well as 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;

[0084] The secondary side circuit includes a secondary side coil Ls, a capacitor Cs and a capacitor C2, as well as 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.

[0085] More specifically, the secondary side circuit and the controllable rectifier circuit in the secondary side device are connected according to the Figure 5 circuit connection schematic diagram shown. 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 at both ends of the load R and can be used to store electric energy.

[0086] Based on the above wireless charging system, combining the primary device and the secondary device therein, the secondary impedance mode control method of this embodiment is implemented through the control device therein. The method may include the following steps:

[0087] Step S210: Obtain the current impedance mode and the secondary impedance angle of the secondary device.

[0088] Further, step S210 may include:

[0089] Step S211: During the energy transfer between the primary device and the secondary device, collect the primary coil current of the primary device and the secondary coil current of the secondary device.

[0090] Specifically, when it is detected that the primary device and the secondary device establish an electromagnetic induction connection, and the primary device transfers energy while the secondary device receives the energy, it is confirmed that the primary device and the secondary device are in the power transfer stage. Based on this stage, during the energy transfer between the primary device and the secondary device, the primary coil current i p of the primary device can be collected through a sampling circuit or a sampling device, and the amplitude I p of the primary coil current i p can be calculated. At the same time, the secondary coil current i s of the secondary device can also be collected through a sampling circuit or a sampling device, and the amplitude I s of the secondary coil current i s can be calculated.

[0091] Step S212: Determine whether the primary coil current reaches a first preset value.

[0092] Since the primary input current i in will decrease as I p increases and increase as β increases. If the amplitude I in of the primary input current i in is to meet the limit constraint, I p needs to have a minimum limit and β needs to have a maximum limit. In actual calculation, according to the preset parameters of the system, the limit constraint of I in can be obtained, and based on this limit constraint, when the system load and system parameters are determined, the amplitude U in of the primary input voltage u in output from the inverter circuit in the primary device to the primary circuit is used to obtain the limit constraint of I p . Through the above derivation, by detecting the secondary impedance angle β, the detection of the primary input current i in can be realized, and further determine whether the primary input current i in exceeds the limit constraint.

[0093] It can be seen from this that the primary side input current i in is related to the amplitude I p of the variable primary side coil current i p and the secondary side impedance angle β. Therefore, the limit constraint of the primary side input current i in can be correspondingly regarded as the limit constraint on the secondary side impedance angle β. To meet the limit constraint of the primary side input current i in , the value of I p should not be lower than the first preset value. For example, the first preset value can be a parameter according to system requirements. When the limit constraint I in of the primary side input current i in ≤45A is satisfied, after listing the limits of different I p and the corresponding β, the β corresponding to I p is obtained. At this time, if the value corresponding to I p , such as 20A, is the first preset value, the corresponding β is 0. That is to say, it is necessary to continue to collect the real-time working parameters of the system and detect the β value when the primary side coil current I p ≥20A to realize the detection of the I in value, and then judge whether I in exceeds the limit constraint, that is, enter step S220.

[0094] Step S213: If the primary side coil current reaches the first preset value, obtain the current impedance mode of the secondary side device.

[0095] Specifically, if the primary side coil current reaches the first preset value, the control device obtains the current impedance mode of the secondary side device.

[0096] Step S214: Obtain the secondary side impedance angle of the secondary side device according to the primary side coil current and the secondary side coil current.

[0097] Furthermore, step S214 may include:

[0098] Step S214.1: Detect the mutual inductance value;

[0099] Specifically, the mutual inductance value can be directly detected by a sampling circuit or a sampling device, and the control device correspondingly receives the detected mutual inductance value M.

[0100] Step S214.2: Obtain the secondary side impedance angle of the secondary side device according to the mutual inductance value, the primary side coil current and the secondary side coil current.

[0101] Specifically, according to the mutual inductance value, the primary side coil current and the secondary side coil current, the secondary side impedance angle of the secondary side device is obtained by using the second calculation formula, and the second calculation formula is:

[0102]

[0103] 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; ω represents the system operating angular frequency; M represents the mutual inductance value; I p represents the amplitude of the primary-side coil current i p ; I s represents the amplitude of the secondary-side coil current i s .

[0104] More specifically, the system output power P out is set according to the actual charging requirement, and then the mutual inductance value M, the amplitude I p of the primary-side coil current i p and the amplitude I s of the secondary-side coil current i s are substituted into the second calculation formula, and the secondary-side impedance angle β can be obtained.

[0105] Step S220: Obtain the primary-side input current output from the inverter circuit in the primary-side device to the primary-side circuit according to the secondary-side impedance angle.

[0106] Furthermore, step S220 may include:

[0107] Step S221: According to the secondary-side impedance angle, use the third calculation formula to obtain the primary-side input current output from the inverter circuit in the primary-side device to the primary-side circuit, and the third calculation formula is:

[0108]

[0109] where i in represents the primary-side input current; Γ represents the change rate of the inductance value L p of the primary-side coil Lp; L1 represents the inductance value of the inductor L1; I p represents the amplitude of the primary-side coil current i p ; M represents the mutual inductance value; I s represents the amplitude of the secondary-side coil current i s ; β represents the secondary-side impedance angle; ω represents the system operating angular frequency; η VA represents the efficiency required by the secondary-side device; j is the imaginary part.

[0110] Among them, the inductance value L p of the primary-side coil Lp is specifically the self-inductance value designed for the primary-side coil at the system fixed operating frequency point, that is, the inductance value of the primary-side coil Lp at the minimum coupling coefficient kmin; P outSpecifically, it is the set system output power, where ω, L1, L p , Γ are all fixed values, and η VA is a parameter with a relatively small variation. After designing the electrical parameters of the system, the range or minimum value of the efficiency η VA can be estimated. Substituting the above specific values into the third calculation formula, the primary input current i in can be calculated, that is, the amplitude I in of the primary input current i in is obtained.

[0111] Step S230: Determine whether the primary input current is greater than or equal to a second preset value.

[0112] In one embodiment, the control device determines whether the amplitude I in of the primary input current i in is greater than or equal to the second preset value I in-set .

[0113] In another embodiment, step S230 may further include:

[0114] Step S231: Collect the secondary output current output from the secondary circuit of the secondary device to the controllable rectifier circuit.

[0115] Specifically, the secondary output current output from the secondary circuit of the secondary device to the controllable rectifier circuit, i e , can also be collected to obtain the amplitude I e of the secondary output current i e .

[0116] Step S232: Determine whether the secondary output current is greater than or equal to a third preset value;

[0117] Specifically, based on determining whether the amplitude I in of the primary input current i in is greater than or equal to the second preset value I in-set , the control device can also simultaneously determine whether the amplitude I e of the secondary output current i e is greater than or equal to the third preset value I e-set .

[0118] Step S240: If the primary input current is greater than or equal to the second preset value, control the secondary device to switch to the next impedance mode according to the current impedance mode of the secondary device and the preset switching sequence.

[0119] Specifically, the preset switching sequence is the capacitive impedance mode, inductive impedance mode, and resistive impedance mode arranged in sequence. Considering the heat, efficiency, and working life of the switching device operating mode, in the case where simultaneous zero-voltage / current turn-on and turn-off cannot be achieved, the better operating mode is zero-voltage turn-on, followed by zero-current turn-off, and the worst mode is hard turn-on and turn-off. Therefore, the optimal secondary-side impedance mode is the capacitive impedance mode, followed by the inductive impedance mode, and the worst is the resistive impedance mode, thus obtaining the preset switching sequence.

[0120] In one embodiment, if the primary-side input current i in has an amplitude I in greater than or equal to the second preset value I in-set , then control the secondary-side device to switch to the next impedance mode.

[0121] Further, step S240 may include:

[0122] Step S241: If the primary-side input current is greater than or equal to the second preset value, then according to the current impedance mode of the secondary-side device and the preset switching sequence, based on the zero-crossing point and amplitude of the waveform of the secondary-side output current output from the secondary-side circuit of the secondary-side device to the controllable rectifier circuit, phase-shift the secondary-side output voltage of the secondary-side device to control the impedance mode of the secondary-side device to switch to the next impedance mode.

[0123] Specifically, before phase-shifting the secondary-side output voltage of the secondary-side device through the zero-crossing point and amplitude of the waveform of the secondary-side output current to control the secondary-side device to switch to the next impedance mode, the waveform of the secondary-side output current output from the secondary-side circuit of the secondary-side device to the controllable rectifier circuit may also be collected first through a sampling circuit or sampling device.

[0124] When switching the impedance mode of the secondary-side device, if the current is the capacitive impedance mode, then when the primary-side input current is greater than or equal to the second preset value, control the secondary-side device to switch to the inductive impedance mode. Specifically, control switch tube S3 and switch tube S4 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 achieves zero-current turn-off but non-zero-voltage turn-on. At this time, the switching device can operate in the ZCS (zero-current switching) state. If the current is the inductive impedance mode, then when the primary-side input current is greater than or equal to the second preset value, control the secondary-side device to switch to the resistive impedance mode. Specifically, by controlling the on-time and off-time of switch tube S3 and switch tube S4, make the secondary-side output voltage u e and the secondary-side output current i e in the same phase, so that the imaginary part of the equivalent impedance R e of the secondary-side circuit is zero. At this time, the switching device operates in the hard-switching state.

[0125] It should be noted that step S241 corresponds to an implementation manner of step S230. Correspondingly, in another implementation manner of step S230, after step S232, step S240 may also have another implementation manner, that is, step S240 may further include:

[0126] Step S242: If the primary input current is greater than or equal to a second preset value, or the secondary output current is greater than or equal to a third preset value, then control the secondary device to switch to the next impedance mode according to the current impedance mode of the secondary device and the preset switching sequence.

[0127] Specifically, if the magnitude I in of the primary input current i in is greater than or equal to the second preset value I in-set , or the magnitude I e of the secondary output current i e is greater than or equal to the third preset value I e-set , then the secondary device can be controlled to switch to the next impedance mode. Among them, the method of controlling the switching to the next impedance mode is similar to that in the aforementioned step S241 and will not be elaborated here.

[0128] Step S250: Based on the impedance mode after the switching of the secondary device, control the secondary device to receive the energy transmitted by the primary device.

[0129] Specifically, based on the impedance mode after the switching of the secondary device, control the primary device to send energy to the secondary device, and control the secondary device to receive the energy transmitted by the primary device. That is, after switching to the current appropriate impedance mode, the system continues power transmission, returns to step S210, continues to obtain the real-time operating parameters of the system, and determines whether to switch the impedance mode.

[0130] Step S260: If the primary input current is less than the second preset value, then based on the current impedance mode of the secondary device, control the secondary device to receive the energy transmitted by the primary device.

[0131] In one implementation manner, if the magnitude I in of the primary input current i in is less than the second preset value I in-set , then based on the current impedance mode, return to step S210, continue to obtain the real-time operating parameters of the system, monitor whether the system meets the impedance mode switching conditions, perform impedance mode switching on the secondary device, and / or maintain the current state to perform wireless charging normally, that is, control the secondary device to receive the energy transmitted by the primary device, and control the controllable rectifier circuit to rectify the energy received by the secondary device and send it to the load R to charge the load R.

[0132] In another embodiment, if the primary-side input current i in has an amplitude I in less than a second preset value I in-set , and the secondary-side output current i e has an amplitude I e less than a third preset value I e-set , then based on the current impedance mode of the secondary-side device, step S210 can be returned to and / or the secondary-side device can be controlled to receive the energy transmitted by the primary-side device.

[0133] During the specific implementation process, after step S230, the method may further include:

[0134] Step S270: When the current impedance mode is a resistive impedance mode, if the primary-side input current is greater than or equal to the second preset value, then control the secondary-side device to stop receiving the energy transmitted by the primary-side device or receive the energy transmitted by the primary-side device in a low-power state.

[0135] In the resistive impedance mode, it is no longer possible to perform a resistive mode switch subsequently. However, if the primary-side input current at this time is greater than or equal to the second preset value, it indicates that the current system has been fully charged or there is no operating point in the system. Correspondingly, the control device can control the secondary-side device to stop receiving the energy transmitted by the primary-side device or receive the energy transmitted by the primary-side device in a low-power state.

[0136] Correspondingly, for another embodiment of step S230, after step S230, the method may further include:

[0137] When the current impedance mode is a resistive impedance mode, if the primary-side input current is greater than or equal to the second preset value, or the secondary-side output current is greater than or equal to the third preset value, the control device can control the secondary-side device to stop receiving the energy transmitted by the primary-side device or receive the energy transmitted by the primary-side device in a low-power state.

[0138] In specific implementation, it is also possible to stop the energy transmission between the primary-side device and the secondary-side device or transmit the energy in a low-power state when the current impedance mode is a capacitive impedance mode or an inductive impedance mode, based on the control instruction received by the control device or the user operation.

[0139] The secondary-side impedance mode control method provided in this embodiment calculates the primary input current output from the inverter circuit to the primary circuit by obtaining the secondary-side impedance angle; when it is determined that the primary input current is greater than or equal to the second preset value, the secondary-side device is controlled to switch to the next impedance mode according to the current impedance mode and the preset switching sequence; and based on the switched impedance mode, the secondary-side device is controlled to receive the energy transmitted by the primary-side device, so as to realize the real-time and automatic switching of the impedance mode of the secondary-side device. The present invention collects the system operating parameters in real time during the power transmission stage of the wireless charging system, automatically switches the impedance mode of the secondary-side device, realizes full-power output under different working conditions, effectively improves the power transmission ability of the electric vehicle wireless charging system when applied under different working conditions, and improves the control flexibility and power transmission efficiency of the system.

[0140] Embodiment 2

[0141] Based on the same inventive concept, referring to Figures 2 to 5 , the first embodiment of the wireless charging system of the present invention is proposed. The system may be a wireless charging system applied in the field of electric vehicles.

[0142] Next, with reference to the connection schematic diagram shown in Figure 2 , the wireless charging system provided in this embodiment will be described in detail. The system may include:

[0143] The primary-side device;

[0144] The secondary-side device;

[0145] The control device respectively connected to the primary-side device and the secondary-side device.

[0146] 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, which can be specifically set according to the actual situation.

[0147] Those skilled in the art can understand that Figure 2 the structure shown in

[0148] does not constitute a limitation to the wireless charging system of the present invention, and may include more or fewer components than shown in the figure, or combine some components, or have different component arrangements. Figure 3Schematic diagram of the hardware structure shown; the control device may include a processor and a memory, and a secondary-side impedance mode control program is stored in the memory. When the secondary-side impedance mode control program is executed by the processor, all or part of the steps of the secondary-side impedance mode control method of the present invention are implemented.

[0149] It can be understood that the 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 on the control device, and it may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0150] Among them, the communication bus is used to realize the connection and communication between these components.

[0151] 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.

[0152] 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.

[0153] The memory is used to store various types of data, which may include, for example, instructions of any application program or method in the control device, as well as data related to the application program. 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 (Static Random Access Memory, abbreviated as SRAM), random access memory (Random Access Memory, abbreviated as RAM), electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, abbreviated as EEPROM), erasable programmable read-only memory (Erasable Programmable Read-Only Memory, abbreviated as EPROM), programmable read-only memory (Programmable Read-Only Memory, abbreviated as PROM), read-only memory (Read-Only Memory, abbreviated as ROM), magnetic memory, flash memory, a magnetic disk or an optical disc. Optionally, the memory may also be a storage device independent of the processor.

[0154] The processor is used to call the secondary-side impedance mode control program stored in the memory and execute the secondary-side impedance mode control method as described above. The processor can be an Application Specific Integrated Circuit (ASIC), a Digital Signal Processor (DSP), a Digital Signal Processing Device (DSPD), a Programmable Logic Device (PLD), a Field Programmable Gate Array (FPGA), a controller, a microcontroller, a microprocessor, or other electronic components, and is used to execute all or part of the steps of each embodiment of the secondary-side impedance mode control method as described above.

[0155] Furthermore, as Figure 4 shown in the circuit connection schematic diagram; the secondary-side device includes a secondary-side circuit and a controllable rectifier circuit connected to each other, and the primary-side device includes an inverter circuit and a primary-side 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. The power supply DC is a DC power supply, and the load R can be a storage battery or a power execution component.

[0156] 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;

[0157] 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 controllable rectifier circuit.

[0158] Furthermore, as Figure 5Schematic diagram of the circuit connection shown; the controlled rectifier circuit includes four switching devices, namely diode D1 and diode D2, switch S3 and switch 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 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 S4. The gates of the switch S3 and the switch 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 S3 and the switch S4 are respectively connected to the other end of the load R. A capacitor C0 is also connected in parallel across the two ends of the load R, which can be used to store electrical energy.

[0159] 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 secondary side impedance mode control method of the present invention. For the sake of brevity of the specification, it will not be elaborated here.

[0160] Embodiment III

[0161] Based on the same inventive concept, this embodiment provides a computer-readable storage medium, such as flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory, etc.), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, magnetic disk, optical disc, 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 secondary side impedance mode control method of the present invention in each embodiment can be realized.

[0162] 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.

[0163] 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 description 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 secondary-side impedance modal control method, characterized in that Applied to a wireless charging system, the system includes a primary device and a secondary device, the primary device and the secondary device are electromagnetically inductively connected, the primary device includes an inverter circuit and a primary circuit connected to each other, and the method includes: Obtain the current impedance mode and the secondary impedance angle of the secondary device; According to the secondary impedance angle, obtain the primary input current output from the inverter circuit to the primary circuit in the primary device; Determine whether the primary input current is greater than or equal to a second preset value; If the primary input current is greater than or equal to the second preset value, control the secondary device to switch to the next impedance mode according to the current impedance mode of the secondary device and a preset switching sequence; wherein, the preset switching sequence is a capacitive impedance mode, an inductive impedance mode, and a resistive impedance mode arranged in sequence; Based on the impedance mode after the secondary device switches, control the secondary device to receive the energy transmitted by the primary device.

2. The secondary-side impedance mode control method according to claim 1, wherein After the step of determining whether the primary input current is greater than or equal to the second preset value, the method further includes: If the primary input current is less than the second preset value, control the secondary device to receive the energy transmitted by the primary device based on the current impedance mode of the secondary device.

3. The secondary-side impedance mode control method according to claim 1, wherein The secondary device includes a secondary circuit and a controllable rectifier circuit connected to each other; The step of obtaining the current impedance mode and the secondary impedance angle of the secondary device includes: During the energy transmission between the primary device and the secondary device, collect the primary coil current of the primary device and the secondary coil current of the secondary device; Determine whether the primary coil current reaches a first preset value; If the primary coil current reaches the first preset value, obtain the current impedance mode of the secondary device; According to the primary coil current and the secondary coil current, obtain the secondary impedance angle of the secondary device.

4. The secondary-side impedance mode control method according to claim 3, wherein 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, 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 ends of the primary coil Lp and 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, the other end of the capacitor Cs is respectively connected to one end of the capacitor C2 and one end of the inductor L2, and 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; The step of obtaining the secondary impedance angle of the secondary device according to the primary coil current and the secondary coil current includes: Detect the mutual inductance value; According to the mutual inductance value, the primary coil current, and the secondary coil current, use a second calculation formula to obtain the secondary impedance angle of the secondary device, and the second calculation formula is: 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; ω represents the system operating angular frequency; M represents the mutual inductance value; I p represents the amplitude of the primary side coil current i p ; I s represents the amplitude of the secondary side coil current i s .

5. The secondary side impedance mode control method according to claim 4, characterized in that The step of obtaining the primary input current output from the inverter circuit in the primary device to the primary circuit according to the secondary impedance angle includes: According to the secondary impedance angle, using a third calculation formula, obtain the primary input current output from the inverter circuit in the primary device to the primary circuit, and the third calculation formula is: wherein, i in represents the primary input current; Γ represents the rate of change of the inductance value L of the primary coil Lp p ; L1 represents the inductance value of the inductance L1; I p represents the amplitude of the primary coil current i p ; M represents the mutual inductance value; I s represents the amplitude of the secondary coil current i s ; β represents the secondary impedance angle; ω represents the system operating angular frequency; η VA represents the efficiency required by the secondary device; j is the imaginary part.

6. The secondary-side impedance mode control method according to claim 3, wherein The step of, if the primary input current is greater than or equal to a second preset value, controlling the secondary device to switch to the next impedance mode according to the current impedance mode of the secondary device and a preset switching sequence further includes: Collect the secondary output current output from the secondary circuit in the secondary device to the controlled rectifier circuit; Judge whether the secondary output current is greater than or equal to a third preset value; If the primary input current is greater than or equal to the second preset value, or the secondary output current is greater than or equal to the third preset value, control the secondary device to switch to the next impedance mode according to the current impedance mode of the secondary device and the preset switching sequence.

7. The secondary side impedance mode control method according to claim 3, wherein Before the step of controlling the secondary device to switch to the next impedance mode according to the current impedance mode of the secondary device and the preset switching sequence, the method further includes: Collect the waveform of the secondary output current output from the secondary circuit in the secondary device to the controlled rectifier circuit; The step of controlling the secondary device to switch to the next impedance mode includes: 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 switch to the next impedance mode.

8. The secondary-side impedance mode control method according to claim 1, wherein After the step of judging whether the primary input current is greater than or equal to the second preset value, the method further includes: When the current impedance mode is a resistive impedance mode, if the primary input current is greater than or equal to the second preset value, control the secondary device to stop receiving the energy transmitted by the primary device or receive the energy transmitted by the primary device in a low-power state.

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, and a secondary impedance mode control program is stored on the memory. When the secondary impedance mode control program is executed by the processor, it implements the secondary impedance mode control method according to any one of claims 1 to 8.

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, it implements the secondary impedance mode control method according to any one of claims 1 to 8.

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