Method and device for calculating maximum efficiency of wireless power transmission, equipment and storage medium

Abstract

This invention relates to a method, apparatus, device, and storage medium for calculating the maximum efficiency of wireless power transfer, belonging to the fields of wireless communication and new energy technology. The method includes: S1, for a simplified model of a phase-shifted full-bridge inverter, acquiring the DC-side input voltage and input current of the simplified model; S2, calculating the DC-side input impedance of the simplified model based on the DC-side input voltage and the input current, and calculating the current phase-shift angle of the simplified model based on the DC-side input impedance and a closed-loop iterative formula; S3, updating the current phase-shift angle until a dynamic response in the DC-side input impedance is triggered, and using the current phase-shift angle corresponding to the dynamic response as the final phase-shift angle. This invention first utilizes a simplified model that ignores minor losses to quickly estimate the phase-shift angle, and then uses local perturbation to lock in the true optimal final phase-shift angle, thereby overcoming the low tracking efficiency of traditional methods and achieving high-efficiency charging under load variations.

Description

Technical Field

[0001] This invention relates to the fields of wireless communication and new energy technology, and in particular to a method, apparatus, device and storage medium for calculating the maximum efficiency of wireless power transmission. Background Technology

[0002] With the widespread use of electrical energy and electronic devices, the drawbacks of traditional wired charging have become increasingly apparent in certain areas. For example, frequent plugging and unplugging of commonly used electronic devices leads to wear and tear on the interfaces, and major safety accidents caused by line wear are not uncommon. Wireless Power Transfer (WPT) technology, as an emerging energy access method, has come into the public eye due to its unique contactless advantages, solving some of the pain points of traditional wired charging. Especially in the field of high-power electric vehicle charging, some charging guns are heavy and difficult to align properly when plugging and unplugging, leading to frequent plugging and unplugging and equipment damage. Wired charging solutions are further limited in rainy or snowy weather. Therefore, wireless power transfer technology has received widespread attention and in-depth research in the 21st century.

[0003] Because the LCC-S type topology integrates the primary-side LCC resonant network and the secondary-side series S-compensation structure, the LCC resonant network enables constant current output from the transmitting coil, significantly reducing the switching stress on the inverter's switching devices. Combined with the secondary-side series compensation network, the LCC-S type wireless power transfer system achieves load-independent constant voltage output characteristics. Energy is transferred from the primary side to the secondary side via a high-frequency magnetic field, and after synchronous rectification and DC / DC conversion, provides stable and reliable power to the load, adapting to battery charging characteristics. Simultaneously, it decouples the LCC resonant network output from the load-side output, facilitating algorithmic control.

[0004] However, as a high-order strongly coupled nonlinear system, the LCC-S wireless power transmission system is quite sensitive to changes in load and coupling coefficient. Therefore, achieving maximum efficiency tracking (MET) under all operating conditions is a key area that needs in-depth research.

[0005] Most existing closed-loop maximum efficiency tracking methods rely on real-time communication between the primary and secondary sides, which increases the size and cost of the device and introduces latency in the wireless communication module. In contrast, the traditional perturbation observation method, which does not require communication between the primary and secondary sides, is essentially a gradient blind search strategy with a large number of redundant search steps to approach the optimal efficiency point. This addresses the blind search defect caused by the lack of an "estimation model" in existing traditional maximum efficiency tracking strategies. Summary of the Invention

[0006] In view of this, it is necessary to provide a method, apparatus, device and storage medium for calculating the maximum efficiency of wireless power transmission, so as to solve the problem of low search efficiency of traditional tracking strategies.

[0007] To address the aforementioned problems, this invention provides a method for calculating the maximum efficiency of wireless power transmission, applicable to LCC-S type wireless power transmission systems, comprising: S1, if an initialization command or a resistor change command is received, then for the simplified model of the phase-shifted full-bridge inverter in the LCC-S type wireless power transmission system, the DC side input voltage and input current of the simplified model are collected; S2, calculate the DC-side input impedance of the simplified model based on the DC-side input voltage and the input current, and calculate the current phase shift angle of the simplified model based on the DC-side input impedance and the closed-loop iterative formula; S3, update the current phase shift angle until it causes a dynamic response of the DC side input impedance, and take the current phase shift angle corresponding to the dynamic response as the final phase shift angle.

[0008] Furthermore, step S3 is followed by: S4. Using a phase-shifting perturbation optimization algorithm, the current phase-shifting angle is changed according to a preset angle until the operating efficiency of the LCC-S type wireless power transmission system is maximized, and the final current phase-shifting angle is used as the final phase-shifting angle.

[0009] Further, step S4 includes: S41, calculate the current input power corresponding to the current phase shift angle of the simplified model, add a preset angle to the current phase shift angle to obtain the next phase shift angle, and further calculate the next input power corresponding to the next phase shift angle of the simplified model; S42, if the next input power is less than the current input power, then the next phase shift angle is increased by the preset angle, and the current phase shift angle is increased by the preset angle. If the recalculated next input power is less than the recalculated current input power, this step is repeated until the recalculated next input power is not less than the recalculated current input power, and the current phase shift angle is taken as the final phase shift angle. S43, if the next input power is not less than the current input power, then the next phase shift angle is reduced by the preset angle, and the current phase shift angle is reduced by the preset angle. If the recalculated next input power is less than the recalculated current input power, this step is repeated until the recalculated next input power is not less than the recalculated current input power, and the current phase shift angle is taken as the final phase shift angle.

[0010] Furthermore, the preset angle satisfies the following condition: Calculate the input power ripple of the LCC-S type wireless power transmission system when it is fully loaded, and take twice the input power ripple as the minimum value of the preset angle; Define the maximum efficiency offset of the LCC-S wireless power transfer system. and restrictions Under the constraint of the maximum efficiency offset, the maximum phase shift angle perturbation step size of the LCC-S wireless power transmission system is taken as the maximum value of the preset angle.

[0011] Furthermore, in step S3, the operating efficiency of the LCC-S type wireless power transmission system is calculated using the following formula: ; in, This indicates the operating efficiency. The AC equivalent resistance of the equivalent load circuit corresponding to the LCC-S type wireless power transfer system is given. This represents the equivalent series resistance of the primary coil in the LCC-S type wireless power transfer system. This represents the equivalent series resistance of the secondary coil in the LCC-S type wireless power transfer system. Indicates the switching frequency. This indicates mutual inductance between coils.

[0012] Furthermore, the closed-loop iterative formula described in step S2 is as follows: ; in, Indicates the current phase shift angle, This represents the DC-side input impedance. This represents the total load of the simplified model.

[0013] Furthermore, step S3 is followed by: Detect whether the DC side input impedance has changed abruptly. If a change occurs, send the resistance change command.

[0014] The present invention also provides a wireless power transmission maximum efficiency calculation device, applicable to LCC-S type wireless power transmission system, comprising: The acquisition module is used to acquire the DC-side input voltage and input current of the simplified model of the phase-shifted full-bridge inverter in the LCC-S type wireless power transmission system if an initialization command or a resistance change command is received. The calculation module is used to calculate the DC-side input impedance of the simplified model based on the DC-side input voltage and the input current, and to calculate the current phase shift angle of the simplified model based on the DC-side input impedance and the closed-loop iterative formula. The response module is used to update the current phase shift angle until a dynamic response is caused by the DC side input impedance, and the current phase shift angle corresponding to the dynamic response is taken as the final phase shift angle.

[0015] The present invention also provides an electronic device, including a memory and a processor, wherein the memory is used to store programs or instructions, and the processor is used to execute the programs or instructions stored in the memory to implement the above-described method for calculating the maximum efficiency of wireless power transmission.

[0016] The present invention also provides a computer-readable storage medium for storing a computer-readable program or instruction, which, when executed by a processor, enables the above-described method for calculating the maximum efficiency of wireless power transmission.

[0017] The beneficial effects of this invention are: based on the maximum efficiency tracking strategy that combines impedance model estimation with fixed-step perturbation, the phase shift angle is first estimated quickly using a simplified model that ignores minor losses, and then the true optimal final phase shift angle is locked through local perturbation. This makes up for the low tracking efficiency of traditional methods and meets the requirement of high-efficiency charging under load changes. Attached Figure Description

[0018] Figure 1 A flowchart illustrating a method for calculating the maximum efficiency of wireless power transmission, provided as an embodiment of the present invention; Figure 2 A circuit diagram of an LCC-S type wireless power transfer system provided in an embodiment of the present invention; Figure 3 A simplified model of a phase-shifted full-bridge inverter provided in an embodiment of the present invention is shown in the diagram. Figure 4 for Figure 2 A schematic diagram of the process of converting a medium-load, four-switch Buck-Boost converter and a secondary-side synchronous rectifier bridge into an equivalent AC resistance. Figure 5 An equivalent circuit model diagram of an LCC-S type wireless power transfer system provided in an embodiment of the present invention; Figure 6 A flowchart illustrating a method for calculating the maximum efficiency of wireless power transmission, provided in an embodiment of the present invention; Figure 7 A simulated output voltage waveform diagram of the constant voltage charging stage of a battery, provided for an embodiment of the present invention; Figure 8A simulated phase-shift angle waveform diagram of the constant-voltage charging stage of a battery, provided for an embodiment of the present invention; Figure 9 This is a dual Y-axis line graph illustrating the mapping relationship between optimization iteration steps, efficiency, and phase shift angle provided in an embodiment of the present invention. Figure 10 This is a structural diagram of a wireless power transmission maximum efficiency calculation device provided in an embodiment of the present invention. Detailed Implementation

[0019] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0020] The traditional fixed-step perturbation-observation method involves setting an initial phase shift angle and performing a large-scale blind search with a fixed step size. Its drawback is that optimization speed and efficiency / accuracy cannot be simultaneously achieved. Although the variable-step perturbation-observation method improves upon the shortcomings of the traditional fixed-step optimization strategy to some extent, it is still essentially a gradient blind search strategy, resulting in a relatively large number of perturbations and a long transient time for LCC-S type wireless power transfer (WPT) systems. Therefore, finding a maximum efficiency tracking method for wireless power transfer based on a combination of model estimation and perturbation-observation for LCC-S topology is crucial.

[0021] This invention aims to address the problems of reduced transmission efficiency and blind searching in LCC-S wireless power transfer systems without primary-secondary communication due to changes in parameters such as load. Unlike traditional SS topologies, LCC-S topologies are widely used in wireless charging due to their high offset resistance, ease of achieving zero-voltage switching (ZVS) to improve efficiency, and load-independent output characteristics.

[0022] Figure 1 A flowchart illustrating a method for calculating the maximum efficiency of wireless power transmission, provided in an embodiment of the present invention, is available. This method is applicable to LCC-S type wireless power transmission systems, such as... Figure 1 As shown, the method includes: Among them, LCC-S is a compensation topology commonly used in magnetically coupled resonant wireless power transfer systems (MCR-WPT), and its name comes from its circuit composition: LCC: refers to a composite compensation network used in the transmitter, consisting of an inductor (L) and two capacitors (C). It is usually an "L-type + CC-type" structure, which is a combination of a series inductor and two parallel / series capacitors.

[0023] S: This refers to the use of a simple series compensation network at the receiving end, which is a capacitor connected in series with the receiving coil.

[0024] Figure 2 A circuit diagram of an LCC-S type wireless power transfer system provided for an embodiment of the present invention is shown below. Figure 2 As shown, the LCC-S type wireless power transfer system mainly consists of a DC input power supply. Phase-shifting full-bridge inverter Original edge LCC compensation network Loosely coupled transformer (i.e., magnetically coupled coil) Secondary S-compensation network Secondary-side synchronous rectifier bridge Filter capacitor Four-switch Buck-Boost converter and load constitute.

[0025] S1, if an initialization command or a resistor change command is received, then for the simplified model of the phase-shifted full-bridge inverter in the LCC-S type wireless power transmission system, the DC side input voltage and input current of the simplified model are collected; During implementation, if an initialization command or a resistance change command is received, the DC-side input voltage and input current of the simplified model are collected.

[0026] The initialization command is sent when the LCC-S type wireless power transmission system is first turned on.

[0027] Figure 3 A simplified model of a phase-shifted full-bridge inverter provided in an embodiment of the present invention is shown in the diagram. Figure 3 As shown, the DC-side input voltage U of this simplified model is collected. in and input current I in .

[0028] S2, calculate the DC-side input impedance of the simplified model based on the DC-side input voltage and the input current, and calculate the current phase shift angle of the simplified model based on the DC-side input impedance and the closed-loop iterative formula; In this embodiment of the invention, the DC side input voltage U is utilized. in and input current I in The simplified model yields the DC-side input impedance R. in Based on the DC-side input impedance and the closed-loop iterative formula, the current phase shift angle of the simplified model is calculated.

[0029] As one implementation method, to simplify modeling and analysis, the ESR of the compensation inductor and the losses of the switching devices, which have a relatively small impact on the efficiency of the LCC-S type wireless power transfer system, are ignored, and since the input voltage and input current of the synchronous rectifier bridge are basically in phase. Figure 4 for Figure 2 A schematic diagram illustrating the process of converting a medium-load, four-switch Buck-Boost converter and a secondary-side synchronous rectifier bridge into an equivalent AC resistance. Figure 5 The present invention provides an LCC-S equivalent circuit model diagram of an LCC-S type wireless power transmission system.

[0030] Based on the above LCC-S equivalent circuit model, the loop impedance equation is established according to the loop current method, Kirchhoff's laws, and the resonance condition of the LCC-S topology. The solution is then obtained. Figure 5 The currents I1, I2 and I3 in each loop are used, and the input-output power ratio of each loop current is introduced into the formula (1). The relationship between the operating efficiency of the LCC-S type wireless power transmission system and the AC equivalent resistance can be derived.

[0031] (1) in, This indicates the operating efficiency. express Figure 5 The second current in the LCC-S equivalent circuit model. express Figure 5 The third current in the LCC-S equivalent circuit model. for Figure 4 The AC equivalent resistance of an intermediate load circuit. This represents the ESR of the coil in the primary-side LCC compensation network. This represents the ESR of the coil in the secondary compensation network. Indicates the switching frequency. This indicates mutual inductance between coils.

[0032] For formula (1) By taking the derivative, the sign of the derivative can be used to determine the performance of the LCC-S type wireless power transfer system. When the value is positive, there is one and only one maximum point. This maximizes the operating efficiency of the LCC-S wireless power transmission system, and the optimal load is shown in formula (2). From formula (2), it can be seen that the optimal load of the LCC-S wireless power transmission system is determined by the circuit parameters.

[0033] (2) For example Figure 2 The LCC-S type wireless power transfer system shown has its power ratings marked on [the diagram / table]. Figure 2In this system, the phase-shifted full-bridge inverter controls the input power and input voltage of the WPT system by adjusting the phase shift angle. The four-switch Buck-Boost converter employs a dual-closed-loop PI control strategy to regulate the load output voltage or current in a closed loop, based on the constant current (CC) or constant voltage (CV) charging characteristics of the load, thereby achieving stable output on the load side.

[0034] In this WPT system, a four-switch Buck-Boost converter controlled by dual closed-loop PI switches stabilizes the output voltage or current on the load side (determined by constant current charging or constant voltage charging of the load). When the phase shift angle is adjusted, the voltage / current gain of the phase-shifted full-bridge inverter changes. After passing through the primary-side LCC compensation network and rectification stage with constant voltage / current gain, the duty cycle D of the four-switch Buck-Boost converter is changed to keep the output voltage / current constant. , The relationship between the duty cycle D of the four-switch Buck-Boost converter and the phase shift angle is shown in formula (3). When the output is stabilized by the four-switch Buck-Boost converter, there is a one-to-one mapping relationship between the phase shift angle of the phase-shifted full-bridge inverter and the AC equivalent resistance. Therefore, changing the phase shift angle is essentially changing the equivalent AC impedance. .

[0035] The maximum efficiency tracking method of this invention is essentially to find the point that allows the equivalent AC resistance to be tracked. equal This maximizes the operating efficiency of the LCC-S wireless power transmission system.

[0036] (3) assumed The LCC-S type wireless power transfer system operates at its maximum efficiency point and resonant point. Its input impedance exhibits purely resistive behavior. A simplified model of the DC voltage input, the phase-shifted full-bridge inverter, and the LCC-S input impedance is established as follows: Figure 3 As shown, the electricity levels are labeled in the diagram.

[0037] use Figure 3 The LCC-S equivalent circuit model can be obtained and The relationship is shown in formula (4).

[0038] (4) right Figure 3 The simplified model of the phase-shifted full-bridge inverter presented uses fundamental frequency analysis and ignores the phase-shifted full-bridge inverter. The tiny power loss makes it an ideal switching device. Based on the gain of the phase-shifted full-bridge inverter and the conservation of its input and output power, the equation shown in formula (5) can be obtained.

[0039] (5) From formula (5), we can obtain and phase shift angle The relationship between them is shown in formula (6).

[0040] (6) Based on formula (6), an iterative convergence control strategy is designed to sample the DC side of the LCC-S type wireless power transmission system in real time. and Real-time calculation of the DC input impedance of the current system Calculated and updated using formula (6) , The update will change the gain of the phase-shifted full-bridge inverter, which will eventually cause... The dynamic response forms a closed-loop iterative process of sampling, calculation, adjustment, and resampling, ultimately causing the phase shift angle to converge rapidly to the estimated optimal phase shift angle. The current phase shift angle is calculated using formula (6).

[0041] S3, update the current phase shift angle until a dynamic response is caused to the DC side input impedance, and take the current phase shift angle corresponding to the dynamic response as the final phase shift angle.

[0042] Continuously update the current phase shift angle until it causes Figure 3 The dynamic response of the DC-side input impedance is calculated, and the current phase shift angle under the dynamic response condition is taken as the final phase shift angle. .

[0043] The embodiments of the present invention are based on a maximum efficiency tracking strategy that combines impedance model estimation with fixed-step perturbation. First, a simplified model that ignores minor losses is used to quickly estimate the phase shift angle. Then, the true optimal final phase shift angle is locked through local perturbation. This makes up for the low tracking efficiency of traditional methods and meets the requirement of high-efficiency charging under load changes.

[0044] In estimating the current phase shift angle, the closed-loop iterative formula ignores some losses that have a small impact on the result, such as the ESR of the LCC-S compensation element and the power loss of the switching transistors of the phase-shifted full-bridge inverter. Therefore, the mathematical model of the estimated final phase shift angle has a slight deviation from the actual optimal phase shift angle.

[0045] Therefore, in some embodiments, step S3 is followed by: S4. Using a phase-shifting perturbation optimization algorithm, the current phase-shifting angle is changed according to a preset angle until the operating efficiency of the LCC-S type wireless power transmission system is maximized, and the final current phase-shifting angle is used as the final phase-shifting angle.

[0046] However, because the power loss caused by the ESR of the compensation components in the system, as well as the power loss of the switching devices in the phase-shifted full-bridge inverter, synchronous rectifier bridge, and four-switch Buck-Boost converter, are ignored in the above modeling process, the estimated final phase shift angle based on this model is... At the actual optimal phase shift angle Since the area is nearby, a phase-shifting perturbation optimization algorithm needs to be introduced.

[0047] In the phase-shifting disturbance optimization algorithm, since the output voltage or output current of the four-switch Buck-Boost converter with dual closed-loop PI control remains constant across the load, the output power remains constant under stable load conditions. Changing the phase shift angle in the phase-shifting full-bridge inverter can change the system's input power. When the system's input power reaches its minimum, the system's efficiency reaches its maximum.

[0048] Based on this, the optimization process involves real-time detection of the DC-side input voltage. With input current Calculate the input power of the LCC-S type wireless power transfer system, change the phase shift angle, compare the input power with the previous input power, and control the phase shift angle to gradually approach the optimal phase shift angle. After reaching the set minimum input power criterion, the phase shift angle is stabilized, enabling the LCC-S type wireless power transmission system to operate stably at the point of maximum efficiency.

[0049] In one implementation, step S4 includes: S41, calculate the current input power corresponding to the current phase shift angle of the simplified model, add a preset angle to the current phase shift angle to obtain the next phase shift angle, and further calculate the next input power corresponding to the next phase shift angle of the simplified model; S42, if the next input power is less than the current input power, then the next phase shift angle is increased by the preset angle, and the current phase shift angle is increased by the preset angle. If the recalculated next input power is less than the recalculated current input power, this step is repeated until the recalculated next input power is not less than the recalculated current input power, and the current phase shift angle is taken as the final phase shift angle. S43, if the next input power is not less than the current input power, then the next phase shift angle is reduced by the preset angle, and the current phase shift angle is reduced by the preset angle. If the recalculated next input power is less than the recalculated current input power, this step is repeated until the recalculated next input power is not less than the recalculated current input power, and the current phase shift angle is taken as the final phase shift angle.

[0050] Figure 6 A flowchart illustrating a method for calculating the maximum efficiency of wireless power transmission provided in an embodiment of the present invention is shown below. Figure 6 As shown, based on the current phase shift angle calculated in the previous steps, the current phase shift angle is further optimized. First, the current input power corresponding to the current phase shift angle is calculated, and then the current phase shift angle is increased by a preset angle to obtain the next phase shift angle. Similarly, the next input power corresponding to the next phase shift angle is calculated.

[0051] The next input power is compared with the current input power. If the next input power is less than the current input power, the next phase shift angle is increased by a preset angle, and the current phase shift angle is increased by a preset angle. The recalculated next input power is compared with the recalculated current input power. If the recalculated next input power is less than the recalculated current input power, the step is repeated until the recalculated next input power is not less than the recalculated current input power. The current phase shift angle is then used as the final phase shift angle.

[0052] The next input power is compared with the current input power. If the next input power is not less than the current input power, the next phase shift angle is reduced by a preset angle, and the current phase shift angle is reduced by a preset angle. The recalculated next input power is compared with the recalculated current input power. If the recalculated next input power is not less than the recalculated current input power, the step is repeated until the recalculated next input power is not less than the recalculated current input power. The current phase shift angle is then used as the final phase shift angle.

[0053] In the above embodiments, the preset angle satisfies the following conditions: Calculate the input power ripple of the LCC-S type wireless power transmission system when it is fully loaded, and take twice the input power ripple as the minimum value of the preset angle; Define the maximum efficiency offset of the LCC-S wireless power transfer system. and restrictions Under the constraint of the maximum efficiency offset, the maximum phase shift angle perturbation step size of the LCC-S wireless power transmission system is taken as the maximum value of the preset angle.

[0054] The phase-shifting angle perturbation step size (i.e., the preset angle) in the phase-shifting perturbation optimization algorithm. The selection is based on the observability and steady-state tracking accuracy of the LCC-S wireless power transfer system. Since the phase-shifted full-bridge inverter inevitably generates input power ripple during operation... Based on the observability of the LCC-S wireless power transfer system, if the perturbation step size Caused input power change This could lead to the algorithm misjudging the trend of changes in input power, thus affecting the perturbation step size of the phase shift angle. The lower bound is restricted, and in this invention, it is... The lower bound is set to the input power ripple under worst-case conditions (when the system is under full load). This is twice the lower bound, leaving some margin. In practice, simple offline tests can be conducted to determine this lower bound. .

[0055] Steady-state tracking accuracy and perturbation step size based on LCC-S wireless power transfer system The upper bound is limited by the engineering-acceptable range of efficiency deviation. The efficiency curve of the LCC-S wireless power transfer system is relatively flat near the maximum efficiency point; the maximum efficiency deviation is defined as... ,limit Under this maximum efficiency offset constraint, the maximum perturbation step size allowed by the LCC-S wireless power transfer system is the upper bound of the perturbation step size. Within this upper limit of the perturbation step size, the operating efficiency of the LCC-S wireless power transfer system can be maintained at over 99.5% of the theoretical optimum, meeting the steady-state tracking accuracy requirements for engineering applications.

[0056] Based on the above two points, the phase shift angle perturbation step size can be obtained. The upper realm and the lower realm Within this range, a suitable phase shift angle disturbance step size can be selected. This can avoid misjudging the power change trend caused by a single phase shift disturbance, and ensure that the steady-state efficiency is within the allowable error range of engineering.

[0057] Real-time detection after a single maximum efficiency tracking optimization is completed. If a mutation occurs, restart the maximum efficiency tracking algorithm and repeat the above process until it stabilizes at the maximum efficiency point again.

[0058] To verify the effectiveness of the embodiments of the present invention, specific simulation experiments are used to provide a more detailed explanation of the steps and effects of the present invention. Figure 7 A simulated output voltage waveform diagram of the constant voltage charging stage of a battery, as provided in an embodiment of the present invention, is shown below. Figure 7As shown, the constant voltage charging stage of battery charging is used as an example to verify the present invention and the traditional method. According to the parameters of the LCC-S wireless power transfer system shown in Table 1 and the resonant network parameters shown in Table 2, the circuit parameters are set to build an LCC-S wireless power transfer simulation platform with a rated power of 600W.

[0059] Table 1

[0060] Table 2

[0061] like Figure 7 As shown, the output voltage quickly stabilizes at 100V after startup. The voltage change during phase angle changes is small and the adjustment speed is fast. The voltage overshoot is only slightly large during startup and half-load switching, but it is only about 5V. This indicates that the LCC-S wireless power transfer system can ensure stable power quality at the output end and meet the requirements of battery CV charging. During the CC charging stage, only the four-switch Buck-Boost control object needs to be switched.

[0062] Figure 8 A simulated phase-shift angle waveform diagram of the constant-voltage charging stage of a battery, as provided in an embodiment of the present invention, is shown below. Figure 8 As shown, the LCC-S type wireless power transfer system starts with an initial phase shift angle of 140°. The use of a large phase shift angle for startup is to suppress the voltage and current overshoot generated in the resonant circuit at the moment of startup, avoid damage to the components or core saturation, and thus ensure the safe and reliable operation of the hardware system.

[0063] Within the time interval 0~t1, the LCC-S type wireless power transfer system completes the soft start and model estimation of the optimal phase shift angle. It adopts a ramp transition to reduce the voltage and current surges of the devices, thereby stabilizing the output power and reducing the adjustment time.

[0064] During the time interval t1 to t2, the LCC-S wireless power transmission system completes the disturbance optimization process. At time t2, the stable phase shift angle remains unchanged. At time t3, the LCC-S wireless power transmission system simulates load shedding, but at this time, the phase shift angle remains stable. If load shedding and phase shift angle change occur simultaneously at this time, a large overshoot will occur, and the output power will be extremely unstable. After the system stabilizes, the optimal phase shift angle is estimated and subsequent disturbance steps are performed.

[0065] Figure 9 This is a dual Y-axis line graph illustrating the mapping relationship between optimization iteration steps, efficiency, and phase shift angle provided in an embodiment of the present invention, as shown below. Figure 9As shown, in the initial state, the LCC-S wireless power transmission system is in a preset large phase shift angle state, with an efficiency of only 61.1%. Under this condition, the LCC-S wireless power transmission system mainly meets the requirements for safe start-up, but is not in the high-efficiency operating range, and the LCC-S wireless power transmission system has a large loss.

[0066] Subsequently, the phase shift angle was corrected for the first time based on the model estimation results, and the efficiency of the LCC-S wireless power transfer system rapidly increased to 92.7%, indicating that the model estimation results can enable the system operating point to quickly approach the high-efficiency region, thereby reducing the search range and number of search steps required for subsequent disturbance correction.

[0067] In subsequent steps, the algorithm continues to perform perturbation corrections near the initial approximation point obtained from the model estimation. When the phase shift angle is adjusted to 58.6°, the system efficiency decreases slightly, triggering the direction correction mechanism. The algorithm then switches to downward perturbation. Near step 4, the system reaches its optimal efficiency point. Further reduction of the phase shift angle detects another decrease in efficiency, thus determining the current vicinity as the optimal phase shift angle interval. Finally, the optimal efficiency point is locked, allowing the system to enter a stable operating state.

[0068] Because the efficiency curve of the LCC-S type wireless power transfer system exhibits a typical "flat" characteristic near the optimal efficiency point, disturbances near the optimal phase shift angle have little impact on efficiency during simulation. This also indicates that the optimization trajectory has been accurately located near the optimal phase shift angle, ensuring both maximum efficiency and the robustness of the control algorithm in steady state.

[0069] The hybrid algorithm for wireless power transfer maximum efficiency tracking based on model estimation and fixed-step perturbation described in this invention has the following advantages: (1) Fast optimization speed: By introducing a model prediction mechanism based on FHA modeling and analysis method, the system can realize the jump from low efficiency region to high efficiency region, avoiding the long search process of traditional P&O algorithm in blind search, and greatly reducing the optimization time of the system.

[0070] (2) It retains the advantage of not requiring communication between the primary and secondary sides, and has the advantages of low cost, simple structure and stability in some scenarios.

[0071] (3) By designing a reasonable step size and convergence criteria, the optimization oscillation near the optimal efficiency point can be effectively solved, and the oscillation at the optimal point can be avoided multiple times.

[0072] (4) This invention has the ability to automatically identify interference and correct the optimization direction by monitoring the changes in input power in real time. Even under complex operating conditions such as sudden load changes or coupling coefficient drift, it can still quickly re-lock the optimal efficiency point.

[0073] (5) The final simulation efficiency can reach 93.2%. By providing a rough initial position through the model and providing precise adjustment through the disturbance observation link, a balance between optimization speed and steady-state accuracy is achieved.

[0074] Figure 10 This invention provides a structural diagram of a wireless power transfer maximum efficiency calculation device, applicable to LCC-S type wireless power transfer systems, such as... Figure 10 As shown, the device includes: The acquisition module 10A is used to acquire the DC side input voltage and input current of the simplified model of the phase-shifted full-bridge inverter in the LCC-S type wireless power transmission system if an initialization command or a resistance change command is received. The calculation module 10B is used to calculate the DC-side input impedance of the simplified model based on the DC-side input voltage and the input current, and to calculate the current phase shift angle of the simplified model based on the DC-side input impedance and the closed-loop iterative formula. The response module 10C is used to update the current phase shift angle until a dynamic response is caused by the DC side input impedance, and to take the current phase shift angle corresponding to the dynamic response as the final phase shift angle.

[0075] This embodiment is a device embodiment corresponding to the above method embodiment. Its specific implementation process is the same as that of the above method embodiment. For details, please refer to the above method embodiment. This device embodiment will not be described again here.

[0076] In one embodiment, the present invention also provides an electronic device. The electronic device includes a memory and a processor. In some embodiments, the memory may be an internal storage unit of the electronic device, such as a hard disk or RAM. In other embodiments, the memory may be an external storage device of the electronic device, such as a plug-in hard disk, smart media card (SMC), secure digital card (SD), flash card, etc.

[0077] Furthermore, the memory can include both internal storage units and external storage devices of the electronic device, and the memory is used to install the application software and various types of data of the electronic device.

[0078] In some embodiments, the processor may be a single server or a group of servers. Servers may be centralized or distributed. In some embodiments, the processor may be local or remote. In some embodiments, the processor may be implemented on a cloud platform. In some embodiments, the cloud platform may include a private cloud, public cloud, hybrid cloud, community cloud, distributed cloud, internal cloud, multi-cloud, or any combination thereof.

[0079] Furthermore, when the processor executes the wireless power transfer maximum efficiency calculation program stored in memory, the following steps can be performed: S1, if an initialization command or a resistor change command is received, then for the simplified model of the phase-shifted full-bridge inverter in the LCC-S type wireless power transmission system, the DC side input voltage and input current of the simplified model are collected; S2, calculate the DC-side input impedance of the simplified model based on the DC-side input voltage and the input current, and calculate the current phase shift angle of the simplified model based on the DC-side input impedance and the closed-loop iterative formula; S3, update the current phase shift angle until it causes a dynamic response of the DC side input impedance, and take the current phase shift angle corresponding to the dynamic response as the final phase shift angle.

[0080] It should be understood that when the processor executes the program for calculating the maximum efficiency of wireless power transfer in memory, in addition to the functions mentioned above, it can also perform other functions, as detailed in the description of the corresponding method embodiments above.

[0081] Accordingly, embodiments of the present invention also provide a computer storage medium storing a computer program, which, when executed by a processor, implements the steps of the wireless power transmission maximum efficiency calculation method described in the above embodiments. Alternatively, when executed by a processor, the computer program implements the functions of each module / unit in the above embodiment of the wireless power transmission maximum efficiency calculation device.

[0082] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0083] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for calculating the maximum efficiency of wireless power transmission, applicable to LCC-S type wireless power transmission systems, characterized in that, include: S1, if an initialization command or a resistor change command is received, then for the simplified model of the phase-shifted full-bridge inverter in the LCC-S type wireless power transmission system, the DC side input voltage and input current of the simplified model are collected; S2, calculate the DC-side input impedance of the simplified model based on the DC-side input voltage and the input current, and calculate the current phase shift angle of the simplified model based on the DC-side input impedance and the closed-loop iterative formula; S3, update the current phase shift angle until a dynamic response is caused to the DC side input impedance, and take the current phase shift angle corresponding to the dynamic response as the final phase shift angle.

2. The method for calculating the maximum efficiency of wireless power transmission according to claim 1, characterized in that, Step S3 is followed by: S4. Using a phase-shifting perturbation optimization algorithm, the current phase-shifting angle is changed according to a preset angle until the operating efficiency of the LCC-S type wireless power transmission system is maximized, and the final current phase-shifting angle is used as the final phase-shifting angle.

3. The method for calculating the maximum efficiency of wireless power transmission according to claim 2, characterized in that, Step S4 includes: S41, calculate the current input power corresponding to the current phase shift angle of the simplified model, add a preset angle to the current phase shift angle to obtain the next phase shift angle, and further calculate the next input power corresponding to the next phase shift angle of the simplified model; S42, if the next input power is less than the current input power, then the next phase shift angle is increased by the preset angle, and the current phase shift angle is increased by the preset angle. If the recalculated next input power is less than the recalculated current input power, this step is repeated until the recalculated next input power is not less than the recalculated current input power, and the current phase shift angle is taken as the final phase shift angle. S43, if the next input power is not less than the current input power, then the next phase shift angle is reduced by the preset angle, and the current phase shift angle is reduced by the preset angle. If the recalculated next input power is less than the recalculated current input power, this step is repeated until the recalculated next input power is not less than the recalculated current input power, and the current phase shift angle is taken as the final phase shift angle.

4. The method for calculating the maximum efficiency of wireless power transmission according to claim 3, characterized in that, The preset angle satisfies the following conditions: Calculate the input power ripple of the LCC-S type wireless power transmission system when it is fully loaded, and take twice the input power ripple as the minimum value of the preset angle; Define the maximum efficiency offset of the LCC-S wireless power transfer system. and restrictions Under the constraint of the maximum efficiency offset, the maximum phase shift angle perturbation step size of the LCC-S wireless power transmission system is taken as the maximum value of the preset angle.

5. The method for calculating the maximum efficiency of wireless power transmission according to claim 2, characterized in that, In step S3, the operating efficiency of the LCC-S type wireless power transmission system is calculated using the following formula: ； in, This indicates the operating efficiency. The AC equivalent resistance of the equivalent load circuit corresponding to the LCC-S type wireless power transfer system is given. This represents the equivalent series resistance of the coil in the primary-side LCC compensation network of the LCC-S type wireless power transmission system. This represents the equivalent series resistance of the coil in the secondary compensation network of the LCC-S type wireless power transmission system. Indicates the switching frequency. This indicates mutual inductance between coils.

6. The method for calculating the maximum efficiency of wireless power transmission according to claim 1, characterized in that, The closed-loop iterative formula mentioned in step S2 is as follows: ； in, Indicates the current phase shift angle, This represents the DC-side input impedance. This represents the total load of the simplified model.

7. The method for calculating the maximum efficiency of wireless power transmission according to any one of claims 2 to 6, characterized in that, Step S3 is followed by: Detect whether the DC side input impedance has changed abruptly. If a change occurs, send the resistance change command.

8. A wireless power transmission maximum efficiency calculation device, applicable to LCC-S type wireless power transmission system, characterized in that, include: The acquisition module is used to acquire the DC-side input voltage and input current of the simplified model of the phase-shifted full-bridge inverter in the LCC-S type wireless power transmission system if an initialization command or a resistance change command is received. The calculation module is used to calculate the DC-side input impedance of the simplified model based on the DC-side input voltage and the input current, and to calculate the current phase shift angle of the simplified model based on the DC-side input impedance and the closed-loop iterative formula. The response module is used to update the current phase shift angle until a dynamic response is caused by the DC side input impedance, and the current phase shift angle corresponding to the dynamic response is taken as the final phase shift angle.

9. An electronic device, characterized in that, The method includes a memory and a processor, wherein the memory is used to store programs or instructions, and the processor is used to execute the programs or instructions stored in the memory to implement the wireless power transmission maximum efficiency calculation method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, Used to store computer-readable programs or instructions, which, when executed by a processor, enable the calculation method for maximum efficiency of wireless power transmission as described in any one of claims 1 to 7.

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