Electric vehicle low-speed dynamic wireless charging device based on magnetic coupling isolation transformer

Abstract

The invention discloses an electric vehicle low-speed dynamic wireless charging device based on a magnetic coupling isolation transformer, solves the problem that an existing low-power electric vehicle wireless charging test platform is insufficient in low-speed dynamic simulation, control verification and accurate measurement, and belongs to the technical field of electric vehicle charging. The system comprises a transmitting end, a linear guide rail platform, a receiving end, a measuring system, a lower computer controller (based on a DSP chip) and an upper computer real-time simulation control unit (adopting an RT Box platform), the receiving end is arranged in a sliding rail of the linear guide rail platform; the measuring system is used for measuring the current and voltage of the transmitting coil and the power and voltage of the receiving end load; the upper computer real-time simulation control unit operates a control algorithm according to the measured power, current and voltage to obtain a phase shift reference, a power track or a voltage track, and sends the phase shift reference, the power track or the voltage track to the lower computer controller; and the lower computer controller is used for performing power driving on the transmitting end according to the phase shift reference, the power track or the voltage track.

Description

Technical Field

[0001] This application relates to a low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer, belonging to the field of electric vehicle charging technology. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the number of electric vehicles on the road continues to grow, and the convenience, safety, and adaptability of their energy replenishment methods have attracted widespread attention. Traditional wired charging requires manual plugging and unplugging of the charging gun, which suffers from problems such as interface wear, cumbersome operation, and insulation performance being affected by the environment. Especially in harsh conditions such as rain, snow, high humidity, or low temperature, there is a risk of electric shock and equipment corrosion. Wireless charging technology utilizes the principle of magnetic coupling to achieve non-contact energy transfer between the transmitter and receiver, offering advantages such as safety, convenience, and a high degree of automation, and has become an important development direction for electric vehicle charging technology.

[0003] Currently, most wireless charging systems for electric vehicles are based on magnetically coupled isolation transformer structures, with compensation networks at both the transmitting and receiving ends to improve energy transmission efficiency. Existing technologies are generally suitable for static charging conditions, where the vehicle is completely stationary and the transmitting and receiving coils are accurately aligned. Under these conditions, the magnetic coupling coefficient of the system is relatively stable, and power transmission efficiency and soft-switching conditions are easily maintained. However, in low-speed dynamic charging scenarios, such as when the vehicle slowly enters the charging area, passes through a specific charging section at low speed, or continuously adjusts its position during parking, the relative position, lateral offset, and air gap distance between the transmitting and receiving ends constantly change, causing fluctuations in the magnetic coupling coefficient. Changes in the coupling coefficient can lead to unstable output power, soft-switching failure, increased current stress, and decreased system efficiency. In severe cases, it may trigger protection actions, causing the system to shut down.

[0004] Wireless charging technology utilizes magnetically coupled isolation transformers to achieve contactless energy transfer in space. It boasts advantages such as simple structure, safe operation, and no mechanical contact required, making it a promising technology for electric vehicle energy replenishment. Currently, research on wireless charging for electric vehicles largely focuses on high-power operational scenarios. However, conducting experiments directly on high-power systems during research processes such as control strategy verification, system parameter identification, and compensation topology optimization presents challenges including high safety risks, high equipment costs, and inconvenient adjustments.

[0005] To reduce experimental risks and improve R&D efficiency, researchers typically build low-power wireless charging test platforms in the laboratory to simulate the static or low-speed dynamic charging process of electric vehicles and verify different control algorithms, modulation strategies, and compensation structures. These low-power platforms generally consist of a transmitter power converter, a receiver power converter, a magnetically coupled isolation transformer, a compensation network, and a measurement and control system. By reducing the power level and operating voltage, system characteristic testing, control parameter optimization, and algorithm iteration can be achieved while ensuring operational safety.

[0006] Existing low-power wireless charging test platforms still have shortcomings in low-speed dynamic simulation and accurate measurement:

[0007] (1) The coil relative position is adjustable and the structure is simple, making it difficult to simulate the combined working conditions of multiple factors such as vehicle lateral offset and air gap change;

[0008] (2) The control and power regulation functions are simple, making it difficult to quickly switch and verify different modulation methods, compensation parameters and control algorithms;

[0009] (3) The lack of standardized high-voltage differential measurement interface and current sampling channel leads to insufficient waveform acquisition accuracy and affects the reliability of experimental data;

[0010] (4) The system protection and human-computer interaction functions are not perfect, which is not conducive to safe use in multi-user scenarios such as teaching and scientific research.

[0011] Therefore, there is an urgent need for a low-power test platform for wireless charging research of electric vehicles, which can simulate the low-speed dynamic charging process under low power and safe and controllable conditions, and has flexible control and measurement functions to meet the needs of algorithm verification and system performance evaluation in laboratory environment. Summary of the Invention

[0012] To address the shortcomings of existing low-power electric vehicle wireless charging test platforms in low-speed dynamic simulation, control verification, and accurate measurement, this application provides a low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer.

[0013] This application discloses a low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer, comprising a transmitter, a linear guide rail platform, a receiver, a measurement system, and a control terminal;

[0014] The control unit includes a lower-level controller and an upper-level real-time simulation control unit; the lower-level controller is implemented based on a DSP chip, and the upper-level real-time simulation control unit is implemented using the RT Box platform.

[0015] The linear guide platform includes a fixed support plate and a sliding guide rail;

[0016] The receiver is fixed in the slide rail of the linear guide platform, allowing the receiver to move continuously in the horizontal or vertical direction.

[0017] The transmitting coil at the transmitting end is mounted on a fixed support plate of the linear guide rail platform;

[0018] The measurement system is used to measure the current and voltage of the transmitting coil and send them to the host computer real-time simulation control unit. It is also used to measure the power and voltage of the receiving load and send them to the host computer real-time simulation control unit.

[0019] The host computer real-time simulation control unit is used to run control algorithms based on the measured power, current and voltage to obtain phase shift reference, power trajectory or voltage trajectory, and send it to the lower computer controller;

[0020] The lower-level controller is used to drive the transmitter to perform phase-shifted PWM based on the phase-shifting reference, power trajectory, or voltage trajectory.

[0021] As a preferred method, the host computer real-time simulation control unit obtains the power trajectory or voltage trajectory, including:

[0022] The coupling coefficient between the transmitter and receiver is obtained. When the coupling coefficient fluctuates, or the power and voltage of the load change abruptly, the trajectory of the transmitted power is generated by minimizing the objective function value of the transmitted power between the transmitter coil and the receiver coil, or the trajectory of the battery terminal voltage is generated by minimizing the objective function value of the battery terminal voltage, so as to achieve tracking error and dynamic smoothing.

[0023] The objective function for power transfer between the transmitting and receiving coils is:

[0024]

[0025] in, For the corresponding objective function value, This is a smoothing factor used to balance tracking error and dynamic smoothness. This indicates the power transferred between the transmitting and receiving coils. The expected power representing the transmission power. , This represents the time integration constant corresponding to the smoothing factor;

[0026] The objective function for the battery terminal voltage is:

[0027]

[0028] in, For the corresponding objective function value, Indicates the battery terminal voltage. This represents the expected value of the battery terminal voltage.

[0029] As a preferred option, the coupling coefficient for:

[0030]

[0031] in, This indicates the lateral offset between the transmitting and receiving coils. This indicates the change in the air gap between the transmitting and receiving coils. The maximum coupling coefficient during alignment. These are the lateral offset and air gap attenuation coefficients, respectively, obtained through experimental calibration.

[0032] Preferably, the host computer real-time simulation control unit is also used to identify parameters in the control algorithm online, including mutual inductance. Leakage and equivalent load ;

[0033] Online identification methods include:

[0034] Based on the equivalent coil model, parameter inversion is performed on the voltage and current at the sampling transmitter and receiver to obtain the mutual inductance. Equivalent leakage inductance and equivalent load Online estimates;

[0035] The equivalent model of the coil is:

[0036]

[0037] Indicates the self-inductance of the transmitting end. Indicates the receiver's self-inductance. Indicates the transmitter voltage. Receiver voltage, Indicates the transmitter current. This indicates the current at the receiving end.

[0038] As a preferred option, different relative permeabilities are also included. By using ground materials with varying dielectric properties and placing them above the transmitter, the effects of different ground materials on the coupling coefficient and transmission efficiency of the wireless charging system can be simulated.

[0039] Preferably, the receiving end includes a receiving coil, a receiving compensation network, a rectifier module, and an electronic load connected in sequence;

[0040] The transmitting end includes a transmitting coil, a transmitting compensation network, an inverter module, and a DC power supply connected in sequence; wherein, the lower-level controller controls the inverter module to realize phase-shifted PWM drive of the transmitting end;

[0041] The transmitting coil and receiving coil together form a magnetically coupled isolation transformer as the energy transmission medium; the transmission compensation network includes an inductor. ,capacitance and capacitor ;

[0042] The positive input terminal of the transmit compensation network and the inductor One end is connected to the inductor. The other end is connected to the capacitor one end and capacitor One end is simultaneously connected to the negative input of the transmit compensation network and the capacitor. The other end is connected to the capacitor. The other end is the positive output of the transmit compensation network, and the capacitor... The other end is the negative output of the transmit compensation network, and the positive and negative outputs of the transmit compensation network are respectively connected to the two ends of the transmit coil; the receive compensation network includes capacitors. ,capacitance It is connected in series with the receiving coil.

[0043] Preferably, the equivalent input impedance of the transmitter is:

[0044]

[0045] in, For equivalent leakage, For load resistance, The transformer turns ratio; via , , , The configuration enables the resonant network of the magnetically coupled isolation transformer to operate at a frequency that... Matching the resonant frequencies of each branch to satisfy This enables impedance transformation and efficient power transmission.

[0046] Preferably, the electronic load is an adjustable load or a battery simulator that switches between constant voltage and constant current modes. During charging, the battery port current at the receiving end is collected. and battery port voltage The dynamic response characteristics satisfy:

[0047]

[0048] in, These are the battery port currents. and battery port voltage Rate of change limit, used to prevent transient shocks.

[0049] Preferably, the host computer real-time simulation control unit is also used to detect the phase difference between the zero-crossing point of the inverter module's bridge arm voltage and the zero-crossing point of the transmitting coil current. Calculate the soft-switching margin and adjust the phase shift angle limit in real time. When the switching margin is insufficient, increase the dead time or correct the phase shift reference value appropriately while ensuring the transmission power, so as to maintain the zero-voltage switching condition.

[0050] Preferably, the lower-level controller is also used to perform phase-shift modulation at a fixed switching frequency and, in conjunction with online temperature compensation of the gate drive, to achieve real-time correction of the dead time; it is also used to introduce feedforward compensation for bus ripple and leakage inductance current based on the received phase-shift reference; it is also used to implement overvoltage protection, overcurrent protection, and overtemperature protection; and it is also used to complete a smooth transition at the carrier phase boundary based on the principle of voltage and current continuity when the upper-level real-time simulation control unit schedules the state vectors and gradual parameters of the old and new controllers.

[0051] The beneficial effects of this application are that it proposes a low-power dynamic wireless charging device based on a magnetically coupled isolation transformer. This device has a movable guide rail structure, a measurement system, and a control architecture that adopts a hierarchical control mode of upper and lower computer controllers. It can realize low-speed dynamic simulation while achieving accurate measurement and real-time adjustment of phase shift angle and power output. It can simulate the low-speed dynamic charging process under low power and safe and controllable conditions, and provide platform support for control algorithm verification, network optimization, efficiency evaluation, etc. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the principle of the low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer according to this application.

[0053] Figure 2 This is a schematic diagram of the magnetic coupling resonant compensation circuit structure of this application;

[0054] Figure 3 This is a key component of the experimental platform for a low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer. Detailed Implementation

[0055] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0056] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0057] The present application will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the application.

[0058] The present application discloses a low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer, comprising a transmitter, a linear guide rail platform, a receiver, a measurement system, and a control terminal.

[0059] The control unit includes a lower-level controller and an upper-level real-time simulation control unit; the lower-level controller is implemented based on a DSP chip, and the upper-level real-time simulation control unit is implemented using the RT Box platform.

[0060] The linear guide platform includes a fixed support plate and a sliding guide rail;

[0061] The receiver is fixed in the slide rail of the linear guide platform, allowing the receiver to move continuously in the horizontal or vertical direction.

[0062] The transmitting coil at the transmitting end is mounted on a fixed support plate of the linear guide rail platform;

[0063] The measurement system is used to measure the current and voltage of the transmitting coil and send them to the host computer real-time simulation control unit. It is also used to measure the power and voltage of the receiving load and send them to the host computer real-time simulation control unit.

[0064] The host computer real-time simulation control unit is used to run control algorithms based on the measured power, current and voltage to obtain phase shift reference, power trajectory or voltage trajectory, and send it to the lower computer controller;

[0065] The lower-level controller is used to drive the power of the transmitter based on the phase-shifting reference, power trajectory, or voltage trajectory.

[0066] In this application, the transmitting end includes a transmitting coil, a transmitting compensation network, an inverter module, and a DC power supply connected in sequence.

[0067] The receiving end includes a receiving coil, a receiving compensation network, a rectifier module, and an electronic load connected in sequence;

[0068] The lower-level controller drives the transmitter by controlling the inverter module, preferably using phase-shifted PWM drive.

[0069] Specifically, the transmitting coil at the transmitting end adopts a flat helical winding structure with dimensions of [missing information]. The number of coil turns N is designed according to the target value of the coupling coefficient. The transmitting coil is fixed on the guide rail plate. The coil spacing is measured and recorded by a precision ruler and displacement sensor to ensure the repeatability of dynamic offset test.

[0070] The receiver is used to simulate the on-board charging interface of an electric vehicle. The receiving coil is mounted on a fixed bracket, which is placed in a slide rail. Its structure matches that of the transmitter, employing the same type of flat helical winding with dimensions of [missing information]. .

[0071] The transmitting coil and the receiving coil together form a magnetically coupled isolation transformer as the energy transmission medium;

[0072] The coupling coefficient between the transmitter and receiver varies with lateral offset and air gap. for:

[0073]

[0074] in, This indicates the lateral offset between the transmitting and receiving coils. This indicates the change in the air gap between the transmitting and receiving coils. The maximum coupling coefficient during alignment. These are the lateral offset and air gap attenuation coefficients, respectively, obtained through experimental calibration.

[0075] The transmitter inverter module adopts a full-bridge structure and is controlled by a DSP to achieve phase-shift modulation at a fixed frequency of 85 kHz. The transmission power of the magnetically coupled isolation transformer... With phase angle The relationship is approximated as:

[0076]

[0077] in, Here, is the transformer turns ratio, and is the voltage before rectification at the receiving end. Angular frequency, For leakage sensation, Indicates the equivalent voltage at the transmitting end. This represents the equivalent voltage at the receiving end.

[0078] The electronic load in this application is an adjustable load or a battery simulator, switching between constant voltage and constant current modes. The receiver internally incorporates voltage and current sampling modules to achieve real-time monitoring and data recording during charging. To prevent transient impacts, the battery port current at the receiver is collected. and battery port voltage Its dynamic response characteristics satisfy:

[0079]

[0080] in, These are the battery port currents. and battery port voltage Rate of change limit, used to prevent transient shocks.

[0081] The rectifier module uses a full-bridge diode or synchronous rectifier structure to convert high-frequency AC into DC voltage. The output is smoothed through a filter capacitor. For low-power test platforms, the DC output power of the receiving end is set in the range of 100~500 W to ensure that the experimental process is safe and controllable.

[0082] The transmit compensation network and receive compensation network are core components of this equipment. The system uses a magnetically coupled isolation transformer as the energy transmission medium, such as... Figure 2 As shown, resonant matching is achieved by combining series and parallel capacitors and inductors, which combines the wide load adaptability of LCC compensation with the high power density of S-type compensation. It can maintain stable energy transfer efficiency under different load conditions and effectively extend the zero voltage turn-on (ZVS) range, thereby reducing switching losses and device stress.

[0083] The transmission compensation network includes inductors ,capacitance and capacitor ;

[0084] The positive input terminal of the transmit compensation network and the inductor One end is connected to the inductor. The other end is connected to the capacitor one end and capacitor One end is simultaneously connected to the negative input of the transmit compensation network and the capacitor. The other end is connected to the capacitor. The other end is the positive output of the transmit compensation network, and the capacitor... The other end is the negative output of the transmit compensation network, and the positive and negative outputs of the transmit compensation network are respectively connected to the two ends of the transmit coil; the receive compensation network includes capacitors. ,capacitance It is connected in series with the receiving coil.

[0085] In a preferred embodiment, the equivalent input impedance of the transmitter is expressed as:

[0086]

[0087] in, For equivalent leakage, For load resistance, The transformer turns ratio; via , , , The configuration enables the resonant network of the magnetically coupled isolation transformer to operate at a frequency that... Matching the resonant frequencies of each branch to satisfy This enables impedance transformation and efficient power transmission.

[0088] Furthermore, the system's transmission power is expressed as:

[0089]

[0090] in, This is the DC bus voltage. The coupling coefficient is... To compensate for the network's equivalent impedance, this formula shows that proper design of LCC-S parameters can effectively mitigate the decrease in coupling coefficient caused by lateral offset or air gap changes, thereby maintaining stable output power under dynamic operating conditions.

[0091] Therefore, the compensation network of this application can not only meet the basic energy transfer experimental requirements, but also provide a unified test environment for different modulation methods and control strategies, thereby enhancing the adaptability of the experimental platform and its scientific research and teaching value.

[0092] In a preferred embodiment, the wireless charging device of this application further includes devices with different relative magnetic permeabilities. Different ground materials with varying dielectric properties can be placed between the transmitter and receiver to simulate the impact of different road surface materials on the transmission efficiency of the wireless charging system. Its equivalent self-inductance can be expressed by the formula:

[0093]

[0094] in, The permeability of free space, The relative permeability of the winding and the filler material. The cross-sectional area of ​​the coil is... is the magnetic flux path length. Indicates the number of turns in the transmitting coil;

[0095] This application allows for the replacement of different ground materials above the sliding rail between the transmitter and receiver to simulate the differences in media such as asphalt, concrete, and composite pavement in real road environments. This is achieved by inserting materials with different relative magnetic permeabilities. Material samples with dielectric properties can directly reflect the coupling coefficient of the medium to the system. and transmission efficiency The impact of this. In the experiment, the system can collect the input power of the transmitter in real time. Output power of the receiver Calculate wireless power transfer efficiency:

[0096]

[0097] And combine comparisons of different materials The design assesses the impact of ground materials on the stability of wireless charging by evaluating power fluctuation indices. This design not only reproduces the actual interference of road media on magnetic field coupling under experimental conditions but also provides reference data for compensation network optimization and engineering applications. The control architecture of this application is a hierarchical control system. Specifically, the upper-level real-time simulation control unit is responsible for running complex control algorithms, power trajectory planning, and online parameter identification; the lower-level controller mainly executes phase-shifted PWM drive, fast overcurrent and overvoltage protection, and local feedback control. The two form a dual-time-scale collaborative closed loop through a high-speed communication link and hardware trigger signals: the upper-level real-time simulation control unit sends power or phase-shifted reference values ​​at a lower frequency, and the lower-level controller completes modulation and protection within the carrier cycle, thus balancing global optimization and real-time execution.

[0098] Within this layered architecture, the host computer real-time simulation control unit further integrates multiple functional modules to enhance the overall system's intelligence and robustness. Firstly, the host computer real-time simulation control unit can flexibly switch between different algorithms and output phase-shifting references through a unified interface. This enables adaptive control for different operating conditions.

[0099] In addition, the host computer real-time simulation control unit has power or voltage trajectory planning capabilities. In a preferred embodiment, the method by which the host computer real-time simulation control unit obtains the power trajectory or voltage trajectory includes:

[0100] When the coupling coefficient of the transmitter and receiver When fluctuations occur, or when there are sudden changes in load power or voltage, the trajectory planner generates a smooth power or voltage reference based on dynamic constraints to suppress excessive rates of change and ensure output stability. It generates the trajectory of the transmitted power by minimizing the objective function value of the power transmitted between the transmitting and receiving coils.

[0101] The objective function for power transfer between the transmitting and receiving coils is:

[0102]

[0103] in, For the corresponding objective function value, This is a smoothing factor used to balance tracking error and dynamic smoothness. This indicates the power transferred between the transmitting and receiving coils. The expected power representing the transmission power. , This represents the time integration constant corresponding to the smoothing factor;

[0104] The trajectory of the battery terminal voltage is generated by minimizing the objective function value of the battery terminal voltage. The objective function of the battery terminal voltage is:

[0105]

[0106] in, For the corresponding objective function value, Indicates the battery terminal voltage. This represents the expected value of the battery terminal voltage.

[0107] The power transmission trajectory is the target power value transmitted through the magnetically coupled link, and the battery terminal voltage trajectory is the target battery terminal voltage value. These target values ​​serve as the target inputs for trajectory planning. After dynamic constraint and smoothing processing in the host computer's real-time simulation control unit, they are sent down to the lower-level controller DSP. The DSP then executes these references in hardware through phase-shift control, PWM drive, and voltage and current loop regulation.

[0108] Secondly, the host computer real-time simulation control unit has online parameter identification capabilities. In a preferred embodiment, by injecting a small disturbance signal and acquiring the current and voltage responses at the transmitting and receiving ends, the mutual inductance can be estimated in real time using a least-squares fitting method. Leakage and equivalent load parameters Based on the equivalent coil model, the voltage and current at the sampling transmitter and receiver are inverted to obtain the mutual inductance. Equivalent leakage inductance and equivalent load Online estimates;

[0109] The equivalent model of the coil is:

[0110]

[0111] Indicates the self-inductance of the transmitting end. Indicates the receiver's self-inductance. Indicates the transmitter voltage. Receiver voltage, Indicates the transmitter current. This indicates the current at the receiving end.

[0112] In addition, the host computer real-time simulation control unit is also used for ZVS margin management. In a preferred embodiment, the host computer real-time simulation control unit is also used to detect the phase difference between the zero-crossing point of the inverter module's bridge arm voltage and the zero-crossing point of the transmitting coil current. The system calculates the soft-switching margin and adjusts the phase shift angle limit in real time. When the switching margin is insufficient, the dead time is appropriately increased or the phase shift reference value is corrected to maintain zero-voltage switching conditions, while ensuring transmission power. Finally, the host computer real-time simulation control unit is also equipped with a data and simulation comparison function. Under a unified clock domain, the system simultaneously records the "reference value - executed value - measured value" triple, ensuring that each experiment can be directly compared between simulation and experimental data. This function guarantees the repeatability of the control algorithm and the traceability of the results, providing solid support for the optimization and experimental verification of the control strategy.

[0113] The lower-level controller is mainly responsible for low-level drive and protection control, and its functional modules include the following aspects:

[0114] First, the lower-level controller features high-speed phase-shift PWM and dead-time self-calibration. Phase-shift modulation is performed at a fixed switching frequency of 85 kHz, and combined with online temperature compensation for the gate drive, real-time correction of the dead time is achieved, ensuring the switching consistency of the bridge arm voltage and current and improving the stability of soft-switching conditions. Based on the phase-shift reference issued by the upper-level real-time simulation control unit, the lower-level controller also introduces feedforward compensation for bus ripple and leakage inductance current to reduce response deviations under dynamic operating conditions and improve the transient performance of voltage and current.

[0115] In addition, the lower-level controller has a fast protection matrix that can complete emergency measures such as overvoltage protection (OVP), overcurrent protection (OCP), and overtemperature protection (OTP) within no more than 2–3 carrier cycles. Through the fast protection matrix, it can quickly enter derating or shutdown mode in the event of a serious anomaly, and the upper-level computer real-time simulation control unit performs policy-level secondary processing to ensure the safety and reliability of the platform.

[0116] Finally, the lower-level controller performs a seamless switching operation. When the upper-level real-time simulation control unit schedules the state vectors and gradual parameters of the old and new controllers, the lower-level controller can smoothly transition at the carrier phase boundary based on the principle of voltage and current continuity, ensuring the continuity of the power waveform during control switching and avoiding current surges or soft-switching loss. This mechanism enables the experimental platform to flexibly switch between different control algorithms, ensuring the repeatability and stability of the experiment.

[0117] To ensure the accuracy and traceability of experimental data, the embodiments of this application are equipped with standardized voltage and current sampling interfaces at both the transmitting and receiving ends, which can be connected to high-voltage differential probes and AC / DC current probes. Combined with a digital oscilloscope and spectrum analyzer, the bus voltage can be measured. Bridge arm voltage Coil current and leakage inductance current Key parameters are monitored and recorded in real time to provide reliable data support for control strategy verification and performance evaluation.

[0118] Furthermore, this embodiment uses an RT Box and a DSP to collaboratively acquire experimental parameters such as bus voltage, bridge arm voltage, coil current, phase difference, power factor, and derive power fluctuation indicators, and generates corresponding simulation calculation results in real time within the RT Box. Experimental data and simulation data can be compared and analyzed in the same clock domain, thereby accurately identifying the causes of energy loss, soft-switching failure, or device efficiency degradation.

[0119] It significantly improves the accuracy and repeatability of test results, enables scientific comparison between simulation and actual measurement in the experimental platform, and ensures the systematicness and reliability of data acquisition.

[0120] Example:

[0121] In the low-power electric vehicle wireless charging test platform of this application, the system operation states can be divided into two categories: static operation and low-speed dynamic operation. Static operation is mainly used to verify the design of the compensation network and the power transmission efficiency, and is an important working condition for the experimental platform to carry out basic characteristic analysis and parameter identification. Low-speed dynamic operation, on the other hand, uses a movable guide rail to simulate the slow driving or positional shift of the vehicle, and is used to study the impact of changes in the coupling coefficient on power transmission and control strategies. The two operating states are both independent and complementary: static operation ensures the acquisition of basic experimental data and the comparison of modulation strategies, while low-speed dynamic operation further verifies the robustness and real-time performance of the system under complex working conditions, thus enabling the platform of this application to comprehensively cover the key technical issues of electric vehicle wireless charging in different application scenarios.

[0122] 1. Static operating conditions

[0123] Under static operating conditions, the relative positions of the transmitting and receiving coils are fixed, the air gap remains constant, and the magnetic coupling relationship is stable. At this time, the system's operating conditions are simple, facilitating system analysis of the resonant characteristics of the compensation network and the energy transfer path. The platform employs a compensation network, the core of which lies in utilizing the synergistic effect of series inductors and parallel capacitors to make the system exhibit approximately pure impedance input near the resonant frequency, thereby improving the power factor and energy transfer efficiency.

[0124] 2. Low-speed dynamic operating conditions

[0125] Under low-speed dynamic operating conditions, the receiving coil is mounted on a sliding rail platform, enabling continuous movement in the lateral or longitudinal directions. This reproduces the spatial coupling changes caused by the vehicle entering the charging area, lateral offset, or suspension vibration. As the offset and air gap change, the coupling coefficient between the transmitter and receiver is no longer constant, and power transmission will fluctuate accordingly. Therefore, this application introduces a real-time power fluctuation evaluation index:

[0126]

[0127] in, The instantaneous power at the receiving end. This is the average power over a certain period of time. This indicator is used to measure the stability of the system under dynamic operating conditions.

[0128] The test platform described in this application can change the air gap distance, offset angle, etc., during low-speed dynamic operation, thereby covering the offset characteristics that electric vehicles may exhibit under different road conditions and operating conditions. Combined with a high-voltage differential probe and an AC / DC current probe, researchers can collect data such as voltage, current, efficiency, and power fluctuations, thereby verifying the performance of different control algorithms under actual dynamic operating conditions.

[0129] By combining static operation with low-speed dynamic operation, this application provides a stable yet flexible low-power experimental platform, the functional block diagram of which is shown below. Figure 1 As shown, static operation ensures the accuracy of parameter identification and compensation verification, while dynamic operation enhances the testing capabilities of the control algorithm's robustness and the system's real-time performance. These two aspects complement each other, enabling the platform to not only meet the intuitive and safety requirements of teaching experiments but also satisfy the in-depth verification needs of novel modulation and advanced control strategies in scientific research.

[0130] While this application has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of this application. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of this application as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer, characterized in that, Includes the transmitter, linear guide platform, receiver, measurement system, and control unit; The control unit includes a lower-level controller and an upper-level real-time simulation control unit; the lower-level controller is implemented based on a DSP chip, and the upper-level real-time simulation control unit is implemented using the RT Box platform. The linear guide platform includes a fixed support plate and a sliding guide rail; The receiver is fixed in the slide rail of the linear guide platform, allowing the receiver to move continuously in the horizontal or vertical direction. The transmitting coil at the transmitting end is mounted on a fixed support plate of the linear guide rail platform; The measurement system is used to measure the current and voltage of the transmitting coil and send them to the host computer real-time simulation control unit. It is also used to measure the power and voltage of the receiving load and send them to the host computer real-time simulation control unit. The host computer real-time simulation control unit is used to run control algorithms based on the measured power, current and voltage to obtain phase shift reference, power trajectory or voltage trajectory, and send it to the lower computer controller; The lower-level controller is used to drive the transmitter to perform phase-shifted PWM based on the phase-shifting reference, power trajectory, or voltage trajectory.

2. The low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer according to claim 1, characterized in that, Methods for obtaining power or voltage trajectories in a real-time simulation control unit of a host computer include: The coupling coefficient between the transmitter and receiver is obtained. When the coupling coefficient fluctuates, or the power and voltage of the load change abruptly, the trajectory of the transmitted power is generated by minimizing the objective function value of the transmitted power between the transmitter coil and the receiver coil, or the trajectory of the battery terminal voltage is generated by minimizing the objective function value of the battery terminal voltage, so as to achieve tracking error and dynamic smoothing. The objective function for power transfer between the transmitting and receiving coils is: in, For the corresponding objective function value, This is a smoothing factor used to balance tracking error and dynamic smoothness. This indicates the power transferred between the transmitting and receiving coils. The expected power representing the transmission power. , This represents the time integration constant corresponding to the smoothing factor; The objective function for the battery terminal voltage is: in, For the corresponding objective function value, Indicates the battery terminal voltage. This represents the expected value of the battery terminal voltage.

3. The low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer according to claim 2, characterized in that, Coupling coefficient for: in, This indicates the lateral offset between the transmitting and receiving coils. This indicates the change in the air gap between the transmitting and receiving coils. The maximum coupling coefficient during alignment. These are the lateral offset and air gap attenuation coefficients, respectively, obtained through experimental calibration.

4. The low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer according to claim 1, characterized in that, The host computer real-time simulation control unit is also used for online identification of parameters in the control algorithm, including mutual inductance. Leakage and equivalent load ; Online identification methods include: Based on the equivalent coil model, parameter inversion is performed on the voltage and current at the sampling transmitter and receiver to obtain the mutual inductance. Equivalent leakage inductance and equivalent load Online estimates; The equivalent model of the coil is: Indicates the self-inductance of the transmitting end. Indicates the receiver's self-inductance. Indicates the transmitter voltage. Receiver voltage, Indicates the transmitter current. This indicates the current at the receiving end.

5. The low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer according to claim 1, characterized in that, It also includes different relative permeabilities By using ground materials with varying dielectric properties and placing them above the transmitter, the effects of different ground materials on the coupling coefficient and transmission efficiency of the wireless charging system can be simulated.

6. The low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer according to claim 1, characterized in that, The receiving end includes a receiving coil, a receiving compensation network, a rectifier module, and an electronic load connected in sequence. The transmitting end includes a transmitting coil, a transmitting compensation network, an inverter module, and a DC power supply connected in sequence; wherein, the lower-level controller controls the inverter module to realize phase-shifted PWM drive of the transmitting end; The transmitting coil and receiving coil together form a magnetically coupled isolation transformer as the energy transmission medium; the transmission compensation network includes an inductor. ,capacitance and capacitor ; The positive input terminal of the transmit compensation network and the inductor One end is connected to the inductor. The other end is connected to the capacitor one end and capacitor One end is simultaneously connected to the negative input of the transmit compensation network and the capacitor. The other end is connected to the capacitor. The other end is the positive output of the transmit compensation network, and the capacitor... The other end is the negative output of the transmit compensation network, and the positive and negative outputs of the transmit compensation network are respectively connected to the two ends of the transmit coil; the receive compensation network includes capacitors. ,capacitance It is connected in series with the receiving coil.

7. The low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer according to claim 6, characterized in that, The equivalent input impedance of the transmitter is: in, For equivalent leakage, For load resistance, The transformer turns ratio; via , , , The configuration enables the resonant network of the magnetically coupled isolation transformer to operate at a frequency that... Matching the resonant frequencies of each branch to satisfy This enables impedance transformation and efficient power transmission.

8. The low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer according to claim 6, characterized in that, The electronic load is an adjustable load or a battery simulator, switching between constant voltage and constant current modes. During charging, it collects the battery port current at the receiving end. and battery port voltage The dynamic response characteristics satisfy: in, These are the battery port currents. and battery port voltage Rate of change limit, used to prevent transient shocks.

9. The low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer according to claim 6, characterized in that, The host computer real-time simulation control unit is also used to detect the phase difference between the zero-crossing point of the inverter module's bridge arm voltage and the zero-crossing point of the transmitting coil current. Calculate the soft-switching margin and adjust the phase shift angle limit in real time. When the switching margin is insufficient, increase the dead time or correct the phase shift reference value appropriately while ensuring the transmission power, so as to maintain the zero-voltage switching condition.

10. The low-speed dynamic wireless charging device for electric vehicles based on a magnetically coupled isolation transformer according to claim 6, characterized in that, The lower-level controller is also used to perform phase-shift modulation at a fixed switching frequency and, in conjunction with online temperature compensation of the gate drive, to achieve real-time correction of the dead time; it is also used to introduce feedforward compensation for bus ripple and leakage inductance current based on the received phase-shift reference; it is also used to implement overvoltage protection, overcurrent protection, and overtemperature protection; and it is also used to complete a smooth transition at the carrier phase boundary based on the continuity principle of voltage and current when the upper-level real-time simulation control unit schedules the state vectors and gradual parameters of the old and new controllers.

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