Impedance characteristic identification-based test platform and test method for LCC-SS-T topology
Through the test platform and method based on impedance characteristic recognition, the problem of low efficiency of parameter testing and inaccurate judgment of resonant cavity components in the LCC-SS-T topological wireless charging system is solved, efficient and accurate parameter judgment is achieved, and the testing efficiency and product quality of the production line are improved.
Patent Information
- Application Number
- CN202510684408.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-26
- Publication Date
- 2025-08-15
- Estimated Expiration
- 2045-05-26
AI Technical Summary
In the prior art, the parameter testing of the resonant cavity component of the LCC-SS-T topological wireless charging system is inefficient and has mutual interference with parameters, resulting in inaccurate judgments and inability to meet the needs of large-scale production.
Using a test platform and method based on impedance characteristic identification, the primary side inverter and secondary side test load module are combined with voltage and current probes, and the impedance model diagram is established to quickly judge the qualification status of the resonant component and avoid mutual interference between parameters.
It improves testing efficiency, avoids mutual interference between parameters, realizes fast and accurate parameter determination, and improves the production quality of wireless charging systems.
Smart Images
Figure CN120490646A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a test platform and a test method for an LCC-SS-T topology based on impedance characteristic identification, and in particular to a parameter test platform and a test method for a wireless charging system based on impedance characteristic identification for an LCC-SS-T topology. Background Art
[0002] Wireless charging systems are based on the principles of electromagnetic induction coupling or magnetic resonance, achieving efficient transfer of electrical energy through contactless energy transmission. They are widely used in the fields of electric vehicles, consumer electronics, and industrial automation.
[0003] LCC-SS-T is a common topology in wireless charging systems. It is designed to utilize the constant voltage output characteristics of LCC-SS and further increase the output current level.
[0004] like Figure 1 As shown in the figure, in the LCC-SS-T topology, the topology of the transmitter is LCC, SS means that the receiver is a series resonant structure, and T is an additional high-frequency transformer structure integrated at the receiver in order to further increase the output current.
[0005] Although the composite resonant topology significantly improves the robustness of wireless charging systems against parameter drift, there is still a key bottleneck in its large-scale production process: when the factory resonant parameters exceed the design tolerance range, it will cause the system's complex performance to deteriorate, ultimately resulting in batch quality defects in the product.
[0006] However, there are multiple resonant parameters within this composite resonant topology, which can affect the test results of individual parameters. Even after the resonant cavity assembly is installed, it is impossible to test these resonant parameters individually because test methods such as the Wheatstone bridge circuit are affected by other components within the resonant cavity assembly.
[0007] To ensure batch testing and verification of wireless charging systems before shipment, independent parameter testing of the resonant cavity components (including the transmitter coil and compensation network, the receiver coil, and the resonant compensation structure) is required. However, current testing methods have the following shortcomings:
[0008] 1. Inefficient testing: The resonant cavity assembly contains multiple components, requiring the multiple resonant inductors and capacitors to be individually disassembled for calibration and matching. Traditional methods require testing at each frequency point, resulting in a time-consuming testing process that cannot keep pace with the production line.
[0009] 2. Parameter Interference: Deviations in parameters such as coil inductance, resonant inductance, and series / shunt capacitance can have a cumulative impact. During online measurement, the physical connection between the compensation network and the power device introduces parasitic impedance, causing the measured impedance to deviate from the true resonant cavity characteristics. Interference from other components within the resonant cavity assembly can make it difficult to accurately locate the problematic component.
[0010] 3. Inaccurate judgment: Using current experience to judge whether the parameters are qualified can easily lead to misjudgment (judging components with hidden dangers as qualified).
[0011] Therefore, achieving a fast and accurate testing process remains a technical bottleneck that needs to be overcome. Therefore, developing a parameter testing platform and testing method for wireless charging systems with LCC-SS-T topology based on impedance characteristic identification, which can quickly determine whether factory parameters meet standards by utilizing the laws of its resonant impedance, has become a key requirement for improving the quality of wireless charging system mass production. Summary of the Invention
[0012] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a test platform and test method for LCC-SS-T topology based on impedance characteristic identification with high test efficiency, avoidance of parameter mutual interference and accurate judgment.
[0013] The technical solution adopted by the present invention is: the present invention includes a test platform and a test method for LCC-SS-T topology based on impedance characteristic identification; the test platform for LCC-SS-T topology based on impedance characteristic identification includes:
[0014] Primary side resonant component to be tested: including LCC transmitter topology
[0015] Secondary side resonant components to be tested: including SS receiving end series resonant structure and high-frequency transformer structure
[0016] The primary-side resonant component to be tested and the secondary-side resonant component to be tested form an LCC-SS-T topology; the test platform further includes:
[0017] The primary-side inverter is a full-bridge converter. The input of the primary-side resonant component to be tested is connected to the output port of the full-bridge converter. The inverter operates through phase-shifted full-bridge modulation to achieve a drive waveform with an output frequency of 40k-200kHz, which is used to drive the LCC-SS-T topology to complete the test process.
[0018] PFC module: used to connect to the grid for power factor correction and convert the AC power of the grid into DC power and input it into the primary-side inverter;
[0019] Secondary side test load module: The output end of the secondary side resonant component to be tested is connected to the input port of the secondary side test responsible module, which is used to receive the energy transmitted from the primary side by the test platform;
[0020] The test equipment includes two voltage probes, two current probes and a processing device. The two voltage probes are used to test the midpoint voltage of the primary-side resonant component to be tested and the midpoint voltage of the secondary-side resonant component to be tested, respectively. The two current probes are used to test the resonant current of the primary-side resonant component to be tested and the resonant current of the secondary-side resonant component to be tested, respectively. The processing device is used to receive and process the calculation of the midpoint voltage of the primary-side resonant component to be tested, the midpoint voltage of the secondary-side resonant component to be tested, the resonant current of the primary-side resonant component to be tested and the phase difference of the resonant current of the secondary-side resonant component to be tested, and further calculate the magnitude of the impedance.
[0021] Furthermore, the two voltage probes are both high-voltage differential probes, the two current probes are both high-frequency AC probes, the processing device is a computer, and the voltage probes and the current probes both receive data through the acquisition card of the test equipment and convert the continuous analog signal into discrete data points, and then transmit the processed digital signal to the computer through its data transmission interface.
[0022] Furthermore, the PFC module is a single-phase Vienna topology.
[0023] Furthermore, the secondary side test load module is a rectifier bridge module.
[0024] Furthermore, a test method for LCC-SS-T topology based on impedance characteristic identification includes the following steps:
[0025] S1. Connect the input of the primary side resonant component to be tested to the output port of the full-bridge converter;
[0026] S2. Connect the output of the secondary-side resonant cavity component to the input port of the secondary-side test module.
[0027] S3. The two voltage probes are connected to the primary side resonant component to be measured and the secondary side resonant component to be measured, respectively. The two voltage probes are used to measure the midpoint voltage of the primary side resonant component to be measured and the midpoint voltage of the secondary side resonant component to be measured, respectively. The two current probes are connected to the primary side resonant component to be measured and the secondary side resonant component to be measured, respectively. The two current probes are used to measure the resonant current of the primary side resonant component to be measured and the resonant current of the secondary side resonant component to be measured;
[0028] S4. Connect the two voltage probes and the two current probes to the data acquisition card, and then connect them to the computer.
[0029] S5. Turn on the grid switch, and then turn on the PFC module and the primary-side inverter;
[0030] S6. The primary-side inverter performs a frequency sweep operation, outputting a drive waveform from 40 kHz to 200 kHz.
[0031] S7. The test equipment records the magnitude and phase of each key waveform during the frequency sweep and creates an impedance model diagram.
[0032] S8. Compare the impedance model diagram established during the frequency sweep with the standard impedance model diagram to determine the qualification of the resonant component of the LCC-SS-T topology;
[0033] S9. Turn off the primary-side inverter and PFC module, and finally turn off the grid switch.
[0034] Furthermore, during the frequency sweep, an impedance model diagram is established, including a spectrum of the input impedance of the LCC-SS-T topology within a certain frequency range, a spectrum of the output impedance of the LCC-SS-T topology within a certain frequency range, a spectrum of the equivalent impedance from the secondary side to the primary side of the LCC-SS-T topology within a certain frequency range, and a spectrum of the equivalent impedance from the primary side to the secondary side of the LCC-SS-T compensation topology within a certain frequency range.
[0035] Furthermore, the method for calculating the input impedance value by the magnitude and phase of the resonant current of the primary-side resonant component to be measured and the midpoint voltage of the primary-side resonant component to be measured is as follows:
[0036]
[0037] where Z p_in is the input impedance, V pi is the midpoint voltage of the resonant component to be measured on the primary side, i lrp is the resonant current of the resonant component to be measured on the primary side, φ p is the full-bridge phase shift angle of the resonant component to be measured on the primary side, full-bridge phase shift angle, j is the imaginary unit, ω is the angular frequency;
[0038] The method for calculating the output impedance value by the magnitude and phase of the resonant current of the secondary side resonant component to be measured and the midpoint voltage of the secondary side resonant component to be measured is as follows:
[0039]
[0040] where Z s_in is the output impedance, V si is the midpoint voltage of the secondary side resonant component to be measured, i Ts is the resonant current of the resonant component to be measured on the secondary side, φ s is the full-bridge phase shift angle of the secondary side resonant component to be measured, θc is the system phase difference, θ t is the phase difference of the high-frequency transformer;
[0041] The calculation method of the equivalent impedance from the secondary side to the primary side of the LCC-SS-T topology is as follows:
[0042]
[0043] where Z s_p is the equivalent impedance from the secondary side to the primary side, where Z s_p is the equivalent impedance from the secondary side to the primary side, where Z s_p is the equivalent impedance from the secondary side to the primary side, where the impedance used from the secondary side to the primary side is as follows:
[0044] Z pi : The ground-end resonant inductor branch impedance is the equivalent impedance of the resonant inductor branch viewed from the secondary side toward the ground end;
[0045] Z pr : The ground-side shunt capacitor branch impedance is the equivalent impedance of the shunt capacitor branch and other preceding impedance components viewed from the secondary side toward ground;
[0046] Z prt : The ground resonant coil branch impedance is the equivalent impedance of the resonant coil branch and other impedance components in front of it as seen from the secondary side toward the ground;
[0047] Z prs : The ground-to-vehicle resonant branch impedance is the equivalent impedance of the vehicle-end coil branch and other preceding impedance components viewed from the secondary side toward the ground.
[0048] Z prst : Since the LCC-SS is not a symmetrical structure, this component of impedance does not exist in this topology.
[0049] In Table 1, it is marked as none;
[0050] Z prc : Since the LCC-SS is not a symmetrical structure, this component of impedance does not exist in this topology.
[0051] In Table 1, it is marked as none;
[0052] Z s_in : Vehicle-side input impedance, the input impedance of the entire resonant cavity viewed from the secondary side;
[0053] The calculation method of the equivalent impedance from the primary side to the secondary side of the LCC-SS-T compensation topology is as follows:
[0054]
[0055] where Z p_s The equivalent impedance from the primary side to the secondary side is as follows:
[0056] Z si : Since the LCC-SS is not a symmetrical structure, this component of impedance does not exist in this topology.
[0057] In Table 1, it is marked as none;
[0058] Z sr : Since the LCC-SS is not a symmetrical structure, this component of impedance does not exist in this topology.
[0059] In Table 1, it is marked as none;
[0060] Z srt : Vehicle-end resonant coil branch impedance is the equivalent impedance of the resonant coil branch and other impedance components in front of it as seen from the primary side toward the vehicle end;
[0061] Z srp : The vehicle-to-ground resonant branch impedance is the equivalent impedance of the ground coil branch and other impedance components in front of it as seen from the primary side toward the vehicle.
[0062] Z srpt : The vehicle-to-ground resonant transmitting branch impedance is the equivalent impedance of the ground coil and transmitting coil leakage inductance and series capacitance branch as well as other preceding impedance components as seen from the primary side toward the vehicle.
[0063] Z src : The vehicle-to-ground shunt capacitor branch impedance is the equivalent impedance of the ground shunt capacitor branch and other preceding impedance components viewed from the primary side toward the vehicle.
[0064] Z p_in : Ground input impedance, input impedance of the entire resonant cavity viewed from the secondary side.
[0065] The beneficial effects of the present invention are: 1. High test efficiency: There is no need to perform complex parameter detection at each frequency point as in traditional methods. Through continuous frequency sweeping operations, the impedance spectrum can be quickly obtained, the test process takes less time, and the test efficiency of the production line is greatly improved; 2. Avoiding mutual interference of parameters: The present invention does not need to test the parameters of each resonant component separately, but identifies whether the resonant performance is qualified or not through several characteristic impedances of the whole, which can avoid mutual interference of resonant parameters; 3. Accurate judgment: The characteristic impedance spectrum is used to judge whether the parameters are qualified, which is simple and quick to operate. BRIEF DESCRIPTION OF THE DRAWINGS
[0066] Figure 1 It is a schematic diagram of the LCC-SS-T topology;
[0067] Figure 2 is a schematic diagram of the test platform;
[0068] Figure 3 It is a schematic diagram of the key waveforms of the LCC-SS-T system;
[0069] Figure 4 Schematic diagram of four key waveforms actually measured in the embodiment;
[0070] Figure 5 It is a diagram showing the relationship between input impedance and operating frequency;
[0071] Figure 6 It is a diagram showing the relationship between output impedance and operating frequency;
[0072] Figure 7 This is a diagram showing the relationship between the equivalent impedance from the secondary side to the primary side and the operating frequency;
[0073] Figure 8 It is a schematic diagram of the relationship between the equivalent impedance from the primary side to the secondary side and the operating frequency. DETAILED DESCRIPTION
[0074] like Figure 1 and Figure 2 As shown, in this embodiment, the present invention includes a test platform and test method for LCC-SS-T topology based on impedance characteristic identification; the test platform for LCC-SS-T topology based on impedance characteristic identification includes:
[0075] Primary side resonant component to be tested: including LCC transmitter topology
[0076] Secondary side resonant components to be tested: including SS receiving end series resonant structure and high-frequency transformer structure
[0077] The primary-side resonant component to be tested and the secondary-side resonant component to be tested form an LCC-SS-T topology; the test platform further includes:
[0078] The primary-side inverter is a full-bridge converter. The input of the primary-side resonant component to be tested is connected to the output port of the full-bridge converter. The inverter operates through phase-shifted full-bridge modulation to achieve a drive waveform with an output frequency of 40k-200kHz, which is used to drive the LCC-SS-T topology to complete the test process.
[0079] PFC module: used to connect to the grid for power factor correction and convert the AC power of the grid into DC power and input it into the primary-side inverter;
[0080] Secondary side test load module: The output end of the secondary side resonant component to be tested is connected to the input port of the secondary side test responsible module, which is used to receive the energy transmitted from the primary side by the test platform;
[0081] The test equipment includes two voltage probes, two current probes and a processing device. The two voltage probes are used to test the midpoint voltage of the primary-side resonant component to be tested and the midpoint voltage of the secondary-side resonant component to be tested, respectively. The two current probes are used to test the resonant current of the primary-side resonant component to be tested and the resonant current of the secondary-side resonant component to be tested, respectively. The processing device is used to receive and process the calculation of the midpoint voltage of the primary-side resonant component to be tested, the midpoint voltage of the secondary-side resonant component to be tested, the resonant current of the primary-side resonant component to be tested and the phase difference of the resonant current of the secondary-side resonant component to be tested, and further calculate the magnitude of the impedance.
[0082] In this embodiment, the two voltage probes are both high-voltage differential probes, the two current probes are both high-frequency AC probes, the processing device is a computer, and the voltage probes and the current probes both receive data through an acquisition card of the test equipment and convert continuous analog signals into discrete data points, and then transmit the processed digital signals to the computer through its data transmission interface.
[0083] In this embodiment, the PFC module is a single-phase Vienna topology.
[0084] In this embodiment, the secondary side test load module is a rectifier bridge module.
[0085] In this embodiment, a test method for an LCC-SS-T topology based on impedance characteristic identification includes the following steps:
[0086] S1. Connect the input of the primary side resonant component to be tested to the output port of the full-bridge converter;
[0087] S2. Connect the output of the secondary-side resonant cavity component to the input port of the secondary-side test module.
[0088] S3. The two voltage probes are connected to the primary side resonant component to be measured and the secondary side resonant component to be measured, respectively. The two voltage probes are used to measure the midpoint voltage of the primary side resonant component to be measured and the midpoint voltage of the secondary side resonant component to be measured, respectively. The two current probes are connected to the primary side resonant component to be measured and the secondary side resonant component to be measured, respectively. The two current probes are used to measure the resonant current of the primary side resonant component to be measured and the resonant current of the secondary side resonant component to be measured;
[0089] S4. Connect the two voltage probes and the two current probes to the data acquisition card, and then connect them to the computer.
[0090] S5. Turn on the grid switch, and then turn on the PFC module and the primary-side inverter;
[0091] S6. The primary-side inverter performs a frequency sweep operation, outputting a drive waveform from 40 kHz to 200 kHz.
[0092] S7. The test equipment records the magnitude and phase of each key waveform during the frequency sweep and establishes an impedance model diagram, where each key waveform includes four key waveforms, namely Figure 4 The ground midpoint voltage V pi , ground resonant current I Lrp , vehicle-end midpoint voltage V si and the transformer secondary current I Ts ;
[0093] S8. Compare the impedance model diagram established during the frequency sweep with the standard impedance model diagram to determine the qualification of the resonant component of the LCC-SS-T topology;
[0094] S9. Turn off the primary-side inverter and PFC module, and finally turn off the grid switch.
[0095] In this embodiment, Figure 3 It is a schematic diagram of the key waveforms of the LCC-SS-T system. Figure 3 The key waveforms and Figure 1 There are several key waveforms corresponding to the positions shown in p1 -S p4 yes Figure 2 The driving signal in the primary side inverter, S s1 -S s4 Yes Figure 2 The driving signal of the rectifier bridge under active rectification of the secondary side test load.
[0096] φ p and φ s are the full-bridge phase shift angles for the primary and secondary sides, respectively. In the present invention, these values are fixed and maintained at a value close to π. (This is because the test process does not require strict control of the output power.)
[0097] V pi is the midpoint voltage of the primary side. Lrp is the resonant current on the primary side.
[0098] V st is the primary voltage of the transformer on the secondary side, i s is the transformer primary resonant current on the secondary side.
[0099] θ c is the system phase difference.
[0100] V si is the midpoint voltage of the secondary side. Ts is the resonant current on the secondary side. t is the phase difference of the high-frequency transformer.
[0101] In simple terms, the present invention uses the values and phase differences of various voltages and currents to calculate the complex values of various impedances, and then uses traditional numerical analysis to compare the differences with standard impedance spectra to determine the qualification of the resonant cavity component.
[0102] In this embodiment, the impedance model diagram established during the frequency sweep includes a spectrum of the input impedance of the LCC-SS-T topology within a certain frequency range, a spectrum of the output impedance of the LCC-SS-T topology within a certain frequency range, a spectrum of the equivalent impedance from the secondary side to the primary side of the LCC-SS-T topology within a certain frequency range, and a spectrum of the equivalent impedance from the primary side to the secondary side of the LCC-SS-T compensation topology within a certain frequency range.
[0103] In this embodiment, the method for calculating the input impedance value by the magnitude and phase of the resonant current of the primary-side resonant component to be measured and the midpoint voltage of the primary-side resonant component to be measured is as follows:
[0104]
[0105] where Z p_in is the input impedance, V pi is the midpoint voltage of the resonant component to be measured on the primary side, i lrp is the resonant current of the resonant component to be measured on the primary side, φ p is the full-bridge phase shift angle of the resonant component to be measured on the primary side, j is the imaginary unit. In simple terms, j is an imaginary unit, it is not a variable, j 2 =-1; ω is the angular frequency, in radians per second, and its relationship with the frequency f is: ω = 2πf;
[0106] The method for calculating the output impedance value by the magnitude and phase of the resonant current of the secondary side resonant component to be measured and the midpoint voltage of the secondary side resonant component to be measured is as follows:
[0107]
[0108] where Z s_in is the output impedance, V si is the midpoint voltage of the secondary side resonant component to be measured, i Ts is the resonant current of the resonant component to be measured on the secondary side, φ s is the full-bridge phase shift angle of the secondary side resonant component to be measured, θ c is the system phase difference, which is Figure 3The phase difference between the ground midpoint voltage Vpi and the vehicle-side transformer primary voltage Vst is indicated in the figure. This value is mainly determined by the resonance parameters of the LCC-SS. The ideal value is 90° (no internal resistance and complete resonance). It is usually a dozen degrees smaller, that is, between 70 and 90. t The phase difference of a high-frequency transformer refers to the phase difference between the voltage waveforms at the transformer's output (primary) and input (secondary). Ideally, the voltage phase difference between the primary and secondary windings is 0 or 180 degrees, depending on the winding direction and the polarity of the same-named terminals.
[0109] The following is an analysis of the frequencies in the impedance spectrum, which is merely a deduction for the sake of patent validity. In fact, if a standard impedance spectrum is available (which can be obtained through prior testing of standard components), the implementation of the present invention will not be affected even if the following analysis is not known.
[0110] like Figure 1 The calculation method of each impedance component shown in the table is as follows:
[0111]
[0112] Here, x is replaced by p or s, respectively, to represent the quantity viewed from the secondary or primary side. For example, the quantity Zxrt is Zsrt when viewed from the primary side and Zprt when viewed from the secondary side. Because the LCC-SS is not a symmetrical structure, some quantities are absent and are marked "none" in the corresponding positions in the table.
[0113] The calculation method of the equivalent impedance from the secondary side to the primary side of the LCC-SS-T topology is as follows:
[0114]
[0115] where Z s_p is the equivalent impedance from the secondary side to the primary side, where Z s_p is the equivalent impedance from the secondary side to the primary side, where the impedance used from the secondary side to the primary side is as follows:
[0116] Z pi : The ground-end resonant inductor branch impedance is the equivalent impedance of the resonant inductor branch viewed from the secondary side toward the ground end;
[0117] Z pr : The ground-side shunt capacitor branch impedance is the equivalent impedance of the shunt capacitor branch and other preceding impedance components viewed from the secondary side toward ground;
[0118] Z prt: The ground resonant coil branch impedance is the equivalent impedance of the resonant coil branch and other impedance components in front of it as seen from the secondary side toward the ground;
[0119] Z prs : The ground-to-vehicle resonant branch impedance is the equivalent impedance of the vehicle-end coil branch and other preceding impedance components viewed from the secondary side toward the ground.
[0120] Z prst : Since the LCC-SS is not a symmetrical structure, this component of impedance does not exist in this topology.
[0121] In Table 1, it is marked as none;
[0122] Z prc : Since the LCC-SS is not a symmetrical structure, this component of impedance does not exist in this topology.
[0123] In Table 1, it is marked as none;
[0124] Z s_in : Vehicle-side input impedance, the input impedance of the entire resonant cavity viewed from the secondary side;
[0125] The calculation method of the equivalent impedance from the primary side to the secondary side of the LCC-SS-T compensation topology is as follows:
[0126]
[0127] where Z p_s is the equivalent impedance from the primary side to the secondary side, Z si : Since the LCC-SS is not a symmetrical structure, this component of impedance does not exist in this topology. It is marked as none in Table 1;
[0128] Z sr : Since the LCC-SS is not a symmetrical structure, this component of impedance does not exist in this topology.
[0129] In Table 1, it is marked as none;
[0130] Z srt : Vehicle-end resonant coil branch impedance is the equivalent impedance of the resonant coil branch and other impedance components in front of it as seen from the primary side toward the vehicle end;
[0131] Z srp : The vehicle-to-ground resonant branch impedance is the equivalent impedance of the ground coil branch and other impedance components in front of it as seen from the primary side toward the vehicle.
[0132] Z srpt: The vehicle-to-ground resonant transmitting branch impedance is the equivalent impedance of the ground coil and transmitting coil leakage inductance and series capacitance branch as well as other preceding impedance components as seen from the primary side toward the vehicle.
[0133] Z src : The vehicle-to-ground shunt capacitor branch impedance is the equivalent impedance of the ground shunt capacitor branch and other preceding impedance components viewed from the primary side toward the vehicle.
[0134] Z p_in : Ground input impedance, input impedance of the entire resonant cavity viewed from the secondary side.
[0135] More specific implementation examples include Figure 4 As shown, the test equipment records the magnitude and phase diagram of the four key waveforms during the frequency sweep. The acquisition card records the magnitude and phase information of each waveform at each frequency point and sends it to the computer for recording and analysis. The corresponding frequency spectrum is obtained by calculation and analysis using the above calculation method. The spectrum of the embodiment is shown below:
[0136] like Figure 5 The input impedance Z of the LCC-SS-T topology is shown. p_in Various coupling coefficients k at characteristic frequency f w The impedance reaches its maximum value near
[0137] like Figure 6 The output impedance Z of the LCC-SS-T compensation topology is shown. s_in The impedance maximum value for each different coupling coefficient k appears at a different operating frequency and produces a puzzling variation pattern.
[0138] like Figure 7 It can be seen that within a certain frequency range, the equivalent impedance Z from the secondary side to the primary side of the LCC-SS-T topology is s_p At the characteristic frequency f w In addition, as the coupling coefficient k increases, Z s_p will decrease monotonically.
[0139] like Figure 8 Shows the equivalent impedance Z from primary to secondary of the LCC-SS-T topology p_s Obviously, if the system is in good resonance, Z p_s At the characteristic frequency f w This characteristic is maintained within a certain range of the coupling coefficient k.
[0140] Testers can quickly determine the qualification of the resonant cavity component by observing the deviation of these four spectra within a certain coupling coefficient and frequency range.
[0141] The present invention is applied to the technical field of wireless charging of power electronics technology.
[0142] Although the embodiments of the present invention are described with practical solutions, they do not limit the meaning of the present invention. For those skilled in the art, it is obvious to modify the implementation scheme and combine it with other solutions based on this description.
Claims
1. A test platform for LCC-SS-T topology based on impedance characteristic identification, comprising: Primary side resonant component to be tested: including LCC transmitter topology Secondary side resonant components to be tested: including SS receiving end series resonant structure and high-frequency transformer structure The primary-side resonant component to be tested and the secondary-side resonant component to be tested form an LCC-SS-T topology; characterized in that: the test platform further includes: The primary-side inverter is a full-bridge converter. The input of the primary-side resonant component to be tested is connected to the output port of the full-bridge converter. The inverter operates through phase-shifted full-bridge modulation to achieve a drive waveform with an output frequency of 40k-200kHz, which is used to drive the LCC-SS-T topology to complete the test process. PFC module: used to connect to the grid for power factor correction and convert the AC power of the grid into DC power and input it into the primary-side inverter; Secondary side test load module: The output end of the secondary side resonant component to be tested is connected to the input port of the secondary side test responsible module, which is used to receive the energy transmitted from the primary side by the test platform; The test equipment includes two voltage probes, two current probes and a processing device. The two voltage probes are used to test the midpoint voltage of the primary-side resonant component to be tested and the midpoint voltage of the secondary-side resonant component to be tested, respectively. The two current probes are used to test the resonant current of the primary-side resonant component to be tested and the resonant current of the secondary-side resonant component to be tested, respectively. The processing device is used to receive and process the calculation of the midpoint voltage of the primary-side resonant component to be tested, the midpoint voltage of the secondary-side resonant component to be tested, the resonant current of the primary-side resonant component to be tested and the phase difference of the resonant current of the secondary-side resonant component to be tested, and further calculate the magnitude of the impedance.
2. The test platform for LCC-SS-T topology based on impedance characteristic identification according to claim 1, characterized in that: The two voltage probes are both high-voltage differential probes, the two current probes are both high-frequency AC probes, the processing device is a computer, and the voltage probes and the current probes both receive data through the acquisition card of the test equipment and convert the continuous analog signal into discrete data points, and then transmit the processed digital signal to the computer through its data transmission interface.
3. The test platform for LCC-SS-T topology based on impedance characteristic identification according to claim 2, characterized in that: The PFC module is a single-phase Vienna topology.
4. The test platform for LCC-SS-T topology based on impedance characteristic identification according to claim 2, characterized in that: The secondary side test load module is a rectifier bridge module.
5. A test method for LCC-SS-T topology based on impedance characteristic identification, characterized by: The testing method comprises the testing platform according to any one of claims 2 to 4, and the testing method comprises the following steps: S1. Connect the input of the primary side resonant component to be tested to the output port of the full-bridge converter; S2. Connect the output of the secondary-side resonant cavity component to the input port of the secondary-side test module. S3. The two voltage probes are connected to the primary side resonant component to be measured and the secondary side resonant component to be measured, respectively. The two voltage probes are used to measure the midpoint voltage of the primary side resonant component to be measured and the midpoint voltage of the secondary side resonant component to be measured, respectively. The two current probes are connected to the primary side resonant component to be measured and the secondary side resonant component to be measured, respectively. The two current probes are used to measure the resonant current of the primary side resonant component to be measured and the resonant current of the secondary side resonant component to be measured; S4. Connect the two voltage probes and the two current probes to the acquisition card, and then connect them to the computer. S5. Turn on the grid switch, and then turn on the PFC module and the primary-side inverter; S6. The primary-side inverter performs a frequency sweep operation, outputting a drive waveform from 40 kHz to 200 kHz. S7. The test equipment records the magnitude and phase of each key waveform during the frequency sweep and creates an impedance model diagram. S8. Compare the impedance model diagram established during the frequency sweep with the standard impedance model diagram to determine the qualification of the resonant component of the LCC-SS-T topology; S9. Turn off the primary-side inverter and PFC module, and finally turn off the grid switch.
6. The test method for LCC-SS-T topology based on impedance characteristic identification according to claim 5, characterized in that: The impedance model diagrams established during the frequency sweep include the spectrum of the input impedance of the LCC-SS-T topology within a certain frequency range, the spectrum of the output impedance of the LCC-SS-T topology within a certain frequency range, the spectrum of the equivalent impedance from the secondary side to the primary side of the LCC-SS-T topology within a certain frequency range, and the spectrum of the equivalent impedance from the primary side to the secondary side of the LCC-SS-T compensation topology within a certain frequency range.
7. The test method for LCC-SS-T topology based on impedance characteristic identification according to claim 6, characterized in that: The method for calculating the input impedance value by the magnitude and phase of the resonant current of the primary side resonant component to be measured and the midpoint voltage of the primary side resonant component to be measured is as follows: where Z p_in is the input impedance, V pi is the midpoint voltage of the resonant component to be measured on the primary side, i lrp is the resonant current of the resonant component to be measured on the primary side, φ p is the full-bridge phase shift angle of the resonant component to be measured on the primary side, j is the imaginary unit, and ω is the angular frequency; The method for calculating the input impedance value by the magnitude and phase of the resonant current of the secondary side resonant component to be measured and the midpoint voltage of the secondary side resonant component to be measured is as follows: where Z s_in is the input impedance, V si is the midpoint voltage of the secondary side resonant component to be measured, i Ts is the resonant current of the resonant component to be measured on the secondary side, φ s is the full-bridge phase shift angle of the secondary side resonant component to be measured, θ c is the system phase difference, θ t is the phase difference of the high-frequency transformer; The calculation method of the equivalent impedance from the secondary side to the primary side of the LCC-SS-T topology is as follows: where Z s_p is the equivalent impedance from the secondary side to the primary side, where the impedance used from the secondary side to the primary side is as follows: Z pi : The ground-end resonant inductor branch impedance is the equivalent impedance of the resonant inductor branch viewed from the secondary side toward the ground end; Z pr : The ground-side shunt capacitor branch impedance is the equivalent impedance of the shunt capacitor branch and other preceding impedance components viewed from the secondary side toward ground; Z prt : The ground resonant coil branch impedance is the equivalent impedance of the resonant coil branch and other impedance components in front of it as seen from the secondary side toward the ground; Z prs : The ground-to-vehicle resonant branch impedance is the equivalent impedance of the vehicle-end coil branch and other preceding impedance components viewed from the secondary side toward the ground. Z s_in : Vehicle-side input impedance, the input impedance of the entire resonant cavity viewed from the secondary side; The calculation method of the equivalent impedance from the primary side to the secondary side of the LCC-SS-T compensation topology is as follows: where Z p_s is the equivalent impedance from the primary side to the secondary side, The impedance quantities used from the primary side to the secondary side include the following: Z srt : Vehicle-end resonant coil branch impedance is the equivalent impedance of the resonant coil branch and other impedance components in front of it as seen from the primary side toward the vehicle end; Z srp : The vehicle-to-ground resonant branch impedance is the equivalent impedance of the ground coil branch and other impedance components in front of it as seen from the primary side toward the vehicle. Z srpt : The vehicle-to-ground resonant transmitting branch impedance is the equivalent impedance of the ground coil and transmitting coil leakage inductance and series capacitance branch as well as other preceding impedance components as seen from the primary side toward the vehicle. Z src : The vehicle-to-ground shunt capacitor branch impedance is the equivalent impedance of the ground shunt capacitor branch and other preceding impedance components viewed from the primary side toward the vehicle. Z p_in : Ground input impedance, input impedance of the entire resonant cavity viewed from the secondary side.