Self-checking method of resonant inductance and charging system

Abstract

The application discloses a self-checking method of resonant inductance and a charging system, and relates to the technical field of charging. The method is applied to a power module, the power module comprises an AC / DC conversion circuit and a DC / DC conversion circuit, the DC / DC conversion circuit at least comprises a switching module and a resonant module connected in series, and the method comprises the following steps: in the case that it is determined that the power module meets a preset self-checking condition, the switching frequency of the switching module is continuously determined, and a reasonable interval of the switching frequency is determined; if the switching frequency continuously exceeds the reasonable interval for a time reaching a first preset time length, the average value of the input voltage of the power module in the first preset time length is determined, and in the case that the average value of the input voltage is in a preset interval, it is determined that the resonant inductance of the resonant module in the power module is invalid. Therefore, the resonant inductance invalidation fault can be accurately detected, and the probability of fault false alarm is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of charging, in particular to a self-checking method of resonant inductor and a charging system. BACKGROUND

[0002] In the field of electric vehicle charging technology, power modules using LLC (Inductor-Inductor-Capacitor) resonant topology are widely used due to their high efficiency. Resonant inductor is a key element for LLC resonant topology to achieve soft switching and adjust voltage gain, so it is necessary to detect the resonant inductor in the power module in real time to ensure that the power module can work normally.

[0003] The commonly used detection methods are overvoltage and overcurrent detection methods. However, when only a single resonant inductor in a power module with a multi-resonant cavity parallel structure fails, the power module may still maintain normal output under closed-loop control. Therefore, the traditional overvoltage and overcurrent detection methods cannot identify the failure of the resonant inductor, so that the power module is in an abnormal working state for a long time, which may eventually cause more serious damage, seriously affect the reliability of the power module, reduce the maintainability of the power module, and increase the maintenance cost. SUMMARY

[0004] The main purpose of the present application is to provide a self-checking method of resonant inductor and a charging system to accurately detect the failure of resonant inductor and reduce the probability of false alarm.

[0005] To achieve the above purpose, the present application provides a self-checking method of resonant inductor applied to a power module, wherein the power module includes an AC / DC conversion circuit and a DC / DC conversion circuit, the DC / DC conversion circuit includes at least a switching module and a resonant module connected in series, and the method includes:

[0006] When it is determined that the power module meets a preset self-checking condition, the switching frequency of the switching module is continuously determined, and a reasonable interval of the switching frequency is determined;

[0007] If the switching frequency continuously exceeds the reasonable interval for a first preset time length, an average value of input voltage of the power module in the first preset time length is determined, and when the average value of input voltage is in a preset interval, it is determined that the resonant inductor of the resonant module in the power module fails.

[0008] Optionally, the preset self-checking condition includes that the output power of the power module is greater than a preset power, and the power module has not reported the failure of the resonant inductor.

[0009] Optionally, the DC / DC conversion circuit further includes a rectifier output module, the switching module includes a first switching unit and a second switching unit, the resonant module includes a first resonant unit and a second resonant unit, the first switching unit is connected in series with the first resonant unit, the second switching unit is connected in series with the second resonant unit, and the rectifier output module is connected to the first resonant unit and the second resonant unit respectively; after determining that the resonant inductor of the resonant module in the power module has failed, the method further includes: obtaining the temperature values ​​of the first switching unit and the second switching unit; and determining the reference number of the failed resonant inductor in the power module based on the temperature values ​​of the first switching unit and the second switching unit.

[0010] Optionally, the first switching unit includes a first switch, a second switch, a third switch, and a fourth switch. The first switch and the second switch are connected in series, and the third switch and the fourth switch are connected in series and then in parallel across the two ends of the first switch and the second switch. The second switching unit includes a fifth switch, a sixth switch, a seventh switch, and an eighth switch. The fifth switch and the sixth switch are connected in series, and the seventh switch and the eighth switch are connected in series and then in parallel across the two ends of the fifth switch and the sixth switch. Obtaining the temperature values ​​of the first switching unit and the second switching unit includes: obtaining the temperature values ​​of the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the seventh switch, and the eighth switch.

[0011] Optionally, determining the reference number of the failed resonant inductor in the power module based on the temperature values ​​of the first and second switching units includes: taking the highest temperature value among the temperature values ​​of the first, second, third, and fourth switches as the first temperature value; taking the highest temperature value among the temperature values ​​of the fifth, sixth, seventh, and eighth switches as the second temperature value; determining the temperature difference between the first and second temperature values; and determining the reference number of the failed resonant inductor in the power module based on the temperature difference.

[0012] Optionally, the temperature difference is obtained by subtracting the second temperature value from the first temperature value; determining the reference number of the failed resonant inductor in the power module based on the temperature difference includes: if the absolute value of the temperature difference is greater than a temperature threshold, and the temperature difference is greater than the temperature threshold, then the reference number of the failed resonant inductor is the resonant inductor reference number of the second resonant unit; if the absolute value of the temperature difference is greater than the temperature threshold, and the temperature difference is less than or equal to the temperature threshold, then the reference number of the failed resonant inductor is the resonant inductor reference number of the first resonant unit.

[0013] Optionally, determining the reasonable range of the switching frequency includes: determining the reasonable range of the switching frequency based on the average value of the switching frequency within a preset time period, the difference of the preset resonant frequency, and the preset initial range; wherein, the preset time period is from the time point when the power module starts operating to the preset time point, and the preset initial range is determined based on the output voltage of the power module.

[0014] Optionally, the power module further includes a first sampling unit, a second sampling unit, and a third sampling unit; the first sampling unit is connected in parallel between the two output terminals of the AC / DC conversion circuit, and the first sampling unit is used to acquire the input voltage of the power module; the second sampling unit is connected in parallel between the first output terminal and the second output terminal of the DC / DC conversion circuit, and the second sampling unit is used to acquire the output voltage of the power module; the third sampling unit is connected in series with the second output terminal of the DC / DC conversion circuit, and the third sampling unit is used to acquire the output current of the power module.

[0015] Optionally, the first resonant unit includes a first capacitor, a first resonant inductor, a first transformer, and a second transformer; one end of the first capacitor is connected between the first switch and the second switch, the other end of the first capacitor is connected to one end of the first resonant inductor, the other end of the first resonant inductor is connected to one end of the primary winding of the first transformer, the other end of the primary winding of the first transformer is connected to one end of the primary winding of the second transformer, and the other end of the primary winding of the second transformer is connected between the third switch and the fourth switch; the second resonant unit includes a second capacitor, a second resonant inductor, a third transformer, and a fourth transformer; one end of the second capacitor is connected between the fifth switch and the sixth switch, the other end of the second capacitor is connected to one end of the second resonant inductor, the other end of the second resonant inductor is connected to one end of the primary winding of the third transformer, the other end of the primary winding of the third transformer is connected to one end of the primary winding of the fourth transformer, and the other end of the primary winding of the fourth transformer is connected between the seventh switch and the eighth switch.

[0016] In addition, to achieve the above objectives, this application also provides a charging system including at least two power modules, each power module including a controller for performing the self-test method for the resonant inductor as described above.

[0017] The self-testing method for the resonant inductor in this application continuously determines the switching frequency of the switching module and judges whether the time for which the switching frequency continuously exceeds the reasonable range reaches a first preset duration. Regardless of whether the power module is a single LLC resonant topology or multiple parallel LLC resonant topologies, as long as the resonant inductor fails, the switching frequency of the corresponding switching module will change. Therefore, if the time for which the switching frequency continuously exceeds the reasonable range reaches the first preset duration, it indicates that the resonant inductor of the power module has failed. Furthermore, by periodically judging whether the switching frequency exceeds the reasonable range and judging whether the average value of the input voltage of the power module is within the preset range, the validity of the detection result is determined, thereby reducing the probability of false alarms, improving detection accuracy, and the self-testing method has strong applicability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the power module according to an embodiment of this application;

[0019] Figure 2 This is a circuit diagram of an example power module of this application;

[0020] Figure 3 This is a schematic diagram of the charging system according to an embodiment of this application;

[0021] Figure 4 This is one of the flowcharts of the self-testing method for the resonant inductor according to an embodiment of this application;

[0022] Figure 5 This is a flowchart of a self-testing method for a resonant inductor, as exemplified in this application;

[0023] Figure 6 This is the second flowchart of the self-testing method for the resonant inductor according to an embodiment of this application;

[0024] Figure 7 This is the third flowchart of the self-testing method for the resonant inductor according to an embodiment of this application;

[0025] Figure 8 A schematic diagram of the physical structure of a controller is provided;

[0026] In the diagram, 100 is the AC / DC converter circuit; 200 is the DC / DC converter circuit; 210 is the switching module; 220 is the resonant module; 230 is the rectifier output module; 240 is the first sampling unit; 250 is the second sampling unit; 260 is the third sampling unit; 310 is the power module; 320 is the charging interface; 330 is the main control module; 340 is the power distribution device; 810 is the processor; 820 is the communication interface; 830 is the memory; and 840 is the communication bus.

[0027] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions 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, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] In the fields of electric vehicle and power electronics technology, high-power-density, high-efficiency power modules are crucial for ensuring rapid and stable charging of electric vehicles. Among them, power modules based on LLC resonant topology are widely used in on-board and off-board charging equipment due to their excellent soft-switching characteristics and wide voltage range adaptability. The resonant inductor, as the core component of the LLC resonant topology, plays a vital role in enabling soft switching of the switching transistors and participating in the formation of voltage gain characteristics.

[0030] However, in a specific LLC resonant topology with multiple resonant cavities in parallel, if a single resonant inductor fails while the other resonant cavities and control loop continue to operate normally, the entire power module may still maintain stable output voltage and current under closed-loop regulation. In this case, conventional overvoltage, overcurrent, and short-circuit protection mechanisms cannot effectively identify the resonant inductor failure. If not detected and addressed promptly, the power module will remain in an abnormal operating state for an extended period, leading not only to reduced efficiency and abnormal temperature rise, but also potentially to accumulated electrical stress, ultimately causing cascading damage to other critical components such as power switches and resonant capacitors. This severely weakens the long-term operational reliability and maintainability of the power module, significantly increasing after-sales costs.

[0031] Therefore, this application provides a self-testing method and charging system for a resonant inductor. The method uses the switching frequency of the switching transistor in the switching module to determine whether the resonant inductor has failed. This detection method can be applied to LLC resonant topologies with multiple resonant cavities connected in parallel. Furthermore, by continuously and periodically checking whether the switching frequency is within a reasonable range, the probability of false alarms is reduced. At the same time, the validity of the detection result is determined by the average value of the input voltage of the power module, thereby further reducing the probability of false alarms and improving the accuracy of resonant inductor failure detection.

[0032] To make it easier to understand, the structure of the power module and the charging system will be described in detail below.

[0033] Figure 1 This is a schematic diagram of the power module according to an embodiment of this application. Figure 1As shown, the power module may include an AC / DC conversion circuit 100 and a DC / DC conversion circuit 200. The DC / DC conversion circuit 200 includes at least a switching module 210 and a resonant module 220 connected in series.

[0034] First, it should be noted that the power module of this application embodiment can be used in charging piles or in energy storage systems, such as integrated DC charging piles, split DC charging piles, etc.

[0035] In this embodiment, the power module mainly consists of an AC / DC converter circuit 100 and a DC / DC converter circuit 200. The AC / DC converter circuit 100 rectifies the AC power input from the power grid into DC power, and then uses a large-capacity electrolytic capacitor for voltage regulation and filtering before outputting the DC / DC converter. The DC / DC converter circuit 200 converts the output through one or more LLC resonant cavities, and achieves a wide output range from 50V to 1000V through a series-parallel combination of switches on the output side.

[0036] It should be noted that this embodiment mainly uses two parallel LLC resonant cavities as an example to introduce the subsequent power module structure and the self-testing method of the resonant inductor.

[0037] In some implementations, the AC / DC conversion circuit 100 may include an input EMC module, a soft-start circuit, and a PFC module. The input EMC module is primarily used to suppress electromagnetic interference input from the mains side and improve the electromagnetic compatibility of the power module. The soft-start circuit is used during the soft-start process of the power module to limit the inrush current during power-on and prevent instantaneous large currents from impacting circuit components (such as the rectifier bridge and capacitors).

[0038] A PFC module (Power Factor Correction module) is used to optimize the power factor of a power supply and improve energy efficiency. A PFC module can consist of several switching transistors and diodes. During AC-DC conversion, traditional rectifier circuits can cause input current waveform distortion, generating a large number of harmonics and reducing the power factor (PF). A PFC module adjusts the phase of the input current through active methods (such as Boost PFC) or passive methods (such as valley-fill circuits) to synchronize it with the voltage, thereby raising the power factor to near 1.

[0039] It should be noted that the specific structure of the AC / DC conversion circuit 100 can refer to existing AC / DC conversion circuits of power modules. The AC / DC conversion circuit 100 is not the main content of the embodiments of this application, therefore, the embodiments of this application will not provide a detailed description or specific limitations. As an example, the AC / DC conversion circuit 100 can adopt a unidirectional or bidirectional PFC topology, such as the existing T-shaped three-level topology, I-shaped three-level topology, or T-shaped two-level topology.

[0040] Furthermore, the DC / DC converter circuit 200 in this embodiment can adopt the existing basic LLC resonant topology or phase-shifted full-bridge topology. Taking the LLC resonant topology as an example, the DC / DC converter circuit 200 can include one LLC resonant cavity or multiple LLC resonant cavities, and each LLC resonant cavity can be arranged in series and parallel in the DC / DC converter circuit 200.

[0041] The DC / DC converter circuit 200 may specifically include a switching module 210 and a resonant module 220. One end of the switching module 210 is connected to the AC / DC converter circuit 100, and the other end of the switching module 210 is connected to one end of the resonant module 220. The other end of the resonant module 220 may be connected to a charging interface.

[0042] Figure 2 This is a circuit diagram of an example power module from this application. (Example:) Figure 2 As shown, in some embodiments, the DC / DC converter circuit 200 further includes a fifth capacitor C5, a sixth capacitor C6, and a rectifier output module 230; the switching module 210 includes a first switching unit and a second switching unit, the resonant module 220 includes a first resonant unit and a second resonant unit, the first switching unit is connected in series with the first resonant unit, the second switching unit is connected in series with the second resonant unit, and the rectifier output module 230 is connected to the first resonant unit and the second resonant unit respectively.

[0043] The fifth capacitor C5 and the sixth capacitor C6 can be filter capacitors; the two ends of the fifth capacitor C5 are connected in parallel to the two output terminals of the PFC module, and similarly, the two ends of the sixth capacitor C6 are also connected in parallel to the two output terminals of the PFC module.

[0044] In this embodiment, the first switching unit and the first resonant unit can form an LLC resonant cavity, and the second switching unit and the second resonant unit can form a second LLC resonant cavity. The first switching unit is connected in parallel across the fifth capacitor C5, one end of the first resonant unit is connected to the output side of the first switching unit, and the other end of the first resonant unit is connected to the rectifier output module 230. The second switching unit is connected in parallel across the sixth capacitor C6, one end of the second resonant unit is connected to the output side of the second switching unit, and the other end of the second resonant unit is connected to the rectifier output module 230.

[0045] Continue to refer to Figure 2 In some embodiments, the first switching unit may include a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch Q4. The first switch Q1 and the second switch Q2 are connected in series, and the third switch Q3 and the fourth switch Q4 are connected in series and then in parallel across the two ends of the first switch Q1 and the second switch Q2.

[0046] The second switch unit includes a fifth switch Q5, a sixth switch Q6, a seventh switch Q7, and an eighth switch Q8. The fifth switch Q5 and the sixth switch Q6 are connected in series, and the seventh switch Q7 and the eighth switch Q8 are connected in parallel across the fifth switch Q5 and the sixth switch Q6.

[0047] It should be noted that the first switch Q1, the second switch Q2, the third switch Q3, the fourth switch Q4, the fifth switch Q5, the sixth switch Q6, the seventh switch Q7, and the eighth switch Q8 can be power electronic switches, such as MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), IGBTs (Insulated-Gate Bipolar Transistors), etc. In this embodiment, the first switch Q1, the second switch Q2, the third switch Q3, the fourth switch Q4, the fifth switch Q5, the sixth switch Q6, the seventh switch Q7, and the eighth switch Q8 are N-MOS switching transistors.

[0048] Specifically, taking N-MOS switches as an example, the third terminals of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 are all connected to the controller of the power module. The first terminal of the first switch Q1 is connected to one end of the fifth capacitor C5, the second terminal of the first switch Q1 is connected to the first terminal of the second switch Q2, and the second terminal of the second switch Q2 is connected to the other end of the fifth capacitor C5. The first terminal of the third switch Q3 is connected to one end of the fifth capacitor C5, the second terminal of the third switch Q3 is connected to the first terminal of the fourth switch Q4, and the second terminal of the fourth switch Q4 is connected to the other end of the fifth capacitor C5.

[0049] The third terminals of switches Q5, Q6, Q7, and Q8 are all connected to the controller of the power module. The first terminal of switch Q5 is connected to one end of capacitor C6, the second terminal of switch Q5 is connected to the first terminal of switch Q6, and the second terminal of switch Q6 is connected to the other end of capacitor C6. Similarly, the first terminal of switch Q7 is connected to one end of capacitor C6, the second terminal of switch Q7 is connected to the first terminal of switch Q8, and the second terminal of switch Q8 is connected to the other end of capacitor C6.

[0050] It should be noted that the third electrode of the first switch Q1, the second switch Q2, the third switch Q3, the fourth switch Q4, the fifth switch Q5, the sixth switch Q6, the seventh switch Q7, and the eighth switch Q8 is the gate electrode, and the first electrode can be either the source or the drain electrode, and the second electrode can also be either the drain or the source electrode.

[0051] Furthermore, the first resonant unit may include a first capacitor C1, a first resonant inductor L1, a first transformer T1, and a second transformer T2.

[0052] One end of the first capacitor C1 is connected between the first switch Q1 and the second switch Q2. The other end of the first capacitor C1 is connected to one end of the first resonant inductor L1. The other end of the first resonant inductor L1 is connected to one end of the primary coil of the first transformer T1. The other end of the primary coil of the first transformer T1 is connected to one end of the primary coil of the second transformer T2. The other end of the primary coil of the second transformer T2 is connected between the third switch Q3 and the fourth switch Q4.

[0053] In some embodiments, the second resonant unit includes a second capacitor C2, a second resonant inductor L2, a third transformer T3, and a fourth transformer T4.

[0054] One end of the second capacitor C2 is connected between the fifth switch Q5 and the sixth switch Q6. The other end of the second capacitor C2 is connected to one end of the second resonant inductor L2. The other end of the second resonant inductor L2 is connected to one end of the primary coil of the third transformer T3. The other end of the primary coil of the third transformer T3 is connected to one end of the primary coil of the fourth transformer T4. The other end of the primary coil of the fourth transformer T4 is connected between the seventh switch Q7 and the eighth switch Q8.

[0055] In this embodiment, the switching module 210 and the resonant module 220 are used to quickly switch the DC power output from the AC / DC converter circuit 100 through the switching transistors in the switching module 210, thereby converting the DC power into high-frequency AC power. The high-frequency AC power is input to the primary coils of the first transformer T1, the second transformer T2, the third transformer T3, and the fourth transformer T4. Further, the first transformer T1, the second transformer T2, the third transformer T3, and the fourth transformer T4 then couple the high-frequency AC power to the secondary coils through electromagnetic induction.

[0056] Specifically, the first capacitor C1, the first resonant inductor L1, the first transformer T1, and the second transformer T2 form an LLC resonant cavity, and the second capacitor C2, the second resonant inductor L2, the third transformer T3, and the fourth transformer T4 form another LLC resonant cavity. These two LLC resonant cavities determine the operating frequency of the resonant module 220. By selecting appropriate capacitor values, the resonant frequency can be adjusted to match the required switching frequency range. The first resonant inductor L1 and the second resonant inductor L2 can store energy and release it when needed, and also help control current peaks, protecting other components in the circuit from overcurrent damage.

[0057] The main functions of the first transformer T1, the second transformer T2, the third transformer T3, and the fourth transformer T4 are to raise or lower the voltage to the required voltage. In addition, the first transformer T1, the second transformer T2, the third transformer T3, and the fourth transformer T4 can also provide necessary electrical isolation to ensure the safety of the high-voltage side and the low-voltage side.

[0058] Continue to refer to Figure 2 In some implementations, the rectifier output module 230 includes a first rectifier unit, a second rectifier unit, a switching unit, an anti-reverse unit, and an output unit.

[0059] The switching unit is connected between one output terminal of the first rectifier unit and the other output terminal of the second rectifier unit; one end of the anti-reverse unit is connected to one output terminal of the first rectifier unit, and the other end of the anti-reverse unit is connected to the positive output terminal of the power module; the output unit is connected in parallel between the positive output terminal and the negative output terminal of the power module, and the negative output terminal of the power module is connected to the other output terminal of the second rectifier unit.

[0060] Specifically, one input terminal of the first rectifier unit is connected to one end of the secondary coil of the third transformer T3 in the second resonant unit, the other end of the secondary coil of the third transformer T3 is connected to one end of the secondary coil of the second transformer T2, and the other end of the secondary coil of the second transformer T2 is connected to the other input terminal of the first rectifier unit. The first rectifier unit is used to rectify the high-frequency AC power output from the third transformer T3 and the second transformer T2 to obtain DC power, so that the DC power can be output to the load.

[0061] One input terminal of the second rectifier unit is connected to one end of the secondary winding of the first transformer T1, and the other end of the secondary winding of the first transformer T1 is connected to one end of the secondary winding of the fourth transformer T4. The other end of the secondary winding of the fourth transformer T4 is connected to the other input terminal of the second rectifier unit. The second rectifier unit is used to rectify the high-frequency AC power output from the first transformer T1 and the fourth transformer T4 to obtain DC power, so that the DC power can be output to the load.

[0062] In some embodiments, the first rectifier unit includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, and a third capacitor C3.

[0063] In this configuration, the anode of the first diode D1 is connected to the cathode of the second diode D2, and the area between the first diode D1 and the second diode D2 serves as one input terminal of the first rectifier unit; the anode of the third diode D3 is connected to the cathode of the fourth diode D4, and the area between the third diode D3 and the fourth diode D4 serves as the other input terminal of the first rectifier unit; the cathode of the first diode D1 is connected to the cathode of the third diode D3, and the area between the first diode D1 and the third diode D3 serves as one output terminal of the first rectifier unit; the anode of the second diode D2 is connected to the anode of the fourth diode D4, and the area between the second diode D2 and the fourth diode D4 serves as the other output terminal of the first rectifier unit; and the third capacitor C3 is connected in parallel across the two ends of the third diode D3 and the fourth diode D4.

[0064] The second rectifier unit includes the fifth diode D5, the sixth diode D6, the seventh diode D7, the eighth diode D8, and the fourth capacitor C4.

[0065] In this configuration, the anode of the fifth diode D5 is connected to the cathode of the sixth diode D6, and the area between the fifth diode D5 and the sixth diode D6 serves as one input terminal of the second rectifier unit; the anode of the seventh diode D7 is connected to the cathode of the eighth diode D8, and the area between the seventh diode D7 and the eighth diode D8 serves as the other input terminal of the second rectifier unit; the cathode of the fifth diode D5 is connected to the cathode of the seventh diode D7, and the area between the fifth diode D5 and the seventh diode D7 serves as one output terminal of the second rectifier unit; the anode of the sixth diode D6 is connected to the anode of the eighth diode D8, and the area between the sixth diode D6 and the eighth diode D8 serves as the other output terminal of the second rectifier unit; and the fourth capacitor C4 is connected in parallel across the seventh diode D7 and the eighth diode D8.

[0066] It should be noted that the third capacitor C3 and the fourth capacitor C4 are electrolytic capacitors on the DC bus of the DC / DC converter circuit 200. The third capacitor C3 and the fourth capacitor C4 can be selected as capacitors with larger capacitance values.

[0067] Continue to refer to Figure 2 In some implementations, the switching unit may include a ninth switch K1, a tenth switch K2, an eleventh switch K3, and a twelfth switch K4.

[0068] It should be noted that the ninth switch K1, the tenth switch K2, the eleventh switch K3, and the twelfth switch K4 can be contactors or relays.

[0069] Specifically, one end of the ninth switch K1 can be connected to one end of the third capacitor C3, and the other end of the ninth switch K1 is connected to one end of the fourth capacitor C4. One end of the tenth switch K2 is connected to the other end of the third capacitor C3, and the other end of the tenth switch K2 is connected to the other end of the fourth switch. One end of the eleventh switch K3 is connected to the other end of the third capacitor C3, and the other end of the eleventh switch K3 is connected to the output unit. One end of the twelfth switch K4 is connected to one end of the fourth capacitor C4, and the other end of the twelfth switch K4 is connected to the output unit. By turning off or closing the ninth switch K1, tenth switch K2, eleventh switch K3, and twelfth switch K4, the series-parallel switching of the two LLC resonant cavities is realized. In addition, the output unit may include a seventh capacitor C7 and an eighth capacitor C8 connected in series, and the seventh capacitor C7 and the eighth capacitor C8 are connected in parallel between the positive output terminal and the negative output terminal of the power module.

[0070] The reverse polarity protection unit can be composed of multiple reverse polarity protection diodes connected in series and parallel. This unit prevents direct high voltage from the downstream load, which could damage the electrolytic capacitors in the power module. (Continue to refer to...) Figure 2 In some implementations, the anti-reverse unit may include a ninth diode D9, the anode of which is connected to an output terminal of the first rectifier unit, and the cathode of which is connected to the positive output terminal of the power module.

[0071] The positive output terminal (Vo+) of the power module is connected to the positive terminal of the load through the charging interface, while the negative output terminal (Vo-) of the power module is also connected to the negative terminal of the load through the charging interface.

[0072] Continue to refer to Figure 2 In some embodiments, the power module further includes a first sampling unit 240, a second sampling unit 250, and a third sampling unit 260.

[0073] The first sampling unit 240 is connected in parallel between the two output terminals of the AC / DC conversion circuit 100, and is used to collect the input voltage of the power module; the second sampling unit 250 is connected in parallel between the first output terminal S1 and the second output terminal S2 of the DC / DC conversion circuit 200, and is used to collect the output voltage of the power module; the third sampling unit 260 is connected in series with the second output terminal S2 of the DC / DC conversion circuit 200, and is used to collect the output current of the power module.

[0074] In this embodiment, the first sampling unit 240 is specifically connected in parallel to the two output terminals of the PFC module to collect the input voltage of the DC / DC conversion circuit for subsequent calculation of the average input voltage of the power module. The second sampling unit 250 can be specifically connected in parallel between the positive and negative output terminals of the power module to collect the output voltage of the DC / DC conversion circuit.

[0075] The first sampling unit 240 and the second sampling unit 250 can both use existing voltage sampling circuits, and the third sampling unit 260 can use existing current sampling circuits. The first sampling unit 240, the second sampling unit 250 and the third sampling unit 260 will not be described in detail here.

[0076] The circuit structure of the power module in the embodiments of this application has been described above. The structure of the charging system will be described in detail below.

[0077] Figure 3 This is a schematic diagram of the charging system according to an embodiment of this application. Figure 3 As shown, the charging system includes at least two power modules 310, a main control module 330, a power distribution device 340, and at least one charging interface 320. Each power module 310 includes a controller, which can be used to execute the self-test method for the resonant inductor provided in the embodiments of this application.

[0078] The power distribution device 340 is connected to the main control module 330, each power module 310, and each charging interface 320. The power modules 310 convert AC power from the grid into DC power to supply the charging interfaces 320. The main control module 330 acquires the power demand of each charging interface 320 and generates scheduling commands based on the connection relationships of the controllable switches in the power distribution device 340 and the power demand. The power distribution device 340 controls the opening or closing of the controllable switches according to the scheduling commands to distribute the output power of each power module 310 to each charging interface 320.

[0079] In this embodiment, the internal controller of the power module 310 can be used to execute the self-test method for the resonant inductor provided in this application embodiment. When the internal controller of the power module 310 detects that the power module 310 has reached the preset self-test conditions, the internal controller of the power module 310 can perform a failure self-test on the resonant inductor of the power module 310 according to the self-test method for the resonant inductor provided in this application embodiment.

[0080] After each power module 310 completes its self-test for the resonant inductor's failure, the results can be reported to the host computer via the main control module 330, allowing staff to obtain the tag number of the failed resonant inductor. The self-test results may include information such as whether the resonant inductor in each power module 310 has failed, as well as the serial number of each power module 310. Staff can quickly locate the failed resonant inductor based on the serial number of the power module 310.

[0081] In some embodiments, the charging system provided in this application is an integrated DC charging pile, with the charging interface 320 used to connect the charging gun, and the charging gun being hung on the host of the charging system via the gun holder on the main body of the charging system.

[0082] In some embodiments, the charging system provided in this application is a split-type DC charging pile. The charging system also includes multiple charging terminals. The charging interface 320 is used to connect the charging terminals. The charging terminals are set separately from the main body of the charging system. The charging terminals are equipped with a single charging gun or dual charging guns for outputting power to electric vehicles.

[0083] The above is a structural description of the charging system according to the embodiments of this application. The self-testing method of the resonant inductor provided in the embodiments of this application will be described in detail below with reference to the structure of the power module and the structure of the charging system in the foregoing embodiments.

[0084] Figure 4 This is one of the flowcharts for a self-test method of a resonant inductor according to an embodiment of this application. This self-test method of the resonant inductor can be executed by the controller of the power module in the foregoing embodiments, such as... Figure 4 As shown, the self-testing method for this resonant inductor may include the following steps:

[0085] Step 410: After confirming that the power module meets the preset self-test conditions, continuously determine the switching frequency of the switching module and determine a reasonable range of the switching frequency.

[0086] Step 420: If the switching frequency continuously exceeds the reasonable range for a period of time that reaches the first preset duration, then determine the average input voltage of the power module within the first preset duration, and if the average input voltage is within the preset range, determine that the resonant inductor of the resonant module in the power module has failed.

[0087] refer to Figure 2 It is understandable that when one of the resonant inductors in the two LLC resonant cavities fails, the forced current sharing capability and output closed-loop control of the parallel dual LLC resonant cavity topology will result in no difference in the effective and peak values ​​of the currents in the two LLC resonant cavities compared to before the inductor failure. However, due to the significant differences in the parameters of the LLC resonant cavities, the actual switching frequency of the switching module will change. The voltage gain (M) formula for the LLC is as follows:

[0088]

[0089] In the formula, n is the transformer turns ratio; Lr is the inductance value of the resonant inductor, and Lm is the inductance value of the magnetizing inductor; , For load, This is the capacitance value of the resonant inductor; , For operating frequency, The resonant frequency, .

[0090] From the voltage gain formula of LLC above, it can be seen that when the inductance value of the resonant inductor changes, all other parameters remain constant. Therefore, only the operating frequency changes with the inductance value of the resonant inductor. Based on the above principle, this application's embodiment designs a method to determine whether the resonant inductor has failed by detecting whether the operating frequency of the switching module exceeds a reasonable range. When the actual switching frequency changes outside the preset reasonable range, the power module can identify that the resonant inductor is damaged.

[0091] In this embodiment, when the power module controller detects that the power module meets the preset self-test conditions, the controller begins to execute the self-test process of the resonant inductor in this embodiment. First, the controller continuously calculates the switching frequency of the switching transistor in the switching module in real time. In this embodiment, a loop formula is used to calculate the actual switching frequency. After obtaining the actual switching frequency, the switching frequency is filtered to obtain the final required switching frequency.

[0092] Furthermore, the controller can determine the reasonable range of switching frequency under the current operating conditions based on the output voltage of the power module. Specifically, based on the experience of the staff and extensive experiments, a correspondence table between output voltage and reasonable range can be established, with different output voltages corresponding to different reasonable ranges of switching frequency. When the controller needs to determine the reasonable range of switching frequency under the current operating conditions, it can first obtain the current output voltage of the power module through the second sampling unit, and then find the corresponding reasonable range from the aforementioned correspondence table based on the output voltage.

[0093] Finally, the controller determines whether the calculated actual switching frequency is within a reasonable range to ascertain whether the resonant inductor of the power module has failed. If the switching frequency is within the reasonable range, the resonant inductor of the power module is determined to be normal. If the switching frequency continuously exceeds the reasonable range for a first preset duration, the resonant inductor of the power module is preliminarily determined to have failed.

[0094] It should be noted that the embodiments of this application do not use whether the actual switching frequency at a certain point in time is within a reasonable range to directly determine whether the resonant inductor has failed, but rather use whether the switching frequency at each point in time within a cycle is within a reasonable range to determine whether the resonant inductor has failed.

[0095] Understandably, during power module operation, dynamic operating conditions at the output or input can cause fluctuations in the resonant loop, leading to the actual switching frequency exceeding the preset reasonable range. This can result in a false alarm indicating a resonant inductor failure. For example, during normal charging, power modules often experience significant fluctuations in output voltage, input voltage, or output current. Due to the closed-loop operation of the power module, its switching frequency can fluctuate dramatically within a short period. If real-time analysis is performed, such frequency fluctuations could trigger a resonant inductor failure detection, causing a false alarm from a normally functioning power module.

[0096] To avoid false alarms caused by input or output fluctuations in the power module, this embodiment employs a periodic judgment logic. Within a single cycle (i.e., the first preset duration), the controller continuously judges whether the actual switching frequency exceeds a reasonable range. Only when all switching frequencies in a single cycle exceed the reasonable range is the resonant inductor of the power module deemed damaged. If the actual switching frequency is within the reasonable range for at least one time point within a single cycle, the resonant inductor of the power module is deemed normal. It should be noted that the first preset duration (i.e., the cycle) should be set to be at least ten times the dynamic duration of the power module, but less than the time required for other components of the power module to fail after the resonant inductor fails.

[0097] After the switching frequency continuously exceeds the reasonable range for a first preset duration, the controller initially determines that the resonant inductor of the power module has failed. Then, the controller determines whether the average input voltage of the power module within the first preset duration is within a preset range. If it is within the preset range, the initial judgment is deemed valid, and the resonant inductor of the power module has failed. If it is not within the preset range, the initial judgment is deemed invalid, and the resonant inductor of the power module is normal. It should be noted that the preset range can be manually set by the staff according to actual needs, and no specific limitation is made on the preset range here.

[0098] Understandably, if the input voltage on the LLC resonant cavity input side continuously deviates from the preset range during power module operation, it may cause the actual switching frequency of the power module to exceed the reasonable range, resulting in a false alarm of resonant inductor failure. To avoid such false alarms, the detection process can be stopped when the input voltage on the LLC resonant cavity input side exceeds the preset range. However, if a method of real-time judgment of whether the input voltage is within the preset range is adopted, then when the input voltage fluctuates periodically at low frequencies, the power module will consistently fail to meet the conditions for entering the detection process due to input voltage fluctuations, greatly reducing the accurate detection rate of faulty power modules.

[0099] Based on this, this embodiment uses the determination of whether the average input voltage within a judgment period (i.e., the first preset time) is within a preset range to determine whether the detection result of the resonant inductor failure is valid. If the average input voltage within the first preset time is within the preset range, the detection result obtained according to the aforementioned detection process is valid, and the resonant inductor is determined to be faulty; if the average input voltage within the first preset time is not within the preset range, the detection result is determined to be invalid, and the resonant inductor is determined to be normal.

[0100] After the power module controller determines that its internal resonant inductor has failed, the power module controller can report to the main control module of the charging system. The main control module then reports the fault of the power module's resonant inductor failure to the host computer and controls the power module to shut down. After the power module shuts down, the resonant inductor failure fault position is maintained. After the power module disconnects the input, the resonant inductor failure fault position is cleared.

[0101] Therefore, by calculating the switching frequency of the switching module in real time and determining whether the switching frequency is within a reasonable range, a preliminary judgment can be made as to whether the resonant inductor of the resonant module in the power module has failed. This method is applicable not only to power modules with only one LLC resonant cavity but also to power modules with multiple LLC resonant cavities, making it more versatile. Furthermore, by using the switching frequency of one cycle to determine whether the resonant inductor has failed, false alarms caused by dynamic fluctuations in the power module's input or output are avoided. Simultaneously, by using the average input voltage of one cycle to determine whether the resonant inductor has failed within a preset range, false alarms caused by fluctuations in the power module's input voltage are avoided, effectively improving the accuracy of resonant inductor failure detection. This, in turn, improves the reliability and maintainability of the power module, and reduces the maintenance cost of the power module by detecting resonant inductor failure in a timely manner.

[0102] In some implementations, the preset self-test conditions include the power module's output power being greater than a preset power and the power module not reporting a failure of its resonant inductor.

[0103] In this embodiment, after the power module is started and begins operation, the power module controller can first calculate the current output power of the power module. Specifically, the controller obtains the current output voltage and output current of the power module from the second sampling unit and the third sampling unit, respectively, and then uses the output voltage and output current to calculate the output power.

[0104] Furthermore, the controller determines whether the calculated output power is greater than the preset power and whether the power module has previously reported its resonant inductor failure. If the current output power is greater than the preset power and the power module has not previously reported its resonant inductor failure, then the power module is determined to meet the preset self-test conditions and can enter the resonant inductor self-test process. If the current output power is less than or equal to the preset power, or the power module has previously reported its resonant inductor failure, then the power module is determined not to meet the preset self-test conditions. Therefore, it does not enter the resonant inductor self-test process, nor does it further determine other conditions, nor does it change the resonant inductor damage flag of the power module, and directly enters the next judgment cycle.

[0105] It should be noted that the preset power in this embodiment can be set to the half-load output power of the power module. This is because failure detection is more suitable when the output power is above half-load. Under the same hardware conditions, the frequency variation of different power levels is more drastic and the consistency is poor when the output power is below half-load. In addition, the risk of thermal damage to the resonant inductor is not high when the output power is below half-load, so it is not easy to fail. Therefore, the preset power in this embodiment is set to the half-load output power of the power module, so that the failure detection of the resonant inductor is performed when the power module outputs power above half-load.

[0106] In some implementations, determining a reasonable range of switching frequencies may include: determining a reasonable range of switching frequencies based on the average value of the switching frequencies within a preset time period, the difference between preset resonant frequencies, and a preset initial range; wherein the preset time period is from the time point when the power module starts operating to the preset time point, and the preset initial range is determined based on the output voltage of the power module.

[0107] It should be noted that the preset time point can be manually set by staff according to actual needs. For example, the preset time point can be set to the time point after 4 hours of operation. The preset initial interval is the reasonable interval in the corresponding relationship table in the aforementioned embodiment.

[0108] Understandably, due to hardware errors in power modules, such as tolerances between different materials used in resonant inductors and capacitors, these errors can significantly impact gain, thus affecting the optimal switching frequency range. Furthermore, inductor failure is a long-term process. Recording the power module's switching frequency during its initial operation and using it as a benchmark for later self-testing allows for different optimal switching frequency ranges for power modules with different hardware, achieving an adaptive effect.

[0109] In short, the probability of resonant inductor failure is low during the initial startup of the power module (e.g., the first 4 hours of operation). Therefore, this embodiment uses the difference between the average switching frequency of the power module during the first 4 hours and the resonant frequency under ideal conditions (i.e., the preset resonant frequency) to correct the reasonable range in the aforementioned correspondence table, thereby further improving the detection accuracy.

[0110] Specifically, before executing the aforementioned self-test process, the power module can first determine whether the current operating time exceeds a preset time point (i.e., a 4-hour time point). If it does not exceed the preset time point, when determining the reasonable range of the switching frequency, it can first calculate the average value of the switching frequency at the previous preset time point, and then, based on the difference between the average value of the switching frequency and the ideal resonant frequency (i.e., the preset resonant frequency), add it to the reasonable range corresponding to the current output voltage in the corresponding relationship table to obtain a new reasonable range. After obtaining the new reasonable range, it can also update the above-mentioned corresponding relationship table for use in subsequent self-test processes.

[0111] If the current running time exceeds the preset time point, the aforementioned self-check process will be entered. During the self-check process, the updated correspondence table can be used to determine the reasonable range.

[0112] To facilitate understanding, the main self-testing method of the resonant inductor in this application embodiment is further illustrated below with a specific example.

[0113] Figure 5 This is a flowchart illustrating a self-testing method for a resonant inductor, as shown in this application. Figure 5 As shown, as an example, the self-testing method for a resonant inductor in this application embodiment may include the following steps:

[0114] Step 510: Calculate the output power and determine whether the output power is greater than the preset power and whether the resonant inductor failure fault is reported. If yes, proceed to step 520; otherwise, proceed to step 590.

[0115] Step 520: Accumulate the input voltage, calculate the switching frequency of the switching module in real time, and determine the reasonable range of the switching frequency.

[0116] Step 530: Determine whether the time during which the switching frequency continuously exceeds the reasonable range has reached the first preset duration. If yes, proceed to step 540; otherwise, clear the switching frequency exceeding flag bit to 0 and proceed to step 550.

[0117] Step 540: The switching frequency exceeds the flag bit of 1, and the average input voltage of the power module within the first preset time period is determined.

[0118] Step 550: Determine whether the switching frequency exceeds the flag bit is 1 and whether the average input voltage is within the preset range. If yes, proceed to step 560; otherwise, proceed to step 570.

[0119] Step 560: The resonant inductor failure flag is set to 1.

[0120] Step 570: Determine if the switching frequency timer is cleared to 0. If yes, proceed to step 580; otherwise, end the process.

[0121] Step 580: When the sum of the input voltages equals 0, the input voltage timer is cleared to 0, and the process ends.

[0122] Step 590: Clear the switching frequency timer to 0, clear the switching frequency exceedance flag to 0, ensure the input voltage sum equals 0, clear the input voltage timer to 0, and end the process.

[0123] The above describes the main detection process for the resonant inductor. To further determine which LLC resonant circuit in the power module has failed, this embodiment also provides a method for determining the reference number of the failed resonant inductor. The following example assumes the power module includes two LLC resonant cavities (i.e.,...). Figure 2 This article will take a specific example to illustrate the detailed process of determining the reference number of a failed resonant inductor.

[0124] Figure 6 This is the second flowchart of the self-test method for the resonant inductor according to an embodiment of this application. For example... Figure 6 As shown, in some embodiments, after determining that the resonant inductor of the resonant module in the power module has failed, the method may further include the following steps:

[0125] Step 610: Obtain the temperature values ​​of the first switching unit and the second switching unit.

[0126] Step 620: Determine the tag number of the failed resonant inductor in the power module based on the temperature values ​​of the first and second switching units.

[0127] Referring to the LLC voltage gain formula in the aforementioned embodiment, it can be understood that although the parameters of the two LLC resonant cavities are inconsistent, the forced current sharing capability of the topology will result in the output power of the two LLC resonant cavities being the same, i.e., the gain on both sides is the same. Therefore, the LLC resonant cavity with abnormal resonant inductance needs to increase its switching frequency to reduce its gain. However, if the two LLC resonant cavities use the same waveform, the switching frequency of the LLC resonant cavity with normal resonant inductance will also increase. This will significantly increase the turn-off loss of the switching transistor in the LLC resonant cavity with normal resonant inductance, leading to a severe imbalance in the heating of the switching transistors of the two full-bridge circuits.

[0128] Based on this, this embodiment utilizes the uneven heating characteristic of the switching transistors in the two LLC resonant cavities. By detecting the temperature of the switching transistors in the switching module, it can determine which LLC resonant inductor in the power module has failed, thus obtaining the tag number of the failed resonant inductor. This allows staff to accurately locate the failed resonant inductor and perform repairs, improving repair efficiency.

[0129] Specifically, the controller can collect the temperature values ​​of the first switching unit and the second switching unit. If the temperature value of the first switching unit is higher than that of the second switching unit, it indicates that the resonant inductor corresponding to the first switching unit is normal, while the resonant inductor corresponding to the second switching unit is faulty. Conversely, if the temperature value of the first switching unit is lower than that of the second switching unit, it indicates that the resonant inductor corresponding to the first switching unit is faulty, while the resonant inductor corresponding to the second switching unit is normal.

[0130] refer to Figure 2 In some embodiments, obtaining the temperature values ​​of the first switch unit and the second switch unit may include obtaining the temperature values ​​of the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the seventh switch, and the eighth switch.

[0131] Figure 7 This is the third flowchart of the self-test method for the resonant inductor according to an embodiment of this application. Figure 7 As shown, in some embodiments, determining the reference number of the failed resonant inductor in the power module based on the temperature values ​​of the first switching unit and the second switching unit may include the following steps:

[0132] Step 710: Take the highest temperature value among the temperature values ​​of the first switch, the second switch, the third switch, and the fourth switch as the first temperature value.

[0133] Step 720: Take the highest temperature value among the temperature values ​​of the fifth, sixth, seventh, and eighth switches as the second temperature value.

[0134] Step 730: Determine the temperature difference between the first temperature value and the second temperature value, and determine the tag number of the failed resonant inductor in the power module based on the temperature difference.

[0135] Specifically, the controller can also collect the temperature values ​​of the first, second, third, and fourth switches in the first switching unit, and find the highest temperature value among these four switches as the first temperature value for calculation. Similarly, the controller collects the temperature values ​​of the fifth, sixth, seventh, and eighth switches in the second switching unit, and finds the highest temperature value among these four switches as the second temperature value for calculation.

[0136] Furthermore, the controller subtracts the first temperature value from the second temperature value to obtain the temperature difference. Finally, the temperature difference is used to determine the reference number of the failed resonant inductor in the power module. It should be noted that if the temperatures of the switching transistors in the first switching unit and the second switching unit are not significantly different, it may be impossible to determine the reference number of the failed resonant inductor based on temperature. Therefore, this embodiment uses the temperature difference to first determine whether the reference number of the failed resonant inductor can be determined by temperature. If yes, the subsequent determination process continues; if not, the main control module of the charging system is directly reported that the reference number of the failed resonant inductor cannot be identified.

[0137] In some implementations, the temperature difference is obtained by subtracting a second temperature value from a first temperature value. Determining the reference number of the failed resonant inductor in the power module based on the temperature difference may include: if the absolute value of the temperature difference is greater than a temperature threshold, and the temperature difference is greater than the temperature threshold, then the reference number of the failed resonant inductor is the resonant inductor reference number of the second resonant unit; if the absolute value of the temperature difference is greater than the temperature threshold, and the temperature difference is less than or equal to the temperature threshold, then the reference number of the failed resonant inductor is the resonant inductor reference number of the first resonant unit.

[0138] Specifically, when the resonant inductor of the power module is determined to be faulty using the aforementioned self-test process, the controller can also collect the temperature values ​​of the first, second, third, and fourth switches in the first switching unit, and find the highest temperature value among these four switches as the first temperature value. The controller then collects the temperature values ​​of the fifth, sixth, seventh, and eighth switches in the second switching unit, and finds the highest temperature value among these four switches as the second temperature value.

[0139] Furthermore, the controller subtracts the second temperature value from the first temperature value to obtain the temperature difference. The controller first determines whether the absolute value of the temperature difference exceeds a temperature threshold. If it does not exceed the temperature threshold, it reports the unidentifiable faulty resonant inductor tag number to the main control module of the charging system. If the absolute value of the temperature difference exceeds the temperature threshold, it then determines whether the temperature difference exceeds the temperature threshold again. If the temperature difference does not exceed the threshold, it reports the failure of the resonant inductor corresponding to the first switching unit (i.e., the first resonant inductor) to the main control module of the charging system; if the temperature difference exceeds the temperature threshold, it reports the failure of the resonant inductor corresponding to the second switching unit (i.e., the second resonant inductor) to the main control module of the charging system.

[0140] This allows for precise location of the faulty resonant inductor's reference number, facilitating subsequent repairs by maintenance personnel.

[0141] Based on the above embodiments, this application also provides a controller. Figure 8 An example of a schematic diagram of the physical structure of a controller is shown, such as... Figure 8 As shown, the controller may include a processor 810, a communication interface 820, a memory 830, and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other through the communication bus 840. The processor 810 can call logic instructions in the memory 830 to execute a self-test method for the resonant inductor. The method includes: when it is determined that the power module meets the preset self-test conditions, continuously determining the switching frequency of the switching module and determining a reasonable range of the switching frequency; if the switching frequency continuously exceeds the reasonable range for a period of time that reaches a first preset duration, determining the average value of the input voltage of the power module within the first preset duration, and determining that the resonant inductor of the resonant module in the power module has failed if the average value of the input voltage is within a preset range.

[0142] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0143] Based on the above embodiments, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the self-testing method for the resonant inductor provided by the above methods. The method includes: when it is determined that the power module meets the preset self-testing conditions, continuously determining the switching frequency of the switching module and determining a reasonable range of the switching frequency; if the switching frequency continuously exceeds the reasonable range for a period of time that reaches a first preset duration, determining the average value of the input voltage of the power module within the first preset duration, and determining that the resonant inductor of the resonant module in the power module has failed when the average value of the input voltage is within a preset range.

[0144] Based on the above embodiments, in another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements a self-testing method for the resonant inductor provided by the above methods. The method includes: when it is determined that the power module meets preset self-testing conditions, continuously determining the switching frequency of the switching module and determining a reasonable range of the switching frequency; if the switching frequency continuously exceeds the reasonable range for a period of time reaching a first preset duration, determining the average value of the input voltage of the power module within the first preset duration, and determining that the resonant inductor of the resonant module in the power module has failed when the average value of the input voltage is within a preset range.

[0145] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0146] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

Claims

1. A self-testing method for a resonant inductor, characterized in that, Applied to a power module, the power module including an AC / DC conversion circuit and a DC / DC conversion circuit, the DC / DC conversion circuit including at least a switching module and a resonant module connected in series in sequence, the method includes: If the power module meets the preset self-test conditions, the switching frequency of the switching module is continuously determined, and a reasonable range of the switching frequency is determined. If the switching frequency continuously exceeds the reasonable range for a period of time that reaches a first preset duration, then the average input voltage of the power module within the first preset duration is determined, and if the average input voltage is within a preset range, then the resonant inductor of the resonant module in the power module is determined to be faulty.

2. The self-testing method for resonant inductors according to claim 1, characterized in that, The preset self-test conditions include that the output power of the power module is greater than the preset power, and that the power module does not report the failure of its resonant inductor.

3. The self-testing method for a resonant inductor according to claim 1, characterized in that, The DC / DC converter circuit further includes a rectifier output module. The switching module includes a first switching unit and a second switching unit. The resonant module includes a first resonant unit and a second resonant unit. The first switching unit is connected in series with the first resonant unit, and the second switching unit is connected in series with the second resonant unit. The rectifier output module is connected to the first resonant unit and the second resonant unit respectively. After determining that the resonant inductor of the resonant module in the power module has failed, the method further includes: Obtain the temperature values ​​of the first switching unit and the second switching unit; The reference number of the failed resonant inductor in the power module is determined based on the temperature values ​​of the first and second switching units.

4. The self-testing method for a resonant inductor according to claim 3, characterized in that, The first switch unit includes a first switch, a second switch, a third switch, and a fourth switch. The first switch and the second switch are connected in series, and the third switch and the fourth switch are connected in parallel across the first switch and the second switch. The second switch unit includes a fifth switch, a sixth switch, a seventh switch, and an eighth switch. The fifth switch and the sixth switch are connected in series, and the seventh switch and the eighth switch are connected in series and then in parallel to the two ends of the fifth switch and the sixth switch. The step of obtaining the temperature values ​​of the first switching unit and the second switching unit includes: The temperature values ​​of the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the seventh switch, and the eighth switch are obtained.

5. The self-testing method for a resonant inductor according to claim 4, characterized in that, The step of determining the reference number of the failed resonant inductor in the power module based on the temperature values ​​of the first and second switching units includes: The highest temperature value among the temperature values ​​of the first switch, the second switch, the third switch, and the fourth switch is taken as the first temperature value; The highest temperature value among the temperature values ​​of the fifth switch, the sixth switch, the seventh switch, and the eighth switch is taken as the second temperature value; The temperature difference between the first temperature value and the second temperature value is determined, and the reference number of the failed resonant inductor in the power module is determined based on the temperature difference.

6. The self-testing method for a resonant inductor according to claim 5, characterized in that, The temperature difference is obtained by subtracting the second temperature value from the first temperature value; The step of determining the reference number of the failed resonant inductor in the power module based on the temperature difference includes: If the absolute value of the temperature difference is greater than the temperature threshold, and the temperature difference is greater than the temperature threshold, then the reference number of the failed resonant inductor is the resonant inductor reference number of the second resonant unit. If the absolute value of the temperature difference is greater than the temperature threshold, and the temperature difference is less than or equal to the temperature threshold, then the reference number of the failed resonant inductor is the resonant inductor reference number of the first resonant unit.

7. The self-testing method for a resonant inductor according to any one of claims 1 to 6, characterized in that, Determining the reasonable range of the switching frequency includes: Based on the average value of the switching frequency within a preset time period, the difference of the preset resonant frequency, and the preset initial interval, a reasonable range of the switching frequency is determined. The preset time period is from the time when the power module starts running to the preset time point, and the preset initial interval is determined based on the output voltage of the power module.

8. The self-testing method for a resonant inductor according to any one of claims 1 to 6, characterized in that, The power module further includes a first sampling unit, a second sampling unit, and a third sampling unit; The first sampling unit is connected in parallel between the two output terminals of the AC / DC conversion circuit, and the first sampling unit is used to collect the input voltage of the power module; The second sampling unit is connected in parallel between the first output terminal and the second output terminal of the DC / DC converter circuit, and the second sampling unit is used to acquire the output voltage of the power module; The third sampling unit is connected in series with the second output terminal of the DC / DC conversion circuit, and the third sampling unit is used to collect the output current of the power module.

9. The self-testing method for a resonant inductor according to any one of claims 4 to 6, characterized in that, The first resonant unit includes a first capacitor, a first resonant inductor, a first transformer, and a second transformer; One end of the first capacitor is connected between the first switch and the second switch, the other end of the first capacitor is connected to one end of the first resonant inductor, the other end of the first resonant inductor is connected to one end of the primary winding of the first transformer, the other end of the primary winding of the first transformer is connected to one end of the primary winding of the second transformer, and the other end of the primary winding of the second transformer is connected between the third switch and the fourth switch. The second resonant unit includes a second capacitor, a second resonant inductor, a third transformer, and a fourth transformer; One end of the second capacitor is connected between the fifth switch and the sixth switch, and the other end of the second capacitor is connected to one end of the second resonant inductor. The other end of the second resonant inductor is connected to one end of the primary winding of the third transformer. The other end of the primary winding of the third transformer is connected to one end of the primary winding of the fourth transformer. The other end of the primary winding of the fourth transformer is connected between the seventh switch and the eighth switch.

10. A charging system, characterized in that, It includes at least two power modules, each power module including a controller for performing a self-test method for a resonant inductor as described in any one of claims 1 to 9.

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