Method for detecting boosting charging abnormity of electric vehicle

Abstract

The invention discloses an electric vehicle boost charging abnormity detection method, and the main conception lies in providing a relatively perfect fault detection measure to monitor the state of each related device in real time during boost charging. By detecting a target output voltage, a charging current, an IGBT temperature, a film capacitor temperature and a motor temperature, signals are collected in a special circuit mode and transmitted to a control device for judgment and decision making; the number of abnormal objects in the boost charging process is judged; if the number is smaller than the number threshold value, executing a boost charging function in a degradation manner within a set time length and / or executing a fault recovery measure for an abnormal object; moreover, if it is detected that the fault of the abnormal object is recovered within the set time length, the recovery measure is stopped after the set time length is reached, and the normal boost charging process continues to be executed. Targeted real-time detection and flexible handling strategies according to the abnormal degree are provided for the boost charging process, and it is effectively ensured that the boost charging function is safe and reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and particularly to a method for detecting abnormal boost charging of an electric vehicle. Background Art

[0002] With the full popularization of pure electric vehicles, the charging needs of users have also changed. Among them, the pursuit of fast charging time and charging safety has become the key factors for consumers to choose pure electric vehicles. At present, major automobile manufacturers have all launched 800V platforms to have faster charging speeds and shorten the charging time. For example, some automobile manufacturers have added a boost charging system to the vehicle to be compatible with 400V / 500V charging piles on the market, raising the voltage to 800V, thereby accelerating the charging speed. However, in this context, the phenomenon of spontaneous combustion still occurs continuously during the charging of electric vehicles.

[0003] Specifically speaking, in the current boost charging system, there are a large number of devices in the working state, including IGBT modules (motor inverter power devices), thin film capacitors, motors (three-phase coils), etc. Almost the entire electric drive system is working during charging. It can be seen that when the vehicle is driving normally, the electric drive system is running, and when boost charging, the electric drive system is also running, which will inevitably affect the entire electric drive system. Conventional charging protection methods are not sufficient to ensure the safety of boost charging and the safety of components of the electric drive system. In particular, through practice, it is found that unexpected abnormal situations will occur during the boost charging system charging. Without a set of reasonable and targeted fault detection measures, it is difficult to ensure the vehicle use safety of users and the safety of vehicle components. Summary of the Invention

[0004] In view of the above, the present invention aims to provide a method for detecting abnormal boost charging of an electric vehicle to solve the problems of damage to components of the electric drive system and safety risks for users caused by the imperfect existing fault detection mechanism during boost charging.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The present invention provides a method for detecting abnormal boost charging of an electric vehicle, which includes:

[0007] After the boost charging function is confirmed to be enabled, respectively obtain the following object electrical signals in real time through a plurality of pre-configured dedicated hardware circuits: target output voltage, charging current, temperature of the motor inverter power device, motor temperature, and thin film capacitor temperature;

[0008] Judge the number of the object electrical signals that appear abnormally during the boost charging process;

[0009] If the quantity is less than a preset threshold, the boost charging function is downgraded and / or a fault recovery measure is performed on the object with an abnormality within a first predetermined duration;

[0010] If it is detected that the fault of the abnormal object has been recovered within the first predetermined duration, after the first predetermined duration arrives, the downgraded charging and / or the fault recovery measure are stopped, and the normal boost charging process is continued.

[0011] In at least one possible implementation manner, after stopping the fault recovery measure and before continuing to perform the normal boost charging function, the abnormality detection method further includes:

[0012] Determine whether the fault recovery holding time of the abnormal object exceeds a preset second predetermined duration;

[0013] If so, continue to perform the normal boost charging process;

[0014] If not, restart the fault recovery measure or trigger a pause in boost charging.

[0015] In at least one possible implementation manner, the acquisition of the motor temperature electrical signal includes: collecting the temperatures of the three-phase windings of the motor during boost charging.

[0016] In at least one possible implementation manner, the abnormality detection method further includes: if it is detected that the number of objects with an abnormality currently is greater than or equal to the preset threshold, or after the first predetermined duration arrives and the fault of the abnormal object has not been recovered, trigger a pause in boost charging.

[0017] In at least one possible implementation manner, the abnormality detection method further includes:

[0018] Before the boost charging function is turned on, confirm that the boost charging enters the preparation state;

[0019] Detect whether there is a fault in the CAN communication signal;

[0020] After determining that the CAN communication signal is normal, turn on the boost charging function;

[0021] If it is determined that the CAN communication signal has a fault, feedback the fault information and wait for the fault to be recovered, and then turn on the boost charging function.

[0022] In at least one possible implementation manner, the abnormality detection method further includes: after the boost charging function is confirmed to be turned on, obtain the battery temperature in real time through the battery management system as the abnormality detection object.

[0023] Compared with the prior art, the main design concept of the present invention is to provide relatively complete fault detection measures to monitor the states of relevant devices in real time during boost charging. Mainly by detecting the target output voltage, charging current, IGBT temperature, thin-film capacitor temperature, motor temperature, etc., the signals are collected in the form of a hardware circuit and transmitted to the control device for judgment and decision-making: judging the number of detected objects with abnormalities during the boost charging process; if it is less than the preset threshold, the boost charging function is degraded and / or fault recovery measures are executed for the objects with abnormalities within the first predetermined time period; if the faults of the abnormal objects are detected to have been recovered within the first predetermined time period, the degraded charging and / or fault recovery measures are stopped after the first predetermined time period arrives, and the normal boost charging process is continued. The present invention proposes a targeted real-time detection strategy for the boost charging process and flexible handling according to the degree of abnormality, effectively ensuring the safety and reliability of the boost charging function. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described below in conjunction with the drawings, where:

[0025] Figure 1 It is a schematic diagram of the method for detecting abnormalities in boost charging of an electric vehicle provided by an embodiment of the present invention;

[0026] Figure 2 It is a topological reference diagram of the output voltage signal acquisition circuit provided by an embodiment of the present invention;

[0027] Figure 3 It is a topological reference diagram of the charging current acquisition circuit provided by an embodiment of the present invention;

[0028] Figure 4 It is a topological reference diagram of the motor inverter power device temperature acquisition circuit provided by an embodiment of the present invention;

[0029] Figure 5 It is a topological reference diagram of the motor temperature acquisition circuit provided by an embodiment of the present invention;

[0030] Figure 6 It is a topological reference diagram of the thin-film capacitor temperature acquisition circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0032] In view of the problems and industry status mentioned above, the following embodiments proposed by the present invention mainly include: a hardware signal acquisition circuit and a fault diagnosis strategy. Among them, the hardware signal acquisition circuit is used to feed back information such as the temperature, voltage, and current of a preset number of detection objects to a DSP (a chip capable of implementing digital signal processing technology), and systematic analysis is performed by a strategy algorithm preset in the DSP to finally determine whether there are faults and abnormalities during boost charging.

[0033] The present invention proposes an embodiment of a method for detecting abnormal boost charging of an electric vehicle. Specifically, as Figure 1 shown, which includes:

[0034] Step S1: After the boost charging function is confirmed to be enabled, respectively obtain the following object electrical signals related to boost charging in real time through a plurality of pre-configured dedicated hardware circuits: target output voltage, charging current, motor inverter power device temperature, motor temperature, and thin film capacitor temperature;

[0035] For the acquisition of the target output voltage among them, reference can be made to Figure 2 the schematic output voltage acquisition circuit shown (only the topological structure of this specific circuit is shown in the figure, and the specific device symbols, selections, etc. involved are not obstacles to understanding and implementation for those skilled in the art). Its main function is to be responsible for acquiring the target output voltage after the boost charging function is enabled, that is, the battery terminal voltage under the boost charging condition. The purpose of setting this detection point is that when an abnormal situation occurs, the spike of the target output voltage may break through the battery insulation layer. Therefore, it is proposed in this embodiment that real-time monitoring is required for early warning protection.

[0036] For the acquisition of the charging current among them, reference can be made to Figure 3 the schematic charging current acquisition circuit shown (only the topological structure of this specific circuit is shown in the figure, and the specific device symbols, selections, etc. involved are not obstacles to understanding and implementation for those skilled in the art). It is mainly responsible for acquiring the magnitude of the current during boost charging and detecting whether the charging current meets the established safety standards, because abnormal current will increase circuit losses, affect the efficiency of boost charging, and may also cause safety hazards in severe cases.

[0037] For the acquisition of the motor inverter power device temperature among them, reference can be made to Figure 4Schematic motor inverter power device temperature acquisition circuit (only the topology of this specific circuit is schematically shown in the figure, and there are no obstacles for those skilled in the art to understand and implement the specific device symbols, selections, etc.). This circuit mainly acquires the temperature change of the switch module (IGBT) during the boost charging process. Since the IGBT switching loss causes heat generation during the boost charging process, high temperature is extremely likely to cause device aging. Therefore, in this embodiment, it is proposed to specifically detect the temperature of the IGBT to ensure the safety of the switch module, and further ensure that the components are not damaged and the charging is safe.

[0038] For the acquisition of the motor temperature, different from directly acquiring the temperature of the motor body and housing, in some embodiments of the present invention, reference can be made to Figure 5 Schematic motor temperature acquisition circuit, which mainly acquires the temperature of the three-phase coils of the motor during the boost charging process (only the topology of this specific circuit is schematically shown in the figure, and there are no obstacles for those skilled in the art to understand and implement the specific device symbols, selections, etc.). Since the three-phase coils of the motor act as inductors during the boost charging process, and continuous energy storage and release will cause a large amount of heat to be generated. When the coil temperature exceeds the limit, it will also pose a hidden danger to the entire boost charging system and users. Therefore, in this embodiment, it is also proposed to perform real-time detection on it.

[0039] For the acquisition of the thin-film capacitor temperature, reference can be made to Figure 6 Schematic thin-film capacitor temperature acquisition circuit (only the topology of this specific circuit is schematically shown in the figure, and there are no obstacles for those skilled in the art to understand and implement the specific device symbols, selections, etc.). This circuit is mainly used to acquire the temperature of the thin-film capacitor during the boost charging process. The thin-film capacitor has the functions of smoothing the input voltage and storing energy. During the boost charging function, the increase in the ripple voltage and the increase in the equivalent series resistance ESR will both cause the capacitor temperature to rise, and then cause the capacitor to fail. And the failure of the capacitor will directly affect the charging efficiency and the instability of the target output voltage during charging, and even trigger the protection shutdown, affecting the boost charging experience and the safety of the charging system.

[0040] It should be added here that the specific object abnormal detection process number executed after starting the boost charging can also include real-time monitoring of the battery temperature, and the measurement of this electrical signal does not require additional dedicated hardware circuits, but the information provided by the battery management system BMS can be directly read.

[0041] Continuing from the previous text, in step S2, determine the number of the abnormal object electrical signals during the boost charging process;

[0042] It is understandable in the art that detecting whether a certain electrical signal is abnormal can be achieved by setting a predetermined safety threshold or other means, and the present invention does not limit or elaborate on this. It should be noted that the design concept of this step is not to adopt the existing technical route in the industry, that is, immediately shutting down the charging function when an abnormality is detected. Instead of directly shutting down the charging, the present invention first examines the number of the aforementioned several specific detection objects with abnormalities occurring currently, and executes different strategies according to the number of objects with abnormalities. This is to balance the function and safety of boost charging.

[0043] Step S3: If the number is less than the preset threshold, then execute boost charging at a reduced level and / or execute a fault recovery measure for the object with an abnormality within the first predetermined time period.

[0044] For example, the number threshold can be set to 3. If the current abnormal objects are two or one, in this condition, the boost charging is not immediately stopped. Instead, a recovery attempt is made from the perspective of overcoming the source (boost charging) that causes the current abnormality. For example, the impact brought by the boost charging is weakened by reducing the charging power by a predetermined ratio; and / or a recovery attempt is made from the perspective of the current abnormality itself (such as a relatively high temperature). For example, when it is detected that the IGBT temperature is higher than the set value, the cooling fan, cooling pipeline, etc. at the IGBT are started to directly relieve the abnormal phenomenon itself first.

[0045] It should be particularly noted here that the aforementioned means are the preliminary disposal measures to balance the uninterrupted boost charging. Therefore, the time consumption of this fault recovery process needs to be restricted. Thus, a first predetermined time period is designed in this link. In actual operation, the first predetermined time period cannot be too long. For example, it can be set to any time period within the range of 30 seconds to 180 seconds.

[0046] Step S4: If it is detected that the fault of the object with an abnormality has been recovered within the first time period, then stop the fault recovery measure after the first time period arrives, and resume the boost charging function to continue executing the normal boost charging process.

[0047] It can be supplemented here that, firstly, in the above embodiment, the conditions for directly triggering the suspension of boost charging are any one of the following: 1. The number of objects with abnormalities detected currently is greater than or equal to the preset threshold; 2. After the first time period arrives, the fault of the object with an abnormality has not been recovered (that is, the electrical signal index has not dropped below the safe value). In this case, it is necessary to give up the charging experience and focus on safety, and execute the corresponding control for shutting off the boost charging relay.

[0048] In addition, after stopping the fault recovery measures and before resuming the normal boost charging function, some other embodiments further include: determining whether the fault recovery holding time of the abnormal object exceeds a preset second predetermined duration. If so, the boost charging function is resumed to continue the normal boost charging process. The concept of this embodiment is to judge the "confidence level" of the abnormal recovery, that is, to examine whether a certain duration (such as 60 seconds to 120 seconds) can be maintained after the fault is eliminated. If the recovery state cannot be maintained and the normal boost charging process is directly entered again, there is a certain possibility of causing problems to recur and charging state fluctuations, etc. Therefore, this can be solved through this embodiment. Of course, it can be understood that if the fault recovery holding time is short, the fault recovery measures can be restarted or the boost charging function can be triggered to pause (turn off the corresponding relay).

[0049] Finally, it can also be supplemented that the abnormal detection method further includes: before the boost charging function is turned on (which can refer to the initial stage of entering the charging process or the stage before resuming after charging is paused), confirming that the boost charging enters the preparation state; then, detecting whether there is a fault in the CAN communication signal; after determining that the CAN communication signal is normal, turning on the boost charging function; if it is determined that the CAN communication signal has a fault, feedback the fault information and wait for the fault to be recovered before turning on the boost charging function. This embodiment is to ensure that the subsequent real-time detection and decision-making tasks can be reliably executed during the boost charging process from the perspective of signal transmission of in-vehicle control devices, detection circuits and other electronic device equipment.

[0050] In summary, the main design concept of the present invention is to provide relatively complete fault detection measures to monitor the states of various related devices in real time during boost charging. Mainly by detecting the target output voltage, charging current, IGBT temperature, thin-film capacitor temperature, motor temperature, etc., the signals are collected in a hardware circuit and transmitted to the control device for judgment and decision-making: judging the number of detected objects that are abnormal during the boost charging process; if it is less than the preset threshold, the boost charging function is degraded and / or the fault recovery measures are executed for the abnormal objects within the first predetermined duration; if it is detected that the faults of the abnormal objects have been recovered within the first predetermined duration, the degraded charging and / or fault recovery measures are stopped after the first predetermined duration arrives, and the normal boost charging process is continued. The present invention proposes a targeted real-time detection strategy for the boost charging process and flexible handling according to the degree of abnormality, effectively ensuring the safety and reliability of the boost charging function.

[0051] In the embodiments of the present invention, if there are any expressions referring to directions, they are relative concepts based on the embodiments. In addition, "at least one" means one or more, and "a plurality of" means two or more. "And / or" describes the relationship between related objects and indicates that there can be three relationships. For example, A and / or B can represent the cases of A existing alone, A and B existing simultaneously, and B existing alone. Here, A and B can be singular or plural. The character " / " generally indicates an "or" relationship between the related objects before and after. "At least one of the following" and its similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0052] The structure, features, and effects of the present invention have been described in detail based on the embodiments shown in the drawings above. However, the above are only the preferred embodiments of the present invention. It should be noted that for the technical features involved in the above embodiments and their preferred modes, those skilled in the art can reasonably combine and match them into a variety of equivalent solutions without departing from and without changing the design concept and technical effects of the present invention. Therefore, the scope of the present invention is not limited by the drawings shown. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified into equivalent changes, should still be within the protection scope of the present invention as long as they do not exceed the spirit covered by the description and the drawings.

Claims

1. A method for detecting abnormal boost charging of an electric vehicle, characterized in that, Including: After the boost charging function is confirmed to be enabled, respectively obtain the following object electrical signals in real time through multiple pre-configured dedicated hardware circuits: target output voltage, charging current, motor inverter power device temperature, motor temperature, and thin film capacitor temperature; Judge the number of abnormal object electrical signals during the boost charging process; If the number is less than a preset threshold, degrade the execution of the boost charging function within the first predetermined duration and / or perform a fault recovery measure for the abnormal object; If it is detected that the faults of the abnormal objects have been recovered within the first predetermined duration, stop the degraded charging and / or fault recovery measures after the first predetermined duration arrives, and continue to execute the normal boost charging process.

2. The method for detecting abnormal boost charging of an electric vehicle according to claim 1, wherein, After stopping the fault recovery measure and before continuing to execute the normal boost charging function, the abnormal detection method further includes: Judge whether the fault recovery holding time of the abnormal object exceeds a preset second predetermined duration; If so, continue to execute the normal boost charging process; If not, restart the fault recovery measure or trigger a boost charging pause.

3. The abnormal boost charging detection method for an electric vehicle according to claim 1, characterized in that, The acquisition of the motor temperature electrical signal includes: collecting the temperature of the three-phase coils of the motor during the boost charging process.

4. The abnormal boost charging detection method for an electric vehicle according to claim 1, characterized in that, The abnormal detection method further includes: if it is detected that the number of currently abnormal objects is greater than or equal to the preset threshold, or after the first predetermined duration arrives, the faults of the abnormal objects have not been recovered, then trigger a boost charging pause.

5. The abnormal boost charging detection method for an electric vehicle according to claim 1, wherein The abnormal detection method further includes: Before the boost charging function is enabled, confirm that the boost charging enters the ready state; Detect whether there is a fault in the CAN communication signal; After determining that the CAN communication signal is normal, enable the boost charging function; If it is determined that the CAN communication signal has a fault, feedback the fault information and wait for the fault to be recovered, and then enable the boost charging function.

6. The abnormal boost charging detection method for an electric vehicle according to any one of claims 1 to 5, characterized in that, The abnormal detection method further includes: after the boost charging function is confirmed to be enabled, obtain the battery temperature in real time through the battery management system as an abnormal detection object.

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