CN114325502A - Method and device for diagnosing pre-charging circuit and power battery system - Google Patents
Method and device for diagnosing pre-charging circuit and power battery system Download PDFInfo
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Abstract
The invention discloses a method and a device for diagnosing a pre-charging circuit and a power battery system. The pre-charging circuit comprises a battery, a current sensor, a main positive contactor, a main negative contactor, a pre-charging resistor, an X capacitor, a whole vehicle load and a main fuse, the pre-charging circuit is provided with three high-voltage sampling points, wherein the first high-voltage sampling point is positioned on a line between the pre-charging contactor and the positive electrode of the battery, the second high-voltage sampling point is positioned on a line between the pre-charging contactor and the whole vehicle load, and the third high-voltage sampling point is positioned on a line between the pre-charging contactor and the pre-charging contactor, and the method comprises the following steps: in the process of electrifying the pre-charging circuit, the voltages of the three high-voltage sampling points are respectively monitored; determining a time point corresponding to the state diagnosis starting of the device in the pre-charging process; and according to the voltages of the three high-voltage sampling points corresponding to the time points, the states of the main positive contactor, the pre-charging contactor and the pre-charging resistor in the pre-charging circuit are diagnosed respectively. The invention solves the technical problem that the fault position of a device in a pre-charging circuit is difficult to accurately position by the traditional diagnosis scheme.
Description
Technical Field
The invention relates to the field of new energy automobiles, in particular to a diagnosis method and device of a pre-charging circuit and a power battery system.
Background
Before the new energy automobile power battery is charged with high voltage, the pre-charging loop needs to be connected firstly, and the X capacitor at the vehicle load end is charged through the pre-charging loop, so that the situation that the high voltage is directly connected and the X capacitor is not charged to cause instant current impact to damage the high-voltage load is prevented. The high-voltage pre-charging circuit mainly comprises a pre-charging resistor and a pre-charging contactor. High voltage contactor, including main contactor and pre-charge contactor, mainly used control high voltage circuit's break-make, in order to guarantee high voltage contactor normal work, avoid the unable closed or contactor electric shock adhesion of contactor to lead to the high pressure accident, power battery generally all carries out necessary diagnosis to the contactor state. Because the two high-voltage devices of the pre-charging resistor and the pre-charging contactor are connected with the main positive contactor in parallel, the current mainstream diagnosis method is to add high-voltage sampling points on two sides of the main positive contactor, and realize the diagnosis of the state of the main positive contactor or the pre-charging contactor and the pre-charging resistor by comparing voltages on the two sides through a cross voltage method.
According to the scheme for diagnosing the main positive contactor and the pre-charging resistor by the cross voltage method, because voltage acquisition points for fault diagnosis are positioned at the front end of the pre-charging contactor and the rear end of the pre-charging resistor, even if the pre-charging contactor branch is determined to have faults through two acquired voltage values, because the pre-charging contactor and the pre-charging resistor are separate high-voltage devices, the fault of the contactor or the damage of the pre-charging resistor cannot be distinguished. The fault position is difficult to pinpoint to traditional scheme promptly, and the maintenance is changed to inconvenient after-sales personnel.
In order to solve the problem that the conventional diagnosis scheme is not easy to accurately locate the fault position of the device in the pre-charging circuit, no effective solution is provided at present.
Disclosure of Invention
The embodiment of the invention provides a method and a device for diagnosing a pre-charging circuit and a power battery system, which are used for at least solving the technical problem that the fault position of a device in the pre-charging circuit is difficult to accurately position by the traditional diagnosis scheme.
According to an aspect of an embodiment of the present invention, there is provided a diagnostic method for a pre-charge circuit, the pre-charge circuit including a battery, a current sensor, a main positive contactor, a main negative contactor, a pre-charge resistor, an X capacitor, a vehicle load, and a main fuse, the pre-charge circuit having three high voltage sampling points, wherein a first high voltage sampling point is located on a line between the pre-charge contactor and a positive electrode of the battery, a second high voltage sampling point is located on a line between the pre-charge resistor and the vehicle load, and a third high voltage sampling point is located on a line between the pre-charge contactor and the pre-charge resistor, the method including: in the process of electrifying the pre-charging circuit, the voltages of the three high-voltage sampling points are respectively monitored; determining a time point corresponding to the state diagnosis starting of the device in the pre-charging process; and diagnosing the states of the main positive contactor, the pre-charging contactor and the pre-charging resistor in the pre-charging circuit respectively according to the voltages of the three high-voltage sampling points corresponding to the time points.
Optionally, determining a time point corresponding to the device state diagnostic turn-on during the precharge process includes: acquiring voltage change trend graphs corresponding to the voltages of the three high-voltage sampling points respectively; and determining a time point corresponding to the state diagnosis starting of the device in the pre-charging process according to the voltage change trend graph.
Optionally, the time point comprises at least one of: the pre-charging contactor control circuit comprises a first time point, a second time point and a third time point, wherein the first time point is a time node before the pre-charging contactor is closed, the second time point is a first preset time node after the pre-charging contactor is closed, the third time point is a second preset time node after the pre-charging contactor is closed, and the first preset time node is earlier than the second preset time node.
Optionally, the diagnosing the device state in the pre-charge circuit according to the voltages of the three high-voltage sampling points corresponding to the time point, where the time point is the first time point, includes: if the voltage of the first high-voltage sampling point is a preset value and the voltages of the second high-voltage sampling point and the third high-voltage sampling point are both in a preset range, determining that the main positive contactor and the pre-charging contactor are in a normal disconnection state; and if the difference value between the voltage of the first high-voltage sampling point and the voltage of the second high-voltage sampling point is smaller than or equal to a first preset voltage difference value, determining that the main positive contactor or the pre-charging contactor has adhesion fault.
Optionally, the diagnosing the states of the main positive contactor, the pre-charging contactor and the pre-charging resistor in the pre-charging circuit according to the voltages of the three high-voltage sampling points corresponding to the time point, where the time point is the second time point, includes: comparing the voltage of the third high voltage sampling point with the voltage of the first high voltage sampling point; when the difference value between the voltage of the third high-voltage sampling point and the voltage of the first high-voltage sampling point is larger than or equal to a second preset voltage difference value, determining that the pre-charging contactor cannot be closed or a driving circuit of the pre-charging contactor has a fault; and when the difference value between the voltage of the third high-voltage sampling point and the voltage of the first high-voltage sampling point is smaller than the second preset voltage difference value, determining that the pre-charging contactor is normally closed.
Optionally, the diagnosing the states of the main positive contactor, the pre-charging contactor and the pre-charging resistor in the pre-charging circuit according to the voltages of the three high-voltage sampling points corresponding to the time point as the third time point includes: comparing the voltage of the second high voltage sampling point with the voltage of the first high voltage sampling point; when the voltage of the second high-voltage sampling point is less than or equal to a preset voltage, determining that the pre-charging resistor is in an abnormal state or the whole vehicle load is in an abnormal state; when the voltage of the second high-voltage sampling point is greater than the preset voltage, determining that the pre-charging resistor is in a normal state; the preset voltage is obtained according to a preset multiple and the voltage of the first high-voltage sampling point.
Optionally, determining that the pre-charging resistor is in an abnormal state or the vehicle load is in an abnormal state includes: acquiring a pre-charge flow of the pre-charge circuit; if the pre-charging current is smaller than a preset current threshold, determining that the pre-charging resistor is in an abnormal state; and if the pre-charging current is greater than or equal to the preset current threshold, determining that the whole vehicle load is in an abnormal state.
According to another aspect of the embodiments of the present invention, there is also provided a diagnostic apparatus of a pre-charging circuit, the pre-charging circuit including a battery, a current sensor, a main positive contactor, a main negative contactor, a pre-charging resistor, an X capacitor, a vehicle load, and a main fuse, the pre-charging circuit having three high voltage sampling points, wherein a first high voltage sampling point is located on a line between the pre-charging contactor and a positive electrode of the battery, a second high voltage sampling point is located on a line between the pre-charging resistor and the vehicle load, and a third high voltage sampling point is located on a line between the pre-charging contactor and the pre-charging resistor, the apparatus including: the monitoring module is used for respectively monitoring the voltages of the three high-voltage sampling points in the process of electrifying the pre-charging circuit; the determining module is used for determining a time point corresponding to the state diagnosis starting of the device in the pre-charging process; and the diagnosis module is used for diagnosing the states of the main positive contactor, the pre-charging contactor and the pre-charging resistor in the pre-charging circuit respectively according to the voltages of the three high-voltage sampling points corresponding to the time points.
According to another aspect of the embodiments of the present invention, there is also provided a power battery system, including a memory and a processor, the memory having a computer program stored therein, the processor being configured to execute the method for diagnosing a pre-charge circuit according to any one of the above items by the computer program.
According to another aspect of the embodiments of the present invention, there is also provided a computer-readable storage medium including a stored program, wherein the program, when executed, controls an apparatus in which the computer-readable storage medium is located to perform the method for diagnosing the pre-charge circuit according to any one of the above.
In the embodiment of the invention, the pre-charging circuit comprises a battery, a current sensor, a main positive contactor, a main negative contactor, a pre-charging resistor, an X capacitor, a finished automobile load and a main fuse, wherein the pre-charging circuit is provided with three high-voltage sampling points, a first high-voltage sampling point is positioned on a line between the pre-charging contactor and the positive electrode of the battery, a second high-voltage sampling point is positioned on a line between the pre-charging contactor and the finished automobile load, a third high-voltage sampling point is positioned on the line between the pre-charging contactor and the pre-charging resistor, and the voltages of the three high-voltage sampling points are respectively monitored in the power-on process of the pre-charging circuit; determining a time point corresponding to the state diagnosis starting of the device in the pre-charging process; according to the voltage of the three high-voltage sampling points corresponding to the time points, the states of a main positive contactor, a pre-charging contactor and a pre-charging resistor in the pre-charging circuit are diagnosed respectively, the additional high-voltage sampling points are added between the pre-charging contactor and the pre-charging resistor, and the state of a device in the pre-charging circuit is diagnosed by utilizing the voltage of the three high-voltage sampling points corresponding to the time points corresponding to the pre-charging contactor, so that the purpose of positioning a fault device is achieved, the device in the pre-charging circuit is accurately distinguished and diagnosed, the technical effect of timely replacing and maintaining the fault device by after-sales personnel is facilitated, and the technical problem that the fault position of the device in the pre-charging circuit is difficult to accurately position by a traditional diagnosis scheme is solved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:
FIG. 1 is a schematic diagram of a pre-charge circuit according to an embodiment of the invention;
FIG. 2 is a flow chart of a method of diagnosing a precharge circuit according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of the voltage variation curves of U1, U2 and U3 during normal precharging according to an embodiment of the present invention;
FIG. 4 is a schematic illustration of a fault diagnosis opportunity according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a diagnostic device for a pre-charge circuit according to an embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Example 1
Fig. 1 is a schematic diagram of a pre-charging circuit according to an embodiment of the present invention, and as shown in fig. 1, the pre-charging circuit includes a battery, a current sensor, a main positive contactor, a main negative contactor, a pre-charging resistor, an X capacitor, a vehicle load, and a main fuse, and the pre-charging circuit has three high-voltage sampling points, where a first high-voltage sampling point is located on a line between the pre-charging contactor and a positive electrode of the battery, a second high-voltage sampling point is located on a line between the pre-charging resistor and the vehicle load, and a third high-voltage sampling point is located on a line between the pre-charging contactor and the pre-charging resistor.
In order to perform the separate diagnosis of the precharge contactor and the precharge resistor, it is necessary to provide the precharge contactor on the side close to the positive electrode of the battery, and the precharge contactor on the side close to the vehicle load. In addition, in addition to the traditional first high-voltage sampling point and the second high-voltage sampling point, an additional third high-voltage sampling point is added between the pre-charging contactor and the pre-charging resistor, and the voltage of the third high-voltage sampling point to the power battery negative pole U01 is monitored in real time during the high-voltage electrifying action.
In accordance with an embodiment of the present invention, there is provided an embodiment of a diagnostic method for a precharge circuit, it being noted that the steps illustrated in the flowchart of the drawings may be performed in a computer system such as a set of computer executable instructions, and that while a logical order is illustrated in the flowchart, in some cases the steps illustrated or described may be performed in an order different than presented herein.
Fig. 2 is a flowchart of a method for diagnosing the precharge circuit according to an embodiment of the present invention, as shown in fig. 2, the method for diagnosing the precharge circuit includes the steps of:
step S202, in the process of electrifying the pre-charging circuit, the voltages of three high-voltage sampling points are respectively monitored;
step S204, determining a time point corresponding to the state diagnosis starting of the device in the pre-charging process;
in an alternative embodiment, determining the time point corresponding to the device state diagnostic turn-on during the precharge process comprises: acquiring voltage change trend graphs corresponding to voltages of the three high-voltage sampling points respectively; and determining a time point corresponding to the diagnosis starting of the device in the pre-charging process according to the voltage variation trend graph. The voltage change trend graphs corresponding to the voltages of the three high-voltage sampling points are all voltage change trend graphs corresponding to the three high-voltage sampling points in the normal power-on process of the pre-charging circuit.
It should be noted that the time points include, but are not limited to, a first time point, a second time point, and a third time point, where the first time point is a time node before the closing of the precharge contactor, the second time point is a first predetermined time node after the closing of the precharge contactor, the third time point is a second predetermined time node after the closing of the precharge contactor, and the first predetermined time node is earlier than the second predetermined time node.
In addition, the first time point is earlier than the second time point, and the second time point is earlier than the third time point.
Step S206, according to the voltages of the three high-voltage sampling points corresponding to the time points, the states of the main positive contactor, the pre-charging contactor and the pre-charging resistor in the pre-charging circuit are diagnosed respectively.
In an alternative embodiment, the diagnosing the device state in the precharge circuit according to the voltages of the three high voltage sampling points corresponding to the time point, where the time point is a first time point, includes: if the voltage of the first high-voltage sampling point is a preset value and the voltages of the second high-voltage sampling point and the third high-voltage sampling point are both within a preset range, determining that the main positive contactor and the pre-charging contactor are in a normal disconnection state; and if the difference value between the voltage of the first high-voltage sampling point and the voltage of the second high-voltage sampling point is smaller than or equal to a first preset voltage difference value, determining that the main positive contactor or the pre-charging contactor has adhesion fault.
It should be noted that the preset range includes 0, where an absolute value of a difference between an endpoint value of the preset range and 0 is between 0.1, and optionally, the preset range is approximately 0.
In an optional embodiment, the time point is a second time point, and the diagnosing the states of the main positive contactor, the pre-charging contactor and the pre-charging resistor in the pre-charging circuit according to the voltages of three high-voltage sampling points corresponding to the time point includes: comparing the voltage of the third high-voltage sampling point with the voltage of the first high-voltage sampling point; when the difference value between the voltage of the third high-voltage sampling point and the voltage of the first high-voltage sampling point is larger than or equal to a second preset voltage difference value, determining that the pre-charging contactor cannot be closed or a driving circuit of the pre-charging contactor fails; and when the difference value between the voltage of the third high-voltage sampling point and the voltage of the first high-voltage sampling point is smaller than a second preset voltage difference value, determining that the pre-charging contactor is normally closed.
In an optional embodiment, the time point is a third time point, and the diagnosing the states of the main positive contactor, the pre-charging contactor and the pre-charging resistor in the pre-charging circuit according to the voltages of three high-voltage sampling points corresponding to the time point includes: comparing the voltage of the second high-voltage sampling point with the voltage of the first high-voltage sampling point; when the voltage of the second high-voltage sampling point is less than or equal to the preset voltage, determining that the pre-charging resistor is in an abnormal state or the load of the whole vehicle is in an abnormal state; when the voltage of the second high-voltage sampling point is greater than the preset voltage, determining that the pre-charging resistor is in a normal state; the preset voltage is obtained according to the preset multiple and the voltage of the first high-voltage sampling point.
It should be noted that, at the closing moment of the pre-charging contactor, the voltage of the third high-voltage sampling point is suddenly changed, the voltage of the second high-voltage sampling point is changed in a curve form by the characteristics of the RC circuit, and the pre-charging contactor fault and the pre-charging resistor fault are distinguished by judging the voltage value at different time points based on different changing trends between the two;
further, in the process of determining that the pre-charging resistor is in an abnormal state or the load of the whole vehicle is in an abnormal state, the pre-charging flow of the pre-charging circuit needs to be acquired; if the pre-charging current is smaller than the preset current threshold, determining that the pre-charging resistor is in an abnormal state; and if the pre-charging current is greater than or equal to the preset current threshold, determining that the load of the whole vehicle is in an abnormal state. By the aid of the method, adverse effects of serious load abnormity of the whole vehicle, such as short-circuit faults, on diagnosis of the faults of the pre-charging resistor can be avoided, and accordingly abnormity of the pre-charging resistor can be judged more accurately.
It should be noted that, during the pre-charging period, when the pre-charging resistor is fused, the representation of the voltage at the second high-voltage sampling point is similar to the short circuit condition of the external load, and needs to be distinguished by the bus current value of the power battery.
Through the steps, the states of the devices in the pre-charging circuit can be diagnosed by adding the additional high-voltage sampling points between the pre-charging contactor and the pre-charging resistor and utilizing the voltages of the three high-voltage sampling points related to the corresponding time points of the pre-charging contactor, so that the purpose of positioning the fault devices is achieved, the devices in the pre-charging circuit can be accurately distinguished and diagnosed, after-sales personnel can conveniently and timely replace and maintain the fault devices, and the technical problem that the fault positions of the devices in the pre-charging circuit cannot be accurately positioned by the traditional diagnosis scheme is solved.
An alternative embodiment of the invention is described in detail below.
In order to realize the fault diagnosis of the pre-charging contactor and the pre-charging resistor, firstly, the assembly sequence of the pre-charging contactor and the pre-charging resistor is ensured, namely the pre-charging contactor is arranged on the side close to the positive pole of the power battery, and the pre-charging resistor is arranged on the side close to the load of the whole vehicle. In addition to the conventional high voltage pick-up points U1 and U2, a high voltage sample point U3 needs to be added between the pre-charge contactor and the pre-charge resistor.
Further, the high-voltage power-on process controlled by the battery management system BMS generally includes: (1) closing the main negative contactor; (2) closing the pre-charging contactor to charge the X capacitor; (3) after the pre-charging is finished, closing the main positive contactor; (4) and (5) disconnecting the pre-charging contactor, and completing high-voltage electrification. The BMS should monitor the voltage of U1, U2, and U3 in real time during the precharge circuit power up against the negative terminal U01 of the battery. Take the power battery voltage U1 as 300V, the pre-charge resistor R as 33ohm, and the X capacitor resistance C as 1000uF as an example. FIG. 3 is a schematic diagram of voltage variation curves of U1, U2 and U3 during normal precharging according to an embodiment of the present invention, as shown in FIG. 3, states of voltage values of U1, U2 and U3 are different at several different characteristic time points according to the above voltage variation curves; fig. 4 is a schematic diagram of a fault diagnosis timing according to an embodiment of the present invention, as shown in fig. 4, 3 characteristic time points, which are T0, T1, and T2, are selected, and are defined as follows: t0: a point in time before the pre-charge contactor is closed; t1: 50ms after the pre-charging contactor is closed; t2: delay 3RC after precharge contactor closing (3 ≈ 33ohm ≈ 1000uF ≈ 100 ms).
Further, according to the voltage variation trend graphs of U1, U2 and U3:
1) at time T0, U1 is 300V, and U3 and U2 are 0V; before T0, U2 and U1 can be compared according to a cross voltage method, if U2 is approximately equal to U1, the main positive contactor or the pre-charging contactor can be considered to have adhesion fault;
2) at time T1, the voltages at the front and rear ends of the precharge resistor, i.e., U2 and U3, are different according to the characteristics of the RC series circuit.
a. If the pre-charging contactor is normally closed, the U3 and the U1 become equal potential points instantly, that is, at the time T1, U3 ═ U1 ═ 300V;
b. u2 is the voltage on both sides of the X capacitor, and the sudden change does not occur, and U2 is 300V (1-e ^ (-t/RC)) according to the calculation formula of the pre-charging voltage, t is 50ms, and U2 is 234V;
in summary, at time T1, by directly comparing the voltages of U3 and U1, it can be determined whether the precharge contactor is malfunctioning:
under the condition a, if U3-U1> -10V (the value can be calibrated according to actual conditions), it can be considered that U3 and U1 are not at equal potentials, that is, the pre-charging contactor has a fault that cannot be closed or the pre-charging contactor driving circuit has a fault;
and b, if U3-U1 is less than 10V (the value can be calibrated according to actual conditions), the U3 and the U1 are considered to be at equal potentials, namely the pre-charging contactor is normally closed.
3) If the precharge contactor is confirmed to be normally closed at time T1, the diagnosis of the precharge resistor can be performed at time T2, the principle is as follows:
substituting t in 100ms according to a precharge voltage calculation formula U2-300V (1-e (-t/RC)), so as to calculate U2-285.5V, wherein the voltage of the capacitor X is about 95% of the total voltage of the power battery; when the pre-charging resistor is fused or semi-fused, the charging time constant RC is increased due to the increase of the equivalent resistor R in the pre-charging circuit, and at the time T2, the voltage value of U2 is smaller than that of the normal case (the semi-fused resistance value of the pre-charging resistor is increased) or is approximately 0 (the pre-charging resistor is completely fused);
further, when U2 ≦ 0.5 × U1, it is considered that the pre-charge resistance is abnormal; condition d, when U2>0.5U1, the pre-charge resistance is considered normal (which may be due to an extended pre-charge time due to a light failure of the vehicle load);
further, according to the above condition c, when the load of the entire vehicle is severely abnormal, i.e., short circuit or equivalent resistance is close to 0, U2< ═ 0.5U1 may also be caused. In this case, the precharge current at time T2 is higher than normal, and when the precharge resistor is blown or semi-blown, the external current is approximately 0, so the above condition c is supplemented, i.e. when U2< >0.5 × U1 and I <1A (the value can be calibrated according to actual conditions), it is determined that the precharge resistor is abnormal.
In the embodiment, the fault that the pre-charging contactor cannot be closed and the pre-charging resistor is melted down can be accurately judged during pre-charging, and after-sales personnel can accurately position and maintain the fault part through positioning diagnosis.
Example 2
According to another aspect of the embodiments of the present invention, there is also provided a diagnostic apparatus of a pre-charge circuit, the pre-charge circuit including a battery, a current sensor, a main positive contactor, a main negative contactor, a pre-charge resistor, an X capacitor, a vehicle load and a main fuse, the pre-charge circuit having three high voltage sampling points, wherein a first high voltage sampling point is located on a line between the pre-charge contactor and a positive electrode of the battery, a second high voltage sampling point is located on a line between the pre-charge resistor and the vehicle load, and a third high voltage sampling point is located on a line between the pre-charge contactor and the pre-charge resistor, fig. 5 is a schematic diagram of the diagnostic apparatus of the pre-charge circuit according to the embodiments of the present invention, as shown in fig. 5, the diagnostic apparatus of the pre-charge circuit including: a monitoring module 52, a determination module 54, and a diagnostic module 56. The diagnostic device of the precharge circuit will be described in detail below.
The monitoring module 52 is used for respectively monitoring the voltages of the three high-voltage sampling points in the process of powering on the pre-charging circuit; a determining module 54, connected to the monitoring module 52, for determining a time point corresponding to the device state diagnosis start-up during the precharge process; and the diagnosis module 56 is connected to the determination module 54, and is configured to diagnose the states of the main positive contactor, the pre-charging contactor, and the pre-charging resistor in the pre-charging circuit according to the voltages of the three high-voltage sampling points corresponding to the time points.
It should be noted that the above modules may be implemented by software or hardware, for example, for the latter, the following may be implemented: the modules can be located in the same processor; and/or the modules are located in different processors in any combination.
In the above embodiment, the diagnosis device of the pre-charging circuit can diagnose the state of the device in the pre-charging circuit by adding an additional high-voltage sampling point between the pre-charging contactor and the pre-charging resistor and using the voltages of the three high-voltage sampling points related to the corresponding time point of the pre-charging contactor, so as to achieve the purpose of positioning the fault device, thereby realizing accurate distinguishing diagnosis of the device in the pre-charging circuit, facilitating the replacement and maintenance of the fault device by after-sales personnel in time, and further solving the technical problem that the fault position of the device in the pre-charging circuit is not easily and accurately positioned by the conventional diagnosis scheme.
It should be noted here that the monitoring module 52, the determining module 54 and the diagnosing module 56 correspond to steps S202 to S206 in embodiment 1, and the modules are the same as the corresponding steps in the implementation example and application scenario, but are not limited to the disclosure of embodiment 1.
Optionally, the determining module 54 includes: the acquisition unit is used for acquiring voltage change trend graphs corresponding to the voltages of the three high-voltage sampling points respectively; and the determining unit is used for determining a time point corresponding to the diagnosis starting of the device state in the pre-charging process according to the voltage change trend graph.
Optionally, the time point includes at least one of: the first time point is a time node before the closing of the pre-charging contactor, the second time point is a first preset time node after the closing of the pre-charging contactor, the third time point is a second preset time node after the closing of the pre-charging contactor, and the first preset time node is earlier than the second preset time node.
Optionally, the time point is a first time point, and the diagnosis module 56 includes: the first diagnosis unit is used for determining that the main positive contactor and the pre-charging contactor are in a normal disconnection state if the voltage of the first high-voltage sampling point is a preset value and the voltages of the second high-voltage sampling point and the third high-voltage sampling point are within a preset range; and the second diagnosis unit is used for determining that the main positive contactor or the pre-charging contactor has adhesion faults if the difference value between the voltage of the first high-voltage sampling point and the voltage of the second high-voltage sampling point is less than or equal to a first preset voltage difference value.
Optionally, the time point is a second time point, and the diagnosis module 56 includes: the first comparison unit is used for comparing the voltage of the third high-voltage sampling point with the voltage of the first high-voltage sampling point; the third diagnosis unit is used for determining that the pre-charging contactor cannot be closed or a driving circuit of the pre-charging contactor has a fault when the difference value between the voltage of the third high-voltage sampling point and the voltage of the first high-voltage sampling point is greater than or equal to a second preset voltage difference value; and the fourth diagnosis unit is used for determining that the pre-charging contactor is normally closed when the difference value between the voltage of the third high-voltage sampling point and the voltage of the first high-voltage sampling point is smaller than the second preset voltage difference value.
Optionally, the time point is a third time point, and the diagnosis module 56 includes: the second comparison unit is used for comparing the voltage of the second high-voltage sampling point with the voltage of the first high-voltage sampling point; the fifth diagnosis unit is used for determining that the pre-charging resistor is in an abnormal state or the load of the whole vehicle is in an abnormal state when the voltage of the second high-voltage sampling point is less than or equal to the preset voltage; the sixth diagnosis unit is used for determining that the pre-charging resistor is in a normal state when the voltage of the second high-voltage sampling point is greater than the preset voltage; the preset voltage is obtained according to the preset multiple and the voltage of the first high-voltage sampling point.
Optionally, the fifth diagnosis unit includes: an acquisition subunit, configured to acquire a pre-charge flow of the pre-charge circuit; the first diagnosis subunit is used for determining that the pre-charging resistor is in an abnormal state if the pre-charging current is smaller than a preset current threshold; and the second diagnosis subunit is used for determining that the load of the whole vehicle is in an abnormal state if the pre-charging current is greater than or equal to the preset current threshold.
Example 3
According to another aspect of the embodiments of the present invention, there is also provided a power battery system, including a memory in which a computer program is stored and a processor configured to execute the method of diagnosing the precharge circuit according to any one of the above-mentioned methods by the computer program.
Example 4
According to another aspect of the embodiments of the present invention, there is also provided a computer-readable storage medium including a stored program, wherein the program, when executed, controls an apparatus in which the computer-readable storage medium is located to perform the method for diagnosing the precharge circuit.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
In the above embodiments of the present invention, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A diagnostic method of a pre-charging circuit, wherein the pre-charging circuit comprises a battery, a current sensor, a main positive contactor, a main negative contactor, a pre-charging resistor, an X capacitor, a vehicle load and a main fuse, the pre-charging circuit has three high voltage sampling points, wherein a first high voltage sampling point is located on a line between the pre-charging contactor and a positive electrode of the battery, a second high voltage sampling point is located on a line between the pre-charging resistor and the vehicle load, and a third high voltage sampling point is located on a line between the pre-charging contactor and the pre-charging resistor, the method comprises:
in the process of electrifying the pre-charging circuit, the voltages of the three high-voltage sampling points are respectively monitored;
determining a time point corresponding to the state diagnosis starting of the device in the pre-charging process;
and diagnosing the states of the main positive contactor, the pre-charging contactor and the pre-charging resistor in the pre-charging circuit respectively according to the voltages of the three high-voltage sampling points corresponding to the time points.
2. The method of claim 1, wherein determining a point in time during the precharge process at which the device state diagnostic is turned on comprises:
acquiring voltage change trend graphs corresponding to the voltages of the three high-voltage sampling points respectively;
and determining a time point corresponding to the state diagnosis starting of the device in the pre-charging process according to the voltage change trend graph.
3. The method of claim 1, wherein the time points comprise at least one of: the pre-charging contactor control circuit comprises a first time point, a second time point and a third time point, wherein the first time point is a time node before the pre-charging contactor is closed, the second time point is a first preset time node after the pre-charging contactor is closed, the third time point is a second preset time node after the pre-charging contactor is closed, and the first preset time node is earlier than the second preset time node.
4. The method according to claim 3, wherein the time point is the first time point, and the diagnosing of the states of the main positive contactor, the pre-charging contactor and the pre-charging resistor in the pre-charging circuit according to the voltages of the three high voltage sampling points corresponding to the time point comprises:
if the voltage of the first high-voltage sampling point is a preset value and the voltages of the second high-voltage sampling point and the third high-voltage sampling point are both in a preset range, determining that the main positive contactor and the pre-charging contactor are in a normal disconnection state;
and if the difference value between the voltage of the first high-voltage sampling point and the voltage of the second high-voltage sampling point is smaller than or equal to a first preset voltage difference value, determining that the main positive contactor or the pre-charging contactor has adhesion fault.
5. The method according to claim 3, wherein the time point is the second time point, and the diagnosing of the states of the main positive contactor, the pre-charging contactor and the pre-charging resistor in the pre-charging circuit according to the voltages of the three high voltage sampling points corresponding to the time point comprises:
comparing the voltage of the third high voltage sampling point with the voltage of the first high voltage sampling point;
when the difference value between the voltage of the third high-voltage sampling point and the voltage of the first high-voltage sampling point is larger than or equal to a second preset voltage difference value, determining that the pre-charging contactor cannot be closed or a driving circuit of the pre-charging contactor has a fault;
and when the difference value between the voltage of the third high-voltage sampling point and the voltage of the first high-voltage sampling point is smaller than the second preset voltage difference value, determining that the pre-charging contactor is normally closed.
6. The method according to claim 3, wherein the time point is the third time point, and the diagnosing of the states of the main positive contactor, the pre-charging contactor and the pre-charging resistor in the pre-charging circuit according to the voltages of the three high voltage sampling points corresponding to the time point comprises:
comparing the voltage of the second high voltage sampling point with the voltage of the first high voltage sampling point;
when the voltage of the second high-voltage sampling point is less than or equal to a preset voltage, determining that the pre-charging resistor is in an abnormal state or the whole vehicle load is in an abnormal state;
when the voltage of the second high-voltage sampling point is greater than the preset voltage, determining that the pre-charging resistor is in a normal state;
the preset voltage is obtained according to a preset multiple and the voltage of the first high-voltage sampling point.
7. The method of claim 6, wherein determining that the pre-charge resistor is in an abnormal state or the vehicle load is in an abnormal state comprises:
acquiring a pre-charge flow of the pre-charge circuit;
if the pre-charging current is smaller than a preset current threshold, determining that the pre-charging resistor is in an abnormal state;
and if the pre-charging current is greater than or equal to the preset current threshold, determining that the whole vehicle load is in an abnormal state.
8. The utility model provides a diagnostic device of pre-charge circuit, its characterized in that, pre-charge circuit includes battery, current sensor, main positive contactor, main negative contactor, pre-charge resistance, X electric capacity, whole car load and main insurance, pre-charge circuit has three high-pressure sampling point, and wherein, first high-pressure sampling point is located pre-charge contactor with on the circuit between the anodal of battery, second high-pressure sampling point is located pre-charge resistance with on the circuit between the whole car load, third high-pressure sampling point is located pre-charge contactor with on the circuit between the pre-charge resistance, the device includes:
the monitoring module is used for respectively monitoring the voltages of the three high-voltage sampling points in the process of electrifying the pre-charging circuit;
the determining module is used for determining a time point corresponding to the state diagnosis starting of the device in the pre-charging process;
and the diagnosis module is used for diagnosing the states of the main positive contactor, the pre-charging contactor and the pre-charging resistor in the pre-charging circuit respectively according to the voltages of the three high-voltage sampling points corresponding to the time points.
9. A power battery system comprising a memory and a processor, characterized in that the memory has stored therein a computer program, the processor being arranged to execute the method of diagnosing a pre-charge circuit according to any of claims 1 to 7 by means of the computer program.
10. A computer-readable storage medium, characterized in that the computer-readable storage medium comprises a stored program, wherein the program, when executed, controls an apparatus in which the computer-readable storage medium is located to perform the method for diagnosing the precharge circuit according to any one of claims 1 to 7.
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