Method for discharging a link capacitor and an automotive system providing the method.

Abstract

The present invention relates to a method for discharging a link capacitor and an automotive system providing the method, wherein the automotive system of the present invention includes a battery, a link capacitor connected in parallel with the battery, an auxiliary discharge circuit including an auxiliary discharge resistor and an auxiliary discharge switch connected in series between the positive and negative electrodes of the battery, and a Battery Management System (BMS) that controls the turning on of the auxiliary discharge switch when the magnitude of the link voltage, which is the voltage across the link capacitor, is greater than or equal to a reference value after the link capacitor has been discharged by a main discharge circuit connected in parallel with the link capacitor.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10 - 2023 - 0104174 filed on August 9, 2023, and all the contents disclosed in the literature of the Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a method for discharging a link capacitor and an automotive system providing the method.

Background Art

[0003] In an automobile driven by the power of a battery such as an electric vehicle (EV, Electric Vehicle), a battery system connecting a load device and a battery may include a battery, a contact part (or relay part), a current sensor, a BMS (Battery Management System) for controlling the battery and the contact part, a link capacitor (DC Link - Cap, X - cap) for smoothing connected in parallel with the battery, and the like.

[0004] The contact part may include a pre - charge contactor, a pre - charge resistor, and a main contactor. First, when the pre - charge contactor is turned on, the link capacitor (X - cap) is charged while the surge current is limited by the pre - charge resistor. Then, when the main contactor is turned on and the pre - charge contactor is turned off, charging or discharging can be performed between the battery and an external device (such as a motor, a charger, etc.).

[0005] During the battery discharge process, the power from the battery is smoothed by the prior accumulation of charge in the link capacitor (X-cap), and this smoothed power is then supplied to external devices (such as motors). This allows the battery system to supply stable power to the load devices. Furthermore, during the battery charging process, the link capacitor (X-cap) smooths the power from external devices (such as chargers), and this smoothed power can then be supplied to the battery.

[0006] On the other hand, if the contactor fails, the electrical connection between the battery and external devices cannot be properly controlled. Examples of physical contactor failures include a stack-close failure, where the contactor welds while closed, or a stack-open failure, where the contactor welds while open.

[0007] In relation to contactor fault diagnosis, conventional methods have involved measuring the voltage across the battery and the voltage across the link capacitor (X-cap) when the contactor is ON, calculating the difference between the battery voltage and the link capacitor voltage, and comparing the calculated difference with the error value.

[0008] In addition to precise contactor fault diagnosis, the residual charge in the link capacitor (DC Link-Cap) must be discharged by the discharge circuit on the Charyan side in various situations such as car collisions.

[0009] If the link capacitor (DC Link-Cap) does not discharge sufficiently, it can lead to misdiagnosis in contactor fault diagnosis and various problems during the vehicle maintenance process. [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The present invention relates to a method for discharging a link capacitor that can discharge the link capacitor even in emergency situations such as when the discharge circuit on the charger side malfunctions, and to a battery system that provides this method for automobiles. [Means for solving the problem]

[0011] An automotive system according to one feature of the present invention includes a battery, a link capacitor connected in parallel with the battery, an auxiliary discharge circuit including an auxiliary discharge resistor and an auxiliary discharge switch connected in series between the positive and negative electrodes of the battery, and a Battery Management System (BMS) that controls the turn-on of the auxiliary discharge switch when the magnitude of the link voltage, which is the voltage across the link capacitor, is greater than or equal to a reference value after the link capacitor has been discharged by a main discharge circuit connected in parallel with the link capacitor.

[0012] The automotive system may further include the main discharge circuit, which includes a main discharge resistor and a main discharge switch connected in series between the positive and negative electrodes of the battery.

[0013] The automotive system may further include a higher-level controller that controls the main discharge switch to turn on when an emergency event occurs, and after the main discharge switch has been controlled, if the magnitude of the link voltage is greater than or equal to the reference value, instructs the BMS to control the auxiliary discharge switch to turn on.

[0014] The automotive system further includes a main contactor connected between the positive electrode of the battery and one end of the link capacitor, and the BMS can control the turn-off of the main contactor when the emergency event occurs.

[0015] The automotive system may further include a battery system comprising the battery, the main contactor, the auxiliary discharge circuit, and the BMS.

[0016] The BMS can generate a first fault alarm message including fault status information for the main discharge circuit and a second fault alarm message including fault status information for the auxiliary discharge circuit if the magnitude of the link voltage is greater than or equal to the reference value after the auxiliary discharge switch has been turned on.

[0017] The BMS can generate a first fault alarm message, including fault status information of the main discharge circuit, if the magnitude of the link voltage is less than the reference value after the auxiliary discharge switch has been turned on.

[0018] The BMS can diagnose a fusion failure in the main contactor if, after the auxiliary discharge switch has been turned on, the magnitude of the link voltage is less than the reference value.

[0019] The BMS can diagnose a fusion failure in the main contactor by calculating the difference between the magnitude of the battery voltage, which is the voltage across the battery, and the magnitude of the link voltage, and by comparing the difference with a predetermined error value.

[0020] Another feature of the present invention is a method for discharging a link capacitor in an automotive system that includes a main discharge circuit including a main discharge resistor and a main discharge switch connected in series between the positive and negative electrodes of a battery, and an auxiliary discharge circuit including an auxiliary discharge resistor and an auxiliary discharge switch connected in series between the positive and negative electrodes of the battery, wherein the method discharges a link capacitor connected in parallel with the battery, and when an emergency event occurs, the BMS (Battery Management System) is instructed by a higher-level controller to discharge the link capacitor. The BMS includes the steps of: the BMS turning off a main contactor connected between the positive electrode of the battery and one end of the link capacitor; the higher-level controller turning on the main discharge switch; the higher-level controller determining whether the magnitude of the link voltage is less than a reference value after the main discharge switch has been controlled; if the determination result is that the magnitude of the link voltage is greater than or equal to the reference value, the BMS turning on the auxiliary discharge switch; the BMS determining whether the magnitude of the link voltage is less than the reference value after the auxiliary discharge switch has been controlled; and if the determination result is that the magnitude of the link voltage is less than the reference value, the BMS diagnosing a fusion failure of the main contactor.

[0021] The method for discharging the link capacitor may further include the step of determining whether the magnitude of the link voltage is less than the reference value after the auxiliary discharge switch has been controlled, and if the determination result indicates that the magnitude of the link voltage is equal to or greater than the reference value, the BMS generates a first fault alarm message including fault status information of the main discharge circuit and a second fault alarm message including fault status information of the auxiliary discharge circuit.

[0022] The method for discharging the link capacitor may further include, before the step of diagnosing the fusion failure of the main contactor, after the auxiliary discharge switch is controlled, when the magnitude of the link voltage is less than the reference value, the BMS generating a first failure alarm message including the failure state information of the main discharge circuit.

[0023] The step of diagnosing the fusion failure of the main contactor may be that the BMS calculates the difference value between the magnitude of the battery voltage, which is the voltage across both ends of the battery, and the magnitude of the link voltage, and compares the difference value with a predetermined error value to diagnose the fusion failure of the main contactor.

Advantages of the Invention

[0024] According to an embodiment of the present invention, even when the main discharge circuit on the vehicle side cannot perform its original function, the auxiliary discharge circuit on the battery system side can sufficiently discharge the link capacitor (DC Link-Cap, X-cap).

[0025] According to an embodiment of the present invention, by precisely diagnosing the stuck open fault of the contactor, the cost of replacing normal contactors due to misdiagnosis can be saved, and the cause of the defect when a defect occurs in the battery system can be quickly detected.

[0026] According to an embodiment of the present invention, in an emergency situation such as a vehicle collision, the link capacitor (DC Link-Cap, X-cap) can be sufficiently discharged, ensuring the safety of the vehicle maintenance workers, and quickly providing the cause of the vehicle problem to the workers in vehicle maintenance. <000……此处原文似乎不完整,推测可能是 的完整内容,翻译为

Brief Description of the Drawings

[0027] ......此处原文似乎不完整,推测可能是

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[0027] ......此处原文似乎不完整,推测可能是 的完整内容,翻译为 [Figure 1] ......此处原文似乎不完整,推测可能是 [Figure 1] 的完整内容,翻译为 [Figure 1] It is a block diagram illustrating an automotive system according to an embodiment. ......此处原文似乎不完整,推测可能是 的完整内容,翻译为 [Figure 2] ......此处原文似乎不完整,推测可能是 [Figure 2] 的完整内容,翻译为 [Figure 2] It is a circuit diagram for explaining FIG. 1 in detail. ......此处原文似乎不完整,推测可能是 的完整内容,翻译为 [Figure 3] ......此处原文似乎不完整,推测可能是 [Figure 3] 的完整内容,翻译为 [Figure 3]This diagram illustrates the functions of the main discharge circuit and auxiliary discharge circuit according to one embodiment. [Figure 4] This is a flowchart illustrating a method for discharging a link capacitor according to one embodiment. [Modes for carrying out the invention]

[0028] The embodiments disclosed herein will be described in detail below with reference to the attached drawings, but identical or similar components will be assigned the same or similar drawing numbers, and redundant descriptions thereof will be omitted. The suffixes “module” and / or “part” used for components in the following description are added or used interchangeably solely for the convenience of drafting the specification and do not have any distinguishing meaning or role in themselves. Furthermore, in describing the embodiments disclosed herein, if it is determined that a specific description of the relevant prior art would obscure the gist of the embodiments disclosed herein, such detailed description will be omitted. In addition, the attached drawings are provided to facilitate the understanding of the embodiments disclosed herein, and it should be understood that the attached drawings do not limit the technical ideas disclosed herein and include all modifications, equivalents or substitutes that fall within the concept and scope of the invention.

[0029] Terms including ordinal numbers such as "first," "second," etc., can be used to describe various components, but the components are not limited by such terms. These terms are used solely for the purpose of distinguishing one component from another.

[0030] When it is stated that one component is “connected” or “linked” to another component, it should be understood that this may mean that the other component is directly connected or linked to it, or that there may be other components in between. On the other hand, when it is stated that one component is “directly connected” or “directly linked” to another component, it should be understood that there are no other components in between.

[0031] In this application, terms such as “includes” or “having” should be understood to indicate the presence of features, figures, steps, actions, components, parts, or combinations thereof as described in the specification, and not to preemptively exclude the possibility of the presence or addition of one or more other features, figures, steps, actions, components, parts, or combinations thereof.

[0032] Figure 1 is a block diagram illustrating an automotive system according to one embodiment, Figure 2 is a circuit diagram illustrating Figure 1 in detail, and Figure 3 is a diagram illustrating the functions of the main discharge circuit and auxiliary discharge circuit according to one embodiment.

[0033] Referring to Figure 1, the automobile system 10 includes a battery system 100, a load device 200, and a higher-level controller 300.

[0034] Referring to Figures 1 and 2, the battery system 100 includes a battery 110, a Battery Management System (BMS) 120, an auxiliary discharge circuit 130, and a positive electrode main contactor (POS_Rely). In some embodiments, the battery system 100 may further include a negative electrode main contactor (NEG_Rely), a pre-charge contactor (Pre_Rely), and a pre-charge resistor (Pre_Res).

[0035] In Figures 1 to 3, a battery 110 is connected between the two output terminals (OUT1 and OUT2) of the battery system 100. A positive terminal main contactor (POS_Rely) is connected between the positive terminal of the battery 110 and the first output terminal (OUT1), and a negative terminal main contactor (NEG_Rely) is connected between the negative terminal of the battery 110 and the second output terminal (OUT2). The configuration and the connections between the configurations shown in Figure 1 are just one example, and the invention is not limited thereto.

[0036] The battery 110 may include multiple battery cells electrically connected in series and parallel. In one embodiment, the battery cells may be rechargeable secondary batteries. For example, in discharge mode, the battery 110 can supply power to the load device 200.

[0037] The BMS120 can control the entire battery system 100. In one embodiment, when an emergency event occurs, the BMS120 can control the auxiliary discharge circuit 130 to discharge the link capacitors (DC Link-Cap, X-cap).

[0038] The auxiliary discharge circuit 130 may include an auxiliary discharge resistor (Dis_Res2) and an auxiliary discharge switch (Dis_SW2).

[0039] Referring to Figure 2, the auxiliary discharge resistor (Dis_Res2) and the auxiliary discharge switch (Dis_SW2) can be connected in series between the positive and negative terminals of the battery 110. For example, the magnitude of the auxiliary discharge resistor (Dis_Res2) can be set in various ways depending on the experiment.

[0040] When the positive main contactor (POS_Rely) and the negative main contactor (NEG_Rely) are turned on, the battery system 100 and the load device 200 are electrically connected. This allows power from the battery 110 to be supplied to the load device 200, enabling the automotive system 10 to perform its pre-set operations. The main contactor can be instructed to include a positive main contactor (POS_Rely) and a negative main contactor (NEG_Rely).

[0041] The pre-charge resistor (Pre_Res) and pre-charge contactor (Pre_Rely) can be connected in series between the positive terminal of the battery 110 and the first output terminal (OUT1). The pre-charge resistor (Pre_Res) and pre-charge contactor (Pre_Rely) can also be connected in series between one end and the other end of the positive terminal main contactor (POS_Rely).

[0042] The pre-charge contactor (Pre_Rely) reduces the surge current generated when the positive terminal main contactor (POS_Rely) is connected to the load device 200, thereby preventing damage to the positive terminal main contactor (POS_Rely) and the battery 110.

[0043] The pre-charge contactor (Pre_Rely) can perform free-charging. Specifically, when the pre-charge contactor (Pre_Rely) is turned on, the link capacitor (X-cap) receives a small current reduced by the pre-charge resistor (Pre_Res) and can gradually accumulate charge. Subsequently, the positive electrode main contactor (POS_Rely) is turned on, and after a predetermined time has elapsed with both the pre-charge contactor (Pre_Rely) and the positive electrode main contactor (POS_Rely) turned on, the pre-charge contactor (Pre_Rely) can be turned off. This reduces the surge current when the positive electrode main contactor (POS_Rely) is connected to the load device 200.

[0044] The positive terminal main contactor (POS_Rely) can be connected between the positive terminal of the battery 110 and the load device 200. Referring to Figure 1, the positive terminal main contactor (POS_Rely) can be connected in parallel with the precharge resistor (Pre_Res) and the precharge contactor (Pre_Rely). When the positive terminal main contactor (POS_Rely) is turned on, the battery 110 and the load device 200 are electrically connected, and the battery 110 can be charged or discharged.

[0045] The load device 200 may be a device that receives power from the battery system 100 and drives the automobile system 10.

[0046] Referring to Figure 2, the load device 200 includes a motor 210, an inverter 220, and a main discharge circuit 230. In some embodiments, the load device 200 may further include a link capacitor (X-cap), a plurality of Y-capacitors (Y-cap_1, Y-cap_2), and a plurality of load resistors (Y-Res_1, Y-Res_2). Although Figures 2 and 3 show the link capacitor (X-cap) being included in the load device 200, the link capacitor (X-cap) may be included in the battery system 100, but is not limited to this.

[0047] The motor 210 may be a device that converts electrical energy into rotational kinetic energy. The inverter 220 can convert the DC current supplied by the battery 110 into AC current and supply it to the motor 210. Since the motor 210, inverter 220, etc. are already widely known components, a detailed explanation will be omitted below.

[0048] The main discharge circuit 230 may include a main discharge resistor (Dis_Res1) and a main discharge switch (Dis_SW1). Referring to Figure 2, the main discharge resistor (Dis_Res1) and the main discharge switch (Dis_SW1) may be connected in series between the ends of the inverter 220. The main discharge resistor (Dis_Res1) and the main discharge switch (Dis_SW1) may be connected in series between the first output terminal (OUT1) and the second output terminal (OUT2) of the battery system 100.

[0049] In this embodiment, if an emergency event occurs while the vehicle system 10 is in operation, the BMS 12 controls the main contactors (POS_Rely, NEG_Rely) to turn off. For example, an emergency event may include an event such as the vehicle system 10 colliding with an external vehicle system. In an emergency event situation, to prevent secondary accidents such as battery 110 ignition, the higher-level controller 300 transmits the occurrence of the emergency event to the BMS 12, and the BMS 12 can control the main contactors (POS_Rely, NEG_Rely) to turn off.

[0050] Next, in the event of an emergency, a safety assessment of the entire vehicle system 10 and / or the entire battery system 100 is required. For this reason, it is important to proactively discharge the link capacitor (X-cap) as quickly as possible.

[0051] For example, in the event of a physical failure such as a stack-close failure where the main contactors (POS_Rely, NEG_Rely) are welded in a closed state, or a stack-open failure where the main contactors (POS_Rely, NEG_Rely) are welded in an open state, the main contactors (POS_Rely, NEG_Rely) may not be turned off by the BMS12 control. In some embodiments, when an emergency event occurs, a safety diagnosis may be performed to determine whether the main contactors (POS_Rely, NEG_Rely) are properly turned off. At this time, if a fault diagnosis of the main contactors (POS_Rely, NEG_Rely) is performed while the charge stored in the link capacitor (X-cap) has not been fully discharged, a misdiagnosis may occur. Below, Figure 4 describes in detail how to discharge the link capacitor (DC Link-Cap, X-cap) when an emergency event occurs.

[0052] A link capacitor (DC Link-Cap, X-cap) can be a smoothing capacitor (DC_Link Capacitor). For example, a link capacitor (X-cap) can function as a buffer between the battery 110 and the inverter 220, preventing large voltage differences from occurring between the battery 110 and the inverter 220.

[0053] Multiple Y-capacitors (Y-cap_1, Y-cap_2) can include a first Y-capacitor (Y-cap_1) and a second Y-capacitor (Y-cap_1). The first Y-capacitor (Y-cap_1) and the second Y-capacitor (Y-cap_1) can be connected in series between the (+) and (-) ends of the load-side link. The node between the first Y-capacitor (Y-cap_1) and the second Y-capacitor (Y-cap_1) can be connected to ground. Multiple load resistors (Y-Res_1, Y-Res_2) can include a first load resistor (Y-Res_1) and a second load resistor (Y-Res_2). The first load resistor (Y-Res_1) and the second load resistor (Y-Res_2) can be connected in series between the (+) and (-) ends of the load-side link. The node between the first load resistor (Y-Res_1) and the second load resistor (Y-Res_2) can be connected to ground. Multiple Y-capacitors (Y-cap_1, Y-cap_2) and multiple load resistors (Y-Res_1, Y-Res_2) are components widely used in existing automotive systems, and a detailed explanation of them is omitted.

[0054] The higher-level controller 300 can control the entire vehicle system 10. The higher-level controller 300 can communicate with the BMS 120 and monitor the status of the battery system 100. The higher-level controller 300 can control the battery system 100 through the BMS 120.

[0055] In this embodiment, when an emergency event occurs, the higher-level controller 300 can turn off the main contactors (POS_Rely, NEG_Rely) via the BMS 120. The higher-level controller 300 can also directly turn on the main discharge switch (Dis_SW1) of the main discharge circuit 230, thereby discharging the link capacitor (X-cap). Furthermore, the higher-level controller 300 can control the BMS 120 to turn on the auxiliary discharge switch (Dis_SW2) of the auxiliary discharge circuit 130.

[0056] Referring to Figure 3, first, when the main discharge switch (Dis_SW1) of the main discharge circuit 230 is turned on by the control of the higher-level controller 300, the charge stored in the link capacitor (X-cap) can be consumed through the main discharge resistor (Dis_Res1) (direction 1). If the link capacitor (X-cap) is not sufficiently discharged by the main discharge circuit 230, the auxiliary discharge switch (Dis_SW2) of the auxiliary discharge circuit 130 can be turned on by the control of the BMS 120. In this case, the charge stored in the link capacitor (X-cap) can be consumed through the auxiliary discharge resistor (Dis_Res2) (direction 2).

[0057] According to the embodiment, the link capacitor (X-cap) can be fully discharged to the desired target through the main discharge circuit 230 and the auxiliary discharge circuit 130, thereby preventing misdiagnosis problems when performing various safety diagnoses.

[0058] Figure 4 is a flowchart illustrating a method for discharging a link capacitor according to one embodiment.

[0059] Referring to Figure 4, when an emergency event occurs, the BMS12 controls the turn-off of the main contactors (POS_Rely, NEG_Rely) (S110, S120).

[0060] An emergency event may include the occurrence of an emergency situation that threatens the safety of the vehicle system 10, such as a collision with an external object or a malfunction of the vehicle system 10. For example, an emergency event may include various events that require the main contactor (POS_Rely, NEG_Rely) to be turned off.

[0061] The higher-level controller 300 can determine when an emergency event occurs corresponding to a preset situation, and when an emergency event occurs, it can transmit the emergency event to the BMS 12. The BMS 12 can then turn off the main contactors (POS_Rely, NEG_Rely).

[0062] Under normal conditions, the main contactors (POS_Rely, NEG_Rely) can perform normal turn-off switching operations under the control of the BMS12. However, in the event of physical failures such as stack-close and stack-open, the main contactors (POS_Rely, NEG_Rely) may not be able to perform physical turn-off switching even if they receive a turn-off control signal from the BMS12. In other words, when an emergency event occurs, the main contactors (POS_Rely, NEG_Rely) should be turned off, but a problem arises where they cannot be turned off. Therefore, after transmitting the turn-off control signal, it is necessary to diagnose whether the main contactors (POS_Rely, NEG_Rely) have actually been turned off and to check the status of the main contactors (POS_Rely, NEG_Rely).

[0063] Next, the higher-level controller 300 controls the turn-on of the main discharge switch (Dis_SW1) of the main discharge circuit 230 mounted on the load device 200 (S130).

[0064] Fusion fault diagnosis of the main contactor (POS_Rely, NEG_Rely) can be performed by calculating the difference between the magnitude of the battery voltage, which is the voltage across the battery 110, and the magnitude of the link voltage, which is the voltage across the link capacitor (X-cap), and comparing this difference with a predetermined error value. Therefore, if the link capacitor (X-cap) is not sufficiently discharged, the fusion fault diagnosis for the main contactor (POS_Rely, NEG_Rely) may be inaccurate. In this embodiment, the higher-level controller 300 controls the turn-on of the main discharge switch (Dis_SW1) of the main discharge circuit 230. Then, the charge stored in the link capacitor (X-cap) can be consumed through the main discharge resistor (Dis_Res1).

[0065] Next, the higher-level controller 300 determines whether the magnitude of the link voltage, which is the voltage across the link capacitor (X-cap), is below a reference value (S140).

[0066] The higher-level controller 300 can receive the magnitude of the link voltage from a voltage device (not shown) that measures the voltage across the link capacitor (X-cap).

[0067] For example, the reference value can correspond to a voltage value that includes a predetermined error value at ground level. When the link capacitor (X-cap) is sufficiently discharged, the magnitude of the link voltage can correspond to ground level. If the magnitude of the link voltage is greater than or equal to the reference value, the main discharge circuit 230 can indicate that the link capacitor (X-cap) is not sufficiently discharged. Therefore, if the magnitude of the link voltage is greater than or equal to the reference value, it can indicate a fault condition in the main discharge circuit 230.

[0068] Next, if the magnitude of the link voltage is below the reference value (S140, YES), the BMS12 diagnoses a fusion fault in the main contactor (POS_Rely, NEG_Rely) (S150).

[0069] For example, if the magnitude of the link voltage is below a reference value, the higher-level controller 300 can instruct the BMS 12 to perform a fusion fault diagnosis of the main contactors (POS_Rely, NEG_Rely).

[0070] The BMS12 can receive the magnitude of the battery voltage from a voltage device (not shown) that measures the voltage across the battery 110. The BMS12 can also receive the magnitude of the link voltage from a voltage device (not shown) that measures the voltage across the link capacitor (X-cap). For example, if the link capacitor (X-cap) is mounted on the battery system 100, the BMS12 can receive the magnitude of the link voltage directly from the voltage device. As another example, if the link capacitor (X-cap) is mounted on the load device 200, the BMS12 can receive the magnitude of the link voltage through the higher-level controller 300.

[0071] The BMS12 calculates the difference between the magnitude of the battery voltage and the magnitude of the link voltage. For example, if the difference is greater than or equal to a predetermined error value, the BMS12 can diagnose that the main contactors (POS_Rely, NEG_Rely) have successfully turned off in response to the turn-off control signal. As another example, if the difference is less than a predetermined error value, the BMS12 can diagnose that the main contactors (POS_Rely, NEG_Rely) are in a stack-close fault condition where they are welded in a closed state.

[0072] Next, if the magnitude of the link voltage is greater than or equal to the reference value (S140, NO), the BMS12 controls the turn-on of the auxiliary discharge switch (Dis_SW2) of the auxiliary discharge circuit 130 mounted on the battery system 100 (S160).

[0073] For example, the higher-level controller 300 can instruct the BMS 12 to turn on the auxiliary discharge switch (Dis_SW2) of the auxiliary discharge circuit 130. Subsequently, the charge stored in the link capacitor (X-cap) can be consumed through the auxiliary discharge resistor (Dis_Res2). In this embodiment, if the link capacitor (X-cap) is not sufficiently discharged by the main discharge circuit 230, the auxiliary discharge circuit 130 can be used to discharge the link capacitor (X-cap) additionally.

[0074] Next, the BMS12 determines whether the magnitude of the link voltage, which is the voltage across the link capacitor (X-cap), is below a reference value (S170).

[0075] The BMS12 can receive the magnitude of the link voltage from a voltage device (not shown) that measures the voltage across the link capacitor (X-cap). For example, if the link capacitor (X-cap) is mounted on the battery system 100, the BMS12 can receive the magnitude of the link voltage directly from the voltage device. In another example, if the link capacitor (X-cap) is mounted on the load device 200, the BMS12 can receive the magnitude of the link voltage through the higher-level controller 300.

[0076] Next, if the magnitude of the link voltage is below the reference value (S170, YES), the BMS12 generates a fault signal message for the main discharge circuit 230 and diagnoses a fusion fault in the main contactor (POS_Rely, NEG_Rely) (S150, S180).

[0077] The S180 step, which generates a first fault signal message containing information about the fault state of the main discharge circuit 230, is not limited to occurring after the S170 step. In other embodiments, the S180 step may occur after the S140 step. Also, the step for diagnosing fusion faults of the main contactors (POS_Rely, NEG_Rely) that proceeds after the S180 step may be the same step for diagnosing fusion faults of the main contactors (POS_Rely, NEG_Rely) that proceeds after the S140 step. A detailed explanation of this is omitted.

[0078] For example, when the BMS12 transmits information to the higher-level controller 300 indicating that the magnitude of the link voltage is below a reference value, the higher-level controller 300 can generate a first fault signal message and display it to the user.

[0079] As another example, the BMS12 generates a first fault signal message containing information about the fault condition of the main discharge circuit 230 and transmits it to the higher-level controller 300, which can then display the first fault signal message to the user.

[0080] Next, if the magnitude of the link voltage is greater than or equal to a reference value (S170, NO), the BMS12 generates a first fault signal message containing information about the fault condition of the main discharge circuit 230 and a second fault signal message containing information about the fault condition of the auxiliary discharge circuit 130 (S190).

[0081] The S190 step, which generates a first fault signal message containing information about the fault state of the main discharge circuit 230, is not limited to occurring after the S170 step. In other embodiments, the step of generating the first fault signal message in the S190 step may occur after the S140 step. In this case, the BMS 12 may generate only a second fault signal message in the S190 step and transmit the second fault signal message to the higher-level controller 300.

[0082] The higher-level controller 300 can display the first and second fault signal messages to the user. Also, because the link capacitor (X-cap) is not sufficiently discharged, the BMS 12 may not diagnose fusion faults in the main contactors (POS_Rely, NEG_Rely).

[0083] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by persons with ordinary skill in the art to which the present invention belongs also fall within the scope of the present invention.

Claims

1. Battery and A link capacitor connected in parallel with the aforementioned battery, An auxiliary discharge circuit including an auxiliary discharge resistor and an auxiliary discharge switch connected in series between the positive and negative terminals of the battery, An automotive system comprising a BMS that controls the turn-on of an auxiliary discharge switch when, after the link capacitor has been discharged by a main discharge circuit connected in parallel with the link capacitor, the magnitude of the link voltage, which is the voltage across the link capacitor, is greater than or equal to a reference value.

2. The automotive system according to claim 1, further comprising the main discharge circuit, which includes a main discharge resistor and a main discharge switch connected in series between the positive and negative electrodes of the battery.

3. When an emergency event occurs, the higher-level controller controls the main discharge switch to turn on, and after the main discharge switch has been controlled, if the magnitude of the link voltage is greater than or equal to the reference value, it instructs the BMS to control the auxiliary discharge switch to turn on. The automobile system according to claim 2, further comprising:

4. The system further includes a main contactor connected between the positive terminal of the battery and one end of the link capacitor, The aforementioned BMS is The automobile system according to claim 3, wherein the main contactor is turned off when the aforementioned emergency event occurs.

5. The automotive system according to claim 4, further comprising a battery system including the battery, the main contactor, the auxiliary discharge circuit, and the BMS.

6. The aforementioned BMS is The automotive system according to claim 4 or 5, wherein, after the auxiliary discharge switch is turned on, if the magnitude of the link voltage is greater than or equal to the reference value, a first fault alarm message including fault state information of the main discharge circuit and a second fault alarm message including fault state information of the auxiliary discharge circuit are generated.

7. The aforementioned BMS is The automotive system according to claim 4 or 5, wherein, after the auxiliary discharge switch has been turned on, if the magnitude of the link voltage is less than the reference value, a first fault alarm message including fault state information of the main discharge circuit is generated.

8. The aforementioned BMS is The automotive system according to claim 4 or 5, wherein, after the auxiliary discharge switch has been turned on, if the magnitude of the link voltage is less than the reference value, a fusion failure of the main contactor is diagnosed.

9. The aforementioned BMS is The automobile system according to claim 8, wherein the difference between the magnitude of the battery voltage, which is the voltage across the battery, and the magnitude of the link voltage is calculated, and the fusion failure of the main contactor is diagnosed by comparing the difference with a predetermined error value.

10. A method for discharging a link capacitor connected in parallel with the battery in an automotive system comprising a main discharge circuit including a main discharge resistor and a main discharge switch connected in series between the positive and negative electrodes of a battery, and an auxiliary discharge circuit including an auxiliary discharge resistor and an auxiliary discharge switch connected in series between the positive and negative electrodes of the battery, When an emergency event occurs, the BMS controls the turn-off of the main contactor connected between the positive electrode of the battery and one end of the link capacitor, as instructed by the higher-level controller. The steps include: the higher-level controller turning on the main discharge switch; The higher-level controller, after the main discharge switch has been controlled, determines whether the magnitude of the link voltage, which is the voltage across the link capacitor, is less than a reference value. If, as a result of the above determination, the magnitude of the link voltage is greater than or equal to the reference value, the BMS controls the auxiliary discharge switch to be turned on; The BMS, after the auxiliary discharge switch has been controlled, determines whether the magnitude of the link voltage is less than the reference value, A method for discharging a link capacitor, comprising the step of the BMS diagnosing a fusion fault in the main contactor if, as a result of the above determination, the magnitude of the link voltage is less than the reference value.

11. After the auxiliary discharge switch is controlled, a step is taken to determine whether the magnitude of the link voltage is less than the reference value, The method for discharging a link capacitor according to claim 10, further comprising the step that, as a result of the above determination, if the magnitude of the link voltage is greater than or equal to the reference value, the BMS generates a first fault alarm message including fault state information of the main discharge circuit and a second fault alarm message including fault state information of the auxiliary discharge circuit.

12. Before the step of diagnosing the fusion failure of the main contactor, A method for discharging a link capacitor according to claim 10, further comprising the step of the BMS generating a first fault alarm message including fault status information of the main discharge circuit if, after the auxiliary discharge switch has been controlled, the magnitude of the link voltage is less than the reference value.

13. The step of diagnosing a fusion failure in the main contactor is as follows: The method for discharging a link capacitor according to claim 10, further comprising the step of the BMS calculating the difference between the magnitude of the battery voltage, which is the voltage across the battery, and the magnitude of the link voltage, and comparing the difference with a predetermined error value to diagnose a fusion failure of the main contactor.

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