Arc discharge protection method and vehicle

Abstract

The application provides an arc discharge protection method and a vehicle. The arc discharge protection method comprises the following steps: obtaining an arc characteristic signal generated by a load during load operation; in the case that the arc characteristic signal indicates that an arc is generated in a power distribution system, calculating arc energy based on the arc characteristic signal; determining a risk level of the load according to the arc energy, and matching a corresponding protection strategy of the power distribution system according to the risk level of the load; and protecting the power distribution system from arc discharge based on the protection strategy. The application can make the absorption of arc energy more targeted and improve the reliability of arc absorption.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-voltage power distribution systems, and particularly relates to an arc discharge protection method and a vehicle. BACKGROUND

[0002] The current low-voltage power supply system of an automobile generally adopts 12V power supply. When a circuit is plugged or disconnected, a small arc may occur, but it will usually self-extinguish quickly and will not cause damage to the controller or the connector. With the increase in the number of electrical devices of the automobile and the increase in the power demand, the low-voltage power supply system is evolving from the traditional 12V to 48V. The 48V system can provide higher power density, but its higher voltage level also makes it more likely to produce an arc phenomenon during the plugging or disconnection of the circuit. The related arc discharge protection scheme relies on a fuse protection, which has a slow response speed and cannot make targeted protection for the arc. SUMMARY

[0003] The present application provides an arc discharge protection method and a vehicle, so that the absorption of arc energy is more targeted and the reliability of arc absorption is improved.

[0004] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0005] In a first aspect, the present application provides an arc discharge protection method, comprising: acquiring an arc characteristic signal generated by a load during operation of the load; in the case that the arc characteristic signal indicates that an arc is generated in a power distribution system, calculating an arc energy based on the arc characteristic signal; determining a risk level of the load according to the arc energy, and matching a corresponding protection strategy of the power distribution system according to the risk level of the load; and performing arc discharge protection on the power distribution system based on the protection strategy.

[0006] It can be understood that the scheme provided by the present application: by acquiring the arc characteristic signal during operation of the load in real time, it is determined whether an arc occurs, and further the risk level of the load is evaluated in combination with the arc energy, and the corresponding protection strategy is matched accordingly, so that the protection strategy of the power distribution system corresponding to different risk levels of the load is matched, the absorption of the arc energy is more targeted, and the reliability of the arc absorption is improved.

[0007] In some embodiments, acquiring the arc characteristic signal generated by the load comprises: acquiring a load current signal and a contact voltage signal in the power distribution system; performing feature extraction on the contact voltage signal to obtain a voltage peak value and a voltage change rate of the arc; performing feature extraction on the load current signal to obtain a current peak value and a current change rate of the arc; and determining the arc characteristic signal according to at least one of the voltage peak value, the voltage change rate, the current peak value and the current change rate of the arc.

[0008] It can be understood that the scheme provided in the embodiments of the present application can obtain an arc characteristic signal by collecting the load current signal and the contact voltage signal in the power distribution system and performing feature extraction, can improve the accuracy of the arc characteristic signal, is conducive to improving the accuracy of subsequent calculation of arc energy, and further makes the matching of the corresponding protection strategy of the power distribution system more accurate.

[0009] In some embodiments, the arc discharge protection method further comprises: determining that the arc characteristic signal indicates that the power distribution system generates an arc in a case where the current rate of change is greater than a preset current rate of change threshold; or determining that the arc characteristic signal indicates that the power distribution system generates an arc in a case where the voltage rate of change is greater than a preset voltage rate of change threshold, and the amplitude of the load current signal is greater than a preset current threshold.

[0010] It can be understood that the scheme provided in the embodiments of the present application can quickly identify the arc phenomenon in the early stage of arc occurrence by extracting the rate of change of the load current as the arc characteristic signal, improve the detection sensitivity and response speed, and provide a reliable basis for the start of the subsequent protection strategy. Alternatively, by jointly using the voltage rate of change and the load current as the arc characteristic signal, the characteristics of arc occurrence can be more comprehensively represented, and the accuracy and robustness of arc identification can be improved, and good detection performance can still be maintained under complex working conditions.

[0011] In some embodiments, the matching of the protection strategy corresponding to the power distribution system according to the risk level of the load comprises: in a case where the risk level of the load is a high-risk level, determining that the protection strategy comprises a protection strategy of a centralized arc absorption circuit and a protection strategy of a distributed arc absorption circuit; in a case where the risk level of the load is a medium-risk level, determining that the protection strategy comprises a protection strategy of a centralized arc absorption circuit; and in a case where the risk level of the load is a low-risk level, determining that the protection strategy comprises a protection strategy of a filter absorption circuit.

[0012] It can be understood that the scheme provided in the embodiments of the present application realizes a hierarchical protection mechanism by selecting different protection strategies according to the risk level of the load, which can ensure the safety of high-risk loads and will not cause excessive protection to low-risk loads, and further improves the reliability of arc absorption.

[0013] In some embodiments, the centralized arc absorption circuit includes a primary protection unit, a secondary protection unit, and a clamping unit, and the protection level of the secondary protection unit is higher than that of the primary protection unit; the primary protection unit is connected in parallel across the input power supply or connector; the input side of the secondary protection unit is connected to the output side of the primary protection unit, and the output side of the secondary protection unit is connected to the input side of the clamping unit; the output side of the clamping unit is connected in parallel to the load; wherein: in the case that the risk level of the load is a high risk level or a medium risk level, the protection strategy of the centralized arc absorption circuit includes: the primary protection unit is used to clamp the surge voltage of the input power supply or connector; the secondary protection unit is used to absorb the voltage spikes missed by the primary protection unit and suppress high-frequency arc energy; and the clamping unit is used to turn on the first transistor in the case of arc generation, so as to make the contact voltage of the circuit breaker in the power distribution system drop to a safety threshold.

[0014] It can be understood that the scheme provided by the embodiments of the present application: through the hierarchical design of the centralized arc absorption circuit, multi-level protection is realized, arc energy is effectively absorbed and contact voltage is limited, device damage or safety accidents caused by arc are prevented, and the safety of the power distribution system can be improved.

[0015] In some embodiments, the distributed arc absorption circuit includes a pre-charge circuit, the pre-charge circuit includes a first switch tube unit, a first driving circuit, a switch array and a second driving circuit; a first end of the load is connected with a first power supply V1, a second end of the load is connected with a first end of the first switch tube unit, a second end of the first switch tube unit is grounded, a control end of the first switch tube unit is connected with an output end of the first driving circuit, and an input end of the first driving circuit is used for receiving a first control signal; a control end of the switch array is connected with an output end of the second driving circuit; the first end of the load is connected with the first power supply, and the second end of the load is connected with the second end of the first switch tube unit; when the risk level of the load is high risk, the strategy of the distributed arc absorption circuit includes: when the power distribution system is powered on, the first switch tube unit and the switch array are controlled to be in an off state; a pre-charge current threshold is determined according to the working state and the demand of the load; when the collected pre-charge current is greater than or equal to the pre-charge current threshold, the duty cycle of the first control signal is reduced, and the first driving circuit outputs the first control signal with the reduced duty cycle to control the time length of the first switch tube unit being turned on or turned off, so that the pre-charge current is less than the pre-charge current threshold; when the pre-charge current is less than the pre-charge current threshold, and the difference between the voltage of the first power supply and the collected pre-charge voltage satisfies a first preset condition, the duty cycle of the first control signal is increased to improve the charging speed of the pre-charge circuit; when the pre-charge current is less than the pre-charge current threshold, and the difference between the voltage of the first power supply and the pre-charge voltage satisfies a second preset condition, the first switch tube unit is controlled to be turned off by the first driving circuit, so that the pre-charge of the pre-charge circuit is completed; and the switch array is controlled to be turned on by the second driving circuit, so that the load enters a normal working state.

[0016] It can be understood that the scheme provided by the embodiments of the present application: by adopting the pre-charge circuit with closed-loop feedback control, the dynamic pre-charge management of the high-risk load is realized, the inrush current at the power-on moment is effectively limited, the possibility of arc generation is reduced, the charging efficiency is improved, and the stable operation of the system is ensured.

[0017] In some embodiments, the filter absorption circuit includes a resistance-capacitance filter circuit; or, the filter absorption circuit includes a resistance-capacitance filter circuit and a transient voltage suppressor.

[0018] It can be understood that the scheme provided by the embodiments of the present application: by adopting the resistance-capacitance filter circuit or the combination structure of the resistance-capacitance filter circuit and the transient voltage suppressor, the high-frequency noise and the transient voltage caused by the arc can be effectively absorbed, which is suitable for the simple protection demand of the low-risk level load, the structure is compact, the cost is low, and it is suitable for large-scale application.

[0019] In some embodiments, the arc energy is calculated based on the arc characteristic signal, including: obtaining a voltage peak value of the arc in the arc characteristic signal and a current peak value of the arc; obtaining a duration of the arc; and performing an integration operation on the voltage peak value of the arc and the current peak value of the arc within the duration to obtain the arc energy.

[0020] It can be understood that the scheme provided by the embodiments of the present application can accurately obtain the arc energy by performing the integration operation on the voltage peak value of the arc and the current peak value of the arc within the duration, thereby improving the accuracy of the arc energy calculation and further improving the accuracy of the subsequent division of the risk level of the load.

[0021] In some embodiments, the risk level of the load is determined according to the arc energy, including: when the arc energy is in a first set range, determining that the risk level of the load is a low risk level; when the arc energy is in a second set range, determining that the risk level of the load is a medium risk level; and when the arc energy is in a third set range, determining that the risk level of the load is a high risk level; wherein the upper limit of the first set range is less than the lower limit of the second set range, and the upper limit of the second set range is less than the lower limit of the third set range.

[0022] It can be understood that the scheme provided by the embodiments of the present application can realize quantitative evaluation of the arc hazard degree by dividing the arc energy into multiple intervals and corresponding to different risk levels, and the quantitative evaluation of the arc hazard degree reflects the risk level of the load. The higher the risk level of the load, the more difficult it is to absorb the arc energy. Such division facilitates accurate matching of subsequent protection strategies, thereby improving the intelligence and adaptability of the power distribution system.

[0023] In some embodiments, the method further includes: obtaining a configuration parameter of the load; and determining a load type of the load based on the configuration parameter of the load; wherein the load type includes a capacitive load and an inductive load.

[0024] It can be understood that the scheme provided by the embodiments of the present application can identify the load type in multiple ways, and distinguishing the load type helps to design a targeted protection strategy to reduce the risk of arc discharge.

[0025] In some embodiments, the configuration parameter of the load includes: an identifier of the load; or an impedance characteristic of a loop in which the load is located; or a relationship between a current phase and a voltage phase of the load.

[0026] It can be understood that the scheme provided by the embodiments of the present application can identify the load type of the load through different configuration parameters of the load, thereby improving the flexibility of determining the load type of the load.

[0027] In a second aspect, the embodiments of the present application provide a vehicle, comprising a power distribution system and a control circuit, the power distribution system being connected to the control circuit; wherein the power distribution system comprises at least a circuit breaker and a protection circuit, the protection circuit comprising at least one of: a centralized arc absorption circuit, a distributed arc absorption circuit and a filter absorption circuit; the control circuit is configured to implement the method of the first aspect. BRIEF DESCRIPTION OF DRAWINGS

[0028] The drawings in the accompanying drawings are incorporated into the specification and constitute a part of the specification, which illustrate the embodiments consistent with the present application, and together with the specification serve to explain the technical solutions of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0029] The flowchart shown in the drawings is only an exemplary illustration, and is not necessarily to include all the contents and operations / steps, nor is it necessarily executed in the order described. For example, some operations / steps can be further decomposed, and some operations / steps can be combined or partially combined, so that the actual execution order can be changed according to the actual situation.

[0030] Figure 1 Flowchart of an arc discharge protection method provided by the embodiments of the present application Figure 1 ;

[0031] Figure 2 Structure diagram of a centralized arc absorption circuit provided by the embodiments of the present application

[0032] Figure 3 Structure diagram of a distributed arc absorption circuit provided by the embodiments of the present application

[0033] Figure 4 Flowchart of an arc discharge protection method provided by the embodiments of the present application Figure 2 ;

[0034] Figure 5 Flowchart of a method for determining the load type of a load provided by the embodiments of the present application

[0035] Figure 6 Structure diagram of an arc discharge protection system provided by the embodiments of the present application

[0036] Figure 7 Diagram of the relationship between the equivalent resistance of a MOS tube and the PWM duty cycle provided by the embodiments of the present application

[0037] Figure 8A schematic diagram of a relationship between a pre-charge voltage and a pre-charge current varying with time is provided for an embodiment of the present application.

[0038] Figure 9 A flowchart of a strategy of a distributed arc absorption loop is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0039] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following will further describe the specific technical solutions of the present application with reference to the drawings in the embodiments of the present application. The following embodiments are used to illustrate the present application, but are not used to limit the scope of the present application.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application, and are not intended to limit the present application.

[0041] In the following description, “some embodiments”, “the embodiment”, “the embodiments of the present application” and the like describe a subset of all possible embodiments, but it can be understood that “some embodiments” can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0042] The “first”, “second”, “third” and the like descriptions appearing in the embodiments of the present application do not have a specific meaning (such as no order, nor represent a special limitation on the number of devices in the embodiments of the present application), and are only for the convenience of clearly describing the embodiments of the present application, and cannot constitute any limitation on the embodiments of the present application.

[0043] To facilitate understanding of the technical solutions of the embodiments of the present application, the related technologies or terms of the embodiments of the present application are described below. The following related technologies or related terms can be arbitrarily combined with the technical solutions of the embodiments of the present application as optional solutions, which all belong to the protection scope of the embodiments of the present application.

[0044] The current automobile low-voltage power distribution generally uses 12V power supply. When the circuit is closed / opened, a small arc may appear, but it will usually extinguish itself quickly and will not cause damage to the controller or the connector. The traditional 12V low-voltage system relies on a fuse for protection, which has a slow response speed and cannot provide targeted protection for the arc.

[0045] With the increasing electrification of automobiles, the power of vehicle loads, and the proliferation of electrical devices, 48V low-voltage power supply systems are becoming the trend. While 48V systems offer higher power density than 12V systems, the lower DC arc sustaining voltage and the generally larger inductance / capacitance of loads make them more prone to sparking and arcing during insertion / removal or disconnection. Capacitive loads (such as large capacitors in controllers or DC-to-DC input current) generate huge inrush currents upon power-up; inductive loads (such as motors, pumps, and distributed inductance in wiring harnesses) generate backflow voltage when disconnected. Current solutions often rely on single resistor-capacitor filter circuits or passive absorption using transient voltage suppressors (TVS). However, both resistor-capacitor filter circuits and TVS solutions only provide local suppression, lacking global optimization and failing to simultaneously achieve the system objectives of spark-free insertion / removal, inductive voltage absorption, overvoltage clamping, and continuous controllability.

[0046] Furthermore, in related technologies, the pre-charging methods for large surge currents on loads are mostly fixed resistor pre-charging, relay-level pre-charging, or electronic switch pre-charging. However, while fixed resistor pre-charging is simple, it has a long pre-charging time and high energy consumption. Relay-level pre-charging improves efficiency to some extent, but it suffers from contact wear and insufficient lifespan. Electronic switch pre-charging, if using open-loop control, cannot balance speed and safety. Therefore, none of the above pre-charging solutions can meet the needs of future high-power electrical systems and the ability to adaptively adjust the pre-charging time according to load differences, and they are not effective at absorbing electric arcs.

[0047] In related technologies, control circuits identify circuit voltage / current to determine whether a parallel arc or a series arc is generated, and promptly disconnect the line load to avoid consequences such as fire caused by arc discharge.

[0048] Based on this, the inventors of this application discovered through research and analysis that the relevant arc discharge protection schemes rely on fuse protection, which has a slow response speed and cannot provide targeted protection against arcs.

[0049] Based on this, embodiments of this application provide the following arc discharge protection methods and vehicles, etc.

[0050] Figure 1 A flowchart illustrating an arc discharge protection method provided in this application embodiment. Figure 1 ,like Figure 1 As shown, the arc discharge protection method includes the following steps:

[0051] S101. During load operation, acquire the arc characteristic signal generated by the load.

[0052] S102, in the case that the arc characteristic signal indicates that the power distribution system generates an arc, determining the arc energy based on the arc characteristic signal.

[0053] S103, determining the risk level of the load according to the arc energy, and matching the corresponding protection strategy of the power distribution system according to the risk level of the load.

[0054] S104, protecting the power distribution system from arc discharge based on the protection strategy.

[0055] It can be understood that, by collecting the arc characteristic signal during the operation of the load in real time, it is determined whether an arc occurs, and further, the risk level of the load is evaluated in combination with the arc energy, and accordingly, the corresponding protection strategy is matched, so that the protection strategy of the power distribution system corresponding to different risk levels of the load is matched, the absorption of the arc energy is more targeted, and the reliability of the arc absorption is improved.

[0056] The further optional embodiments of each of the above steps and related terms are described below.

[0057] S101, during the operation of the load, acquiring an arc characteristic signal generated by the load.

[0058] In an example, acquiring the arc characteristic signal generated by the load can be: collecting a load current signal Is and a contact voltage signal Vs in the power distribution system; performing feature extraction on the contact voltage signal Vs to obtain a voltage peak value U arc of the arc and a voltage change rate; performing feature extraction on the load current signal Is to obtain a current peak value I arc of the arc and a current change rate; and determining the arc characteristic signal according to at least one of the voltage peak value U arc , the voltage change rate, the current peak value I arc of the arc and the current change rate.

[0059] In another example, acquiring the arc characteristic signal generated by the load can be: a spike of the contact voltage signal Vs, a current mutation rate and a high-frequency oscillation of the load current signal Is, and the like.

[0060] The method of "acquiring the arc characteristic signal generated by the load" is not particularly limited in the present application.

[0061] It can be understood that, the scheme provided by the embodiments of the present application: by collecting the load current signal and the contact voltage signal in the power distribution system and performing feature extraction, the arc characteristic signal can be obtained, the accuracy of the arc characteristic signal can be improved, which is beneficial to improve the accuracy of the subsequent calculation of the arc energy, and further makes the matching of the corresponding protection strategy of the power distribution system more accurate.

[0062] S102, in a case where the arc characteristic signal indicates that the power distribution system generates an arc, calculating an arc energy based on the arc characteristic signal.

[0063] In an example, in a case where the current rate of change is greater than a preset current rate of change threshold, it is determined that the arc characteristic signal indicates that the power distribution system generates an arc.

[0064] In yet another example, in a case where the voltage rate of change is greater than a preset voltage rate of change threshold, and the value of the load current signal is greater than a preset current threshold, it is determined that the arc characteristic signal indicates that the power distribution system generates an arc.

[0065] Exemplarily, the preset voltage rate of change threshold can be 50V / μs; and the preset current threshold can be 10A. It can be understood that "50V / μs" is an exemplary data of the preset voltage rate of change threshold, and is not specific, in actual application, the preset voltage rate of change threshold can be changed according to actual needs, and the present application does not particularly limit this; "10A" is an exemplary data of the preset current threshold, and is not specific, in actual application, the preset current threshold can be changed according to actual needs, and the present application does not particularly limit this.

[0066] It can be understood that by extracting the rate of change of the load current as the arc characteristic signal, the arc phenomenon can be quickly identified at the initial stage of the arc, the detection sensitivity and response speed are improved, and a reliable basis is provided for the start of the subsequent protection strategy. Alternatively, by jointly using the voltage rate of change and the load current as the arc characteristic signal, the characteristics of the arc occurrence can be more comprehensively represented, and the accuracy and robustness of the arc identification are improved, and good detection performance can still be maintained under complex working conditions.

[0067] In some embodiments, the voltage peak value U arc of the arc and the current peak value I arc of the arc in the arc characteristic signal are obtained. arc arc The duration tarc of the arc is obtained; and the voltage peak value U arc of the arc and the current peak value I arc of the arc are integrated within the duration tarc to obtain the arc energy E arc .

[0068] Exemplarily, the arc energy E arc may be determined by the following formula (1):

[0069] (1)

[0070] Wherein, U arc represents the voltage peak value of the arc, i.e. the peak voltage of the contact voltage Vs, which can be obtained by a voltage sensor; I arcThe peak current of the arc, i.e. the peak current of the load current signal Is, can be collected by the current sensor; t1 represents the starting time of the arc; t2 represents the ending time of the arc; the difference between the ending time t2 of the arc and the starting time t1 of the arc is the duration tarc of the arc, i.e. the total duration from the starting time of the arc to the ending time of the arc, which can be obtained by a timer.

[0071] It can be understood that by integrating the voltage peak value of the arc and the current peak value of the arc within the duration, the arc energy can be accurately obtained, the accuracy of the arc energy calculation is improved, and the accuracy of the subsequent division of the risk level of the load is further improved.

[0072] S103, determining the risk level of the load according to the arc energy, and matching the corresponding protection strategy of the power distribution system according to the risk level of the load.

[0073] In an optional embodiment, determining the risk level of the load according to the arc energy comprises: when the arc energy E arc is located in the first set range, determining the risk level of the load as a low risk level; when the arc energy E arc is located in the second set range, determining the risk level of the load as a medium risk level; and when the arc energy E arc is located in the third set range, determining the risk level of the load as a high risk level.

[0074] It can be understood that the size of the arc energy is positively correlated with the harm intensity of the load. That is, the greater the arc energy, the greater the harm degree to the subsequent load, and the higher the risk level of the load.

[0075] The upper limit of the first set range is less than the lower limit of the second set range; the upper limit of the second set range is less than the lower limit of the third set range.

[0076] Exemplarily, the first set range can be: less than 5 megajoules (MJ), i.e. [0, 5 MJ); the second set range can be: greater than or equal to 5 MJ and less than or equal to 20 MJ, i.e. [5 MJ, 20 MJ]; and the third set range can be: greater than 20 MJ, i.e. (20 MJ, +∞). That is, when the arc energy E arc < 5 MJ, it is determined as a low risk; when 5 MJ ≤ the arc energy E arc ≤ 20 MJ, it is determined as a low risk; and when the arc energy E arc > 20 MJ, it is determined as a high risk.

[0077] The numerical value of the risk level division can be dynamically adjusted according to the load type, and the characteristics of the 48V low-voltage power supply system, the load type, the contact material tolerance limit and the safety standard need to be considered comprehensively.

[0078] It should be noted that the higher the risk level of the load, the more difficult it is to absorb arc energy, and the more likely it is to cause danger.

[0079] Exemplarily, in the 48V low-voltage power distribution system of the vehicle, the high-risk level load can include but is not limited to electric drive and battery, etc.; the medium-risk level load can include but is not limited to the compressor of the air conditioner, etc.; and the low-risk level load can include but is not limited to the vehicle lamp, etc.

[0080] It can be understood that by dividing the arc energy into multiple intervals and corresponding to different risk levels, the quantitative evaluation of the arc hazard degree is realized, and the quantitative evaluation of the arc hazard degree reflects the risk level of the load. The higher the risk level of the load, the more difficult it is to absorb arc energy. This division facilitates accurate matching of subsequent protection strategies and improves the intelligence and adaptability of the power distribution system.

[0081] In an optional embodiment, in order to realize the targeted arc discharge protection strategy and improve the reliability of arc absorption, the corresponding protection strategy of the power distribution system is matched according to the risk level of the load, which includes:

[0082] In the case where the risk level of the load is a high-risk level, the protection strategy includes the protection strategy of the centralized arc absorption circuit and the protection strategy of the distributed arc absorption circuit.

[0083] In the case where the risk level of the load is a medium-risk level, the protection strategy includes the protection strategy of the centralized arc absorption circuit.

[0084] In the case where the risk level of the load is a low-risk level, the protection strategy includes the protection strategy of the filter absorption circuit.

[0085] It can be understood that by selecting different protection strategies according to the risk level of the load, a hierarchical protection mechanism is realized, which can ensure the safety of high-risk loads and will not cause excessive protection to low-risk loads, and further improves the reliability of arc absorption.

[0086] The following will be described in detail Figure 2 and Figure 3 respectively.

[0087] Figure 2 A structure diagram of a centralized arc absorption circuit provided by an embodiment of the present application is shown in FIG. 1. Figure 2As shown, the centralized arc absorption circuit 20 includes a first protection unit 201, a second protection unit 202, and a clamping unit 203.

[0088] The protection level of the second protection unit 203 is higher than that of the first protection unit 201.

[0089] Specifically, the first protection unit 201 is connected in parallel across the input power source VIN or the plug. The present application does not make special limitations thereon, and the subsequent example takes the first protection unit 201 connected in parallel across the input power source VIN as an example for illustrative description. The input side of the second protection unit 202 is connected to the output side of the first protection unit 201, and the output side of the second protection unit 202 is connected to the input side of the clamping unit 203; the output side of the clamping unit 203 is connected in parallel to the load 701.

[0090] Specifically, the first protection unit 201 can include a pressure sensitive resistor MOV; the second protection unit 202 can include a resistor-capacitor filter circuit and a first transient voltage suppressor TVS1; and the clamping unit 203 can include a first transistor Q1, a bias resistor R3, a first zener diode D1, a second zener diode D2, and a low-pass filter circuit.

[0091] The resistor-capacitor filter circuit includes a first resistor R1, a first capacitor C1, a second capacitor C2, and a second resistor R2; and the low-pass filter circuit includes a third capacitor C3 and a fourth resistor R4.

[0092] The first transient voltage suppressor TVS1 is selected from a transient voltage suppression diode to protect the circuit from voltage spikes.

[0093] Specifically, the first end of the pressure sensitive resistor MOV is connected to the first end of the input power VIN and the first resistor R1 respectively, and the second end of the pressure sensitive resistor MOV is grounded; the second end of the first resistor R1 is connected to the first end of the first transient voltage suppressor TVS1, the anode plate of the first capacitor C1, the first end of the second resistor R2 and the first end of the first transistor Q1 respectively; the second end of the first transient voltage suppressor TVS1 is grounded, the cathode plate of the first capacitor C1 is connected to the anode plate of the second capacitor C2, and the cathode plate of the second capacitor C2 is grounded; the second end of the second resistor R2 is grounded; the first end of the first transistor Q1 is also connected to the anode plate of the third capacitor C3 and the negative electrode of the second zener diode D2 respectively, the second end of the first transistor Q1 is grounded, and the control end of the first transistor Q1 is connected to the control circuit; the cathode plate of the third capacitor C3 is connected to the first end of the fourth resistor R4, and the second end of the fourth resistor R4 is grounded; the positive electrode of the second zener diode D2 is grounded; the bias resistor R3 is connected in parallel between the control end and the second end of the first transistor Q1; the first zener diode D1 is connected in parallel between the control end and the second end of the first transistor Q1, and the conduction direction is directed to the control end of the first transistor Q1; the load 701 is connected in parallel across the second zener diode D2.

[0094] In an embodiment, the second end of the pressure sensitive resistor MOV, the second end of the first transient voltage suppressor TVS1, the cathode plate of the second capacitor C2, the second end of the second resistor R2, the second end of the first transistor Q1 and the second end of the fourth resistor R4 can be grounded.

[0095] Wherein, the first transistor Q1 can be a Metal-Oxide Semiconductor Field-Effect Transistor (MOSFET), simply referred to as MOS tube; the first transistor Q1 can also be a Bipolar Junction Transistor (BJT), simply referred to as a triode. This application does not make special limitation, and the subsequent example is taken as an N-channel MOS tube for example. In the case of the first transistor Q1 being an N-channel MOS tube, the source of the first transistor Q1 is the first end of the first transistor Q1, the drain of the first transistor Q1 is the second end of the first transistor Q1, and the gate of the first transistor Q1 is the control end of the first transistor Q1.

[0096] For example, the input power VIN can be 48V.

[0097] It can be understood that the resistance-capacitance filter circuit includes a first resistor R1, a first capacitor C1, a second capacitor C2 and a second resistor R2, the first resistor R1, the first capacitor C1 and the second capacitor C2 can form a low-pass filter, when the voltage signal frequency of the input power VIN is low, the capacitive reactance of the first capacitor C1 and the second capacitor C2 is large, the voltage drop on the first resistor R1 is small, and the output voltage across the first capacitor C1 and the second capacitor C2 after being connected in series is close to the voltage of the input power VIN; when the frequency increases, the capacitive reactance decreases, the output voltage across the first capacitor C1 and the second capacitor C2 after being connected in series decreases, signal attenuation is achieved, and the purpose of filtering is achieved; the first capacitor C1, the second capacitor C2 and the second resistor R2 can form a high-pass filter, the cutoff frequency can be controlled by adjusting the values of the first capacitor C1, the second capacitor C2 and the second resistor R2, high-frequency signal attenuation or amplification is achieved, and the purpose of filtering is achieved.

[0098] In the case where the risk level of the load 701 is a high risk level or a medium risk level, the protection strategy of the centralized arc absorption circuit 20 includes: the first protection unit 201 is used for clamping the surge voltage of the input power VIN or the connector; the second protection unit 202 is used for absorbing the voltage spikes missed by the first protection unit 201 and suppressing high-frequency arc energy; and the control circuit controls the conduction of the clamping unit 203, so that the contact voltage Vs decreases to a safety threshold.

[0099] Wherein, the contact voltage Vs can be the voltage across the contacts of the contactor or the circuit breaker or the relay and the like on the connection line between the power distribution system and the load, which is not particularly limited in the present application, and will be exemplarily described below taking the voltage across the contacts of the circuit breaker as an example.

[0100] Exemplarily, the safety threshold can be less than or equal to 60V.

[0101] It can be understood that, by using the hierarchical design of the centralized arc absorption circuit, multi-level protection is achieved, arc energy is effectively absorbed and the contact voltage is limited, device damage or safety accidents caused by arc are prevented, and the safety of the power distribution system can be improved.

[0102] Figure 3 A structure diagram of a distributed arc absorption circuit provided by the embodiment of the present application is shown in FIG. 6, which includes a pre-charge circuit. Figure 3 The pre-charge circuit includes a first switch tube unit 306, a first drive circuit 305, a switch array 308 and a second drive circuit 307.

[0103] Specifically, the first end of the load 701 is connected with the first power supply V1, the second end of the load 701 is connected with the first end of the first switch tube unit 306, the second end of the first switch tube unit 306 is grounded GND, the control end of the first switch tube unit 306 is connected with the output end of the first drive circuit 305, and the input end of the first drive circuit 305 is used for receiving the first control signal h1; the control end of the switch array 308 is connected with the output end of the second drive circuit 307; the first end of the load 701 is connected with the first power supply V1, and the second end of the load 701 is connected with the second end of the first switch tube unit 306.

[0104] At this time, when the risk level of the load 701 is high risk, the strategy of the distributed arc absorption loop includes: when the power distribution system is powered on, controlling the first switch tube unit 306 and the switch array 308 to be in an off state; determining a pre-charge current threshold according to the working state and demand of the load; in the case that the collected pre-charge current is greater than or equal to the pre-charge current threshold, reducing the duty cycle of the first control signal h1, and controlling the first drive circuit 305 to output the first control signal with the reduced duty cycle, so as to control the length of time for which the first switch tube unit 306 is turned on or turned off, so that the pre-charge current is less than the pre-charge current threshold; in the case that the pre-charge current is less than the pre-charge current threshold, and the difference between the voltage of the first power supply and the collected pre-charge voltage satisfies a first preset condition, increasing the duty cycle of the first control signal h1 to improve the charging speed of the pre-charge circuit; in the case that the pre-charge current is less than the pre-charge current threshold, and the difference between the voltage of the first power supply and the pre-charge voltage satisfies a second preset condition, controlling the first switch tube unit 306 to be turned off through the first drive circuit 305, so that the pre-charge of the pre-charge circuit is completed; and controlling the switch array 308 to be turned on through the second drive circuit 307, so that the load enters a normal working state.

[0105] Wherein, the load 701 can be an inductive load or a capacitive load, which is not particularly limited in the present application, and in the following, the load 701 is taken as an inductive load for example and is described by way of illustration. When the load 701 is an inductive load, it can be a capacitor array (also referred to as a pre-charge capacitor unit), which includes at least one capacitor. When the capacitor array includes two or more capacitors, the capacitors are arranged side by side, and in the following, the capacitor array is taken as an example including three capacitors for description by way of illustration.

[0106] In an embodiment, the supply voltage of the first power supply V1 can be taken from the voltage Vbatt of the battery system, which can be 12V.

[0107] In another alternative embodiment, the pre-charge circuit can further include: a voltage detection circuit 301, a pre-charge capacitor unit, a resistance sampling unit 303, and a current limiting resistance unit 304.

[0108] Specifically, the first ends of the voltage detection circuit 301 are connected to the first ends of the first power supply V1 and the pre-charge capacitor unit (i.e., the load 701) respectively; the second end of the pre-charge capacitor unit is connected to the first end of the resistance sampling unit 303; the second end of the resistance sampling unit 303 is connected to the first end of the current-limiting resistance unit 304 and the first end of the first switch tube unit 306 respectively, and the current detection device 90 is also connected in parallel across the resistance sampling unit 303; the second end of the first switch tube unit 306 and the second end of the current-limiting resistance unit 304 are grounded GND; the control end of the first switch tube unit 306 is connected to the output end of the first drive circuit 305, and the signal input end of the first drive circuit 305 is connected to the first control signal h1; the output end of the second drive circuit 307 is connected to the control end of the switch array 308, and the signal input end of the second drive circuit 307 is connected to the second control signal h2; the first end of the switch array 308 is connected to the first end of the resistance sampling unit 303; the first end of the load 701 is connected to the first end of the pre-charge capacitor unit, and the second end of the load 701 is grounded GND.

[0109] The voltage detection circuit 301 is configured to detect the voltage of the pre-charge circuit and obtain a pre-charge voltage; and the current detection device 90 is configured to collect the current of the pre-charge circuit and obtain a pre-charge current.

[0110] As an optional embodiment, in order to ensure the smooth conduction of the switch array 308, the distributed electric arc absorption loop provided in the embodiment of the application can further include a signal self-checking circuit 302 arranged on the connection line between the output end of the second drive circuit 307 and the control end of the switch array 308. The signal self-checking circuit 302 is configured to detect the signal output by the output end of the second drive circuit 307, and output the signal output by the output end of the second drive circuit 307 to the control end of the switch array 308 when the signal output by the output end of the second drive circuit 307 meets the set condition.

[0111] Exemplarily, the voltage detection circuit 301 includes a fifth diode D5, a sixth diode D6, a ninth capacitor C9, an eighteenth resistance R18 and a nineteenth resistance R19. Specifically, the cathode of the fifth diode D5 is connected to the fourth power supply V4, the anode of the fifth diode D5 is connected to the negative electrode of the sixth diode D6 and the anode plate of the ninth capacitor C9 respectively; the anode plate of the ninth capacitor C9 can be used as a sampling port h4 of the voltage detection circuit 301; the first end of the eighteenth resistance R18 is connected to the first power supply V1 as the first end of the voltage sampling resistance 301, and the second end of the eighteenth resistance R18 is connected to the first end of the nineteenth resistance R19; the anode of the sixth diode D6, the cathode plate of the ninth capacitor C9 and the second end of the nineteenth resistance R19 are grounded GND.

[0112] Exemplarily, the pre-charge capacitor unit includes a plurality of parallel capacitors, for example, three capacitors, i.e., a sixth capacitor C6, a seventh capacitor C7 and an eighth capacitor C8. The anode plate of the seventh capacitor C7 can be selected as the first end of the pre-charge capacitor unit (i.e., the first end of the load 701) and the first end of the eighteenth resistor R18, and the cathode plate of the seventh capacitor C7 can be selected as the second end of the pre-charge capacitor unit (i.e., the second end of the load 701) and the first end of the resistance sampling unit 303. The sixth capacitor C6 is connected in parallel across the seventh capacitor C7, and the eighth capacitor C8 is connected in parallel across the seventh capacitor C7.

[0113] Exemplarily, the resistance sampling unit 303 includes at least one sampling resistor. When two or more sampling resistors are included, the plurality of sampling resistors are connected in series. The present application does not make special limitation on this, and the following is exemplarily described by taking the resistance sampling unit 303 including one sampling resistor Rs as an example. The first end of the sampling resistor Rs is connected as the first end of the resistance sampling unit 303 and the second end of the pre-charge capacitor unit, and the second end of the sampling resistor Rs is connected as the second end of the resistance sampling unit 303 and the first end of the current-limiting resistor unit 304 and the first end of the first switch tube unit 306.

[0114] Exemplarily, the current-limiting resistor unit 304 includes at least one current-limiting resistor. When two or more current-limiting resistors are included, the plurality of current-limiting resistors are connected in parallel. The present application does not make special limitation on this, and the following is exemplarily described by taking the current-limiting resistor unit 304 including one current-limiting resistor R22 as an example. The first end of the current-limiting resistor R22 is connected as the first end of the current-limiting resistor unit 304 and the second end of the sampling resistor Rs, and the second end of the current-limiting resistor R22 is connected as the second end of the current-limiting resistor unit 304 and the ground GND.

[0115] Exemplarily, the first driving circuit 305 comprises a second transistor Q2, a third transistor Q3, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16 and a seventeenth resistor R17. Specifically, the control end of the second transistor Q2 is connected with the first control signal h1 as the signal input end of the first driving circuit 305, the first end of the second transistor Q2 is connected with the second power supply V2 and the control end of the third transistor Q3 respectively, the second end of the second transistor Q2 and the second end of the third transistor Q3 are grounded GND; the first end of the third transistor Q3 is connected with the second power supply V2 and the control end of the first switch tube unit 306 as the output end of the first driving circuit 305; the sixteenth resistor R16 is arranged in series on the connecting line between the control end of the second transistor Q2 and the first control signal h1; the fourteenth resistor R14 is arranged in series on the connecting line between the first end of the second transistor Q2 and the second power supply V2; the first end of the seventeenth resistor R17 is connected with the control end of the second transistor Q2, and the second end of the seventeenth resistor R17 is connected with the second end of the second transistor Q2; the fifteenth resistor R15 is arranged in series on the connecting line between the first end of the third transistor Q3 and the second power supply V2.

[0116] Wherein, the sixteenth resistor R16 plays a current limiting role; the seventeenth resistor R17 plays a biasing role; the fourteenth resistor R14 and the fifteenth resistor R15 play a role of pull-up resistor.

[0117] Wherein, the second transistor Q2 and the third transistor Q3 can be MOS tubes or BJT tubes, and the present application does not make special limitation thereto, and the subsequent example will be exemplarily described by taking the second transistor Q2 and the third transistor Q3 as NPN type triodes. It can be understood that when the second transistor Q2 is an NPN type transistor, the base of the second transistor Q2 is the control end of the second transistor Q2, that is, the signal input end of the first driving circuit 305, the collector of the second transistor Q2 is the first end of the second transistor Q2, and the emitter of the second transistor Q2 is the second end of the second transistor Q2. When the third transistor Q3 is an NPN type transistor, the base of the third transistor Q3 is the control end of the third transistor Q3, the collector of the third transistor Q3 is the first end of the third transistor Q3, that is, the output end of the first driving circuit 305, and the emitter of the third transistor Q3 is the second end of the third transistor Q3.

[0118] Exemplarily, the first switch tube unit 306 comprises a first switch tube MOS1, a twentieth resistor R20, a twenty-first resistor R21 and a tenth capacitor C10. Specifically, a control end of the first switch tube MOS1 is connected to a collector of the third transistor Q3 as a control end of the first switch tube unit 306; a first end of the first switch tube MOS1 is connected to a second end of the sampling resistor Rs as a first end of the first switch tube unit 306; a second end of the first switch tube MOS1 is grounded GND as a second end of the first switch tube unit 306; the twentieth resistor R20 is arranged in series on a connecting line between the control end of the first switch tube MOS1 and the collector of the third transistor Q3; an anode plate of the tenth capacitor C10 is connected to the control end of the first switch tube MOS1, and a cathode plate of the tenth capacitor C10 is connected to the second end of the first switch tube MOS1; a first end of the twenty-first resistor R21 is connected to the control end of the first switch tube MOS1, and a second end of the twenty-first resistor R21 is connected to the second end of the first switch tube MOS1.

[0119] The first switch tube MOS1 can be a MOS tube or a BJT tube, which is not particularly limited in the present application. Hereinafter, the first switch tube MOS1 is taken as an N-type MOS tube for example, and an exemplary description is made. It can be understood that when the first switch tube MOS1 is an N-type MOS tube, a gate of the first switch tube MOS1 is a control end of the first switch tube MOS1, i.e. a control end of the first switch tube unit 306, a drain of the first switch tube MOS1 is a first end of the first switch tube MOS1, i.e. a first end of the first switch tube unit 306, and a source of the first switch tube MOS1 is a second end of the first switch tube MOS1, i.e. a second end of the first switch tube unit 306.

[0120] It should be noted that the first switch tube MOS1 is an N-type MOS tube with a body diode (which can also be called a parasitic diode or a freewheeling diode).

[0121] The twentieth resistor R20 functions as a current limiter; the twenty-first resistor R21 functions as a bias; and the tenth capacitor C10 functions as a gate voltage surge suppressor of the first switch tube MOS1.

[0122] Exemplarily, the second driving circuit 307 comprises a fourth transistor Q4, a fifth transistor Q5, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12 and a thirteenth resistor R13. Specifically, the control end of the fourth transistor Q4 is connected with the second control signal h2 as the signal input end of the second driving circuit 307, the first end of the fourth transistor Q4 is connected with the third power supply V3 and the control end of the fifth transistor Q5, respectively, the second end of the fourth transistor Q4 and the second end of the fifth transistor Q5 are grounded GND; the first end of the fifth transistor Q5 is connected with the third power supply V3 and the control end of the switch array 308 as the output end of the second driving circuit 307; the twelfth resistor R12 is arranged in series on the connection line between the control end of the fourth transistor Q4 and the second control signal h2; the tenth resistor R10 is arranged in series on the connection line between the first end of the fourth transistor Q4 and the third power supply V3; the first end of the thirteenth resistor R13 is connected with the control end of the fourth transistor Q4, and the second end of the thirteenth resistor R13 is connected with the second end of the fourth transistor Q4; the eleventh resistor R11 is arranged in series on the connection line between the first end of the fifth transistor Q5 and the third power supply V3.

[0123] Wherein, the twelfth resistor R12 plays a current limiting role; the thirteenth resistor R13 plays a biasing role; the tenth resistor R10 and the eleventh resistor R11 play a role of pull-up resistor.

[0124] Wherein, the fourth transistor Q4 and the fifth transistor Q5 can be MOS tubes or BJT tubes, which are not particularly limited in the present application, and the subsequent example will be described taking the fourth transistor Q4 and the fifth transistor Q5 as NPN type triodes. It can be understood that when the fourth transistor Q4 is an NPN type triode, the base of the fourth transistor Q4 is the control end of the fourth transistor Q4, that is, the signal input end of the second driving circuit 307, the collector of the fourth transistor Q4 is the first end of the fourth transistor Q4, and the emitter of the fourth transistor Q4 is the second end of the fourth transistor Q4. When the fifth transistor Q5 is an NPN type triode, the base of the fifth transistor Q5 is the control end of the fifth transistor Q5, the collector of the fifth transistor Q5 is the first end of the fifth transistor Q5, that is, the output end of the second driving circuit 307, and the emitter of the fifth transistor Q5 is the second end of the fifth transistor Q5.

[0125] Exemplarily, the switch array 308 includes at least one switch tube. The application does not particularly limit this, and the subsequent example takes the switch array including three switch tubes, namely the second switch tube MOS2, the third switch tube MOS3 and the fourth switch tube MOS4, as an example for exemplarily description. Further, the switch array 308 can also include the current-limiting resistor R5, the current-limiting resistor R6 and the current-limiting resistor R7. Specifically, the control end of the second switch tube MOS2, the control end of the third switch tube MOS3 and the control end of the fourth switch tube MOS4 are connected together as the control end of the switch array 308 and the collector of the fifth transistor Q5; the first end of the second switch tube MOS2, the first end of the third switch tube MOS3 and the first end of the fourth switch tube MOS4 are connected together as the first end of the switch array 308 and the first end of the sampling resistor Rs; the second end of the second switch tube MOS2, the second end of the third switch tube MOS3 and the second end of the fourth switch tube MOS4 are connected together as the second end of the switch array 308 and the ground GND; the current-limiting resistor R5 is arranged in series on the connection line between the control end of the second switch tube MOS2 and the collector of the fifth transistor Q5; the current-limiting resistor R6 is arranged in series on the connection line between the control end of the third switch tube MOS3 and the collector of the fifth transistor Q5; and the current-limiting resistor R7 is arranged in series on the connection line between the control end of the fourth switch tube MOS4 and the collector of the fifth transistor Q5.

[0126] Among them, the second switch tube MOS2, the third switch tube MOS3 and the fourth switch tube MOS4 can be MOS tubes or BJT tubes, and the application does not particularly limit this, and the subsequent example takes the second switch tube MOS2, the third switch tube MOS3 and the fourth switch tube MOS4 as N-channel MOS tubes (referred to as "N-type MOS tubes") as an example for exemplarily description. It can be understood that when the second switch tube MOS2 is an N-type MOS tube, the gate of the second switch tube MOS2 is the control end of the second switch tube MOS2, the drain of the second switch tube MOS2 is the first end of the second switch tube MOS2, and the source of the second switch tube MOS2 is the second end of the second switch tube MOS2. When the third switch tube MOS3 is an N-type MOS tube, the gate of the third switch tube MOS3 is the control end of the third switch tube MOS3, the drain of the third switch tube MOS3 is the first end of the third switch tube MOS3, and the source of the third switch tube MOS3 is the second end of the third switch tube MOS3. When the fourth switch tube MOS4 is an N-type MOS tube, the gate of the fourth switch tube MOS4 is the control end of the fourth switch tube MOS4, the drain of the fourth switch tube MOS4 is the first end of the fourth switch tube MOS4, and the source of the fourth switch tube MOS4 is the second end of the fourth switch tube MOS4.

[0127] It should be noted that the second switch tube MOS2, the third switch tube MOS3 and the fourth switch tube MOS4 are N-type MOS tubes with body diodes.

[0128] Exemplarily, the signal self-checking circuit 302 includes a third diode D3, a fourth diode D4, a fifth capacitor C5, a fourth capacitor C4, an eighth resistor R8 and a ninth resistor R9. Specifically, the cathode of the third diode D3 is connected to the third power supply V3, and the anode of the third diode D3 is respectively connected to the negative electrode of the fourth diode D4 and the anode plate of the fifth capacitor C5; the first end of the eighth resistor R8 is connected to the control end of the switch array 308 as the second end of the signal self-checking circuit 302, and the second end of the eighth resistor R8 is connected to the first end of the ninth resistor R9; the first end of the ninth resistor R9 is also connected to the anode plate of the fifth capacitor C5; the anode plate of the fifth capacitor C5 is also connected to the third control signal h3; the anode of the fourth diode D4, the cathode plate of the fifth capacitor C5, the cathode plate of the fourth capacitor C4 and the second end of the ninth resistor R9 are connected together as the third end of the signal self-checking circuit 302 connected to the ground GND; and the anode plate of the fourth capacitor C4 is connected to the collector of the fifth transistor Q5 and the first end of the eighth resistor R8 as the first end of the signal self-checking circuit 302.

[0129] At this time, when the risk level of the load 701 is high risk, the strategy of the distributed arc absorption loop includes:

[0130] S1021, when the power distribution system is powered on, the first drive circuit 301 is controlled to be turned off to realize the turn-off of the first switch tube unit 306; and the second drive circuit 302 is controlled to be turned off to realize the turn-off of the switch array 308.

[0131] It can be understood that since the first switch tube MOS1 in the first switch tube unit 306 connected to the output end of the first drive circuit 301 is an N-type MOS tube, it has the characteristics of "high level on and low level off", so when the first drive circuit 301 is turned off, the output end of the first drive circuit 301 is equivalent to providing a low level to the gate of the first switch tube MOS1, so that the first switch tube MOS1 is in the off state, realizing the turn-off of the first switch tube unit 306.

[0132] It can be understood that since the second switch MOS2, the third switch MOS3 and the fourth switch MOS4 in the switch array 308 connected with the output end of the second driving circuit 307 are all N-type MOS tubes, having the characteristics of "high level on and low level off", when the output end of the second driving circuit 307 is off, the output end is equivalent to providing a low level to the gate of the second switch MOS2, the gate of the third switch MOS3 and the gate of the fourth switch MOS4, so that the second switch MOS2, the third switch MOS3 and the fourth switch MOS4 are in the off state, realizing the off of the switch array 308.

[0133] At this time, the current flow path is: starting from the first power supply V1, flowing through the pre-charge capacitor unit (i.e. the load 701), the resistance sampling unit 303 and the current limiting resistance unit 304 and then grounding.

[0134] Since the resistance value of the current limiting resistance unit 304 is large, the initial inrush current will be limited to a very safe low level. At this time, the current detection device 90 will detect an initial current, which is the pre-charge current, which will gradually decrease with the charging of the pre-charge capacitor unit.

[0135] S1022, according to the working state and demand of the load 701, determine the pre-charge current threshold.

[0136] Exemplarily, the pre-charge current threshold can be adaptively adjusted according to the working state and demand of the load 701. For example, if the working state of the load 701 is power reduction, the demand of the pre-charge current for the load 701 at this time is reduced, at this time, the pre-charge current threshold can be set to the upper limit I th1 of the pre-charge current threshold; if the working state of the load 701 is power increase, the demand of the pre-charge current for the load 701 is increased, at this time, the pre-charge current threshold can be set to the lower limit I th2 of the pre-charge current threshold. The present application does not particularly limit this, and the following will be exemplarily described taking the pre-charge current threshold as the upper limit I th1 of the pre-charge current threshold as an example.

[0137] S1023, collect the pre-charge current between the resistance sampling unit 303 and the pre-charge voltage at the sampling port h4 of the voltage detection circuit 301.

[0138] It can be understood that since the resistance sampling unit 303 is connected with the current detection device 90, the pre-charge current can be obtained through the current detection device 90.

[0139] It can be understood that, since the function of the voltage detection circuit 301 is to detect the voltage, the pre-charge voltage can be obtained by collecting the voltage at the sampling port h4 of the voltage detection circuit 301.

[0140] S1024, it is determined whether the pre-charge current is less than the pre-charge current threshold value. If not, S1025 is executed; if yes, S1026 is executed.

[0141] It can be understood that, since the function of the voltage detection circuit 301 is to detect the voltage, the pre-charge voltage can be obtained by collecting the voltage at the sampling port h4 of the voltage detection circuit 301. th1 For example, the size relationship between the pre-charge current and the upper limit I th1 of the pre-charge current threshold value needs to be determined, that is, it is determined whether the pre-charge current is less than the upper limit value I th1 of the pre-charge current threshold value. If not, S1025 is executed; if yes, S1026 is executed.

[0142] S1025, in the case where the pre-charge current is greater than or equal to the pre-charge current threshold value, the duty cycle of the first control signal h1 is reduced, and the first drive circuit 305 is controlled to output the first control signal h1 with the reduced duty cycle, so as to control the on or off time of the first switch tube unit 306, so that the pre-charge current is less than the pre-charge current threshold value.

[0143] Wherein, the first control signal h1 is issued by the control circuit, and when the pre-charge current gradually decreases with the charging of the pre-charge capacitor unit, the duty cycle of the first control signal h1 can be reduced in the case where the pre-charge current is greater than or equal to the upper limit I th1 of the pre-charge current threshold value, so that the on or off time of the first switch tube unit 306 is controlled, so that the pre-charge current can decrease to be less than the upper limit I th1 of the pre-charge current threshold value.

[0144] Wherein, the first control signal h1 is a pulse width modulation (PWM) signal.

[0145] At this time, the total resistance of the pre-charge circuit is R 总 =R22 / / R eq（MOS1） . Wherein, " / / " means parallel; "R eq（MOS1） " represents the equivalent resistance of the first switch tube MOS1.

[0146] According to the different duty cycles of the PWM signal, the conduction degree of the MOS tube is different, and the equivalent resistance is also different, which can be referred to Figure 7 .

[0147] Figure 7A schematic diagram of the relationship between the equivalent resistance of the MOS tube and the PWM duty cycle provided by the embodiment of the present application can be fitted based on the conduction characteristics of the MOSFET tube and derived by combining the data manual model. Exemplarily, according to the typical on-resistance Rds (on) provided in the MOSFET data manual, combined with the modulation of the PWM signal, the equivalent resistance R eq of the MOS tube at this time is eq =Rds (on) / D.

[0148] Where D represents the on-duty of the MOS tube, and the characteristic curve of the equivalent resistance of the MOS tube varying with the PWM duty cycle can be plotted through the above theoretical relationship, as shown in Figure 7 It should be noted that when the duty cycle of the PWM signal is 100%, it means that the controlled MOS tube is in a fully on state; when the duty cycle of the PWM signal is 0%, it means that the controlled MOS tube is in a fully off state. As can be seen from Figure 7 , when the duty cycle is small, the equivalent resistance is large, and as the duty cycle of the PWM signal gradually approaches 100%, the MOS tube also gradually approaches the fully on state, and then the equivalent resistance of the MOS tube also decreases.

[0149] By detecting the pre-charge current, a closed-loop control system is formed to dynamically adjust the duty cycle of the first control signal h1.

[0150] S1026, judge the relationship between the difference between the voltage of the first power supply and the pre-charge voltage and the first preset condition and the second preset condition, and match the corresponding control strategy.

[0151] It can be understood that as time increases, the pre-charge current will gradually decrease, and the pre-charge voltage will gradually increase, as shown in Figure 8 .

[0152] Specifically, in the case where the pre-charge current is less than the pre-charge current threshold, as described above, the pre-charge current is less than the upper limit I th1 of the pre-charge current threshold, at this time, if the difference between the voltage of the first power supply and the pre-charge voltage satisfies the first preset condition, the duty cycle of the first control signal h1 is increased to increase the charging speed of the pre-charge circuit, and the pre-charge current at this time is still gradually decreasing.

[0153] Wherein the first preset condition refers to: the difference between the voltage of the first power supply and the pre-charge voltage is located in the range of [5% of the voltage of the first power supply, 20% of the voltage of the first power supply].

[0154] At this time, if the difference between the voltage of the first power supply and the pre-charge voltage satisfies a second preset condition, the first drive circuit 305 is controlled to be turned off to realize the turn-off of the first switch tube unit 306 to make the pre-charge of the pre-charge circuit complete, and the second drive circuit 307 is controlled to be turned on to realize the turn-on of the switch array 308 to make the load 701 enter a normal working state.

[0155] The second preset condition refers to a case that the difference between the voltage of the first power supply and the pre-charge voltage is less than 5% of the voltage of the first power supply.

[0156] The second drive circuit 307 is controlled to be turned on, that is, the control circuit can control the second control signal h2 to output a high-level signal, and the high-level signal makes the second drive circuit 307 turned on. After the second drive circuit 307 is turned on, the output end outputs the high-level second control signal h2. Since the second switch tube MOS2, the third switch tube MOS3 and the fourth switch tube MOS4 in the switch array 308 are all N-type MOS tubes, they have the characteristics of “high-level turn-on and low-level turn-off”. Therefore, the high-level second control signal h2 can make the second switch tube MOS2, the third switch tube MOS3 and the fourth switch tube MOS4 all in the turn-on state to realize the turn-on of the switch array 308. At this time, the load current can pass through the low-impedance switch array 308, and the load 701 enters a normal working state.

[0157] As another optional embodiment, when the pre-charge current drops to the lower limit Ith2 of the pre-charge current threshold, the duty cycle of the first control signal h1 can not be adjusted, and the current duty cycle is maintained. Or in the case that the pre-charge current is less than the pre-charge current threshold, if the difference between the voltage of the first power supply and the pre-charge voltage is greater than 5% of the voltage of the first power supply at this time, the duty cycle of the first control signal h1 can not be adjusted, and the current duty cycle is maintained.

[0158] It can be understood that by using the pre-charge circuit with closed-loop feedback control, dynamic pre-charge management of high-risk loads is realized, the inrush current at the power-on moment is effectively limited, the possibility of arc generation is reduced, the charging efficiency is improved, and the stable operation of the system is ensured.

[0159] The protection strategy of the filter absorption circuit in the case that the risk level of the load is a low-risk level will be introduced below.

[0160] In an embodiment, the protection strategy of the filter absorption circuit can include a resistance-capacitance filter circuit.

[0161] The resistance-capacitance filter circuit can be the resistance-capacitance filter circuit as described above, or can include a resistor and a capacitor, the resistor and the capacitor being connected in series, the other end of the resistor being connected to a power supply, the other end of the capacitor being connected to a ground, and the load being connected in parallel to the two ends of the capacitor. The application does not particularly limit this.

[0162] In another embodiment, the filter absorption circuit can include a resistance-capacitance filter circuit and a transient voltage suppressor. In the case where the filter absorption circuit includes a resistance-capacitance filter circuit and a transient voltage suppressor, it can be the secondary protection unit 202 as described above, which will not be described here.

[0163] It can be understood that by adopting the resistance-capacitance filter circuit or the combination of the resistance-capacitance filter circuit and the transient voltage suppressor, the high-frequency noise and the transient voltage caused by the electric arc can be effectively absorbed, and the simple protection requirement of the low-risk level load can be met, the structure is compact and the cost is low, and it is suitable for large-scale application.

[0164] As another optional embodiment, in some embodiments, as shown in Figure 4 The electric arc discharge protection method provided by the embodiments of the application further includes steps S105 and S106.

[0165] S105, obtaining a configuration parameter of the load.

[0166] In an example, the configuration parameter of the load can be a first configuration parameter of the load.

[0167] The first configuration parameter can include an identifier of the load.

[0168] In another example, the configuration parameter of the load can be a second configuration parameter of the load.

[0169] The second configuration parameter can include an impedance characteristic of a circuit in which the load is located or a relationship between a current phase and a voltage phase of the load.

[0170] It can be understood that the load type of the load can be identified through different configuration parameters of the load, and the flexibility of determining the load type of the load is improved.

[0171] S106, determining a load type of the load based on the configuration parameter of the load.

[0172] The load type includes a capacitive load and an inductive load.

[0173] Exemplarily, the capacitive load can include but is not limited to a capacitor, and the inductive load can include but is not limited to an inductor.

[0174] By determining the load type of the load, the matching of the discharge protection strategy can be more helpful, and the strategy of matching the distributed electric arc absorption circuit for the capacitive load can be matched as much as possible.

[0175] In one example, determining the load type based on the load's configuration parameters can be achieved by statically identifying the load based on its first configuration parameters.

[0176] In another example, determining the load type based on the load's configuration parameters can be achieved by dynamically identifying the load type based on a second configuration parameter.

[0177] This application does not impose any specific limitations on this matter; the following is in conjunction with... Figure 5 Step S106 will be described in detail.

[0178] like Figure 5 As shown, in one embodiment, as in step S106A.

[0179] S106A. Determine the load type based on the load identifier.

[0180] For example, a table mapping identifiers to load types can be pre-set. Different identifiers represent different loads, and each load corresponds to a load type. By collecting the identifier of the load, the identifier is searched in the pre-set table mapping identifiers to load types. Once the identifier is found, the load type of the load corresponding to the identifier can be obtained, and it can be determined whether the load is a capacitive load or an inductive load.

[0181] In another embodiment, as in step S106B.

[0182] S106B. Determine the load type based on the impedance characteristics of the circuit in which the load is located.

[0183] For example, if the impedance changes significantly with frequency, it is an inductive load; if the impedance is close to zero at low frequencies, it is a capacitive load.

[0184] In yet another embodiment, such as step S106C.

[0185] S106C. Determine the load type based on the relationship between the current phase and voltage phase of the load.

[0186] For example, a small current excitation can be applied and the phase difference between the current and voltage can be observed. If the current phase follows the voltage phase, the load is an inductive load; if the current phase leads the voltage phase, the load is a capacitive load.

[0187] It is understood that the solution provided in this application embodiment: identifying load types in multiple ways, distinguishing load types helps to design targeted protection strategies and reduce the risk of arc discharge.

[0188] It can be understood that the arc discharge protection method provided in the embodiments of the present application can realize optimization of arc energy absorption and arc interruption process through multi-stage suppression, active control and dynamic variable impedance, and can ensure the safety and stability of the power distribution system. Compared with the related art, the arc discharge protection method provided in the embodiments of the present application can timely absorb the arc when the arc is detected, clamp the voltage, and timely turn off the power supply, so as to achieve absorption and protection of the arc, and has higher reliability.

[0189] In another embodiment of the present application, a vehicle is provided, comprising a power distribution system and a control circuit, the power distribution system being connected with the control circuit; wherein the power distribution system at least comprises a circuit breaker and a protection circuit, the protection circuit comprising at least one of the following: a centralized arc absorption circuit, a distributed arc absorption circuit and a filter absorption circuit; the control circuit is configured to implement any one of the arc discharge protection methods in the foregoing embodiments.

[0190] Wherein, the detailed introduction about the "centralized arc absorption circuit", "distributed arc absorption circuit" and "filter absorption circuit" can be referred to the related introduction in the foregoing embodiments, and will not be described here.

[0191] The possible implementation of the arc discharge protection method described in one or more of the foregoing embodiments is described as follows.

[0192] The arc discharge protection method provided in the embodiments can be applied to the 48V low-voltage power distribution system of an electric vehicle, and can further absorb and protect the switching transient arc caused by various types of high-power loads of the vehicle.

[0193] The arc discharge protection method provided in the embodiments is specifically as follows:

[0194] Figure 6 The structure diagram of an arc discharge protection system provided in the embodiments of the present application is as follows: Figure 6As shown, the system mainly consists of four parts. The first part is the load classification and identification unit 602, which is used to determine the load status of the vehicle and the power-on logic of the load during power-on and power-off. The second part is the centralized arc processing unit 601, which is used to execute the protection strategy of the centralized arc absorption circuit and is responsible for the passive absorption and corresponding processing strategy of the system arc. The third part is the distributed arc absorption and processing unit 603, which is used to execute the protection strategy of the distributed arc absorption circuit. Different absorption and protection circuits are adopted according to the different arc characteristics generated by different types of loads, and different processing methods are adopted for different levels of loads. The fourth part is the intelligent control monitoring unit 604, which mainly monitors the status of the controller or system, judges based on voltage / current sensor signals, and adopts matching suppression strategies. The 48V load unit 70 is connected to the arc discharge protection system 60 through the 48V load interface on the arc discharge protection system 60. The vehicle control unit 80 is connected to the arc discharge protection system 60 through the communication bus and uploads the status and fault codes of the load through the communication bus.

[0195] A 48V battery is connected to the input terminal of the arc discharge protection system 60 via the main fuse F1. The arc discharge protection system 60 integrates multiple power output channels (corresponding to different loads). Each channel is connected in series with a mechanical relay / contaminator (K1~Kn) and in parallel with a centralized arc absorption circuit. The distributed arc absorption circuit is connected in parallel to the power supply interface of the load, forming an integrated "load-energy absorption terminal" unit with the load.

[0196] like Figure 5 The flowchart shown is a method for determining the load type of a load. The load type is determined by either static configuration identification or dynamic identification.

[0197] The type of load can be identified using a preset load identification (ID), or simply the load identifier. Alternatively, the type of load can be identified by detecting the impedance characteristics of the circuit in which the load is located. For example, measuring the circuit impedance before powering on; if the impedance changes significantly with frequency, it is an inductor; if the impedance is close to zero at low frequencies, it is a capacitor. Alternatively, the type of load can be identified through the current / voltage response curve. For example, after applying a small current excitation, observe the phase difference; inductive load current lags the voltage, while capacitive load current leads the voltage.

[0198] Among them, the method of confirming the type of load by using a preset load ID is called the static configuration identification method; the method of confirming the type of load by detecting the impedance characteristics of the circuit in which the load is located, or by using the current / voltage response curve, is called the dynamic identification method.

[0199] In an alternative embodiment, the risk level of the load can be determined according to the load type, the rated current, and the function of the load. In another alternative embodiment, the risk level of the load can be determined according to the arc energy of the arc. The present embodiment does not make special limitations thereon, and the following will be exemplarily described by taking the determination of the risk level of the load according to the arc energy of the arc as an example.

[0200] wherein the high-risk-level load can be an electric drive and a battery; the medium-risk-level load can be an air conditioner compressor; and the low-risk-level load can be a vehicle lamp.

[0201] wherein the logic strategy of the intelligent control monitoring unit 604 adopts a dynamic cooperative control strategy, and this unit is mainly responsible for monitoring the working conditions of each load and controlling the working of the arc suppression unit based on the load type and the arc characteristics.

[0202] Exemplarily, S1: during the running of the load (especially during the power-on and power-off moments), the loop parameters are collected in real time by the voltage / current sensor, and the contact voltage Vs and the load current Is are collected.

[0203] S2: the arc characteristic signals (such as voltage peak, current mutation rate, and high-frequency oscillation) are extracted, and the voltage change rate (dv / dt) and the current change rate (di / dt) are calculated.

[0204] wherein the voltage change rate can be calculated according to the contact voltage Vs; and the current change rate can be calculated according to the load current.

[0205] S3: the extracted arc characteristic signals are compared with the preset threshold value, and it is judged whether the arc occurs.

[0206] Exemplarily, when dv / dt (i.e. the voltage change rate) > the preset voltage change rate threshold value (such as 50 V / us) and the load current Is > the preset current threshold value (10 A), it is determined that the arc occurs.

[0207] Alternatively, it can also be determined that the arc occurs when the current change rate is greater than the preset current change rate threshold value.

[0208] S4: when the arc occurs, the arc energy Earc is calculated according to the arc duration tarc, the voltage peak Uarc of the arc, and the current peak Iarc of the arc. The calculation formula of the arc energy Earc can refer to formula (1).

[0209] S5: when the arc occurs, the redundant protection (such as high-speed switch opening, energy discharge) is triggered immediately according to the level of the load and the generated arc energy, and different protection strategies are adopted:

[0210] (1) For low-risk level loads, RC filter absorption circuit (i.e. resistance-capacitance filter circuit) or RC filter absorption circuit and transient voltage suppressor filter absorption circuit are used;

[0211] (2) For medium-risk level, centralized arc absorption module is used, at this time the load can be actively limited, the current is reduced, and the load power is adjusted;

[0212] (3) For high-risk level, active and passive intelligent protection scheme (i.e. protection strategy of centralized arc absorption circuit and protection strategy of distributed arc absorption circuit) is used, and the active clamping circuit is turned on at the same time, the switch of the corresponding load is cut off, and the double protection of "energy absorption + power off" is realized.

[0213] S6: Real-time reporting of load status to the vehicle control unit (VCU), uploading fault codes when a fault occurs, and recording event logs for diagnosis.

[0214] As shown in Figure 2 , the protection strategy of the centralized arc absorption circuit is applicable to loads of medium-risk level or high-risk level. The centralized arc absorption circuit includes: active and passive protection + adaptive matching, passive arc energy absorption, and voltage clamping to within 60V. The centralized arc absorption circuit mainly includes a varistor MOV (i.e. a first protection unit 201), a first transient voltage suppressor TVS1 and an RC absorption circuit (i.e. a resistance-capacitance filter circuit), and a MOS clamping circuit (i.e. a clamping unit 203), forming a two-stage arc protection and absorption circuit.

[0215] The protection strategy of the centralized arc absorption circuit includes: in the case where the risk level of the load is medium-risk level or high-risk level: the varistor MOV1 is connected in parallel across the input power supply or the connector, used for clamping surge voltage; TVS1 and RC absorption circuit (i.e. secondary protection unit 202) are used to suppress high-frequency arc energy; MOS active clamping circuit is turned on quickly by intelligent control unit when arc occurs, forcing the contact voltage to be pulled down to a safe threshold (e.g. less than 60V).

[0216] As shown in Figure 3As shown, the protection strategy of the distributed arc absorption circuit is suitable for high-risk level loads, and the protection strategy of the distributed arc absorption circuit is composed of a dynamic pre-charge branch with an MOSFET array (i.e., the switch array 308), a current sampling circuit (i.e., the resistance sampling unit 303), a voltage detection circuit 301, a current limiting resistance unit 304, a MOS drive 1 (i.e., the first drive circuit 305), a MOS drive 2 (i.e., the second drive circuit 307), a first switch tube MOS1 (i.e., the first switch tube unit 306), and a pre-charge capacitor unit (i.e., the load 701). The control unit dynamically adjusts the equivalent resistance of the first switch tube MOS1 by modulating the duty cycle of the PWM signal (i.e., the first control signal h1), thereby realizing closed-loop control of the pre-charge current. This scheme is suitable for loads with large-capacitance input terminals such as motor controllers, DC / DC converters, and supercapacitor modules.

[0217] The protection strategy of the distributed arc absorption circuit first uses a hybrid MOSFET array in series and parallel to balance low resistance and high voltage resistance. The MOSFET array is composed of multiple low-resistance MOSFETs in parallel. Second, the control circuit uses proportional (P) -integral (I) control, fuzzy control, or adaptive control algorithms to realize closed-loop dynamic adjustment of the PWM. Finally, the current sampling circuit and the voltage sampling circuit form a double-loop feedback control system to realize real-time monitoring and adjustment of the pre-charge current and the pre-charge voltage.

[0218] As shown in Figure 9 The protection strategy of the distributed arc absorption circuit includes the following steps:

[0219] S901, identify the working state and requirements of the load, and set the pre-charge current threshold.

[0220] S902, set the PWM duty cycle.

[0221] Setting the PWM duty cycle means setting the duty cycle of the first control signal h1. An initial PWM duty cycle can be set.

[0222] S903, detect the pre-charge current and the pre-charge voltage.

[0223] S904, determine whether the pre-charge current is less than the pre-charge current threshold. If yes, execute step S905, if no, execute step S911.

[0224] S905, calculate the difference between the power supply voltage and the pre-charge voltage.

[0225] S906, determine whether the first preset condition is met. If yes, execute step S907, if no, execute step S908.

[0226] Wherein, it is judged whether the difference between the power supply voltage and the pre-charge voltage satisfies the first preset condition.

[0227] Wherein, the first preset condition refers to 5%*the voltage of the first power supply ≤ ≤20%*the voltage of the first power supply.

[0228] Wherein, ΔV represents the difference between the power supply voltage and the pre-charge voltage.

[0229] S907, increase the PWM duty ratio and speed up the pre-charge.

[0230] S908, judge whether the second preset condition is satisfied, if yes, execute step S909, if not, execute step S910.

[0231] Wherein, it is judged whether the difference between the power supply voltage and the pre-charge voltage satisfies the second preset condition.

[0232] Wherein, the second preset condition refers to, <5%*the voltage of the first power supply.

[0233] S909, close the pre-charge circuit and open the main circuit.

[0234] S910, satisfy the third preset condition.

[0235] Wherein, the third preset condition refers to, >20%*the voltage of the first power supply.

[0236] When the third preset condition is satisfied, the PWM duty ratio can be maintained unchanged and step S905 is continuously executed.

[0237] S911, reduce the PWM duty ratio and reduce the pre-charge current.

[0238] In an embodiment, the strategy of the distributed arc absorption circuit can be divided into three stages: initial current limiting stage, dynamic acceleration stage and full conduction stage based on the arc protection method strategy at the power-on moment of the capacitive load. In this process, the control circuit adjusts the PWM duty ratio in real time to ensure that the pre-charge current does not exceed the pre-charge current threshold, and at the same time, the pre-charge voltage is smoothly raised to the power supply voltage (i.e. the voltage of the first power supply V1) level.

[0239] It should be noted that the pre-charge voltage smoothly rising to the power supply voltage level also means that the voltage across the load also smoothly rises to the power supply voltage level.

[0240] Wherein, the initial current limiting stage is also called passive pre-charge stage, specifically:

[0241] A1: system power on, at this time MOS drive 1 and MOS drive 2 low level, the first switch tube MOS1~fourth switch tube MOS4 are all off; At this time the current through the first power supply V1, load 701, sampling resistor Rs and current limiting resistor R22 to ground GND.

[0242] A2: due to the resistance of the current limiting resistor R22 is large, the initial surge current will be limited in a very safe low level.

[0243] A3: the current detection device 90 will detect an initial peak current, and then the current will gradually decrease with the charging of the load capacitor, which is the pre-charge current.

[0244] Among them, the dynamic acceleration stage is also called active pre-charge stage, specifically:

[0245] B1, the control circuit can dynamically adjust the range of pre-charge current threshold according to the load working state and demand, set the upper limit of pre-charge current threshold as I th1 , the lower limit of pre-charge current threshold as I th2 .

[0246] B2, when the control circuit detects that the current decreases from the initial peak to the upper limit of pre-charge current threshold Ith1 through the current detection device 90, the duty cycle of PWM signal is automatically reduced to reduce the pre-charge current; At this time, the control circuit starts to control MOS drive 1 and outputs PWM signal with reduced duty cycle; At this time, the total resistance of pre-charge circuit is R 总 =R22 / / R eq（MOS1） . Among them, R eq（MOS1） is the equivalent resistance of the first switch tube MOS1, according to the conduction degree of MOS tube, the equivalent resistance is different, see Figure 7 .

[0247] B3: the control circuit detects the pre-charge current to form a closed loop control system, dynamically adjusts the duty cycle of MOS drive 1.

[0248] B4: the control circuit detects the pre-charge voltage and adjusts the PWM duty cycle according to the relationship between the pre-charge voltage and the power supply voltage (i.e. the voltage of the first power supply V1); When the difference between the power supply voltage and the pre-charge voltage is in the range of [power supply voltage*5%, power supply voltage*20%], the control circuit gradually increases the PWM duty cycle to speed up the charging speed; At this time, the pre-charge current gradually decreases.

[0249] Among them, the full conduction stage is specifically:

[0250] C1: when the control circuit detects that the pre-charge current decreases to the lower limit of pre-charge current threshold I th2 , maintain this pre-charge current for pre-charge, that is, maintain the PWM duty cycle unchanged.

[0251] C2: Simultaneously detect the pre-charge voltage, when the difference between the power supply voltage and the pre-charge voltage is less than 5% of the power supply voltage, the control circuit controls the MOS drive 1 to be turned off, and outputs a low level, and the pre-charge is completed.

[0252] C3: The control circuit controls the MOS drive 2 to output a high level, turns on the second switch MOS2, the third switch MOS3 and the fourth switch MOS4, and the load current passes through the MOSFET array with low impedance, and the system enters a normal working mode.

[0253] In another optional embodiment, the distributed arc absorption circuit can also adopt a traditional TVS array + RC filter absorption scheme, which is mainly used for low-risk level loads. The circuit is configured at the load power supply end interface to realize basic protection.

[0254] In summary, the embodiment provides an arc discharge protection method. On the one hand, the arc discharge problem of the 48V power distribution system can be solved by classifying and identifying the load type (inductive / capacitive), designing the inhibition strategy (reverse voltage inhibition for inductive load and surge current limitation for capacitive load) in a targeted manner, and combining real-time arc detection and emergency handling mechanism. The touch point damage, device failure and safety hazard problems caused by arc during power-on and power-off of the 48V power distribution system are effectively solved, and cost control and system integration are taken into account.

[0255] On the other hand, it can also be applied to 12V and 48V hybrid power distribution network architecture to form a systematic arc protection method, realize active and passive protection + system-level monitoring method, and solve the arc problem caused by frequent switching of electric vehicles in multi-load systems through four main unit modules for hierarchical design of power distribution systems.

[0256] Thirdly, a distributed arc absorption is adopted to build an active and passive protection mechanism to absorb the arc generated during power-on and power-off of inductive loads. Passive absorption: parallel TVS tube and RC absorption network at the power supply end to quickly clamp voltage peaks; active protection: replace mechanical relays with electronic switches such as MOS tubes or insulated gate bipolar transistors (IGBT) to realize controlled disconnection and avoid mechanical contact arc, and add a large-capacitance pre-charge circuit at the front end of the load to prevent the generation of electric sparks due to excessive transient current during power-on and power-off; through adaptive adjustment of load capacitance size, it can be flexibly applied in different scenarios, and the fast and safe dynamic pre-charge scheme

[0257] In the fourth aspect, a dynamic coordination control method is adopted to dynamically adjust the arc absorption strategy in combination with the load type, risk level and arc energy, and when the arc occurs, the intelligent control unit first adopts the distributed arc absorption module, simultaneously adopts the centralized arc absorption unit, triggers the clamping circuit according to the risk level, and forms the intelligent coordination control of “distributed rapid energy absorption + centralized deep arc suppression”.

[0258] In the fifth aspect, for the gradually popularized high-power loads such as motor controllers, DC / DC converters and super capacitor modules, a dynamic pre-charging scheme of a switch array is adopted, the equivalent resistance of the first switch MOS1 is adjusted through PWM, and a three-stage pre-charging mode is realized in combination with the current-voltage double-loop control, so as to shorten the pre-charging time and simultaneously make the load voltage smoothly rise to the power supply voltage level.

[0259] In the sixth aspect, a design for prevention is adopted, a pilot needle is designed, the plug-in mode of the connector is optimized, and the creepage distance of the printed circuit board is considered during the design, and the grounding design is good.

[0260] It should be noted that although the steps of the method in the present application are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in this specific order, or that all the steps shown must be performed to achieve the desired result. In addition or alternatively, some steps can be omitted, a plurality of steps can be combined into one step, and / or one step can be divided into a plurality of steps, etc.; or the steps in different embodiments can be combined into a new technical solution.

[0261] It should be understood that the "one embodiment" or "an embodiment" or "some embodiments" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, "in one embodiment" or "in an embodiment" or "in some embodiments" appearing throughout the specification does not necessarily mean the same embodiment. In addition, these specific features, structures or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in various embodiments of the present application, the size of the serial number of the above processes does not mean the execution order, and the execution order of the processes should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application. The serial number of the above embodiments of the present application is only for description, not representing the advantages and disadvantages of the embodiments. The above description of each embodiment tends to emphasize the differences between each embodiment, and the same or similar parts can be referred to each other. For the sake of brevity, this paper will not repeat here.

[0262] The term "and / or", used in the context of the present application, should be interpreted as "and / or", only as a transitional phrase, not as a limitation, unless expressly so defined by the claim language. For example, in the phrase "A and / or B" A and B represent separate entities--a single entity, or multiple entities. These entities can or can not be mutually exclusive, unless more restrictions are explicitly stated in the claim language.

[0263] It should be noted that, in the present document, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0264] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other manners. The above described embodiments are merely exemplary, and the module division is merely a logical function division, and there can be another division manner for the actual implementation, for example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the components shown or discussed can be indirect coupling or communication connection through some interfaces, devices, or modules, and can be electrical, mechanical, or in other forms.

[0265] The modules described above as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules; they can be located in one place, or distributed on multiple network units; and some or all of the modules can be selected according to actual needs to achieve the purpose of the embodiments.

[0266] In addition, each functional module in each embodiment of the present application can be integrated into one processing unit, or each module can be a separate unit, or two or more modules can be integrated into one unit; the integrated module can be realized in the form of hardware or in the form of hardware plus software functional unit.

[0267] The methods disclosed in the several method embodiments provided by the present application can be combined arbitrarily without conflict, to obtain new method embodiments.

[0268] The features disclosed in the several product embodiments provided by the present application can be combined arbitrarily without conflict, to obtain new product embodiments.

[0269] The features disclosed in several method or device embodiments of the present application can be arbitrarily combined, without conflict, to form new method embodiments or device embodiments.

[0270] The above only describes the embodiments of the present application, and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement and improvement made within the spirit and scope of the present application shall be included in the protection scope of the present application.

Claims

1. An electric arc discharge protection method, characterized in that, The method comprises the following steps: During the load operation, an arc characteristic signal generated by the load is acquired; In the case that the arc characteristic signal indicates that the power distribution system generates an arc, arc energy is calculated based on the arc characteristic signal; According to the arc energy, a risk level of the load is determined, in the case that the risk level of the load is a high risk level, it is determined that the protection strategy comprises a protection strategy of a centralized arc absorption circuit and a protection strategy of a distributed arc absorption circuit; in the case that the risk level of the load is a medium risk level, it is determined that the protection strategy comprises the protection strategy of the centralized arc absorption circuit; in the case that the risk level of the load is a low risk level, it is determined that the protection strategy comprises a protection strategy of a filter absorption circuit; Based on the protection strategy, arc discharge protection is performed on the power distribution system; The arc energy is calculated based on the arc characteristic signal, comprising: The voltage peak value of the arc and the current peak value of the arc in the arc characteristic signal are acquired; The duration of the arc is acquired; The voltage peak value of the arc and the current peak value of the arc are integrated within the duration to obtain the arc energy; According to the arc energy, the risk level of the load is determined, comprising: In the case that the arc energy is in a first set range, it is determined that the risk level of the load is a low risk level; In the case that the arc energy is in a second set range, it is determined that the risk level of the load is a medium risk level; In the case that the arc energy is in a third set range, it is determined that the risk level of the load is a high risk level; The upper limit of the first set range is less than the lower limit of the second set range; the upper limit of the second set range is less than the lower limit of the third set range.

2. The method of arc discharge protection according to claim 1, characterized in that, The arc characteristic signal generated by the load is acquired, comprising: Load current signals and contact voltage signals in the power distribution system are collected; The contact voltage signals are subjected to feature extraction to obtain the voltage peak value of the arc and the voltage change rate; The load current signals are subjected to feature extraction to obtain the current peak value of the arc and the current change rate; According to at least one of the voltage peak value of the arc, the voltage change rate, the current peak value of the arc and the current change rate, the arc characteristic signal is determined.

3. The method of arc discharge protection according to claim 2, characterized in that, The method further comprises: In the case that the current change rate is greater than a preset current change rate threshold, it is determined that the arc characteristic signal indicates that the power distribution system generates an arc; or, In the case that the voltage change rate is greater than a preset voltage change rate threshold and the amplitude of the load current signal is greater than a preset current threshold, it is determined that the arc characteristic signal indicates that the power distribution system generates an arc.

4. The method of arc discharge protection according to claim 1, characterized in that, The centralized arc absorption circuit comprises a first protection unit, a second protection unit and a clamping unit, and the protection level of the second protection unit is higher than that of the first protection unit; the first protection unit is connected in parallel across the input power supply or connector; the input side of the second protection unit is connected to the output side of the first protection unit, and the output side of the second protection unit is connected to the input side of the clamping unit; the output side of the clamping unit is connected in parallel to the load; wherein: In the case that the risk level of the load is a high risk level or a medium risk level, the protection strategy of the centralized arc absorption circuit comprises: The first protection unit is used for clamping the surge voltage of the input power supply or connector; The second protection unit is used for absorbing the voltage spikes missed by the first protection unit and suppressing high-frequency arc energy; The clamping unit is used for turning on the first transistor in the case of arc generation, so that the contact voltage of the circuit breaker in the power distribution system drops to a safety threshold.

5. The method of arc discharge protection according to claim 1, characterized in that, The distributed arc absorption circuit comprises a pre-charge circuit, and the pre-charge circuit comprises a first switch tube unit, a first drive circuit, a switch array and a second drive circuit; The first end of the load is connected to a first power supply, the second end of the load is connected to the first end of the first switch tube unit, the second end of the first switch tube unit is grounded, the control end of the first switch tube unit is connected to the output end of the first drive circuit, and the input end of the first drive circuit is used for receiving a first control signal; the control end of the switch array is connected to the output end of the second drive circuit; In the case that the risk level of the load is high, the strategy of the distributed arc absorption circuit comprises: When the power distribution system is powered on, the first switch tube unit and the switch array are controlled to be in an off state; According to the working state and demand of the load, a pre-charge current threshold is determined; In the case that the collected pre-charge current is greater than or equal to the pre-charge current threshold, the duty cycle of the first control signal is reduced, and the first drive circuit outputs the first control signal with the reduced duty cycle to control the on or off time of the first switch tube unit, so that the pre-charge current is less than the pre-charge current threshold; In the case that the pre-charge current is less than the pre-charge current threshold, and the difference between the voltage of the first power supply and the collected pre-charge voltage satisfies a first preset condition, the duty cycle of the first control signal is increased to improve the charging speed of the pre-charge circuit; In the case that the pre-charge current is less than the pre-charge current threshold, and the difference between the voltage of the first power supply and the pre-charge voltage satisfies a second preset condition, the first switch tube unit is controlled to be off by the first drive circuit, so that the pre-charge of the pre-charge circuit is completed; and the switch array is controlled to be on by the second drive circuit, so that the load enters a normal working state.

6. The method of arc discharge protection according to claim 4, characterized in that, The filter absorption circuit comprises a resistance-capacitance filter circuit; Alternatively, the filter absorption circuit comprises the resistance-capacitance filter circuit and a transient voltage suppressor.

7. The method of arc discharge protection according to any of claims 1 to 6, characterized in that The method further comprises: obtaining a configuration parameter of the load; determining a load type of the load based on the configuration parameter of the load; wherein the load type comprises a capacitive load and an inductive load.

8. The method of arc discharge protection according to claim 7, characterized in that, The configuration parameter of the load comprises: an identifier of the load; or an impedance characteristic of a loop in which the load is located; or a relationship between a current phase and a voltage phase of the load.

9. A vehicle characterized by comprising: A power distribution system and a control circuit, the power distribution system being connected to the control circuit; wherein the power distribution system comprises at least a circuit breaker and a protection circuit, the protection circuit comprising at least one of: a centralized arc absorption loop, a distributed arc absorption loop, and a filter absorption loop; The control circuit is configured to implement the method of any one of claims 1-8.

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