CN116316409A

CN116316409A - Circuit protection method, circuit protection device, storage medium and vehicle power supply system

Info

Publication number: CN116316409A
Application number: CN202111586033.5A
Authority: CN
Inventors: 洪嫣
Original assignee: Shanghai Linyun Technology Co ltd
Current assignee: Shanghai Linyun Technology Co ltd
Priority date: 2021-12-20
Filing date: 2021-12-20
Publication date: 2023-06-23

Abstract

The invention provides a circuit protection method and device, a computer readable storage medium and a vehicle power supply system. The circuit protection method comprises the following steps: obtaining a measure of current flowing through the protected circuit; comparing the current measurement to a rated current threshold and a short circuit current threshold of the protected circuit; cutting off the protected circuit to perform instant short-circuit protection in response to a comparison result that the current measurement value is greater than the short-circuit current threshold value; and determining the time for cutting off the protected circuit according to the current measured value to carry out delay protection according to the comparison result that the current measured value is larger than the rated current threshold value but smaller than the short-circuit current threshold value. By executing the steps, the circuit protection method can distinguish protection aiming at different fault conditions, so that the reliability and the instantaneity of protection are improved, and the misjudgment probability of protection is reduced.

Description

Circuit protection method, circuit protection device, storage medium and vehicle power supply system

Technical Field

The present invention relates to a vehicle power supply technology, and more particularly, to a circuit protection method, a circuit protection device, a computer-readable storage medium, and a vehicle power supply system.

Background

A fuse is a conventional circuit protection device that fuses with heat generated by a current when the current exceeds a prescribed threshold, thereby breaking a circuit to protect a circuit harness and a load to which it is connected. As an improved technology of the fuse, the electronic fuse (eFuse) further provides the functions of quick power-off, reverse current protection, reverse polarity protection and circuit reset, and can provide more stable and reliable working voltage to the electronic control unit (Electronic Control Unit, ECU) at the rear end, thereby reducing the overall protection cost of the rear-end ECU and solving the problem of difficult replacement of the conventional fuse.

However, as an emerging circuit protection technology, electronic fuses (eFuses) are also being controlled in a relatively deficient manner, primarily by determining whether the circuit needs to be cut based on whether the current reaches a preset threshold. In such a single protection scheme, if the current threshold is set too low, a fault misjudgment is likely to occur, thereby affecting the normal operation of the corresponding function of the vehicle. Otherwise, if the current threshold is set too high, failure and omission are easy to occur, so that safe operation of a vehicle power supply line and a load is difficult to ensure. Therefore, the single protection scheme generally has the problem that the safety and the judgment accuracy are difficult to be simultaneously achieved, and is not beneficial to the further development and popularization of the electronic fuse.

In order to overcome the above-mentioned drawbacks of the prior art, a more sophisticated vehicle power supply technology is needed in the art, which is used for distinguishing and protecting against different fault conditions, so as to improve the reliability and instantaneity of protection and reduce the misjudgment probability of protection.

Disclosure of Invention

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

In order to overcome the above-mentioned drawbacks of the prior art, the present invention provides a circuit protection method, a circuit protection device, a computer-readable storage medium, and a vehicle power supply system.

Specifically, the circuit protection method provided according to the first aspect of the present invention includes the following steps: obtaining a measure of current flowing through the protected circuit; comparing the current measurement to a rated current threshold and a short circuit current threshold of the protected circuit; cutting off the protected circuit to perform instant short-circuit protection in response to a comparison result that the current measurement value is greater than the short-circuit current threshold value; and determining the time for cutting off the protected circuit according to the current measured value to carry out delay protection according to the comparison result that the current measured value is larger than the rated current threshold value but smaller than the short-circuit current threshold value. By executing the steps, the circuit protection method can select a proper mode from a plurality of protection modes such as short-circuit protection, delay protection and the like according to the current measured value to carry out circuit protection, thereby improving the reliability and instantaneity of protection and reducing the misjudgment probability of protection.

Further, in some embodiments of the present invention, the step of determining the timing of cutting off the protected circuit for delay protection based on the current measurement may include: performing an integration operation on the current measurement value to simulate the heating value of the protected circuit; and responsive to the heating value reaching a configured heating value threshold, cutting off the protected circuit to perform heating value-based delay protection.

Further, in some embodiments of the present invention, the step of determining the timing of cutting off the protected circuit according to the current measurement value for delay protection may further include: acquiring a temperature measurement of the protected circuit; and determining the heat threshold based on the temperature measurement and a temperature upper limit of the protected circuit.

Further, in some embodiments of the present invention, the step of determining the timing of cutting off the protected circuit for delay protection based on the current measurement may include: acquiring a change curve of a thermal protection current threshold value relative to duration, wherein the thermal protection current threshold value on the change curve is calculated and determined according to the configured thermal threshold value; counting the duration of time that the current measurement value is greater than the rated current threshold value; determining the thermal protection current threshold according to the duration and the change curve; and responsive to the current measurement being greater than the thermal protection current threshold, switching off the protected circuit for thermal-based delay protection.

Further, in some embodiments of the present invention, the step of determining the timing of cutting off the protected circuit for delay protection based on the current measurement may include: comparing the current measurement to an overload current threshold of the protected circuit, wherein the overload current threshold is greater than the rated current threshold and less than the short circuit current threshold; in response to a comparison that the current measurement is greater than the overload current threshold, counting a duration that the current measurement is greater than the overload current threshold; and responsive to the duration reaching a configured overload time threshold, switching off the protected circuit for delay protection based on a delay time.

Further, in some embodiments of the present invention, before the step of performing the delay protection, the circuit protection method may further include the steps of: load information of the protected circuit is obtained; in response to the load information indicating that the protected circuit has an inductive load characteristic, employing the heat generation-based delay protection; and employing the delay time based delay protection in response to the load information indicating that the protected circuit has resistive load characteristics.

Further, in some embodiments of the present invention, before the step of performing the delay protection, the circuit protection method may further include the steps of: acquiring the rated current threshold of the protected circuit; and determining the short-circuit current threshold and/or the overload current threshold of the protected circuit according to the load information and the rated current threshold of the protected circuit.

Further, in some embodiments of the present invention, the circuit protection method may further include the steps of: in response to the protected circuit being cut off, a fault report is generated according to a protection mode that cuts off the protected circuit.

Further, the above-described circuit protection device provided according to the second aspect of the present invention includes a current detection unit, an execution unit, and a control unit. The control unit is connected with the current detection unit and the execution unit and is configured to: acquiring, via the current detection unit, a measured value of current flowing through the protected circuit; comparing the current measurement to a rated current threshold and a short circuit current threshold of the protected circuit; in response to a comparison result that the current measurement value is greater than the short-circuit current threshold value, cutting off the protected circuit through the execution unit so as to conduct instant short-circuit protection; and determining the time for cutting off the protected circuit according to the current measured value to carry out delay protection through the execution unit in response to the comparison result that the current measured value is larger than the rated current threshold value but smaller than the short-circuit current threshold value. By adopting the configurations, the circuit protection device can select a proper mode from a plurality of protection modes such as short-circuit protection, delay protection and the like according to the current measured value to carry out circuit protection, thereby improving the real-time performance of protection and reducing the misjudgment probability of protection.

Further, in some embodiments of the present invention, the circuit protection device may further include a communication unit. The control unit is connected to the control terminal via the communication unit, and is further configured to: obtaining, via the communication unit, a protection policy implemented on the protected circuit from the control terminal, wherein the protection policy indicates a short circuit protection mode and at least one delay protection mode; and/or obtaining one or more of a rated current threshold, a short circuit current threshold, a heat threshold, a temperature upper limit, a thermal protection current threshold change curve with respect to duration, an overload current threshold, and an overload time threshold of the protected circuit from the control terminal via the communication unit; and/or obtaining a temperature measurement of the protected circuit from the control terminal via the communication unit; and/or sending a prompt message that the protected circuit is cut off and/or a fault report indicating a protection mode of cutting off the protected circuit to the control terminal via the communication unit.

Further, the above-described computer-readable storage medium according to the third aspect of the present invention has stored thereon computer instructions. The computer instructions, when executed by a processor, implement the above-mentioned circuit protection method provided by the first aspect of the present invention. By implementing the circuit protection method, the computer readable storage medium can select a proper mode from a plurality of protection modes such as short-circuit protection, delay protection and the like according to the current measured value to carry out circuit protection, thereby improving the reliability and instantaneity of protection and reducing the misjudgment probability of protection.

Further, the above-described vehicle power supply system according to the fourth aspect of the invention is provided, in which at least one of the above-described circuit protection devices according to the second aspect of the invention is provided. By configuring the circuit protection device, the vehicle power supply system can select a proper mode from a plurality of protection modes such as short-circuit protection, delay protection and the like according to the current measured value to carry out circuit protection, thereby improving the reliability and instantaneity of protection and reducing the misjudgment probability of protection.

Drawings

The above features and advantages of the present invention will be better understood after reading the detailed description of embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily to scale and components having similar related features or characteristics may have the same or similar reference numerals.

Fig. 1 illustrates an architectural diagram of a circuit protection device provided in accordance with some embodiments of the present invention.

Fig. 2 illustrates a flow diagram of a circuit protection method provided in accordance with some embodiments of the invention.

Fig. 3 illustrates a schematic diagram of a thermal protection current threshold versus duration curve provided in accordance with some embodiments of the present invention.

Fig. 4 illustrates an architectural diagram of a circuit protection device provided in accordance with some embodiments of the present invention.

Fig. 5 illustrates a circuit schematic of a vehicle power supply system provided in accordance with some embodiments of the invention.

Fig. 6 illustrates a flow diagram of a circuit protection method provided in accordance with some embodiments of the invention.

Fig. 7 illustrates a schematic diagram of current waveforms of an inductive load provided in accordance with some embodiments of the present invention.

Fig. 8 illustrates a current waveform schematic of a resistive load provided in accordance with some embodiments of the present invention.

Fig. 9 illustrates an architectural diagram of a circuit protection device provided in accordance with some embodiments of the present invention.

Detailed Description

Further advantages and effects of the present invention will become apparent to those skilled in the art from the disclosure of the present specification, by describing the embodiments of the present invention with specific examples. While the description of the invention will be presented in connection with a preferred embodiment, it is not intended to limit the inventive features to that embodiment. Rather, the purpose of the invention described in connection with the embodiments is to cover other alternatives or modifications, which may be extended by the claims based on the invention. The following description contains many specific details for the purpose of providing a thorough understanding of the present invention. The invention may be practiced without these specific details. Furthermore, some specific details are omitted from the description in order to avoid obscuring the invention.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

It will be understood that, although the terms "first," "second," "third," etc. may be used herein to describe various elements, regions, layers and/or sections, these elements, regions, layers and/or sections should not be limited by these terms and these terms are merely used to distinguish between different elements, regions, layers and/or sections. Accordingly, a first component, region, layer, and/or section discussed below could be termed a second component, region, layer, and/or section without departing from some embodiments of the present invention.

As described above, as an emerging circuit protection technology, the control technology of electronic fuses (efuses) is also deficient, and it is mainly determined whether or not a circuit needs to be cut according to whether or not a current reaches a preset threshold. In such a single protection scheme, if the current threshold is set too low, a fault misjudgment is likely to occur, thereby affecting the normal operation of the corresponding function of the vehicle. Otherwise, if the current threshold is set too high, failure and omission are easy to occur, so that safe operation of a vehicle power supply line and a load is difficult to ensure. Therefore, the single protection scheme generally has the problem that the safety and the judgment accuracy are difficult to be simultaneously achieved, and is not beneficial to the further development and popularization of the electronic fuse.

In order to overcome the defects in the prior art, the invention provides a circuit protection method, a circuit protection device, a computer readable storage medium and a vehicle power supply system, which can select a proper mode from a plurality of protection modes such as short-circuit protection, delay protection and the like according to a current measured value to perform circuit protection, thereby improving the real-time performance of the protection and reducing the misjudgment probability of the protection.

In some non-limiting embodiments, the above-mentioned circuit protection method provided by the first aspect of the present invention may be implemented by the above-mentioned circuit protection device provided by the second aspect of the present invention. The circuit protection device may be configured in a main power supply loop of a vehicle power supply system and/or in a power supply branch where at least one circuit load is located, and by implementing the above circuit protection method provided in the first aspect of the present invention, the power supply, the wire harness and/or the at least one circuit load connected thereto are protected.

Referring to fig. 1, fig. 1 is a schematic diagram illustrating an architecture of a circuit protection device according to some embodiments of the invention. As shown in fig. 1, the circuit protection device 10 is provided with a current detection unit 11, an execution unit 12, and a control unit 13.

The current detecting unit 11 is provided in the protected circuit for collecting a measured value of a current flowing through the protected circuit as a data basis for determining whether the protected circuit needs to be cut off. The current detection unit 11 includes, but is not limited to, a current detection element such as a sampling resistor, a fluxgate current sensor, a hall current sensor, or the like. In some embodiments, if a sampling resistor is used, the current detection unit 11 may first measure the voltage across the sampling resistor and then calculate the current flowing through the protected circuit based on ohm's law. In other embodiments, if a fluxgate current sensor or a hall current sensor is used, the current detection unit 11 may first measure the induced voltage and then calculate the current flowing through the protected circuit based on the principle of electromagnetic induction.

The execution unit 12 is connected in series to the protected circuit for executing operation instructions for switching off the protected circuit and switching on the protected circuit, so as to realize circuit protection and circuit reset operations. The execution unit 12 includes, but is not limited to, semiconductor-type switching devices such as MOSFETs, IGBTs, etc., and inductive switching devices such as relays, the specific type of which may be determined based on the type of load connected and the off-time of the system.

The control unit 13 may be integrated within the circuit protection device 10 and/or configured in the on-board system of the vehicle in the form of hardware elements and/or software programs. The control unit 13 is communicatively connected to the current detection unit 11 to obtain the current measurement value it collects, and to the execution unit 12 to provide operation instructions for switching off the protected circuit and switching on the protected circuit.

Further, the control unit 13 may be provided with a memory and a processor. The memory includes, but is not limited to, the above-described computer-readable storage medium provided by the third aspect of the present invention, having stored thereon computer instructions. The processor is coupled to the memory and configured to read and execute computer instructions stored on the memory to implement the above-described circuit protection method provided in the first aspect of the present invention.

The working principle of the above-described circuit protection device will be described below in connection with some embodiments of the circuit protection method. It will be appreciated by those skilled in the art that these examples of circuit protection methods are merely some non-limiting embodiments provided by the present invention, and are intended to clearly illustrate the main concepts of the present invention and to provide some embodiments that are convenient for public implementation, and are not intended to limit the overall functionality or the overall manner of operation of the circuit protection device. Similarly, the circuit protection device is only a non-limiting embodiment provided by the present invention, and does not limit the implementation subject of each step in the circuit protection methods.

Referring to fig. 1 and fig. 2 in combination, fig. 2 is a flow chart illustrating a circuit protection method according to some embodiments of the invention.

As shown in fig. 1 and 2, in the process of protecting the wire harness, the power supply and/or the load of the protected circuit, the control unit 13 may first obtain the measured value I of the current flowing through the protected circuit in real time via the current detection unit 11, and compare the obtained measured value I of the current with the rated current threshold value I of the protected circuit _normal Short-circuit current threshold I _short A comparison is made to determine if the protected circuit needs to be cut off and to determine the circuit protection mode that needs to be performed.

In some embodiments, the nominal current threshold I _normal Short circuit current threshold I _short And the protection strategy of the circuit protection device 10, may be preconfigured into the circuit protection device 10 prior to loading the circuit protection device 10. The protection policy indicates a plurality of circuit protection modes supported by the circuit protection device 10, including, but not limited to, a short circuit protection mode that immediately cuts off the circuit, and one or more delay protection modes. The control unit 13 can obtain the protection strategy directly from the local memory and obtain the preset rated current threshold value I _normal Short-circuit current threshold I _short And comparing the current measured value I with the acquired current measured value I to determine the range section of the current measured value I. Then, the control unit 13 may select at least one appropriate protection mode from among the various protection modes indicated by the protection policy according to the range section in which the current measurement value I is located, to perform circuit protection.

For example, in response to the current measurement I being less than or equal to the rated current threshold I _normal (i.e. I<I _normal ) The control unit 13 may determine that no fault has occurred in the protected circuit. At this point, the control unit 13 may keep the execution unit 12 closed to maintain proper operation of the various power supplies and/or loads on the protected circuit.

For another example, in response to the current measurement I being greater than the short circuit current threshold I _short (i.e. I>I _short ) The control unit 13 can determine that a short-circuit fault has occurred in the protected circuit. At this time, the control unit 13 may immediately disconnect the execution unit 12, and disconnect the protected circuit for immediate short-circuit protection.

For another example, in response to the current measurement I being greater than the rated current threshold I _normal But is less than the short-circuit current threshold I _short (i.e. I _normal <I<I _short ) The control unit 13 may determine that the protected circuit has a circuit abnormality. At this time, the control unit 13 may determine the timing of cutting off the protected circuit based on the current measurement value I, and disconnect the execution unit 12 at the determined cutting timing, thereby performing delay protection on the protected circuit.

By configuring multiple circuit protection modes based on current measurement I, the invention can adopt higher short-circuit current threshold I _short To implement instant short-circuit protection, thereby reducing the misjudgment probability of short-circuit faults. By being at the rated current threshold I _normal Short-circuit current threshold I _short The invention can further combine the subsequent current measured value I' in the protected circuit to judge whether the protected circuit needs to be cut off or not. Thus, the invention can prevent instantThe circuit protection mechanism is triggered by slight overload current, so that the misjudgment probability of circuit protection is reduced, and on the other hand, the continuous thermal damage and overcurrent damage of the overload current to each wire harness, power supply and/or load in the protected circuit can be prevented, so that the reliability and instantaneity of circuit protection are improved.

Further, in some embodiments of the present invention, the above-described delay protection may be implemented based on the heating value Q of each wire harness, power source, and/or load in the protected circuit. Specifically, in response to the current measurement I being greater than the rated current threshold I _normal But is less than the short-circuit current threshold I _short (i.e. I _normal <I<I _short ) The control unit 13 may first perform an integral operation on the current measurement value I (t) acquired in real time to simulate the heating value Q (t) of each wire harness, power supply and/or load in the protected circuit, i.e., Q (t) = ≡i (t) ² ·dt。

Thereafter, the control unit 13 may compare the simulated heating value Q (t) with the pre-configured heating value threshold Q ₀ A comparison is made. If the simulated heating value Q (t) does not reach the preset heating value threshold Q ₀ (i.e., Q (t)<Q ₀ ) The control unit 13 may determine that the above-described circuit abnormality does not temporarily damage each harness, power source and/or load in the protected circuit, thereby keeping the execution unit 12 closed to preferentially ensure normal operation of each power source and/or load. Conversely, if the current measurement I continues to be greater than the nominal current threshold I _normal And the simulated heating value Q (t) reaches the preset heating value threshold Q ₀ Above (i.e. Q (t) is greater than or equal to Q) ₀ ) The control unit 13 may determine that the above-described circuit abnormality will cause damage to the wiring harness, power supply and/or load in the protected circuit. At this time, the control unit 13 will timely disconnect the execution unit 12 to cut off the protected circuit, thereby guaranteeing the safety and reliability of each wire harness, power source and/or load.

Further, in some preferred embodiments, the thermal protection current threshold I may be selected for the integration of the current measurement I (t) _thermal Curve I of the variation with respect to the duration t _thermal -t is substituted. Referring to FIG. 3, FIG. 3 showsA schematic diagram of a thermal protection current threshold versus duration curve is provided according to some embodiments of the present invention.

As shown in FIG. 3, a technician may, at a design stage prior to implementing circuit protection, based on a given thermal threshold Q ₀ Determining a plurality of current values I _i And its corresponding duration t _i Wherein Q is ₀ ＝I _i ·t _i . Then, the technician can select a step curve to connect the coordinate points to obtain the thermal protection current threshold I shown in FIG. 3 _thermal Curve I of the variation with respect to the duration t _thermal -t. At the thermal protection current threshold I _thermal Curve I of the variation with respect to the duration t _thermal At t, each coordinate point (I _i ,t _i ) Corresponding heat productivity Q _i Are all approximately the given heat threshold Q ₀ 。

Alternatively, in other embodiments, the skilled person may also choose to use an inverse proportional function curve f (x) =kx ^-1 +b to fit thermal protection current threshold I _thermal Curve I of the variation with respect to the duration t _thermal T, so that each coordinate point (I _i ,t _i ) Corresponding heat productivity Q _i Are all closer to a given heat threshold Q ₀ 。

Thereafter, in the process of implementing the delay protection based on the heating value Q, the current measured value I is larger than the rated current threshold value I _normal But is less than the short-circuit current threshold I _short (i.e. I _normal <I<I _short ) The control unit 13 may count that the current measurement value I is greater than the rated current threshold value I _normal From the acquired change curve I, again according to the duration t of time t _thermal -determining a corresponding thermal protection current threshold I at t _thermal (t). The control unit 13 can then compare the current measurement I with the thermal protection current threshold I _thermal (t) comparing. If the current measurement I is less than or equal to the thermal protection current threshold I _thermal (t), the control unit 13 may determine that the above-described circuit abnormality does not temporarily cause damage to the respective wiring harnesses, power sources and/or loads in the protected circuit,thereby keeping the execution unit 12 closed to preferentially ensure proper operation of the respective power source and/or load. Conversely, if the current measurement I is greater than the thermal protection current threshold I _thermal (t), the control unit 13 may determine that the above-described circuit abnormality will cause damage to the wiring harness, power supply and/or load in the protected circuit. At this time, the control unit 13 will timely disconnect the execution unit 12 to cut off the protected circuit, thereby guaranteeing the safety and reliability of each wire harness, power source and/or load.

By employing thermal protection current threshold I _thermal Curve I of the variation with respect to the duration t _thermal Instead of the above-mentioned integral operation on the current measurement value I (t), the present invention can further reduce the data processing load of the control unit 13, so as to reduce the hardware configuration requirement of the control unit 13 and promote the real-time performance of circuit protection.

It will be appreciated by those skilled in the art that the above delay protection scheme implemented based on the heating value Q is only a non-limiting embodiment provided by the present invention, and is intended to clearly illustrate the main concept of the present invention and provide a specific scheme for public implementation, not to limit the protection scope of the present invention.

Optionally, in other embodiments, the delay protection may be based on a pre-configured overload current threshold I _large Overload time threshold t ₀ Is implemented. Specifically, in response to the current measurement I being greater than the rated current threshold I _normal But is less than the short-circuit current threshold I _short (i.e. I _normal <I<I _short ) The control unit 13 may further compare the current measurement I with an overload current threshold I of the protected circuit _large A comparison is made. The overload current threshold I _large Greater than the rated current threshold I of the protected circuit _normal And is smaller than its short-circuit current threshold I _short 。

If the current measurement I is less than or equal to the overload current threshold I _large (i.e. I.ltoreq.I) _large ) The control unit 13 may determine that the circuit abnormality described above does not cause damage to the individual harnesses, power sources and/or loads in the protected circuitAnd the overcurrent is damaged, so that the delay protection is performed by adopting the delay protection scheme based on the heating value Q preferentially. Conversely, if the current measurement I is greater than the overload current threshold I _large (i.e. I>I _large ) The control unit 13 may determine that the above-mentioned circuit abnormality is at risk of causing overcurrent damage to the wiring harness, power supply and/or load in the protected circuit.

At this time, the control unit 13 may determine that the current measurement value I is greater than the overload current threshold value I _large Is counted. If the duration t does not reach the pre-configured overload time threshold t ₀ (i.e. t<t ₀ ) The control unit 13 may determine that the above-described circuit abnormality does not temporarily damage each harness, power source and/or load in the protected circuit, thereby keeping the execution unit 12 closed to preferentially ensure normal operation of each power source and/or load. Conversely, if the current measurement I is greater than the overload current threshold I _large The duration t of (2) reaching a pre-configured overload time threshold t ₀ Above (i.e. t.gtoreq.t) ₀ ) The control unit 13 may determine that the above-described circuit abnormality will cause damage to the wiring harness, power supply and/or load in the protected circuit. At this time, the control unit 13 will timely disconnect the execution unit 12 to cut off the protected circuit, thereby guaranteeing the safety and reliability of each wire harness, power source and/or load.

Compared with the delay protection scheme implemented based on the heating value Q, the overload time threshold t ₀ The delay protection scheme is implemented without involving the operation requirement of current integration, so that the delay protection scheme has the advantages of lower data processing load and higher real-time performance, and is more suitable for high current (for example, the rated current threshold I is _normal 2-3 times) the power supply voltage for the circuit in the 2-3 times) mode (e.g.: 10-100 ms), and reliable delay protection. Conversely, compared with the overload time threshold t ₀ The delay protection scheme based on the heating value Q is more suitable for the characteristic that each wire harness, power supply and/or load in the circuit is damaged after accumulating certain heat and can fully consider the actual numerical condition of the super-threshold current delta I (t), thereby being capable of more accurately and reliably preventing each wire harness, power supply and/or loadAnd carrying damage caused by excessive heat accumulation.

Further, in some preferred embodiments, the control unit 13 may also control the overload current threshold I when the current measurement I is greater than the overload current threshold I _large (i.e. I>I _large ) In the case of (1), the above-mentioned threshold value t based on the heating value Q and overload time are operated simultaneously ₀ And cutting off the circuit according to the delay protection mode with the earlier trigger time. By running the two delay protection modes simultaneously, the invention not only can provide rapid large-current protection for each wire harness, power supply and load in the circuit, but also can provide accurate and reliable overheat protection for each wire harness, power supply and load, thereby being capable of considering the accuracy, reliability and instantaneity of circuit protection.

It will be appreciated by those skilled in the art that the circuit protection device 10 shown in fig. 1 is merely a non-limiting embodiment provided by the present invention, and is intended to clearly illustrate the general concepts of the present invention and to provide a specific solution for public implementation, not to limit the scope of the present invention.

Optionally, in other embodiments, the circuit protection device provided in the second aspect of the present invention may further include a communication unit. Referring to fig. 4, fig. 4 is a schematic diagram illustrating an architecture of a circuit protection device according to some embodiments of the invention.

As shown in fig. 4, in some embodiments of the present invention, the circuit protection device 40 may also be preferably configured with the communication unit 14. The control unit 13 of the circuit protection device 40 may be connected to an external control terminal such as a vehicle system of a vehicle via the communication unit 14, and may acquire a protection policy and a rated current threshold I required for implementing the circuit protection method from the control terminal via the communication unit 14 _normal Short circuit current threshold I _short And the like, so that the online, dynamic and targeted protection of the protected circuit is realized according to the load characteristics, rated working current and/or real-time state of each wire harness, power supply and/or load in the protected circuit.

Referring specifically to fig. 5, fig. 5 illustrates a schematic circuit diagram of a vehicle power supply system according to some embodiments of the present invention. As shown in fig. 5, in a vehicle power supply system 50 provided in some embodiments of the present invention, a generator 51, at least one storage battery 52, a plurality of loads 531 to 533, and at least one circuit protection device 541 to 546 are arranged.

The circuit protection device 541 is disposed in a main circuit of the vehicle power supply system 50 and divides the vehicle power supply system 50 into a plurality of power supply networks isolated from each other, wherein the generator 51 and at least one

first load

532, 533 are disposed in the first power supply network, and the at least one battery 52 and at least one second load 533 are disposed in the second power supply network. The circuit protection device 542 is disposed on a branch where the generator 51 is located, and is configured to provide protection for the generator 51 and the wire harness on the branch. The circuit protection devices 543 to 545 are respectively arranged on the branches where the loads 531 to 533 are located, and are respectively used for protecting the loads 531 to 533 and the wire harnesses on the branches. The circuit protection device 546 is disposed on a branch where the battery 546 is located, and is configured to provide protection for the battery 546 and the wire harness on the branch.

In the process of implementing circuit protection on the vehicle power supply system 50, a vehicle controller (not shown) will respond to the power-on start of the vehicle to acquire the load characteristics, rated operating current and/or real-time status of the protected circuit connected to each of the circuit protection devices 541 to 546 and issue them to each of the circuit protection devices 541 to 546 for implementing the above-mentioned circuit protection method provided by the first aspect of the present invention.

For example, for the circuit protection device 541 provided in the main circuit, the vehicle controller (not shown) may issue protection policy information for simultaneously adopting the short-circuit protection mode, the thermal protection mode, and the high-current protection mode via the CAN, LIN, or other communication lines of the vehicle according to the importance thereof. In addition, the vehicle controller (not shown) may also obtain the maximum operating current I of the generator 51 _max Temperature measurement value T and temperature upper limit value T _max And/or overload time threshold t ₀ And issues it to the communication unit 14 of the circuit protection device 541.

With further reference to FIG. 6, FIG. 6 illustrates a flowchart provided in accordance with some embodiments of the inventionThe flow diagram of the circuit protection method is shown. As shown in fig. 6, in response to data issued by the vehicle system, the circuit protection device 541 may first respond to the maximum operating current I of the generator 51 _max Determining its rated current threshold I _normal (e.g.: I _normal ＝I _max ) Overload current threshold I _large (e.g.: I _large ＝1.2*I _max ) And/or short-circuit current threshold I _short (e.g.: I _short ＝2*I _max ). The circuit protection device 541 can then separate the current measurement I from the rated current threshold I _normal Overload current threshold I _large Short-circuit current threshold I _short A comparison is made to make a current magnitude classification.

Specifically, in response to the current measurement I being less than or equal to the rated current threshold I _normal (i.e. I<I _normal ) The circuit protection device 541 can determine that no failure has occurred in the main circuit of the vehicle power supply system 50. At this point, the circuit protection device 541 may keep its execution units closed to maintain proper operation of the various power supplies and/or loads on the protected circuit.

Responsive to the current measurement I being greater than the rated current threshold I _normal But is smaller than the overload current threshold I _large (i.e. I _normal <I<I _large ) The circuit protection device 541 can determine that there is a slight circuit abnormality in the main circuit of the vehicle power supply system 50. At this time, the circuit protection device 541 may perform an integral operation on the current measurement value I (t) obtained in real time to simulate the heating value Q (t) of each wire harness, power source and/or load in the protected circuit, i.e., Q (t) = ≡i (t) ² Dt and comparing the simulated heating value Q (t) with a pre-configured heating value threshold Q ₀ A comparison is made to determine the timing of cutting off the protected circuit to accurately and reliably prevent damage to the individual harnesses, power sources and/or loads due to excessive heat buildup.

Further, in some embodiments, the circuit protection device 541 is preferably further configured to respond to data issued by a vehicle controller (not shown) by providing a plurality of power sources 51-52, and a plurality of power sources for each of the plurality of power sources 50 of the vehicle power supply system,Impedance and temperature upper limit value T of loads 531 to 533 _max And/or heat dissipation conditions, deducing the element with the lowest heat tolerance in the system (such as the generator 51), and then according to the temperature measurement value T and the upper temperature limit value T of the generator 51 _max On-line calculation of the thermal threshold Q of the thermal protection mode ₀ Thereby providing dynamic thermal protection to the generator 51.

Still further, in some embodiments, the heat threshold Q is determined online as described above ₀ May be implemented by a vehicle controller (not shown) to reduce the data processing load of the circuit protection device 541. In addition, the vehicle controller (not shown) may also determine the heat threshold Q based on online ₀ On-line fitting of thermal protection current threshold I _thermal Curve I of the variation with respect to the duration t _thermal T, and fitting the variation curve I _thermal T to the circuit protection device 541. Thus, the circuit protection device 541 can obtain the change curve I from the vehicle controller (not shown) _thermal -t, and according to the variation curve I _thermal T to implement a delay protection based on the heating value Q, thereby reducing the data processing load thereof.

With continued reference to FIG. 6, in response to the current measurement I being greater than the overload current threshold I _large But is less than the short-circuit current threshold I _short (i.e. I _large <I<I _short ) The circuit protection device 541 can determine that there is a significant circuit abnormality in the main circuit of the vehicle power supply system 50. At this time, the circuit protection device 541 can measure the current I to be larger than the overload current threshold I _large Is counted according to the acquired overload time threshold t ₀ To determine the timing of switching off the protected circuit and thereby provide fast, reliable delay protection of less than 100ms in high current mode.

Responsive to the current measurement I being greater than the short circuit current threshold I _short (i.e. I>I _short ) The circuit protection device 541 can determine that a short-circuit fault has occurred in the main circuit of the vehicle power supply system 50. At this time, the control unit 13 can immediately disconnect its execution unit, cut off the main circuit of the vehicle power supply system 50 to enterAnd row instant short-circuit protection, thereby providing instant short-circuit protection within 5ms in short-circuit mode. By providing immediate short-circuit protection within 5ms, the present invention can greatly reduce the type selection requirements for the main loop wiring harness of the vehicle power supply system 50, thereby facilitating the reduction of the wiring harness cost, size and weight of the vehicle power supply system 50.

Then, in response to the disconnection of the circuit protection device 541, at least one

first load

532, 533 arranged in the first power supply sub-network may be powered by the generator 51 that is operating normally, while at least one second load 533 arranged in the second power supply sub-network may be powered by at least one battery 52 that is operating normally. Thus, by using the circuit protection device 541 to divide the vehicle power supply network into a plurality of relatively independent power supply networks and disposing the independent power supplies 51, 52 in each power supply network, the present invention can isolate each power supply network from each other without affecting each other. Even if any one or more power supply and sub-networks fail, normal power supply and operation of other loads in other power supply and sub-networks are not affected.

For example, the vehicle controller (not shown) may issue the corresponding protection strategy information and the maximum operating current I as described above for the

circuit protection devices

542 and 546 provided in the branches where the power sources such as the generator 51 and the battery 52 are located _max Temperature measurement value T and temperature upper limit value T _max And/or overload time threshold t ₀ . Each of the

circuit protection devices

542 and 546 may provide on-line, dynamic and targeted protection to the corresponding power source and harness according to the acquired data, and the specific embodiments thereof are similar to those of the circuit protection device 541, and will not be described herein.

For example, the vehicle controller (not shown) may acquire load information indicating the characteristics of each load and the maximum operating current I for the circuit protection devices 543 to 545 provided in the branch circuits where each load is located _max Temperature measurement value T and temperature upper limit value T _max And/or overload time threshold t ₀ And is sent to the corresponding circuit protection devices 543 to 545 via the communication lines such as CAN and LIN of the vehicle. In response to data issued by the vehicle system, each of the circuit protection devices 543 to 545The protection strategy to be adopted can be determined according to the obtained load information, and the protection strategy can be used according to the obtained load information and the maximum working current I _max Determining a nominal current threshold I required to implement circuit protection _normal Overload current threshold I _large And/or short-circuit current threshold I _short 。

Specifically, in some embodiments for loads 531 containing inductive elements such as wipers, proportioners, transformers, etc., the load information indicates inductive load characteristics. In response to the load information indicating the inductive load characteristics, the circuit protection device 543 may determine a protection strategy employing a short-circuit protection mode and a thermal protection mode, and based on the load characteristics of the load 531 and the maximum operating current I _max Determining a nominal current threshold I for implementing circuit protection _normal (e.g.: I _normal ＝I _max ) Short-circuit current threshold I _short (e.g.: I _short ＝5*I _max )。

Referring to fig. 7, fig. 7 is a schematic diagram illustrating current waveforms of an inductive load according to some embodiments of the present invention. As shown in fig. 7, the current of inductive load 531 is characterized by a load current that lags the load voltage and can store energy in the inductance. The starting current I (t) of the inductive load 531 at the moment of starting will usually reach the operating current I due to the energy storage requirement of the inductive element ₀ (I ₀ <I _max ) More than 5 times that of (c), but its duration is very short. Thus, by triggering the short-circuit current threshold I of the short-circuit protection mode _short Set to maximum operating current I _max More than 5 times and is configured with a delay protection mode based on the heating value Q, the invention can prevent the false triggering of the instantaneous starting current I (t) to the circuit protection device 543 on one hand and can prevent the inductive load 531 from being at the rated current threshold I on the other hand _normal To short-circuit current threshold I _short In the current interval between them, overheat damage occurs.

Alternatively, in other embodiments directed to light, seat heating, window heating type loads 532, the load information indicates resistive load characteristics. Responsive to load information indicative of resistive load characteristics The protection device 544 can determine the protection strategy using the short-circuit protection mode and the high-current protection mode, and can determine the protection strategy according to the load characteristics of the load 532 and the maximum working current I _max Determining a nominal current threshold I for implementing circuit protection _normal (e.g.: I _normal ＝I _max ) Overload current threshold I _large (e.g.: I _large ＝2*I _max ) And a short-circuit current threshold I _short (e.g.: I _short ＝5*I _max )。

Referring to fig. 8, fig. 8 illustrates a schematic current waveform of a resistive load provided according to some embodiments of the present invention. As shown in fig. 8, the current characteristic relationship of the resistive load 532 conforms to ohm's law i=u/R, and there is no phase difference between the load current and the load voltage. Since the current of the resistive load 532 is relatively stable, no significant current will be generated at the instant of power-on. Therefore, the protection threshold value can be set lower on the protection strategy of the resistive load 532, preferably according to the rated current threshold value I _normal Overload current threshold I of 2-3 times _large To perform high current protection so as to prevent short-circuit faults possibly occurring in the follow-up process.

Based on the above description, the circuit protection devices 541 to 546 provided by the second aspect of the present invention may adjust the protection policy and the protection parameters online and in real time according to the specific protection requirements of the protected circuit, so as to provide online, dynamic and personalized circuit protection for the protected circuit. By configuring the circuit protection device supporting the online setting function, vehicle manufacturers and maintenance operators can greatly reduce the inventory requirements on various different types and parameters of the circuit protection device, thereby greatly reducing the consumable cost and the warehouse cost.

It will be appreciated by those skilled in the art that the above-described scheme of determining the protection strategy and the current threshold by the circuit protection devices 541-546 according to the load information is merely a non-limiting embodiment provided by the present invention, and is intended to clearly illustrate the main concept of the present invention and to provide a specific scheme for public implementation, not to limit the scope of protection of the present invention.

Optionally, in other embodiments, the above-mentioned process of determining the protection policy and/or the current threshold according to the load information may also be implemented by a vehicle controller (not shown), and then the determined protection policy and/or the current threshold may be issued to the corresponding circuit protection devices 541-546 by the vehicle controller (not shown). Thus, the present invention can further reduce the data processing load of the circuit protection devices 541 to 546, so as to reduce the configuration requirements of the circuit protection devices 541 to 546 and provide timeliness of the circuit protection devices 541 to 546.

Further, as shown in fig. 6, in response to any one of the circuit protection devices 541 to 546 being disconnected, it may also broadcast a notification message of the disconnection itself to the CAN, LIN, or other communication lines of the vehicle via the communication unit, and provide a fault notification to the vehicle and the user in time. In addition, the disconnected circuit protection devices 541-546 may also generate corresponding fault reports according to the protection mode in which the shutdown operation is performed, for querying by the vehicle system and/or a technician responsible for repairing the vehicle, and as a data base for vehicle fault diagnosis.

Referring further to fig. 9, fig. 9 is a schematic diagram illustrating an architecture of a circuit protection device according to some embodiments of the present invention.

As shown in fig. 9, in some preferred embodiments, the circuit protection device 90 provided in the second aspect of the present invention may further include a plurality of current detection units 911 to 913 and a plurality of execution units 921 to 923. The plurality of current detection units 911 to 913 and the execution units 921 to 923 are connected to the same control unit 93, so that protection is provided to one or more protected circuits by the control unit 93 in a unified manner. Thus, the integration level of the circuit protection device 90 can be further improved, so that the miniaturization and the light weight of the circuit are facilitated.

While, for purposes of simplicity of explanation, the methodologies are shown and described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts may, in accordance with one or more embodiments, occur in different orders and/or concurrently with other acts from that shown and described herein or not shown and described herein, as would be understood and appreciated by those skilled in the art.

Those of skill in the art would understand that information, signals, and data may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

Although the control unit 13 described in the above embodiment may be implemented by a combination of software and hardware. It is understood that the control unit 13 may also be implemented solely in software or hardware. For a hardware implementation, the control unit 13 may be implemented within one or more Application Specific Integrated Circuits (ASICs), digital Signal Processors (DSPs), programmable Logic Devices (PLDs), field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic devices for performing the functions described above, or a selected combination thereof. For software implementation, the control unit 13 may be implemented by separate software modules, such as program modules (procedures) and function modules (functions), running on a common chip, each of which performs one or more of the functions and operations described herein.

The various illustrative logical modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of protecting a circuit, comprising the steps of:

obtaining a measure of current flowing through the protected circuit;

comparing the current measurement to a rated current threshold and a short circuit current threshold of the protected circuit;

cutting off the protected circuit to perform instant short-circuit protection in response to a comparison result that the current measurement value is greater than the short-circuit current threshold value; and

and determining the time for cutting off the protected circuit according to the current measured value to carry out delay protection according to the comparison result that the current measured value is larger than the rated current threshold value but smaller than the short-circuit current threshold value.

2. The circuit protection method of claim 1 wherein said step of determining the timing of cutting off said protected circuit for delay protection based on said current measurement comprises:

performing an integration operation on the current measurement value to simulate the heating value of the protected circuit; and

and in response to the heating value reaching a configured heating value threshold, cutting off the protected circuit to perform delay protection based on the heating value.

3. The circuit protection method of claim 2 wherein said step of determining the timing of cutting off said protected circuit for delay protection based on said current measurement further comprises:

Acquiring a temperature measurement of the protected circuit; and

and determining the heat threshold according to the temperature measured value and the upper temperature limit value of the protected circuit.

4. The circuit protection method of claim 1 wherein said step of determining the timing of cutting off said protected circuit for delay protection based on said current measurement comprises:

acquiring a change curve of a thermal protection current threshold value relative to duration, wherein the thermal protection current threshold value on the change curve is calculated and determined according to the configured thermal threshold value;

counting the duration of time that the current measurement value is greater than the rated current threshold value;

determining the thermal protection current threshold according to the duration and the change curve; and

and in response to the current measurement being greater than the thermal protection current threshold, cutting off the protected circuit for heating-based delay protection.

5. The circuit protection method of claim 1, 2 or 4 wherein the step of determining the timing of cutting off the protected circuit for delay protection based on the current measurement comprises:

comparing the current measurement to an overload current threshold of the protected circuit, wherein the overload current threshold is greater than the rated current threshold and less than the short circuit current threshold;

In response to a comparison that the current measurement is greater than the overload current threshold, counting a duration that the current measurement is greater than the overload current threshold; and

and responsive to the duration reaching a configured overload time threshold, switching off the protected circuit for delay protection based on a delay time.

6. The circuit protection method of claim 5, wherein prior to the step of performing the delay protection, the circuit protection method further comprises the steps of:

load information of the protected circuit is obtained;

in response to the load information indicating that the protected circuit has an inductive load characteristic, employing the heat generation-based delay protection; and

the delay time based on the delay time is employed in response to the load information indicating that the protected circuit has resistive load characteristics.

7. The circuit protection method of claim 6, wherein prior to the step of performing the delay protection, the circuit protection method further comprises the steps of:

acquiring the rated current threshold of the protected circuit; and

and determining the short-circuit current threshold and/or the overload current threshold of the protected circuit according to the load information and the rated current threshold of the protected circuit.

8. The circuit protection method of claim 1, further comprising the steps of:

in response to the protected circuit being cut off, a fault report is generated according to a protection mode that cuts off the protected circuit.

9. A circuit protection device, comprising a current detection unit, an execution unit, and a control unit, wherein the control unit is connected to the current detection unit and the execution unit and configured to:

acquiring, via the current detection unit, a measured value of current flowing through the protected circuit;

in response to a comparison result that the current measurement value is greater than the short-circuit current threshold value, cutting off the protected circuit through the execution unit so as to conduct instant short-circuit protection; and

and determining the moment for cutting off the protected circuit according to the current measured value to carry out delay protection through the execution unit according to the comparison result that the current measured value is larger than the rated current threshold value but smaller than the short-circuit current threshold value.

10. The circuit protection device of claim 9, further comprising a communication unit, wherein the control unit is connected to a control terminal via the communication unit and is further configured to:

Obtaining, via the communication unit, a protection policy implemented on the protected circuit from the control terminal, wherein the protection policy indicates a short circuit protection mode and at least one delay protection mode; and/or

Obtaining, via the communication unit, one or more of a rated current threshold, a short circuit current threshold, a heat threshold, a temperature upper limit, a thermal protection current threshold change curve with respect to duration, an overload current threshold, and an overload time threshold of the protected circuit from the control terminal; and/or

Acquiring a temperature measurement of the protected circuit from the control terminal via the communication unit; and/or

And sending a prompt message that the protected circuit is cut off and/or a fault report indicating a protection mode of cutting off the protected circuit to the control terminal through the communication unit.

11. A computer readable storage medium having stored thereon computer instructions which, when executed by a processor, implement the circuit protection method according to any of claims 1 to 8.

12. A vehicle power supply system, characterized in that at least one circuit protection device as claimed in claim 9 or 10 is arranged in the vehicle power supply system.