High-voltage electronic fuses and intelligent high-voltage power distribution units for vehicles

Abstract

This invention provides a high-voltage electronic fuse for vehicles, comprising a MOSFET module, a pre-charge circuit, an output voltage acquisition circuit, an isolation drive circuit, and a signal isolation circuit. The MOSFET module, connected at both ends to the high-voltage input and high-voltage output terminals of the high-voltage main circuit, is connected in parallel with the pre-charge circuit. The isolation signal drive circuit includes a high-voltage side and a low-voltage side. The switching signal Pre_EF of the pre-charge circuit input on the low-voltage side and the switching signal ON_EF of the MOSFET module can respectively isolate and drive the high-voltage side signals S1 and S2. The isolation drive circuit uses the high-voltage output terminal HV_OUT as a reference ground signal for the high-voltage side. Furthermore, this invention also discloses an intelligent high-voltage power distribution unit for vehicles. This invention, through optimized design and effective driving of each sub-module of the electronic fuse, can provide safe protection for the high-voltage circuit and its operating equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of power transmission and distribution protection for new energy vehicles, and in particular relates to a high-voltage electronic fuse and an intelligent high-voltage power distribution unit for vehicles. Background Art

[0002] In the vehicle's power distribution device, fuses are often used for circuit protection. The power of the power battery is distributed to various components through the PDU (Power Distribution Unit), such as DCDC, oil pump, air pump, PTC, motor controller, etc.

[0003] In order to reduce carbon emissions, there are more and more new energy vehicles. As the source of energy and power for new energy vehicles, the high-voltage power battery of the new energy vehicle generally has a high-voltage operating range of 250V to 750V. However, the traditional PDU power distribution device adopts the method of relay / contactor + thermal fuse or directly adopts the electronic fuse (eFuse module) generally suitable for low voltage to protect the main distribution circuit, which cannot effectively protect the working state of the main distribution circuit of the high-voltage battery of 250V to 750V. For example, Chinese patent application CN202222464550 discloses a power distribution unit, a vehicle power system and a vehicle. The patent uses multiple parallel efuse modules in a power distribution unit to protect each low-voltage electronic component. Its conventional eFuse module can only be used to protect the low-voltage current circuit after the DC / DC module is converted, or to protect the 12V low-voltage circuit after the battery output, and cannot directly protect the DC / DC module in the high-voltage circuit or the operating equipment such as the permanent magnet synchronous motor. In actual work, when problems occur in the vehicle's high-pressure circuit, they are often more likely to deteriorate and develop into more serious safety accidents in a shorter period of time than low-pressure circuits.

[0004] Therefore, in order to safely protect the high-voltage circuits of new energy vehicles, it is urgent to design a high-voltage electronic fuse and an intelligent high-voltage distribution unit for vehicles. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] The present invention provides a high-voltage electronic fuse and an intelligent high-voltage power distribution unit for a vehicle. By optimizing the design and effectively driving the various submodules of the electronic fuse, a high-voltage circuit and its operating equipment can be safely protected. In addition, a pre-charging circuit with strong heat dissipation is further designed, and the corresponding pre-charging time is set by estimating the value of the load input capacitance, so as to ensure the safe use of the high-voltage electronic fuse.

[0007] (II) Technical solution

[0008] The invention provides a high-voltage electronic fuse for a vehicle, comprising a MOSFET module, a pre-charging circuit, an output voltage acquisition circuit, an isolation drive circuit and a signal isolation circuit, wherein the input and output ends of the MOSFET module are respectively connected to a high-voltage input end HV_IN and a high-voltage output end HV_OUT of a high-voltage main circuit, and the MOSFET module and the pre-charging circuit are connected in parallel, the input and output ends of the output voltage acquisition circuit are respectively connected to the high-voltage output end HV_OUT and the input end of the signal isolation circuit, the isolation signal drive circuit comprises a high-voltage side and a low-voltage side, a switch signal Pre_EF of the pre-charging circuit inputted at the low-voltage side and a switch signal ON_EF of the MOSFET module can respectively isolate and drive signals S1 and S2 on the high-voltage side, the signal S1 is a gate drive voltage of a power switch tube of the MOSFET module, the signal S2 is a gate drive voltage of a power switch tube of the pre-charging circuit, the isolation drive circuit uses the high-voltage output end HV_OUT as a reference ground signal on the high-voltage side, the signal isolation circuit is used to isolate the received detection signal, and output the signal after isolation conversion.

[0009] Preferably, the MOSFET module is specifically a SiC MOSFET module, which includes one or more parallel SiC MOSFET tubes Q1~Qn, the pre-charge routing resistor R3, the resistor R4 and the SiC MOSFET tube Qr are connected in series in sequence, and the resistors R3 and R4 dissipate heat through the aluminum substrate on the back of the PCB.

[0010] Preferably, the isolation drive circuit includes an isolation chip with a driving function, one side of the isolation chip is a low-voltage side, and the other side is a high-voltage side, the low-voltage side includes a switch signal Pre_EF, a switch signal ON_EF, a working power supply voltage VCC_ISO, and a signal interface of the ground terminal GND, and the high-voltage side includes a signal S1, a signal S2, a reference ground signal HV_OUT of the high-voltage output terminal, and a signal interface of the gate-source voltage difference VCC_HV powered by the drive chip.

[0011] Preferably, before the SiC MOSFET module is turned on, the pre-charging circuit is first turned on by a valid switching signal Pre_EF. After the pre-charging circuit works for a period of time or meets certain conditions, the SiC MOSFET module is turned on by a valid switching signal ON_EF and the pre-charging circuit is turned off.

[0012] Preferably, a buffer circuit is further included, wherein the buffer circuit is composed of a capacitor C1, a resistor R1, a resistor R2, and a capacitor C2 connected in series in sequence, and two ends of the buffer circuit are connected to a high-voltage input terminal HV_IN and a high-voltage output terminal HV_OUT.

[0013] Preferably, it also includes a temperature acquisition circuit and a current acquisition circuit. The temperature acquisition circuit is arranged at the heating point of the MOSFET module, and can output the real-time collected temperature value to the input end of the signal isolation circuit. The current acquisition circuit is arranged at the output end of the MOSFET module, and can output the real-time collected current value Current to the input end of the signal isolation circuit.

[0014] Preferably, it further comprises an input voltage acquisition circuit, wherein the input and output terminals of the input voltage acquisition circuit are respectively connected to the high voltage input terminal HV_IN and the input terminal of the signal isolation circuit.

[0015] Preferably, the pre-charging time T of the pre-charging circuit is p Determined as follows:

[0016] According to the following formula, the capacitance C of the load input capacitor is in Make estimates;

[0017]

[0018] Where U t is the voltage value collected in real time by the output voltage collection circuit during pre-charging, U HV_OUT is the output voltage of the high-voltage main circuit when the MOSFET module is normally turned on after the pre-charge is completed, R p is the resistance of the pre-charge circuit, C in is the load input capacitance; T is the voltage value U t The pre-charge timing time, and the initial voltage is 0; according to the load input capacitance C in The size of the pre-charge time T of this or the next time is adjusted adaptively p .

[0019] On the other hand, the present invention also discloses an intelligent high-voltage power distribution unit for a vehicle, wherein the intelligent high-voltage power distribution unit comprises one or more electronic fuses connected in series and / or in parallel with each other, and the electronic fuse is any of the high-voltage electronic fuses for a vehicle described above.

[0020] Preferably, the vehicle is a new energy vehicle, and the voltage operating range of the electronic fuse is 250V to 750V.

[0021] In another aspect, the present invention further discloses a vehicle, comprising the above-mentioned intelligent high-voltage power distribution unit for a vehicle.

[0022] (III) Beneficial effects

[0023] The high-voltage electronic fuse and intelligent high-voltage power distribution unit for vehicles of the present invention have the following advantages:

[0024] 1) First, the present invention adopts a method of forming an electronic fuse (i.e., an eFuse module) based on SiC MOSFET, which has fast response speed and self-diagnosis function, and its intelligence level is higher than that of traditional eFuse and PDU. The isolation drive circuit of the eFuse module adopts an isolation design, and the drive signal of the external controller is electrically isolated from the signal of the drive MOSFET inside the eFuse module, so that the signal interference can be effectively isolated and the problem of driving the high-voltage MOSFET can be solved. The drive power supply inside the eFuse module and the external control power supply are different power supplies, and the power supplies are isolated from each other and do not affect each other; for the switch control of the 250V~750V high-voltage circuit, the eFuse module is also equipped with a pre-charging circuit, which is composed of SiC MOSFET and resistor, which can prevent large current shocks from occurring in the circuit, and the eFuse module adopts a metal shell for modular design, the SiC MOSFET and the resistor of the pre-charging circuit are close to the front of the PCB, and heat dissipation holes are arranged, and an aluminum substrate is designed on the back of the PCB, and the aluminum substrate of the PCB is in contact with the metal shell for heat conduction; in this way, the heat inside the eFuse module can be exported to the shell, which is conducive to heat dissipation.

[0025] 2) Secondly, the S1 and S2 drive signals of the eFuse module drive circuit are obtained by using the output voltage HV_OUT connected to the efuse as the reference ground on the high-voltage side. Its implementation method fully utilizes the characteristics of the isolation drive chip; and the eFuse module has an output voltage and input voltage acquisition circuit inside, which can detect the change in the output voltage and cooperate with the isolation drive circuit to adjust the control voltage value of the S1-S2 signal of the eFuse module in real time.

[0026] 3) In addition, the number of SiC MOSFETs in parallel inside the eFuse module can be freely configured according to the driving current value of the driving object, so that a margin can be left during the design; the eFuse module has a buffer circuit inside to prevent damage to the device caused by sudden voltage changes at the output end when the MOSFET is switched; it also has a temperature detection function, and by obtaining the temperature of the eFuse module, faults can be discovered in time; the eFuse module has a current acquisition circuit inside to collect the current flowing through the eFuse module. By obtaining the current value, it can be multiplied by the output voltage value at the eFuse end, thereby obtaining the output power of the eFuse module in real time.

[0027] 4) In order to further improve the safe use of efuse and avoid voltage mutations in the load input capacitor in the high-voltage circuit, the present invention also uses the real-time output voltage of the efuse output and the preset parameters of the input to estimate the size of the load input capacitor, thereby dynamically adjusting the working time of the pre-charging circuit, so that the efuse module can adaptively adjust the pre-charging time according to the size of the input capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a schematic diagram of the system structure of the intelligent high-voltage power distribution unit for new energy vehicles in the present invention;

[0030] Figure 2 It is a schematic diagram of the system structure of a high-voltage electronic fuse used for a vehicle in the present invention;

[0031] Figure 3 It is a system structure schematic diagram of the isolation drive circuit in the high-voltage electronic fuse of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] See also Figure 1 As shown, each power distribution circuit in the intelligent high-voltage power distribution unit (PDU) for vehicles of the present invention is composed of one or more high-voltage electronic fuses (eFuse modules) freely connected in series and parallel; the intelligent high-voltage power distribution unit needs to select the number of eFuse modules according to the number of distributed power supplies; one eFuse module can be used for one power circuit, or multiple eFuse modules can be used for one circuit in series or in parallel; the specific selection method needs to be adapted according to the working current and working voltage of the circuit, as well as the withstand voltage and maximum driving current of the eFuse module, and the high-voltage electronic fuses can be connected in series or in parallel with each other, so as to meet the requirements of current and voltage parameters in actual work. In addition, the intelligent high-voltage power distribution unit PDU also includes a control and detection module that is connected to the eFuse module in communication, so as to detect and control the eFuse module, and obtain the working state of the eFuse module; thereby obtaining the working state of the corresponding power distribution circuit; the control and detection module collects the input and output voltage, current, and temperature in the eFuse, and can comprehensively analyze the working condition of the circuit and make reasonable judgments and predictions on the working state of the system. 。

[0034] The eFuse driving current capability allows for flexible configuration of resettable power switching devices when the module conduction loss does not exceed the module's maximum heat dissipation power. Therefore, the circuit that requires power distribution can customize the eFuse module or combine modules according to the size of the driving current. At the same time, by monitoring the current, voltage, and temperature of the eFuse module circuit, the working status of the circuit can be determined in real time. This not only improves the intelligence of the system, but also effectively controls the cost of the system.

[0035] In order to solve the circuit protection problem in the high-voltage circuit of new energy vehicles, the structure of the high-voltage electronic fuse used in new energy vehicles in the present invention is as follows: Figure 2 As shown, each high-voltage electronic fuse includes a SiC MOSFET module, a buffer circuit, a pre-charging circuit, a temperature acquisition circuit, a current acquisition circuit, an input voltage acquisition circuit, an output voltage acquisition circuit, an isolation drive circuit and a signal isolation circuit.

[0036] See also Figure 2 As shown in the figure, the connection relationship of each circuit sub-module in the eFuse module is as follows: the input and output ends of the SiC MOSFET module are respectively connected to the high-voltage input end HV_IN and the high-voltage output end HV_OUT of the high-voltage main circuit, and the SiC MOSFET module, the buffer circuit and the pre-charging circuit are connected in parallel, that is, the two ends of the buffer circuit and the pre-charging circuit are also connected to the high-voltage input end HV_IN and the high-voltage output end HV_OUT; the input and output ends of the input voltage acquisition circuit are respectively connected to the high-voltage input end HV_IN and the input end of the signal isolation circuit; the input and output ends of the output voltage acquisition circuit are respectively connected to the high-voltage output end HV_OUT and the input end of the signal isolation circuit; the current acquisition circuit is set in the SiC The output end of the MOSFET module can output the real-time collected current value Current to the input end of the signal isolation circuit; the temperature collection circuit is arranged at the heating part of the SiCMOSFET module, and can output the real-time collected temperature value Temp to the input end of the signal isolation circuit; the isolation signal driving circuit includes a high-voltage side and a low-voltage side, the switch signal Pre_EF of the pre-charging circuit inputted at the low-voltage side and the switch signal ON_EF of the SiCMOSFET module can respectively isolate and drive the signals S1 and S2 of the high-voltage side, the signal S1 is the gate drive voltage of the power switch tubes Q1~Qn of the SiCMOSFET module, the signal S2 is the gate drive voltage of the power switch tube Qr of the pre-charging circuit, and the isolation driving circuit uses the high-voltage output end HV_OUT as a reference ground signal of the high-voltage side; the signal isolation circuit is used to isolate the received detection signal, so as to output the converted and isolated signal to the control and detection module.

[0037] For details, see Figure 2-3As shown, the specific introduction of each sub-circuit module is as follows:

[0038] SiC MOSFET module: The SiC MOSFET module as the main circuit is composed of one or more SiC MOSFETs in parallel, which are connected to the high-voltage input terminal HV_IN and the high-voltage output terminal HV_OUT at both ends of the main circuit, that is, the drain and source of the enhanced NMOS tube are connected to the high-voltage input terminal HV_IN and the high-voltage output terminal HV_OUT respectively. In addition, if the parallel module current or heat control is not considered, the SiC MOSFET module can be a general MOS module.

[0039] In addition, the SiC MOSFET module determines the eFuse module's ability to drive current. For example, the internal resistance of a single MOSFET is 20 milliohms, and the internal resistance of the module is 5 milliohms after four are connected in parallel. Since the driving capability of the eFuse module is limited by the module's heat dissipation capability, if the eFuse module can withstand a conduction loss of 20W, the module's driving current is 63.25A.

[0040] Buffer circuit: The buffer circuit is composed of capacitor C1, resistor R1, resistor R2, and capacitor C2 connected in series in sequence. The series connection of capacitors C1 and C2 increases the withstand voltage of the circuit; the power borne by resistors R1 and R2 in series is half that of a single resistor with the same resistance value.

[0041] Pre-charging circuit: The pre-charging circuit is composed of resistors R3, R4 and power switch tube Qr connected in series in sequence, where Qr is a SiC MOSFET (also an enhanced NMOS tube). Resistors R3 and R4 dissipate heat through the aluminum substrate on the back of the PCB. Because the pre-charging circuit will cause R3 and R4 to heat up severely after detecting a fault, it is necessary to improve the heat dissipation performance of the series resistors; the drive control signal of the pre-charging circuit is Pre_EF, and the Pre_EF input on the low-voltage side is signal S2 after signal isolation by the isolation drive circuit.

[0042] The pre-charging circuit needs to work with the SiC MOSFET module of the main circuit when the efuse is started. That is, before the SiC MOSFET module is officially turned on, the pre-charging circuit is turned on by the effective signal S2 for a period of time or after certain conditions are met, and then the SiC MOSFET module is turned on by the effective signal S1, and the pre-charging circuit is turned off and the signal S2 is invalidated at the same time.

[0043] Temperature acquisition circuit: The temperature acquisition circuit is close to the MOSFET and is used to detect the overall temperature of the eFuse module. The temperature acquisition circuit converts the temperature value of the module into a voltage value, which is converted into a signal EF_Temp after passing through a signal isolation circuit. The temperature signal acquisition circuit can use an analog or digital circuit, and transmits the acquisition signal to the low-voltage side through a signal isolation circuit. The real-time temperature value of the eFuse module is obtained after passing through the signal processing circuit of the control and detection module.

[0044] Current acquisition circuit: The current acquisition circuit can collect the current value flowing through the eFuse module. The acquisition circuit converts the current value Current into the corresponding voltage through the conversion relationship, and converts it into the signal EF_Current after passing through the isolation circuit. There are two implementation methods of the current acquisition circuit, one uses a non-contact Hall sensor and the other uses a resistor acquisition method; both acquisition methods convert the current value into a voltage value; after the obtained voltage signal passes through the signal isolation circuit, signal operation is performed to obtain the actual current value; the signal operation is completed by the MCU (single-chip microcomputer) in the control and detection module.

[0045] Input voltage acquisition circuit / output voltage acquisition circuit: The input and output voltage acquisition circuits are the same. The two circuits detect the high-voltage input end HV_IN and the output end HV_OUT respectively, perform resistor voltage division, and signal isolation, and then convert them into low-voltage side signals EF_VIN and EF_VOUT outputs.

[0046] Isolation drive circuit: see Figure 3 As shown in the figure, the isolation drive circuit is composed of an isolation chip with a driving function. One side of the isolation chip is the low voltage side, and the other side is the high voltage side. Because the driving of SiC MOSFET requires applying the threshold voltage V GS ; The voltage of the S pole is HV_OUT, so the voltage of the G pole drive signals S1 and S2 relative to the output voltage HV_OUT should be greater than or equal to the threshold voltage V GS (The driving signal difference can generally be 12V~20V, which is greater than the threshold voltage V GS 12V); In order to obtain the required drive signals S1 and S2; By directly using HV_OUT as a reference ground on the high-voltage side of the isolation drive circuit, the voltage of S1 and S2 when they are valid can be clamped to (VCC_HV+HV_OUT), where VCC_HV is the gate-source voltage difference of the high-voltage side drive chip power supply, and its value can be 12V~20V, that is, greater than or equal to V GS, VCC_ISO is the working power supply voltage on the low-voltage side, and GND is the ground terminal on the low-voltage side; when the switching signal eFuse_ON (i.e. ON_EF) of the SiC MOSFET module on the low-voltage side is valid, the high-voltage side S1 of the isolation drive circuit is valid, and S1 drives the SiC MOSFET module to turn on; when the switching signal eFuse_PreLoad (i.e. Pre_EF) of the pre-charging circuit on the low-voltage side is valid, the high-voltage side S2 of the isolation drive circuit is valid, and S2 drives the Qr of the pre-charging circuit to turn on; S1 is the gate voltage trigger signal of Q1~Qn of the SiC MOSFET module, S2 is the gate voltage trigger signal of Qr of the pre-charging circuit, and its Ron1 and Ron2 are the driving resistances of the high-voltage side output signal S1-S2.

[0047] It is worth mentioning that the realization Figure 3 The isolation driving circuit shown has many circuit structures and combination circuits with the same output and isolation driving functions. Since their specific circuit structures are not the focus of protection of the present invention, they will not be described here in detail.

[0048] Signal isolation circuit: The signal isolation circuit is composed of an isolation chip, which is responsible for isolating the input voltage Voltage_IN, output voltage Voltage_OUT, temperature Temp, and current Current collected by the input / output detection circuit, and then the control and detection module performs detection signal calculation and S1-S2 control.

[0049] In summary, the present invention realizes the isolation and drive control of the output signal in the eFuse module, and the pre-charging circuit works in conjunction with the main circuit, so that the eFuse module can safely protect the high-voltage circuit and its operating equipment. The input signals ON_EF and Pre_EF are respectively the low-voltage side control signals of the main circuit and the pre-charging circuit in the eFuse module, which are used to generate the corresponding MOS tube drive signals S1 and S2 on the high-voltage side. HV_IN and HV_OUT are the high-voltage input and high-voltage output terminals of the eFuse module connected to the vehicle's high-voltage line. The output signals EF_Temp, EF_Current, EF_VIN and EF_VOUT are respectively the MOS tube temperature, current, voltage input and voltage acquisition signals detected by the eFuse module and output to the low-voltage side.

[0050] It should be pointed out that the efuse module of the present invention realizes high and low voltage electrical isolation design of the input and output signals of the electronic fuse and the external drive and acquisition signals through high and low voltage signal conversion and isolation of the isolation drive circuit and the signal isolation circuit, and the S1 and S2 drive signals of the isolation drive circuit are obtained by using the output voltage HV_OUT as the reference ground of the high voltage side, and its implementation method makes full use of the characteristics of the isolation drive chip.

[0051] In another embodiment, in order to improve the safe use of efuse and avoid voltage mutations in the load input capacitor in the high-voltage circuit, the present invention also uses the real-time output voltage of the efuse output and the preset parameters of the input to estimate the size of the load input capacitor, thereby dynamically adjusting the working time of the pre-charging circuit, so that the control and detection module can adaptively adjust the pre-charging time of the pre-charging circuit in the efuse module according to the estimated size of the load input capacitor.

[0052] Specifically, in high voltage situations, because the voltage on the load input capacitor cannot change suddenly, according to the formula The moment the loop is connected, the capacitor may cause a very large current impact. In order to protect the load in the loop, a pre-charge circuit is required. For the possible large load capacitance problem, the capacitance C of the load input capacitor can be adjusted by the timer in the control and detection module and the pre-charge circuit in the eFuse module. in Make advance estimates;

[0053]

[0054] Where U t is the voltage value collected in real time by the output voltage collection circuit during pre-charging, U HV_OUT is the output voltage value of the high-voltage main circuit when the SiCMOSFET module is normally turned on after the pre-charge is completed, R p is the resistance of the precharge circuit, R p =R3+R4, C in is the load input capacitance; T is the timing time of the timer in the control and detection module, which is consistent with the real-time collected voltage value U t Correspondingly, and assuming that the initial voltage is 0, the input capacitance of the load can be calculated.

[0055] As shown in the above formula, for loads with large input capacitance, the working time of the pre-charge circuit can be appropriately extended; the main circuit can be turned on after the output voltage measurement value of the eFuse module reaches a certain value; for loads with small input capacitance, the working time of the pre-charge circuit can be reduced to accelerate the startup process; since the pre-charge circuit can collect and calculate signals such as the voltage and time of the load input capacitance, the load input capacitance C can be estimated in the control and detection module according to the above formula in The size of the pre-charge time T is adjusted adaptively. p , thus ensuring the safe use of the eFuse module.

[0056] In addition, the present invention estimates the load input capacitance C in Determine the pre-charge time T pThere are many ways to confirm the mapping: it can be a table lookup method (that is, the corresponding C is pre-stored in the control and detection module). in ~T p Numerical correspondence table); it is also possible to establish a relevant mathematical model in the control and detection module to accurately calculate and determine; in addition, considering that there may be a certain error in the estimation of the capacitance value in the above formula, the load input capacitance C in Compared with the preset conventional capacitance value C in the high voltage circuit av After comparison, if the difference between the two is greater than a preset threshold, the pre-charge time Tp is adjusted to increase or decrease accordingly according to a preset mathematical relationship (for example, the two are in a certain direct proportion).

[0057] In a PDU, multiple eFuse modules can be used in a loop in series or in parallel. The series connection of eFuse modules can increase the withstand voltage range of the loop; the parallel connection of eFuse modules can increase the driving current range of the loop. When multiple eFuse modules are connected in series in a loop, the working mode of the module needs to be set. At this time, the input acquisition signal of the first eFuse module with power input is used as the valid signal; the output voltage signal of the last eFuse module is collected as the valid signal; at the same time, the resistance value of the system pre-charge circuit is adjusted to n*R p When multiple eFuse modules are connected in parallel in the loop, the input acquisition signal and output voltage signal acquisition of any module can be used as valid signals; and the current value of the loop should be n*I c ;I c is the current value collected by a single module; the resistance value of the system pre-charge circuit is

[0058] In another aspect, the present invention further claims protection for an intelligent high-voltage power distribution unit for a vehicle, wherein the intelligent high-voltage power distribution unit comprises one or more high-voltage electronic fuses connected in series and / or in parallel.

[0059] Specifically, the vehicle of the present invention is preferably a new energy vehicle, and the high-voltage working range of the high-voltage electronic fuse in its intelligent high-voltage distribution unit is 250V to 750V. The efuse module of the present invention can actually be normally adapted to the high-voltage circuit protection work below 1000V (although the withstand voltage of the MOS tube can reach 1200V, it is generally derated for use in 800V systems). In addition, on special vehicles such as rail transit, the high-voltage range of the SiC MOSFET module in the efuse module can even reach about 1700V.

[0060] Compared with the prior art, the advantages of the present invention are as follows:

[0061] 1. The present invention adopts the eFuse module for power distribution, and can detect the voltage and current values ​​of the power supply passing through the eFuse module; as well as the temperature of the eFuse module; compared with the power transmission method of fuse plus relay / contactor, the solution provided by the present invention has fast response speed and self-diagnosis function, and is suitable for intelligent application occasions.

[0062] 2. The eFuse module is composed of a parallel SiC MOSFET module, a buffer circuit, a pre-charge circuit, a current acquisition circuit, a temperature acquisition circuit, an input voltage detection circuit, an output voltage detection circuit, an isolation drive circuit, and a signal isolation circuit; and the signal that drives the SiC MOSFET is isolated from the external drive signal.

[0063] 3. The circuit for driving SiC MOSFET inside the eFuse module uses HV_OUT as the reference ground, and is implemented with the high-voltage side power supply VCC_HV and the isolation driver chip. Since a positive VGS voltage is required for the MOSFET to turn on, and the D pole of the MOSFET is HV_IN and the S pole is HV_OUT, how to generate S1 and S2 for driving the MOSFET is a problem solved by the present invention.

[0064] 4. By collecting the temperature, input / output voltage, and current values ​​of the eFuse module, the working status of the eFuse module can be accurately obtained, and the change of the dynamic power of the load can be obtained; through the working status of the eFuse module, the working status of the distribution circuit can be obtained.

[0065] 5. Through the modular design of eFuse and the provision of modular integration methods (series / parallel), the series connection improves the circuit's voltage resistance level; the parallel connection improves the circuit's driving current; the combination of these two methods can improve the eFuse module in high voltage or high current applications.

[0066] 6. In high voltage situations, the voltage on the load input capacitor cannot change suddenly. According to the formula The loop will instantly cause a very large current impact; through the timer timing in the control and detection module, and the pre-charge circuit in the eFuse module, the capacitance of the load input capacitor can be estimated; according to the size of the input capacitor, the pre-charge time can be adaptively matched, thereby ensuring the safe use of the eFuse module.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high voltage electronic fuse for a vehicle, It is characterized in that It comprises a MOSFET module, a pre-charging circuit, an output voltage acquisition circuit, an isolation drive circuit and a signal isolation circuit, wherein the input and output ends of the MOSFET module correspond to the high-voltage input end HV_IN and the high-voltage output end HV_OUT of the high-voltage main circuit, respectively, and the MOSFET module and the pre-charging circuit are connected in parallel, the input and output ends of the output voltage acquisition circuit are respectively connected to the high-voltage output end HV_OUT and the input end of the signal isolation circuit, the isolation drive circuit comprises a high-voltage side and a low-voltage side, the switch signal Pre_EF of the pre-charging circuit inputted at the low-voltage side and the switch signal ON_EF of the MOSFET module can respectively isolate and drive the signal S1 and the signal S2 on the high-voltage side, the signal S1 is the gate drive voltage of the power switch tube of the MOSFET module, the signal S2 is the gate drive voltage of the power switch tube of the pre-charging circuit, the isolation drive circuit uses the high-voltage output end HV_OUT as a reference ground signal on the high-voltage side, the signal isolation circuit is used to isolate the received detection signal, and output the signal after isolation conversion; The pre-charging time T of the pre-charging circuit p Determined as follows: According to the following formula, the capacitance C of the load input capacitor is in Make estimates; Where U t is the voltage value collected in real time by the output voltage collection circuit during pre-charging, U HV_OUT is the output voltage of the high-voltage main circuit when the MOSFET module is normally turned on after the pre-charge is completed, R p is the resistance of the pre-charge circuit, C in is the load input capacitance; T is the voltage value U t Pre-charge timing time, and the initial voltage is 0; According to the load input capacitance C in The size of the pre-charge time T of this or the next time is adjusted adaptively p .

2. The high voltage electronic fuse for a vehicle according to claim 1, It is characterized in that The MOSFET module is specifically a SiC MOSFET module, which includes one SiC MOSFET tube or multiple SiC MOSFET tubes connected in parallel. The pre-charge routing resistor R3, the resistor R4 and the SiC MOSFET tube Qr are connected in series in sequence. The resistor R3 and the resistor R4 dissipate heat through the aluminum substrate on the back of the PCB.

3. The high voltage electronic fuse for a vehicle according to claim 2, It is characterized in that The isolation drive circuit includes an isolation chip with a driving function, one side of the isolation chip is a low-voltage side, and the other side is a high-voltage side. The low-voltage side includes a switch signal Pre_EF, a switch signal ON_EF, a working power supply voltage VCC_ISO, and a signal interface of a ground terminal GND. The high-voltage side includes a signal S1, a signal S2, a reference ground signal HV_OUT of a high-voltage output terminal, and a signal interface of a gate-source voltage difference VCC_HV for powering the drive chip.

4. The high voltage electronic fuse for a vehicle according to claim 3, It is characterized in that Before the SiC MOSFET module is turned on, the pre-charging circuit is first turned on by a valid switching signal Pre_EF. After the pre-charging circuit works for a period of time or meets certain conditions, the SiC MOSFET module is turned on by a valid switching signal ON_EF and the pre-charging circuit is turned off.

5. A high voltage electronic fuse for a vehicle according to any one of claims 1 to 4, It is characterized in that It also includes a buffer circuit, which is composed of a capacitor C1, a resistor R1, a resistor R2, and a capacitor C2 connected in series in sequence, and two ends of the buffer circuit are connected to a high-voltage input terminal HV_IN and a high-voltage output terminal HV_OUT.

6. A high voltage electronic fuse for a vehicle according to any one of claims 1 to 4, It is characterized in that It also includes a temperature acquisition circuit and a current acquisition circuit. The temperature acquisition circuit is arranged at the heating part of the MOSFET module, and can output the real-time collected temperature value to the input end of the signal isolation circuit. The current acquisition circuit is arranged at the output end of the MOSFET module, and can output the real-time collected current value Current to the input end of the signal isolation circuit.

7. A high voltage electronic fuse for a vehicle according to any one of claims 1 to 4, It is characterized in that It also includes an input voltage acquisition circuit, the input and output ends of the input voltage acquisition circuit are respectively connected to the high voltage input end HV_IN and the input end of the signal isolation circuit.

8. An intelligent high-voltage power distribution unit for a vehicle, It is characterized in that The intelligent high-voltage power distribution unit includes a plurality of electronic fuses connected in series and / or in parallel, and the electronic fuse is a high-voltage electronic fuse for a vehicle as described in any one of claims 1-7.

9. The intelligent high-voltage power distribution unit for a vehicle according to claim 8, It is characterized in that The voltage operating range of the electronic fuse is 250V to 750V.

10. A vehicle, It is characterized in that The vehicle comprises the intelligent high-voltage power distribution unit for a vehicle according to any one of claims 8-9.

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