Battery disconnection circuit, power management unit, high-voltage power distribution system and control method

Abstract

The invention provides a battery disconnection circuit, a power management unit, a high-voltage power distribution system and a control method. The battery disconnection circuit comprises a main switch branch and a start buffer branch. The first end of the main switch branch is connected with a battery, and the second end of the main switch branch is connected with the first end of the starting buffer branch; the second end of the starting buffer branch is connected with a load; the main switch branch comprises a switch unit and a slow start unit, and the switch unit and the slow start unit are connected in parallel; the switch unit comprises a first power electronic switch and a second power electronic switch which are arranged back to back and is used for bidirectionally conducting the battery disconnection circuit; the slow start unit comprises a third power electronic switch and a slow start load. A non-contact structure is adopted, the risks of arcing and adhesion of mechanical contacts are thoroughly eliminated, the response speed reaches the microsecond level, and the requirement for rapid cutting-off in a high-order safety scene is met.

Description

Technical Field

[0001] This disclosure relates to the field of battery power supply technology, and in particular to a battery disconnection circuit, a power management unit, a high-voltage power distribution system and a control method. Background Technology

[0002] In electric vehicle battery systems, the switching control of the high-voltage circuit currently relies heavily on mechanical relays, specifically applied to the main positive, main negative, pre-charge, and various high-voltage branches (such as DC-DC (Direct Current to Direct Current) / OBC (On-Board Charger) branches, electric drive assembly branches, etc.). A typical power battery pack's high-voltage circuit requires multiple sets of mechanical relays, including main positive relays, pre-charge relays, main negative relays, and relays for each load branch (such as front-drive, rear-drive, and other high-voltage branch load relays). Switching control is achieved through multiple sets of drive signals, and multiple node voltage signals need to be sampled and monitored.

[0003] The above-mentioned control scheme based on mechanical relays has the following technical problems:

[0004] Insufficient response speed and security performance

[0005] Mechanical relays have a fault cut-off time in milliseconds (ms), which cannot meet the microsecond (μs) cut-off requirements of advanced autonomous driving or higher safety levels. Furthermore, mechanical relays are prone to contact arcing, limiting their switching cycle life (typically around 100,000 cycles). They are also susceptible to contact sticking under frequent switching or high-inrush current scenarios, affecting system reliability and increasing maintenance costs.

[0006] Integration and Electromagnetic Compatibility Defects

[0007] Mechanical relays are driven by coils and need to be connected to the Battery Management System (BMS) mainboard via wiring harnesses. Taking a system with 6 relays as an example, at least 18 wiring harnesses are required for effective connection. The arrangement of a large number of wiring harnesses reduces system integration and is not conducive to cost control. At the same time, wiring harnesses are prone to electromagnetic compatibility (EMC) issues, leading to false alarms in drive circuits and diagnostic circuits, affecting the integration of the vehicle's electronic architecture and the safety and reliability of the system.

[0008] Therefore, given the limitations of existing mechanical relays in high-voltage control of electric vehicle power battery systems, there is an urgent need for a technical solution that can improve response speed, reliability, integration, and electromagnetic compatibility. Summary of the Invention

[0009] The technical problem to be solved by this disclosure is to overcome the defects of slow response speed, poor reliability and low integration in the existing battery system, and to provide a battery disconnection circuit, a power management unit, a high-voltage power distribution system and a control method.

[0010] This disclosure solves the above-mentioned technical problems through the following technical solution:

[0011] A battery disconnection circuit is provided, including a main switch branch and a start-up buffer branch;

[0012] The first end of the main switch branch is connected to the battery, and the second end of the main switch branch is connected to the first end of the start-up buffer branch;

[0013] The second end of the start-up buffer branch is connected to the load;

[0014] The main switch branch includes a switch unit and a soft-start unit, wherein the switch unit and the soft-start unit are connected in parallel.

[0015] The switching unit includes two back-to-back first power electronic switches and second power electronic switches for bidirectional conduction of the battery disconnect circuit;

[0016] The soft-start unit includes a third power electronic switch and a soft-start load.

[0017] Preferably, the battery disconnection circuit further includes an output comparison module;

[0018] The input terminal of the output comparison module is connected to the second terminal of the start-up buffer branch, and the output terminal of the output comparison module is connected to the load.

[0019] The output comparison module is used to receive the output voltage of the start-up buffer branch, and switch to the cutoff state when the output voltage is greater than the preset output voltage threshold in the output comparison module.

[0020] Preferably, the main switch branch further includes a first buffer component, a second buffer component, a current sampling component, and a shunt component;

[0021] The first end of the current sampling component is connected to the battery, and the second end of the current sampling component is connected to the main switch branch.

[0022] The first end of the first buffer component is connected to the second end of the current sampling component, and the second end of the first buffer component is connected to the first end of the shunt component.

[0023] The first end of the second buffer component is connected to the second end of the main switch branch, and the second end of the second buffer component is connected to the first end of the shunt component.

[0024] The second end of the current shunt component is connected to the battery.

[0025] Preferably, the main switch branch further includes a redundant switch assembly;

[0026] The first end of the redundant switch assembly is connected to the second end of the second buffer assembly, and the second end of the redundant switch assembly is connected to the second end of the first buffer assembly.

[0027] Preferably, the buffer branch includes at least two sets of buffer units connected in parallel;

[0028] The buffer unit includes a buffer power electronic switch and a buffer assembly connected in series.

[0029] Preferably, the first power electronic switch, the second power electronic switch, and the third power electronic switch are semiconductor thyristors, IGBTs (Insulated Gate Bipolar Transistors), or SiC MOS (Silicon Carbide Metal Oxide Semiconductor Field Effect Transistors).

[0030] In a second aspect, a battery management unit is provided, including the battery disconnect circuit described in the first aspect.

[0031] Thirdly, a high-voltage power distribution system is provided, including the battery management unit described in the second aspect, as well as a main control unit and an isolation voltage regulator unit;

[0032] The isolated voltage regulator unit is connected to the main control unit, the battery management unit, and the power supply respectively, and is used to supply power to the main control unit and the battery management unit.

[0033] Fourthly, a control method for a high-voltage power distribution system is provided, the control method comprising:

[0034] In response to the switching unit being turned on, a test current is applied to the switching unit;

[0035] Obtain the test on-resistance of the switching unit, and calculate the current switching junction temperature corresponding to the switching unit based on the test on-resistance;

[0036] Obtain the current switch junction temperature threshold corresponding to the test current;

[0037] If the current deviation between the current switch junction temperature and the current switch junction temperature threshold is greater than the junction temperature deviation threshold, the output power of the high-voltage power distribution system is limited.

[0038] Preferably, the step of obtaining the current switch junction temperature threshold corresponding to the test current includes:

[0039] Obtain the reference switch junction temperature threshold corresponding to the test current, and the previous test on-resistance;

[0040] The current switch junction temperature threshold is obtained by fitting the reference switch junction temperature threshold and the previous test on-resistance.

[0041] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of this disclosure.

[0042] The positive advancements of this disclosure are as follows: By employing two back-to-back first and second power electronic switches in the main switch branch, their bidirectional blocking capability enables bidirectional conduction and shutdown control of the high-voltage circuit, replacing the traditional combination of main positive and main negative mechanical relays. The contactless structure completely eliminates the risks of arcing and adhesion of mechanical contacts, and the response speed reaches the microsecond level, meeting the rapid disconnection requirements of high-level safety scenarios. In the main switch branch, the switching unit and the soft-start unit are connected in parallel, eliminating the need for additional independent pre-charge relays and complex drive logic, reducing the number of components in the separate pre-charge circuit of traditional solutions, and lowering system complexity and hardware costs. The power electronic switches can be integrated with the drive circuit and sampling circuit through modular design, reducing the number of wiring harnesses and layout space. Attached Figure Description

[0043] Figure 1 A circuit diagram of a battery disconnection circuit provided for an exemplary embodiment of this disclosure;

[0044] Figure 2 A circuit diagram showing a battery disconnection circuit in which the switching unit is an IGBT, provided as an exemplary embodiment of this disclosure;

[0045] Figure 3 A schematic diagram of a comparator circuit provided for an exemplary embodiment of this disclosure;

[0046] Figure 4 A schematic diagram of the structure of a high-voltage power distribution system provided in an exemplary embodiment of this disclosure;

[0047] Figure 5 A flowchart illustrating a control method for a high-voltage power distribution system provided as an exemplary embodiment of this disclosure;

[0048] Figure 6 A graph showing the relationship between normalized on-resistance and junction temperature in a control method for a high-voltage power distribution system provided as an exemplary embodiment of this disclosure.

[0049] Figure 7 A schematic diagram of the control system of a high-voltage power distribution system provided as an exemplary embodiment of this disclosure;

[0050] Figure 8A schematic diagram of an electronic device provided for an exemplary embodiment of this disclosure. Detailed Implementation

[0051] The present disclosure is further illustrated below by way of embodiments, but the present disclosure is not limited to the scope of the embodiments described herein.

[0052] The prefixes such as "first" and "second" used in this disclosure are merely for distinguishing different descriptive objects and do not limit the position, order, priority, quantity, or content of the described objects. The use of ordinal numbers and other prefixes used to distinguish descriptive objects in this disclosure does not constitute a limitation on the described objects. The description of the described objects is given in the claims or the context of the embodiments, and should not be construed as an unnecessary limitation. Furthermore, in the description of this embodiment, unless otherwise stated, "multiple" means two or more.

[0053] Example 1

[0054] Figure 1 A battery disconnect circuit 100 provided for an exemplary embodiment of the present disclosure includes a main switch branch 110 and a start-up buffer branch 120;

[0055] The first end of the main switch branch 110 is connected to the battery 200, and the second end of the main switch branch 110 is connected to the first end of the start-up buffer branch 120.

[0056] The second end of the start-up buffer branch 120 is connected to the load 300;

[0057] The main switch branch 110 includes a switch unit 111 and a soft start unit 112, wherein the switch unit 111 and the soft start unit 112 are connected in parallel.

[0058] The switching unit 111 includes two back-to-back first power electronic switches 1111 and second power electronic switches 1112 for bidirectional conduction of the battery 200 and disconnection of the circuit.

[0059] Specifically, the main switch branch 110 is used for the soft start and bidirectional conduction of the battery disconnection circuit 100. It uses back-to-back series power electronic switches as switch units 111. By utilizing the characteristics of power electronic switches that do not cause contact arcing or sticking, as well as their high reliability, it replaces mechanical relays and eliminates the existing main and negative relay design in the battery disconnection circuit 100, making the design of the entire battery disconnection circuit 100 simpler and reducing application costs.

[0060] The soft-start unit 112 includes a third power electronic switch 1121 and a soft-start load 1122.

[0061] Specifically, the soft-start load 1122 can be a PTC (Positive Temperature Coefficient Thermistor) resistor, with the soft-start unit 112 consisting of the PTC resistor and the third power electronic switch 1121 connected in series. The PTC resistor has low resistance at low temperatures, but its resistance increases sharply with temperature due to heat generated when current flows through it. Alternatively, a buffer resistor, buffer inductor, freewheeling diode, or TVS (Transient Voltage Suppressor Diode) diode can also be used.

[0062] Initially, load 300 is in a zero-voltage state. If the main branch is directly connected, the power supply voltage will be applied to load 300 instantly, resulting in a very large charging or starting inrush current, which can easily damage the power supply, switch or load 300.

[0063] Therefore, when the battery disconnect circuit 100 is initially powered on, the main switch unit 111 disconnects first, and the third power electronic switch in the soft start circuit closes first. At this time, current can only flow through the PTC resistor in the soft start unit 112. The PTC resistor in the soft start branch has a low resistance at room temperature, allowing a certain current to flow (but much less than the inrush current of a direct short circuit), slowly charging the load 300 or providing starting current. At the same time, the current flowing through the PTC resistor generates heat, causing its temperature to rise, and the resistance gradually increases with temperature, further limiting excessive current.

[0064] As current flows through the soft-start unit 112, it continuously supplies power to the load 300 via the start-up buffer branch 120. In one embodiment, the start-up buffer branch 120 includes a capacitive load for buffering. The voltage across the capacitive load gradually increases during the soft-start process. At this time, the equivalent impedance of the load 300 increases, and the loop current naturally decreases. Simultaneously, the PTC resistor, due to continuous heating, has risen to a relatively high resistance value. At this time, the current in the branch where the soft-start unit 112 is located is very small, close to being cut off, and no longer affects the main circuit. When the voltage of the capacitive load approaches the power supply voltage (or the start-up process is completed), the first power electronic switch 1111 and the second power electronic switch 1112 in the main switch unit 111 close. Because the main switch unit 111 has extremely low impedance, it becomes the main current path, and the load 300 enters the normal operating state.

[0065] After the main switch is closed, the third power electronic switch of the soft-start unit 112 is opened, and the soft-start unit 112 stops working. At this time, since no current flows through the PTC resistor, the temperature gradually decreases, and the resistance returns to its initial low resistance value, preparing for the next start.

[0066] The first power electronic switch 1111, the second power electronic switch 1112, and the third power electronic switch 1121 are semiconductor thyristors, IGBTs, or SiC MOS transistors.

[0067] Specifically, thyristors (such as SCRs (Silicon Controlled Rectifiers)) have strong surge protection, low cost, and are suitable for low-frequency applications with high voltage and high current, especially for applications like motor soft starting and reactive power compensation. IGBTs are fully controlled voltage-driven devices that combine the gate control characteristics of MOSFETs with the low conduction loss advantages of bipolar junction transistors (BJTs). They balance high voltage and high current with moderate switching speed, and their conduction loss is lower than that of MOSFETs with the same voltage rating, making them suitable for medium- and high-frequency, high-power applications. SiC MOSFETs are fully controlled voltage-driven devices based on wide-bandgap semiconductor materials (silicon carbide), suitable for high-voltage, high-frequency, and high-temperature environments.

[0068] in, Figure 1 The first power electronic switch 1111 and the second power electronic switch 1112 use SiC MOSFETs. If IGBTs are used, the main switching unit 111 is as follows: Figure 2 As shown.

[0069] In this solution, the main switch branch 110 employs two back-to-back power electronic switches 1111 and 1112, utilizing their bidirectional blocking capability to achieve bidirectional conduction and shutdown control of the high-voltage circuit, replacing the traditional main positive and main negative relay combination of mechanical relays. The contactless structure completely eliminates the risks of arcing and sticking of mechanical contacts, and the response speed reaches the microsecond level, meeting the rapid disconnection requirements in high-level safety scenarios. In the main switch branch 110, the switch unit 111 and the soft-start unit 112 are connected in parallel, eliminating the need for an additional independent pre-charge relay and complex drive logic, reducing the number of components in the separate pre-charge circuit of traditional solutions, and lowering system complexity and hardware costs. The power electronic switches can be integrated with the drive circuit and sampling circuit through modular design, reducing the number of wiring harnesses and layout space.

[0070] As a feasible approach, such as Figure 3 As shown, the battery disconnection circuit 100 also includes an output comparison module 130;

[0071] The input terminal of the output comparison module 130 is connected to the second terminal of the start buffer branch 120, and the output terminal of the output comparison module 130 is connected to the load 300.

[0072] The output comparison module 130 is used to receive the output voltage of the start-up buffer branch 120, and switch to the cutoff state when the output voltage is greater than the preset output voltage threshold in the output comparison module 130.

[0073] In this scheme, the output comparison module 130 includes a differential amplifier 131 and an output comparator 132. A high-voltage sampling circuit is set at the front and rear ends of the main switching unit 111. An operational amplifier is used to build the differential amplifier 130 to amplify the difference voltage between the input and output ends of the main switching power supply.

[0074] If the difference is amplified by 20 times, the voltage difference at this time is 0.1 times the total voltage drop of the first power electronic switch 1111 and the second power electronic switch 1112.

[0075] By setting a comparator latching circuit in the later stage of the main switching power supply, when the current in the first power electronic switch 1111 and the second power electronic switch 1112 is greater than the maximum operating current, the tube voltage drop will be greater than the maximum rated tube voltage drop of 10V (the actual value needs to be adjusted according to different MOS tubes). At this time, the voltage output of the differential amplifier 131 is about 1V.

[0076] After being divided by the voltage divider resistor R5, the difference voltage at the input comparator is greater than the comparison voltage at the inverting input. The output of the open-drain comparator 132 is in a high-impedance state, and the level is pulled up to a high voltage by the pull-up resistor. The OVP (Over Voltage Protection) output is high, forcibly pulling the reference voltage at the inverting input to near 0V. Since the comparator has a DC bias in the non-inverting phase, the comparator is kept in a high-impedance state and latches itself.

[0077] As one possible implementation, the main switch branch 110 further includes a first buffer component 113, a second buffer component 114, a current sampling component 115, and a shunt component 116;

[0078] The first end of the current sampling component 115 is connected to the battery, and the second end of the current sampling component 115 is connected to the main switch branch 110.

[0079] The first end of the first buffer component 113 is connected to the second end of the current sampling component 115, and the second end of the first buffer component 113 is connected to the first end of the shunt component 116.

[0080] The first end of the second buffer component 114 is connected to the second end of the main switch branch 110, and the second end of the second buffer component 114 is connected to the first end of the shunt component 116.

[0081] The second end of the shunt assembly 116 is connected to the battery.

[0082] In this design, the first buffer component 113 and the second buffer component 114 effectively suppress voltage spikes and current surges generated during switching operations. The first buffer component 113 is connected between the current sampling component 115 and the shunt component 116, and can absorb transient energy at the input of the main switch branch 110; the second buffer component 114 is connected between the output of the main switch branch 110 and the shunt component 116, and can buffer load surge interference on the output side. The combination of these two components reduces the risk of breakdown of the power electronic switch due to transient high voltage and high current, while protecting the battery and downstream load from impact, and improving the overall anti-interference capability of the circuit.

[0083] The current sampling component 115 is connected in series between the battery and the main switch branch 110, enabling real-time acquisition of main circuit current information (including charging and discharging current, transient peak current, etc.) to provide accurate current feedback to the battery management system (BMS). Combined with auxiliary sampling by the shunt component 116 (such as a high-precision shunt), redundant monitoring and calibration of the current signal can be achieved, ensuring current measurement accuracy. Precise current data supports the BMS in more accurate SOC estimation, overcurrent protection judgment, and power distribution regulation, improving system operational stability.

[0084] The shunt assembly 116 is connected between the buffer assembly and the battery, forming an independent current shunt path and providing dual-loop protection with the main switch branch 110. When the main switch branch 110 malfunctions (such as a power electronic switch failure), the shunt assembly 116 can work with the buffer assembly to limit the fault current and prevent the fault from spreading. This redundant design significantly reduces the system risk caused by single-point failure, meets the stringent requirements of electric vehicle functional safety standards for high-voltage circuits, and is particularly suitable for the complex operating conditions in advanced intelligent driving.

[0085] On the other hand, the shunt component 116 can dynamically distribute current according to the circuit state. When the main switch branch 110 is lightly loaded or in standby mode, it guides part of the current to flow through a low-loss path, reducing the conduction loss of the main switch branch 110. At the same time, the energy absorption and release characteristics of the buffer component can recover transient energy and feed it back to the battery through the shunt component 116, achieving efficient energy utilization and indirectly improving the system's energy efficiency.

[0086] As one possible implementation, the main switch branch 110 also includes a redundant switch assembly 117;

[0087] The first end of the redundant switch assembly 117 is connected to the second end of the second buffer assembly 114, and the second end of the redundant switch assembly 117 is connected to the second end of the first buffer assembly 113.

[0088] In this scheme, the redundant switch assembly 117 can be a mechanical relay or a power electronic switch. The redundant switch assembly 117 is connected between the second terminal of the second buffer assembly 114 and the second terminal of the first buffer assembly 113, forming a parallel backup path with the main switch branch 110. When the power electronic switch of the main switch branch 110 fails (e.g., conduction failure, shutdown failure), the redundant switch assembly can quickly respond and take over the on / off control, ensuring that the high-voltage circuit can still reliably disconnect or maintain necessary operation under fault conditions, significantly reducing the risk of system paralysis caused by a single point of failure and meeting high-level functional safety requirements. The redundant switch assembly 117, together with the first and second buffer assemblies 114, forms a closed-loop protection network. When the main switch operates or a sudden load change causes a transient energy surge, the redundant switch assembly 117 can work with the buffer assembly to quickly shunt or block abnormal current, avoiding overload failure of a single protection path. For example, when the buffer assembly of the main switch branch 110 is saturated with absorbed energy, the redundant switch can promptly conduct and shunt current, further suppressing voltage spikes and protecting core components from damage.

[0089] As one possible implementation, the start-up buffer branch 120 includes at least two sets of buffer units 121 connected in parallel;

[0090] The buffer unit 121 includes a buffer power electronic switch 1211 and a buffer assembly 1212 connected in series.

[0091] In this scheme, each buffer unit 121 is connected to a different output terminal to a corresponding load, such as a DC fast charging terminal, a front-drive high-voltage terminal, a rear-drive high-voltage terminal, or their high-voltage branches. The buffer components 1212 can be capacitors. The capacitors in each buffer component 1212 provide freewheeling current to the circuit corresponding to the buffer unit 121 when the corresponding buffer power electronic switch 1211 is turned off, thereby absorbing voltage spikes and preventing the buffer power electronic switch 1211 from being damaged due to overvoltage. Simultaneously, the load characteristics at the output terminals differ significantly (e.g., the DC fast charging terminal needs to withstand short-term high-current surges, while the front-drive and rear-drive high-voltage terminals face dynamic power fluctuations), and some loads integrate corresponding buffer capacitors to provide overcurrent and overvoltage protection for the load. Each buffer unit 121 can be independently configured with parameters (such as the impedance value of the buffer component and the response speed of the power electronic switch) according to the load requirements of the corresponding output terminal. For example, a high-capacitance buffer capacitor and a low-on-resistance switch can be configured for the fast charging terminal, and a high-power buffer resistor can be matched for the drive terminal to achieve precise buffering and avoid the drawback of a single buffer parameter being unable to accommodate multiple scenarios. Furthermore, by leveraging the independent control capability of the buffer power electronic switch, the switching of the buffer unit at a specific output terminal can be controlled individually. Different output terminals have different fault modes, and each group of buffer units is only associated with a specific output terminal. When a fault occurs in a branch, the corresponding buffer unit can respond quickly, preventing the fault from being propagated to other branches through the common circuit.

[0092] The battery disconnect circuit 100 provided in this embodiment uses two back-to-back first and second power electronic switches in the main switch branch 110. Utilizing their bidirectional blocking capability, it achieves bidirectional conduction and shutdown control of the high-voltage circuit, replacing the traditional main positive and main negative relay combination of mechanical relays. The contactless structure completely eliminates the risk of arcing and sticking of mechanical contacts, and the response speed reaches the microsecond level, meeting the rapid disconnection requirements in high-level safety scenarios. In the main switch branch 110, the switch unit 111 and the soft-start unit 112 are connected in parallel, eliminating the need for an additional independent pre-charge relay and complex drive logic. This reduces the number of components in the separate pre-charge circuit in traditional solutions, lowering system complexity and hardware costs. The power electronic switches can be integrated with the drive circuit and sampling circuit through modular design, reducing the number of wiring harnesses and layout space.

[0093] Example 2

[0094] This embodiment provides a battery management unit, including the battery disconnect circuit 100 described in Embodiment 1.

[0095] In this solution, the BMS can collect current and voltage signals from each output terminal (fast charging, front drive, rear drive, etc.) and combine this with the status of the corresponding buffer units to achieve differentiated energy distribution. Layered protection can be achieved by utilizing the independent protection and isolation functions of the buffer units in the current disconnect circuit. Simultaneously, the main switch branch 110 is linked to limit the total current, preventing fault propagation. Compared to the single-circuit protection of traditional BMS, this layered response mechanism reduces fault handling time to the microsecond level, meeting the safety requirements of advanced intelligent driving.

[0096] Example 3

[0097] like Figure 4 As shown, this embodiment provides a high-voltage power distribution system 400, including the battery management unit 410 described in the second aspect, as well as a main control unit 420 and an isolation voltage stabilizing unit 430;

[0098] The isolation voltage regulator unit 430 is connected to the main control unit 420, the battery management unit 410 and the power supply respectively, and is used to supply power to the main control unit and the battery management unit.

[0099] In traditional solutions, external battery management unit (BMU) control units require additional wiring harnesses (such as power, signal, and communication harnesses) and independent mechanical fixing structures (such as housings and brackets). In this solution, the BMU 410 is integrated within the high-voltage power distribution system 400, eliminating the need for redundant wiring harnesses and independent structural components, directly reducing material costs. Simultaneously, the integrated design shortens the physical distance between the BMU 410 and high-voltage devices (such as main switch branches and buffer units), reducing signal transmission path loss and indirectly lowering the requirements for wiring specifications, further reducing hardware expenditure. The integrated design of the BMU 410 and the high-voltage power distribution unit avoids the independent installation space required for an external BMU 410. Furthermore, the integrated BMU 410 directly interacts with the main control unit 420 via a short-distance internal communication link, replacing the long-distance wiring harness transmission required in traditional external solutions. The shortened communication path reduces the chance of electromagnetic interference coupling, lowers signal attenuation and bit error rate, and improves data transmission rate.

[0100] Example 4

[0101] This embodiment provides a control method for a high-voltage power distribution system, such as... Figure 5 As shown, the control method includes:

[0102] S101. In response to the switching unit 111 being turned on, a test current is applied to the switching unit 111.

[0103] S102. Obtain the test on-resistance of the switching unit 111, and calculate the current switching junction temperature corresponding to the switching unit 111 based on the test on-resistance;

[0104] S103. Obtain the current switch junction temperature threshold corresponding to the test current;

[0105] S104. In response to the current deviation between the current switch junction temperature and the current switch junction temperature threshold being greater than the junction temperature deviation threshold, the output power of the high-voltage power distribution system is limited.

[0106] In this scheme, an isolated sampling chip is introduced into the high-voltage power distribution system, and a Zener diode is used to output a power supply to the secondary side. When the MOSFETs, which serve as the first power electronic switch and the second power electronic switch, are turned on, the voltage drop across a single MOSFET can be measured. The sampling chip is a duty cycle output sampling chip, which does not occupy the MCU's AD sampling channel, saving resources, and the duty cycle output is not easily affected by interference, resulting in good stability.

[0107] After each turn-on state, a certain delay, such as 50µs, is performed to ensure a relatively stable on-state voltage drop. The MCU records the sampled signal. Each power-on operation requests a 10A load current for switch status detection. After each repeated power-on, the on-resistance, junction temperature, and / or corresponding trend changes are compared to previous values ​​to obtain a reliable lifetime prediction result. When the on-resistance (RdsON) changes abnormally, the solid-state relay can be shut down promptly and an alarm message can be uploaded, effectively preventing MOSFET failure due to accelerated lifespan degradation.

[0108] As one possible approach, step S103 includes:

[0109] Obtain the reference switch junction temperature threshold corresponding to the test current, and the previous test on-resistance;

[0110] The current switch junction temperature threshold is obtained by fitting the reference switch junction temperature threshold and the previous test on-resistance.

[0111] In this scheme, based on the Rdson curve of the SiC MOS transistor following the junction temperature change, the junction temperature of the SiC MOS transistor can be obtained through Rdson. By combining the real-time current acquisition unit and the voltage acquisition unit, the real-time junction temperatures of the SiCMOS transistor corresponding to the first power electronic switch and the SiC MOS transistor corresponding to the second power electronic switch, which are set up back-to-back, can be calculated.

[0112] In one embodiment, the expected junction temperature of the first and second power electronic switches at different water temperatures can also be obtained by combining the temperature of the water channels used to cool the first and second power electronic switches with the data from thermal resistance tests, corresponding to the rated current.

[0113] Under normal operating conditions, the on-state current and voltage drop data are monitored in real time to detect the actual junction temperature. When the temperature exceeds the set value by 10%, it is reported to the vehicle's VCU. The vehicle then begins to reduce the output torque and speed of the rear-wheel drive, lowering the maximum vehicle speed to below 120 km / h. The power of the vehicle's water pump compressor (thermal management unit) is increased, and the water pump flow rate is increased. At this time, the comparator's reference voltage changes in real time according to different water temperature levels (the MCU outputs different reference voltages by changing the duty cycle). After the vehicle reduces power output and increases heat dissipation capacity, the junction temperature decreases. When it falls below the set value by 5%, the alarm disappears, and the BDU continues to operate normally. If the above operations are ineffective, power does not decrease, and junction temperature continues to rise (not exceeding 20%), a second-stage response will be employed. The standard external capacitor for the vehicle is 500uF, and the estimated parasitic inductance at the rear is 8mH. At this point, the relay enters PWM control for power limiting output. Specifically, this is achieved by switching at a 1K switching frequency with a 50% duty cycle, and then gradually increasing the duty cycle based on the junction temperature drop trend. This fully utilizes the power limiting advantage of SiC devices as high-frequency switching electronic components. Simultaneously with the main relay PWM control, continuous communication with the VCU is maintained to determine which circuit is overloaded. The corresponding auxiliary circuit's negative circuit switch is disconnected, protecting the battery and BDU while ensuring that the front / rear drive does not lose power, thus maintaining a certain level of vehicle power.

[0114] If the junction temperature does not decrease under any of the above conditions, and the junction temperature exceeds the set value by 20%, the comparator will trigger the overcurrent hardware latch. At this time, the SiC MOSFET will be forcibly turned off to protect the relay.

[0115] Under extreme short-circuit conditions, it will trigger dual redundant protection of Desat (Desaturation) protection and overcurrent monitoring, effectively preventing the risk of cell spontaneous combustion.

[0116] like Figure 6 As shown in the coordinate graph, the Y-axis represents the normalized reference on-resistance R. DS(on) X-axis reference junction temperature T j The Vgs (gate-source voltage) of the transistor corresponding to the curve in the figure is constant at 18V. At the initial power-on of both the first and second power electronic switches, a 1A power supply test (rear-drive startup) is requested from the VCU, and the on-resistance at this time is measured. Figure 6 The reference on-resistance corresponding to the curve is compared, and then the maximum current curve is refitted to update the protection threshold. After a certain number of uses and time accumulation, the working on-resistance will gradually increase. Each time it increases, the curve is updated in time to fit a new current curve, so that the detailed protection relay will not be overloaded, effectively ensuring driving safety.

[0117] When the offset exceeds 10%, it indicates that the SIC's lifespan has reached a point where it is no longer sufficient for use. At this point, the issue is reported to the VCU, which limits the vehicle's power and requests the user to report the problem and replace the SIC.

[0118] Example 5

[0119] Corresponding to the aforementioned control method embodiments for high-voltage power distribution systems, this disclosure also provides embodiments of a control system 500 for high-voltage power distribution systems.

[0120] Figure 7 A schematic diagram of a control system 500 for a high-voltage power distribution system provided as an exemplary embodiment of the present disclosure. The system includes: a test start-up module 501, a junction temperature calculation module 502, a threshold acquisition module 503, and a power limiting module 504.

[0121] The test start module 504 is used to apply a test current to the switch unit 111 in response to the switch unit 111 being turned on.

[0122] Junction temperature calculation module 502 is used to obtain the test on-resistance of the switching unit 111 and calculate the current switching junction temperature corresponding to the switching unit 111 based on the test on-resistance.

[0123] Threshold acquisition module 503 is used to acquire the current switch junction temperature threshold corresponding to the test current;

[0124] The power limiting module 504 is used to limit the output power of the high-voltage power distribution system in response to the current deviation between the current switch junction temperature and the switch junction temperature threshold being greater than the junction temperature deviation threshold.

[0125] For the system embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this disclosure according to actual needs.

[0126] Example 6

[0127] Figure 8 This is a schematic diagram of the structure of an electronic device according to an example embodiment of the present disclosure. The electronic device includes a memory, a processor, and a computer program stored in the memory and used to run on the processor. When the processor executes the computer program, it implements the control method of the high-voltage power distribution system described in any of the above embodiments. Figure 8The electronic device 90 shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments disclosed herein.

[0128] like Figure 8 As shown, the electronic device 90 can be manifested as a general-purpose computing device, such as a server device. The components of the electronic device 90 may include, but are not limited to: at least one processor 91, at least one memory 92, and a bus 93 connecting different system components (including memory 92 and processor 91).

[0129] Bus 93 includes a data bus, an address bus, and a control bus.

[0130] The memory 92 may include volatile memory, such as random access memory (RAM) 921 and / or cache memory 922, and may further include read-only memory (ROM) 923.

[0131] The memory 92 may also include a program tool 925 (or utility) having a set (at least one) program module 924, including but not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of these examples may include an implementation of a network environment.

[0132] The processor 91 executes various functional applications and data processing by running computer programs stored in the memory 92, such as the control method for a high-voltage power distribution system provided in any of the above embodiments.

[0133] Electronic device 90 can also communicate with one or more external devices 94 (e.g., keyboard, pointing device, etc.). This communication can be performed through input / output (I / O) interface 95. Furthermore, electronic device 90 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public network, such as the Internet) via network adapter 96. As shown, network adapter 96 communicates with other modules of electronic device 90 via bus 93. It should be understood that, although not shown in the figure, other hardware and / or software modules can be used in conjunction with electronic device 90, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID (disk array) systems, tape drives, and data backup storage systems.

[0134] It should be noted that although several units / modules or sub-units / modules of the electronic device have been mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more units / modules described above can be embodied in one unit / module. Conversely, the features and functions of one unit / module described above can be further divided and embodied by multiple units / modules.

[0135] Example 7

[0136] This disclosure also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the control method for the high-voltage power distribution system provided in any of the above embodiments.

[0137] The readable storage medium may be more specifically adopted, including but not limited to: portable disk, hard disk, random access memory, read-only memory, erasable programmable read-only memory, optical storage device, magnetic storage device, or any suitable combination thereof.

[0138] Example 8

[0139] This disclosure also provides a computer program product, including a computer program that, when executed by a processor, implements the control method for the high-voltage power distribution system described in any of the above embodiments.

[0140] The program code for executing the computer program product of this disclosure can be written in any combination of one or more programming languages, and the program code can be executed entirely on a user device, partially on a user device, as a stand-alone software package, partially on a user device and partially on a remote device, or entirely on a remote device.

[0141] While specific embodiments of this disclosure have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this disclosure is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this disclosure, but all such changes and modifications fall within the scope of protection of this disclosure.

Claims

1. A battery disconnect circuit, comprising: The main switch branch and the starting buffer branch are connected in parallel. The first end of the main switch branch is connected with the battery, and the second end of the main switch branch is connected with the first end of the starting buffer branch. The second end of the starting buffer branch is connected with the load. The main switch branch comprises a switch unit and a slow start unit, and the switch unit is connected with the slow start unit in parallel. The switch unit comprises two first power electronic switches and second power electronic switches arranged back to back, and is used for bidirectional conduction of the battery disconnect circuit. The slow start unit comprises a third power electronic switch and a slow start load.

2. The battery disconnect circuit of claim 1, wherein, The battery disconnect circuit further comprises an output comparison module. The input end of the output comparison module is connected with the second end of the starting buffer branch, and the output end of the output comparison module is connected with the load. The output comparison module is used for receiving an output voltage of the starting buffer branch, and switching to an off state when the output voltage is greater than a preset output voltage threshold in the output comparison module.

3. The battery disconnect circuit of claim 2, wherein, The main switch branch further comprises a first buffer assembly, a second buffer assembly, a current sampling assembly and a shunt assembly. The first end of the current sampling assembly is connected with the battery, and the second end of the current sampling assembly is connected with the main switch branch. The first end of the first buffer assembly is connected with the second end of the current sampling assembly, and the second end of the first buffer assembly is connected with the first end of the shunt assembly. The first end of the second buffer assembly is connected with the second end of the main switch branch, and the second end of the second buffer assembly is connected with the first end of the shunt assembly. The second end of the shunt assembly is connected with the battery.

4. The battery disconnect circuit of claim 3, wherein, The main switch branch further comprises a redundant switch assembly. The first end of the redundant switch assembly is connected with the second end of the second buffer assembly, and the second end of the redundant switch assembly is connected with the second end of the first buffer assembly.

5. The battery disconnect circuit of claim 1, wherein, The starting buffer branch comprises at least two groups of buffer units connected in parallel. The buffer unit comprises a buffer power electronic switch and a buffer assembly connected in series.

6. The battery disconnect circuit of any one of claims 1 to 5, wherein, The first power electronic switch, the second power electronic switch and the third power electronic switch are semiconductor thyristors, IGBTs or SiC MOS tubes.

7. A battery management unit, characterized by The battery disconnect circuit comprises the battery disconnect circuit according to any one of claims 1 to 6.

8. A high voltage power distribution system, characterized by The battery management unit comprises the battery management unit according to claim 7, a master control unit and an isolation voltage stabilizing unit. The isolation voltage stabilizing unit is connected with the master control unit, the battery management unit and the power supply respectively, and is used for supplying power to the master control unit and the battery management unit.

9. A control method of a high-voltage power distribution system, characterized by, The control method comprises: In response to the switch unit being turned on, a test current is applied to the switch unit; A test on-resistance of the switch unit is obtained, and a current switch junction temperature corresponding to the switch unit is calculated based on the test on-resistance; A current switch junction temperature threshold corresponding to the test current is obtained; In response to a current deviation value between the current switch junction temperature and the switch junction temperature threshold being greater than a junction temperature deviation threshold, the output power of the high-voltage power distribution system is limited.

10. The control method of a high-voltage power distribution system according to claim 9, characterized by, The step of obtaining the current switch junction temperature threshold corresponding to the test current comprises: acquire a reference switch junction temperature threshold corresponding to the test current and a last test on-resistance; fit the current switch junction temperature threshold based on the reference switch junction temperature threshold and the last test on-resistance.

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