Engine load throwing high-voltage surge suppression circuit

Abstract

The invention relates to an engine load throwing high-voltage surge suppression circuit. The engine load throwing high-voltage surge suppression circuit comprises a detection module, a control module and a discharge module. The detection module responds to a first detection voltage and transmits the first detection voltage to the input end of the control module, and the first detection voltage is a voltage greater than a preset threshold voltage; the input end of the control module responds to the first detection voltage, and the output end of the control module outputs a first signal; the first input end of the discharge module responds to the first signal and is conducted, so that the second end of the discharge module is connected with the positive electrode of the battery, the third end of the discharge module is connected with the negative electrode of the battery, a parallel loop of the discharge module and the battery is formed, the discharge module serves as a load of an external circuit for discharging of the external circuit, the load throwing condition can be eliminated, and the service life of the battery is prolonged. The breakdown of circuit components caused by high-voltage surge generated by sudden current change of an external circuit of the engine is effectively inhibited, and a battery management system is protected.

Description

Technical Field

[0001] The present application relates to the field of automotive electronics, and particularly to a high-voltage surge suppression circuit for engine load shedding. Background Art

[0002] With the widespread application of new energy vehicles and hybrid vehicles, the engine, as an auxiliary power source or power generation unit, often supplies power to the battery pack through a generator. However, during vehicle operation, the engine may suddenly shed its load (i.e., "load shedding"), and at this time, the energy originally supplied to the load cannot be consumed in time, which is extremely likely to cause transient high-voltage surges in the circuit, resulting in too fast a voltage rise rate, and then impacting the battery pack and the control circuit, posing a great potential safety hazard.

[0003] Existing load shedding protection schemes mostly rely on quickly disconnecting the main charging circuit path and attempt to prevent abnormal voltage increase by cutting off the energy input. However, this method has two obvious problems: one is that the disconnection action often lags behind the voltage rise and it is difficult to suppress the surge in time; the other is the lack of an effective energy consumption path, and the high-voltage energy has nowhere to be released, easily leading to risks such as MOS tube breakdown, controller reset, and even vehicle power-off.

[0004] In addition, although some battery management systems (BMS) have overvoltage detection functions, they are usually only used for abnormal alarm or simple disconnection, lacking a sequential control mechanism and an energy discharge path, and cannot meet the requirements for system response speed and safety in the engine load shedding scenario.

[0005] Therefore, there is an urgent need for a load shedding protection circuit that can guide the excess energy to be safely discharged when the engine generates high voltage due to current mutation, effectively suppress the high-voltage surge, and thus achieve effective protection for the battery pack and the entire power supply system. Summary of the Invention

[0006] The present application provides a high-voltage surge suppression circuit for engine load shedding to solve the problem in the prior art that when the engine generates high voltage due to current mutation and breaks down circuit components, the high-voltage surge cannot be effectively suppressed.

[0007] In a first aspect, the present application provides a high-voltage surge suppression circuit for engine load shedding, and the high-voltage surge suppression circuit for engine load shedding includes a detection module, a control module, and a discharge module; The input end of the detection module is connected to the negative pole of the battery, and the output end is connected to the input end of the control module; The first output end of the control module is connected to the first input end of the discharge module; The output end of the discharge module is connected to the external circuit of the engine; In response to the first detection voltage, the detection module transmits the first detection voltage to the input end of the control module, where the first detection voltage is a voltage greater than a preset threshold voltage. In response to the first detection voltage, the input end of the control module outputs a first signal from the output end of the control module. The first input end of the discharge module is turned on in response to the first signal, connecting the second end of the discharge module to the positive electrode of the battery and the third end of the discharge module to the negative electrode of the battery, forming a parallel circuit of the discharge module and the battery, so that the discharge module serves as a load of the external circuit for the external circuit to discharge.

[0008] Optionally, the detection module includes a sampling resistor and an AFE acquisition chip. The input end of the sampling resistor is connected to the negative electrode of the battery, and the output end is connected to the input end of the AFE acquisition chip. The input end of the sampling resistor responds to the detection current of the negative electrode of the battery, converts the detection current into a detection voltage, and the output end of the sampling resistor transmits the detection voltage to the input end of the detection module. When the detection voltage is greater than or equal to the preset threshold voltage, the detection voltage is the first detection voltage, and the input end of the AFE acquisition chip responds to the first detection voltage and transmits the first detection voltage to the input end of the control module.

[0009] Optionally, the control module includes an MCU control chip, the discharge module includes a discharge signal unit, a discharge switch unit, and a discharge resistor, and the discharge switch unit includes a first end of the discharge switch unit, a control end of the discharge switch unit, and a second end of the discharge switch unit. The input end of the discharge signal unit is connected to the first output end of the control module, and the output end is connected to the negative electrode of the battery. The first end of the discharge switch unit is connected to the first end of the discharge resistor, the control end of the discharge switch unit is connected to the positive electrode of the battery, and the second end of the discharge switch unit is connected to the output end of the discharge signal unit. The second end of the discharge resistor is connected to the first end of the discharge switch unit. The control end of the discharge switch unit responds to the voltage of the positive electrode of the battery and turns on the discharge switch unit, so that the first end of the discharge resistor is connected to the positive electrode of the battery, the second end of the discharge resistor is connected to the negative electrode of the battery, and the discharge resistor is in parallel with the battery.

[0010] Optionally, the discharge signal unit includes a first resistor and an optocoupler. The input end of the first resistor is connected to the first output end of the control module, and the output end is connected to the input end of the optocoupler; The output end of the optocoupler is connected to the negative electrode of the battery and the second end of the discharge switch unit; The control end of the discharge switch unit conducts when the voltage of the positive electrode of the battery is at a high level. The first end of the discharge switch unit conducts with the second end of the discharge switch unit, so that the first end of the discharge resistor is connected to the positive electrode of the battery, the second end of the discharge resistor is connected to the negative electrode of the battery, and the discharge resistor is connected in parallel with the battery.

[0011] Optionally, the discharge module further includes a second resistor, a first NPN transistor, a third resistor, a first PNP transistor, a first crystal diode, a second crystal diode, and a fourth resistor.

[0012] Optionally, the input end of the second resistor is connected to the positive electrode of the battery, and the output end is connected to the collector of the first NPN transistor; The emitter of the first NPN transistor is connected to the input end of the third resistor; The output end of the third resistor is connected to the emitter of the first PNP transistor; The collector of the first PNP transistor is connected to the positive electrode of the first crystal diode; The negative electrode of the first crystal diode is connected to the positive electrode of the second crystal diode; The negative electrode of the second crystal diode is connected to the input end of the fourth resistor; The output end of the fourth resistor is connected to the control end of the discharge switch unit.

[0013] Optionally, the control module further includes a charging switch unit. When the discharge switch unit conducts and the discharge resistor is connected in parallel with the battery, the second output end of the MCU control chip outputs a second signal and transmits the second signal to the charging switch unit; The charging switch unit turns off in response to the second signal, so that the external circuit is disconnected from the battery.

[0014] Optionally, the charging switch unit includes a first end of the charging switch unit, a control end of the charging switch unit, and a second end of the charging switch unit; The first end of the charging switch unit is connected to the external circuit, the second end of the charging switch unit is connected to the negative electrode of the battery, and the control end of the charging switch unit is connected to the second output end of the MCU control chip; The control terminal of the charging switch unit responds to the second signal, disconnects the connection between the first end and the second end of the charging switch unit, so as to disconnect the negative pole of the external circuit from the negative pole of the battery, and stops the external circuit from charging the battery.

[0015] Optionally, the control module further includes a fifth resistor, a second NPN-type triode, a sixth resistor, a second PNP-type triode, a third crystal diode, a fourth crystal diode, and a seventh resistor.

[0016] Optionally, the input end of the fifth resistor is connected to the second output end of the MCU control chip, and the output end is connected to the base of the second NPN-type triode; The collector of the second NPN-type triode is connected to the input end of the sixth resistor; The output end of the sixth resistor is connected to the base of the second PNP-type triode; The collector of the second PNP-type triode is connected to the positive pole of the third crystal diode; The negative pole of the third crystal diode is connected to the positive pole of the fourth crystal diode; The negative pole of the fourth crystal diode is connected to the input end of the seventh resistor; The output end of the seventh resistor is connected to the control terminal of the charging switch unit.

[0017] This application relates to an engine load-dump high-voltage surge suppression circuit. The load-dump protection circuit includes a detection module, a control module, and a discharge module. The detection module responds to a first detection voltage and transmits the first detection voltage to the input end of the control module. The first detection voltage is a voltage greater than a preset threshold voltage. The input end of the control module responds to the first detection voltage, and the output end of the control module outputs a first signal. The first input end of the discharge module responds to the first signal and conducts, so that the second end of the discharge module is connected to the positive pole of the battery, and the third end of the discharge module is connected to the negative pole of the battery, forming a parallel circuit of the discharge module and the battery, so that the discharge module serves as a load of the external circuit for the external circuit to discharge, which is beneficial to eliminating the load-dump condition and effectively suppressing the high-voltage surge generated by the current mutation in the engine external circuit from breaking down the circuit components and protecting the battery management system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present invention, and are used together with the specification to explain the principles of the present invention.

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] One or more embodiments are illustrated by way of example in the accompanying drawings corresponding thereto. These exemplary illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, unless otherwise stated, and the drawings in the figures do not constitute a scale limitation.

[0021] Figure 1 It is a schematic structural diagram of the engine load rejection high-voltage surge suppression circuit provided by the present application; Figure 2 It is a schematic circuit diagram of the engine load rejection high-voltage surge suppression circuit provided by the present application. Detailed implementation manners

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0023] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0024] To solve the problems in the prior art, the present application provides an engine load rejection high-voltage surge suppression circuit. Figure 1 It is a schematic structural diagram of the engine load rejection high-voltage surge suppression circuit provided by the present application. The engine load rejection high-voltage surge suppression circuit includes a detection module, a control module, and a discharge module; The input end of the detection module is connected to the negative pole of the battery, and the output end is connected to the input end of the control module; The first output end of the control module is connected to the first input end of the discharge module; The output end of the discharge module is connected to the external circuit of the engine; In response to the first detection voltage, the detection module transmits the first detection voltage to the input end of the control module, where the first detection voltage is a voltage greater than a preset threshold voltage. In response to the first detection voltage at the input end of the control module, the output end of the control module outputs a first signal. In response to the first signal, the first input end of the discharge module conducts, connecting the second end of the discharge module to the positive electrode of the battery and the third end of the discharge module to the negative electrode of the battery, forming a parallel circuit of the discharge module and the battery, so that the discharge module serves as a load of the external circuit for the external circuit to discharge.

[0025] Among them, the input end of the detection module is connected to the negative electrode of the battery, and the output end is connected to the input end of the control module; the first output end of the control module is connected to the first input end of the discharge module; the output end of the discharge module is connected to the external circuit of the engine.

[0026] In the embodiment of the present application, under the normal working state of the system, the detection module continuously monitors the key voltage parameters of the battery system. When the detection module detects that one or more groups of cell voltages reach or exceed the preset threshold voltage (i.e., the first detection voltage), the first detection voltage is output as a voltage signal to the input end of the control module. The first detection voltage is a voltage value higher than the system-set safety range, and usually corresponds to the high-voltage surge generated when the engine suddenly disconnects the load.

[0027] After receiving the first detection voltage, the control module determines that the current system is in a load shedding risk state, and its output end immediately outputs a first control signal to the discharge module to instruct it to perform a protection action.

[0028] After the first input end of the discharge module responds to the first control signal, it enters the conducting state, thus establishing a new energy discharge path. Specifically, the second end of the discharge module is connected to the positive electrode of the battery, and the third end is connected to the negative electrode of the battery, forming a current loop in parallel with the battery by the discharge module. This loop consumes the remaining energy in the external circuit that cannot be consumed due to the engine disconnecting the load through the discharge module, thereby effectively absorbing and suppressing the impact of the high-voltage surge on the battery pack and other electronic devices.

[0029] In a preferred embodiment, the detection module can be composed of an analog front-end chip, an operational amplifier comparator, or a voltage divider in cooperation with an ADC module. The control module can be a microcontroller (MCU) or a digital logic controller with a voltage comparison function. The discharge module can include a power resistor and a power MOS transistor connected in series, and the gate of the MOS transistor is controlled by the control module.

[0030] When the discharge circuit is turned on, the power device inside the discharge module converts the high-voltage current into heat energy and releases it, achieving the purpose of efficiently suppressing the surge voltage and reducing the impact on the battery. This solution ensures that the entire circuit responds promptly and operates reliably through the sequential logic of detection first, control second, and discharge last, and is applicable to various vehicle power systems with engine power sources, especially suitable for protecting the load-dump conditions of new energy vehicles, hybrid systems, or high-power power generation equipment.

[0031] Further, the detection module includes a sampling resistor, and the detection module includes an AFE acquisition chip; The input end of the sampling resistor is connected to the negative electrode of the battery, and the output end is connected to the input end of the AFE acquisition chip; The input end of the sampling resistor responds to the detection current at the negative electrode of the battery, converts the detection current into a detection voltage, and the output end of the sampling resistor transmits the detection voltage to the input end of the detection module; When the detection voltage is greater than or equal to the preset threshold voltage, the detection voltage is the first detection voltage, and the input end of the AFE acquisition chip responds to the first detection voltage and transmits the first detection voltage to the input end of the control module.

[0032] Figure 2 This is the circuit schematic diagram of the engine load-dump high-voltage surge suppression circuit provided by this application.

[0033] For Figure 2 the corresponding descriptions of the symbols of each electronic component involved in Figure 2 are as shown below. The meanings are the same hereinafter and will not be marked and elaborated again. For example,

[0034] In the embodiment of this application, the detection module in the engine load-dump high-voltage surge suppression circuit includes: a sampling resistor and an AFE (Analog Front End) acquisition chip. Among them, the input end of the sampling resistor is connected to the negative electrode of the battery and is used to receive the current signal flowing through the negative electrode of the battery, and the output end of the sampling resistor is connected to the input end of the AFE acquisition chip.

[0035] During the specific working process, when the battery is in a discharging or charging state, there is an actual current flow at its negative electrode. The sampling resistor responds to this detected current and converts the current flowing through it into a corresponding voltage signal based on Ohm's law (U = IR), that is, a detection voltage is generated. This detection voltage changes with the magnitude of the negative electrode current and can reflect the degree of current impact on the battery in the power supply circuit.

[0036] The output terminal of the sampling resistor transmits this detection voltage to the input terminal of the AFE acquisition chip in real time. The AFE chip collects, filters, and performs A / D conversion on the received detection voltage, and outputs the converted voltage value to the control module for subsequent judgment.

[0037] When the detection voltage is greater than or equal to the preset threshold voltage, the system determines that the current working state of the battery is abnormal, and the detection voltage is then recognized as the first detection voltage. After responding to this first detection voltage, the AFE acquisition chip immediately outputs it to the input terminal of the control module as the criterion for triggering the load dump protection.

[0038] Through the above structure, the detection module can accurately convert the current signal into voltage information, and achieve high-precision data acquisition and transmission with the help of the AFE chip, thereby providing a reliable basis for the load dump protection judgment of the control module. This structure is simple and has a fast response, and is applicable to the vehicle power management system that needs to monitor current anomalies in real time, effectively enhancing the system's ability to cope with surge voltages.

[0039] Further, the control module includes an MCU control chip, the discharge module includes a discharge signal unit, a discharge switch unit, and a discharge resistor, and the discharge switch unit includes a first end of the discharge switch unit, a control end of the discharge switch unit, and a second end of the discharge switch unit; The input terminal of the discharge signal unit is connected to the first output terminal of the control module, and the output terminal is connected to the negative electrode of the battery; The first end of the discharge switch unit is connected to the first end of the discharge resistor, the control end of the discharge switch unit is connected to the positive electrode of the battery, and the second end of the discharge switch unit is connected to the output terminal of the discharge signal unit; The second end of the discharge resistor is connected to the first end of the discharge switch unit; The control end of the discharge switch unit responds to the voltage of the positive electrode of the battery to turn on the discharge switch unit, so that the first end of the discharge resistor is connected to the positive electrode of the battery, the second end of the discharge resistor is connected to the negative electrode of the battery, and the discharge resistor is connected in parallel with the battery.

[0040] In the embodiment of the present application, the control module includes an MCU control chip, and the discharge module includes: a discharge signal unit, a discharge switch unit, and a discharge resistor. Among them, the discharge switch unit usually adopts an N-channel MOS transistor, the first end of the discharge unit is the source electrode, the control end of the discharge unit is the gate electrode, and the second end of the discharge unit is the drain electrode.

[0041] In practical applications, the MCU control chip, as the core device of the control module, has its first output terminal electrically connected to the input terminal of the discharge signal unit for outputting a control signal; the output terminal of the discharge signal unit is connected to the negative electrode of the battery to form a discharge path.

[0042] The first end of the discharge switch unit is connected to the first end of the discharge resistor to form a part of the current path; the control end of the discharge switch unit is connected to the positive electrode of the battery to receive the drive of the positive electrode voltage; the second end of the discharge switch unit is connected to the output terminal of the discharge signal unit, thereby finally realizing the connection to the negative electrode of the battery.

[0043] The second end of the discharge resistor is also connected to the first end of the discharge switch unit, enabling the discharge resistor to form a closed conduction path. This structure ensures that when the discharge switch unit is turned on, the discharge resistor is between the positive and negative electrodes of the battery, that is, in parallel with the battery.

[0044] In this embodiment, when the MCU control chip receives the first detection voltage from the detection module, it determines that there is an overvoltage or surge risk in the current system and then issues a first control signal. After being processed by the discharge signal unit, this signal guides the control end of the discharge switch unit to sense the voltage of the positive electrode of the battery, thereby realizing the rapid conduction of the switching device.

[0045] The discharge switch unit can adopt MOSFET or IGBT devices. After it is turned on, the positive electrode voltage of the battery flows to the negative electrode through the discharge resistor, thereby forming a parallel discharge path between the battery and the discharge resistor. This path is used to consume excess energy, absorb the high-voltage surge during the load-dump process, and reduce the impact on the battery pack and the power management system.

[0046] Through this structural design, the entire discharge control process features fast response speed, clear structure, and simple implementation, and can effectively improve the stability and safety of the vehicle electrical system under sudden working conditions, and is especially suitable for new energy vehicles, hybrid vehicles, and industrial engine systems.

[0047] Figure 2 It is a circuit schematic diagram of the engine load-dump high-voltage surge suppression circuit provided by this application.

[0048] Furthermore, the discharge signal unit includes a first resistor and an optocoupler; The input end of the first resistor is connected to the first output end of the control module, and the output end is connected to the input end of the optocoupler; The output end of the optocoupler is connected to the negative electrode of the battery and the second end of the discharge switch unit; The control end of the discharge switch unit conducts when the voltage of the positive electrode of the battery is at a high level. The first end of the discharge switch unit is conducted with the second end of the discharge switch unit, so that the first end of the discharge resistor is connected to the positive electrode of the battery, the second end of the discharge resistor is connected to the negative electrode of the battery, and the discharge resistor is connected in parallel with the battery.

[0049] In the embodiment of the present application, the structure and connection mode of the discharge signal unit are as follows: the input end of the first resistor is connected to the first output end of the control module (such as an MCU control chip) for receiving the first control signal from the control module; the output end of the first resistor is connected to the input end of the optocoupler for current limiting and level conversion; the output end of the optocoupler is connected to the negative electrode of the battery and the second end of the discharge switch unit.

[0050] When the positive electrode of the battery is in a high level state (such as 12V or a higher system voltage) and the output end of the optocoupler is pulled low, the discharge switch unit (such as an N-channel MOS transistor) satisfies the condition of Vgs > threshold voltage and conducts. After conduction, a low-resistance channel is formed between its first end and the second end. In this parallel circuit, the discharge resistor forms a complete circuit with the positive and negative electrodes of the battery, which is used to absorb the remaining charge or surge energy in the external circuit in the case of load dumping, avoid high-voltage impact damage to system devices, and ensure the stability and safety of the vehicle power system.

[0051] The above structural design enables the control signal to be transmitted through the optoelectronic isolation method, ensuring the electrical isolation between the MCU and the high-voltage side. The discharge action is controlled by the optocoupler to control the low-end switch. The structure is safe and reliable, the parallel discharge path conducts quickly and responds sensitively, and it is suitable for scenarios with fast response to voltage surges.

[0052] Further, the discharge module further includes a second resistor, a first NPN-type triode, a third resistor, a first PNP-type triode, a first crystal diode, a second crystal diode, and a fourth resistor.

[0053] The input end of the second resistor is connected to the positive electrode of the battery, and the output end is connected to the collector of the first NPN-type triode; The emitter of the first NPN-type triode is connected to the input end of the third resistor; The output end of the third resistor is connected to the emitter of the first PNP-type triode; The collector of the first PNP-type triode is connected to the positive electrode of the first crystal diode; The negative electrode of the first crystal diode is connected to the positive electrode of the second crystal diode; The negative electrode of the second crystal diode is connected to the input end of the fourth resistor; The output end of the fourth resistor is connected to the control end of the discharge switch unit.

[0054] In the embodiment of the present application, to further enhance the response ability of the discharge module to the load-dump high-voltage surge under different working conditions, on the basis of the foregoing discharge module, a multi-stage voltage control and trigger structure is further introduced, including: a second resistor, a first NPN-type triode, a third resistor, a first PNP-type triode, a first crystal diode, a second crystal diode, and a fourth resistor.

[0055] The above-mentioned devices constitute an auxiliary trigger circuit for controlling the conduction state of the discharge switch unit, and its structure and functions are as follows: The input end of the second resistor is connected to the positive electrode of the battery, and the output end is connected to the collector of the first NPN-type triode. This second resistor is used for current limiting and providing a suitable bias voltage for the NPN triode. The emitter of the first NPN-type triode is connected to the input end of the third resistor; the output end of the third resistor is then connected to the emitter of the first PNP-type triode. This structure constitutes a voltage-driven amplification chain for realizing the conduction control of the PNP transistor. The collector of the first PNP-type triode is connected to the positive electrode of the first crystal diode to form a signal transmission path; the negative electrode of the first crystal diode is connected to the positive electrode of the second crystal diode, and the two-stage diodes are connected in series to limit the voltage direction and protect the subsequent devices.

[0056] The negative electrode of the second crystal diode is connected to the input end of the fourth resistor, and the output end of the fourth resistor is finally connected to the control end (Gate end) of the discharge switch unit. Through the above circuit structure, when a high-level signal appears at the positive electrode of the battery, the voltage enters the first NPN-type triode through the second resistor. If this voltage reaches the bias condition for the NPN transistor to turn on, after its conduction, it will introduce the emitter current into the third resistor and trigger the conduction of the PNP-type triode. After the PNP-type triode conducts, the voltage output from its collector forms a unidirectional path through the first and second crystal diodes, and after being limited by the fourth resistor, it is sent to the control end of the discharge switch unit. After receiving the stable driving voltage from the PNP transistor, this control end makes the discharge switch unit conduct reliably.

[0057] The auxiliary circuit design has the following advantages: A stable voltage amplification and isolation stage is formed by transistors, which improves the driving ability. Diodes in series provide unidirectional conduction protection to avoid reverse breakdown. Resistors are used for current limiting to ensure the safety of pin currents at all levels and prevent overshoot of the driving voltage. The overall structure enhances the anti-interference ability and response accuracy of the discharge control channel, meeting the requirement of rapid surge peak shaving in the load-dump scenario. This structure is especially suitable for power modules in high-voltage systems with frequent load-dump processes and high protection accuracy requirements, and can be used as one of the key protection branches in the engine power management system.

[0058] Further, the control module further includes a charging switch unit. When the discharge switch unit is turned on and the discharge resistor is connected in parallel with the battery, the second output terminal of the MCU control chip outputs a second signal and transmits the second signal to the charging switch unit. The charging switch unit responds to the second signal and turns off, so as to disconnect the external circuit from the battery.

[0059] Further, the charging switch unit includes a first end of the charging switch unit, a control end of the charging switch unit, and a second end of the charging switch unit. The first end of the charging switch unit is connected to the external circuit, the second end of the charging switch unit is connected to the negative electrode of the battery, and the control end of the charging switch unit is connected to the second output terminal of the MCU control chip. The control end of the charging switch unit responds to the second signal and disconnects the connection between the first end and the second end of the charging switch unit, so as to disconnect the negative electrode of the external circuit from the negative electrode of the battery and stop the external circuit from charging the battery.

[0060] To further improve the overall response ability and circuit safety of the load-dump high-voltage surge suppression circuit, a charging switch unit is introduced in the control module in this embodiment. After the discharge resistor and the battery form a parallel circuit, the connection between the external circuit and the battery is timely cut off to prevent the system from being unstable or malfunctioning due to continuous charging during the surge.

[0061] Specifically, the control module not only includes the MCU control chip and the aforementioned first output terminal linked to the discharge module, but also includes a second output terminal for controlling charging and discharging. After the MCU control chip detects the load-dump state and turns on the discharge switch unit, its second output terminal outputs a second signal, which is transmitted to the charging switch unit to control its operation.

[0062] The charging switch unit includes: a first end of the charging switch unit, used to be connected to the negative end of the external circuit; a second end of the charging switch unit, connected to the negative pole of the battery; and a control end of the charging switch unit, used to receive a second signal from the second output end of the MCU.

[0063] Under normal working conditions, the charging switch unit is turned on, and the external circuit forms a closed charging loop with the negative electrode of the battery through it. When it is detected that the engine system enters the load dump state, the control module controls the discharge switch unit to be turned on through the first output terminal, so that the discharge resistor and the battery form a parallel path to receive the residual energy in the external circuit; at the same time, the second output terminal of the MCU control chip outputs a high level or a shutdown signal (i.e., the second signal), triggering the charging switch unit to operate.

[0064] After receiving the second signal, the charging switch unit responds by shutting off the conduction state between the first end and the second end, that is, disconnecting the connection between the negative electrode of the external circuit and the negative electrode of the battery, thereby achieving the following goals: Avoid the external circuit still supplying energy to the battery during the load dump process, causing the risk of system mischarging or recharging. Achieve power-off isolation of the external load and improve the safety recovery capability of the system after the overall surge response. Work together with the discharge module to form a complete surge control and power switching path.

[0065] Preferably, the charging switch unit can be composed of a MOSFET device with fast response capability. When its control terminal receives a second signal (such as a low level), the connection between its Source terminal (connected to the negative electrode of the battery) and the Drain terminal (connected to the external load) is cut off, thereby forming an effective electrical disconnection.

[0066] The control strategy in this embodiment realizes the dual response of "surge discharge + load disconnection", improves the electrical isolation efficiency and system reliability during the load dumping process, and is suitable for scenarios such as new energy vehicle engine power supply system, hybrid system high-voltage side load management, and industrial power generation system power supply protection.

[0067] Furthermore, the control module also includes a fifth resistor, a second NPN-type transistor, a sixth resistor, a second PNP-type transistor, a third crystal diode, a fourth crystal diode and a seventh resistor.

[0068] Furthermore, the input end of the fifth resistor is connected to the second output end of the MCU control chip, and the output end is connected to the base of the second NPN transistor; The collector of the second NPN transistor is connected to the input end of the sixth resistor; The output end of the sixth resistor is connected to the base of the second PNP transistor; The collector of the second PNP transistor is connected to the anode of the third crystal diode; The negative electrode of the third crystal diode is connected to the positive electrode of the fourth crystal diode; The negative electrode of the fourth crystal diode is connected to the input end of the seventh resistor; The output end of the seventh resistor is connected to the control end of the charging switch unit.

[0069] In the embodiment of the present application, in order to improve the control accuracy and driving ability of the control module for the charging switch unit, in this embodiment, a signal amplification and isolation driving circuit composed of a transistor, a resistor and a diode is further provided to realize the effective level output of the control end of the charging switch unit.

[0070] The circuit structure includes the following components: a fifth resistor, a second NPN-type triode, a sixth resistor, a second PNP-type triode, a third crystal diode, a fourth crystal diode, and a seventh resistor.

[0071] The circuit connection relationship formed by the above devices is as follows: the input end of the fifth resistor is connected to the second output end of the MCU control chip, and the output end is connected to the base of the second NPN-type triode. This structure is used for current limiting and providing a bias voltage to control the conduction of the second NPN-type triode.

[0072] The collector of the second NPN-type triode is connected to the input end of the sixth resistor to form a current path. The output end of the sixth resistor is connected to the base of the second PNP-type triode to provide a bias current to drive the PNP triode.

[0073] The collector of the second PNP-type triode is connected to the positive electrode of the third crystal diode. The negative electrode of the third crystal diode is connected to the positive electrode of the fourth crystal diode. The diodes are connected in series for direction control and preventing reverse breakdown.

[0074] The negative electrode of the fourth crystal diode is connected to the input end of the seventh resistor. Finally, the output end of the seventh resistor is connected to the control end of the charging switch unit.

[0075] The specific working process of this circuit is as follows: when the second output end of the MCU control chip detects a load dump situation and issues a control signal (the second signal), this electrical signal is input to the base of the second NPN-type triode after current limiting by the fifth resistor; the second NPN-type triode conducts after obtaining sufficient bias voltage, and a current path is formed between its collector and emitter, driving a voltage drop across the sixth resistor; this voltage drop is applied to the base of the second PNP-type triode to make it conduct, and the output voltage of the collector is transmitted to the seventh resistor after passing through the series-connected third and fourth crystal diodes; the seventh resistor further limits the current and transmits this signal voltage to the control end of the charging switch unit to control its state to become off.

[0076] The structural design has the following advantages: By constructing a voltage amplification and level isolation chain with two-stage triodes, the signal driving strength and anti-interference ability are improved. The series-connected crystal diodes provide a unidirectional conduction path and protect the output terminal of the PNP transistor from reverse breakdown. The multi-stage current-limiting resistors ensure the current safety of each stage of the circuit and are suitable for a variety of working voltage ranges. It can ensure that when the output driving ability of the MCU control chip is limited, the charging switch unit can still be reliably driven, improving the response timeliness and robustness of the overall system.

[0077] Through the above structural settings, the MCU control module can implement linkage control over the discharge path and the external load circuit. When a load dump surge occurs, it can not only safely release energy through the discharge module but also disconnect the charging path through the charging switch unit to avoid risks such as mischarging and breakdown, comprehensively improving the safety performance and control intelligence level of the high-voltage system.

[0078] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0079] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the essence of the above technical solution, or the part that contributes to the related technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0080] It should be understood that the terms used in this document are only for the purpose of describing specific example embodiments and are not intended to be restrictive. Unless otherwise clearly specified in the context, the singular forms "a", "an", and "the" as used in this document may also represent the plural form. The terms "include", "comprise", "contain", and "have" are inclusive and thus specify the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or their combinations. The method steps, processes, and operations described in this document are not to be construed as necessarily requiring them to be executed in the specific order described or illustrated, unless the execution order is clearly specified. It should also be understood that alternative or additional steps can be used.

[0081] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A high-voltage surge suppression circuit for an engine's load rejection, characterized in that, The engine load - shedding high - voltage surge suppression circuit includes a detection module, a control module, and a discharge module; The input end of the detection module is connected to the negative pole of the battery, and the output end is connected to the input end of the control module; The first output end of the control module is connected to the first input end of the discharge module; The output end of the discharge module is connected to the external circuit of the engine; The detection module responds to a first detection voltage and transmits the first detection voltage to the input end of the control module, where the first detection voltage is a voltage greater than a preset threshold voltage; The input end of the control module responds to the first detection voltage, and the output end of the control module outputs a first signal; The first input end of the discharge module responds to the first signal and conducts, so that the second end of the discharge module is connected to the positive pole of the battery, and the third end of the discharge module is connected to the negative pole of the battery, forming a parallel circuit of the discharge module and the battery, so that the discharge module serves as a load of the external circuit for the external circuit to discharge.

2. The high-voltage surge suppression circuit for engine load rejection according to claim 1, characterized in that, The detection module includes a sampling resistor and an AFE acquisition chip; The input end of the sampling resistor is connected to the negative pole of the battery, and the output end is connected to the input end of the AFE acquisition chip; The input end of the sampling resistor responds to the detection current of the negative pole of the battery, converts the detection current into a detection voltage, and the output end of the sampling resistor transmits the detection voltage to the input end of the detection module; When the detection voltage is greater than or equal to the preset threshold voltage, the detection voltage is the first detection voltage, and the input end of the AFE acquisition chip responds to the first detection voltage and transmits the first detection voltage to the input end of the control module.

3. The high-voltage surge suppression circuit for engine load rejection according to claim 2, wherein The control module includes an MCU control chip, the discharge module includes a discharge signal unit, a discharge switch unit, and a discharge resistor, and the discharge switch unit includes a first end of the discharge switch unit, a control end of the discharge switch unit, and a second end of the discharge switch unit; The input end of the discharge signal unit is connected to the first output end of the control module, and the output end is connected to the negative pole of the battery; The first end of the discharge switch unit is connected to the first end of the discharge resistor, the control end of the discharge switch unit is connected to the positive pole of the battery, and the second end of the discharge switch unit is connected to the output end of the discharge signal unit; The second end of the discharge resistor is connected to the first end of the discharge switch unit; The control end of the discharge switch unit responds to the voltage of the positive pole of the battery and conducts the discharge switch unit, so that the first end of the discharge resistor is connected to the positive pole of the battery, the second end of the discharge resistor is connected to the negative pole of the battery, and the discharge resistor is in parallel with the battery.

4. The high-voltage surge suppression circuit for engine load shedding according to claim 3, characterized in that, The discharge signal unit includes a first resistor and an optocoupler; The input end of the first resistor is connected to the first output end of the control module, and the output end is connected to the input end of the optocoupler; The output end of the optocoupler is connected to the negative pole of the battery and the second end of the discharge switch unit; The control terminal of the discharge switch unit is turned on in response to the high voltage level of the positive electrode of the battery. The first end of the discharge switch unit is connected to the second end of the discharge switch unit, so that the first end of the discharge resistor is connected to the positive electrode of the battery, the second end of the discharge resistor is connected to the negative electrode of the battery, and the discharge resistor is connected in parallel with the battery.

5. The high-voltage surge suppression circuit for engine load rejection according to claim 4, wherein The discharge module further includes a second resistor, a first NPN transistor, a third resistor, a first PNP transistor, a first crystal diode, a second crystal diode, and a fourth resistor.

6. The engine load-dump high-voltage surge suppression circuit according to claim 5, wherein The input end of the second resistor is connected to the positive electrode of the battery, and the output end is connected to the collector of the first NPN transistor; The emitter of the first NPN transistor is connected to the input end of the third resistor; The output end of the third resistor is connected to the emitter of the first PNP transistor; The collector of the first PNP transistor is connected to the positive electrode of the first crystal diode; The negative electrode of the first crystal diode is connected to the positive electrode of the second crystal diode; The negative electrode of the second crystal diode is connected to the input end of the fourth resistor; The output end of the fourth resistor is connected to the control terminal of the discharge switch unit.

7. The high-voltage surge suppression circuit for engine load shedding according to claim 3, characterized in that The control module further includes a charging switch unit. When the discharge switch unit is turned on and the discharge resistor is connected in parallel with the battery, the second output terminal of the MCU control chip outputs a second signal and transmits the second signal to the charging switch unit; The charging switch unit is turned off in response to the second signal, so that the external circuit is disconnected from the battery.

8. The high-voltage surge suppression circuit for engine load shedding according to claim 7, wherein, The charging switch unit includes a first end of the charging switch unit, a control terminal of the charging switch unit, and a second end of the charging switch unit; The first end of the charging switch unit is connected to the external circuit, the second end of the charging switch unit is connected to the negative electrode of the battery, and the control terminal of the charging switch unit is connected to the second output terminal of the MCU control chip; The control terminal of the charging switch unit disconnects the connection between the first end of the charging switch unit and the second end of the charging switch unit in response to the second signal, so as to disconnect the negative electrode of the external circuit from the negative electrode of the battery and stop the external circuit from charging the battery.

9. The high-voltage surge suppression circuit for engine load shedding according to claim 7, characterized in that, The control module further includes a fifth resistor, a second NPN transistor, a sixth resistor, a second PNP transistor, a third crystal diode, a fourth crystal diode, and a seventh resistor.

10. The engine load-dump high-voltage surge suppression circuit according to claim 9, wherein The input end of the fifth resistor is connected to the second output terminal of the MCU control chip, and the output end is connected to the base of the second NPN transistor; The collector of the second NPN transistor is connected to the input end of the sixth resistor; The output end of the sixth resistor is connected to the base of the second PNP transistor; The collector of the second PNP transistor is connected to the positive electrode of the third crystal diode; The negative electrode of the third crystal diode is connected to the positive electrode of the fourth crystal diode; The negative electrode of the fourth crystal diode is connected to the input end of the seventh resistor; The output end of the seventh resistor is connected to the control end of the charging switch unit.

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