Storage battery power shortage protection circuit of artillery power supply electrical system

Abstract

The invention discloses a storage battery power shortage protection circuit of an artillery power supply electrical system, which comprises a voltage sampling unit, a power shortage judgment and control unit and an electronic switch unit, and is characterized in that the voltage sampling unit is used for sampling power supply voltage of a storage battery and setting a power shortage protection point threshold value through a resistance network; a power supply sampling voltage is provided for the power shortage judgment and control unit; a comparison circuit of the power shortage judgment and control unit compares a sampled power supply voltage with an internal reference voltage, controls the on-off of a two-stage triode common emitter circuit of the post-stage driving amplification circuit through the on-off of an internal triode, and controls the power-on or power-off of a relay coil of the electronic switch unit. Therefore, the normally open contact of the relay is used as an electronic switch to realize the power distribution control of the equipment mounted on the artillery power supply system. The storage battery power shortage protection circuit provided by the invention has the characteristics of adjustable threshold value, extremely low power consumption, strong anti-interference capability and high reliability.

Description

Technical Field

[0001] The present invention and the field of artillery power supply electrical technology specifically relate to a battery low-power protection circuit for a artillery power supply electrical system. Background Art

[0002] At present, many artillery power supply electrical systems generally use generators and batteries to connect to the grid for power supply, where the generator can be a main generator or an auxiliary generator. When the upper equipment is powered only by batteries, if the vehicle engine is started at this time, or high-power electrical equipment such as gun adjustment and loading (such as follow-up system, ammunition supply and delivery system) is working, it will cause problems such as restarting the upper equipment; at the same time, there is also the possibility that the upper equipment will use electricity for a long time, causing the battery to be depleted, thus affecting the normal starting of the vehicle.

[0003] In order to avoid such problems, the general artillery power supply system is designed with a dedicated battery for the upper part, which can power the upper part equipment alone or work in parallel with the generator. When connected to the generator, the generator charges the battery; to ensure the independence of the chassis power supply and the upper part power supply, the upper part and the chassis are controlled by different main power switches; however, when this power supply system is used, when only the upper part battery is used for power supply, during system debugging and training, if the operator forgets to turn off the "upper part main power" switch, the battery will power the electrical equipment for a long time, causing the battery to be seriously depleted, affecting the normal use of the equipment. Existing artillery power supply systems are generally only designed with power supply voltage indication and low voltage alarm prompts, and there is no battery undervoltage protection function, which poses a risk of serious battery depletion. Summary of the invention

[0004] The purpose of the present invention is to provide a battery low-power protection circuit for a gun power supply electrical system, which has an adjustable threshold, extremely low power consumption, strong anti-interference ability and high reliability.

[0005] In order to achieve the above tasks, the present invention adopts the following technical solutions:

[0006] A battery power failure protection circuit for a gun power supply electrical system includes a voltage sampling unit, a power failure judgment and control unit, and an electronic switch unit, wherein:

[0007] The voltage sampling unit samples the power supply voltage of the battery and sets the threshold value of the power-deficient protection point through a resistor network, providing the power supply sampling voltage for the power-deficient judgment and control unit;

[0008] The comparison circuit of the power failure judgment and control unit compares the sampled power supply voltage with its internal reference voltage, and controls the conduction and cutoff of the two-stage transistor common emitter circuit of the subsequent drive amplifier circuit through the on-off of its internal transistor, thereby controlling the power on or off of the relay coil of the electronic switch unit, thereby using the normally open contacts of the relay as an electronic switch to realize power distribution control of the equipment on the artillery power supply system.

[0009] Furthermore, the voltage sampling unit is composed of a voltage divider network composed of resistors R1, R4, R8, and a diode D2, and a voltage sampling anti-interference branch composed of a resistor R8 and a capacitor C1, wherein: the resistor R8 and the capacitor C1 are connected in parallel and then connected in series with the resistor R1, the resistor R4, and the switching diode D2 at the positive and negative ends of the battery, the positive electrode of the switching diode D2 is connected to the resistor R4, and the negative electrode of the switching diode D2 is connected to the resistor R8.

[0010] Furthermore, the comparison circuit of the power-deficit judgment and control unit includes a controllable precision voltage regulator U2, and U2 adopts a TL431 chip; the cathode of the switching diode D2 is connected to the REF terminal of U2, and the ANODE of U2 is connected to the negative pole of the battery power supply; the post-stage driving amplifier circuit of the power-deficit judgment and control unit is composed of two triode common-emitter circuits, wherein the resistor R2, the resistor R6 and the triode Q2 constitute the first-stage triode common-emitter circuit, and the resistor R3, the resistor R5 and the triode Q1 constitute the second-stage triode common-emitter circuit; one end of R2 is connected to the positive pole of the battery power supply, and the other end of R2 is connected to one end of R6, one end of R7 and the CATHODE terminal of U2; the other end of R6 is connected to the base of Q2, the other end of R7 is connected to the collector of Q1, and R5 is connected between the collector of Q2 and the base of Q1; the collector of Q2 is connected to the positive pole of the battery power supply through R3, and the emitters of Q1 and Q2 are both connected to the negative pole of the battery power supply.

[0011] Furthermore, the electronic switch unit is composed of a relay U1 and a diode D1, wherein the positive pole of D1 is connected to the collector of Q1, and the negative pole of D1 is connected to the positive pole of the battery power supply; D1 is connected in parallel with the coil of the relay U1, one end of the normally open contact of U1 is connected to the load, and the other end of the normally open contact is switched between the floating end and the wiring terminal; the wiring terminal is connected to the positive pole of the battery power supply.

[0012] Furthermore, by adjusting the resistors R1, R4, and R8, the voltage value U of the battery undervoltage protection point can be adjusted according to the reference voltage configured at the REF terminal of the controllable precision voltage regulator U2. th-bat .

[0013] Furthermore, since the interference signal of the power supply sampling voltage is a voltage drop signal within the pulse width T0, and the amplitude reaches 16V, in order to suppress and eliminate the interference of the interference signal, it is necessary to design t>T0, and take t=1s; according to the recommended working current of 1~100mA input at the REF terminal of U2, select R8 as 5.1KΩ; the bypass capacitor C1 and R8 form a discharge loop, and the time required for the bypass capacitor to discharge to 10% of the original is:

[0014] t=2.302R8C1

[0015] From the above formula, we can get C1≈100μF; when the battery power voltage drops to the battery undervoltage protection point voltage value U th-bat , after the resistor divider, the voltage at point A is equal to 2.5V, satisfying:

[0016]

[0017] From the above formula, we can calculate that R1+R4≈36KΩ, so we select R1=33KΩ and R4=2.7KΩ.

[0018] Furthermore, the power supply voltage of the battery is input to the voltage sampling unit, which realizes automatic sampling of the power supply voltage of the battery and setting of the threshold value of the power-down protection point through the voltage division of the resistors R1 and R4; the power supply sampling voltage of the battery is output to the power-down judgment and control unit as the input signal of the comparison circuit of the controllable precision voltage regulator U2, and the signal is compared with the 2.5V reference voltage inside the comparison circuit to control the saturation conduction or cutoff of the internal transistor, and the output signal of U2 controls the conduction and cutoff of the transistors Q1 and Q2 of the subsequent driving amplifier circuit; the electronic switch unit includes a relay, and the output signal of the driving amplifier circuit controls the coil of the relay, thereby The normally open contact of the relay is used as an electronic switch to realize the power distribution control of the load of the artillery power supply system; when the power supply voltage of the battery is greater than the set power-loss protection point threshold, the input voltage of the REF terminal of U2 is greater than the reference voltage configured by U2, the transistor Q1 is turned on, Q2 is turned off, and the relay coil is energized to connect the normally open contact, thereby ensuring normal power distribution to the load; when the power supply voltage of the battery is lower than the set power-loss protection point threshold, the input voltage of the REF terminal of U2 is less than the reference voltage, the transistor Q1 is turned off, Q2 is turned on, the relay coil loses power, and the normally open contact switches to the floating end, thereby automatically cutting off the load and avoiding serious power loss of the battery.

[0019] Furthermore, when the battery low-power protection circuit is applied to a vehicle-mounted artillery, the normally open contact of the relay U1 is connected in series with the main power switch as an electronic switch, and a manual shielding switch is arranged in parallel outside the electronic switch; a contactor KM is arranged, one end of the coil of the contactor KM is connected to the positive power pole of the battery, and the other end of the coil is connected to the main power switch; the normally open contact of the contactor KM is arranged on the load power supply line, one end of the load power supply line is connected to the positive power pole of the battery, and the other end is connected to each load through a plurality of load power supply branches, and a fuse FU is arranged on the load power supply line; the load power-on switch can also be set on each load power supply branch according to actual application requirements.

[0020] Furthermore, the diode D2 is 1N4148, the resistor R1 is 33kΩ, R4 is 2.7kΩ, R8 is 5.1kΩ, and the capacitor C1 is 100μF; the transistors Q1 and Q2 are 2N3904, the resistance values ​​of R2 and R3 are 10kΩ, R5 is 100kΩ, and R6 is 51kΩ; the relay U1 is JZC56MA; the battery low power protection point threshold U th-bat Set to 22V, when the power sampling voltage U i Equal to U th-bat When the switching diode D2 and the resistor R8 are connected, a point A is selected as the sampling point. The potential at point A is U A is 2.5V; when the power sampling voltage U i When it is less than 22V, the potential U A Less than 2.5V, the REF pin voltage of TL431 is less than 2.5V.

[0021] Furthermore, by adjusting the resistors R1, R4, and R8, the battery low-power protection point threshold U can be adjusted according to the reference voltage of the REF terminal of U2 being 2.5V. th-bat By adjusting the transistor Q1 model, the driving capability of the subsequent driving amplifier circuit can be adjusted to adapt to different relay requirements.

[0022] Compared with the prior art, the present invention has the following technical features:

[0023] 1. The battery voltage is sampled through resistor voltage division, the battery power-deficient threshold is set, and the voltage is compared through the controllable precision voltage regulator TL431 to determine whether the battery is power-deficient. The circuit driving ability is improved through a two-stage transistor cascade circuit, and the power distribution control of the load circuit is realized through a relay; it can automatically detect the battery voltage status. When the power supply voltage is lower than the set threshold, the relay contacts are used as an electronic switch to automatically cut off the load power distribution circuit to prevent the battery from further power loss and damage, thus realizing the undervoltage protection function of the battery.

[0024] 2. By adjusting the voltage-dividing resistor ratio, the undervoltage protection point threshold can be adjusted, making the threshold adjustable and suitable for the actual needs of different equipment.

[0025] 3. Use capacitor and resistor parallel branches to suppress sampling voltage coupling interference signals, prevent relay malfunction, and improve the reliability of the protection circuit.

[0026] 4. Use low-power controllable precision voltage regulator and transistor to reduce the power consumption of the protection circuit itself, and minimize the consumption of battery power while meeting the requirements of online real-time monitoring of battery status. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a battery power-loss protection circuit diagram of the present invention;

[0028] Figure 2 The circuit diagram of the preferred embodiment of the battery power failure protection circuit of the present invention;

[0029] Figure 3 The voltage waveforms are illustrated to illustrate the principles of the present invention. DETAILED DESCRIPTION

[0030] The present invention provides a battery low-power protection circuit for a cannon power supply electrical system. The circuit automatically monitors the battery voltage. When the power supply voltage is lower than a set threshold, the load of a power distribution circuit is automatically cut off through an electronic switch to prevent the battery from being damaged by further low power. The modular design is adopted to meet the battery low-power protection requirements of various cannons and tank armored vehicle power supply systems.

[0031] See attached Figure 1 The present invention provides a battery power failure protection circuit for a gun power supply electrical system, comprising a voltage sampling unit, a power failure judgment and control unit, and an electronic switch unit, wherein:

[0032] 1. Voltage sampling unit

[0033] The voltage sampling unit samples the battery power voltage and sets the low-power protection point threshold through a resistor network, providing the power sampling voltage for the low-power judgment and control unit. In order to improve the anti-interference ability of the protection circuit and avoid false protection, the anti-interference design is implemented through a capacitor charging and discharging circuit.

[0034] See also Figure 1In one embodiment of the present invention, the voltage sampling unit is composed of a voltage divider network composed of resistors R1, R4, R8, and a diode D2, and a voltage sampling anti-interference branch composed of a resistor R8 and a capacitor C1, wherein: the resistor R8 and the capacitor C1 are connected in parallel and connected in series with the resistor R1, the resistor R4, and the switch diode D2 at the positive and negative ends of the battery, the positive electrode of the switch diode D2 is connected to the resistor R4, and the negative electrode of the switch diode D2 is connected to the resistor R8; a point A is taken between the switch diode D2 and the resistor R8 as a sampling point, and the power supply sampling voltage is drawn from point A.

[0035] The power failure protection threshold required by the user is U th-bat , when the battery power supply voltage U i Greater than U th-bat , then the power supply sampling voltage U A Greater than 2.5V; when U i Less than U th-bat , then U A Less than 2.5V.

[0036] 2. Power-loss judgment and control unit

[0037] The comparison circuit of the power failure judgment and control unit compares the sampled power supply voltage with its internal reference voltage, and controls the conduction and cutoff of the two-stage transistor common emitter circuit of the subsequent drive amplifier circuit through the on-off of its internal transistor, thereby controlling the power on or off of the relay coil of the electronic switch unit, thereby using the normally open contacts of the relay as an electronic switch to realize power distribution control of the equipment on the artillery power supply system.

[0038] The comparison circuit of the power-deficit judgment and control unit is composed of a controllable precision voltage-stabilizing source U2, and in this embodiment, U2 adopts a TL431 chip; the cathode of the switching diode D2 is connected to the REF terminal of U2, and the ANODE of U2 is connected to the negative pole of the battery power supply; the post-stage driving amplifier circuit of the power-deficit judgment and control unit is composed of two triode common-emitter circuits, wherein the resistor R2, the resistor R6 and the triode Q2 constitute the first-stage triode common-emitter circuit, and the resistor R3, the resistor R5 and the triode Q1 constitute the second-stage triode common-emitter circuit; one end of R2 is connected to the positive pole of the battery power supply, and the other end of R2 is connected to one end of R6, one end of R7 and the CATHODE terminal of U2; the other end of R6 is connected to the base of Q2, the other end of R7 is connected to the collector of Q1, and R5 is connected between the collector of Q2 and the base of Q1; the collector of Q2 is connected to the positive pole of the battery power supply through R3, and the emitters of Q1 and Q2 are both connected to the negative pole of the battery power supply.

[0039] For the sake of convenience, we take a point between R2 and R6 as B, a point between R3 and the collector of Q2 as C, and a point between the collector of Q1 and R7 as D. The power supply voltage sampled by the voltage sampling unit is input to the REF terminal of U2, and the reference voltage configured at the REF terminal is 2.5V; when the battery power supply voltage U i Greater than U th-bat , the voltage connected to the REF terminal of U2 is greater than 2.5V, the internal transistor of U2 is turned on, so that the ANODE terminal and CATHODE are connected, the potential of point B is clamped to 0V, no current flows into the base of Q2, and Q2 is cut off; the battery power supply U i The resistors R3 and R5 provide the base current for Q1, Q1 is saturated and turned on, and the potential at point D is clamped to 0V. i Less than U th-bat , the voltage connected to the REF terminal of U2 is less than 2.5V, the internal transistor of U2 is cut off, so that the ANODE terminal and the CATHODE terminal are disconnected, and the battery power provides base current to Q2 through resistors R2 and R6. Q2 is saturated and turned on, the potential at point C is clamped to 0V, no current flows into the base of Q1, and Q1 is cut off.

[0040] 3. Electronic switch unit

[0041] The electronic switch unit is composed of a relay U1 and a diode D1, wherein the positive pole of D1 is connected to the collector of Q1, and the negative pole of D1 is connected to the positive pole of the battery power supply; D1 is connected in parallel with the coil of relay U1, one end of the normally open contact of U1 (pin 7 in the figure) is connected to the load, and the other end of the normally open contact switches between the floating end (pin 2 in the figure) and the wiring terminal (pin 1 in the figure); the wiring terminal is connected to the positive pole of the battery power supply.

[0042] Diode D1 acts as a freewheeling diode to provide a freewheeling circuit for the coil when the relay U1 coil is powered off; the normally open contact of relay U1 realizes the electronic switch function, one end of the coil (pin 12 in the figure) is connected to the positive pole of the battery power supply, and the other end of the coil (pin 11 in the figure) is connected to the negative pole of the battery power supply through the collector and emitter of Q1; when Q1 is saturated and turned on, and the potential of point D is clamped to 0V, the voltage between pins 12 and 11 of relay U1 is the power supply voltage of the battery, and the coil is energized so that the normally open contact is attracted to the wiring terminal, that is, the electronic switch is turned on, and the load is powered normally when the main power switch is turned on; when Q1 is cut off, there is no voltage between pins 12 and 11 of relay U1, the coil loses power, the normally open contact switches to the floating end, and pins 1 and 7 of the relay are open, that is, the electronic switch is disconnected, disconnecting the load to prevent the battery from being seriously depleted.

[0043] In the application, by adjusting the resistors R1, R4, and R8, the reference voltage configured at the REF terminal of point A is 2.5V, and the voltage value U of the battery undervoltage protection point can be adjusted.th-bat .

[0044] The main circuit parameters are calculated as follows:

[0045] Since the sampling voltage interference signal is a voltage drop signal within the pulse width T0, with an amplitude of 16V, in order to suppress and eliminate the interference, it is necessary to design t>T0, and take t=1s; according to the recommended working current of 1~100mA input at the REF terminal of U2, select R8 as 5.1KΩ; bypass capacitors C1 and R8 form a discharge loop, and the time required for the bypass capacitor to discharge to 10% of the original value is:

[0046] t=2.302R8C1

[0047] From the above formula, we can get C1≈100μF; when the battery power voltage drops to U th-bat , after the resistor divider, the voltage at point A is equal to 2.5V, satisfying:

[0048]

[0049] From the above formula, we can calculate that R1+R4≈36KΩ, so we can approximately select R1=33KΩ and R4=2.7KΩ.

[0050] In summary, the protection circuit of the present invention, the power supply voltage input voltage sampling unit of the battery, realizes automatic sampling of the power supply voltage of the battery and setting of the threshold value of the power-down protection point through the voltage division of the resistors R1 and R4; the power supply sampling voltage of the battery is output to the power-down judgment and control unit as the input signal of the comparison circuit of the controllable precision voltage stabilizing source U2, and the signal is compared with the 2.5V reference voltage inside the comparison circuit to control the saturation conduction or cutoff of the internal transistor, and the output signal of U2 controls the conduction and cutoff of the transistors Q1 and Q2 of the subsequent driving amplifier circuit; the electronic switch unit includes a relay, and the output signal of the driving amplifier circuit controls the relay The coil of the device is connected, so that the normally open contact of the relay is used as an electronic switch to realize the power distribution control of the load of the artillery power supply system; when the power supply voltage of the battery is greater than the set power-loss protection point threshold, the input voltage of the REF terminal of U2 is greater than 2.5V, the transistor Q1 is turned on, Q2 is turned off, and the relay coil is energized to connect the normally open contact, thereby ensuring normal power distribution to the load; when the power supply voltage of the battery is lower than the set power-loss protection point threshold, the input voltage of the REF terminal of U2 is less than 2.5V, the transistor Q1 is turned off, Q2 is turned on, the relay coil loses power, and the normally open contact is switched to the floating end, thereby automatically cutting off the load and avoiding serious power loss of the battery.

[0051] Example:

[0052] See also Figure 2, which is an application of the battery low-power protection circuit of the present invention in a certain vehicle-mounted artillery, wherein the low-power protection circuit of the present invention is within the dotted frame.

[0053] When in use, the normally open contact of relay U1 is connected in series with the main power switch as an electronic switch, and a manual shielding switch is set in parallel outside the electronic switch; in addition, in order to avoid the influence of large current on relay U1, a contactor KM is set, one end of the coil of contactor KM is connected to the positive power pole of the battery, and the other end of the coil is connected to the main power switch; the normally open contact of contactor KM is set on the load power supply line, one end of the load power supply line is connected to the positive power pole of the battery, and the other end is connected to each load through multiple load power supply branches, and a fuse FU is set on the load power supply line; the load power-on switch can also be set on each load power supply branch according to actual application requirements.

[0054] exist Figure 2 In the given embodiment, the diode D2 is 1N4148, the resistor R1 is 33kΩ, R4 is 2.7kΩ, R8 is 5.1kΩ, and the capacitor C1 is 100μF; the transistors Q1 and Q2 are 2N3904, the resistance values ​​of R2 and R3 are 10kΩ, R5 is 100kΩ, and R6 is 51kΩ; the relay U1 is JZC56MA; the battery low power protection point threshold value U th-bat Set to 22V, when the power sampling voltage U i Equal to U th-bat When the potential at point A is U A is 2.5V; when the power sampling voltage U i When it is less than 22V, the potential U A Less than 2.5V, the REF pin voltage of TL431 is less than 2.5V.

[0055] In the application, by adjusting the resistors R1, R4, and R8, the reference voltage of the REF terminal of U2 is 2.5V, and the battery low-power protection point threshold U can be adjusted. th-bat By adjusting the transistor Q1 model, the driving capability of the subsequent driving amplifier circuit can be adjusted to adapt to different relay requirements.

[0056] like Figure 3As shown, the circuit working voltage waveform of this embodiment includes the negative pole voltage of the electronic switch coil (Vnegative pole of electronic switch coil), the negative pole voltage of the contactor coil (Vnegative pole of contactor coil), the positive pole voltage of the capacitor (Vcapacitor) and the voltage of the upper battery (Vbattery). At T0, C1 is charged, and the voltage reaches 2.5V at T1, and the coil of the relay is energized; at T2, the main power switch is closed, and the coil of the contactor is energized; when the interference pulse signal is introduced at T3, the C1 capacitor can make the voltage not less than 2.5V during T3-T4, and the electronic switch will not be disturbed and remain connected; at T4, the interference pulse ends, and C1 is recharged. The battery voltage starts to gradually decrease from T5, and when it drops to the critical value at T6, the C1 voltage is lower than 2.5V, the electronic switch is automatically disconnected, the contactor coil loses power, and all loads are automatically cut off.

[0057] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A battery power failure protection circuit for a gun power supply electrical system, characterized in that: It includes a voltage sampling unit, a power failure judgment and control unit, and an electronic switch unit, wherein: The voltage sampling unit samples the power supply voltage of the battery and sets the threshold value of the power-deficient protection point through a resistor network, providing the power supply sampling voltage for the power-deficient judgment and control unit; The comparison circuit of the power failure judgment and control unit compares the sampled power supply voltage with its internal reference voltage, and controls the conduction and cutoff of the two-stage transistor common emitter circuit of the subsequent drive amplifier circuit through the on-off of its internal transistor, thereby controlling the power on or off of the relay coil of the electronic switch unit, thereby using the normally open contacts of the relay as an electronic switch to realize power distribution control of the equipment on the artillery power supply system.

2. The battery power failure protection circuit of the artillery power supply electrical system according to claim 1 is characterized in that: The voltage sampling unit is composed of a voltage divider network composed of resistors R1, R4, R8, and a diode D2, and a voltage sampling anti-interference branch composed of a resistor R8 and a capacitor C1, wherein: the resistor R8 and the capacitor C1 are connected in parallel and connected in series with the resistor R1, the resistor R4, and the switching diode D2 at the positive and negative ends of the battery, the positive electrode of the switching diode D2 is connected to the resistor R4, and the negative electrode of the switching diode D2 is connected to the resistor R8.

3. The battery power failure protection circuit of the artillery power supply electrical system according to claim 1 is characterized in that: The comparison circuit of the power-deficit judgment and control unit includes a controllable precision voltage-stabilizing source U2, and U2 adopts a TL431 chip; the cathode of the switching diode D2 is connected to the REF terminal of U2, and the ANODE of U2 is connected to the negative pole of the battery power supply; the post-stage driving amplifier circuit of the power-deficit judgment and control unit is composed of two triode common-emitter circuits, wherein the resistor R2, the resistor R6 and the triode Q2 constitute the first-stage triode common-emitter circuit, and the resistor R3, the resistor R5 and the triode Q1 constitute the second-stage triode common-emitter circuit; one end of R2 is connected to the positive pole of the battery power supply, and the other end of R2 is connected to one end of R6, one end of R7 and the CATHODE terminal of U2; the other end of R6 is connected to the base of Q2, the other end of R7 is connected to the collector of Q1, and R5 is connected between the collector of Q2 and the base of Q1; the collector of Q2 is connected to the positive pole of the battery power supply through R3, and the emitters of Q1 and Q2 are both connected to the negative pole of the battery power supply.

4. The battery power failure protection circuit of the artillery power supply electrical system according to claim 1 is characterized in that: The electronic switch unit is composed of a relay U1 and a diode D1, wherein the positive pole of D1 is connected to the collector of Q1, and the negative pole of D1 is connected to the positive pole of the battery power supply; D1 is connected in parallel with the coil of the relay U1, one end of the normally open contact of U1 is connected to the load, and the other end of the normally open contact is switched between a suspended end and a wiring terminal; the wiring terminal is connected to the positive pole of the battery power supply.

5. The battery power failure protection circuit of the artillery power supply electrical system according to claim 1 is characterized in that: By adjusting the resistors R1, R4, and R8, the voltage value U of the battery undervoltage protection point can be adjusted according to the reference voltage configured at the REF terminal of the controllable precision voltage regulator U2. th-bat .

6. The battery power failure protection circuit of the artillery power supply electrical system according to claim 1 is characterized in that: Since the interference signal of the power sampling voltage is a voltage drop signal within the pulse width T0, with an amplitude of 16V, in order to suppress and eliminate the interference of the interference signal, it is necessary to design t>T0, and take t=1s; according to the recommended working current of 1~100mA input at the REF terminal of U2, select R8 as 5.1KΩ; bypass capacitors C1 and R8 form a discharge loop, and the time required for the bypass capacitor to discharge to 10% of the original value is: t=2.302R8C1 From the above formula, we can get C1≈100μF; when the battery power voltage drops to the battery undervoltage protection point voltage value U th-bat , after the resistor divider, the voltage at point A is equal to 2.5V, satisfying: From the above formula, we can calculate that R1+R4≈36KΩ, so we select R1=33KΩ and R4=2.7KΩ.

7. The battery power failure protection circuit of the artillery power supply electrical system according to claim 1 is characterized in that: The power supply voltage of the battery is input into the voltage sampling unit, which realizes automatic sampling of the power supply voltage of the battery and setting of the threshold value of the power-down protection point through the voltage division of resistors R1 and R4; the power supply sampling voltage of the battery is output to the power-down judgment and control unit as the input signal of the comparison circuit of the controllable precision voltage regulator U2, which is compared with the 2.5V reference voltage inside the comparison circuit to control the saturation conduction or cutoff of the internal triode, and the output signal of U2 controls the conduction and cutoff of the triodes Q1 and Q2 of the subsequent drive amplifier circuit; the electronic switch unit includes a relay, and the output signal of the drive amplifier circuit controls the coil of the relay, thereby turning the relay on and off. The normally open contact of the device is used as an electronic switch to realize the power distribution control of the load of the artillery power supply system; when the power supply voltage of the battery is greater than the set power-loss protection point threshold, the REF terminal input voltage of U2 is greater than the reference voltage configured by U2, the transistor Q1 is turned on, Q2 is turned off, and the relay coil is energized to connect the normally open contact, thereby ensuring normal power distribution to the load; when the power supply voltage of the battery is lower than the set power-loss protection point threshold, the REF terminal input voltage of U2 is less than the reference voltage, the transistor Q1 is turned off, Q2 is turned on, the relay coil loses power, and the normally open contact switches to the floating end, thereby automatically cutting off the load and avoiding serious power loss of the battery.

8. The battery power failure protection circuit of the artillery power supply electrical system according to claim 1 is characterized in that: When the battery low-power protection circuit is applied to a vehicle-mounted artillery, the normally open contact of the relay U1 is connected in series with the main power switch as an electronic switch, and a manual shielding switch is arranged in parallel outside the electronic switch; A contactor KM is provided, one end of the coil of the contactor KM is connected to the positive power pole of the battery, and the other end of the coil is connected to the main power switch; the normally open contact of the contactor KM is provided on the load power supply circuit, one end of the load power supply circuit is connected to the positive power pole of the battery, and the other end is connected to each load through a plurality of load power supply branches, and a fuse FU is provided on the load power supply circuit; the load power-on switch can also be set on each load power supply branch according to actual application requirements.

9. The battery power failure protection circuit of the artillery power supply electrical system according to claim 1 is characterized in that: The diode D2 model is 1N4148, the resistor R1 is 33kΩ, R4 is 2.7kΩ, R8 is 5.1kΩ, and the capacitor C1 is 100μF; the transistors Q1 and Q2 are 2N3904, the resistance values ​​of R2 and R3 are 10kΩ, R5 is 100kΩ, and R6 is 51kΩ; the relay U1 model is JZC56MA; the battery low power protection point threshold U th-bat Set to 22V, when the power sampling voltage U i Equal to U th-bat When the switching diode D2 and the resistor R8 are connected, a point A is selected as the sampling point. The potential at point A is U A is 2.5V; when the power sampling voltage U i When it is less than 22V, the potential U A Less than 2.5V, the REF pin voltage of TL431 is less than 2.5V.

10. By adjusting the resistors R1, R4, and R8, the battery low-power protection point threshold U can be adjusted according to the reference voltage of the REF terminal of U2 being 2.5V. th-bat By adjusting the transistor Q1 model, the driving capability of the subsequent driving amplifier circuit can be adjusted to adapt to different relay requirements.

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