Power lack protection circuit with emergency power-on function

Abstract

The utility model discloses an undervoltage protection circuit with an emergency power-on function, and belongs to the technical field of power supply of new energy locomotives. The utility model aims to solve the problem that the power-lack protector of the new energy locomotive cannot automatically reset. A storage battery is connected with a load through a default conduction pin of a magnetic latching relay; the storage battery is connected with a power-lack control coil of the magnetic latching relay through a resistor voltage division circuit, a capacitor charging and discharging circuit and a voltage comparator. A low-level output signal of the voltage comparator controls the conduction of a power-lack control coil of the magnetic latching relay, and a default conduction pin is disconnected, so that the storage battery is disconnected from the load, and the storage battery enters a power-lack protection state; when the inching button is pressed down, the storage battery charges a capacitor in the capacitor charging and discharging circuit, a high-level output signal of the voltage comparator controls a reset control coil of the magnetic latching relay to be switched on, meanwhile, a power-lack control coil is switched off, and a default switch-on pin is switched on, so that the storage battery is communicated with a load. The device is used for storage battery power shortage protection.

Description

Technical Field

[0001] The utility model relates to a power failure protection circuit with an emergency power-on function, belonging to the technical field of power supply for new energy locomotives. Background Art

[0002] The main energy source of a new energy locomotive comes from the high-voltage power battery on the vehicle, but all controllers for controlling the operation of the whole vehicle rely on the 24V low-voltage battery for power supply. When the whole vehicle starts, the battery can be charged by the high-voltage power battery. However, when the vehicle is parked for a long time, the controllers of each device will continuously consume the electric energy of the low-voltage battery, resulting in over-discharge of the low-voltage battery. The over-discharged battery may not be able to return to the normal working state, and even if it does, there are safety hazards. To solve the problem of over-discharge, a power failure protector can be used. As Figure 1 shown.

[0003] The power failure protector can automatically disconnect the load when the battery voltage is lower than a preset value. However, when the power failure protector enters the power failure protection state, to power on the system again, it is necessary to bypass the power failure protector by shielding the power failure protector circuit and directly supply power to the load. After the whole vehicle system starts normally, disconnect the shielding power failure protector circuit to make the power failure protector take effect again. As Figure 2 shown.

[0004] The above process cannot be completed automatically and requires manual disconnection of the shielding power failure protector circuit. If the shielding power failure protector circuit is not disconnected after restarting the system, the power failure protector will not work properly, so the protection function cannot be realized. When the locomotive is parked for a long time again, it will cause over-discharge of the battery.

[0005] After the battery enters the power failure state, the current solution is to remove the battery and charge it with an external power supply or replace it with a new battery, which is a great waste of manpower and financial resources.

[0006] Therefore, an automatic and low-cost way is needed to solve the problem of emergency power-on of the power failure protector. Summary of the Utility Model

[0007] Aiming at the problem that the power failure protector of a new energy locomotive cannot reset itself, the utility model provides a power failure protection circuit with an emergency power-on function.

[0008] A power failure protection circuit with an emergency power-on function of the utility model includes a momentary push button, a resistor voltage division circuit, a capacitor charge and discharge circuit, a voltage comparator and a magnetic latching relay.

[0009] Under the normal working state of the 24V battery:

[0010] The 24V battery is connected to the load through the default conduction pin of the magnetic latching relay;

[0011] The 24V battery is also connected to the power loss control coil of the magnetic latching relay through a resistor voltage division circuit, a capacitor charge and discharge circuit, and a voltage comparator; the low-level output signal of the voltage comparator controls the conduction of the power loss control coil of the magnetic latching relay, and the default conduction pin is disconnected, so that the 24V battery is disconnected from the load, and the 24V battery enters the power loss protection state;

[0012] In the power loss protection state of the 24V battery:

[0013] Press the momentary button, the 24V battery charges the capacitor in the capacitor charge and discharge circuit, the high-level output signal of the voltage comparator controls the conduction of the reset control coil of the magnetic latching relay, and at the same time the power loss control coil is disconnected, and the default conduction pin is conducted, so that the 24V battery is connected to the load.

[0014] According to the power loss protection circuit with emergency power-on function of the present invention, configure the discharge time of the capacitor charge and discharge circuit;

[0015] After the momentary button is released, the capacitor in the capacitor charge and discharge circuit discharges through the discharge resistor. During the period when the capacitor voltage reaches the lower limit of the high-level output of the voltage comparator, the locomotive starts, and the 24V battery changes from the power loss protection state to the normal working state.

[0016] According to the power loss protection circuit with emergency power-on function of the present invention, the voltage division coefficient of the resistor voltage division circuit is 5 / 23.

[0017] According to the power loss protection circuit with emergency power-on function of the present invention, the resistor voltage division circuit uses 0805 resistors of 50K and 180K for voltage division.

[0018] According to the power loss protection circuit with emergency power-on function of the present invention, it further includes a voltage follower, and a voltage follower is arranged between the resistor voltage division circuit and the capacitor charge and discharge circuit.

[0019] According to the power loss protection circuit with emergency power-on function of the present invention, the reference voltage of the voltage comparator is 5V. When the voltage of the 24V battery is greater than or equal to 23V, the voltage comparator outputs a high-level output signal; when the voltage of the 24V battery is less than 23V, the voltage comparator outputs a low-level output signal.

[0020] According to the power loss protection circuit with emergency power-on function of the present invention, the model of the voltage comparator is LM2903DR.

[0021] For the power-loss protection circuit with emergency power-on function according to the present utility model, the capacitor in the capacitor charge and discharge circuit is configured such that the voltage discharges from 23V to 5V for 2,200 seconds.

[0022] For the power-loss protection circuit with emergency power-on function according to the present utility model, the capacitor is an electrolytic capacitor with a capacitance value of 220 μF.

[0023] For the power-loss protection circuit with emergency power-on function according to the present utility model, the model of the magnetic latching relay is DS2E-SL2-DC24V.

[0024] Advantages of the present utility model: Based on the RC discharge principle, after the storage battery enters the power-loss protection state, through the control of the momentary switch, the capacitor charge and discharge circuit is temporarily charged to realize the connection between the load and the storage battery, and the vehicle is started. After the vehicle is started, the storage battery in the power-loss state can be replenished with electric energy through the high-voltage power battery.

[0025] The present utility model realizes the power-loss protection of the storage battery through the cooperation of the voltage division circuit, the capacitor charge and discharge circuit, the voltage comparator and the magnetic latching relay; on this basis, through the setting of the momentary button, the temporary power supply to the load is realized in the power-loss protection state of the storage battery, so that the vehicle can be started normally. Thus, the present utility model not only realizes the power-loss protection of the storage battery, but also can realize the power-on start of the system in the power-loss state. It has the advantages of simple operation, low cost, high efficiency, etc., and reduces the power-loss protection cost. Description of the Drawings

[0026] Figure 1 is a schematic diagram of the use of the existing power-loss protector;

[0027] Figure 2 is a schematic diagram of the re-power-on of the existing power-loss protector;

[0028] Figure 3 is a schematic diagram of the principle of the power-loss protection circuit with emergency power-on function according to the present utility model;

[0029] Figure 4 is a block diagram of the structure of the power-loss protection circuit with emergency power-on function according to the present utility model. Detailed Embodiments

[0030] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present utility model.

[0031] It should be noted that, without conflict, the embodiments in the present utility model and the features in the embodiments can be combined with each other.

[0032] The present utility model will be further described below in conjunction with the accompanying drawings and specific embodiments, but it is not limited to the present utility model.

[0033] Specific embodiments: In combination with Figure 3 and Figure 4 as shown, the present utility model provides a power loss protection circuit with an emergency power-on function, including a momentary button 1, a resistor voltage division circuit 2, a capacitor charge and discharge circuit 3, a voltage comparator 4, and a magnetic latching relay 5.

[0034] Under the normal working state of the 24V battery:

[0035] The 24V battery is connected to the load through the default conduction pin of the magnetic latching relay 5.

[0036] The 24V battery is also connected to the power loss control coil of the magnetic latching relay 5 through the resistor voltage division circuit 2, the capacitor charge and discharge circuit 3, and the voltage comparator 4; the low-level output signal of the voltage comparator 4 controls the conduction of the power loss control coil of the magnetic latching relay 5, and the default conduction pin is disconnected, so that the 24V battery is disconnected from the load, and the 24V battery enters the power loss protection state.

[0037] Under the power loss protection state of the 24V battery:

[0038] Press the momentary button 1, the 24V battery charges the capacitor in the capacitor charge and discharge circuit 3, the high-level output signal of the voltage comparator 4 controls the conduction of the reset control coil of the magnetic latching relay 5, and at the same time the power loss control coil is disconnected, and the default conduction pin is conducted, so that the 24V battery is connected to the load.

[0039] The power loss protection circuit described in this embodiment has an emergency power-on function, and it can temporarily power on the load without shielding the power loss protection.

[0040] Furthermore, in combination with Figure 3 and Figure 4 as shown, configure the discharge time of the capacitor charge and discharge circuit 3;

[0041] After the momentary button 1 is released, the capacitor in the capacitor charge and discharge circuit 3 discharges through the discharge resistor. During the period when the capacitor voltage reaches the lower limit of the high-level output of the voltage comparator 4, the locomotive starts, and the 24V battery changes from the power loss protection state to the normal working state.

[0042] During the period when the momentary button 1 is pressed until the capacitor voltage reaches the lower limit at which the voltage comparator 4 outputs a high level, it is equivalent to temporarily powering on the load under the condition of a discharged 24V battery, so that the load can operate normally and start the locomotive to enter the normal driving state. At this time, the high-voltage power battery can charge the battery. If the locomotive is not started when the capacitor voltage discharges to make the voltage comparator 4 output a low level, it will enter the power failure protection state again and cut off the connection between the battery and the load.

[0043] This embodiment uses the RC discharge principle and can realize the power failure protection and temporary power-on functions without a microcontroller and software control, with low cost and extremely low power consumption.

[0044] As an example, the voltage division coefficient of the resistor voltage division circuit 2 is 5 / 23.

[0045] As an example, the resistor voltage division circuit 2 uses 0805 resistors of 50K and 180K for voltage division to meet the power requirement.

[0046] Combined with Figure 4 As shown, this embodiment further includes a voltage follower 6, and a voltage follower 6 is arranged between the resistor voltage division circuit 2 and the capacitor charge and discharge circuit 3. The model of the voltage follower 6 can be LM258DR.

[0047] As an example, the reference voltage of the voltage comparator 4 is 5V. When the 24V battery voltage is greater than or equal to 23V, the voltage comparator 4 outputs a high-level output signal; when the 24V battery voltage is less than 23V, the voltage comparator 4 outputs a low-level output signal.

[0048] As an example, the model of the voltage comparator 4 is LM2903DR.

[0049] Through the voltage comparator 4, the size of the battery voltage is judged. The battery voltage is compared with the negative input of the voltage comparator after voltage division, and a 5V voltage is input to the negative terminal by the voltage reference chip. When the voltage after voltage division is lower than 5V, the comparator outputs a low level; when the voltage after voltage division reaches 5V, the comparator outputs a high level.

[0050] When the comparator outputs a high level, the control coil pins 1-16 of the relay are disconnected, and at the same time, the coil pins 2-15 are conducted. The knife heads 4-6 and 13-11 of the relay are conducted.

[0051] As an example, the capacitor in the capacitor charge and discharge circuit 3 is configured such that the voltage discharges from 23V to 5V for 2200 seconds.

[0052] The duration of the capacitor's discharge from 23V to 5V corresponds to the vehicle start time of the locomotive. If the locomotive is started within the discharge duration, the locomotive can enter the normal use state. If the vehicle is not started within the discharge duration, the voltage comparator will output a low level, and the 24V battery will enter the low-power protection state again. After the low-power protection takes effect again, the load will be cut off again.

[0053] In this implementation manner, the capacitor is an electrolytic capacitor with a capacitance of 220 μF.

[0054] As an example, the model of the magnetic latching relay 5 is DS2E-SL2-DC24V.

[0055] The functions implemented in this embodiment include power-off function and power-on function. Take DS2E-SL2-DC24V as an example: when the 24V battery is connected to the load, the voltage is divided into 5 / 23V by the resistor voltage divider circuit 2, and compared with the 5V reference voltage input by the voltage reference chip at the negative pole of the voltage comparator 4; if the battery voltage reaches 23V, it will reach 5V after voltage division. At this time, the load is normally connected to the battery and is in normal working state. If the battery voltage is lower than 23V, that is, lower than 5V after voltage division, the voltage comparator 4 will output a low level. At this time, the power-loss control coil of the magnetic holding relay 5 is turned on, that is, Figure 3 The 1st and 16th pins of the control coil are turned on. When the 24V battery is in normal working condition, the default conduction switch corresponding to the magnetic latching relay 5 is Figure 3 As shown in the figure, the blades 4-6 and 13-11 are turned on; when the pins 1 and 16 of the control coil are turned on, the blades 4-8 and 13-9 of the magnetic latching relay 5 are connected to the suspended pins, and the load is disconnected from the battery.

[0056] After the 24V battery enters the low-power protection state, press the inching button 1 to charge the 220μF capacitor. At this time, the corresponding reset control coil Figure 3 The middle relay coil 2-15 is turned on. Since the voltage of the capacitor reaches 5V after charging, the comparator outputs a high level, the relay coil 1-16 is disconnected, the relay blades 4-6, 13-11 are connected, the load and the battery are turned on, and after the inching button 1 is released, the capacitor will slowly discharge through the discharge resistor. The capacitor will discharge from 23V to 5V for about 2200 seconds. If high voltage is connected within 2200 seconds, the DCDC module of the locomotive will charge the battery, the battery voltage will increase, and the power-deficient state will be released. If high voltage is not applied during the discharge time, after the capacitor is discharged to below 5V, the comparator will output a low level again, the control coil pins 1 and 16 of the relay will be turned on, and the load will be disconnected.

[0057] Although the present utility model has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present utility model. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed, as long as they do not depart from the spirit and scope of the present utility model as defined by the appended claims. It should be understood that the different dependent claims and the features described herein can be combined in a manner different from that described in the original claims. It should also be understood that the features described in connection with a single embodiment can be used in other described embodiments.

Claims

1. A power-loss protection circuit with an emergency power-on function, characterized in that, It includes a momentary button (1), a resistive voltage division circuit (2), a capacitor charge and discharge circuit (3), a voltage comparator (4), and a magnetic latching relay (5). Under the normal operating state of the 24V battery: The 24V battery is connected to the load through the default conduction pin of the magnetic latching relay (5). The 24V battery is simultaneously connected to the dead battery control coil of the magnetic latching relay (5) through the resistive voltage division circuit (2), the capacitor charge and discharge circuit (3), and the voltage comparator (4); the low-level output signal of the voltage comparator (4) controls the conduction of the dead battery control coil of the magnetic latching relay (5), and the default conduction pin is disconnected, so that the 24V battery is disconnected from the load, and the 24V battery enters the dead battery protection state. Under the dead battery protection state of the 24V battery: Press the momentary button (1), the 24V battery charges the capacitor in the capacitor charge and discharge circuit (3), the high-level output signal of the voltage comparator (4) controls the conduction of the reset control coil of the magnetic latching relay (5), and at the same time the dead battery control coil is disconnected, and the default conduction pin is conducted, so that the 24V battery is connected to the load.

2. The dead battery protection circuit with an emergency power-on function according to claim 1, characterized in that Configure the discharge time of the capacitor charge and discharge circuit (3). After the momentary button (1) is released, the capacitor in the capacitor charge and discharge circuit (3) discharges through the discharge resistor. During the period when the capacitor voltage reaches the lower limit of the high-level output of the voltage comparator (4), the locomotive starts, and the 24V battery changes from the dead battery protection state to the normal operating state.

3. The dead battery protection circuit with an emergency power-on function according to claim 1 or 2, characterized in that The voltage division coefficient of the resistive voltage division circuit (2) is 5 / 23.

4. The dead battery protection circuit with an emergency power-on function according to claim 3, characterized in that The resistive voltage division circuit (2) uses 0805 resistors of 50K and 180K for voltage division.

5. The dead battery protection circuit with an emergency power-on function according to claim 1 or 2, characterized in that It further includes a voltage follower (6), and a voltage follower (6) is provided between the resistive voltage division circuit (2) and the capacitor charge and discharge circuit (3).

6. The dead battery protection circuit with an emergency power-on function according to claim 3, characterized in that The reference voltage of the voltage comparator (4) is 5V. When the voltage of the 24V battery is greater than or equal to 23V, the voltage comparator (4) outputs a high-level output signal; when the voltage of the 24V battery is less than 23V, the voltage comparator (4) outputs a low-level output signal.

7. The dead battery protection circuit with an emergency power-on function according to claim 1, characterized in that The model of the voltage comparator (4) is LM2903DR.

8. The dead battery protection circuit with an emergency power-on function according to claim 2, characterized in that The capacitor in the capacitor charge and discharge circuit (3) is configured such that the voltage discharges from 23V to 5V for 2200 seconds.

9. The dead battery protection circuit with an emergency power-on function according to claim 8, characterized in that The capacitor is an electrolytic capacitor with a capacitance value of 220μF.

10. The power-loss protection circuit with emergency power-on function according to claim 1, characterized in that the model of the magnetic latching relay (5) is DS2E-SL2-DC24V.

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