Power switching circuit and power switching system with automatic charging function

Abstract

The utility model provides a power supply switching circuit, which is characterized in that a voltage sampling unit is used for sampling output voltages of two independent power supplies and correspondingly outputting the output voltages to inverted input ends of a first voltage comparison circuit and a second voltage comparison circuit respectively; the in-phase input ends of the first voltage comparison circuit and the second voltage comparison circuit are also connected with a reference voltage, and the reference voltage is used as a threshold judgment reference of power shortage of the power supply; the output of the first voltage comparison circuit / the second voltage comparison circuit is independently connected with the input of one driving circuit, the output of the corresponding driving circuit is connected with the trigger end of the first electric control unit / the second electric control unit, and the switch action end of the first electric control switch / the second electric control switch is used for connecting the output of a power supply and a load; and the input of the OR gate is respectively connected with the outputs of the two independent power supplies. The utility model also provides a power supply switching system with an automatic charging function. According to the utility model, power shortage fluctuation caused by power supply replacement can be reduced, and the circuit is simple and reliable.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of power management, specifically relates to a power switching circuit and power switching system with automatic charging function. BACKGROUND

[0002] With the continuous growth of power demand and the rapid development of new energy technology, power companies are facing the challenges of improving power supply reliability, reducing maintenance costs and meeting diversified energy demand. In the DC power supply system of the substation, and in the power supply of the gas meter, etc. device, there are many scenes that need to apply batteries, but some devices consume more power, and the battery replacement is relatively frequent, not only increases the maintenance workload, but also increases the operating cost, and may cause the key equipment to run interruption, data loss problem, reduces the user experience. Although a standby battery and a switching circuit can be used in the power supply system, there are problems such as single switching mode and instantaneous power failure, therefore, it is necessary to conduct in-depth research. SUMMARY

[0003] In view of the deficiencies in the prior art, the utility model provides a power switching circuit which is equivalent to uninterrupted switching power supply.

[0004] To achieve the above purpose, the utility model adopts the following technical scheme:

[0005] A power switching circuit is used for switching at least two independent power supplies, comprising a voltage sampling unit, a first electric control switch, a second electric control switch, a voltage comparison unit, an or gate and a plurality of drive circuits; the voltage comparison unit comprises a first voltage comparison circuit and a second voltage comparison circuit; the voltage sampling unit is used for sampling the output voltages of the two independent power supplies and is respectively connected to the inverse input terminals of the first voltage comparison circuit and the second voltage comparison circuit; the non-inverting input terminals of the first voltage comparison circuit and the second voltage comparison circuit are also connected to a reference reference voltage, which is used as a threshold value judgment reference for power shortage; the outputs of the first voltage comparison circuit / second voltage comparison circuit are independently connected to the inputs of one of the drive circuits, and the outputs of the corresponding drive circuits are connected to the trigger terminals of the first electric control unit / second electric control unit, and the switching action terminals of the first electric control switch / second electric control switch are used to connect the outputs of the power supply and the load; the inputs of the or gate are respectively connected to the outputs of the two independent power supplies, and the output of the or gate provides power supply for the voltage sampling unit, the voltage comparison unit and the drive circuit; when the first voltage comparison circuit / second voltage comparison circuit outputs high / low, the first electric control switch / second electric control switch is turned off / turned on.

[0006] Further, the two independent power supplies are a first battery unit and a second battery unit.

[0007] Further, the or gate is a diode or gate circuit.

[0008] Further, the reference voltage comprises a power stabilizing module, and the outputs of the first and second battery units are connected to the input of the power stabilizing module through diodes.

[0009] Further, the input of the or gate is also connected to a reference voltage, and the input of the power stabilizing module in the reference voltage comprises a backup power unit; the backup power unit comprises one of an AC-DC conversion power supply circuit, a solar energy conversion power supply circuit and an independent battery.

[0010] Further, the first and second electrically controlled switches are P-channel MOS transistors, the S pole of the first electrically controlled switch P-channel MOS transistor is connected to the positive pole of the first battery unit, the G pole is connected to the output of the driving circuit of the corresponding first voltage comparison circuit, and the D pole is connected to the load; the S pole of the second electrically controlled switch P-channel MOS transistor is connected to the positive pole of the second battery unit, the G pole is connected to the output of the driving circuit of the corresponding second voltage comparison circuit, and the D pole is connected to the load.

[0011] Further, the output of the voltage comparison unit is directly connected or connected through a driving circuit to the trigger end of an alarm module; the alarm module comprises one or several of a sound alarm unit, a light alarm unit and a communication unit.

[0012] The utility model also proposes a power switching system with automatic charging function contains a power switching circuit as described above, first battery unit, second battery unit all are chargeable battery unit, corresponding, still contain solar energy panel, solar energy charging management module, third electrically controlled switch and fourth electrically controlled switch, wherein the output of the solar energy panel is connected to the input of the solar energy charging management module, the output of the solar energy charging management module is connected to the second battery unit and the first battery unit through the switch action end of the third electrically controlled switch and the switch action end of the fourth electrically controlled switch respectively to realize the intercommunication of the charging circuit, the output of the first voltage comparison circuit is connected to the switch trigger end of the fourth electrically controlled switch through a driving circuit, and the output of the second voltage comparison circuit is connected to the switch trigger end of the third electrically controlled switch through a driving circuit.

[0013] The utility model discloses a kind of power supply switching systems with automatic charging function, then combine solar panel and solar charging management system, when realizing the switching of first electric switch and second electric switch, solar charging of power shortage battery is also carried out, so that it can be realized in longer time Maintenance free.Compared with prior art, the judgment and switching speed of the utility model electric switch is faster, can reduce the power replacement caused by power shortage fluctuation, and circuit is simple, not dependent on single-chip microcomputer program control, higher reliability, conducive to promotion. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is the principle diagram for example 1.

[0015] Figure 2 It is the principle diagram for diode or gate. DETAILED DESCRIPTION

[0016] The technical solutions in the utility model are further described below in connection with drawings and examples.

[0017] Example 1

[0018] As Figure 1As shown, the utility model proposes a power switching circuit for switching between at least two independent power supplies, comprising a voltage sampling unit, a first electrically controlled switch, a second electrically controlled switch, a voltage comparison unit, an OR gate, and a plurality of drive circuits; the voltage comparison unit comprises a first voltage comparison circuit and a second voltage comparison circuit; the voltage sampling unit is used to sample the output voltages of the two independent power supplies, and outputs the voltages to the inverting input terminals of the first voltage comparison circuit and the second voltage comparison circuit respectively; in practical applications, the terminal voltages of the first power supply and the second power supply can be sampled by resistor division, or linear optocouplers can be used respectively, with the input terminals of the linear optocouplers connected in series with current limiting resistors to the terminal voltages of the first power supply or the second power supply, and the output of the linear optocouplers is linearly related to the output of the sampled power supply, while avoiding mutual interference between the two independent power supplies. The non-inverting input terminals of the first voltage comparison circuit and the second voltage comparison circuit are further connected to a reference voltage, which is used as a threshold value for determining power failure of the power supply. The output of the first voltage comparison circuit / the second voltage comparison circuit is independently connected to the input of one of the drive circuits, and the output of the corresponding drive circuit is connected to the trigger terminal of the first electronic control unit / the second electronic control unit. The switch action terminal of the first electronically controlled switch / the second electronically controlled switch is used to connect the output of the power supply to the load. It should be noted that a diode is connected between the first electronically controlled switch and the load, and a diode is also connected between the second electronically controlled switch and the load to prevent the direct parallel connection of the two independent power supplies from causing one power supply with different internal resistance and different charge and discharge to form a load for the other (not shown in the figure). drawn, this is the prior art); the inputs of the OR gate are respectively connected to the outputs of two independent power supplies, and the outputs of the OR gate provide power for the voltage sampling unit, the voltage comparison unit, and the drive circuit; through the connection of the OR gate, on the one hand, an independent power supply with sufficient power can be preferentially selected to provide power to the voltage sampling unit, the voltage comparison unit, and the drive circuit to ensure the normal operation of the circuit, and on the other hand, when one of the power supplies is short of power first, double isolation can be achieved through the first electronically controlled switch / the second electronically controlled switch and the diode to avoid the short-powered power supply from continuing to consume power as a load, thereby extending the service life of the power supply; when the first voltage comparison circuit / the second voltage comparison circuit outputs a high level / a low level, the first electronically controlled switch / the second electronically controlled switch is correspondingly cut off / on. In this embodiment, the two independent power supplies are the first battery unit and the second battery unit respectively; as Figure 2As shown, the or gate is a diode or gate circuit, including diodes D1, D2 and resistor R, and the power output provides voltage sampling unit and the like circuit power supply; the reference voltage includes a power supply voltage stabilizing module, the outputs of the first battery unit and the second battery unit are connected to the input of the power supply voltage stabilizing module through diodes, and the output of the power supply voltage stabilizing module is the output of the reference voltage, which is connected to the non-inverting input terminal of the first voltage comparison circuit / second voltage comparison circuit. In this embodiment, the power supply voltage stabilizing module can use TL431, and according to the low-voltage parameters of the battery, the reference voltage output can be realized by combining peripheral resistance adaptation.

[0019] As an embodiment, the first control switch and the second control switch are P-channel MOS tubes, the S pole of the first control switch P-channel MOS tube is connected to the positive pole of the first battery unit, the G pole is connected to the output of the corresponding driving circuit of the first voltage comparison circuit, and the D pole is connected to the load; the S pole of the second control switch P-channel MOS tube is connected to the positive pole of the second battery unit, the G pole is connected to the output of the corresponding driving circuit of the second voltage comparison circuit, and the D pole is connected to the load.

[0020] As an embodiment, the alarm module is further included; the output of the voltage comparison unit is directly connected or connected through the driving circuit to the trigger end of the alarm module; the alarm module includes one or several of the sound alarm unit, the light alarm unit and the communication unit.

[0021] As another embodiment, the input of the or gate is also connected to the reference voltage, and correspondingly, the input of the power supply voltage stabilizing module in the reference voltage also includes a backup power supply unit; the backup power supply unit includes one of an AC-DC conversion power supply circuit, a solar conversion power supply circuit and an independent battery. By including the reference voltage in the input of the or gate, the situation that cannot be alarmed when the first power supply and the second power supply are simultaneously disconnected or extremely low can be avoided.

[0022] The embodiment also provides a power switching system with automatic charging function, comprising a power switching circuit as described above, the first battery unit and the second battery unit are chargeable battery units; correspondingly, the power switching system also comprises a solar panel, a solar charging management module, a third electric control switch and a fourth electric control switch; wherein the output of the solar panel is connected with the input of the solar charging management module, the output of the solar charging management module is connected with the second battery unit and the first battery unit through the switch action end of the third electric control switch and the switch action end of the fourth electric control switch respectively, so as to realize the connection of the charging circuit; the output of the first voltage comparison circuit is connected with the switch trigger end of the fourth electric control switch through the driving circuit; the output of the second voltage comparison circuit is connected with the switch trigger end of the third electric control switch through the driving circuit. Thus, the first battery unit and the second battery unit can be charged by the solar panel, and through appropriate power matching design and illumination measurement, the first battery unit / second battery unit can be continuously powered by solar energy, and the influence of battery replacement or power shortage can be reduced.

[0023] The third electric control switch and the fourth electric control switch are double-pole double-throw switches; correspondingly, a second reference voltage is further included, and an output of the reference voltage is connected to a non-inverting input terminal of the second voltage comparison circuit through a diode, and an output voltage of the second reference voltage is higher than that of the reference voltage; one of the third electric control switch is used to connect an output of the solar charging management system to the second battery unit, and the other of the third electric control switch is used to connect the output of the second reference voltage to the non-inverting input terminal of the second comparison circuit; one of the fourth electric control switch is used to connect the output of the solar charging management system to the first battery unit, and the other of the fourth electric control switch is used to connect the output of the second reference voltage to the non-inverting input terminal of the first comparison circuit. The third electric control switch and the fourth electric control switch are relays. When the first voltage comparison circuit / second voltage comparison circuit outputs a high level, not only the first electric control switch / second electric control switch is turned off to cut off the power supply of the first battery unit / second battery unit to the load, but also the first battery unit / second battery unit in power shortage is synchronously switched to the mode of being connected to the solar panel for charging, and according to the characteristic that the full charge voltage is higher than the power shortage threshold, the reference voltage of the first voltage comparison circuit / second voltage comparison circuit is synchronously switched to the second reference voltage by using the double-pole double-throw switch, so that the first battery unit / second battery unit can be charged to more power until the voltage is greater than the second reference voltage, and then the output of the first voltage comparison circuit / second voltage comparison circuit is affected, thereby realizing the power isolation of the first electric control switch / second electric control switch, the charging connection of the third electric control switch and the fourth electric control switch, and the automatic switching of the charging voltage reference and the power shortage voltage reference. The reference voltage and the second reference voltage can also be obtained by power conversion of the first battery unit and the second battery unit, which is prior art and will not be described here.

[0024] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the purpose and scope of the present application, and all of them should be covered in the scope of the claims of the present application.

Claims

1. A power switching circuit for switching use of at least two independent power sources, characterized by: The application relates to a power supply system, which comprises a voltage sampling unit, a first electrically-controlled switch, a second electrically-controlled switch, a voltage comparison unit, an OR gate and a plurality of drive circuits; the voltage comparison unit comprises a first voltage comparison circuit and a second voltage comparison circuit; the voltage sampling unit is used for sampling the output voltages of two independent power supplies and outputs the voltages to the inverse input terminals of the first voltage comparison circuit and the second voltage comparison circuit respectively; the non-inverting input terminals of the first voltage comparison circuit and the second voltage comparison circuit are also connected with a reference voltage, which is used as a threshold value judgment reference for power supply power failure; the outputs of the first voltage comparison circuit / second voltage comparison circuit are independently connected with the input of one of the drive circuits, the output of the corresponding drive circuit is connected with the trigger terminal of the first electrically-controlled unit / second electrically-controlled unit, and the switch action terminal of the first electrically-controlled switch / second electrically-controlled switch is used for connecting the output of the power supply with a load; the inputs of the OR gate are respectively connected with the outputs of the two independent power supplies, and the output of the OR gate provides power supply for the voltage sampling unit, the voltage comparison unit and the drive circuits; when the first voltage comparison circuit / second voltage comparison circuit outputs a high level / low level, the first electrically-controlled switch / second electrically-controlled switch is turned off / conducting.

2. A power switching circuit as claimed in claim 1, characterized in that: The two independent power supplies are a first battery unit and a second battery unit.

3. A power switching circuit as claimed in claim 2, characterized in that: The OR gate is a diode OR gate circuit.

4. A power switching circuit as claimed in claim 3, characterized in that: The reference voltage comprises a power supply voltage stabilizing module, and the outputs of the first battery unit and the second battery unit are respectively connected with the input of the power supply voltage stabilizing module through diodes.

5. A power switching circuit as claimed in claim 4, characterized in that: The input of the OR gate is also connected with a reference voltage, and correspondingly, the input of the power supply voltage stabilizing module in the reference voltage also comprises a backup power supply unit; the backup power supply unit comprises one of an AC-DC conversion power supply circuit, a solar energy conversion power supply circuit and an independent battery.

6. A power switching circuit as claimed in claim 3, characterized in that: The first electrically-controlled switch and the second electrically-controlled switch are P-channel MOS transistors, the S terminal of the first electrically-controlled switch P-channel MOS transistor is connected with the positive pole of the first battery unit, the G terminal is connected with the output of the drive circuit corresponding to the first voltage comparison circuit, and the D terminal is connected with a load; the S terminal of the second electrically-controlled switch P-channel MOS transistor is connected with the positive pole of the second battery unit, the G terminal is connected with the output of the drive circuit corresponding to the second voltage comparison circuit, and the D terminal is connected with a load.

7. A power switching circuit as claimed in claim 1, characterized in that: The application further comprises an alarm module; the output of the voltage comparison unit is directly connected with the trigger terminal of the alarm module or is connected with the trigger terminal of the alarm module through a drive circuit; the alarm module comprises one or several of a sound alarm unit, a light alarm unit and a communication unit.

8. A power switching system with automatic charging function, characterized by: The power switching circuit comprises the first battery unit and the second battery unit, and further comprises a solar panel, a solar charging management module, a third electrically controlled switch and a fourth electrically controlled switch.

9. The power switching system having an automatic charging function according to claim 8, characterized by: The third electrically controlled switch and the fourth electrically controlled switch are double-pole double-throw switches, and the power switching circuit further comprises a second reference voltage, wherein an output of the second reference voltage is connected to a non-inverting input of the second voltage comparison circuit through a diode, and an output voltage of the second reference voltage is higher than an output voltage of the reference voltage.

10. The power switching system having an automatic charging function according to claim 9, characterized by: The third electrically controlled switch and the fourth electrically controlled switch are relays.

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