Self-generating water meter power supply management system and management method

Abstract

The present invention provides a self-generating water meter power management system and management method. The self-generating water meter power management system comprises a lithium ion capacitor or a sodium ion capacitor and a button battery or a dry battery. When the voltage of the lithium ion capacitor or the sodium ion capacitor is lower than a specific protection voltage, the button battery or the dry battery charges the lithium ion capacitor or the sodium ion capacitor to prevent the lithium ion capacitor or the sodium ion capacitor from over-discharging.

Description

Technical Field

[0001] The present invention relates to the field of smart water meters, and in particular to a power supply management system and management method for self-generating smart water meters. Background Art

[0002] Smart water meters have the advantages of being able to electronically display counts and conveniently read readings. Smart water meters read the flow measured by traditional mechanical water meters and then remotely transmit the corresponding readings to the terminal, thereby realizing intelligent remote meter reading. Traditional smart water meters are powered by built-in batteries. Since the battery has limited power, it needs to be replaced regularly.

[0003] Usually, the service life of the battery is 5 years. In actual applications, in order to ensure the accuracy of meter reading, the battery is replaced manually regularly instead of waiting for it to be exhausted. Therefore, the existing ordinary smart water meters need to replace the battery once every five years. Every time the battery is replaced, special personnel need to be arranged to replace it, which increases the double cost of batteries and manpower. In addition, during the period when the smart water meter is powered off and then restarted, the data is prone to errors. In particular, the replaced batteries are a great pollution to the environment.

[0004] In response to this, self-generating water meters came into being. Self-generating water meters use the kinetic energy of water flow in water pipes to generate electricity. The charging and discharging energy storage device stores the electricity and provides electricity to the water meter reading signal transmitter to maintain the normal use of the water meter reading transmitter. However, self-generating water meters have not been successfully used commercially, mainly due to the following problems.

[0005] If lithium batteries are used as charging and discharging energy storage devices, the service life of lithium batteries is too short. After experiments, the number of times lithium batteries can be charged and discharged is only about 1,000 times. If put into practical application, the life of the water meter may even be less than one year in special cases where users use water frequently, intermittently, and in large quantities. In addition, the problem of overcharging or over-discharging of lithium batteries cannot be solved. In any area, it is inevitable that some houses are vacant and no one uses water, so the generator will not be able to charge the lithium battery. If the lithium battery is not charged for a long time, it will age and be destroyed in less than two years. The damaged lithium battery will not be able to be charged and discharged again. Overcharging and over-discharging will cause irreversible damage to the performance and life of the lithium battery. Therefore, if the self-generating water meter using lithium batteries as energy storage devices is not used for a long time, the service life is at most two years, which is much lower than the service life of the existing ordinary smart water meters. Therefore, the self-generating water meter using lithium batteries as energy storage devices has been in the theoretical stage and has not yet been successfully promoted and used commercially.

[0006] In order to avoid the problem of over-discharge causing damage to the energy storage device, some self-generating water meters consider using supercapacitors to store electrical energy. Supercapacitors have the advantages of fast charging speed, high energy utilization, long cycle life, and high safety factor. Most importantly, compared with lithium batteries, overcharging and over-discharging will not have a negative impact on the life of supercapacitors. However, the cost of supercapacitors will be much higher than that of lithium batteries. In addition, compared with traditional ordinary smart water meters, the cost of self-generating water meters using supercapacitors is much higher after adding generators and supercapacitors and other structures on the original basis. In commercial promotion, cost is a very important consideration, which has become a major constraint for the commercial promotion and application of self-generating water meters using supercapacitors. In particular, many people ignore the problem of self-discharge of supercapacitors. Although over-discharge will not affect the life of supercapacitors, the self-discharge rate of supercapacitors is faster than that of lithium batteries. In actual use, if the homeowner is very water-saving and uses a small amount of water each time, the charge will not be enough for the self-discharge of the supercapacitor, and the smart water meter will not be able to send data. Summary of the invention

[0007] In order to overcome at least one shortcoming in the prior art, the present invention provides a self-generating water meter power supply management system and management method.

[0008] In order to achieve one purpose of the present invention, in a first aspect, the present invention provides a self-generating water meter power management system, including a lithium ion capacitor or a sodium ion capacitor and a button battery or a dry battery. When the voltage of the lithium ion capacitor or the sodium ion capacitor is lower than a specific protection voltage, the button battery or the dry battery charges the lithium ion capacitor or the sodium ion capacitor to prevent the lithium ion capacitor or the sodium ion capacitor from over-discharging.

[0009] In one embodiment of the first aspect, the self-generating water meter power management system further includes a diode, the anode of the diode is electrically connected to a button battery or a dry battery, and the cathode of the diode is electrically connected to a lithium ion capacitor or a sodium ion capacitor.

[0010] In an embodiment of the first aspect, the self-generating water meter power management system further includes a resistor connected in series with the diode.

[0011] In one embodiment of the first aspect, the self-generating water meter power management system also includes a detection circuit and a charging circuit. The detection circuit detects the voltage value of the lithium ion capacitor or the sodium ion capacitor and sends a signal to the charging circuit. When the detection circuit detects that the voltage value of the lithium ion capacitor or the sodium ion capacitor is lower than the lower limit of the charging voltage threshold, the charging circuit charges the lithium ion capacitor or the sodium ion capacitor; when the detection circuit detects that the voltage value of the lithium ion capacitor or the sodium ion capacitor is higher than the upper limit of the charging voltage threshold, the charging circuit cuts off the charging of the lithium ion capacitor or the sodium ion capacitor.

[0012] In an embodiment of the first aspect, the self-generating water meter power management system further includes a self-generating power supply and a rectifier and filter circuit, and the power sent by the self-generating power supply is transmitted to the charging circuit after passing through the rectifier and filter circuit.

[0013] In one embodiment of the first aspect, the self-generating water meter power management system also includes a battery protection circuit. When the voltage value of the lithium ion capacitor or the sodium ion capacitor is lower than the lower limit of the discharge voltage threshold, the battery protection circuit cuts off the discharge path of the lithium ion capacitor or the sodium ion capacitor. When the voltage value of the lithium ion capacitor or the sodium ion capacitor is higher than the upper limit of the discharge voltage threshold, the battery protection circuit turns on the discharge path of the lithium ion capacitor or the sodium ion capacitor.

[0014] In an embodiment of the first aspect, the battery protection circuit is electrically connected between the charging circuit and the lithium ion capacitor or the sodium ion capacitor.

[0015] In one embodiment of the first aspect, the self-generating water meter power management system also includes a signal sending circuit. When the voltage value of the lithium ion capacitor or the sodium ion capacitor is lower than the lower limit of the discharge voltage threshold, the battery protection circuit cuts off the electrical connection between the lithium ion capacitor or the sodium ion capacitor and the signal sending circuit to reduce the discharge of the lithium ion capacitor or the sodium ion capacitor; when the voltage value of the lithium ion capacitor or the sodium ion capacitor is higher than the upper limit of the discharge voltage threshold, the battery protection circuit turns on the electrical connection between the lithium ion capacitor or the sodium ion capacitor and the signal sending circuit to allow the lithium ion capacitor or the sodium ion capacitor to provide power to the signal sending circuit.

[0016] In an embodiment of the first aspect, the self-generating water meter power management system further includes a step-down circuit, and a portion of the power transmitted by the lithium ion capacitor or the sodium ion capacitor through the battery protection circuit is supplied to the detection circuit through the step-down circuit.

[0017] In a second aspect, the present invention also provides a power management method for a self-generating water meter power management system, comprising the following steps: when the detection circuit detects that the voltage value of the lithium ion capacitor or the sodium ion capacitor is lower than the lower limit of the charging voltage threshold, the charging circuit charges the lithium ion capacitor or the sodium ion capacitor; when the detection circuit detects that the voltage value of the lithium ion capacitor or the sodium ion capacitor is higher than the upper limit of the charging voltage threshold, the charging circuit cuts off the charging of the lithium ion capacitor or the sodium ion capacitor; when the voltage value of the lithium ion capacitor or the sodium ion capacitor is lower than the lower limit of the discharge voltage threshold, the battery protection circuit cuts off the discharge path of the lithium ion capacitor or the sodium ion capacitor, and when the voltage value of the lithium ion capacitor or the sodium ion capacitor is higher than the upper limit of the discharge voltage threshold, the battery protection circuit turns on the discharge path of the lithium ion capacitor or the sodium ion capacitor; when the voltage of the lithium ion capacitor or the sodium ion capacitor is lower than a specific protection voltage, a button battery or a dry battery charges the lithium ion capacitor or the sodium ion capacitor to prevent over-discharge of the lithium ion capacitor or the sodium ion capacitor.

[0018] In a third aspect, the present invention also provides a self-generating water meter power management system, comprising: an energy storage element; a backup battery, when the voltage of the energy storage element is lower than a specific protection voltage, the backup battery charges the energy storage element to prevent the energy storage element from over-discharging.

[0019] In one embodiment of the third aspect, the energy storage element is a lithium ion capacitor or a sodium ion capacitor.

[0020] In one embodiment of the third aspect, the backup battery is a button battery or a dry cell battery.

[0021] In an embodiment of the third aspect, the self-generating water meter power management system further includes a unidirectional conductive element, which is turned on so that the backup battery can supply power to the energy storage element in a unidirectional manner.

[0022] In one embodiment of the third aspect, the self-generating water meter power management system also includes a current limiting element to balance the current flowing from the backup battery to the energy storage element and the self-discharge current of the energy storage element to ensure that the energy storage element is above a safe voltage to prevent it from being damaged by over-discharge.

[0023] In an embodiment of the third aspect, the unidirectional conducting element is a diode, and the current limiting element is a resistor.

[0024] In an embodiment of the third aspect, an anode of the diode is electrically connected to the backup battery, and a cathode of the diode is electrically connected to the energy storage element.

[0025] In one embodiment of the third aspect, the self-generating water meter power management system also includes a detection circuit and a charging circuit. The detection circuit detects the voltage value of the energy storage element and sends a signal to the charging circuit. When the detection circuit detects that the voltage value of the energy storage element is lower than the lower limit of the charging voltage threshold, the charging circuit charges the energy storage element; when the detection circuit detects that the voltage value of the energy storage element is higher than the upper limit of the charging voltage threshold, the charging circuit cuts off the charging of the energy storage element.

[0026] In an embodiment of the third aspect, the self-generating water meter power management system further includes a self-generating power supply and a rectifier and filter circuit, and the power sent by the self-generating power supply is transmitted to the charging circuit after passing through the rectifier and filter circuit.

[0027] In one embodiment of the third aspect, the self-generating water meter power management system also includes a battery protection circuit. When the voltage value of the energy storage element is lower than the lower limit of the discharge voltage threshold, the battery protection circuit cuts off the discharge path of the energy storage element. When the voltage value of the energy storage element is higher than the upper limit of the discharge voltage threshold, the battery protection circuit turns on the discharge path of the energy storage element.

[0028] In an embodiment of the third aspect, the battery protection circuit is electrically connected between the charging circuit and the energy storage element.

[0029] In one embodiment of the third aspect, the self-generating water meter power management system also includes a signal sending circuit. When the voltage value of the energy storage element is lower than the lower limit of the discharge voltage threshold, the battery protection circuit cuts off the electrical connection between the energy storage element and the signal sending circuit to reduce the discharge of the energy storage element; when the voltage value of the energy storage element is higher than the upper limit of the discharge voltage threshold, the battery protection circuit turns on the electrical connection between the energy storage element and the signal sending circuit to allow the energy storage element to provide power to the signal sending circuit.

[0030] In an embodiment of the third aspect, the self-generating water meter power management system further includes a step-down circuit, and a portion of the power transmitted by the energy storage element through the battery protection circuit is supplied to the detection circuit through the step-down circuit.

[0031] In a fourth aspect, the present invention further provides a power management method for a self-generating water meter power management system, comprising the following steps: when the detection circuit detects that the voltage value of the energy storage element is lower than the lower limit of the charging voltage threshold, the charging circuit charges the energy storage element; when the detection circuit detects that the voltage value of the energy storage element is higher than the upper limit of the charging voltage threshold, the charging circuit cuts off the charging of the energy storage element; when the voltage value of the energy storage element is lower than the lower limit of the discharge voltage threshold, the battery protection circuit cuts off the discharge path of the energy storage element, and when the voltage value of the energy storage element is higher than the upper limit of the discharge voltage threshold, the battery protection circuit turns on the discharge path of the energy storage element; when the voltage of the energy storage element is lower than a specific protection voltage, the backup battery charges the energy storage element to prevent over-discharge of the energy storage element.

[0032] In summary, the self-generating smart water meter power management system provided by the present invention adopts lithium ion capacitors or sodium ion capacitors as energy storage devices. Compared with lithium batteries, lithium ion capacitors or sodium ion capacitors can be charged and discharged more than 500,000 times and have a long service life. Compared with supercapacitors, lithium ion capacitors or sodium ion capacitors have the advantages of high energy density, higher output voltage, and low self-discharge rate, and the cost of lithium ion capacitors or sodium ion capacitors is much lower than that of supercapacitors. When the lithium ion capacitor or sodium ion capacitor is discharged below a specific value, the button battery or dry battery will charge the lithium ion capacitor or sodium ion capacitor to prevent the lithium ion capacitor or sodium ion capacitor from over-discharging, thereby greatly extending the life of the lithium ion capacitor or sodium ion capacitor, thereby promoting the commercial application and promotion of self-generating water meters.

[0033] In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 FIG. 1 is a block diagram of a power management system for a self-generating smart water meter according to a first embodiment of the present invention.

[0035] Figure 2 FIG. 1 is a block diagram of a power management system for a self-generating smart water meter according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0036] Figure 1 FIG. 1 is a block diagram of a power management system for a self-generating smart water meter according to a first embodiment of the present invention. Figure 1 As shown, the self-generating smart water meter power management system provided by the first embodiment of the present invention includes a self-generating power supply 1, a rectifier and filter circuit 2, a charging circuit 3, a battery protection circuit 4, a lithium ion capacitor or a sodium ion capacitor 5, a button battery or a dry battery 6, a detection circuit 7, a step-down circuit 8 and a signal sending circuit 9.

[0037] In this embodiment, the self-generating power source 1 is a micro-hydraulic generator, which uses the water flowing through the water pipe or water meter to drive the turbine of the generator to rotate, converting kinetic energy into electrical energy to generate electricity. After the self-generating power source 1 generates electricity, it transmits the electricity to the rectifier filter circuit 2, which filters out high-frequency harmonics in the alternating current, converts the alternating current after filtering out the clutter into direct current, and then transmits it to the charging circuit 3.

[0038] When the detection circuit 7 detects that the voltage value of the lithium ion capacitor or the sodium ion capacitor 5 is lower than the lower limit of the charging voltage threshold, the charging circuit 3 charges the lithium ion capacitor or the sodium ion capacitor 5; when the detection circuit 7 detects that the voltage value of the lithium ion capacitor or the sodium ion capacitor 5 is higher than the upper limit of the charging voltage threshold, the charging circuit 3 cuts off the charging of the lithium ion capacitor or the sodium ion capacitor 5. When the detection circuit 7 detects that the voltage value of the lithium ion capacitor or the sodium ion capacitor 5 is higher than or equal to the lower limit of the charging voltage threshold and lower than or equal to the upper limit of the charging voltage threshold, the charging circuit 3 does not change the conduction or disconnection between the lithium ion capacitor or the sodium ion capacitor 5, that is, if the charging circuit 3 and the lithium ion capacitor or the sodium ion capacitor 5 are in a conductive charging state, they will continue to be conductive, and if the charging circuit 3 does not charge the lithium ion capacitor or the sodium ion capacitor 5, it will continue to not charge.

[0039] Specifically, when the detection circuit 7 detects that the voltage value of the lithium ion capacitor or the sodium ion capacitor 5 is lower than the lower limit of the charging voltage threshold, the charging circuit 3 is turned on and electrically connected to the lithium ion capacitor or the sodium ion capacitor 5. At this time, the charging circuit 3 charges the lithium ion capacitor or the sodium ion capacitor 5. If the charge amount of the lithium ion capacitor or the sodium ion capacitor 5 is greater than the discharge amount at this time, the voltage of the lithium ion capacitor or the sodium ion capacitor 5 will rise from low to high. When the voltage rises to a value higher than or equal to the lower limit of the charging voltage threshold, the charging circuit 3 does not operate, that is, the charging circuit 3 and the lithium ion capacitor or the sodium ion capacitor 5 are still in the on state, and the charging circuit 3 continues to charge the lithium ion capacitor or the sodium ion capacitor 5, and the voltage of the lithium ion capacitor or the sodium ion capacitor 5 continues to rise. Until the voltage value of the lithium ion capacitor or the sodium ion capacitor 5 is higher than the upper limit of the charging voltage threshold, the charging circuit 3 disconnects the electrical connection with the lithium ion capacitor or the sodium ion capacitor 5 and cuts off the charging of the lithium ion capacitor or the sodium ion capacitor 5. When the discharge amount of the lithium ion capacitor or the sodium ion capacitor 5 is greater than the charge amount, the voltage of the lithium ion capacitor or the sodium ion capacitor 5 decreases from high to low. Since the charging circuit 3 and the lithium ion capacitor or the sodium ion capacitor 5 are disconnected at the beginning, when the voltage of the lithium ion capacitor or the sodium ion capacitor 5 drops to less than or equal to the upper limit of the charging voltage threshold, the charging circuit 3 still does not charge the lithium ion capacitor or the sodium ion capacitor 5, and the charging circuit 3 will charge the lithium ion capacitor or the sodium ion capacitor 5 until the voltage of the lithium ion capacitor or the sodium ion capacitor 5 drops to less than the lower limit of the charging voltage threshold.

[0040] In this embodiment, the upper limit of the charging voltage threshold is 4.0V, and the lower limit of the charging voltage threshold is 3.2V, but the present invention does not impose any limitation on the specific value of the charging voltage threshold. Through this setting, overcharging of the lithium ion capacitor or the sodium ion capacitor 5 is prevented, the lithium ion capacitor or the sodium ion capacitor is effectively protected, and the service life of the lithium ion capacitor or the sodium ion capacitor is extended.

[0041] When the voltage value of the lithium ion capacitor or the sodium ion capacitor 5 is lower than the lower limit of the discharge voltage threshold, the battery protection circuit 4 cuts off the discharge path of the lithium ion capacitor or the sodium ion capacitor 5. When the voltage value of the lithium ion capacitor or the sodium ion capacitor 5 is higher than the upper limit of the discharge voltage threshold, the battery protection circuit 4 turns on the discharge path of the lithium ion capacitor or the sodium ion capacitor 5. When the voltage value of the lithium ion capacitor or the sodium ion capacitor 5 is higher than or equal to the lower limit of the discharge voltage threshold and lower than or equal to the upper limit of the discharge voltage threshold, the battery protection circuit 4 does not change the conduction or disconnection of the discharge path of the lithium ion capacitor or the sodium ion capacitor 5, that is, if the discharge path of the lithium ion capacitor or the sodium ion capacitor 5 is turned on, the lithium ion capacitor or the sodium ion capacitor 5 will continue to discharge to the outside, and if the discharge path of the lithium ion capacitor or the sodium ion capacitor 5 is cut off, it will continue not to discharge.

[0042] Specifically, when the voltage value of the lithium ion capacitor or the sodium ion capacitor 5 is higher than the upper limit of the discharge voltage threshold, the battery protection circuit 4 turns on the discharge path of the lithium ion capacitor or the sodium ion capacitor 5. If the discharge amount of the lithium ion capacitor or the sodium ion capacitor 5 is greater than the charge amount at this time, the voltage of the lithium ion capacitor or the sodium ion capacitor 5 will drop. When the voltage value of the lithium ion capacitor or the sodium ion capacitor 5 drops to less than or equal to the upper limit of the discharge voltage threshold, the battery protection circuit 4 does not operate, and the lithium ion capacitor or the sodium ion capacitor 5 continues to discharge to the outside until the voltage value of the lithium ion capacitor or the sodium ion capacitor 5 is lower than the lower limit of the discharge voltage threshold. The battery protection circuit 4 will cut off the discharge path of the lithium ion capacitor or the sodium ion capacitor 5. If the discharge amount of the lithium ion capacitor or the sodium ion capacitor 5 is less than the charge amount at this time, the voltage of the lithium ion capacitor or the sodium ion capacitor 5 continues to rise. When the voltage value of the lithium ion capacitor or the sodium ion capacitor 5 rises to a value higher than or equal to the lower limit of the discharge voltage threshold, since the discharge path of the lithium ion capacitor or the sodium ion capacitor 5 was disconnected before, the battery protection circuit 4 does not operate at this time, and the lithium ion capacitor or the sodium ion capacitor 5 will not discharge to the outside, and the voltage of the lithium ion capacitor or the sodium ion capacitor 5 will continue to rise until the voltage value of the lithium ion capacitor or the sodium ion capacitor 5 is higher than the upper limit of the discharge voltage threshold, the battery protection circuit 4 will turn on the discharge path of the lithium ion capacitor or the sodium ion capacitor 5.

[0043] Through this configuration, the lithium ion capacitor or sodium ion capacitor 5 is prevented from being over-discharged, the lithium ion capacitor or sodium ion capacitor is effectively protected, and the service life of the lithium ion capacitor or sodium ion capacitor is extended. In this embodiment, the upper limit of the discharge voltage threshold is 4.0V, and the lower limit of the discharge voltage threshold is 3.0V, but the present invention does not impose any limitation on the specific value of the discharge voltage threshold.

[0044] In this embodiment, the battery protection circuit 4 is an integrated circuit, which itself includes a controller and a sensor for detecting the voltage of the lithium ion capacitor or the sodium ion capacitor 5. However, the present invention does not make any limitation to this. In other embodiments, the detection circuit 7 can transmit a signal of the detected voltage value of the lithium ion capacitor or the sodium ion capacitor 5 to the battery protection circuit 4.

[0045] In this embodiment, the battery protection circuit 4 is electrically connected between the charging circuit 3 and the lithium ion capacitor or the sodium ion capacitor 5. The charging circuit 3 of the present invention is not directly connected to the lithium ion capacitor or the sodium ion capacitor 5, but is connected to the lithium ion capacitor or the sodium ion capacitor 5 through the battery protection circuit 4. Through this configuration, when the voltage of the lithium ion capacitor or the sodium ion capacitor 5 is lower than the lower limit of the discharge voltage threshold, the battery protection circuit 4 cuts off all external connections of the lithium ion capacitor or the sodium ion capacitor 5 (except for the connection with the button battery or the dry battery), ensuring that only the self-discharge caused by the loss of the lithium ion capacitor or the sodium ion capacitor 5 itself remains, and no other circuits continue to obtain power from the lithium ion capacitor or the sodium ion capacitor, thereby reducing the self-discharge amount of the lithium ion capacitor or the sodium ion capacitor and extending the self-discharge time of the lithium ion capacitor or the sodium ion capacitor.

[0046] In this embodiment, when the voltage value of the lithium ion capacitor or sodium ion capacitor 5 is lower than the lower limit of the discharge voltage threshold, the battery protection circuit 4 cuts off the electrical connection between the lithium ion capacitor or sodium ion capacitor 5 and the signal transmission circuit 9 to reduce the discharge of the lithium ion capacitor or sodium ion capacitor 5; when the voltage value of the lithium ion capacitor or sodium ion capacitor 5 is higher than the upper limit of the discharge voltage threshold, the battery protection circuit 4 turns on the electrical connection between the lithium ion capacitor or sodium ion capacitor 5 and the signal transmission circuit 9 to allow the lithium ion capacitor or sodium ion capacitor to provide power to the signal transmission circuit 9. The signal transmission circuit 9 transmits the water meter data remotely, thereby realizing remote meter reading.

[0047] In this embodiment, a portion of the power transmitted by the lithium ion capacitor or sodium ion capacitor 5 through the battery protection circuit 4 is supplied to the detection circuit 7 through the step-down circuit 8. When the battery protection circuit 4 cuts off the external power supply of the lithium ion capacitor or sodium ion capacitor 5, the detection circuit 7 and the step-down circuit will not work due to the lack of power supply source, thereby minimizing the self-consumption of the entire power management system.

[0048] In this embodiment, the button cell or dry cell 6 of the present invention is only connected in series with the lithium ion capacitor or sodium ion capacitor 5, and has no direct electrical connection with other circuits of the self-generating water meter power management system, and has no parallel or series relationship with loads outside the self-generating water meter power management system. Through this arrangement, the button cell or dry cell 6 only needs to maintain the self-discharge power demand of the lithium ion capacitor or sodium ion capacitor, and no excess power is needed to power other circuits or external loads, thereby extending the service life of the button cell or dry cell 6. It is also through this arrangement that there is no need to use a large-capacity battery, and a button cell or dry cell 6 can be used, which greatly reduces the production cost of the self-generating water meter power management system. In particular, because the button cell or dry cell 6 is only connected in series with the lithium ion capacitor or sodium ion capacitor 5, and has no series or parallel relationship with other circuits or external loads, the self-generating water meter power management system does not need to set up an additional switching circuit, simplifies the circuit structure, and reduces production costs.

[0049] In this embodiment, the self-generating water meter power management system also includes a diode, which is electrically connected between the button battery or dry battery 6 and the lithium ion capacitor or sodium ion capacitor 5. Due to the unidirectional conduction characteristics, the diode acts as a switch, thereby conducting or cutting off the electrical connection between the button battery or dry battery 6 and the lithium ion capacitor or sodium ion capacitor 5. The anode of the diode is electrically connected to the button battery or dry battery 6, and the cathode is electrically connected to the lithium ion capacitor or sodium ion capacitor 5, so that the current can only flow from the button battery or dry battery to the lithium ion capacitor or sodium ion capacitor. In this embodiment, the self-generating water meter power management system also includes a resistor, which is connected in series with the diode. The resistor plays a current limiting role, while protecting the diode, it also extends the service life of the button battery. According to the daily fixed current demand of the lithium ion capacitor or sodium ion capacitor (that is, the daily self-discharge amount, such as about 2uA), a resistor of the corresponding resistance value is selected to ensure that the amount of charge that the button battery gives to the lithium ion capacitor or sodium ion capacitor every day is equal to the self-discharge amount of the lithium ion capacitor or sodium ion capacitor. This setting prevents the button battery from charging "excess" electricity to the lithium-ion battery, thereby greatly extending the service life of the button battery.

[0050] In practical applications, if no one uses water for a long time, the lithium ion capacitor or sodium ion capacitor has no charging source and will only self-discharge. Due to the setting of button batteries or dry batteries, the voltage of the lithium ion capacitor or sodium ion capacitor is always maintained at a certain value (for example, 2.0V). In practical applications, when residents use tap water, the self-generating power supply 1 generates electricity to continuously charge the lithium ion capacitor or sodium ion capacitor. At this time, since the voltage of the lithium ion capacitor or sodium ion capacitor is lower than the lower limit of the charging voltage threshold (for example, 3.2V), the charging circuit charges the lithium ion capacitor or sodium ion capacitor normally. And since the upper limit of the discharge voltage threshold (for example, 4.0V) has not been reached, the lithium ion capacitor or sodium ion capacitor does not discharge to the outside under the protection of the charging protection circuit at this time, and continuously stores electrical energy, and the real-time voltage value on the lithium ion capacitor or sodium ion capacitor continues to increase.

[0051] When the voltage value of the lithium ion capacitor or sodium ion capacitor rises to a value greater than the upper limit of the charging voltage threshold (4.0V), the charging circuit stops charging the lithium ion capacitor or sodium ion capacitor. At the same time, since the voltage value of the lithium ion capacitor or sodium ion capacitor is greater than the upper limit of the discharge voltage threshold (4.0V), the lithium ion capacitor or sodium ion capacitor provides power to the signal sending circuit, and the signal sending circuit sends a water meter value signal. Since the lithium ion capacitor or sodium ion capacitor is only discharging and has no charging source at this time, the real-time voltage value begins to decrease. When the lithium ion capacitor or sodium ion capacitor drops below the lower limit of the charging voltage threshold (3.2V), the charging circuit resumes charging the lithium ion capacitor or sodium ion capacitor. At this time, the lithium ion capacitor or sodium ion capacitor is charged and discharged at the same time. If the user's water consumption is large at this time, the charge amount of the lithium ion capacitor or sodium ion capacitor will be greater than the discharge amount. At this time, the real-time voltage value of the lithium ion capacitor or sodium ion capacitor will rise, and the state of the lithium ion capacitor or sodium ion capacitor will repeat the above-mentioned state (charging and discharging -> voltage rise -> stop charging and discharging -> voltage drop -> start charging and discharging -> voltage rise -> cycle).

[0052] If the user does not use much water at this time, the discharge amount of the lithium ion capacitor or sodium ion capacitor will be greater than the charge amount, and the real-time voltage value of the lithium ion capacitor or sodium ion capacitor will continue to decrease. When the lithium ion capacitor or sodium ion capacitor drops below the lower limit of the discharge voltage threshold (3.0V), the lithium ion capacitor or sodium ion capacitor does not discharge to the outside under the protection of the battery protection circuit, and stores the electric energy provided by the self-generated power supply. At this time, the detection circuit 7 and the step-down circuit do not work because there is no power supply source.

[0053] If the user stops using water completely at this time, the lithium ion capacitor or sodium ion capacitor will start to self-discharge from 3.0V. The self-discharge of lithium ion capacitors or sodium ion capacitors is very slow. When there is no charging source for a long time, the voltage of the lithium ion capacitor or sodium ion capacitor drops below a specific protection voltage (the specific protection voltage value is the voltage value of the button battery or dry battery minus the value after the conduction voltage of the diode minus the voltage drop of the resistor). In this embodiment, the voltage of the button battery or dry battery is 3V. The conduction voltage of the diode remains basically unchanged (0.7v for silicon tubes and 0.3v for germanium tubes). There is a very small voltage drop on the resistor (because the current is very small, the voltage drop across the resistor can be almost ignored). In this embodiment, when the voltage value of the lithium ion capacitor or the sodium ion capacitor 5 is lower than 2.3V, the voltage difference between the button battery or the dry battery 6 and the lithium ion capacitor or the sodium ion capacitor 5 will cause the diode to be forward-conducted, and the button battery or the dry battery 6 will supply power to the lithium ion capacitor or the sodium ion capacitor 5, thereby preventing the lithium ion capacitor or the sodium ion capacitor 5 from over-discharging, effectively protecting the lithium ion capacitor or the sodium ion capacitor 5, thereby greatly extending the life of the lithium ion capacitor or the sodium ion capacitor 5.

[0054] Due to the setting of button batteries or dry batteries, the voltage of lithium ion capacitors or sodium ion capacitors is always maintained at a certain value (such as 2.3V). At this time, if someone uses water, the lithium ion capacitor or sodium ion capacitor will repeat the above-mentioned state.

[0055] Generally, the service life of button batteries or dry batteries is at least 5 years, and the service life of lithium ion capacitors or sodium ion capacitors is 2 years without external charging. In extreme cases, the service life of the self-generating water meter using the power management system provided by the present invention is at least 7 years, which is longer than the service life of ordinary smart water meters using traditional batteries. At the same time, button batteries or dry batteries and lithium ion capacitors or sodium ion capacitors are used, which are all low-cost electronic components. For the above reasons, the self-generating water meter provided by the present invention can be truly commercially promoted and used.

[0056] In other embodiments, the self-generating water meter power management system may only have lithium ion capacitors or sodium ion capacitors and button batteries or dry batteries. The self-generating power source may be an external generator, and a diode and a resistor may not be provided between the lithium ion capacitor or sodium ion capacitor and the button battery or dry battery, but a transistor or switch may be used to control the disconnection and conduction.

[0057] In summary, the self-generating smart water meter power management system provided by the present invention adopts lithium ion capacitors or sodium ion capacitors as energy storage devices. Compared with lithium batteries, lithium ion capacitors or sodium ion capacitors can be charged and discharged more than 500,000 times and have a long service life. Compared with supercapacitors, lithium ion capacitors or sodium ion capacitors have the advantages of high energy density, higher output voltage, and low self-discharge rate, and the cost of lithium ion capacitors or sodium ion capacitors is much lower than that of supercapacitors. When the lithium ion capacitor or sodium ion capacitor is discharged below a specific value, the button battery or dry battery will charge the lithium ion capacitor or sodium ion capacitor to prevent the lithium ion capacitor or sodium ion capacitor from over-discharging, thereby greatly extending the life of the lithium ion capacitor or sodium ion capacitor, thereby promoting the commercial application and promotion of self-generating water meters.

[0058] In the present invention, the present invention also provides a power management method for a self-generating water meter power management system, comprising the following steps: when the detection circuit detects that the voltage value of the lithium ion capacitor or the sodium ion capacitor is lower than the lower limit of the charging voltage threshold, the charging circuit charges the lithium ion capacitor or the sodium ion capacitor; when the detection circuit detects that the voltage value of the lithium ion capacitor or the sodium ion capacitor is higher than the upper limit of the charging voltage threshold, the charging circuit cuts off the charging of the lithium ion capacitor or the sodium ion capacitor; when the voltage value of the lithium ion capacitor or the sodium ion capacitor is lower than the lower limit of the discharge voltage threshold, the battery protection circuit cuts off the discharge path of the lithium ion capacitor or the sodium ion capacitor, and when the voltage value of the lithium ion capacitor or the sodium ion capacitor is higher than the upper limit of the discharge voltage threshold, the battery protection circuit conducts the discharge path of the lithium ion capacitor or the sodium ion capacitor; when the voltage of the lithium ion capacitor or the sodium ion capacitor is lower than a specific protection voltage, the button battery or the dry battery charges the lithium ion capacitor or the sodium ion capacitor to prevent the lithium ion capacitor or the sodium ion capacitor from over-discharging. The above three steps have no order of precedence and can be performed simultaneously.

[0059] like Figure 2 As shown, in the second embodiment, the self-generating water meter power management system includes a self-generating power supply 1, a rectifier and filter circuit 2, a charging circuit 3, a battery protection circuit 4, an energy storage element 5', a backup battery 6', a unidirectional conducting element 91, a current limiting element 92, a detection circuit 7, a step-down circuit 8 and a signal sending circuit 9.

[0060] In the second embodiment, the self-generating power supply 1, the rectifier filter circuit 2, the charging circuit 3, the battery protection circuit 4, the energy storage element 5', the backup battery 6', the unidirectional conduction element 91, the current limiting element 92, the detection circuit 7, the step-down circuit 8 and the signal transmission circuit 9 may have the same or similar structures as the corresponding elements in the first embodiment. The energy storage element 5' in the second embodiment may be a lithium ion capacitor or a sodium ion capacitor or other types of capacitors, and the backup battery 6' may be a button battery or a dry cell or other storage battery. The unidirectional conduction element 91 in the second embodiment may be a diode or other components / circuits capable of unidirectional conduction. The current limiting element 92 may be a resistor or other components / circuits capable of balancing the current flowing from the backup battery to the energy storage element and the self-discharge current of the energy storage element to ensure that the energy storage element is above the safe voltage to prevent it from being damaged by over-discharge.

[0061] The specific working principle and power management method of the self-generating water meter power management system in the second embodiment are as shown in the first embodiment, and will not be repeated here.

[0062] Although the present invention has been disclosed as above by the preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make slight changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope of protection required by the claims.

Claims

1. A self-generating water meter power management system, characterized in that: include: Lithium ion capacitors or sodium ion capacitors; A charging circuit, when the voltage value of the lithium ion capacitor or the sodium ion capacitor is lower than the lower limit of the charging voltage threshold, the charging circuit charges the lithium ion capacitor or the sodium ion capacitor; Button cell or dry cell, when the voltage of lithium ion capacitor or sodium ion capacitor is lower than the protection voltage, the button cell or dry cell charges the lithium ion capacitor or sodium ion capacitor to prevent over discharge of the lithium ion capacitor or sodium ion capacitor; A battery protection circuit, when the voltage value of the lithium ion capacitor or the sodium ion capacitor is lower than the lower limit of the discharge voltage threshold, the battery protection circuit cuts off the discharge path of the lithium ion capacitor or the sodium ion capacitor, and when the voltage value of the lithium ion capacitor or the sodium ion capacitor is higher than the upper limit of the discharge voltage threshold, the battery protection circuit turns on the discharge path of the lithium ion capacitor or the sodium ion capacitor.

2. The self-generating water meter power management system according to claim 1, characterized in that: It also includes a diode, wherein the anode of the diode is electrically connected to the button battery or the dry battery, and the cathode of the diode is electrically connected to the lithium ion capacitor or the sodium ion capacitor.

3. The self-generating water meter power management system according to claim 2, characterized in that: A resistor is also included and is connected in series with the diode.

4. The self-generating water meter power management system according to claim 1, characterized in that: It also includes a detection circuit, which detects the voltage value of the lithium ion capacitor or the sodium ion capacitor and sends a signal to the charging circuit. When the detection circuit detects that the voltage value of the lithium ion capacitor or the sodium ion capacitor is lower than the lower limit of the charging voltage threshold, the charging circuit charges the lithium ion capacitor or the sodium ion capacitor; When the detection circuit detects that the voltage value of the lithium ion capacitor or the sodium ion capacitor is higher than the upper limit of the charging voltage threshold, the charging circuit cuts off the charging of the lithium ion capacitor or the sodium ion capacitor.

5. The self-generating water meter power management system according to claim 4, characterized in that: It also includes a self-generated power supply and a rectifier and filter circuit. The power sent by the self-generated power supply is transmitted to the charging circuit after passing through the rectifier and filter circuit.

6. The self-generating water meter power management system according to claim 1, characterized in that: The battery protection circuit is electrically connected between the charging circuit and the lithium ion capacitor or the sodium ion capacitor.

7. The self-generating water meter power management system according to claim 1, characterized in that: It also includes a signal sending circuit, when the voltage value of the lithium ion capacitor or the sodium ion capacitor is lower than the lower limit of the discharge voltage threshold, the battery protection circuit cuts off the electrical connection between the lithium ion capacitor or the sodium ion capacitor and the signal sending circuit to reduce the discharge of the lithium ion capacitor or the sodium ion capacitor; When the voltage value of the lithium ion capacitor or the sodium ion capacitor is higher than the upper discharge voltage threshold, the battery protection circuit conducts the electrical connection between the lithium ion capacitor or the sodium ion capacitor and the signal sending circuit to allow the lithium ion capacitor or the sodium ion capacitor to provide power to the signal sending circuit.

8. The self-generating water meter power management system according to claim 1, characterized in that: A step-down circuit is also included, and part of the power transmitted by the lithium ion capacitor or the sodium ion capacitor through the battery protection circuit is supplied to the detection circuit through the step-down circuit.

9. A method for power management using the self-generating water meter power management system as claimed in claim 1, characterized in that: The steps include: When the detection circuit detects that the voltage value of the lithium ion capacitor or the sodium ion capacitor is lower than the lower limit of the charging voltage threshold, the charging circuit charges the lithium ion capacitor or the sodium ion capacitor; When the detection circuit detects that the voltage value of the lithium ion capacitor or the sodium ion capacitor is higher than the upper limit of the charging voltage threshold, the charging circuit cuts off the charging of the lithium ion capacitor or the sodium ion capacitor; When the voltage value of the lithium ion capacitor or the sodium ion capacitor is lower than the lower limit of the discharge voltage threshold, the battery protection circuit cuts off the discharge path of the lithium ion capacitor or the sodium ion capacitor; when the voltage value of the lithium ion capacitor or the sodium ion capacitor is higher than the upper limit of the discharge voltage threshold, the battery protection circuit turns on the discharge path of the lithium ion capacitor or the sodium ion capacitor; When the voltage of the lithium ion capacitor or the sodium ion capacitor is lower than the protection voltage, the button cell or the dry cell charges the lithium ion capacitor or the sodium ion capacitor to prevent the lithium ion capacitor or the sodium ion capacitor from being over-discharged.

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