Protection circuit and energy storage power supply

Abstract

The utility model provides a protection circuit and an energy storage power supply. Wherein the protection circuit is connected with the main circuit, and the protection circuit comprises an acquisition module, a comparison module, a first switch module and a second switch module; the acquisition module is used for dividing a first voltage input by the first power supply to obtain a first divided voltage, and dividing a discharge voltage when receiving the discharge voltage of the battery to obtain a second divided voltage; the comparison module is used for outputting a first control signal when the second divided voltage is greater than the first divided voltage; the first switch module is used for being cut off when receiving the first control signal; the second switch module is used for being cut off when the first switch module is cut off so as to disconnect a discharge path of the battery to the photovoltaic power supply. According to the protection circuit and the energy storage power supply provided by the embodiment of the invention, the problem of over-discharge of the battery is effectively solved by cutting off the discharge path of the battery to the photovoltaic power supply in time.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of electronic circuit, in particular to a protection circuit and energy storage power supply. BACKGROUND

[0002] Many populations in the world are in the area where the power grid is not covered, and there is a huge demand for off-grid energy storage products. In some areas, there is insufficient power supply or even no facilities, and people rely on DC power supply equipment, but often encounter problems such as unstable power supply and insufficient power supply. In the families in Asia and Africa, the power supply mode of energy storage battery combined with photovoltaic panel has become mainstream, that is, the battery supplies power to the DC device, and the photovoltaic panel charges the battery pack.

[0003] However, most PV photovoltaic panel charging circuits regard the photovoltaic panel as a constant current source, adopt a BUCK circuit for current limiting charging, and do not consider the failure of the photovoltaic panel. Once the photovoltaic panel becomes a resistive load or is short-circuited, the energy storage battery pack will be directly short-circuited, which may cause the internal components of the battery pack to burst, the product to fail, or the PV photovoltaic panel to continuously heat, and further cause fire accidents and other serious accidents, which has a great safety hazard. CONTENT OF THE UTILITY MODEL

[0004] The embodiment of the present application provides a protection circuit and energy storage power supply, which can disconnect the discharge path of the battery to the photovoltaic power supply in time when the battery abnormally discharges, and effectively solves the problem of over-discharge of the battery.

[0005] In a first aspect, the embodiment of the present application provides a protection circuit, which is connected with a main circuit, and the protection circuit comprises: an acquisition module, a comparison module, a first switch module and a second switch module; the acquisition module is connected with the comparison module, a first power supply and a battery in the main circuit; the comparison module is connected with the control end of the first switch module; the first switch module is connected with the control end of the second switch module; the first end of the second switch module is connected with a photovoltaic power supply; the second end of the second switch module is connected with the main circuit; the acquisition module is used for dividing the first voltage input by the first power supply to obtain a first divided voltage, and dividing the discharge voltage of the battery to obtain a second divided voltage when the discharge voltage is received; the comparison module is used for outputting a first control signal when the second divided voltage is greater than the first divided voltage; the first switch module is used for being cut off when the first control signal is received; and the second switch module is used for being cut off when the first switch module is cut off, so as to disconnect the discharge path of the battery to the photovoltaic power supply.

[0006] In some embodiments, the acquisition module comprises a resistor R22, a resistor R23, a resistor R25, and a resistor R27; a first end of the resistor R22 is connected with the first power supply, a second end of the resistor R22 is connected with the resistor R23 and the comparison module respectively, a second end of the resistor R23 is grounded, a first end of the resistor R27 is connected with the main circuit, a second end of the resistor R27 is connected with the resistor R25 and the comparison module respectively, and a second end of the resistor R25 is grounded.

[0007] In some embodiments, the acquisition module further comprises a capacitor C4; the capacitor C4 is connected with the resistor R25 in parallel.

[0008] In some embodiments, the comparison module comprises a comparator U2A; a non-inverting input end of the comparator U2A is connected with the acquisition module, an inverting input end of the comparator U2A is connected with the acquisition module, and an output end of the comparator U2A is connected with a control end of the first switch module.

[0009] In some embodiments, the first switch module comprises a switch tube Q8; a control end of the switch tube Q8 is connected with the comparison module and the second power supply respectively, a first end of the switch tube Q8 is grounded, and a second end of the switch tube Q8 is connected with a control end of the second switch module.

[0010] In some embodiments, the first switch module further comprises a resistor R24; a first end of the resistor R24 is connected with the second power supply, and a second end of the resistor R24 is connected with the control end of the switch tube Q8.

[0011] In some embodiments, the second switch module comprises a switch tube Q9; a control end of the switch tube Q9 is connected with the first switch module, a first end of the switch tube Q9 is connected with the photovoltaic power supply, and a second end of the switch tube Q9 is connected with the main circuit.

[0012] In some embodiments, the protection circuit further comprises a current limiting module; a first end of the current limiting module is connected with the first switch module, and a second end of the current limiting module is connected with the control end of the second switch module; the current limiting module is used for limiting the current input to the control end of the second switch module.

[0013] In some embodiments, the current limiting module comprises a resistor R26; a first end of the resistor R26 is connected with the first switch module, and a second end of the resistor R26 is connected with the control end of the second switch module.

[0014] In the second aspect, the embodiments of the present application provide a storage power supply, which comprises the protection circuit as described above.

[0015] Different from the prior art, the embodiment of the application provides a protection circuit and an energy storage power supply. The protection circuit is connected with a main circuit, and the protection circuit comprises a collection module, a comparison module, a first switch module and a second switch module. The collection module is connected with the comparison module, a first power supply and a battery in the main circuit. The comparison module is connected with a control end of the first switch module. The first switch module is connected with a control end of the second switch module. A first end of the second switch module is connected with a photovoltaic power supply. A second end of the second switch module is connected with the main circuit. The collection module is used for dividing a first voltage input by the first power supply to obtain a first voltage, and dividing a discharge voltage of the battery to obtain a second voltage when the discharge voltage is received. The comparison module is used for outputting a first control signal when the second voltage is greater than the first voltage. The first switch module is used for being cut off when the first control signal is received. The second switch module is used for being cut off when the first switch module is cut off, so as to disconnect a discharge path of the battery to the photovoltaic power supply. The protection circuit and the energy storage power supply in the embodiment of the application can effectively solve the problem of over-discharge of the battery by timely disconnecting the discharge path of the battery to the photovoltaic power supply. In addition, since the over-discharge path of the battery can be timely cut off, the battery is prevented from continuously discharging under unreasonable working conditions, so that the service life of the battery is significantly prolonged. Preventing over-discharge of the battery can avoid system failures that may be caused by excessive consumption of the battery, such as voltage drop, circuit abnormality and the like. BRIEF DESCRIPTION OF DRAWINGS

[0016] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, which are schematic and not intended to be limiting of the embodiments, and in which like reference numerals designate similar items in the figures, in which: the drawings do not limit the proportion.

[0017] Figure 1 is a structural schematic diagram of a protection circuit provided by some embodiments of the application;

[0018] Figure 2 is a structural schematic diagram of a protection circuit provided by some embodiments of the application;

[0019] Figure 3 is a circuit structural schematic diagram of a protection circuit provided by some embodiments of the application. DETAILED DESCRIPTION

[0020] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings for the embodiments of the present application to clearly and detailedly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application.

[0021] The technical features involved in the various embodiments of the present application described below can be combined with each other without conflict.

[0022] When an element is expressed as "connected to" another element, it can be directly connected to the other element or one or more intermediate elements can exist therebetween.

[0023] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be exchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than that illustrated or described herein, and the objects distinguished by "first", "second", etc. are usually a class, not limited to the number of objects, for example, the first object can be one or more.

[0024] Please refer to Figure 1 , Figure 1 is a structural schematic diagram of the protection circuit 100 provided by some embodiments of the present application.

[0025] The embodiments of the present application provide a protection circuit 100, the protection circuit 100 is connected with a main circuit 200, and the protection circuit 100 comprises a collection module 11, a comparison module 12, a first switch module 13 and a second switch module 14.

[0026] The collection module 11 is connected with the comparison module 12, a first power supply 300 and a battery 22 in the main circuit 200 respectively, the comparison module 12 is connected with a control end of the first switch module 13, the first switch module 13 is connected with a control end of the second switch module 14, a first end of the second switch module 14 is connected with a photovoltaic power supply 21, and a second end of the second switch module 14 is connected with the main circuit 200.

[0027] Specifically, the acquisition module 11 is configured to divide the first voltage input by the first power source 300 to obtain a first divided voltage, and divide the discharge voltage of the battery 22 to obtain a second divided voltage when the discharge voltage is received. The comparison module 12 is configured to output a first control signal when the second divided voltage is greater than the first divided voltage. The first switch module 13 is configured to be turned off when the first control signal is received. The second switch module 14 is configured to be turned off when the first switch module 13 is turned off, so as to disconnect the discharge path of the battery 22 to the photovoltaic power source 21.

[0028] The first divided voltage is a voltage obtained by dividing the first voltage input by the first power source 300 by the acquisition module 11. It is a reference voltage used for comparison with the divided voltage (the second divided voltage) of the battery 22, so as to determine whether the battery 22 is in abnormal discharge. By reasonably setting the parameters (for example, the resistance value of the resistor) of the elements in the acquisition module 11, a desired first divided voltage can be obtained. The voltage value is determined in advance according to the requirements of the system and the protection strategy, and it represents a reference level in a normal working state. When the second divided voltage is greater than the first divided voltage, it indicates that there is an abnormal discharge of the battery 22 or a failure of the photovoltaic power source 21, which may damage the circuit.

[0029] The second divided voltage is a voltage obtained by dividing the discharge voltage of the battery 22 by the acquisition module 11. This voltage reflects the actual discharge state of the battery 22, and is a key parameter for determining whether the battery is over-discharged to the photovoltaic power source 21. Similar to the first divided voltage, the acquisition module 11 divides the discharge voltage of the battery 22 by a specific voltage dividing circuit. When the battery 22 is discharged, its voltage will pass through the voltage dividing circuit to generate the second divided voltage. If the battery 22 is normally discharged, the second divided voltage should be less than or equal to the first divided voltage; but if the battery 22 is abnormally discharged, such as reverse discharge to the photovoltaic power source 21, the second divided voltage may rise and exceed the first divided voltage, thereby triggering the protection mechanism.

[0030] The first control signal is a signal outputted by the comparison module 12 when it judges that the second divided voltage is greater than the first divided voltage. It is a control instruction for controlling the on or off state of the first switch module 13. The comparison module 12 is usually a comparator circuit which compares the second divided voltage and the first divided voltage as two input signals. When the second divided voltage is greater than the first divided voltage, the comparator outputs a first control signal (for example, a low-level signal) of a specific level. This signal is sent to the control end of the first switch module 13, and according to the type of the first switch module 13 (such as transistor or field effect transistor, etc.), this control signal will change its on state, thereby further affecting the state of the second switch module 14, to realize the protection function of disconnecting the discharging path of the battery 22 to the photovoltaic power supply 21.

[0031] In the embodiment, the collection module 11 is connected to the first power supply 300 and the battery 22 in the main circuit 200 at the same time. For the first voltage inputted by the first power supply 300, the collection module 11 performs a voltage dividing operation to obtain a first divided voltage. When receiving the discharging voltage of the battery 22, it also performs a voltage dividing operation to obtain a second divided voltage. Then, the comparison module 12 compares the first divided voltage and the second divided voltage. When the second divided voltage is greater than the first divided voltage, the comparison module 12 outputs a first control signal. Then, the first switch module 13 is turned off after receiving the first control signal. The off state of the first switch module 13 further affects the second switch module 14, so that the second switch module 14 is also turned off. The second switch module 14 is connected to the photovoltaic power supply 21 and the main circuit 200, and its off state disconnects the discharging path of the battery 22 to the photovoltaic power supply 21, thereby realizing the protection function.

[0032] In some embodiments, referring to Figure 2 , the protection circuit 100 further comprises a current limiting module 15. The first end of the current limiting module 15 is connected to the first switch module 13, and the second end of the current limiting module 15 is connected to the control end of the second switch module 14.

[0033] Specifically, the current limiting module 15 is used for limiting the current inputted to the control end of the second switch module 14.

[0034] Referring to Figure 3 , Figure 3 is a circuit structure schematic diagram of the protection circuit 100 provided in some embodiments of the present application.

[0035] In some embodiments, the acquisition module 11 comprises a resistor R22, a resistor R23, a resistor R25, and a resistor R27. The first end of the resistor R22 is connected to the first power supply 300, the second end of the resistor R22 is connected to the first end of the resistor R23 and the comparison module 12 respectively, the second end of the resistor R23 is grounded, the first end of the resistor R27 is connected to the main circuit 200, the second end of the resistor R27 is connected to the first end of the resistor R25 and the comparison module 12 respectively, and the second end of the resistor R25 is grounded.

[0036] Specifically, the resistor R22 and the resistor R23 are used to divide the voltage input by the first power supply 300 (i.e., the voltage at the 1V_REF end in the Figure 3 ). The resistor R25 and the resistor R27 are used to divide the discharge voltage (i.e., the voltage at the PV_CHG_N end in the Figure 3 ).

[0037] In some embodiments, the acquisition module 11 further comprises a capacitor C4. The capacitor C4 is connected in parallel with the resistor R25.

[0038] Specifically, the capacitor C4 plays a role of time delay, reduces interference, and avoids misjudgment caused by too sensitive signals at the PV_CHG_N end.

[0039] In some embodiments, the comparison module 12 comprises a comparator U2A. The non-inverting input end of the comparator U2A is connected to the acquisition module 11, the inverting input end of the comparator U2A is connected to the acquisition module 11, and the output end of the comparator U2A is connected to the control end of the first switch module 13.

[0040] Specifically, when the voltage at the inverting input end of the comparator U2A (the second divided voltage) is greater than the voltage at the non-inverting input end of the comparator U2A (the first divided voltage), the comparator U2 outputs a low level (i.e., the first control signal). When the voltage at the inverting input end of the comparator U2A (the second divided voltage) is less than or equal to the voltage at the non-inverting input end of the comparator U2A (the first divided voltage), the comparator U2A outputs a high level (i.e., the second control signal).

[0041] In some embodiments, the first switch module 13 comprises a switch tube Q8. The control end of the switch tube Q8 is connected to the comparison module 12 and the second power supply (i.e., +3V3 in the Figure 3 ) respectively, the first end of the switch tube Q8 is grounded, and the second end of the switch tube Q8 is connected to the control end of the second switch module 14.

[0042] Specifically, when the comparator U2A outputs the first control signal (low level), the switch tube Q8 is cut off. When the comparator U2A outputs the second control signal (high level), the switch tube Q8 is turned on.

[0043] The switch tube Q8 can be an NPN triode or any other suitable switching device, which is not limited herein. If the switch tube Q8 is an NPN triode, the control end of the switch tube Q8 is the base of the NPN triode, the first end of the switch tube Q8 is the emitter of the NPN triode, and the second end of the switch tube Q8 is the collector of the NPN triode.

[0044] In some embodiments, the first switch module 13 further includes a resistor R24. The first end of the resistor R24 is connected with the second power supply, and the second end of the resistor R24 is connected with the control end of the switch tube Q8.

[0045] Specifically, the resistor R24 has a current limiting effect. In the state of the comparator U2A being pulled up (i.e., the second control signal), the second power supply (+3V3) drives the triode Q8 through the resistor R24.

[0046] In some embodiments, the second switch module 14 includes a switch tube Q9. The control end of the switch tube Q9 is connected with the first switch module 13, the first end of the switch tube Q9 is connected with the photovoltaic power supply 21, and the second end of the switch tube Q9 is connected with the main circuit 200.

[0047] Specifically, when the switch tube Q8 is off, the switch tube Q9 is also off. When the switch tube Q8 is on, the switch tube Q9 is also on.

[0048] The switch tube Q9 is a P-MOS tube, the control end of the switch tube Q9 is the gate of the P-MOS tube, the first end of the switch tube Q9 is the drain of the P-MOS tube, and the second end of the switch tube Q9 is the source of the P-MOS tube. The body diode of the switch tube Q9 is placed reversely with the body diode of the switch tube Q1 in the main circuit 200. When the switch tube Q9 is off, the discharge path of the battery 22 to the photovoltaic power supply 21 is disconnected.

[0049] In the embodiment, the switch tube Q8 also has a current amplification effect. Since when the switch tube Q9 is a MOS tube, a large input current is needed due to the large internal Ciss input capacitance at the moment when the switch tube Q9 is turned on, and therefore the current amplification through the switch tube Q8 can ensure the normal opening of the MOS tube Q9.

[0050] In some embodiments, the current limiting module 15 includes a resistor R26. The first end of the resistor R26 is connected with the first switch module 13, and the second end of the resistor R26 is connected with the control end of the second switch module 14.

[0051] Specifically, the resistor R26 has a current limiting effect. Since the switch tube Q8 can amplify current, the resistor R26 is used for current limiting to ensure that the maximum power does not exceed the current limiting of the switch tube Q8.

[0052] The embodiment of the present application provides a protection circuit 100, which comprises a collection module 11, a comparison module 12, a first switch module 13 and a second switch module 14. The collection module 11 is connected to a first power supply 300 and a battery 22 in a main circuit 200. The collection module 11 performs voltage division on a first voltage input by the first power supply 300, and obtains a first divided voltage. When receiving a discharge voltage of the battery 22, the collection module 11 also performs voltage division, and obtains a second divided voltage. Then, the comparison module 12 compares the first divided voltage with the second divided voltage. When the second divided voltage is greater than the first divided voltage, the comparison module 12 outputs a first control signal. Then, the first switch module 13 is cut off after receiving the first control signal. The cut-off state of the first switch module 13 further affects the second switch module 14, so that the second switch module 14 is also cut off. The second switch module 14 is connected to a photovoltaic power supply 21 and the main circuit 200, and the cut-off of the second switch module 14 disconnects a discharge path of the battery 22 to the photovoltaic power supply 21, so that the protection function is realized.

[0053] In a circuit comprising a photovoltaic power supply and a battery, once the photovoltaic power supply (usually a photovoltaic panel) fails and becomes a resistive load or is directly short-circuited, the battery is directly short-circuited, that is, the battery is reversely discharged to the photovoltaic power supply. If the reverse discharge is not controlled, the battery is over-discharged, the service life of the battery is shortened, and even the battery is damaged. The protection circuit 100 effectively solves the problem of over-discharge of the battery by timely disconnecting the discharge path of the battery to the photovoltaic power supply. Moreover, since the over-discharge path of the battery can be timely cut off, the battery is prevented from continuously discharging under unreasonable working conditions, so that the service life of the battery is significantly prolonged. Preventing over-discharge of the battery can avoid system failures that may be caused by excessive consumption of the battery, such as voltage drop, abnormal circuit and the like.

[0054] In a second aspect, the embodiment of the present application provides an energy storage power supply, which comprises the protection circuit 100 as described above. The protection circuit 100 is connected to the main circuit 200.

[0055] Specifically, as shown in FIG. 2, Figure 3 The main circuit 200 can comprise a switch tube Q1, an inductor LD1, a freewheeling diode DS22, a resistor R49, a resistor R50, a resistor R29, a resistor ST1, a resistor ST2, a capacitor CE6, a capacitor CE5, a photovoltaic power supply (not shown in the figure), and a battery (not shown in the figure). The positive electrode of the photovoltaic power supply is connected to the PV+ end in the Figure 3 The negative electrode of the photovoltaic power supply is connected to the PV- end in the Figure 3 The positive electrode of the battery is connected to the B+ end in the Figure 3 The negative electrode of the battery is connected to the B- end in the Figure 3 The resistor ST1 and the resistor ST2 are used for current limiting.

[0056] The main circuit 200 takes the PV side (photovoltaic power supply side) as a constant current source input side, and then takes the battery side as an output, and a typical BUCK circuit is built through the switching tube Q1, the inductor LD1 and the freewheeling diode DS22.

[0057] In the embodiment, when the battery has a reverse current, a discharge voltage is generated at the PV_CHG_N. When the reverse current is large, the switching tube Q9 can be closed through the comparator U2A, that is, the reverse current protection can be realized. Meanwhile, the switching tube Q1 can be closed through an external controller, and the reverse current protection can be further completed.

[0058] It should be noted that the specific structure and working principle of the protection circuit 100 can refer to the above embodiment, and will not be described here.

[0059] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; under the idea of the present application, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes of the different aspects of the present application as described above; for the sake of simplicity, they are not provided in the details; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A protection circuit, characterized by, The protection circuit is connected with the main circuit, and the protection circuit comprises a collection module, a comparison module, a first switch module and a second switch module; The collection module is connected with the comparison module, a first power supply and a battery in the main circuit respectively, the comparison module is connected with the control end of the first switch module, the first switch module is connected with the control end of the second switch module, the first end of the second switch module is connected with a photovoltaic power supply, and the second end of the second switch module is connected with the main circuit; The collection module is used for dividing the first voltage input by the first power supply to obtain a first divided voltage and dividing a discharge voltage of the battery to obtain a second divided voltage when the discharge voltage is received; The comparison module is used for outputting a first control signal when the second divided voltage is greater than the first divided voltage; The first switch module is used for being cut off when the first control signal is received; The second switch module is used for being cut off when the first switch module is cut off, so as to disconnect the discharge path of the battery to the photovoltaic power supply.

2. The protection circuit of claim 1, wherein, The collection module comprises resistors R22, R23, R25 and R27; The first end of the resistor R22 is connected with the first power supply, the second end of the resistor R22 is connected with the first end of the resistor R23 and the comparison module respectively, the second end of the resistor R23 is grounded, the first end of the resistor R27 is connected with the main circuit, and the second end of the resistor R27 is connected with the first end of the resistor R25 and the comparison module respectively.

3. The protection circuit of claim 2, wherein, The collection module further comprises a capacitor C4; The capacitor C4 is connected with the resistor R25 in parallel.

4. The protection circuit of claim 1, wherein The comparison module comprises a comparator U2A; The non-inverting input end of the comparator U2A is connected with the collection module, the inverting input end of the comparator U2A is connected with the collection module, and the output end of the comparator U2A is connected with the control end of the first switch module.

5. The protection circuit of claim 1, wherein, The first switch module comprises a switch tube Q8; The control end of the switch tube Q8 is connected with the comparison module and a second power supply respectively, the first end of the switch tube Q8 is grounded, and the second end of the switch tube Q8 is connected with the control end of the second switch module.

6. The protection circuit of claim 5, wherein, The first switch module further comprises a resistor R24; The first end of the resistor R24 is connected with the second power supply, and the second end of the resistor R24 is connected with the control end of the switch tube Q8.

7. The protection circuit of claim 1, wherein, The second switch module comprises a switch tube Q9; The control end of the switch tube Q9 is connected with the first switch module, the first end of the switch tube Q9 is connected with the photovoltaic power supply, and the second end of the switch tube Q9 is connected with the main circuit.

8. The protection circuit according to any one of claims 1 to 7, characterized in that, The protection circuit further comprises a current limiting module; The first end of the current limiting module is connected with the first switch module, and the second end of the current limiting module is connected with the control end of the second switch module; The current limiting module is used for limiting the current input to the control end of the second switch module.

9. The protection circuit of claim 8, wherein, The current limiting module comprises a resistor R26; A first end of the resistor R26 is connected with the first switch module, and a second end of the resistor R26 is connected with a control end of the second switch module.

10. An energy storage power supply, characterized by, The energy storage power supply comprises the protection circuit according to any one of claims 1 to 9.

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