CN111009950A - Overcharge protection circuit and charger - Google Patents
Overcharge protection circuit and charger Download PDFInfo
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- CN111009950A CN111009950A CN201911416143.XA CN201911416143A CN111009950A CN 111009950 A CN111009950 A CN 111009950A CN 201911416143 A CN201911416143 A CN 201911416143A CN 111009950 A CN111009950 A CN 111009950A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
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- Charge And Discharge Circuits For Batteries Or The Like (AREA)
Abstract
The invention relates to the technical field of protection circuits, and discloses an overcharge protection circuit and a charger, which are applied to a charging loop of a photovoltaic power generation energy storage system, wherein the overcharge protection circuit comprises a sampling circuit, a control circuit and a switch circuit, wherein the sampling circuit is used for sampling the output voltage of the charging loop, and the control circuit is connected with the sampling circuit and is used for generating a control signal according to the output signal of the sampling circuit; and the switch circuit is respectively connected with the control circuit and the charging circuit and is used for controlling the working state of the charging circuit according to the control signal, and the working state comprises a connection state and a disconnection state. Therefore, when the charging circuit is overcharged, the control circuit controls the switch circuit to be in the open circuit working state, so that the charging circuit is disconnected, and the charging circuit is reliably overcharged and protected.
Description
Technical Field
The invention relates to the technical field of protection circuits, in particular to an overcharge protection circuit and a charger.
Background
In the design and manufacture process of the off-grid photovoltaic power generation energy storage system, the overcharge protection circuit is very important, and the safety problem of the energy storage system in the charging process is determined to a great extent. If the overcharge protection circuit fails, the battery pack is very easy to charge and over-voltage occurs when the energy storage system is charged, and then the battery pack is in fire or explosion, which is very dangerous. Therefore, the design of the overcharge protection circuit has a significant effect on the energy storage system.
In an off-grid photovoltaic power generation energy storage system, a voltage detection feedback control method is usually adopted for the design of a charging system, namely, the MCU is used for controlling the charging system by detecting the voltage of a battery, the MCU is used for sampling the voltage of the battery in real time, in the charging process, if the voltage of a battery pack is lower, the MCU is used for controlling the charging system to charge the battery pack in a constant current mode, when the battery pack is to be fully charged, the MCU is used for controlling the charging system to charge the battery pack in a constant voltage mode, and when the voltage of the battery pack is increased to a set charging cut-off voltage value, the MCU is used for turning off the charging system, so that the overcharge phenomenon is. The charging protection strategy is completely realized by software, so when the sampling of the battery is abnormal or the MCU control system fails, the MCU controls the charging system wrongly, and effective overcharge protection is difficult to realize. Therefore, the current overcharge protection operation cannot reliably over-protect the charging system.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide an overcharge protection circuit and a charger, which can realize reliable overcharge protection.
The purpose of the invention is realized by the following technical scheme:
in order to solve the above technical problem, in a first aspect, an embodiment of the present invention provides an overcharge protection circuit applied to a charging loop of a photovoltaic power generation energy storage system, including:
the sampling circuit is used for sampling the output voltage of the charging loop;
the control circuit is connected with the sampling circuit and used for generating a control signal according to the output signal of the sampling circuit; and
and the switch circuit is respectively connected with the control circuit and the charging loop and is used for controlling the working state of the charging loop according to the control signal, and the working state comprises a closed circuit state and an open circuit state.
Optionally, the control circuit includes:
and the comparison circuit is respectively connected with the sampling circuit and the switch circuit and is used for outputting the control signal to control the working state of the switch circuit according to the sampling signal and a preset voltage threshold, and the working state comprises a closed circuit state and an open circuit state.
Optionally, the control circuit further includes:
and the driving circuit is respectively connected with the comparison circuit and the switch circuit and is used for driving the switch circuit.
Optionally, the control circuit further includes:
and the optical coupling isolation circuit is respectively connected with the driving circuit and the switch circuit.
Optionally, the switching circuit includes: the charging circuit comprises a first switch circuit, a second switch circuit and a third switch circuit which are connected in series, wherein the first switch circuit is also connected with the control circuit, and the third switch circuit is also connected with the charging circuit.
Optionally, the sampling circuit includes a first operational amplifier, a non-inverting input terminal of the first operational amplifier is connected to an output voltage anode of the charging loop, an inverting input terminal of the first operational amplifier is connected to an output voltage cathode of the charging loop, and an output terminal of the first operational amplifier is connected to the control circuit.
Optionally, the comparison circuit includes a second operational amplifier, a non-inverting input terminal of the second operational amplifier is connected to the output terminal of the first operational amplifier, and an inverting input terminal of the second operational amplifier is connected to the preset voltage threshold.
Optionally, the driving circuit is a first triode, a base of the first triode is connected with an output end of the second remote computing amplifier, a collector of the first triode is connected with the optocoupler isolation circuit, and an emitter of the first triode is grounded.
Optionally, the first switch circuit is a second triode, the second switch circuit is a third diode, the third switch circuit is an MOS switch tube, the base of the second triode is connected with the optical coupling isolation circuit, the collector of the second triode is connected with the base of the third triode, the emitter of the second triode is grounded together with the emitter of the third triode, and the collector of the third triode is connected with the gate of the MOS switch tube to control the conduction or cut-off of the MOS switch tube.
Optionally, the overcharge protection circuit further includes an auxiliary power supply circuit, and the auxiliary power supply circuit is connected to the sampling circuit and the control circuit, respectively, and is configured to provide a working voltage.
In a second aspect, an embodiment of the present invention provides a charger, including:
the photovoltaic power generation system is used for generating electric energy by adopting the photovoltaic system;
the overcharge protection circuit is connected with the photovoltaic power generation system and used for overcharge protection; and
and the charging loop is respectively connected with the overcharge protection circuit and an external storage battery pack and is used for charging the external storage battery pack with electric energy generated by the photovoltaic power generation system.
Compared with the prior art, the invention has the beneficial effects that: the invention provides an overcharge protection circuit which is applied to a charging loop of a photovoltaic power generation energy storage system and is different from the prior art, wherein the overcharge protection circuit comprises a sampling circuit, a control circuit and a switch circuit, the sampling circuit is used for sampling the output voltage of the charging loop, and the control circuit is connected with the sampling circuit and is used for generating a control signal according to the output signal of the sampling circuit; and the switch circuit is respectively connected with the control circuit and the charging circuit and is used for controlling the working state of the charging circuit according to the control signal, and the working state comprises a connection state and a disconnection state. Therefore, when the charging circuit is overcharged, the control circuit controls the switch circuit to be in the open circuit working state, so that the charging circuit is disconnected, and the charging circuit is reliably overcharged and protected.
Drawings
One or more embodiments are illustrated by the accompanying figures in the drawings that correspond thereto and are not to be construed as limiting the embodiments, wherein elements/modules and steps having the same reference numerals are represented by like elements/modules and steps, unless otherwise specified, and the drawings are not to scale.
Fig. 1 is a schematic structural diagram of a charger according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an overcharge protection circuit according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of an overcharge protection circuit according to another embodiment of the present invention;
fig. 4 is a schematic circuit diagram of an overcharge protection circuit according to yet another embodiment of the present invention.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
Referring to fig. 1, fig. 1 is a diagram illustrating a charger applied to a photovoltaic power generation energy storage system according to an embodiment of the present invention, where the photovoltaic power generation system is a power generation system that directly converts light energy into electric energy without a thermal process. Its main components are solar cell, accumulator, controller and inverter. The device has the characteristics of high reliability, long service life, no environmental pollution, independent power generation and grid-connected operation. The photovoltaic power generation system comprises a storage battery pack and a storage battery controller, wherein the storage battery pack is used for storing electric energy generated when a solar battery matrix is illuminated and supplying power to a load at any time, and the storage battery controller is equipment capable of automatically preventing overcharge and over-discharge of the storage battery. Since the number of cycles of charging and discharging the battery and the depth of discharge are important factors for determining the service life of the battery, a battery controller capable of controlling overcharge or overdischarge of the battery pack is indispensable. Therefore, in a charging circuit of a photovoltaic power generation energy storage system for charging a storage battery, it is necessary to provide an overcharge protection circuit to prevent the storage battery from being overcharged, so that the storage battery is damaged.
As shown in fig. 1, the charger includes a photovoltaic power generation system 400, an overcharge protection circuit 100, and a charging loop 200, wherein the electric energy generated by the photovoltaic power generation system 400 charges the battery pack 300 through the charging loop 200, the battery pack 300 stores the electric energy generated by the photovoltaic power generation system 400, the overcharge protection circuit 100 is disposed between the photovoltaic power generation system 400 and the charging loop 200, the charging loop 200 is respectively connected with the overcharge protection circuit 100 and the battery pack 300, when the battery pack 300 is charged, the overcharge protection circuit 100 is in a closed state, so that the photovoltaic power generation system 400 can normally charge the battery pack 300 through the charging loop 200, if the battery pack 300 has an overcharge phenomenon, and the overcharge protection circuit 100 detects that the charging output voltage reaches an overcharge value, the circuit between the photovoltaic power generation system 400 and the charging loop 200 is disconnected, so that the charger operates in a closed circuit operating state, and then the charger can not charge the storage battery pack 300 any more, so as to achieve the purpose of overcharge protection of the storage battery pack 300.
Referring to fig. 2, fig. 2 is a schematic structural diagram of an overcharge protection circuit according to an embodiment of the present invention, as shown in fig. 2, the overcharge protection circuit 100 includes a sampling circuit 10, a control circuit 20 and a switch circuit 30, the sampling circuit 10 is configured to sample an output voltage of a charging loop 200, and the control circuit 20 is connected to the sampling circuit 10 and configured to generate a control signal according to an output signal of the sampling circuit 10; and the switch circuit 30 is respectively connected with the control circuit 20 and the charging circuit 200, and is used for controlling the working state of the charging circuit 200 according to the control signal, wherein the working state comprises a connection state and a disconnection state. Therefore, when the charging circuit 200 is overcharged, the control circuit 20 controls the switch circuit 30 to be in the open-circuit working state, so that the charging circuit 200 is disconnected, the photovoltaic power generation system 400 cannot charge the storage battery pack 300 any more, and the storage battery pack 300 is reliably protected from overcharge.
Referring to fig. 3, fig. 3 is a schematic diagram of an overcharge protection circuit according to another embodiment of the present invention, as shown in fig. 3, the overcharge protection circuit 100 includes a sampling circuit 10, a control circuit 20 and a switch circuit 30, the sampling circuit 10 is respectively connected to a charging circuit 200 and the control circuit 20, the control circuit 20 is respectively connected to the sampling circuit 10 and the switch circuit 30, the switch circuit 30 is further connected to the charging circuit 200, and a working state of the switch circuit 30 controls a connection and a disconnection of the charging circuit 200.
The control circuit 20 includes a comparison circuit 21, which is respectively connected to the sampling circuit 10 and the switch circuit 30, and configured to output the control signal to control a working state of the switch circuit 30 according to a sampling signal and a preset voltage threshold, where the working state includes an on state and an off state. The sampling signal is the output voltage of the charging circuit 200, the preset voltage threshold is a preset defined voltage value, when the sampling voltage value is greater than the preset voltage threshold, it is indicated that the charged storage battery reaches an overvoltage protection value, the comparison circuit 21 outputs a first control signal, and then the first control signal controls the switch circuit 30 to be switched off, so that the charging circuit 200 works in a circuit-breaking working state, the charging circuit 200 cannot continue to charge the storage battery, and overcharge protection is reliably realized on the storage battery at the rear. In the embodiment of the present invention, the preset voltage threshold may be +5V, but it should be noted that the preset voltage threshold may be set according to the requirement, and is not limited by the embodiment of the present invention.
In some embodiments, with reference to fig. 3, the control circuit 20 further includes a driving circuit 22, and the driving circuit 22 is connected to the comparing circuit 21 and the switching circuit 30, respectively, for driving the switching circuit 30. The comparator 21 outputs a control signal, and acts on the driver 22, and the driver 22 generates a control signal based on the control signal to drive the switch 30 to operate, thereby changing the operating state of the switch 30.
In some embodiments, please continue to refer to fig. 3, the control circuit 20 further includes an optical coupling isolation circuit 23, the optical coupling isolation circuit 23 is respectively connected to the driving circuit 22 and the switching circuit 30, and the switching circuit 30 is further connected to the charging circuit 200, so that the optical coupling isolation circuit 23 reliably isolates the driving signal from the working signal of the charging circuit 200, so that the driving signal is transmitted unidirectionally, and the working signal of the driving circuit 22 and the switching circuit 30 is electrically isolated, and the output signal has no influence on the input end, and has strong anti-interference capability and stable working, so that the driving signal can reliably act on the switching circuit 30, and the working state of the switching circuit 30 is controlled, thereby further improving the working stability and reliability of the overcharge protection circuit.
In some embodiments, please refer to fig. 3, the switch circuit 30 includes a first switch circuit 31, a second switch circuit 32 and a third switch circuit 33 connected in series, the first switch circuit 31 is further connected to the control circuit 20, the third switch circuit 33 is further connected to the charging loop 200, specifically, the first switch circuit 31 is connected to the optical coupler isolation circuit 23 and the second switch circuit 32, respectively, and the third switch circuit 33 is disposed on the charging bus of the charging loop 200. When the storage battery pack is overcharged, the output signal of the optical coupling isolation circuit 23 controls the first switch circuit 31 to be switched on, the second switch circuit 32 works in a circuit-breaking working state due to the switching on of the first switch circuit 31, and then the second switch circuit 32 has no output signal, so that the third switch circuit 33 works in a circuit-breaking working state, and therefore a charging bus of the charging circuit 200 is in a disconnected state, so that the charging circuit 200 is disconnected, the storage battery pack cannot be charged any more, and overcharge protection is reliably realized.
In some embodiments, the overcharge protection circuit 100 further includes an auxiliary power circuit 40, and the auxiliary power circuit 40 is connected to the sampling circuit 10 and the control circuit 20, respectively, for providing an operating voltage. The auxiliary power circuit 40 is used to provide an operating voltage to each circuit in the overcharge protection circuit 100, so that each circuit can operate normally. Generally, the voltage provided by the auxiliary power circuit 40 is a low voltage, which is +5V in the embodiment of the present invention, but it should be noted that the operating voltage of each circuit may be determined by the specific chip included in each circuit, and is not limited to the specific value of the embodiment of the present invention.
Referring to fig. 4, fig. 4 is a schematic circuit diagram of an overcharge protection circuit according to yet another embodiment of the present invention. As shown in fig. 4, the sampling circuit 10 includes a first operational amplifier U1, a non-inverting input terminal of the first operational amplifier U1 is connected to the positive electrode of the output voltage of the charging circuit 200, an inverting input terminal of the first operational amplifier U1 is connected to the negative electrode OUT _ V "of the output voltage of the charging circuit 200, an output terminal of the first operational amplifier U1 is connected to the control circuit 20, specifically, an output terminal of the first operational amplifier U1 is connected to the input terminal of the comparison circuit 21, and in order to filter noise in the output signal of the charging circuit 200, the sampling circuit 10 further includes a first filter capacitor C1 and a second filter capacitor C2, the first filter capacitor C1 is connected to the inverting input terminal of the first operational amplifier U1 and the output terminal of the first operational amplifier, the second filter capacitor C2 is connected to the non-inverting input terminal of the first operational amplifier U1 and ground, here ground is signal ground (AGND).
In some embodiments, please continue to refer to fig. 4, the sampling circuit 10 further includes a first resistor R1, a second resistor R2, and a third resistor R3, wherein the first resistor R1 is connected in series between the negative terminal OUT _ V-of the output terminal of the charging circuit 200 and the inverting input terminal of the first operational amplifier U1, the second resistor R2 is connected in series between the positive terminal OUT _ V + of the output terminal of the charging circuit and the inverting input terminal of the first operational amplifier U1, and the third resistor R3 is connected in series between the inverting input terminal of the first operational amplifier U1 and the output terminal of the first operational amplifier U1, which is a feedback resistor.
In some embodiments, with continued reference to fig. 4, the comparison circuit 21 includes a second operational amplifier U2, the non-inverting input of the second operational amplifier U2 is connected to the output of the first operational amplifier U1, and the inverting input of the second operational amplifier U2 is connected to the predetermined voltage threshold. In the embodiment of the present invention, the preset voltage threshold is + 5V.
In some embodiments, with continued reference to fig. 4, the comparison circuit 21 further includes a third capacitor C3, and the third capacitor C3 is connected in series between the non-inverting input terminal of the second operational amplifier U2 and ground, where ground is signal ground (AGND). The comparison circuit 21 further includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and an eighth resistor R8, the fourth resistor R4 is connected in series between the inverting input terminal of the second operational amplifier U2 and a signal ground (AGND), the fifth resistor R5 is connected in series between the non-inverting input terminal of the second operational amplifier U2 and the output terminal of the first operational amplifier U1, the sixth resistor R6 is connected in series between the inverting input terminal of the second operational amplifier U2 and a +5V power supply, the seventh resistor R7 is connected in series between the output terminal of the second operational amplifier U2 and the +5V power supply, and the eighth resistor R8 is connected in series between the output terminal of the second operational amplifier U2 and the driving circuit 22. The fourth resistor R4 is a pull-down resistor, the fifth resistor R5 and the eighth resistor R8 are both current-limiting resistors, and the sixth resistor R6 and the seventh resistor R7 are both pull-up resistors.
The second operational amplifier U2 outputs a high level signal or a low level signal according to the output signal of the first operational amplifier U1 and a preset voltage threshold, if the output signal of the first operational amplifier U1 is greater than the preset voltage threshold +5V, it is proved that the charged battery pack reaches an overvoltage protection value, the second operational amplifier U2 outputs a high level signal to control the rear-end switch circuit 30 to operate in an open circuit working state, if the output signal of the first operational amplifier U1 is less than the preset voltage threshold +5V, it is proved that the charged battery pack does not reach the overvoltage protection value, the second operational amplifier U2 outputs a low level signal to control the rear-end switch circuit 30 to operate in an open circuit working state, so that the charger loop 200 continues to charge the battery pack.
In some embodiments, referring to fig. 4, the driving circuit 22 is a first transistor Q1, a base of the first transistor Q1 is connected to the output terminal of the second remote amplifier U2, a collector of the first transistor Q1 is connected to the optical coupling isolation circuit 23, and an emitter of the first transistor Q1 is connected to a signal ground (AGND).
In some embodiments, with continued reference to fig. 4, the driving circuit 22 further includes a ninth resistor R9 and a tenth resistor R10, the ninth resistor R9 is connected in series between the base of the first transistor Q1 and the signal ground (AGND), and the tenth resistor R10 is connected in series between the optical coupler isolation circuit 23 and the collector of the first transistor Q1. The output signal of the second operational amplifier U2 may control the first transistor Q1 to turn on or off by controlling the base of the first transistor Q1. The ninth resistor R9 is a pull-down resistor, and the tenth resistor R10 is a current limiting resistor.
In some embodiments, please continue to refer to fig. 4, the optical isolator circuit 23 includes an optical isolator U3, a first terminal of the optical isolator U3 is connected to the +5V power supply, a second terminal of the optical isolator is connected to one end of a tenth resistor, a third terminal of the optical isolator U3 is connected to the Input terminal of the first switch circuit, a fourth terminal of the optical isolator is connected to the positive Input terminal Input + of the charging loop 200 through an eleventh resistor R11, and the eleventh resistor R11 is a current-limiting resistor. If the collector of the first triode Q1 outputs a low voltage signal, the Input terminal of the optocoupler isolator U3 is turned on, and then the output terminal path of the optocoupler isolator U3 is turned on, i.e., the positive Input terminal positive + of the positive Input terminal of the charging loop 200 passes through the eleventh resistor R11, the fourth terminal of the optocoupler isolator U3, the third terminal of the optocoupler isolator U3 and the first switch circuit 31 form a path, and the third terminal outputs a high voltage signal, and then the first switch circuit 31 is driven to be turned on.
In some embodiments, with reference to fig. 4, the first switch circuit 31 is a second transistor Q2, the second switch circuit 32 is a third diode Q3, the third switch circuit 33 is a MOS switch, the base of the second transistor Q2 is connected to the optical coupling isolation circuit 23, the collector of the second transistor Q2 is connected to the base of the third transistor Q3, the emitter of the second transistor Q2 and the emitter of the third transistor Q3 are grounded, and the collector of the third transistor Q3 is connected to the gate of the MOS switch Q4, so as to control the on/off of the MOS switch Q4.
Specifically, the switch circuit 30 further includes a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, and an eighteenth resistor R18. A twelfth resistor R12 is connected in series between the base of the second transistor Q2 and the ground, where the ground is a charging Input ground (ingad), a thirteenth resistor R13 is connected in series between the collector of the second transistor Q2 and the charging Input ground (ingad), a fourteenth resistor R14 is connected in series between the collector of the second transistor Q2 and the positive electrode of the charging Input, a fifteenth resistor R15 is connected in series between the collector of the second transistor Q2 and the base of the third transistor Q3, a sixteenth resistor R16 is connected in series between the collector of the third transistor Q3 and an eighteenth resistor R18, a seventeenth resistor R17 is connected in series between the sixteenth resistor R16 and the positive electrode of the charging Input, an eighteenth resistor R18 is connected in series between the sixteenth resistor R16 and the gate of the MOS switch Q4, the MOS switch Q4 is disposed on the bus of the charging loop 200, the source electrode of the MOS switch tube Q4 is connected with the positive electrode Input + of the charging Input, and the MOS switch tube Q4 is a PMOS switch tube.
Therefore, when the second transistor Q2 is turned on, the voltage at the collector terminal of the second transistor Q2 is pulled low, and a low voltage signal is outputted, and the low voltage signal is applied to the base of the third transistor Q3, so that the third transistor Q3 is turned off, and the gate terminal potential of the MOS switch Q4 is equal to the positive Input + potential of the charging Input terminal, so that the MOS switch Q4 is turned off, and the charging loop is disconnected.
As shown in fig. 4, the medium +5V power of the overcharge protection circuit 100 can be provided by the auxiliary power circuit 40, wherein the auxiliary power circuit 40 includes a fourth transistor Q5, a nineteenth resistor R19, a twentieth resistor R20 and a twenty-first resistor R21, a collector of the fourth transistor Q5 is connected to a non-inverting input terminal of the first operational amplifier U1 through the twenty-first resistor R21, a base of the fourth transistor Q5 is connected to a common connection point of the nineteenth resistor R19 and the twentieth resistor R20, the other end of the nineteenth resistor R19 is connected to the +5V power, one end of the twentieth resistor R20 is connected to one end of the nineteenth resistor R19 and a base of the fourth transistor Q5, and the other end of the twentieth resistor R20 is connected to a signal ground (AGND). The auxiliary power circuit 40 can provide a suitable low-voltage power supply for each circuit in the overcharge protection circuit, so that each circuit in the overcharge protection circuit can work normally, meanwhile, the auxiliary power circuit 40 can also provide a preset voltage threshold value for the comparison circuit 21, and the comparison circuit 21 compares the preset voltage threshold value with the sampling signal, outputs a control signal, and controls the switch circuit 30. It should be noted that the specific structure of the auxiliary power circuit can be set as required, and is not limited to the structure of the embodiment of the present invention.
With continuing reference to fig. 4, the operation of the overcharge protection circuit will be described with reference to the components of fig. 4, as follows:
the charging circuit 200 charges and stores energy for the rear-end storage battery pack, meanwhile, the sampling circuit 10 samples the voltage OUT _ V + at the output end of the charging circuit, the sampling signal is output by the first remote computing amplifier U1, the sampling signal is input by the non-inverting input end of the second operational amplifier U2, if the output signal of the first operational amplifier U1 is smaller than the preset voltage threshold +5V, it is proved that the charged storage battery pack does not reach the overvoltage protection value, the second operational amplifier U2 outputs a low level signal, the low level signal acts on the base electrode of the first triode Q1, so that the first triode Q1 is cut off, the input end of the optocoupler isolator U3 is cut off, the output end of the optocoupler isolator U3 outputs a high level signal, the high level signal acts on the base electrode of the third triode Q2, so that the third triode Q3 is conducted, and further the PMOS switching tube Q4 is conducted, so that the charging circuit normally charges the, if the sampling signal is greater than the preset voltage threshold value +5V, it is proved that the charged storage battery pack reaches an overvoltage protection value, the second operational amplifier U3 outputs a high level signal, the high level signal acts on the base of the first triode Q1 to enable the first triode Q1 to be conducted, the input end of the optical coupling isolator U3 is connected, the output end of the optical coupling isolator U3 outputs a low level signal, the low level signal acts on the base of the third triode Q3 to enable the third triode Q3 to be cut off, the PMOS switching tube Q4 is cut off, a charging loop is disconnected, the storage battery pack is prevented from being overcharged, the purpose of overcharge protection of the storage battery pack is achieved, the overcharge protection circuit works stably, and overcharge protection can be reliably achieved.
The embodiment of the invention provides an overcharge protection circuit, which is applied to a charging circuit of a photovoltaic power generation energy storage system. The overcharge protection circuit is completely realized by a hardware circuit, has a simple structure and lower cost, has stronger anti-interference capability and is more convenient to popularize and apply.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; within the idea of the invention, also technical features in the above embodiments or in different embodiments may be combined and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or technical features in areas thereof may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present invention.
Claims (10)
1. The utility model provides an overcharge protection circuit, is applied to photovoltaic power generation energy storage system's charge circuit, its characterized in that includes:
the sampling circuit is used for sampling the output voltage of the charging loop;
the control circuit is connected with the sampling circuit and used for generating a control signal according to the output signal of the sampling circuit; and
and the switch circuit is respectively connected with the control circuit and the charging loop and is used for controlling the working state of the charging loop according to the control signal, and the working state comprises a closed circuit state and an open circuit state.
2. The overcharge protection circuit of claim 1, wherein the control circuit comprises:
and the comparison circuit is respectively connected with the sampling circuit and the switch circuit and is used for outputting the control signal to control the working state of the switch circuit according to the sampling signal and a preset voltage threshold, and the working state comprises a closed circuit state and an open circuit state.
3. The overcharge protection circuit of claim 2 wherein the control circuit further comprises:
and the driving circuit is respectively connected with the comparison circuit and the switch circuit and is used for driving the switch circuit.
4. The overcharge protection circuit of claim 3, wherein the control circuit further comprises:
and the optical coupling isolation circuit is respectively connected with the driving circuit and the switch circuit.
5. The overcharge protection circuit of claim 4, wherein the switching circuit comprises: the charging circuit comprises a first switch circuit, a second switch circuit and a third switch circuit which are connected in series, wherein the first switch circuit is also connected with the control circuit, and the third switch circuit is also connected with the charging circuit.
6. The overcharge protection circuit of claim 5, wherein the sampling circuit comprises a first operational amplifier, a non-inverting input terminal of the first operational amplifier is connected to a positive terminal of the output voltage of the charging loop, an inverting input terminal of the first operational amplifier is connected to a negative terminal of the output voltage of the charging loop, and an output terminal of the first operational amplifier is connected to the control circuit.
7. The overcharge protection circuit of claim 6, wherein the comparison circuit comprises a second operational amplifier, a non-inverting input of the second operational amplifier is connected to the output of the first operational amplifier, and an inverting input of the second operational amplifier is connected to the preset voltage threshold.
8. The overcharge protection circuit of claim 7, wherein the drive circuit is a first transistor, a base of the first transistor is connected to the output of the second remote-control amplifier, a collector of the first transistor is connected to the optocoupler isolation circuit, and an emitter of the first transistor is grounded.
9. The overcharge protection circuit of claim 8, wherein the first switch circuit is a second transistor, the second switch circuit is a third diode, the third switch circuit is an MOS switch tube, a base of the second transistor is connected to the optocoupler isolation circuit, a collector of the second transistor is connected to a base of the third transistor, an emitter of the second transistor and an emitter of the third transistor are grounded together, and a collector of the third transistor is connected to a gate of the MOS switch tube to control on or off of the MOS switch tube.
10. A charger, characterized in that the charger comprises:
the photovoltaic power generation system is used for generating electric energy by adopting the photovoltaic system;
the overcharge protection circuit of any one of claims 1-9, connected to the photovoltaic power generation system for overcharge protection; and
and the charging loop is respectively connected with the overcharge protection circuit and an external storage battery pack and is used for charging the external storage battery pack with electric energy generated by the photovoltaic power generation system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911416143.XA CN111009950A (en) | 2019-12-31 | 2019-12-31 | Overcharge protection circuit and charger |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911416143.XA CN111009950A (en) | 2019-12-31 | 2019-12-31 | Overcharge protection circuit and charger |
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| CN111009950A true CN111009950A (en) | 2020-04-14 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201911416143.XA Pending CN111009950A (en) | 2019-12-31 | 2019-12-31 | Overcharge protection circuit and charger |
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| CN (1) | CN111009950A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111896877A (en) * | 2020-07-31 | 2020-11-06 | Oppo广东移动通信有限公司 | Battery detection method and device, electronic equipment and storage medium |
| CN112510641A (en) * | 2020-10-29 | 2021-03-16 | 北京有感科技有限责任公司 | Protective circuit |
-
2019
- 2019-12-31 CN CN201911416143.XA patent/CN111009950A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111896877A (en) * | 2020-07-31 | 2020-11-06 | Oppo广东移动通信有限公司 | Battery detection method and device, electronic equipment and storage medium |
| CN111896877B (en) * | 2020-07-31 | 2023-07-14 | Oppo广东移动通信有限公司 | Battery detection method, device, electronic equipment and storage medium |
| CN112510641A (en) * | 2020-10-29 | 2021-03-16 | 北京有感科技有限责任公司 | Protective circuit |
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