CN220570315U - Overcurrent protection circuit for energy storage converter - Google Patents
Overcurrent protection circuit for energy storage converter Download PDFInfo
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- CN220570315U CN220570315U CN202320077363.XU CN202320077363U CN220570315U CN 220570315 U CN220570315 U CN 220570315U CN 202320077363 U CN202320077363 U CN 202320077363U CN 220570315 U CN220570315 U CN 220570315U
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- resistor
- phase current
- isolating switch
- current comparator
- power supply
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- 238000004146 energy storage Methods 0.000 title claims abstract description 23
- 239000003990 capacitor Substances 0.000 claims description 6
- 238000005070 sampling Methods 0.000 description 6
- 238000004804 winding Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
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Abstract
The utility model provides an overcurrent protection circuit for an energy storage converter, which comprises the following components: (1) The phase current comparator comprises an input end and an output end, wherein the input end of the phase current comparator is connected with the output end of the current sensor. The output end of the phase current comparator is connected with the first end of the intermediate relay coil; (2) The intermediate relay comprises a coil and a normally open contact, wherein the coil comprises a first end and a second end, the first end is connected with the output end of the phase current comparator, and the second end is connected with a power supply; the normally open contact is connected in series in a loop of the isolating switch and the power supply; (3) One end of the isolating switch is connected with a power supply through a normally open contact, and the other end of the isolating switch is grounded; (4) a power supply. The utility model enhances the reliability and safety of the overcurrent stop and simultaneously improves the response speed of the overcurrent stop.
Description
Technical Field
The utility model relates to the field of energy storage converters, in particular to an overcurrent protection circuit for an energy storage converter.
Background
The energy storage converter (PCS) is used for controlling the charging and discharging processes of the storage battery, converting alternating current and direct current, realizing the protective charging and discharging of the battery and ensuring the operation safety of the battery. When the energy storage converter works normally, the direct current side of the energy storage converter is connected with the storage battery, and the alternating current side of the energy storage converter is connected with the power grid. When an energy storage converter has serious faults such as overcurrent, the energy storage converter needs to be disconnected from the storage battery and the power grid as soon as possible (so-called "overcurrent shutdown") in order to avoid the influence of the faults on the storage battery.
In order to realize the overcurrent stop function, the current general method is to judge the sampled current through a main controller, and stop the machine when the sampled current is larger than a certain value, and disconnect the isolating switches on the direct current side and the alternating current side. However, the protection emergency stop mechanism for judging the magnitude of the sampling current by using the main control in the prior art has two technical problems:
firstly, the reliability of the prior art depends on a stable and reliable sampling circuit, and when the sampling circuit fails, the sampling circuit can not be stopped, so that the reliability and the safety of the prior art have defects;
secondly, timeliness of shutdown protection is related to sampling speed and operation speed of the main control, the time of overcurrent protection is 0.5ms at maximum by a complex control algorithm of the energy storage converter, and when serious faults occur, the condition of untimely shutdown is easy to occur, so that hidden danger is brought to safe use of the energy storage converter.
Disclosure of Invention
In order to solve the technical problems of unreliable and untimely overcurrent shutdown protection of an energy storage converter by a main control algorithm in the prior art, the utility model provides an overcurrent protection circuit for the energy storage converter.
Specifically, the utility model provides an overcurrent protection circuit for an energy storage converter, comprising: (1)
A phase current comparator comprising an input end and an output end for judging whether the phase current exceeds a set current protection value, wherein the input end of the phase current comparator is connected with the output end of a current sensor which is connected with the output end of a current sensor "
The device is a detection device which utilizes the Hall magnetic balance principle to complete the induction of the information of the detected current and outputs the information of the detected current into 5 information in a required form, and the current induced by the device is the current of a power grid phase. The output of the phase current comparator
The end is connected with the first end of the coil of the intermediate relay, and when the phase current is larger than a set current protection value, the phase current comparator outputs a low level to enable the coil of the intermediate relay to be electrified; (2) The intermediate relay comprises a coil and a normally open contact,
wherein the coil comprises a first end and a second end, the first end is coupled to the output end of the phase current comparator,
the second end is connected with a power supply, the normally open contact is connected in series in a loop of the isolating switch and the power supply, and the on-off loop between the isolating switch and the power supply is controlled according to whether the intermediate 0 relay coil is electrified or not; (3) Isolation of
One end of the switch is connected with a power supply through a normally open contact, the other end of the switch is grounded, and the isolating switch is opened when power is supplied to the switch and is used for controlling the on-off of the energy storage converter, the storage battery and the power grid, so that the overcurrent shutdown function of the energy storage converter is realized;
(4) And a power supply.
Specifically, the phase current comparator comprises an operational amplifier, wherein the impedance values of the positive pole loop and the negative pole loop of the input end of the operational amplifier 5 are adjustable. The "operational amplifier" is obtained by comparing its inputs
The output potential is adjusted by the positive voltage and the negative voltage of the input end, so that the positive voltage and the negative voltage of the input end can be adjusted by adjusting the impedance values of the positive circuit and the negative circuit of the input end, and the current protection value is set.
Specifically, the phase current comparator comprises first to seventh resistors, a capacitor, an operational amplifier and two 0-pole tubes, wherein a first end of the first resistor is connected with an input end of the phase current comparator, and a second end of the first resistor is connected with the input end of the phase current comparator simultaneously
The first end of the third resistor is connected with the second end of the second resistor, the first end of the second resistor is connected with the second end of the first resistor, the second end of the second resistor is grounded, the second resistor is connected with the capacitor in parallel, the first end of the third resistor is connected with the second end of the first resistor and the first end of the second resistor, the second end of the third resistor is connected with the negative electrode of the input end of the operational amplifier, the second resistor is connected with the capacitor in parallel
The first end of the fourth resistor is grounded, the first end of the fifth resistor is connected with a power supply, the second end of the fifth resistor is connected with the first end of the sixth resistor 5 and the second end of the fourth resistor, and the second end of the sixth resistor is connected with the first end of the seventh resistor and the operational amplifier
The positive electrode of the input end of the device, the second end of the seventh resistor is connected with the output end of the operational amplifier and the cathode of the diode, and the anode of the diode is used as the output end of the phase current comparator.
The 'operational amplifier' controls the output potential by comparing the positive input voltage with the negative input voltage, and simultaneously sets the 'current protection value' by adjusting the impedance values of the first to seventh resistors.
More preferably, each phase circuit of the alternating current power grid is provided with a current sensor and a phase current comparator, and after the output ends of the phase current comparators of each phase circuit of the alternating current power grid are connected in parallel, the output ends of the phase current comparators of each phase circuit of the alternating current power grid are connected with the first ends of the intermediate relay coils.
More preferably, the isolating switch comprises an alternating current isolating switch and a direct current isolating switch, wherein one end of the alternating current isolating switch and one end of the direct current isolating switch are connected with a power supply in parallel, and the other end of the alternating current isolating switch and the other end of the direct current isolating switch are grounded.
More preferably, the device also comprises a fault state display device for displaying whether an overcurrent fault occurs, wherein two ends of the fault state display device are respectively connected with two ends of the intermediate relay coil in parallel and are connected with the output end of the phase current comparator and the power supply.
Compared with the prior art, the energy storage converter has the technical effects that the emergency stop function is realized when the energy storage converter overflows by adding the current comparison circuit, the intermediate relay with two normally open auxiliary contacts and the LED lamp. The device does not relate to a system current sampling circuit, does not need to judge the current through software, does not need to control a direct current isolating switch and an alternating current isolating switch through software, and improves the response speed of overcurrent shutdown while enhancing the reliability and the safety of an overcurrent protection circuit.
Drawings
FIG. 1 is a circuit diagram of an over-current protection circuit according to an embodiment of the present utility model;
fig. 2 is a circuit diagram of a phase current comparator (circuit) according to an embodiment of the present utility model.
Detailed Description
The working principle of the present utility model is described below with reference to the drawings and the embodiments.
The utility model provides an overcurrent protection circuit for an energy storage converter, and one embodiment of the utility model can be connected in a circuit according to fig. 1. The current sensor A is connected with a terminal 1 of the phase A current comparator and is used as the input of the phase A current comparator; the output of the phase A current comparator is connected with the end A2 of the coil of the intermediate relay K1. Similarly, current sensors B and C are connected to terminals 1 of the B and C phase current comparators, respectively, as inputs to the current comparison circuit; the outputs of the B-phase current comparator and the C-phase current comparator are also connected with the end A2 of the coil A1 of the intermediate relay K1.
The coil A1 of the intermediate relay is connected with the VDD power supply, and the coil and the fault indicator light LED are connected in parallel. The intermediate relay K1 comprises two groups of normally open auxiliary contacts. The two connection points of the normally open auxiliary contact 1 are 14 and 11, and the two connection points of the normally open auxiliary contact 2 are 21 and 24. Connection 14 and connection 24 are simultaneously connected to VDD power. The connection point 11 is connected to the shunt winding 36 of the direct current isolating switch QF1, the connection point 21 is connected to the shunt winding F1 of the alternating current isolating switch QF2, the winding 35 of the QF1 and the winding F2 of the QF2 are connected together and are connected to the Ground (GND).
When the outputs of the current sensors A, B and C are larger than a certain value, the output of the phase current comparator is in a low level, the coil of the intermediate relay K1 is powered on, the fault indicator lamp is on, two groups of normally open contacts of the intermediate relay are closed, and the shunt coil of the direct current isolating switch QF1 and the shunt coil of the alternating current isolating switch QF2 are powered on, so that the direct current isolating switch QF1 and the alternating current isolating switch QF2 are disconnected with the energy storage converter at the same time, and the protection purpose is achieved.
An embodiment of the phase current comparator of the present utility model may be circuit connected as per fig. 2. The input 1 of the comparison circuit is connected to one end of a resistor R1, and the other end of R1 is connected to a resistor R3 while being connected to one end of R2. One end of R2 is connected with R1, and the other end is connected with power ground. R2 is connected in parallel with capacitor C1. One end of the resistor R3 is connected with R1 and R2, and the other end is connected with one end of the operational amplifier U1. One end of the resistor R5 is connected with the power supply VDD, and the other end is connected with the resistor R6 and the resistor R4. The other end of the resistor R4 is grounded GND. The other end of the resistor R6 is connected with the resistor R7 and the + of the operational amplifier. The other end of the resistor R7 is connected with the output O of the operational amplifier and the cathode of the diode D1. The anode of the diode D1 is the output of the amplifying circuit and is connected to the terminal 2.
Let the + terminal input voltage of the operational amplifier be VP and the-terminal input voltage be VN. Then there are:
VP＝VDD*R4/(R4+R5)；
VN＝V1*R2/(R1+R2)；
wherein V1 is 1 end input voltage, and VDD is the positive voltage of the DC control power supply.
When VN is greater than VP, the operational amplifier outputs a low level. The comparator outputs about 0.7V by clamping D1. Therefore, by appropriately configuring the values of R1, R2, R4, R5, the magnitude of the current protection value can be set.
The above embodiments are only for illustrating the technical solution of the present utility model, and not for limiting the protection scope of the present utility model. Although the present utility model has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the present utility model, which is intended to be covered by the appended claims.
Claims (6)
1. An overcurrent protection circuit for an energy storage converter, comprising:
(1) A phase current comparator comprising an input and an output, wherein,
the input end of the phase current comparator is connected with the output end of the current sensor,
the output end of the phase current comparator is connected with the first end of the intermediate relay coil;
(2) An intermediate relay comprising a coil and a normally open contact, wherein,
the coil comprises a first end and a second end, the first end is connected with the output end of the phase current comparator, the second end is connected with a power supply,
the normally open contact is connected in series in a loop of the isolating switch and the power supply;
(3) One end of the isolating switch is connected with a power supply through a normally open contact, and the other end of the isolating switch is grounded;
(4) And a power supply.
2. The overcurrent protection circuit of claim 1, wherein the phase current comparator comprises an operational amplifier, and wherein the impedance values of the positive and negative loops at the input of the operational amplifier are adjustable.
3. The overcurrent protection circuit according to claim 2, wherein the phase current comparator includes first to seventh resistors, a capacitor, an operational amplifier, a diode, wherein,
the first end of the first resistor is connected with the input end of the phase current comparator, the second end of the first resistor is simultaneously connected with the first end of the third resistor and the first end of the second resistor,
the first end of the second resistor is connected with the second end of the first resistor, the second end of the second resistor is grounded, the second resistor is connected with a capacitor in parallel,
the first end of the third resistor is connected with the second end of the first resistor and the first end of the second resistor, the second end of the third resistor is connected with the negative electrode of the input end of the operational amplifier,
the first end of the fourth resistor is grounded,
the first end of the fifth resistor is connected with a power supply, the second end of the fifth resistor is connected with the first end of the sixth resistor and the second end of the fourth resistor,
the second end of the sixth resistor is connected with the first end of the seventh resistor and the positive electrode of the input end of the operational amplifier,
the second end of the seventh resistor is connected with the output end of the operational amplifier and the cathode of the diode,
the anode of the diode serves as the output of the phase current comparator.
4. The overcurrent protection circuit of claim 1, wherein each phase circuit of the ac power grid is provided with a current sensor and a phase current comparator, and wherein the output ends of the phase current comparators of each phase circuit of the ac power grid are connected in parallel and then connected to the first end of the intermediate relay coil.
5. The overcurrent protection circuit of claim 1, wherein the isolating switch comprises an ac isolating switch and a dc isolating switch, one end of the ac isolating switch and one end of the dc isolating switch are connected in parallel and then connected with a power supply, and the other end of the ac isolating switch and the dc isolating switch are grounded.
6. The overcurrent protection circuit of claim 1, further comprising a fault status display device having two ends connected in parallel with the two ends of the intermediate relay coil, respectively, and coupled to the output of the phase current comparator and the power supply.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320077363.XU CN220570315U (en) | 2023-01-10 | 2023-01-10 | Overcurrent protection circuit for energy storage converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320077363.XU CN220570315U (en) | 2023-01-10 | 2023-01-10 | Overcurrent protection circuit for energy storage converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220570315U true CN220570315U (en) | 2024-03-08 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202320077363.XU Active CN220570315U (en) | 2023-01-10 | 2023-01-10 | Overcurrent protection circuit for energy storage converter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN220570315U (en) |
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2023
- 2023-01-10 CN CN202320077363.XU patent/CN220570315U/en active Active
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