CN213275734U - Isolated bus voltage sampling circuit - Google Patents
Isolated bus voltage sampling circuit Download PDFInfo
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- CN213275734U CN213275734U CN202021454106.6U CN202021454106U CN213275734U CN 213275734 U CN213275734 U CN 213275734U CN 202021454106 U CN202021454106 U CN 202021454106U CN 213275734 U CN213275734 U CN 213275734U
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Abstract
The utility model discloses an keep apart busbar voltage sampling circuit, include: a transformer, a primary winding of which is connectable with an external bus; and the input end of the linear processing module is connected with the secondary winding of the transformer, and the output end of the linear processing module can be connected with an external control module. The bus and the linear processing module are isolated through the transformer, the voltage of a primary winding of the transformer and the voltage of a secondary winding of the transformer are in a proportional relation, namely, linearly related, the linear processing module can acquire a voltage value obtained after the bus is converted in proportion from the secondary winding of the transformer, and the linear processing module linearly amplifies or reduces the acquired voltage value to form a sampling voltage value with a proper size and transmits the sampling voltage value to a subsequent control module. Therefore, a photoelectric coupler or a single chip microcomputer is not needed, the sampling voltage value can be accurately obtained in a linear mode through the matching of the transformer and the linear processing module, and the implementation cost is low.
Description
Technical Field
The utility model relates to a voltage detection field, in particular to isolated bus voltage sampling circuit.
Background
In the process of equipment work, the voltage of the bus is often required to be detected and sampled so as to obtain the voltage value of the bus and transmit the voltage value to the control module, and then the control module is convenient to regulate and control, and the stable work of the equipment is maintained.
In the prior art, in order to reduce interference, an isolation detection mode is generally adopted, for example, a photoelectric coupler is used, a bus on an input side is isolated from a control module on an output side by using a photoelectric isolation effect of the photoelectric coupler, and voltage detection sampling is realized. There is also a structure using a linear isolation optocoupler, so that the voltages at the input end and the output end are in a linear relationship, but the implementation cost is high. Or after the singlechip is used for sampling the bus voltage, the voltage value is sent to the control module through isolated communication, but the implementation circuit is complex and the cost is high.
SUMMERY OF THE UTILITY MODEL
The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, the utility model provides an keep apart busbar voltage sampling circuit, it realizes keeping apart the effect earlier through the transformer to can detect busbar voltage with linear mode, the implementation cost is low.
According to the utility model discloses an keep apart busbar voltage sampling circuit, include: a transformer, a primary winding of which is connectable with an external bus; and the input end of the linear processing module is connected with the secondary winding of the transformer, and the output end of the linear processing module can be connected with an external control module.
According to the utility model discloses keep apart busbar voltage sampling circuit has following beneficial effect at least: the bus and the linear processing module are isolated through the transformer, the voltage of a primary winding of the transformer and the voltage of a secondary winding of the transformer are in a proportional relation, namely, linearly related, the linear processing module can acquire a voltage value obtained after the bus is converted in proportion from the secondary winding of the transformer, and the linear processing module linearly amplifies or reduces the acquired voltage value to form a sampling voltage value with a proper size and transmits the sampling voltage value to a subsequent control module. Therefore, a photoelectric coupler or a single chip microcomputer is not needed, the sampling voltage value can be accurately obtained in a linear mode through the matching of the transformer and the linear processing module, and the implementation cost is low.
According to some embodiments of the utility model, linear processing module includes the peak detection unit, the input of peak detection unit with the secondary winding of transformer is connected, the output of peak detection unit can be connected with external control module.
According to some embodiments of the present invention, the peak detection unit comprises a comparison unit and a voltage holding unit, the first input end of the comparison unit is connected to the secondary winding of the transformer, the second input end of the comparison unit and the output end of the comparison unit are both connected to the voltage holding unit, and the voltage holding unit can be connected to an external control module.
According to some embodiments of the present invention, the linear processing module further comprises a proportional amplification unit, an input end of the proportional amplification unit is connected to the voltage holding unit, and an output end of the proportional amplification unit can be connected to the external control module.
According to some embodiments of the utility model, linear processing module still includes the step-down filtering unit, the input of step-down filtering unit with the secondary winding of transformer is connected, the output of step-down filtering unit with comparing unit's first input is connected.
According to some embodiments of the invention, the comparison unit comprises an operational amplifier U2, the voltage holding unit comprises a diode D2, a resistor R4 and a capacitor C4; a first input end of the operational amplifier U2 is connected to an output end of the buck filter unit, a second input end of the operational amplifier U2 is connected to one end of the diode D2, one end of the resistor R4, one end of the capacitor C4 and an input end of the proportional amplifier unit, respectively, and outputs of the operational amplifier U2 are all connected to the other end of the diode D2; the other end of the resistor R4 and the other end of the capacitor C4 are grounded.
According to some embodiments of the present invention, the proportional amplification unit comprises a resistor R3, a resistor R5, a resistor R6, and an operational amplifier U1; one end of the resistor R5 is connected to the voltage holding unit, and the other end of the resistor R5 is connected to one end of the resistor R3 and the first input end of the operational amplifier U1; a second input end of the operational amplifier U1 is connected to one end of the resistor R6, and an output end of the operational amplifier U1 is connected to the other end of the resistor R3 and an external control module, respectively; the other end of the resistor R6 is grounded.
According to some embodiments of the present invention, the buck filter unit comprises a resistor R1, a resistor R2, and a capacitor C3; one end of the resistor R2 is connected with the secondary winding of the transformer, and the other end of the resistor R2 is respectively connected with one end of the resistor R3, one end of the capacitor C3 and the first input end of the operational amplifier U2; the other end of the resistor R1 and the other end of the capacitor C3 are grounded.
According to the utility model discloses a some embodiments still include auxiliary power supply unit, auxiliary power supply unit's input with the secondary winding of transformer is connected, auxiliary power supply unit's output with linear processing module's supply end is connected.
According to some embodiments of the present invention, the auxiliary power supply unit comprises a diode D1 and a capacitor C2, an anode of the diode D1 is connected to the secondary winding of the transformer, a cathode of the diode D1 is connected to one end of the capacitor C2 and the power supply terminal of the linear processing module, respectively, and the other end of the capacitor C2 is grounded.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a circuit diagram of one embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.
In the description of the present invention, it should be understood that the orientation or positional relationship indicated with respect to the orientation description, such as up, down, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
In the description of the present invention, if there are first and second descriptions for distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the precedence of the indicated technical features.
In the description of the present invention, unless there is an explicit limitation, the words such as setting, installation, connection, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in combination with the specific contents of the technical solution.
As shown in fig. 1, according to the utility model discloses an isolated bus voltage sampling circuit includes: a transformer 100, a primary winding of the transformer 100 being connectable with an external bus; a linear processing module 200, an input terminal of the linear processing module 200 being connected to the secondary winding of the transformer 100, an output terminal of the linear processing module 200 being connectable to an external control module.
The bus and the linear processing module 200 are isolated by the transformer 100, and the voltage of the primary winding of the transformer 100 and the voltage of the secondary winding are in a proportional relationship, i.e. linearly related, the linear processing module 200 can obtain the voltage value after the bus is converted in proportion from the secondary winding of the transformer 100, and the linear processing module 200 linearly amplifies or reduces the obtained voltage value to form a sampling voltage value with a proper size and transmits the sampling voltage value to a subsequent control module. Therefore, a sampling voltage value can be accurately obtained in a linear mode by matching the transformer 100 with the linear processing module 200 without using a photoelectric coupler or a single chip microcomputer, and the implementation cost is low.
In electrical equipment, a transformer 100 is typically used to regulate the voltage, which is then transmitted to various functional modules for power. The linear processing module 200 may be an embodiment connected to such a transformer 100, and the transformer 100 may form a plurality of secondary windings by tapping, one of which is used for connecting to the linear processing module 200, and the rest of which may be used for supplying power to the functional module, thereby being beneficial to saving cost and reducing circuit complexity.
Referring to fig. 1, in some embodiments of the present invention, the linear processing module 200 includes a peak detection unit 210, an input of the peak detection unit 210 is connected with the secondary winding of the transformer 100, and an output of the peak detection unit 210 can be connected with an external control module.
The peak value detection unit 210 detects the voltage peak value of the secondary winding of the transformer 100, that is, the voltage peak value of the bus is sampled, so that the maximum value of the voltage fluctuation of the bus can be reflected, a subsequent control module can regulate and control according to the voltage peak value, and the working stability of the whole equipment is maintained.
Referring to fig. 1, in some embodiments of the present invention, the peak detecting unit 210 includes a comparing unit 211 and a voltage holding unit 212, a first input terminal of the comparing unit 211 is connected to the secondary winding of the transformer 100, a second input terminal of the comparing unit 211 and an output terminal of the comparing unit 211 are both connected to the voltage holding unit 212, and the voltage holding unit 212 is capable of being connected to an external control module.
The voltage holding unit 212 maintains a certain voltage value, the comparing unit 211 compares the voltage value of the secondary winding of the transformer 100 at the first input terminal with the voltage value of the voltage holding unit 212 at the second input terminal, when the voltage value of the secondary winding of the transformer 100 is greater than the voltage value of the voltage holding unit 212, the comparing unit 211 outputs an electrical signal, so that the voltage value of the voltage holding unit 212 rises to be equal to the voltage value of the secondary winding of the transformer 100; when the voltage value of the voltage holding unit 212 is greater than the voltage value of the secondary winding of the transformer 100, it does not act. Thus, the voltage holding unit 212 can be held at the maximum voltage value of the secondary winding of the transformer 100, that is, the peak voltage value, and the purpose of peak detection can be achieved.
Referring to fig. 1, in some embodiments of the present invention, the linear processing module 200 further includes a proportional amplifying unit 220, an input end of the proportional amplifying unit 220 is connected to the voltage holding unit 212, and an output end of the proportional amplifying unit 220 can be connected to an external control module.
The peak voltage is scaled up by the scaling up unit 220, so that the peak voltage is suitable for the subsequent control module to receive and process, the final output voltage value range is within the input voltage range of the control module, and the reliability is improved.
Referring to fig. 1, in some embodiments of the present invention, the linear processing module 200 further includes a step-down filtering unit 230, an input end of the step-down filtering unit 230 is connected with the secondary winding of the transformer 100, and an output end of the step-down filtering unit 230 is connected with the first input end of the comparing unit 211.
When the transformer 100 performs voltage conversion, the secondary winding of the transformer 100 may cause voltage spike due to the leakage inductance two, which affects the accuracy of voltage detection sampling and may damage subsequent circuit devices. To this end, the voltage reduction filtering unit 230 is provided to perform voltage reduction filtering on the electrical signal on the secondary winding of the transformer 100 to remove voltage spikes, so that the voltage of the secondary winding of the transformer 100 is more stable, which is beneficial to improving the accuracy of voltage detection sampling, protecting subsequent circuit devices, and improving the reliability of the circuit.
Referring to fig. 1, in some embodiments of the present invention, the comparing unit 211 includes an operational amplifier U2, and the voltage holding unit 212 includes a diode D2, a resistor R4, and a capacitor C4; a first input end of the operational amplifier U2 is connected to an output end of the buck filter unit 230, a second input end of the operational amplifier U2 is connected to one end of the diode D2, one end of the resistor R4, one end of the capacitor C4 and an input end of the proportional amplification unit 220, respectively, and outputs of the operational amplifier U2 are connected to the other end of the diode D2; the other end of the resistor R4 and the other end of the capacitor C4 are grounded.
When the voltage value of the secondary winding of the transformer 100 is larger than that of the capacitor C4, the operational amplifier U2 outputs current so that the voltage value of the capacitor C4 is equal to that of the secondary winding of the transformer 100; when the voltage value of the secondary winding of the transformer 100 is smaller than the voltage value of the capacitor C4, the capacitor C4 is limited to discharge to the operational amplifier U2 by the unidirectional conduction characteristic of the diode D2, and the resistance value of the resistor R4 is low, so that the electric energy discharge of the capacitor C4 is slowed down, and the electric voltage value is kept stable. Thereby making the voltage value of the capacitor C4 equal to the maximum voltage value, i.e. the peak value, of the secondary winding of the transformer 100. When the voltage value of the secondary winding of the transformer 100 is smaller than the voltage value of the capacitor C4, the operational amplifier U2 can generate a larger current to make the voltage value of the capacitor C4 equal to the voltage value of the secondary winding of the transformer 100, which is beneficial to improving the accuracy of the peak value.
Referring to fig. 1, in some embodiments of the present invention, the proportional amplifying unit 220 includes a resistor R3, a resistor R5, a resistor R6, and an operational amplifier U1; one end of the resistor R5 is connected to the voltage holding unit 212, and the other end of the resistor R5 is connected to one end of the resistor R3 and the first input terminal of the operational amplifier U1, respectively; a second input end of the operational amplifier U1 is connected with one end of the resistor R6, and an output end of the operational amplifier U1 is respectively connected with the other end of the resistor R3 and the external control module; the other end of the resistor R6 is connected to ground.
The operational amplifier U1, the resistor R3, the resistor R5, and the resistor R6 cooperate to form a proportional operational circuit, which can amplify the input voltage, i.e., the voltage value of the capacitor C4, and finally form a sampling voltage with a suitable size to be transmitted to a subsequent control module. The input impedance of the proportional operation circuit is large, so that the capacitor C4 can be prevented from discharging rapidly, and the voltage value of the capacitor C4 can be kept stably.
Referring to fig. 1, in some embodiments of the present invention, the buck filter unit 230 includes a resistor R1, a resistor R2, and a capacitor C3; one end of the resistor R2 is connected with the secondary winding of the transformer 100, and the other end of the resistor R2 is respectively connected with one end of the resistor R3, one end of the capacitor C3 and the first input end of the operational amplifier U2; the other end of the resistor R1 and the other end of the capacitor C3 are grounded.
A voltage dividing circuit is formed by the resistor R1 and the resistor R2 to step down the voltage of the secondary winding of the transformer 100, remove spike voltages by filtering action of the capacitor C3, and then transmit to the first input terminal of the operational amplifier U2. The voltage reduction processing of the voltage by the voltage division circuit formed by the resistor R1 and the resistor R2 is linear, and the accuracy of the final sampling voltage is not influenced.
Referring to fig. 1, in some embodiments of the present invention, an auxiliary power supply unit 300 is further included, an input end of the auxiliary power supply unit 300 is connected to the secondary winding of the transformer 100, and an output end of the auxiliary power supply unit 300 is connected to a power supply end of the linear processing module 200.
The auxiliary power supply unit 300 obtains electric energy from the secondary winding of the transformer 100 and then supplies power to the linear processing module 200, and a special power supply module is not required to be additionally arranged, so that the circuit structure is simplified, and the cost is saved.
Referring to fig. 1, in some embodiments of the present invention, the auxiliary power supply unit 300 includes a diode D1 and a capacitor C2, an anode of the diode D1 is connected to the secondary winding of the transformer 100, a cathode of the diode D1 is connected to one end of the capacitor C2 and a power supply terminal of the linear processing module 200, and the other end of the capacitor C2 is grounded.
The diode D1 obtains power from the secondary winding of the transformer 100, and then forms a dc power signal through the rectifying action of the diode D1 and the filtering and voltage-stabilizing action of the capacitor C2, and transmits the dc power signal to the linear processing module 200 for supplying power, specifically, to the operational amplifier U1 and the operational amplifier U2.
Referring to fig. 1, as an embodiment, the pin 6 of the primary winding and the pin 9 of the secondary winding of the transformer 100 are terminals with the same name, and when the switching tube Q1 is turned on, the pin 9 of the secondary winding of the transformer 100 is negative because the pin 10 of the secondary winding of the transformer 100 is grounded. Transformer deviceThe voltage of the primary winding of 100 is VIN, the number of turns of the primary winding of 100 is NP, the number of turns of the secondary winding of 100 is NS1, and the induced voltage of the pin 9 of the secondary winding of 100 is
The voltage is subjected to voltage reduction processing by a resistor R1 and a resistor R2 and filtering processing by a capacitor C3, spikes caused by leakage inductance are removed, and then the voltage is transmitted to a first input end, namely a non-inverting input end and a positive input end of an operational amplifier U2
The operational amplifier U2 outputs a negative voltage, and the diode D2 is turned on, so that the voltage at the second input terminal of the operational amplifier U2, i.e., the inverting input terminal, is equal to the voltage at the forward input terminal, and the voltage at the capacitor C4 is equal to the voltage VS 1. When the absolute value of the voltage VS1 is decreased, the operational amplifier U2 outputs a positive voltage, but the voltage value of the capacitor C4 is inconveniently maintained due to the unidirectional conduction of the diode D2, so that the voltage value of the capacitor C4 keeps the maximum value of the negative voltage VS1, and even after the switching tube Q1 is turned off, the voltage of the capacitor C4 keeps the maximum value of the negative voltage VS1
The operational amplifier U1, the resistor R3, the resistor R5 and the resistor R6 form an inverting proportional amplifier circuit, and the VSPKN voltage is converted into voltage through inverting amplification processing
For use by later stage circuitry, such as a control module. Due to the fact that
The ratio of the number of turns of the secondary coil to the number of turns of the primary coil is constant, andouter cover
And
the resistance values of the resistors R1 to R5 are also constant, so Vo is K × VIN, where K is a constant related to the number of turns of the secondary coil, the number of turns of the primary coil, and the resistance values of the resistors R1 to R5, so that it is obvious that the finally output sampling voltage Vo is linearly related to the bus input voltage VIN.
The invention is not limited to the above embodiments, and those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the invention, and such equivalent modifications or substitutions are included in the scope defined by the claims of the present application.
Claims (10)
1. An isolated bus voltage sampling circuit, comprising:
a transformer (100), a primary winding of the transformer (100) being connectable with an external bus;
a linear processing module (200), an input of the linear processing module (200) being connected with the secondary winding of the transformer (100), an output of the linear processing module (200) being connectable with an external control module.
2. The isolated bus voltage sampling circuit of claim 1, wherein: the linear processing module (200) comprises a peak detection unit (210), an input of the peak detection unit (210) is connected with the secondary winding of the transformer (100), and an output of the peak detection unit (210) is connectable with an external control module.
3. The isolated bus voltage sampling circuit of claim 2, wherein: the peak detection unit (210) comprises a comparison unit (211) and a voltage holding unit (212), wherein a first input end of the comparison unit (211) is connected with a secondary winding of the transformer (100), a second input end of the comparison unit (211) and an output end of the comparison unit (211) are both connected with the voltage holding unit (212), and the voltage holding unit (212) can be connected with an external control module.
4. The isolated bus voltage sampling circuit of claim 3, wherein: the linear processing module (200) further comprises a proportional amplification unit (220), wherein the input end of the proportional amplification unit (220) is connected with the voltage holding unit (212), and the output end of the proportional amplification unit (220) can be connected with an external control module.
5. The isolated bus voltage sampling circuit of claim 4, wherein: the linear processing module (200) further comprises a buck filter unit (230), wherein an input end of the buck filter unit (230) is connected with the secondary winding of the transformer (100), and an output end of the buck filter unit (230) is connected with a first input end of the comparison unit (211).
6. The isolated bus voltage sampling circuit of claim 5, wherein: the comparison unit (211) comprises an operational amplifier U2, and the voltage holding unit (212) comprises a diode D2, a resistor R4 and a capacitor C4; a first input end of the operational amplifier U2 is connected with an output end of the buck filtering unit (230), a second input end of the operational amplifier U2 is respectively connected with one end of the diode D2, one end of the resistor R4, one end of the capacitor C4 and an input end of the proportional amplifying unit (220), and outputs of the operational amplifier U2 are connected with the other end of the diode D2;
the other end of the resistor R4 and the other end of the capacitor C4 are grounded.
7. The isolated bus voltage sampling circuit of claim 6, wherein: the proportional amplifying unit (220) comprises a resistor R3, a resistor R5, a resistor R6 and an operational amplifier U1;
one end of the resistor R5 is connected with the voltage holding unit (212), and the other end of the resistor R5 is respectively connected with one end of the resistor R3 and a first input end of the operational amplifier U1;
a second input end of the operational amplifier U1 is connected to one end of the resistor R6, and an output end of the operational amplifier U1 is connected to the other end of the resistor R3 and an external control module, respectively;
the other end of the resistor R6 is grounded.
8. The isolated bus voltage sampling circuit of claim 7, wherein: the buck filter unit (230) comprises a resistor R1, a resistor R2 and a capacitor C3;
one end of the resistor R2 is connected with the secondary winding of the transformer (100), and the other end of the resistor R2 is respectively connected with one end of the resistor R3, one end of a capacitor C3 and a first input end of the operational amplifier U2;
the other end of the resistor R1 and the other end of the capacitor C3 are grounded.
9. The isolated bus voltage sampling circuit of claim 1, wherein: the transformer (100) further comprises an auxiliary power supply unit (300), wherein the input end of the auxiliary power supply unit (300) is connected with the secondary winding of the transformer (100), and the output end of the auxiliary power supply unit (300) is connected with the power supply end of the linear processing module (200).
10. The isolated bus voltage sampling circuit of claim 9, wherein: the auxiliary power supply unit (300) comprises a diode D1 and a capacitor C2, wherein the anode of the diode D1 is connected with the secondary winding of the transformer (100), the cathode of the diode D1 is respectively connected with one end of the capacitor C2 and the power supply end of the linear processing module (200), and the other end of the capacitor C2 is grounded.
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| CN202021454106.6U CN213275734U (en) | 2020-07-22 | 2020-07-22 | Isolated bus voltage sampling circuit |
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| CN202021454106.6U CN213275734U (en) | 2020-07-22 | 2020-07-22 | Isolated bus voltage sampling circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114740246A (en) * | 2022-03-25 | 2022-07-12 | 苏州熠品质量技术服务有限公司 | Automatic measuring device for working voltage of transformer |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114740246A (en) * | 2022-03-25 | 2022-07-12 | 苏州熠品质量技术服务有限公司 | Automatic measuring device for working voltage of transformer |
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