CN109324218B - Capacitance voltage division direct current bus voltage division state detection circuit - Google Patents
Capacitance voltage division direct current bus voltage division state detection circuit Download PDFInfo
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- CN109324218B CN109324218B CN201710642987.0A CN201710642987A CN109324218B CN 109324218 B CN109324218 B CN 109324218B CN 201710642987 A CN201710642987 A CN 201710642987A CN 109324218 B CN109324218 B CN 109324218B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0084—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring voltage only
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
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Abstract
The invention discloses a capacitor voltage division direct current bus voltage division state detection circuit which comprises a plurality of detection circuits, wherein the input ends of the detection circuits are connected with capacitors in a one-to-one correspondence mode, each detection circuit comprises a first differential filter circuit, a second differential filter circuit and a comparison circuit which are sequentially connected, the input voltage of the first differential filter circuit is the voltage between the corresponding capacitor and a common end, the output end of a first differential filter is respectively connected with the second differential filter circuit and the second differential filter circuit in the detection circuit corresponding to the other adjacent capacitor, the output voltage of the second differential filter circuit is proportional to the voltage of the corresponding capacitor, and the comparison circuit is used for outputting a high level or a low level according to the comparison of the output voltage of the second differential filter circuit and a preset value. The detection circuit has the advantages of simple structure, small volume, strong anti-interference capability, low cost and the like.
Description
Technical Field
The invention mainly relates to the technical field of power systems, in particular to a capacitor voltage division direct current bus voltage division state detection circuit.
Background
In the fields of power supply and transformation equipment, industrial converter devices, special devices and the like of an electric power system, capacitive energy storage is required to be adopted in a direct current bus link in many application occasions. In consideration of cost schemes, the energy storage capacitor is often in a form of capacitor series (parallel) connection, so that a capacitor with a lower voltage level can be adopted to meet application requirements. In the case of voltage division by the capacitors, it is necessary to detect the voltage of each stage of capacitor, and detect whether the voltage division is uniform or whether the voltage at the two ends of the capacitor exceeds a set value. However, the existing technical solutions have more or less problems: 1. the high-voltage loop and the control loop are not isolated, and the measured direct-current voltage signal is easily interfered; 2. some photoelectric couplers are used as isolation devices, which has the advantages that the volume of the isolation part can be made small, but the circuit of the type needs a power supply on the primary side or the secondary side of the isolation part, so the cost is increased, and on the other hand, because the photoelectric couplers have certain attenuation along with time, the reliability and the accuracy of the circuit can be reduced after long-time operation; 3. and the transformer is partially adopted for isolation and is suitable for measuring alternating voltage, but the application of the transformer in the high-voltage field is limited by the huge volume or cost of the transformer.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: aiming at the technical problems in the prior art, the invention provides the capacitance voltage division direct current bus voltage division state detection circuit which is simple in structure, high in reliability, small in size and low in cost.
In order to solve the technical problems, the technical scheme provided by the invention is as follows:
the input ends of the detection circuits are connected with capacitors in a one-to-one correspondence mode, each detection circuit comprises a first differential filter circuit, a second differential filter circuit and a comparison circuit which are sequentially connected, the input voltage of the first differential filter circuit is the voltage between the corresponding capacitor and a common end, the output end of the first differential filter circuit is respectively connected with the second differential filter circuit and a second differential filter circuit in the detection circuit corresponding to the other adjacent capacitor, the output voltage of the second differential filter circuit is proportional to the voltage of the corresponding capacitor, and the comparison circuit is used for comparing the output voltage of the second differential filter circuit with a preset value to output a high level or a low level.
As a further improvement of the above technical solution:
the output ends of the detection loops are connected with a logic circuit, and the logic circuit is used for receiving output level signals of the comparison circuits in the detection loops and carrying out synthesis to judge the voltage division state of the direct current bus capacitor.
The logic circuit comprises a diode and gate.
The first differential filter circuit comprises an operational amplifier U1, wherein a resistor R1 is connected in series with an inverting input end of the U1, a resistor R2 is connected in series with a non-inverting input end of the U1, a resistor R3 is connected in series between the non-inverting input end and a common end of the U1, a capacitor C3 is connected in parallel with the resistor R3, a resistor R4 is connected in series between the inverting input end and an output end of the U4, a capacitor C4 is connected in parallel with the resistor R5 is connected in series with an output end of the U1, and a capacitor C5 is connected in series between the.
The second differential filter circuit comprises an operational amplifier U2, wherein a resistor R6 is connected in series with the inverting input end of the U2, a resistor R7 is connected in series with the non-inverting input end, a resistor R9 is connected in series between the non-inverting input end and the common end, a capacitor C7 is connected in parallel with the resistor R9, a resistor R8 is connected in series between the inverting input end and the output end, and a capacitor C6 is connected in parallel with the resistor R8.
Compared with the prior art, the invention has the advantages that:
the capacitance voltage division direct current bus voltage division state detection circuit disclosed by the invention adopts the differential filter circuit to carry out signal isolation, ensures that an output signal is not interfered, has strong anti-interference performance, is simple in structure, small in size and low in cost, can effectively weaken interference noise through multi-stage filtering, and has high reliability.
Drawings
Fig. 1 is a schematic diagram of a circuit of the present invention in which two capacitors are connected in series to divide voltage.
Fig. 2 is a schematic circuit diagram of two capacitors according to the present invention.
Fig. 3 is a schematic diagram of a first differential filter circuit according to the present invention.
Fig. 4 is a schematic diagram of one of the second differential filter circuits according to the present invention.
Fig. 5 is a schematic diagram of another second differential filter circuit according to the present invention.
FIG. 6 is a schematic diagram of a comparison circuit of the present invention.
Fig. 7 is a schematic diagram of a logic circuit of the present invention.
Fig. 8 is a schematic diagram of the voltage division of the three capacitors in series in the present invention.
FIG. 9 is a schematic diagram of a circuit corresponding to three capacitors of the present invention.
Detailed Description
The invention is further described below with reference to the figures and the specific embodiments of the description.
As shown in fig. 1 to 7, the circuit for detecting a voltage division state of a capacitor voltage division dc bus according to this embodiment includes a plurality of detection circuits, input ends of the plurality of detection circuits are connected to respective capacitors on a dc bus in a one-to-one correspondence manner, each detection circuit includes a first differential filter circuit, a second differential filter circuit, and a comparison circuit, which are connected in sequence, an input voltage of the first differential filter circuit is a voltage between the corresponding capacitor and a common end, an output end of the first differential filter circuit is connected to the second differential filter circuit and a second differential filter circuit in the detection circuit corresponding to another adjacent capacitor, respectively, an output voltage of the second differential filter circuit is proportional to a voltage of the corresponding capacitor, and the comparison circuit is configured to output a high level or a low level according to a comparison between an output voltage of the second differential filter circuit and a preset value. The capacitance voltage division direct current bus voltage division state detection circuit adopts the differential filter circuit to carry out signal isolation, ensures that output signals are not interfered, has simple structure, small volume and low cost, can effectively weaken interference noise by multistage filtering, and has high reliability.
As shown in fig. 2, in this embodiment, the number of the capacitors connected in series for voltage division is two, corresponding to two detection loops, output ends of the two detection loops are both connected to a logic circuit, and the logic circuit is configured to receive output level signals of the comparison circuits in the detection loops and synthesize the output level signals to determine a voltage division state of the dc bus capacitor. The logic circuit comprises a diode and a gate, and a low level is output as long as the voltage at two ends of one capacitor exceeds a preset value.
As shown in fig. 3, in the present embodiment, the first differential filter circuit includes an operational amplifier U1, a resistor R1 is connected in series to an inverting input terminal of U1, a resistor R2 is connected in series to a non-inverting input terminal, a resistor R3 is connected in series between the non-inverting input terminal and a common terminal, a capacitor C3 is connected in parallel to a resistor R3, a resistor R4 is connected in series between the inverting input terminal and an output terminal, a capacitor C4 is connected in parallel to a resistor R4, a resistor R5 is connected in series to an output terminal of U1, and a capacitor C5 is connected in series between the output terminal and the. The first differential filter circuit is used for converting a high-voltage signal into a small-voltage signal, filtering and limiting current. Wherein Vp and Vn are inputted from Vin1 and Vin2, respectively, wherein R1 and R2 use resistors of large resistance, which function to reduce the input current. R5 and C5 are used for output current limitation and output signal filtering, respectively, and finally, the output small voltage signal V1 is K1 (Vp-Vn), and the value of K1 is related to the resistance value of the present part of circuit, and is a certain constant. Similarly, Vm and Vn pass through Vin1 and Vin2 of another independent first differential filter circuit, and finally output a small voltage signal V2 ═ K1 ═ Vm-Vn.
As shown in fig. 4 and 5, in the present embodiment, the second differential filter circuit includes an operational amplifier U2, a resistor R6 is connected in series to the inverting input terminal of U2, a resistor R7 is connected in series to the non-inverting input terminal, a resistor R9 is connected in series between the non-inverting input terminal and the common terminal, a capacitor C7 is connected in parallel to the resistor R9, a resistor R8 is connected in series between the inverting input terminal and the output terminal, and a capacitor C6 is connected in parallel to the resistor R8. The second differential filter circuit is used for carrying out second filtering on the small voltage signal. V1 and V2 are converted to V3 ═ K2 ═ Vp-Vm, where (Vp-Vm) is the voltage across C1, one of the measured signals. U2 is an operational amplifier, and the value of K2 is related to the resistance value of the circuit and is a definite constant.
In this embodiment, the comparison circuit is configured to compare the conditioned small voltage signal with a reference signal and output a digital signal in a high-low level form. As shown in fig. 6, the signals under test V3 and V4 are compared with the reference signal VREF, respectively, and when the signal under test is greater than VREF, a low level is output. And when the measured signal is less than VREF, outputting high level.
In this embodiment, the truth table corresponding to the corresponding logic circuit is as follows:
| S1 | S2 | S0 |
| 0 | 0 | 0 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 1 |
wherein S1 ═ 0: the voltage across C1 is greater than the set value;
s1 ═ 1: the voltage across C1 is less than the set value;
s2 ═ 0: the voltage across C2 is greater than the set value;
s2 ═ 1: the voltage across C2 is less than the set value;
as can be seen from the truth table, when the voltages across C1 and C2 are both less than the set point, a high is output. And outputting low level as long as the voltage at two ends of one capacitor exceeds a set value.
Similarly, the detection circuit of the present invention can also be applied to the case of multiple capacitors (the number of capacitors is greater than or equal to 3), as shown in fig. 8 and 9, taking three capacitors as an example, the voltages to be detected are the voltage across Cs1 (Vp-Vp1), the voltage across Cs2 (Vp1-Vp2), and the voltage across Cs3 (Vp 2-Vn).
The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention.
Claims (2)
1. The capacitor voltage division direct current bus voltage division state detection circuit is characterized by comprising a plurality of detection circuits, wherein the input ends of the detection circuits are connected with capacitors in a one-to-one correspondence mode, each detection circuit comprises a first differential filter circuit, a second differential filter circuit and a comparison circuit which are sequentially connected, the input voltage of the first differential filter circuit is the voltage between the corresponding capacitor and a common end, the output end of the first differential filter circuit is respectively connected with the second differential filter circuit and a second differential filter circuit in the detection circuit corresponding to another adjacent capacitor, the output voltage of the second differential filter circuit is proportional to the voltage of the corresponding capacitor, and the comparison circuit is used for outputting a high level or a low level according to the comparison of the output voltage of the second differential filter circuit and a preset value;
the output ends of the detection loops are connected with a logic circuit, and the logic circuit is used for receiving output level signals of the comparison circuits in the detection loops and carrying out synthesis to judge the voltage division state of the direct current bus capacitor;
the first differential filter circuit comprises an operational amplifier U1, wherein a resistor R1 is connected in series with an inverting input end of the U1, a resistor R2 is connected in series with a non-inverting input end of the U1, a resistor R3 is connected in series between the non-inverting input end and a common end of the U1, a capacitor C3 is connected in parallel with a resistor R3, a resistor R4 is connected in series between the inverting input end and an output end of the U4, a capacitor C4 is connected in parallel with the resistor R5 is connected in series with an output end of the U1, and a capacitor C5 is connected in series between the;
the second differential filter circuit comprises an operational amplifier U2, wherein a resistor R6 is connected in series with the inverting input end of the U2, a resistor R7 is connected in series with the non-inverting input end, a resistor R9 is connected in series between the non-inverting input end and the common end, a capacitor C7 is connected in parallel with the resistor R9, a resistor R8 is connected in series between the inverting input end and the output end, and a capacitor C6 is connected in parallel with the resistor R8.
2. The capacitance-divided direct current bus voltage division state detection circuit of claim 1, wherein the logic circuit comprises a diode and gate.
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|---|---|---|---|
| CN201710642987.0A CN109324218B (en) | 2017-07-31 | 2017-07-31 | Capacitance voltage division direct current bus voltage division state detection circuit |
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| CN201710642987.0A CN109324218B (en) | 2017-07-31 | 2017-07-31 | Capacitance voltage division direct current bus voltage division state detection circuit |
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| CN109324218A CN109324218A (en) | 2019-02-12 |
| CN109324218B true CN109324218B (en) | 2021-05-07 |
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| CN110007126B (en) * | 2019-04-17 | 2020-10-16 | 电子科技大学 | Direct current bus voltage isolation detection circuit |
| CN110542787A (en) * | 2019-07-22 | 2019-12-06 | 北京中航智科技有限公司 | voltage acquisition device for DC bus of three-level motor driver |
| CN111398655B (en) * | 2020-03-08 | 2022-12-09 | 苏州浪潮智能科技有限公司 | Input current detection circuit and method |
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| CN101187678A (en) * | 2007-11-30 | 2008-05-28 | 艾默生网络能源有限公司 | Frequency converter output voltage detection circuit |
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2017
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| CN101187678A (en) * | 2007-11-30 | 2008-05-28 | 艾默生网络能源有限公司 | Frequency converter output voltage detection circuit |
| CN102967748A (en) * | 2012-11-12 | 2013-03-13 | 宁波韵升股份有限公司 | DC bus voltage detection circuit with high antijamming capability |
| CN203164277U (en) * | 2012-12-04 | 2013-08-28 | 阳光电源股份有限公司 | Overcurrent and overvoltage protection detection circuit |
| CN203658440U (en) * | 2013-11-27 | 2014-06-18 | 深圳市伟创电气有限公司 | High-precision high voltage isolation operational amplifier detection circuit |
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