CN203278180U - Simple Electronic Backup Protection Device for AC Circuit Breaker - Google Patents

Abstract

The utility model relates to a simple electronic backup protection device for an AC circuit breaker. It includes input terminals of three current transformers, three rectifier bridges, ten resistors and electrolytic capacitors, voltage regulator tubes, operational amplifiers AR1, AR2, triode Q1 and executive magnetic flux M1; it flows through any of the three current transformers When the current of one phase or more than one phase is greater than the set short-circuit current value, the induced current is rectified by three rectifier bridges, and a negative signal is generated at its non-GND terminal through three resistors, and then enters the operational amplifier AR1 through another resistor for further processing. Inverted proportional amplification and then the output terminal of the operational amplifier AR1 is connected to the non-inverting input terminal of the operational amplifier AR2; at this time, the amplitude of the signal is greater than the reference voltage value between the other two resistors, the operational amplifier AR2 outputs a high voltage, and the magnetic flux action is performed to open the circuit device is disconnected. The circuit has simple structure, strong stability, low cost and reliable short-circuit protection function, which greatly improves the short-circuit breaking protection action time of the electronic intelligent circuit breaker.

Description

Simple Electronic Backup Protection Device for AC Circuit Breaker

technical field

The utility model belongs to an AC circuit current protection circuit, in particular to a simple electronic backup protection device for an AC circuit breaker.

Background technique

With the rapid and extensive application of electronic technology in various fields, the current protectors of AC circuits have also evolved from magnetic thermal circuit breakers to electronic intelligent circuit breakers. However, there is a common phenomenon at present: electronic intelligent circuit breakers are indeed much better than magnetothermal circuit breakers in terms of protection accuracy, but in terms of breaking protection speed of short-circuit current, electronic intelligent circuit breakers are generally slower for magnetothermal circuit breakers. The main reason is that the current signal collected in the electronic intelligent circuit breaker comes from the current transformer. This signal needs to be sampled and processed by the single-chip microcomputer before making a judgment on whether to operate. This process takes a period of time, but the magnetothermal circuit breaker does not This process is required. Because the short-circuit breaking protection time is greatly related to the breaking capacity of the circuit breaker, many electronic intelligent circuit breakers cannot completely break away from the limitation of magnetothermal protection, and often only replace thermal protection, but magnetic protection must be left. Some circuit breakers have also added corresponding electronic backup protection circuits in the design, but their structures are complex and use more electronic components. If there are more components, their stability will be relatively low, resulting in insufficient protection accuracy.

Contents of the invention

The utility model provides a simple electronic backup protection device for an AC circuit breaker with a simple structure and a small volume in order to solve the technical problems in the known technology.

The technical solution adopted by the utility model to solve the technical problems existing in the known technology is: it includes the signal input terminals of the first, second and third current transformers (CT1, CT2, CT3), and the first, second and third rectifiers Bridge (D1, D2, D3), first-tenth resistor (R1-R10), electrolytic capacitor (C1), voltage regulator tube (D4), first and second operational amplifiers (AR1, AR2), triode (Q1 ) and executive flux (M1);

One side of the signal input terminal of the first current transformer (CT1) is connected to pin 1 of the first rectifier bridge (D1), and the other side of the signal input terminal of the first current transformer (CT1) connected to pin 3 of the first rectifier bridge (D1); one side of the signal input terminal of the second current transformer (CT2) is connected to pin 1 of the second rectifier bridge (D2), and the first The other side of the signal input terminal of the second current transformer (CT2) is connected to the No. 3 pin of the second rectifier bridge (D2); one side of the signal input terminal of the third current transformer (CT3) is connected to the Pin 1 of the third rectifier bridge (D3), the other side of the signal input terminal of the third current transformer (CT3) is connected to pin 3 of the third rectifier bridge (D3); the first resistor One end of (R1) is connected to one end of the second resistor (R2) and one end of the third resistor (R3), which is the GND end of the system, and the other end of the first resistor (R1) is connected to the first Pin 4 of a rectifier bridge (D1), the other end of the second resistor (R2) is connected to pin 4 of the second rectifier bridge (D2), and the other end of the third resistor (R3) is connected to the pin 4 of the third rectifier bridge (D3); pin 2 of the first rectifier bridge (D1) and pin 2 of the second rectifier bridge (D2) and the third rectifier bridge (D3) The No. 2 pins of each are connected to one end of the fourth resistor (R4), and the other end of the fourth resistor (R4) is connected to the positive end of the electrolytic capacitor (C1), which is the VCC of the system; the first rectifier Pin 4 of the bridge (D1), pin 4 of the second rectifier bridge (D2) and pin 4 of the third rectifier bridge (D3) are all connected to one end of the seventh resistor (R7), The other terminal of the seventh resistor (R7) is connected to the negative input terminal of the first operational amplifier (AR1); the positive terminal of the electrolytic capacitor (C1) is connected to the cathode of the voltage regulator tube (D4) and the fifth resistor (R5), the other end of the fifth resistor (R5) is connected to the sixth resistor (R6) and the negative phase input terminal of the second operational amplifier (AR2); the anode of the regulator tube (D4) Connect the negative pole of the electrolytic capacitor (C1) to GND; one end of the sixth resistor (R6) is connected to the negative input terminal of the second operational amplifier (AR2), and the other end of the sixth resistor (R6) is connected to GND ; One end of the eighth resistor (R8) is connected to the negative input end of the first operational amplifier (AR1), and the other end of the eighth resistor (R8) is connected to the output of the first operational amplifier (AR1) The terminal is connected to the non-inverting input terminal of the second operational amplifier (AR2); one terminal of the ninth resistor (R9) is connected to the non-inverting input terminal of the first operational amplifier (AR1), and the ninth resistor (R9 ) is connected to GND; one end of the tenth resistor (R10) is connected to the output of the second operational amplifier (AR2), and the other end of the tenth resistor (R10) is connected to the transistor (Q1) base; the VCC pin of the first operational amplifier (AR1) is connected to the second operational amplifier (AR 2) The VCC pin of the first operational amplifier (AR1) is connected to the VCC of the system; the VSS pin of the first operational amplifier (AR1) is connected to the GND of the system; the VSS pin of the second operational amplifier (AR2) is connected to the GND of the system; one end of the execution magnetic flux (M1) Connect to VCC, the other end of the execution flux (M1) is connected to the collector of the triode (Q1); the emitter of the triode (Q1) is connected to GND.

The utility model has the advantages and positive effects: the circuit structure is simple, the stability is strong, the cost is low, the short-circuit protection function is reliable, and the action time of the short-circuit breaking protection of the electronic intelligent circuit breaker is greatly improved.

Description of drawings

Fig. 1 is the schematic circuit diagram of the utility model.

Detailed ways

In order to further understand the invention content, characteristics and effects of the present utility model, the following examples are given, and detailed descriptions are as follows in conjunction with the accompanying drawings:

As shown in Figure 1, one side of the current transformer CT1 is connected to the No. 1 pin of the rectifier bridge D1, the other side of the current transformer CT1 is connected to the No. 3 pin of the rectifier bridge D1; one side of the current transformer CT2 is connected to the rectifier bridge D2 The other side of current transformer CT2 is connected to No. 3 pin of rectifier bridge D2; one side of current transformer CT3 is connected to No. 1 pin of rectifier bridge D3, and the other side of current transformer CT3 is connected to rectifier bridge D3 One end of resistor R1 is connected to one end of resistor R2 and one end of resistor R3, which is the GND end of the system, the other end of resistor R1 is connected to pin 4 of rectifier bridge D1, and the other end of resistor R2 is connected to rectifier bridge D2 The other end of the resistor R3 is connected to the No. 4 pin of the rectifier bridge D3; the No. 2 pin of the rectifier bridge D1, the No. 2 pin of the rectifier bridge D2, and the No. 2 pin of the rectifier bridge D3 are connected to one end of the resistor R4. The other end of the resistor R4 is connected to the positive end of the electrolytic capacitor C1, which is the VCC of the system; the No. 4 pin of the rectifier bridge D1, the No. 4 pin of the rectifier bridge D2, and the No. 4 pin of the rectifier bridge D3 are all connected to one end of the resistor R7. The other end of the resistor R7 is connected to the negative phase input of the operational amplifier AR1; the positive end of the electrolytic capacitor C1 is connected to the cathode of the regulator tube D4 and one end of the resistor R5, and the other end of the resistor R5 is connected to the sixth resistor R6 and the negative input of the operational amplifier AR2. Phase input terminal; the anode of the voltage regulator tube D4 is connected to the negative pole of the electrolytic capacitor C1 to GND; one end of the resistor R6 is connected to the negative phase input terminal of the operational amplifier AR2, and the other end of the resistor R6 is connected to GND; one end of the resistor R8 is connected to the operational amplifier AR1 The negative phase input terminal, the other end of the resistor R8 is connected to the output terminal of the operational amplifier AR1 and the positive phase input terminal of the operational amplifier AR2; one end of the resistor R9 is connected to the positive phase input terminal of the operational amplifier AR1, and the other end of the resistor R9 is connected to GND; One end of R10 is connected to the output end of the operational amplifier AR2, and the other end of the resistor R10 is connected to the base of the transistor Q1; the VCC pin of the operational amplifier AR1 is connected to the VCC pin of the operational amplifier AR2 to the VCC of the system; the VSS pin of the operational amplifier AR1 is connected to the operational amplifier The VSS pin of AR2 is connected to the GND of the system; one end of the execution magnetic flux M1 is connected to VCC, and the other end of the execution magnetic flux is connected to the collector of the transistor Q1; the emitter of the transistor Q1 is connected to GND.

The working principle is: the current induced by the current transformers CT1, CT2, and CT3 is rectified by the rectifier bridges D1, D2, and D3, then passes through the resistor R4 to the positive pole of the electrolytic capacitor C1 and the cathode of the voltage regulator tube D4, and passes through the voltage regulator tube. After the voltage is stabilized, a stable DC voltage VCC is generated. After the DC voltage passes through the resistors R5 and R6, a stable voltage is generated between the resistors R5 and R6. This voltage value is connected to the negative phase input terminal of the operational amplifier AR2 as a reference value. .

Under normal circumstances, the current flowing through the current transformers CT1, CT2, and CT3 is less than the set current of the short-circuit protection, and the induced current flows through the resistors R1, R2, and R3 after being rectified by the rectifier bridge D1, D2, and D3. A negative signal is generated at the non-GND terminals of R1, R2, and R3. This negative signal enters the operational amplifier AR1 through the resistor R7 for inverse proportional amplification. The magnification factor is the ratio of the resistor R8 to R7. The output terminal is connected to the non-inverting input terminal of the operational amplifier AR2; at this time, the amplitude of the signal is smaller than the reference voltage value between the resistor R5 and the resistor R6, the output terminal of the operational amplifier AR2 outputs a low voltage, and the magnetic flux does not operate, and the circuit breaker Do not disconnect.

When the current flowing through any phase or more than one phase of the three current transformers CT1, CT2, CT3 is greater than the set short-circuit current value, the induced current is rectified by the rectifier bridge D1, D2, D3 , after flowing through the resistors R1, R2, R3, a negative signal is generated at the non-GND terminals of R1, R2, R3. This negative signal enters the operational amplifier AR1 through the resistor R7 for inverse proportional amplification. The magnification is the ratio of the resistors R8 to R7 , after inverse amplification, the output terminal of the operational amplifier AR1 is connected to the non-inverting input terminal of the operational amplifier AR2; at this time, the amplitude of the signal is greater than the reference voltage value between the resistor R5 and the resistor R6, and the output terminal of the operational amplifier AR2 outputs high voltage, the magnetic flux action is performed, and the circuit breaker opens immediately.

Claims (1)

1. easy AC circuit breaker electronic type backup protection equipment, it is characterized in that: it includes first, second and third current transformer (CT1, CT2, CT3) signal input terminal, first, second and third rectifier bridge (D1, D2, D3), first--the tenth resistance (R1-R10), electrochemical capacitor (C1), voltage-stabiliser tube (D4), first and second operational amplifier (AR1, AR2), triode (Q1) and execution magnetic flux (M1);

No. 1 pin of described the first rectifier bridge of one side joint of the signal input terminal of described the first current transformer (CT1) (D1), No. 3 pin of described the first rectifier bridge of another side joint of the signal input terminal of described the first current transformer (CT1) (D1); No. 1 pin of described the second rectifier bridge of one side joint of the signal input terminal of described the second current transformer (CT2) (D2), No. 3 pin of described the second rectifier bridge of another side joint of the signal input terminal of described the second current transformer (CT2) (D2); No. 1 pin of described the 3rd rectifier bridge of one side joint of the signal input terminal of described the 3rd current transformer (CT3) (D3), No. 3 pin of described the 3rd rectifier bridge of another side joint of the signal input terminal of described the 3rd current transformer (CT3) (D3); One end of one end of described the second resistance of one termination of described the first resistance (R1) (R2) and described the 3rd resistance (R3), GND end for native system, No. 4 pin of described the first rectifier bridge of another termination of described the first resistance (R1) (D1), No. 4 pin of described the second rectifier bridge of another termination of described the second resistance (R2) (D2), No. 4 pin of described the 3rd rectifier bridge of another termination of described the 3rd resistance (R3) (D3); No. 2 pin of No. 2 pin of described the first rectifier bridge (D1) and described the second rectifier bridge (D2) and No. 2 pin of described the 3rd rectifier bridge (D3) are all received an end of described the 4th resistance (R4), the anode of another termination electrochemical capacitor (C1) of described the 4th resistance (R4) is the VCC of native system; No. 4 pin of No. 4 pin of described the first rectifier bridge (D1) and described the second rectifier bridge (D2) and No. 4 pin of described the 3rd rectifier bridge (D3) are all received an end of described the 7th resistance (R7), the negative-phase input of described the first operational amplifier of another termination of described the 7th resistance (R7) (AR1); The negative electrode of the positive termination voltage-stabiliser tube (D4) of electrochemical capacitor (C1) and an end of described the 5th resistance (R5), the negative-phase input of described the 6th resistance of another termination of described the 5th resistance (R5) (R6) and described the second operational amplifier (AR2); The negative pole that the anode of voltage-stabiliser tube (D4) connects electrochemical capacitor (C1) meets GND; The negative-phase input of described the second operational amplifier of one termination of described the 6th resistance (R6) (AR2), another termination GND of described the 6th resistance (R6); The negative-phase input of described the first operational amplifier of one termination of described the 8th resistance (R8) (AR1), the normal phase input end of described the second operational amplifier of the output termination of described the first operational amplifier of another termination of described the 8th resistance (R8) (AR1) (AR2); The normal phase input end of described the first operational amplifier of one termination of described the 9th resistance (R9) (AR1), another termination GND of described the 9th resistance (R9); The output of described the second operational amplifier of one termination of described the tenth resistance (R10) (AR2), the base stage of the described triode of another termination (Q1) of described the tenth resistance (R10); The VCC pin of described the first operational amplifier (AR1) meets the VCC of the VCC pin welding system of described the second operational amplifier (AR2); The VSS pin of described the first operational amplifier (AR1) meets the GND of the VSS pin welding system of described the second operational amplifier (AR2); One termination VCC of described execution magnetic flux (M1), the collector electrode of the described triode of another termination of described execution magnetic flux (M1)-(Q1); The emitter of described triode (Q1) meets GND.

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