Detection circuit and detection device for minimum conduction holding current of silicon controlled rectifier

Abstract

The utility model discloses a silicon controlled rectifier minimum conduction holding current detection circuit comprising a direct current boost module connected with a 5V voltage; the voltage division feedback module is connected with the direct current boosting module, and the voltage division feedback module is used for dividing the output voltage of the direct current boosting module; the discharge sampling module is connected with the partial pressure feedback module, and the discharge sampling module is used for carrying out discharge sampling on the silicon controlled rectifier conduction current; the silicon controlled rectifier is connected with the discharge sampling module; and different pins of the single-chip microcomputer are respectively connected with the direct-current boosting module, the partial pressure feedback module and the discharge sampling module, and the single-chip microcomputer is used for controlling the conduction current of the silicon controlled rectifier and carrying out sampling judgment on the conduction current.

Description

Technical Field

[0001] The utility model relates to the field of electronic technology, in particular to a minimum conduction maintaining current detection circuit and a detection device of a thyristor. Background Art

[0002] SCR is a high-power electrical component, also known as thyristor. As the use time increases, the internal electronic structure of the thyristor will gradually age, and eventually fail and short-circuit, which is reflected in the limited service life of the thyristor. Among them, thyristors are divided into unidirectional thyristors and bidirectional thyristors. Generally, the current use of thyristors mostly refers to the use of unidirectional thyristors.

[0003] In the prior art, in order to evaluate the parameter deviation problem during the aging process of the thyristor, the minimum on-state holding current of the thyristor is usually detected.

[0004] However, the applicant has found through research that the device currently available on the market for detecting the minimum on-state holding current of a thyristor is relatively complex in structure and has a relatively high cost. Utility Model Content

[0005] In order to overcome the above technical defects, the utility model provides a minimum on-state maintaining current detection circuit of a thyristor.

[0006] In order to solve the above problems, the utility model is implemented according to the following technical solutions:

[0007] In a first aspect, the utility model provides a minimum on-state holding current detection circuit of a thyristor, the detection circuit comprising:

[0008] A DC boost module, wherein the DC boost module is connected to a 5V voltage;

[0009] A voltage division feedback module, the voltage division feedback module and the DC boost module, the voltage division feedback module is used to divide the output voltage of the DC boost module;

[0010] A discharge sampling module, the discharge sampling module is connected to the voltage division feedback module, and the discharge sampling module is used to perform discharge sampling on the thyristor conduction current;

[0011] A thyristor, the thyristor is connected to the discharge sampling module;

[0012] A single-chip microcomputer, wherein different pins of the single-chip microcomputer are respectively connected to the DC boost module, the voltage divider feedback module, and the discharge sampling module. The single-chip microcomputer is used to control the conduction current of the thyristor and to sample and judge the conduction current.

[0013] Preferably, the DC boost module includes a first capacitor, a first inductor, a first resistor, a first MOS tube, a diode and a second capacitor;

[0014] One end of the first capacitor is connected to a 5V voltage and the first inductor, and the other end is connected to the first resistor and the source of the first MOS tube;

[0015] One end of the first inductor is connected to the first capacitor, and the other end is connected to the drain of the first MOS tube and the diode;

[0016] One end of the first resistor is connected to the first capacitor, and the other end is connected to the gate of the first MOS transistor;

[0017] The gate of the first MOS tube is connected to pin 32 of the single chip computer;

[0018] The anode of the diode is connected to the drain of the first MOS tube and the first inductor, and the cathode of the diode is connected to the second capacitor;

[0019] One end of the second capacitor is connected to the cathode of the diode and the voltage-dividing feedback module, and the other end is connected to the source of the first MOS tube and the voltage-dividing feedback module;

[0020] The source of the first MOS tube is grounded, the drain is connected to the first inductor and the positive electrode of the diode, and the gate is connected to the first resistor and the 32nd pin of the single chip computer.

[0021] Preferably, the voltage-dividing feedback module comprises a seventh resistor and an eighth resistor;

[0022] One end of the seventh resistor is connected to the second capacitor in the DC boost module, and the other end is connected to the eighth resistor;

[0023] One end of the eighth resistor is connected to the seventh resistor and the pin 13 of the single chip microcomputer, and the other end is connected to the second capacitor in the DC boost module.

[0024] Preferably, the discharge sampling module includes a second resistor, a third resistor and a second MOS tube;

[0025] One end of the second resistor is connected to the seventh resistor, and the other end is connected to the drain of the second MOS tube;

[0026] One end of the third resistor is connected to the eighth resistor and the source of the second MOS transistor, and the other end is connected to the gate of the second MOS transistor;

[0027] The gate of the second MOS tube is connected to the 45th pin of the single chip computer.

[0028] Preferably, the discharge sampling module further includes a fourth resistor, a fifth resistor, a sixth resistor and a triode;

[0029] One end of the fourth resistor is connected to a 5V voltage and the sixth resistor, and the other end is connected to the transistor;

[0030] One end of the sixth resistor is connected to the fourth resistor, and the other end is connected to the triode and the thyristor;

[0031] The collector of the transistor is connected to the sixth resistor, the emitter is grounded, and the base is connected to the fourth resistor and the 46th pin of the single chip microcomputer;

[0032] One end of the fifth resistor is connected to the thyristor and the 12th pin of the single chip microcomputer, and the other end is connected to the emitter of the transistor.

[0033] Preferably, the gate of the thyristor is connected to the sixth resistor and the transistor, the anode is connected to the second resistor and the drain of the second MOS tube, and the cathode is connected to the fifth resistor.

[0034] Preferably, the single chip microcomputer is an STM32 single chip microcomputer.

[0035] On the other hand, the utility model further provides a thyristor minimum on-state maintaining current detection device, comprising a thyristor minimum on-state maintaining current detection circuit according to the first aspect.

[0036] Compared with the prior art, the utility model has the following beneficial effects: the present invention adopts a DC boost circuit topology structure, and realizes the boost and continuous adjustment of the output DC voltage by controlling the modulation pulse through the STM32 single-chip microcomputer. And by synchronously triggering the thyristor to turn on and the single-chip microcomputer sampling and recording the current flowing through the thyristor until the thyristor is cut off, the minimum holding current of the thyristor can be obtained. In the circuit of the present invention, the current of the thyristor is gradually attenuated from large to the thyristor cut-off, which is more in line with the current change trend of the thyristor under actual use. The overall detection circuit structure is simpler, which reduces the detection cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The specific implementation of the utility model is further described in detail below with reference to the accompanying drawings, wherein:

[0038] Figure 1 This is a circuit connection principle diagram of a minimum conduction maintaining current detection circuit of a thyristor of the utility model;

[0039] Figure 2 It is a structural schematic diagram of the STM32 single-chip microcomputer of the utility model. DETAILED DESCRIPTION

[0040] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0041] like Figure 1 As shown, the preferred structure of the minimum on-state holding current detection circuit of a thyristor described in the utility model.

[0042] See also Figure 1 , the utility model provides a technical solution:

[0043] A minimum conduction maintaining current detection circuit for a thyristor, the detection circuit comprising: a DC boost module, the DC boost module is connected to a 5V voltage; a voltage division feedback module, the voltage division feedback module and the DC boost module, the voltage division feedback module is used to divide the output voltage of the DC boost module; a discharge sampling module, the discharge sampling module is connected to the voltage division feedback module, the discharge sampling module is used to perform discharge sampling on the conduction current of the thyristor; thyristor, the thyristor is connected to the discharge sampling module; a single-chip microcomputer, different pins of the single-chip microcomputer are respectively connected to the DC boost module, the voltage division feedback module, and the discharge sampling module, the single-chip microcomputer is used to control the conduction current of the thyristor and sample and judge the conduction current.

[0044] In a specific embodiment, a thyristor minimum conduction maintaining current detection circuit is composed of a DC boost module, a voltage divider feedback module, a discharge sampling module, a thyristor and a single chip. The single chip modulates the output voltage of the DC boost module, samples and judges the voltage after the voltage divider feedback module divides and reduces the voltage, continues to convert the current flowing through the thyristor in the discharge sampling module into a voltage sample, and finally judges the minimum conduction maintaining current of the thyristor.

[0045] Preferably, the DC boost module includes a first capacitor, a first inductor, a first resistor, a first MOS tube, a diode and a second capacitor.

[0046] One end of the first capacitor is connected to a 5V voltage and the first inductor, and the other end is connected to the first resistor and the source of the first MOS tube.

[0047] One end of the first inductor is connected to the first capacitor, and the other end is connected to the drain of the first MOS tube and the diode.

[0048] One end of the first resistor is connected to the first capacitor, and the other end is connected to the gate of the first MOS tube.

[0049] The gate of the first MOS tube is connected to pin 32 of the microcontroller.

[0050] The anode of the diode is connected to the drain of the first MOS tube and the first inductor, and the cathode of the diode is connected to the second capacitor.

[0051] One end of the second capacitor is connected to the cathode of the diode and the voltage-dividing feedback module, and the other end is connected to the source of the first MOS tube and the voltage-dividing feedback module.

[0052] The source of the first MOS tube is grounded, the drain is connected to the first inductor and the positive electrode of the diode, and the gate is connected to the first resistor and the 32nd pin of the single chip computer.

[0053] like Figure 1 As shown, the DC boost module includes a first capacitor C1, a first inductor L1, a first resistor R1, a first MOS transistor Q1, a diode D1 and a second capacitor C2.

[0054] Specifically, the connection method is: one end of C1 is connected to a 5V voltage and to one end of L1, and the other end of C1 is connected to the source of R1 and Q1; the other end of L1 is connected to the positive electrode (anode) of D1 and the drain of Q1; Figure 2 As shown, the gate (control end) of Q1 is connected to R1 and the 32-pin G2 of the microcontroller; the negative electrode (cathode) of D1 is connected to one end of C2; and the other end of C2 is connected to Q1.

[0055] In a specific embodiment, the first MOS tube constitutes an electronic switch, also referred to as the first electronic switch. The control terminal (gate) of Q1 is controlled by the 32-pin G1 of the STM32 single-chip microcomputer. The inductor L1, the diode D1, the capacitor C2 and the electronic switch (first MOS tube) Q1 constitute a DC boost control circuit. By adjusting the duty cycle of the 32-pin of the single-chip microcomputer, the voltage across C2 can be adjusted to about 20V. Among them, C1 is a filter capacitor for improving the anti-interference performance of the circuit, and R1 is the gate (gate) protection resistor of Q1.

[0056] Preferably, the voltage-dividing feedback module comprises a seventh resistor and an eighth resistor.

[0057] One end of the seventh resistor is connected to the second capacitor in the DC boost module, and the other end is connected to the eighth resistor.

[0058] One end of the eighth resistor is connected to the seventh resistor and the pin 13 of the single chip microcomputer, and the other end is connected to the second capacitor in the DC boost module.

[0059] like Figure 1 As shown, the voltage-dividing feedback module includes a seventh resistor R7 and an eighth resistor R8.

[0060] Specifically, one end of R7 is connected to one end of C2 in the DC boost module, and the other end is connected to R8; one end of R8 is connected to R7 and pin 13 U of the microcontroller, and the other end is connected to the other end of C2.

[0061] In a specific embodiment, the resistors R7 and R8 form a voltage-dividing feedback circuit, which divides and reduces the voltage across C2 and provides it to the single-chip microcomputer for sampling and judgment.

[0062] Preferably, the discharge sampling module includes a second resistor, a third resistor and a second MOS tube.

[0063] One end of the second resistor is connected to the seventh resistor, and the other end is connected to the drain of the second MOS tube.

[0064] One end of the third resistor is connected to the eighth resistor and the source of the second MOS tube, and the other end is connected to the gate of the second MOS tube.

[0065] The gate of the second MOS tube is connected to pin 45 of the microcontroller.

[0066] like Figure 1 As shown, the discharge sampling module includes a second resistor R2, a third resistor R3 and a second MOS tube Q2.

[0067] Specifically, one end of R2 is connected to R7 and C2, and the other end is connected to the drain of Q2 and the anode of the thyristor SCR; one end of R3 is connected to the source of Q2 and R8, and the other end is connected to the gate (control end) of Q2. Figure 2 As shown, the gate (control terminal) of Q2 is connected to the 45-pin G2 of the microcontroller.

[0068] In a specific embodiment, the second MOS tube also becomes the second electronic switch. When the circuit is just powered on, the 45th pin of the single chip microcomputer outputs a high level, so that Q2 is turned on, and the thyristor SCR is prevented from being turned on during the power-on process. Among them, R3 is the gate protection resistor of Q2.

[0069] Preferably, the discharge sampling module further includes a fourth resistor, a fifth resistor, a sixth resistor and a triode.

[0070] One end of the fourth resistor is connected to a 5V voltage and the sixth resistor, and the other end is connected to the transistor.

[0071] One end of the sixth resistor is connected to the fourth resistor, and the other end is connected to the triode and the thyristor.

[0072] The collector of the transistor is connected to the sixth resistor, the emitter is grounded, and the base is connected to the fourth resistor and the 46th pin of the single chip computer.

[0073] One end of the fifth resistor is connected to the thyristor and the 12th pin of the single chip computer, and the other end is connected to the emitter of the transistor.

[0074] like Figure 1 As shown, the discharge sampling module further includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a transistor Q3.

[0075] Specifically, one end of R4 is connected to a 5V voltage and R6, and the other end is connected to Q3; one end of R6 is connected to R4, and the other end is connected to Q3 and the gate of the thyristor; Figure 2 As shown, the collector of Q3 is connected to R6, the emitter is grounded, and the base is connected to R4 and the 46-pin G3 of the microcontroller; one end of R5 is connected to the cathode of the thyristor and the 12-pin 1 of the microcontroller, and the other end is connected to the emitter of Q3.

[0076] In a specific embodiment, Q3 is an NPN transistor. When the circuit is just powered on, Q3 is turned on, and there is no trigger voltage on the gate of the thyristor SCR, ensuring that the thyristor is in the off state. Resistor R5 converts the current flowing through the thyristor into a voltage for sampling and calculation by the microcontroller to obtain an accurate thyristor current value. Among them, R4 and R6 are current limiting resistors of Q3.

[0077] Preferably, the gate of the thyristor is connected to the sixth resistor and the transistor, the anode is connected to the second resistor and the drain of the second MOS tube, and the cathode is connected to the fifth resistor.

[0078] Preferably, the single chip microcomputer is an STM32 single chip microcomputer.

[0079] like Figure 2 As shown, the single-chip microcomputer is the STM single-chip microcomputer U1.

[0080] In a specific embodiment, after the circuit starts measuring, the single-chip microcomputer U1 controls G1 so that the voltage across C2 gradually rises to about 20V. At this time, the single-chip microcomputer U1 controls the 46-pin to output a low-level voltage, and the gate of the thyristor SCR obtains a trigger current through the resistor R6 to achieve trigger conduction. After the thyristor is triggered and turned on, the voltage across C2 forms a discharge circuit through the resistor R2, the thyristor SCR and the resistor R5. The voltage across C2 gradually decreases, and the current flowing through the thyristor SCR also gradually decreases. When the current flowing through the thyristor SCR is less than the minimum conduction maintaining current, the thyristor SCR is turned off and the voltage across the resistor R5 returns to zero. By sampling the voltage across R5 during the discharge process, the minimum current passing through the thyristor SCR before it is turned off can be obtained, and the minimum conduction maintaining current value of the thyristor SCR can be obtained.

[0081] The present invention adopts a DC boost circuit topology structure, and realizes the boost and continuous adjustment of the output DC voltage by controlling the modulation pulse through the STM32 single-chip microcomputer. And by synchronously triggering the thyristor to turn on and the single-chip microcomputer sampling and recording the current flowing through the thyristor until the thyristor is cut off, the minimum holding current of the thyristor can be obtained. In the circuit of the present invention, the current of the thyristor is gradually attenuated from large to the thyristor cut-off, which is more in line with the current change trend of the thyristor in actual use. The overall detection circuit structure is simpler, which reduces the detection cost.

[0082] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Therefore, any modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A minimum conduction holding current detection circuit for a thyristor, characterized in that: The detection circuit comprises: A DC boost module, wherein the DC boost module is connected to a 5V voltage; A voltage division feedback module, the voltage division feedback module and the DC boost module, the voltage division feedback module is used to divide the output voltage of the DC boost module; A discharge sampling module, the discharge sampling module is connected to the voltage division feedback module, and the discharge sampling module is used to perform discharge sampling on the thyristor conduction current; A thyristor, the thyristor is connected to the discharge sampling module; A single-chip microcomputer, wherein different pins of the single-chip microcomputer are respectively connected to the DC boost module, the voltage divider feedback module, and the discharge sampling module. The single-chip microcomputer is used to control the conduction current of the thyristor and to sample and judge the conduction current.

2. The minimum on-state holding current detection circuit of a thyristor according to claim 1, characterized in that: The DC boost module includes a first capacitor, a first inductor, a first resistor, a first MOS tube, a diode and a second capacitor; One end of the first capacitor is connected to a 5V voltage and the first inductor, and the other end is connected to the first resistor and the source of the first MOS tube; One end of the first inductor is connected to the first capacitor, and the other end is connected to the drain of the first MOS tube and the diode; One end of the first resistor is connected to the first capacitor, and the other end is connected to the gate of the first MOS transistor; The gate of the first MOS tube is connected to pin 32 of the single chip computer; The anode of the diode is connected to the drain of the first MOS tube and the first inductor, and the cathode of the diode is connected to the second capacitor; One end of the second capacitor is connected to the cathode of the diode and the voltage-dividing feedback module, and the other end is connected to the source of the first MOS tube and the voltage-dividing feedback module; The source of the first MOS tube is grounded, the drain is connected to the first inductor and the positive electrode of the diode, and the gate is connected to the first resistor and the 32nd pin of the single chip computer.

3. The minimum on-state holding current detection circuit of a thyristor according to claim 2, characterized in that: The voltage division feedback module includes a seventh resistor and an eighth resistor; One end of the seventh resistor is connected to the second capacitor in the DC boost module, and the other end is connected to the eighth resistor; One end of the eighth resistor is connected to the seventh resistor and the pin 13 of the single chip microcomputer, and the other end is connected to the second capacitor in the DC boost module.

4. The minimum on-state holding current detection circuit of a thyristor according to claim 3, characterized in that: The discharge sampling module includes a second resistor, a third resistor and a second MOS tube; One end of the second resistor is connected to the seventh resistor, and the other end is connected to the drain of the second MOS tube; One end of the third resistor is connected to the eighth resistor and the source of the second MOS transistor, and the other end is connected to the gate of the second MOS transistor; The gate of the second MOS tube is connected to the 45th pin of the single chip computer.

5. The minimum on-state holding current detection circuit of a thyristor according to claim 4, characterized in that: The discharge sampling module also includes a fourth resistor, a fifth resistor, a sixth resistor and a triode; One end of the fourth resistor is connected to a 5V voltage and the sixth resistor, and the other end is connected to the transistor; One end of the sixth resistor is connected to the fourth resistor, and the other end is connected to the triode and the thyristor; The collector of the transistor is connected to the sixth resistor, the emitter is grounded, and the base is connected to the fourth resistor and the 46th pin of the single chip microcomputer; One end of the fifth resistor is connected to the thyristor and the 12th pin of the single chip microcomputer, and the other end is connected to the emitter of the transistor.

6. The minimum on-state holding current detection circuit of a thyristor according to claim 5, characterized in that: The gate of the thyristor is connected to the sixth resistor and the transistor, the anode is connected to the second resistor and the drain of the second MOS tube, and the cathode is connected to the fifth resistor.

7. The minimum on-state holding current detection circuit of a thyristor according to claim 6, characterized in that: The single chip microcomputer is an STM32 single chip microcomputer.

8. A device for detecting the minimum on-state current of a thyristor, characterized in that: A minimum on-state maintaining current detection circuit for a thyristor comprising the circuit described in any one of claims 1 to 7.

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