Excitation voltage detection circuit and detection device of exciter

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By designing the excitation voltage detection circuit of the excitation machine, using transformer isolation, rectifier circuit conversion, filter filter removal and microcontroller sampling and calculation, the problem of lack of excitation voltage detection devices in the prior art is solved, accurate detection and control of the excitation voltage is achieved, and the control accuracy of the excitation system is improved.

CN222599741UActive Publication Date: 2025-03-11SICHUAN DATANG INT GANZI HYDROELECTRIC DEV CO LTD +1

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Patent Information

Application Number: CN202323602594.7
Authority / Receiving Office: CN · China
Patent Type: Utility models(China)
Current Assignee / Owner
Filing Date: 2023-12-28
Publication Date: 2025-03-11
Estimated Expiration: 2033-12-28

AI Technical Summary

Technical Problem

The prior art lacks a detection device for excitation voltage of the excitation machine, which leads to the inability to monitor and control the excitation voltage in real time, affecting the control accuracy of the excitation system.

Method used

An excitation voltage detection circuit for an exciter is designed, including an input module, a rectifier module, a follow-up filter module, an amplification filter module and a microcontroller. Through transformer isolation and step-down, rectification circuit conversion, filter filter removal and microcontroller sampling calculation, the input three-phase AC voltage value is accurately obtained.

Benefits of technology

Accurate detection and control of excitation voltage is realized, the control accuracy of the excitation system is improved, and the stability and safety of the system are ensured.

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Abstract

The utility model discloses an excitation voltage detection circuit of an exciter. The excitation voltage detection circuit comprises an input module, a rectification module, a following filtering module, an amplification filtering module and a single-chip microcomputer. The input module comprises a transformer and an input three-phase alternating current voltage, the input three-phase alternating current voltage is connected with the transformer, and the transformer converts the input three-phase alternating current voltage into a low-voltage current signal; the rectification module comprises a rectification circuit and a first resistor, the rectification module is connected with the input module, and the low-voltage current signal is rectified by the rectification circuit and then converted into a voltage signal by the first resistor; the following filtering module is connected with the rectifying module and comprises a voltage follower and a first low-pass filter; the amplifying and filtering module is connected with the following filtering module and comprises an in-phase amplifier and a second low-pass filter; the single-chip microcomputer is connected with the amplification filtering module. A voltage signal flows through the following filtering module and the amplification filtering module, and an input three-phase AC voltage value can be obtained through internal sampling calculation and conversion of the single-chip microcomputer.

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Description

Technical Field

[0001] The utility model relates to the field of excitation systems, in particular to an excitation voltage detection circuit and a detection device for an excitation machine. Background Art

[0002] AC brushless excitation synchronous motors are widely used in mining, chemical industry and other places where synchronous motors are needed and sparks and other explosive factors cannot be generated. The armature winding and excitation winding of the AC brushless excitation synchronous motor are both three-phase AC windings. The excitation winding of the excitation machine (generally called the stator winding of the excitation machine) is output by the external three-phase AC voltage regulation circuit. The chopped AC excitation voltage is output by the excitation machine excitation winding (generally called the excitation machine stator winding), and then a rotating magnetic field is generated, and an induced voltage is generated in the armature winding of the excitation machine (generally called the rotor winding of the excitation machine). The induced voltage of the armature winding of the excitation machine is rectified into a DC voltage by a rotating rectifier and supplied to the excitation winding of the main motor to realize excitation, but there is currently a lack of detection devices for the excitation voltage of the excitation machine. Utility Model Content

[0003] In order to overcome the above technical defects, the utility model provides an excitation voltage detection circuit and a detection device for an exciter. In order to solve the above problems, the utility model is implemented according to the following technical solutions:

[0004] In the first aspect, the utility model provides an excitation voltage detection circuit of an excitation machine, the excitation voltage detection circuit comprising: an input module, a rectifier module, a follower filter module, an amplifying filter module and a single-chip microcomputer; the input module comprises a transformer and an input three-phase AC voltage, the input three-phase AC voltage is connected to the transformer, and the transformer converts the input three-phase AC voltage into a low-voltage current signal; the rectifier module comprises a rectifier circuit and a first resistor, the rectifier module is connected to the input module, and the low-voltage current signal is rectified by the rectifier circuit and then converted into a voltage signal by the first resistor; the follower filter module is connected to the rectifier module, and the follower filter module comprises a voltage follower and a first low-pass filter; the amplifying filter module is connected to the follower filter module, and the amplifying filter module comprises a common-phase amplifier and a second low-pass filter; the single-chip microcomputer is connected to the amplifying filter module; the voltage signal flows through the follower filter module and the amplifying filter module, and the input three-phase AC voltage value can be obtained through sampling, calculation and conversion inside the single-chip microcomputer.

[0005] In combination with the first aspect, further, the input three-phase AC voltage includes a first voltage, a second voltage and a third voltage;

[0006] The transformer includes a first transformer, a second transformer and a third transformer;

[0007] Pin 1 of the first transformer is connected to the first voltage, and pin 2 of the first transformer is connected to the second voltage;

[0008] Pin 1 of the second transformer is connected to the second voltage, and pin 2 of the second transformer is connected to the third voltage;

[0009] Pin 1 of the third transformer is connected to the third voltage, and pin 2 of the third transformer is connected to the first voltage.

[0010] In combination with the first aspect, further, the input module further includes a second resistor, a third resistor and a fourth resistor;

[0011] One end of the second resistor is connected to the first voltage, and the other end of the second resistor is connected to pin 1 of the first transformer;

[0012] One end of the third resistor is connected to the second voltage, and the other end of the third resistor is connected to pin 1 of the second transformer;

[0013] One end of the fourth resistor is connected to the third voltage, and the other end of the fourth resistor is connected to pin 1 of the third transformer.

[0014] In combination with the first aspect, further, the rectifier circuit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth diode, a seventh diode and an eighth diode;

[0015] The anode of the first diode is connected to the cathode of the fifth diode;

[0016] The anode of the second diode is connected to the cathode of the sixth diode;

[0017] The anode of the third diode is connected to the cathode of the seventh diode;

[0018] The anode of the fourth diode is connected to the cathode of the eighth diode;

[0019] The cathodes of the first diode, the second diode, the third diode and the fourth diode are all connected together;

[0020] The anodes of the fifth diode, the sixth diode, the seventh diode and the eighth diode are connected together and grounded;

[0021] Pin 4 of the first transformer is connected to the anode of the first diode and the cathode of the fifth diode;

[0022] Pin 4 of the second transformer is connected to the anode of the second diode and the cathode of the sixth diode;

[0023] Pin 4 of the third transformer is connected to the anode of the third diode and the cathode of the seventh diode;

[0024] The 3 pins of the first transformer, the second transformer and the third transformer are all connected to the anode of the fourth diode and the cathode of the eighth diode;

[0025] One end of the first resistor is connected to the anodes of the fifth diode, the sixth diode, the seventh diode and the eighth diode and is grounded, and the other end of the first resistor is connected to the cathodes of the first diode, the second diode, the third diode, the fourth diode and the follower filter module.

[0026] In combination with the first aspect, further, the voltage follower includes a first operational amplifier, a fifth resistor and a sixth resistor;

[0027] The first low-pass filter includes a seventh resistor and a first capacitor.

[0028] In combination with the first aspect, further, pin 3 of the first operational amplifier is connected to the first resistor; pin 4 of the first operational amplifier is grounded; pin 2 of the first operational amplifier is connected to one end of the sixth resistor; pin 6 of the first operational amplifier is connected to the other end of the sixth resistor and the seventh resistor; pin 7 of the first operational amplifier is connected to the first power supply voltage;

[0029] One end of the fifth resistor is connected to the first resistor in the rectifier module, and the other end of the fifth resistor is connected to pin 3 of the first operational amplifier;

[0030] One end of the sixth resistor is connected to pin 2 of the first operational amplifier, and the other end of the sixth resistor is connected to pin 6 of the first operational amplifier and the seventh resistor;

[0031] One end of the seventh resistor is connected to the sixth resistor and the 6th pin of the first operational amplifier, and the other end of the seventh resistor is connected to the first capacitor and the amplification and filtering module;

[0032] One end of the first capacitor is connected to the seventh resistor and the amplifying and filtering module, and the other end of the first capacitor is grounded.

[0033] In combination with the first aspect, further, the in-phase amplifier includes a second operational amplifier, an eighth resistor and a ninth resistor;

[0034] The second low pass filter includes a tenth resistor and a second capacitor.

[0035] In combination with the first aspect, further, pin 2 of the second operational amplifier is connected to the eighth resistor and the ninth resistor; pin 3 of the second operational amplifier is connected to the seventh resistor and the first capacitor in the follower filter module; pin 4 of the second operational amplifier is grounded; pin 6 of the second operational amplifier is connected to the ninth resistor and the tenth resistor; pin 7 of the second operational amplifier is connected to the second supply voltage;

[0036] One end of the eighth resistor is connected to pin 2 of the second operational amplifier, and the other end of the eighth resistor is grounded;

[0037] One end of the ninth resistor is connected to the eighth resistor and the second operational amplifier's 2 pin, and the other end of the ninth resistor is connected to the second operational amplifier's 6 pin and the tenth resistor;

[0038] One end of the tenth resistor is connected to the pin 6 of the second operational amplifier and the ninth resistor, and the other end of the tenth resistor is connected to the second capacitor and the single-chip microcomputer;

[0039] One end of the second capacitor is connected to the tenth resistor and the single chip microcomputer, and the other end of the second capacitor is grounded.

[0040] In combination with the first aspect, further, the single chip microcomputer is an STM32 single chip microcomputer, and the second low-pass filter in the amplification and filtering module is connected to pin 10 of the single chip microcomputer.

[0041] In a second aspect, an excitation voltage detection device for an exciter is provided, wherein the excitation voltage detection device comprises an excitation voltage detection circuit for an exciter as described in any one of the above.

[0042] Compared with the prior art, the excitation voltage detection circuit and detection device of the exciter described in the utility model have the following beneficial effects:

[0043] An excitation voltage detection circuit for an exciter, the excitation voltage detection circuit comprising: an input module, a rectifier module, a follower filter module, an amplifying filter module and a single-chip microcomputer; the input module comprises a transformer and an input three-phase AC voltage, the input three-phase AC voltage is connected to the transformer, and the transformer converts the input three-phase AC voltage into a low-voltage current signal; the rectifier module comprises a rectifier circuit and a first resistor, the rectifier module is connected to the input module, and the low-voltage current signal is rectified by the rectifier circuit and then converted into a voltage signal by the first resistor; the follower filter module is connected to the rectifier module, and the follower filter module comprises a voltage follower and a first low-pass filter; the amplifying filter module is connected to the follower filter module, and the amplifying filter module comprises a common-phase amplifier and a second low-pass filter; the single-chip microcomputer is connected to the amplifying filter module; the voltage signal flows through the follower filter module and the amplifying filter module, and the input three-phase AC voltage value can be obtained through sampling, calculation and conversion inside the single-chip microcomputer.

[0044] The utility model isolates, shapes, filters and samples the excitation voltage of the AC brushless excitation system, and accurately obtains the effective value of the input AC voltage by extracting the DC voltage component after signal processing, which can improve the control accuracy of this type of excitation system; the utility model uses an electronic transformer to isolate and step down the voltage to achieve strong and weak electricity isolation, and realizes AC and DC signal conversion through a diode rectifier circuit, and then filters out the high-frequency AC component superimposed in the DC voltage through an anti-aliasing filter, and finally obtains a DC voltage signal proportional to the input AC voltage through single-chip sampling and calculation. The excitation voltage detection circuit and detection device of the excitation machine provided by the utility model have simple components and convenient connection. The DC voltage value corresponding to the input voltage can be obtained through internal sampling and calculation of the single-chip microcomputer, and the AC voltage value corresponding to the input voltage can be obtained through proportional conversion, and the effective value of the input AC voltage can be accurately obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The specific implementation of the utility model is further described in detail below with reference to the accompanying drawings, wherein:

[0046] Figure 1 It is a principle structure diagram of an excitation voltage detection circuit of an exciter in the utility model;

[0047] Figure 2 It is a circuit connection diagram of an excitation voltage detection circuit of an exciter in the utility model;

[0048] In the figure:

[0049] 10-input module; 20-rectifier module; 21-rectifier circuit; 30-follower filter module; 31-voltage follower;

[0050] 32-first low-pass filter; 33-first power supply voltage; 40-amplification filter module; 41-common-phase amplifier;

[0051] 42 - a second low-pass filter; 43 - a second power supply voltage; 50 - a single-chip microcomputer. DETAILED DESCRIPTION

[0052] 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. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0053] like Figure 1-2 As shown, a preferred implementation of an excitation voltage detection circuit and a detection device for an exciter described in the utility model.

[0054] Combination Figure 1 and Figure 2 , an excitation voltage detection circuit of an exciter, comprising: an input module 10, a rectifier module 20, a follower filter module 30, an amplifying filter module and a single chip microcomputer 50; the input module 10 comprises a transformer and an input three-phase AC voltage, the input three-phase AC voltage is connected to the transformer, and the transformer converts the input three-phase AC voltage into a low-voltage current signal; the rectifier module 20 comprises a rectifier circuit 21 and a first resistor R1, the rectifier module 20 is connected to the input module 10, the low-voltage current signal is rectified by the rectifier circuit 21 and then converted into a voltage signal by the first resistor R1; the follower filter module 30 is connected to the rectifier module 20, the follower filter module 30 comprises a voltage follower 31 and a first low-pass filter 32; the amplifying filter module is connected to the follower filter module 30, the amplifying filter module comprises a common-phase amplifier 41 and a second low-pass filter 42; the single chip microcomputer 50 is connected to the amplifying filter module; the voltage signal flows through the follower filter module 30 and the amplifying filter module, and the input three-phase AC voltage value can be obtained through internal sampling, calculation and conversion of the single chip microcomputer 50.

[0055] The utility model uses a transformer isolation and voltage reduction method to achieve strong and weak electricity isolation, realizes AC / DC signal conversion through a diode rectifier circuit 21, and then uses an anti-aliasing filter to filter out the high-frequency AC component superimposed in the DC voltage, and finally obtains a DC voltage signal proportional to the input AC voltage through sampling and calculation by a single-chip microcomputer 50.

[0056] Further, the input three-phase AC voltage includes a first voltage UA, a second voltage UB and a third voltage UC;

[0057] The transformer includes a first transformer TV1, a second transformer TV2 and a third transformer TV3; pin 1 of the first transformer TV1 is connected to the first voltage UA, and pin 2 of the first transformer TV1 is connected to the second voltage; pin 1 of the second transformer TV2 is connected to the second voltage, and pin 2 of the second transformer TV2 is connected to the third voltage; pin 1 of the third transformer TV3 is connected to the third voltage, and pin 2 of the third transformer TV3 is connected to the first voltage UA.

[0058] Furthermore, the input module 10 further includes a second resistor R2, a third resistor R3 and a fourth resistor R4; one end of the second resistor R2 is connected to the first voltage UA, and the other end of the second resistor R2 is connected to pin 1 of the first transformer TV1; one end of the third resistor R3 is connected to the second voltage, and the other end of the third resistor R3 is connected to pin 1 of the second transformer TV2; one end of the fourth resistor R4 is connected to the third voltage, and the other end of the fourth resistor R4 is connected to pin 1 of the third transformer TV3. The second resistor R2, the third resistor R3 and the fourth resistor R4 are all current limiting resistors.

[0059] The transformer isolates the input high voltage and converts it into a low voltage and low current signal for subsequent electronic circuit processing.

[0060] Further, the rectifier circuit 21 includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode, a seventh diode D7 and an eighth diode D8;

[0061] The anode of the first diode D1 is connected to the cathode of the fifth diode D5;

[0062] The anode of the second diode D2 is connected to the cathode of the sixth diode D6;

[0063] The anode of the third diode D3 is connected to the cathode of the seventh diode D7;

[0064] The anode of the fourth diode D4 is connected to the cathode of the eighth diode D8;

[0065] The cathodes of the first diode D1, the second diode D2, the third diode D3 and the fourth diode D4 are all connected together;

[0066] Anodes of the fifth diode D5, the sixth diode D6, the seventh diode D7 and the eighth diode D8 are connected together and grounded;

[0067] Pin 4 of the first transformer TV1 is connected to the anode of the first diode D1 and the cathode of the fifth diode D5;

[0068] Pin 4 of the second transformer TV2 is connected to the anode of the second diode D2 and the cathode of the sixth diode D6;

[0069] Pin 4 of the third transformer TV3 is connected to the anode of the third diode D3 and the cathode of the seventh diode D7;

[0070] The 3 pins of the first transformer TV1, the second transformer TV2 and the third transformer TV3 are all connected to the anode of the fourth diode D4 and the cathode of the eighth diode D8;

[0071] One end of the first resistor R1 is connected to the anodes of the fifth diode D5, the sixth diode D6, the seventh diode D7 and the eighth diode D8 and is grounded, and the other end of the first resistor R1 is connected to the cathodes of the first diode D1, the second diode D2, the third diode D3, the fourth diode D4 and the follower filter module 30.

[0072] The eight diodes form a bridge rectifier circuit 21 to convert the AC current into a DC current, and the first resistor R1 converts the rectified current signal into a voltage signal Ug.

[0073] Furthermore, the voltage follower 31 includes a first operational amplifier U1, a fifth resistor R5 and a sixth resistor R6; the first low-pass filter 32 includes a seventh resistor R7 and a first capacitor C1. The voltage follower 31 follows and amplifies the voltage signal Ug to improve the load carrying capacity of the voltage signal Ug; the first low-pass filter 32 filters out the high-frequency AC component of the voltage signal Ug.

[0074] Further, the pin 3 of the first operational amplifier U1 is connected to the fifth resistor R5; the pin 4 of the first operational amplifier U1 is grounded; the pin 2 of the first operational amplifier U1 is connected to one end of the sixth resistor R6; the pin 6 of the first operational amplifier U1 is connected to the other end of the sixth resistor R6 and the seventh resistor R7; the pin 7 of the first operational amplifier U1 is connected to the first power supply voltage 33; the first power supply voltage 33 is 12V;

[0075] One end of the fifth resistor R5 is connected to the first resistor R1 in the rectifier module 20, and the other end of the fifth resistor R5 is connected to the 3-pin of the first operational amplifier U1;

[0076] One end of the sixth resistor R6 is connected to the pin 2 of the first operational amplifier U1, and the other end of the sixth resistor R6 is connected to the pin 6 of the first operational amplifier U1 and the seventh resistor R7;

[0077] One end of the seventh resistor R7 is connected to the sixth resistor R6 and the pin 6 of the first operational amplifier U1, and the other end of the seventh resistor R7 is connected to the first capacitor C1 and the amplification and filtering module;

[0078] One end of the first capacitor C1 is connected to the seventh resistor R7 and the amplifying and filtering module, and the other end of the first capacitor C1 is grounded.

[0079] Furthermore, the in-phase amplifier 41 includes a second operational amplifier U2, an eighth resistor R8 and a ninth resistor R9; the second low-pass filter 42 includes a tenth resistor R10 and a second capacitor C2. The in-phase amplifier 41 further amplifies the voltage signal Ug outputted by the previous stage to achieve the purpose of increasing the sampling voltage; the second low-pass filter 42 further filters out the AC component of the 6-pin output voltage of the second operational amplifier U2 to prevent spectrum aliasing in subsequent voltage sampling.

[0080] Further, pin 2 of the second operational amplifier U2 is connected to the eighth resistor R8 and the ninth resistor R9; pin 3 of the second operational amplifier U2 is connected to the seventh resistor R7 and the first capacitor C1 in the follower filter module 30; pin 4 of the second operational amplifier U2 is grounded; pin 6 of the second operational amplifier U2 is connected to the ninth resistor R9 and the tenth resistor R10; pin 7 of the second operational amplifier U2 is connected to the second power supply voltage 43; the second power supply voltage is 12V;

[0081] One end of the eighth resistor R8 is connected to the pin 2 of the second operational amplifier U2, and the other end of the eighth resistor R8 is grounded;

[0082] One end of the ninth resistor R9 is connected to the eighth resistor R8 and the second pin 2 of the operational amplifier U2, and the other end of the ninth resistor R9 is connected to the second pin 6 of the operational amplifier U2 and the tenth resistor R10;

[0083] One end of the tenth resistor R10 is connected to the pin 6 of the second operational amplifier U2 and the ninth resistor R9, and the other end of the tenth resistor R10 is connected to the second capacitor C2 and the single chip computer 50;

[0084] One end of the second capacitor C2 is connected to the tenth resistor R10 and the single chip microcomputer 50 , and the other end of the second capacitor C2 is grounded.

[0085] Further, the single-chip microcomputer 50 is an STM32 single-chip microcomputer 50, and the specific model is STM32F103C8T6. The second low-pass filter 42 in the amplification and filtering module is connected to the 10th pin of the single-chip microcomputer 50; the 24th, 36th, 48th and 9th pins of the single-chip microcomputer 50 are connected to a 3.3V voltage, and the 23rd, 35th, 47th and 8th pins of the single-chip microcomputer 50 are grounded. The voltage signal Ug output by the second low-pass filter 42 is connected to the single-chip microcomputer 50 for sampling. The DC voltage value corresponding to the input three-phase AC voltage (i.e., the first voltage UA, the second voltage UB and the third voltage UC) can be obtained through internal sampling and calculation of the single-chip microcomputer 50, and the AC voltage value corresponding to the input three-phase AC voltage can be obtained by proportional conversion.

[0086] The utility model provides an excitation voltage detection device for an exciter. The excitation voltage detection device comprises an excitation voltage detection circuit for an exciter as described in any one of the above.

[0087] The working principle of the excitation voltage detection circuit and detection device of an exciter described in the utility model is:

[0088] An excitation voltage detection circuit for an exciter comprises: an input module, a rectifier module, a follower filter module, an amplifying filter module and a single-chip microcomputer; the input module comprises a transformer and an input three-phase AC voltage, the input three-phase AC voltage is connected to the transformer, and the transformer converts the input three-phase AC voltage into a low-voltage current signal; the rectifier module comprises a rectifier circuit and a first resistor, the rectifier module is connected to the input module, and the low-voltage current signal is rectified by the rectifier circuit and then converted into a voltage signal by the first resistor; the follower filter module is connected to the rectifier module, and the follower filter module comprises a voltage follower and a first low-pass filter; the amplifying filter module is connected to the follower filter module, and the amplifying filter module comprises a common-phase amplifier and a second low-pass filter; the single-chip microcomputer is connected to the amplifying filter module; the voltage signal flows through the follower filter module and the amplifying filter module, and the input three-phase AC voltage value can be obtained through sampling, calculation and conversion inside the single-chip microcomputer.

[0089] For other structures of the excitation voltage detection circuit and detection device of the exciter described in this embodiment, refer to the prior art.

[0090] 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. An excitation voltage detection circuit for an exciter, characterized in that: The detection circuit comprises: An input module (10), the input module (10) comprising a transformer and an input three-phase AC voltage, the input three-phase AC voltage being connected to the transformer, and the transformer converting the input three-phase AC voltage into a low-voltage current signal; A rectifier module (20), the rectifier module (20) comprising a rectifier circuit (21) and a first resistor, the rectifier module (20) being connected to the input module (10), the low-voltage current signal being rectified by the rectifier circuit (21) and then converted into a voltage signal by the first resistor; A follower filter module (30), the follower filter module (30) is connected to the rectifier module (20), and the follower filter module (30) comprises a voltage follower (31) and a first low-pass filter (32); an amplifying and filtering module (40), the amplifying and filtering module (40) being connected to the following filtering module (30), the amplifying and filtering module (40) comprising a common-phase amplifier (41) and a second low-pass filter (42); A single chip microcomputer (50) is connected to the amplifying and filtering module (40); the voltage signal flows through the following filtering module (30) and the amplifying and filtering module (40), and the input three-phase AC voltage value can be obtained through internal sampling, calculation and conversion of the single chip microcomputer (50).

2. The excitation voltage detection circuit of an exciter according to claim 1, characterized in that: The input three-phase AC voltage includes a first voltage, a second voltage and a third voltage; The transformer includes a first transformer, a second transformer and a third transformer; Pin 1 of the first transformer is connected to the first voltage, and pin 2 of the first transformer is connected to the second voltage; Pin 1 of the second transformer is connected to the second voltage, and pin 2 of the second transformer is connected to the third voltage; Pin 1 of the third transformer is connected to the third voltage, and pin 2 of the third transformer is connected to the first voltage.

3. The excitation voltage detection circuit of an exciter according to claim 2, characterized in that: The input module (10) further comprises a second resistor, a third resistor and a fourth resistor; One end of the second resistor is connected to the first voltage, and the other end of the second resistor is connected to pin 1 of the first transformer; One end of the third resistor is connected to the second voltage, and the other end of the third resistor is connected to pin 1 of the second transformer; One end of the fourth resistor is connected to the third voltage, and the other end of the fourth resistor is connected to pin 1 of the third transformer.

4. The excitation voltage detection circuit of an exciter according to claim 2, characterized in that: The rectifier circuit (21) comprises a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth diode, a seventh diode and an eighth diode; The anode of the first diode is connected to the cathode of the fifth diode; The anode of the second diode is connected to the cathode of the sixth diode; The anode of the third diode is connected to the cathode of the seventh diode; The anode of the fourth diode is connected to the cathode of the eighth diode; The cathodes of the first diode, the second diode, the third diode and the fourth diode are all connected together; The anodes of the fifth diode, the sixth diode, the seventh diode and the eighth diode are connected together and grounded; Pin 4 of the first transformer is connected to the anode of the first diode and the cathode of the fifth diode; The 4th pin of the second transformer is connected to the anode of the second diode and the cathode of the sixth diode; Pin 4 of the third transformer is connected to the anode of the third diode and the cathode of the seventh diode; The 3 pins of the first transformer, the second transformer and the third transformer are all connected to the anode of the fourth diode and the cathode of the eighth diode; One end of the first resistor is connected to the anodes of the fifth diode, the sixth diode, the seventh diode and the eighth diode and is grounded, and the other end of the first resistor is connected to the cathodes of the first diode, the second diode, the third diode, the fourth diode and the follower filter module (30).

5. The excitation voltage detection circuit of an exciter according to claim 4, characterized in that: The voltage follower (31) comprises a first operational amplifier U1, a fifth resistor and a sixth resistor; The first low-pass filter (32) includes a seventh resistor and a first capacitor.

6. The excitation voltage detection circuit of an exciter according to claim 5, characterized in that: Pin 3 of the first operational amplifier U1 is connected to the first resistor; Pin 4 of the first operational amplifier U1 is grounded; Pin 2 of the first operational amplifier U1 is connected to one end of the sixth resistor; Pin 6 of the first operational amplifier U1 is connected to the other end of the sixth resistor and the seventh resistor; Pin 7 of the first operational amplifier U1 is connected to a first power supply voltage (33); One end of the fifth resistor is connected to the first resistor in the rectifier module (20), and the other end of the fifth resistor is connected to pin 3 of the first operational amplifier; One end of the sixth resistor is connected to the pin 2 of the first operational amplifier U1, and the other end of the sixth resistor is connected to the pin 6 of the first operational amplifier U1 and the seventh resistor; One end of the seventh resistor is connected to the sixth resistor and the 6th pin of the first operational amplifier U1, and the other end of the seventh resistor is connected to the first capacitor and the amplification and filtering module (40); One end of the first capacitor is connected to the seventh resistor and the amplifying and filtering module (40), and the other end of the first capacitor is grounded.

7. The excitation voltage detection circuit of an exciter according to claim 6, characterized in that: The in-phase amplifier (41) comprises a second operational amplifier U2, an eighth resistor and a ninth resistor; The second low-pass filter (42) includes a tenth resistor and a second capacitor.

8. The excitation voltage detection circuit of an exciter according to claim 7, characterized in that: Pin 2 of the second operational amplifier U2 is connected to the eighth resistor and the ninth resistor; Pin 3 of the second operational amplifier U2 is connected to the seventh resistor and the first capacitor in the follower filter module; Pin 4 of the second operational amplifier U2 is grounded; Pin 6 of the second operational amplifier U2 is connected to the ninth resistor and the tenth resistor; Pin 7 of the second operational amplifier U2 is connected to a second power supply voltage (43); One end of the eighth resistor is connected to the pin 2 of the second operational amplifier U2, and the other end of the eighth resistor is grounded; One end of the ninth resistor is connected to the eighth resistor and the second pin 2 of the operational amplifier U2, and the other end of the ninth resistor is connected to the second pin 6 of the operational amplifier U2 and the tenth resistor; One end of the tenth resistor is connected to the pin 6 of the second operational amplifier U2 and the ninth resistor, and the other end of the tenth resistor is connected to the second capacitor and the single chip computer (50); One end of the second capacitor is connected to the tenth resistor and the single chip computer (50), and the other end of the second capacitor is grounded.

9. The excitation voltage detection circuit of an exciter according to claim 8, characterized in that: The single chip microcomputer (50) is an STM32 single chip microcomputer (50), and the second low pass filter (42) in the amplifying and filtering module (40) is connected to the 10 pin of the single chip microcomputer (50).

10. An excitation voltage detection device for an exciter, characterized in that: An excitation voltage detection circuit for an exciter comprising the method described in any one of claims 1 to 9.