A main control valve refusal and reverse action diagnostic method and system

Abstract

The present application relates to the technical field of water turbine, in particular to a main pressure distributing valve refusing to act and reverse action diagnosis method and system, the steps of the method comprising: obtaining the control signal of proportional servo valve and the displacement feedback signal of main pressure distributing valve; determining the first threshold value corresponding to the opening direction control signal of proportional servo valve, and the second threshold value corresponding to the closing direction control signal of proportional servo valve, determining the third threshold value corresponding to the displacement feedback opening direction signal of main pressure distributing valve, and the fourth threshold value corresponding to the displacement feedback closing direction signal of main pressure distributing valve; comparing the determined each threshold value with the signal corresponding thereto, judging the comparison result under the first setting condition, the second setting condition, the third setting condition and the fourth setting condition respectively, executing the corresponding action of main pressure distributing valve and alarming according to the judgment result, or not executing the alarm according to the judgment result, completing the diagnosis of main pressure distributing valve refusing to act and reverse action.

Description

Technical Field

[0001] This invention relates to the field of water turbine technology, and more specifically, to a method and system for diagnosing main pressure regulating valve failure and reverse operation. Background Technology

[0002] Currently, fault diagnosis of the main pressure distribution valve in a turbine governor system primarily relies on external microswitches. However, this method has several drawbacks: it can only detect malfunctions in the closing direction of the main pressure distribution valve when the unit is under overspeed conditions. Under normal operating conditions, it cannot identify or diagnose malfunctions or reverse actions of the main pressure distribution valve, nor can it reveal the fault type or characteristics. Therefore, a method capable of diagnosing malfunctions and reverse actions of the main pressure distribution valve is urgently needed. Summary of the Invention

[0003] The purpose of this invention is to provide a method and system for diagnosing main pressure regulating valve failure and reverse operation, which eliminates the need for external microswitches and enables online, real-time, rapid, and accurate identification of two faults: failure to operate and reverse operation of the main pressure regulating valve of a turbine governor.

[0004] The embodiments of the present invention are achieved through the following technical solutions:

[0005] A method for diagnosing main pressure regulating valve failure and reverse operation, the method comprising the following steps:

[0006] Acquire the control signal of the proportional servo valve and the displacement feedback signal of the main pressure regulating valve;

[0007] Determine the first threshold corresponding to the opening direction control signal of the proportional servo valve, and the second threshold corresponding to the closing direction control signal of the proportional servo valve; determine the third threshold corresponding to the displacement feedback opening direction signal of the main pressure regulating valve, and the fourth threshold corresponding to the displacement feedback closing direction signal of the main pressure regulating valve.

[0008] Based on the comparison of each determined threshold with its corresponding signal, the comparison results are judged according to the preset first setting condition, second setting condition, third setting condition and fourth setting condition respectively. According to the judgment result, the corresponding action of the main pressure regulating valve is executed and an alarm is triggered, or the alarm is not triggered according to the judgment result, thus completing the diagnosis of the main pressure regulating valve's failure to operate and reverse action.

[0009] Optionally, the displacement feedback signal of the main pressure regulating valve is specifically acquired through the speed controller system, which consists of a processor, a proportional servo valve, and an amplifier circuit board.

[0010] Optionally, the process for acquiring the displacement feedback signal of the main pressure regulating valve is as follows:

[0011] The initial input signal is acquired and amplified by the amplifier circuit board to obtain the output signal of the amplifier circuit board. The output signal of the amplifier circuit board is then input into the proportional servo valve, which performs current / voltage conversion on the output signal of the amplifier circuit board to obtain the feedback signal of the proportional servo valve.

[0012] The feedback signal from the proportional servo valve is output to the processor for recovery processing via current / voltage inverse conversion to obtain the displacement feedback signal of the main pressure regulating valve. The displacement feedback signal of the main pressure regulating valve includes the displacement feedback opening direction signal and the displacement feedback closing direction signal of the main pressure regulating valve.

[0013] Optionally, the specific judgment process for the first set condition is as follows:

[0014] If the opening direction control signal of the proportional servo valve is greater than the first threshold, then the displacement feedback opening direction signal of the main pressure regulating valve is less than the third threshold. If the displacement feedback opening direction signal of the main pressure regulating valve is less than the third threshold, then the display duration of both the opening direction control signal of the proportional servo valve and the displacement feedback opening direction signal of the main pressure regulating valve is greater than the first preset duration. If the above judgment results are all yes, then the main pressure regulating valve is determined to refuse to perform the action in the opening direction and an alarm is triggered; otherwise, no alarm is triggered.

[0015] Optionally, the specific judgment process for the second set condition is as follows:

[0016] If the closing direction control signal of the proportional servo valve is greater than the second threshold, then the displacement feedback closing direction signal of the main pressure regulating valve is less than the fourth threshold. If the displacement feedback closing direction signal of the main pressure regulating valve is less than the fourth threshold, then the display duration of both the closing direction control signal of the proportional servo valve and the displacement feedback closing direction signal of the main pressure regulating valve is greater than the second preset duration. If the above judgment results are all yes, then the main pressure regulating valve is determined to refuse to perform the action in the closing direction and an alarm is triggered; otherwise, no alarm is triggered.

[0017] Optionally, the specific judgment process for the third set condition is as follows:

[0018] If the closing direction control signal of the proportional servo valve is greater than the second threshold, then the displacement feedback opening direction signal of the main pressure regulating valve is greater than the third threshold. If the display duration of both the closing direction control signal of the proportional servo valve and the displacement feedback opening direction signal of the main pressure regulating valve is greater than the third preset duration, then if the above judgment results are all yes, then the main pressure regulating valve is determined to perform a reverse action and an alarm is triggered; otherwise, no alarm is triggered.

[0019] Optionally, the specific judgment process for the fourth set condition is as follows:

[0020] If the opening direction control signal of the proportional servo valve is greater than the first threshold, then the displacement feedback closing direction signal of the main pressure regulating valve is greater than the fourth threshold. If the displacement feedback closing direction signal of the main pressure regulating valve is greater than the fourth threshold, then the display duration of both the opening direction control signal of the proportional servo valve and the displacement feedback closing direction signal of the main pressure regulating valve is greater than the fourth preset duration. If the above judgment results are all yes, then the main pressure regulating valve is determined to perform a reverse action and an alarm is triggered; otherwise, no alarm is triggered.

[0021] Optionally, in the specific judgment process of the first, second, third and fourth set conditions, the judgment order can be a sequential judgment order, an arbitrary judgment order or a simultaneous judgment order.

[0022] A diagnostic system for main pressure regulating valve failure and reverse action includes: a determining unit, configured to determine a first threshold corresponding to the opening direction control signal of a proportional servo valve, a second threshold corresponding to the closing direction control signal of a proportional servo valve, a third threshold corresponding to the displacement feedback opening direction signal of a main pressure regulating valve, and a fourth threshold corresponding to the displacement feedback closing direction signal of a main pressure regulating valve; an acquiring unit, configured to acquire the opening direction control signal of the proportional servo valve, the closing direction control signal of the proportional servo valve, the displacement feedback opening direction signal of the main pressure regulating valve, and the displacement feedback closing direction signal of the main pressure regulating valve; and a diagnostic unit, configured to compare each determined threshold with its corresponding signal, and diagnose the comparison results according to preset first, second, third, and fourth setting conditions.

[0023] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0024] This embodiment compares the output values ​​of the proportional servo valve opening direction control signal, the proportional servo valve closing direction control signal, the main pressure regulating valve displacement feedback opening direction signal, and the main pressure regulating valve displacement feedback closing direction signal with a preset threshold. This allows for the identification of two faults in the turbine governor's main pressure regulating valve: failure to operate and reverse operation. It does not require microswitches or unit speed conditions and can identify the turbine governor's main pressure regulating valve failure to operate and reverse operation online in real time, quickly, and accurately. Attached Figure Description

[0025] Figure 1 A flowchart illustrating a diagnostic method for main pressure regulating valve failure and reverse operation provided by the present invention;

[0026] Figure 2 A schematic diagram showing the distribution of fault causes of the main pressure regulating valve provided by the present invention;

[0027] Figure 3 A flowchart illustrating the first judgment condition provided by the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0029] like Figure 2 As shown, the present invention provides a fault diagnosis for the main pressure regulating valve, which mainly includes three aspects: (1) the main pressure regulating valve of the speed controller fails to move in the opening direction: that is, the main pressure regulating valve of the speed controller is to be moved in the opening direction, but the main pressure regulating valve malfunctions and does not move in the opening direction; (2) the main pressure regulating valve of the speed controller fails to move in the closing direction: that is, the main pressure regulating valve of the speed controller is to be moved in the closing direction, but the main pressure regulating valve malfunctions and does not move in the closing direction; (3) the main pressure regulating valve of the speed controller moves in the reverse direction: that is, the main pressure regulating valve is to be moved in the opening direction, but the main pressure regulating valve malfunctions and moves in the closing direction (opposite direction); or, the main pressure regulating valve is to be moved in the closing direction, but the main pressure regulating valve malfunctions and moves in the opening direction (opposite direction).

[0030] Based on this, such as Figure 1 As shown, the present invention provides one embodiment: a method for diagnosing the failure and reverse action of a main pressure regulating valve, the method comprising the following steps:

[0031] A first threshold corresponding to the opening direction control signal of the proportional servo valve, a second threshold corresponding to the closing direction control signal of the proportional servo valve, a third threshold corresponding to the opening direction signal of the main pressure regulating valve displacement feedback, and a fourth threshold corresponding to the closing direction signal of the main pressure regulating valve displacement feedback are predetermined.

[0032] The threshold values ​​can be determined based on historical experience and set manually. In some embodiments, the first and second thresholds can be the same, such as setting both the first and second thresholds to 15%; the third and fourth thresholds can be the same, but the value of the third threshold differs from that of the first threshold, such as setting both the third and fourth thresholds to 10%.

[0033] In practical applications, a hydropower station has eight 600MW turbine generator units. The movement of the governor's main pressure distribution valve affects the increase or decrease of the guide vane opening. Timely acquisition of the main pressure distribution valve displacement feedback signal can improve the governor's control accuracy. When the main pressure distribution valve becomes stuck, the governor control system can respond promptly and identify the fault. However, current monitoring of the governor's main pressure distribution valve displacement feedback signal is generally achieved by connecting an external main pressure distribution signal monitoring device to the governor control system. This external main pressure distribution valve displacement feedback signal monitoring device needs to determine the main pressure distribution valve displacement feedback signal through its own mechanical movement. This structure cannot accurately reflect the signal status of the A / B sets of main pressure distribution displacement sensors actually involved in the regulation calculation. Thus, if the hydropower station unit experiences a main pressure distribution valve slippage fault, it cannot provide an accurate method for monitoring the main pressure distribution valve displacement feedback signal, resulting in an inability to quickly and accurately identify the fault point, requiring personnel to invest a significant amount of time in troubleshooting.

[0034] Based on this, we need to obtain the proportional servo valve opening direction control signal, the proportional servo valve closing direction control signal, the main pressure regulating valve displacement feedback opening direction signal, and the main pressure regulating valve displacement feedback closing direction signal.

[0035] In this embodiment, the output values ​​of the proportional servo valve opening direction control signal and the proportional servo valve closing direction control signal in the turbine governor system can be acquired in real time.

[0036] The main pressure regulating valve displacement feedback opening direction signal and the main pressure regulating valve displacement feedback closing direction signal need to be obtained through the following methods:

[0037] The main pressure regulating valve displacement feedback signal (i.e., the initial input signal described in this invention, which is unknown to the processor in the speed controller system) is input to the amplifier circuit board of the speed controller system. The amplifier circuit board amplifies the main pressure regulating valve displacement feedback signal to obtain the output signal of the amplifier board. Subsequently, the amplifier circuit board inputs this output signal into the proportional servo valve, which converts the output signal to obtain the proportional servo valve feedback signal. Then, the proportional servo valve outputs the feedback signal to the processor in the speed controller system. At this point, to monitor the main pressure regulating valve displacement feedback signal, the speed controller system can use the processor to restore the proportional servo valve feedback signal, thereby obtaining the main pressure regulating valve displacement feedback signal.

[0038] The proportional servo valve and amplification circuit board in the speed controller control system perform current / voltage conversion processing on the main pressure valve displacement feedback signal unknown to the processor to obtain the proportional servo valve feedback signal, which is then output to the processor in the speed controller control system. This allows the processor in the speed controller control system to directly recover the main pressure valve displacement feedback signal by current / voltage inverse conversion, thereby effectively avoiding the generation of monitoring errors and obtaining the main pressure valve displacement feedback signal faster.

[0039] In this embodiment, the speed controller control system includes at least a processor, a proportional servo valve, and an amplifier board. The proportional servo valve has an integrated electronic circuit (OBE) structure with a second-stage operational amplifier. The main pressure regulating valve is a GE FC series main pressure regulating valve.

[0040] By directly restoring the acquired proportional servo valve feedback signal through the speed governor control system itself, the main pressure regulating valve displacement feedback signal can be obtained in real time, thereby enabling the monitoring of the main pressure regulating valve displacement feedback signal. This monitoring method eliminates the need for external equipment, reducing the size of the device and providing the main pressure regulating valve displacement feedback signal to the speed governor control system accurately and quickly.

[0041] In addition, in the specific application of this embodiment, the proportional servo valve feedback signal is solved using the formula: D = (C - 12) * R to obtain the input signal of the proportional servo valve feedback; where D is the input signal of the proportional servo valve feedback, C is the proportional servo valve feedback signal, and R is the fixed resistance value in the proportional servo valve. The median signal value is 12. The fixed resistance value R is calculated by the voltage-to-current module in the proportional servo valve. The proportional servo valve feedback signal is a current signal, and the proportional servo valve feedback input signal is a voltage signal. The input signal of the proportional servo valve feedback is solved using the formula: A = D * K to obtain the main pressure regulating valve displacement feedback signal; where A is the main pressure regulating valve displacement feedback signal, D is the input signal of the proportional servo valve feedback, and K is the amplification gain of the amplifier board in the speed controller system.

[0042] In this embodiment, diagnosing whether the main pressure regulating valve refuses to open is determined by the output values ​​of the proportional servo valve's opening direction control signal and the main pressure regulating valve's displacement feedback opening direction signal. Similarly, diagnosing whether the main pressure regulating valve refuses to close is determined by the output values ​​of the proportional servo valve's closing direction control signal and the main pressure regulating valve's displacement feedback closing direction signal. Furthermore, since there are two types of reverse motion faults, the corresponding judgment methods for diagnosing whether the main pressure regulating valve is moving in reverse are also divided into two types. This requires comparing the collected output values ​​of the proportional servo valve's opening direction control signal, proportional servo valve's closing direction control signal, main pressure regulating valve's displacement feedback opening direction signal, and main pressure regulating valve's displacement feedback closing direction signal with pre-set thresholds. This allows for the identification of two faults: the turbine governor's main pressure regulating valve refusing to move and reverse motion. Thus, without the need for microswitches or the unit operating at 115% speed, online, real-time, rapid, and accurate identification of the turbine governor's main pressure regulating valve refusing to move and reverse motion is possible.

[0043] like Figure 3 As shown, this embodiment performs the following judgment process through the first setting condition, the second setting condition, the third setting condition, and the fourth setting condition, respectively, in order to achieve the identification and diagnosis of the main pressure regulating valve's failure to operate and reverse operation.

[0044] First setting condition: Determine whether the output value of the proportional servo valve opening direction control signal is greater than the first threshold. If the output value of the proportional servo valve opening direction control signal is greater than the first threshold, then continue to determine whether the output value of the main pressure regulating valve displacement feedback opening direction signal is less than the third threshold. If the output value of the main pressure regulating valve displacement feedback opening direction signal is less than the third threshold, then continue to determine whether the display duration of both the proportional servo valve opening direction control signal and the main pressure regulating valve displacement feedback opening direction signal is greater than the first duration. If all the above conditions are met, then determine that the main pressure regulating valve refuses to perform the action in the opening direction and issue an alarm; otherwise, do not issue an alarm.

[0045] The second setting condition is as follows: Determine whether the output value of the proportional servo valve closing direction control signal is greater than the second threshold. If the output value of the proportional servo valve closing direction control signal is greater than the second threshold, then continue to determine whether the output value of the main pressure regulating valve displacement feedback closing direction signal is less than the fourth threshold. If the output value of the main pressure regulating valve displacement feedback closing direction signal is less than the fourth threshold, then continue to determine whether the display duration of both the proportional servo valve closing direction control signal and the main pressure regulating valve displacement feedback closing direction signal is greater than the second duration. If all the above conditions are met, then determine that the main pressure regulating valve refuses to perform the action in the closing direction and issue an alarm; otherwise, do not issue an alarm.

[0046] The third setting condition is as follows: Determine whether the output value of the proportional servo valve closing direction control signal is greater than the second threshold. If the output value of the proportional servo valve closing direction control signal is greater than the second threshold, then continue to determine whether the output value of the main pressure regulating valve displacement feedback opening direction signal is greater than the third threshold. If the output value of the main pressure regulating valve displacement feedback opening direction signal is greater than the third threshold, then continue to determine whether the display duration of both the proportional servo valve closing direction control signal and the main pressure regulating valve displacement feedback opening direction signal is greater than the third duration. If all the above conditions are met, then determine that the main pressure regulating valve performs a reverse action and triggers an alarm; otherwise, no alarm is triggered.

[0047] Fourth setting condition: Determine whether the output value of the proportional servo valve opening direction control signal is greater than the first threshold. If the output value of the proportional servo valve opening direction control signal is greater than the first threshold, then continue to determine whether the output value of the main pressure regulating valve displacement feedback closing direction signal is greater than the fourth threshold. If the output value of the main pressure regulating valve displacement feedback closing direction signal is greater than the fourth threshold, then continue to determine whether the display duration of both the proportional servo valve opening direction control signal and the main pressure regulating valve displacement feedback closing direction signal is greater than the fourth duration. If all the above conditions are met, then determine that the main pressure regulating valve performs a reverse action and triggers an alarm; otherwise, do not trigger an alarm.

[0048] In the specific application of this embodiment, the first duration, the second duration, the third duration and the fourth duration (i.e. the first preset duration in this article, etc., which will not be described in detail here) can be set to 1 second.

[0049] It should be noted that the order of execution of the above judgment conditions is only illustrative. In actual execution, the order of execution of the above judgment conditions is not limited and can be any order. Of course, the above judgment conditions can also be executed simultaneously, and there is no restriction on this.

[0050] In addition, regarding the above, the present invention also provides another embodiment: a diagnostic system for main pressure regulating valve failure and reverse action, comprising: a determining unit, configured to pre-determine, in a turbine governor system, a first threshold corresponding to the proportional servo valve opening direction control signal, a second threshold corresponding to the proportional servo valve closing direction control signal, a third threshold corresponding to the main pressure regulating valve displacement feedback opening direction signal, and a fourth threshold corresponding to the main pressure regulating valve displacement feedback closing direction signal; an acquiring unit, configured to acquire the proportional servo valve opening direction control signal, the proportional servo valve closing direction control signal, the main pressure regulating valve displacement feedback opening direction signal, and the main pressure regulating valve displacement feedback closing direction signal; and a diagnostic unit, configured to, based on the proportional servo valve opening direction control signal and the first threshold, pre-determine, a first threshold corresponding to the proportional servo valve closing direction control signal, the second threshold corresponding to the proportional servo valve closing direction control signal, and the third threshold corresponding to ... second threshold corresponding to the proportional servo valve closing direction control signal, the third threshold corresponding to the main pressure regulating valve displacement feedback opening direction signal, and the fourth threshold corresponding to the main pressure regulating valve displacement feedback closing direction signal; and a diagnostic unit, configured to, based on the proportional servo valve opening direction control signal and the first threshold, pre-determine, a second threshold corresponding to the proportional servo valve closing direction control signal, the third threshold corresponding to the main pressure regulating valve displacement feedback closing direction signal; and a diagnostic unit, configured to, based on the proportional servo valve closing direction control signal and the first threshold, pre-determine, a second threshold corresponding to the proportional servo valve closing The system diagnoses the failure to open the main pressure regulating valve based on the threshold, the main pressure regulating valve displacement feedback opening direction signal, and the third threshold; it also diagnoses the failure to close the main pressure regulating valve based on the proportional servo valve closing direction control signal, the second threshold, the main pressure regulating valve displacement feedback closing direction signal, and the fourth threshold; it further diagnoses the reverse action of the main pressure regulating valve based on the proportional servo valve closing direction control signal, the second threshold, the main pressure regulating valve displacement feedback opening direction signal, and the third threshold; and it also diagnoses the reverse action of the main pressure regulating valve based on the proportional servo valve opening direction control signal, the first threshold, the main pressure regulating valve displacement feedback closing direction signal, and the fourth threshold.

[0051] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for diagnosing failure and reverse operation of a main pressure regulating valve, characterized in that, The steps of this method include: Acquire the control signal of the proportional servo valve and the displacement feedback signal of the main pressure regulating valve; Determine the first threshold corresponding to the opening direction control signal of the proportional servo valve, and the second threshold corresponding to the closing direction control signal of the proportional servo valve; determine the third threshold corresponding to the displacement feedback opening direction signal of the main pressure regulating valve, and the fourth threshold corresponding to the displacement feedback closing direction signal of the main pressure regulating valve. Based on the comparison of each determined threshold with its corresponding signal, the comparison results are judged according to the preset first setting condition, second setting condition, third setting condition and fourth setting condition respectively. The corresponding action of the main pressure regulating valve is executed and an alarm is triggered according to the judgment result, or no alarm is triggered according to the judgment result, thus completing the diagnosis of the main pressure regulating valve's failure to operate and reverse action. The displacement feedback signal of the main pressure regulating valve is specifically obtained through the speed controller control system, which consists of a processor, a proportional servo valve, and an amplifier circuit board. The process of acquiring the displacement feedback signal of the main pressure regulating valve is as follows: The initial input signal is acquired and amplified by the amplifier circuit board to obtain the output signal of the amplifier circuit board. The output signal of the amplifier circuit board is then input into the proportional servo valve, which performs current / voltage conversion on the output signal of the amplifier circuit board to obtain the feedback signal of the proportional servo valve. The feedback signal from the proportional servo valve is output to the processor for recovery processing via current / voltage inverse conversion to obtain the displacement feedback signal of the main pressure regulating valve. The displacement feedback signal of the main pressure regulating valve includes the displacement feedback opening direction signal and the displacement feedback closing direction signal of the main pressure regulating valve.

2. The diagnostic method for main pressure regulating valve failure and reverse operation according to claim 1, characterized in that, The specific judgment process for the first set condition is as follows: If the opening direction control signal of the proportional servo valve is greater than the first threshold, then the displacement feedback opening direction signal of the main pressure regulating valve is less than the third threshold. If the displacement feedback opening direction signal of the main pressure regulating valve is less than the third threshold, then the display duration of both the opening direction control signal of the proportional servo valve and the displacement feedback opening direction signal of the main pressure regulating valve is greater than the first preset duration. If the above judgment results are all yes, then the main pressure regulating valve is determined to refuse to perform the action in the opening direction and an alarm is triggered; otherwise, no alarm is triggered.

3. The diagnostic method for main pressure regulating valve failure and reverse operation according to claim 1, characterized in that, The specific judgment process for the second set condition is as follows: If the closing direction control signal of the proportional servo valve is greater than the second threshold, then the displacement feedback closing direction signal of the main pressure regulating valve is less than the fourth threshold. If the displacement feedback closing direction signal of the main pressure regulating valve is less than the fourth threshold, then the display duration of both the closing direction control signal of the proportional servo valve and the displacement feedback closing direction signal of the main pressure regulating valve is greater than the second preset duration. If the above judgment results are all yes, then the main pressure regulating valve is determined to refuse to perform the action in the closing direction and an alarm is triggered; otherwise, no alarm is triggered.

4. The diagnostic method for main pressure regulating valve failure and reverse operation according to claim 1, characterized in that, The specific judgment process for the third set condition is as follows: If the closing direction control signal of the proportional servo valve is greater than the second threshold, then if it is greater than the second threshold, then if the displacement feedback opening direction signal of the main pressure regulating valve is greater than the third threshold, then if it is greater than the third threshold, then if the display duration of the closing direction control signal of the proportional servo valve and the displacement feedback opening direction signal of the main pressure regulating valve are both greater than the third preset duration, then if the above judgment results are all yes, then it is determined that the main pressure regulating valve performs a reverse action and an alarm is triggered. Otherwise, the alarm will not be triggered.

5. The diagnostic method for main pressure regulating valve failure and reverse operation according to claim 1, characterized in that, The specific judgment process for the fourth preset condition is as follows: If the opening direction control signal of the proportional servo valve is greater than the first threshold, then the displacement feedback closing direction signal of the main pressure regulating valve is greater than the fourth threshold. If the displacement feedback closing direction signal of the main pressure regulating valve is greater than the fourth threshold, then the display duration of both the opening direction control signal of the proportional servo valve and the displacement feedback closing direction signal of the main pressure regulating valve is greater than the fourth preset duration. If the above judgment results are all yes, then the main pressure regulating valve is determined to perform a reverse action and an alarm is triggered; otherwise, no alarm is triggered.

6. The method for diagnosing the failure and reverse action of the main pressure regulating valve according to any one of claims 1-5, characterized in that, In the specific judgment process of the first setting condition, the second setting condition, the third setting condition and the fourth setting condition, the judgment order is either a sequential judgment order, an arbitrary judgment order or a simultaneous judgment order.

7. A diagnostic system for main pressure regulating valve failure and reverse action, characterized in that, include: The system includes a determining unit for determining a first threshold corresponding to the opening direction control signal of the proportional servo valve, a second threshold corresponding to the closing direction control signal of the proportional servo valve, a third threshold corresponding to the displacement feedback opening direction signal of the main pressure regulating valve, and a fourth threshold corresponding to the displacement feedback closing direction signal of the main pressure regulating valve; an acquiring unit for acquiring the opening direction control signal of the proportional servo valve, the closing direction control signal of the proportional servo valve, the displacement feedback opening direction signal of the main pressure regulating valve, and the displacement feedback closing direction signal of the main pressure regulating valve; and a diagnostic unit for comparing each determined threshold with its corresponding signal, and diagnosing the comparison results based on preset first, second, third, and fourth setting conditions. The displacement feedback signal of the main pressure regulating valve is specifically obtained through the speed controller control system, which consists of a processor, a proportional servo valve, and an amplifier circuit board. The process of acquiring the displacement feedback signal of the main pressure regulating valve is as follows: The initial input signal is acquired and amplified by the amplifier circuit board to obtain the output signal of the amplifier circuit board. The output signal of the amplifier circuit board is then input into the proportional servo valve, which performs current / voltage conversion on the output signal of the amplifier circuit board to obtain the feedback signal of the proportional servo valve. The feedback signal from the proportional servo valve is output to the processor for recovery processing via current / voltage inverse conversion to obtain the displacement feedback signal of the main pressure regulating valve. The displacement feedback signal of the main pressure regulating valve includes the displacement feedback opening direction signal and the displacement feedback closing direction signal of the main pressure regulating valve.

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