Self-generating rotary valve mud pulse generator, simulation decoding device and method

Abstract

The invention relates to the technical field of petroleum and natural gas drilling engineering, in particular to a self-power-generation type rotary valve mud pulse generator, a simulation decoding device and a simulation decoding method. The generator comprises a turbine generator, a control circuit, a brushless direct current motor, a magnetic transmission assembly and a rotary valve mechanism; the turbine generator generates electricity through drilling fluid and supplies power to the control circuit to drive the motor to rotate. The magnetic transmission assembly comprises a magnetic meshing device, a speed reducer and a self-resetting device; the magnetic meshing device realizes non-contact torque transmission through inner and outer magnetic rotors and an isolation sleeve, and isolates a motor cavity from a slurry environment; the self-resetting device drives the rotary valve rotor to automatically reset during power failure through cooperation of permanent magnets on the inner and outer rotating shafts. According to the invention, the functions of self-power-generation driving, reliable dynamic sealing and power-off safe resetting are realized.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling engineering technology, and in particular to a self-generating rotary valve mud pulse generator, a simulation decoding device, and a method. Background Technology

[0002] Measurement while drilling (MWD) technology is a key technology for real-time monitoring and transmission of downhole parameters in modern oil and gas drilling engineering. As the core execution component of the MWD system, the mud pulse generator generates pressure pulse signals by changing the flow area of ​​the drilling fluid, and transmits downhole data to the surface.

[0003] Existing rotary valve mud pulse generators typically use a motor to drive the rotary valve, and their power supply mainly relies on battery packs or surface power cables. However, battery packs not only have a limited lifespan and are greatly affected by ambient temperature, but also pose environmental pressures and compliance risks in the disposal of waste batteries; while cable power supply increases the complexity of the drill string structure, limiting its adaptability to complex well conditions.

[0004] Furthermore, traditional rotary valve drive mechanisms typically employ mechanical seals or packing seals to isolate the motor cavity from the drilling fluid environment when connecting the motor and the rotary valve. Due to the high sand content, high abrasiveness, and high pressure characteristics of drilling fluid, dynamic sealing components are highly susceptible to wear or failure under harsh operating conditions. This can lead to drilling fluid intrusion into the motor cavity, causing short circuits and burnout, severely reducing the tool's mean time between failures (MTBF).

[0005] More importantly, during drilling operations, if a power outage or control failure causes the rotary valve rotor to remain in the throttling position, it will block the drilling fluid flow path, leading to a "pump stall" accident and seriously threatening downhole safety. Existing mechanical reset mechanisms mostly use torsion springs or compression springs, which are prone to fatigue fracture under long-term operation in the high-temperature and high-pressure environment downhole. Furthermore, the spring mechanism is easily jammed by sand particles in the drilling fluid, causing the reset function to fail.

[0006] In summary, existing mud pulse generators still face technical bottlenecks that urgently need to be addressed in terms of power supply reliability, dynamic seal life, and power failure safety reset mechanism. Summary of the Invention

[0007] Therefore, the present invention provides a self-generating rotary valve mud pulse generator, an analog decoding device and method to solve the aforementioned problems existing in the prior art.

[0008] To achieve the above objectives, the present invention provides a self-generating rotary valve mud pulse generator, comprising: a turbine generator, a control circuit, a brushless DC motor, a magnetic drive assembly, and a rotary valve mechanism;

[0009] The turbine generator is installed in the drilling fluid flow channel, and its power output terminal is electrically connected to the control circuit to convert the kinetic energy of the drilling fluid into electrical energy and supply power to the control circuit.

[0010] The control signal output terminal of the control circuit is electrically connected to the brushless DC motor and is used to drive the brushless DC motor to rotate.

[0011] The output shaft of the brushless DC motor is connected to the input end of the magnetic drive assembly;

[0012] The magnetic drive assembly includes a magnetic engagement device, a reducer, and a self-resetting device connected sequentially along the power transmission path.

[0013] The magnetic meshing device includes an inner magnetic rotor and an outer magnetic rotor, which are separated by a non-magnetic isolation sleeve. The inner magnetic rotor is connected to the output shaft of the brushless DC motor, and the outer magnetic rotor is connected to the input shaft of the reducer. This is used to achieve non-contact torque transmission and isolate the motor cavity from the sand-containing mud environment.

[0014] The output shaft of the reducer is connected to the inner rotating shaft of the self-resetting device;

[0015] The self-resetting device includes an inner rotating shaft and an outer rotating shaft arranged coaxially, with the outer rotating shaft fixed to the housing; two pairs of permanent magnets with alternating N and S poles are fixed to the outer circumference of the inner rotating shaft and the inner circumference of the outer rotating shaft, respectively.

[0016] The rotary valve mechanism includes a rotary valve stator and a rotary valve rotor. The rotary valve stator is fixedly installed, and the rotary valve rotor is connected to the inner rotating shaft of the self-resetting device.

[0017] Furthermore, the maximum designed operating angle of the rotary valve rotor is 45°; the number of pole pairs p of the permanent magnet in the self-resetting device is related to the maximum operating angle. Satisfying Relationship: ≤ 90°;

[0018] When power is interrupted due to pump stoppage or displacement fluctuation, the restoring torque generated by the self-resetting device increases monotonically with the deflection angle in the range of 0° to 45°, and the system has only one stable equilibrium position throughout the entire operating range.

[0019] Furthermore, the product of the number of magnetic pole pairs of the self-resetting device and the maximum working angle is set to 90 degrees; at this maximum working angle position, the relative electrical angle between the inner and outer rotating shafts reaches 90 degrees, and the restoring torque generated by the permanent magnet self-resetting component increases monotonically with the increase of the angle within the stroke from 0 degrees to the maximum working angle.

[0020] Furthermore, the self-resetting device adopts an axial nested structure, with the inner rotating shaft coaxially fitted inside the outer rotating shaft; the output shaft of the reducer is rigidly connected to the inner rotating shaft, the inner rotating shaft serves as the main transmission shaft, and its outer circumferential surface serves as the mounting carrier for the permanent magnet.

[0021] Furthermore, the control circuit includes a microcontroller and an H-bridge drive circuit, and is configured with predictive protection logic;

[0022] The microcontroller monitors the output voltage of the turbine generator in real time. When the voltage is detected to be lower than the preset threshold and continues for a set time, it determines that the power supply is abnormal and triggers the safety reset process first, driving the rotary valve rotor to return to the fully open position, thereby realizing active safety control before power failure.

[0023] On the other hand, the present invention provides an analog decoding device for a self-generating rotary valve mud pulse generator, comprising:

[0024] The test box is used to provide operating power to the pulse generator and output control command signals that are analog downhole encoded.

[0025] An infrared diffuse reflection photoelectric switch is installed on the outside of the rotary valve stator of the pulse generator. Its beam is directly facing the movement trajectory area of ​​the rotor blades. The photoelectric switch integrates a transmitter and a receiver. When a reflective surface exists within the detection distance, the receiver captures the reflected light and outputs a high level; otherwise, it outputs a low level.

[0026] An interface box is electrically connected to the infrared diffuse reflection photoelectric switch and is used to collect its output signal and perform level conversion and transmission.

[0027] The host computer is communicatively connected to the interface box and is used to receive signals, decode status, and record and store them.

[0028] Specifically, when the rotary valve rotor rotates to the throttling position, the rotor blades enter the detection area of ​​the photoelectric switch, forming a reflective surface and outputting a high level; when the rotor is in the 0° fully open position, there are no blades blocking the light, no effective reflection, and outputting a low level.

[0029] The high / low level sequence constitutes a simulated mud pressure pulse signal, which is used to verify the function of the pulse generator under normal pressure.

[0030] Furthermore, the infrared diffuse reflection photoelectric switch is a PNP type normally open output mode photoelectric switch, whose sensing distance and sensitivity are adjustable, and its installation position corresponds to the throttling critical angle region of the rotary valve mechanism.

[0031] In another aspect, the present invention also provides an analog decoding method for an analog decoding device, comprising:

[0032] Step S1: Power is supplied to the pulse generator through the test box, and control command signals simulating downhole coding are output.

[0033] Step S2: Drive the rotary valve rotor to reciprocate between the fully open position and the maximum throttling position;

[0034] Step S3: The position of the rotor blades is detected in real time using an infrared diffuse reflection photoelectric switch. When the rotor blades enter the detection area and form a reflective surface, a high-level signal is output, and when the rotor blades leave the detection area, a low-level signal is output.

[0035] In step S4, the host computer reconstructs the received level sequence into a simulated mud pressure pulse waveform based on the mapping relationship that high level corresponds to throttling state and low level corresponds to fully open state, and calculates the pulse width and on / off response time.

[0036] Furthermore, step S4 also includes comparing the reconstructed analog waveform with the theoretical encoded waveform. If the level transition delay or duration deviation is detected to exceed a preset threshold, it is determined that the rotary valve is mechanically stuck or the control logic is abnormal.

[0037] Furthermore, the analog decoding method further includes:

[0038] The test box outputs a simulated power supply voltage that decreases at a preset slope. The control circuit of the pulse generator is monitored to see if it triggers a safety reset process when the voltage drops to a threshold. Combined with the waveform response time recorded by the host computer, the reset reliability of the self-reset device under simulated power interruption conditions is verified.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention converts the kinetic energy of drilling fluid into electrical energy to drive the system through a turbine generator, achieving energy self-sufficiency; the magnetic meshing device utilizes the characteristic of magnetic field penetrating non-magnetic isolation sleeve to achieve non-contact torque transmission, which physically isolates sand-containing mud from the motor cavity while ensuring transmission efficiency, completely eliminating the risk of medium intrusion caused by dynamic seal wear; the self-resetting device, based on the magnetic torque angle characteristics between the permanent magnets of the inner and outer rotating shafts, uses the restoring torque automatically generated by magnetic potential energy to drive the rotary valve rotor to reset to the fully open position when the active driving torque is lost due to power failure, effectively preventing downhole pressure accidents caused by rotary valve closure, and significantly improving the sealing life and intrinsic safety of the system. Attached Figure Description

[0040] Figure 1 A schematic diagram of the structure of a self-generating rotary valve mud pulse generator provided by the present invention;

[0041] Figure 2 A schematic diagram of the internal structure of a turbine generator for a self-generating rotary valve mud pulse generator provided by the present invention;

[0042] Figure 3 The present invention provides the arrangement and relative position relationship of permanent magnets on the inner and outer rotating shafts of a self-resetting device for a self-generating rotary valve mud pulse generator.

[0043] Figure 4 A comparison diagram of the window overlap state of the rotary valve mechanism of a self-generating rotary valve mud pulse generator provided by the present invention at the 0° fully open position and the 45° throttling position, and a schematic diagram of the corresponding simulated mud pressure pulse waveform.

[0044] Figure 5 This is a schematic diagram of the structural connection of the analog decoding device provided by the present invention;

[0045] Reference numerals in the attached diagram: 1. Turbine generator; 2. Control circuit; 3. Brushless DC motor; 4. Magnetic meshing device; 5. Reducer; 6. Self-resetting device; 7. Rotary valve rotor; 8. Rotary valve stator; 9. Test box; 10. Infrared diffuse reflection photoelectric switch; 11. Interface box; 12. Host computer. Detailed Implementation

[0046] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0047] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0048] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0049] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0050] Specifically, the present invention is applicable to ultra-deep well operation environments with bottom hole temperature ≥175℃, drilling fluid sand content ≥3%, and well inclination angle ≥85°.

[0051] Please see Figure 1 As shown, the present invention provides a self-generating rotary valve mud pulse generator, comprising: a turbine generator 1, a control circuit 2, a brushless DC motor 3, a magnetic drive assembly, and a rotary valve mechanism;

[0052] The turbine generator 1 is installed in the drilling fluid flow channel, and its power output terminal is electrically connected to the control circuit 2 to convert the kinetic energy of the drilling fluid into electrical energy and supply power to the control circuit 2.

[0053] The control signal output terminal of the control circuit 2 is electrically connected to the brushless DC motor 3 and is used to drive the brushless DC motor 3 to rotate.

[0054] The output shaft of the brushless DC motor 3 is connected to the input end of the magnetic drive assembly;

[0055] The magnetic drive assembly includes a magnetic meshing device 4, a reducer 5, and a self-resetting device 6 connected sequentially along the power transmission path.

[0056] The magnetic meshing device 4 includes an inner magnetic rotor and an outer magnetic rotor, which are separated by a non-magnetic isolation sleeve. The inner magnetic rotor is connected to the output shaft of the brushless DC motor 3, and the outer magnetic rotor is connected to the input shaft of the reducer 5. This is used to achieve non-contact torque transmission and isolate the motor cavity from the sand-containing mud environment.

[0057] The output shaft of the reducer 5 is connected to the inner rotating shaft of the self-resetting device 6;

[0058] The self-resetting device 6 includes an inner rotating shaft and an outer rotating shaft arranged coaxially, with the outer rotating shaft fixed to the housing; two pairs of permanent magnets with alternating N and S poles are fixed to the outer circumference of the inner rotating shaft and the inner circumference of the outer rotating shaft, respectively.

[0059] The rotary valve mechanism includes a rotary valve stator 8 and a rotary valve rotor 7. The rotary valve stator 8 is fixedly installed, and the rotary valve rotor 7 is connected to the inner rotating shaft of the self-resetting device 6.

[0060] Specifically, this embodiment provides a self-generating rotary valve mud pulse generator, which has an overall cylindrical structure and is installed in series in the drill collar at the bottom of the drill string. It mainly consists of a turbine generator 1, a control circuit 2, a brushless DC motor 3, a magnetic engagement device 4, a reducer 5, a self-resetting device 6, and a rotary valve mechanism (including a rotary valve rotor 7 and a rotary valve stator 8) arranged sequentially along the axial direction. The functional chambers are isolated by perfluoroether rubber sealing rings (temperature resistant to 230°C) to ensure that electronic components are protected from intrusion by high-sand-content mud.

[0061] 1. Turbine generator

[0062] The turbine generator 1 is installed in the main drilling fluid channel. For example... Figure 2 As shown, its rotor section adopts a multi-stage stainless steel turbine blade structure (preferably 5 stages). The blades are streamlined and rectified by guide wheels to maximize the capture of drilling fluid kinetic energy. When the drilling fluid discharge reaches the working range (e.g., 15-35 L / s), the turbine speed can reach 2500-3500 rpm.

[0063] The generator stator windings are fixed to the inner wall of the housing and arranged opposite to the magnetically coupled rotor that rotates with the turbine. The rotor's rotation cuts magnetic field lines to generate three-phase alternating current, which is rectified by a rectifier bridge and smoothed by a filter capacitor before being input to the control circuit. This structure achieves an energy-autonomous mode of "powering as long as there is displacement," completely eliminating dependence on high-temperature lithium batteries.

[0064] 2. Control Circuit

[0065] Control circuit module 2 is encapsulated in a high-voltage, high-temperature resistant titanium alloy electronic compartment. Its main functions include power management and motor drive. It includes a DC-DC switching power supply module, which converts the wide-range DC voltage output from the generator (e.g., 20V-50V) into the stable voltage required by the system, such as +5V to supply the microcontroller (MCU) and +33V to supply the motor drive stage. An H-bridge drive circuit is used to connect the brushless DC motor 3. The microcontroller internally stores the encoding protocol of downhole measurement data (such as MWD pulse coding rules) and outputs PWM signals to control the forward and reverse rotation angle and speed of the motor according to external commands or preset logic.

[0066] 3. Brushless DC motor and magnetic engagement device

[0067] The brushless DC motor 3 serves as the power source, and its output shaft is connected to the input end of the magnetic drive assembly via a spline. The magnetic engagement device in the magnetic drive assembly employs magnetic coupling isolation technology. Its core structure includes an inner magnetic rotor, an outer magnetic rotor, and a non-magnetic isolation sleeve. The isolation sleeve is made of TA2 industrial pure titanium or a high-strength non-magnetic alloy, with a preferred wall thickness of 1.5-2.0 mm. It is fixed to the housing, completely physically isolating the motor cavity from the external sandy mud environment. The inner magnetic rotor is placed inside the isolation sleeve (motor cavity), and the outer magnetic rotor is placed outside the isolation sleeve (transmission cavity). Both have an even number of pairs (preferably 12 pairs) of sector-shaped permanent magnets embedded on their circumferential surfaces, arranged in an alternating N / S pole configuration. When the motor drives the inner magnetic rotor to rotate, the magnetic field penetrates the isolation sleeve. Based on the magnetic coupling principle of "opposite poles attract, like poles repel," it drives the outer magnetic rotor to rotate synchronously without contact, achieving a torque transmission efficiency of over 95%. This design fundamentally solves the problem of mud intrusion caused by dynamic seal failure, and significantly improves reliability under high sand content (sand content ≥3%) conditions.

[0068] 4. Reducer and self-resetting device

[0069] The output end of the magnetic engagement device is connected to a reducer, preferably with a reduction ratio of 120:1, used to reduce the high speed of the motor to the low speed and high torque required by the rotary valve. The output shaft of the reducer is rigidly connected to the inner shaft of the self-resetting device. Figure 3 As shown, the self-resetting device adopts an axially nested double-shaft structure. The inner shaft serves as the main transmission shaft, with dovetail grooves on its outer circumference, and two pairs of permanent magnets (preferably N52 grade neodymium iron boron, temperature resistance ≥200℃) with alternating N and S poles are fixedly installed. The outer shaft is coaxially fitted to the outside of the inner shaft and fixed to the housing; its inner circumference also has two pairs of permanent magnets with opposite polarities. In this embodiment, the number of magnetic pole pairs p=2. The magnets on the inner and outer shafts are fully aligned in the initial position (0° fully open), at which point the magnetic potential energy is lowest and the restoring torque is zero. According to the magnetic dipole interaction model, the restoring torque T varies with the rotation angle θ. The maximum working angle of the rotary valve rotor is designed. =45°, the corresponding electrical angle at this time =90°. Within this range, the restoring torque increases monotonically with the deflection angle. This means that when a power outage occurs, regardless of the rotor's position, the magnetic field will generate a deterministic restoring torque pointing towards the 0° position, driving the rotor to be forcibly reset to the fully open safe position, preventing a "pump stall" accident when restarting pumping.

[0070] 5. Rotary valve mechanism

[0071] like Figure 5 As shown, the rotary valve mechanism is located at the far end of the tool and includes a fixed stator and a rotating rotor. The stator is fixed to the housing and has several arc-shaped flow channel windows distributed circumferentially. The rotor is directly connected to the inner shaft of the self-resetting device and has blades corresponding to the stator windows. When the inner shaft drives the rotor to rotate, the overlapping area of ​​the rotor blades and the stator windows changes, thereby altering the flow resistance of the drilling fluid. The flow channels are fully open (low pump pressure) when the rotor is at 0°, and the throttling area is minimized (high pump pressure) when rotated to 45°. By controlling the reciprocating motion of the rotor, a recognizable pressure pulse sequence can be generated on the surface, enabling downhole data transmission.

[0072] Specifically, the maximum designed operating angle of the rotary valve rotor 7 is 45°; the number of pole pairs p of the permanent magnet in the self-resetting device 6 is related to the maximum operating angle. Satisfying Relationship: ≤ 90°;

[0073] When power is interrupted due to pump stoppage or displacement fluctuation, the restoring torque generated by the self-resetting device 6 increases monotonically with the deflection angle in the range of 0° to 45°, and the system has only one stable equilibrium position throughout the entire operating range.

[0074] Specifically, the rotary valve rotor has four blades, forming four mud flow channels, each with a central angle of 45° (i.e., 360° / 8). Furthermore, if the number of blades is eight, the maximum design operating angle of the rotary valve rotor is set to 22.5°. To maintain the same torque matching characteristics, the number of magnetic pole pairs p corresponding to the self-resetting device needs to be adaptively adjusted to four pairs.

[0075] In this embodiment, the core design of the self-resetting device lies in constructing a monostable magnetic potential energy field by coordinating a specific number of magnetic pole pairs with the maximum operating angle of the rotary valve, ensuring deterministic reset after power failure. The self-resetting device operates based on the principle of minimum magnetic reluctance. Let p be the number of permanent magnet pole pairs installed on the inner and outer rotating shafts, and θ be the mechanical rotation angle of the inner rotating shaft relative to the outer rotating shaft (shell). According to the magnetic dipole interaction model, the magnetic interaction torque T (i.e., the restoring torque) between the inner and outer rotating shafts can be approximately expressed as:

[0076]

[0077] Where θ is the mechanical rotation angle of the inner shaft relative to the outer shaft, and K>0 is a constant related to the magnet performance, air gap, and geometric dimensions.

[0078] Specifically, this embodiment sets the maximum design operating angle of the rotary valve rotor 7. =45°, number of pole pairs p=2. Under these parameters, the maximum electrical angle is =2 × 45° = 90°. Within the mechanical rotation angle range of 0° to 45°, the electrical angle varies within the range of [0°, 90°]. Within this interval, the sine function... The value of increases monotonically with increasing angle. Due to the presence of a negative sign, the restoring torque... The algebraic value of changes negatively with increasing angle. However, regarding the magnitude (amplitude) of the restoring torque... In terms of its properties, it increases monotonically with the increase of the deflection angle θ.

[0079] The further the rotor deviates from its equilibrium position, the stronger the reset driving force it receives. This ensures that even under conditions with high sand resistance, the rotor can still obtain the maximum reset driving force at its maximum opening position (45°), overcoming mechanical friction and reliably resetting.

[0080] Specifically, the system's equilibrium position occurs where the torque is zero, i.e., it satisfies... Within the mechanical rotation angle range of 0° to 45°, only (Right now This is one solution. Within the electrical angle interval [0°, 90°] Only There is a solution at this point. This means that within the physical space of mechanical rotation angles from 0° to 45°, there exists only one equilibrium point: θ = 0°. According to... When the rotor is disturbed and produces a positive deflection angle (θ>0), the torque τ<0 (reverse direction); when it produces a negative deflection angle (θ<0), the torque τ>0 (positive direction). This torque direction characteristic indicates that θ=0° is the stable equilibrium position (potential energy minimum point).

[0081] Specifically, the product of the number of magnetic pole pairs and the maximum working angle of the self-resetting device 6 is set to 90 degrees; at the maximum working angle position, the relative electrical angle between the inner and outer rotating shafts reaches 90 degrees, and the restoring torque generated by the permanent magnet self-resetting component increases monotonically with the increase of the angle within the stroke from 0 degrees to the maximum working angle.

[0082] Specifically, the maximum design operating angle of the rotary valve rotor The angle is set to 45°. The number of pole pairs p of the permanent magnet in the self-resetting device is set to 2 pairs (i.e., alternating N and S). At this time, the product of the number of pole pairs and the maximum operating angle... The angle is precisely set to 90 degrees. Under this specific setting, when the rotor rotates to its maximum working position of 45°, the relative electrical angle between the inner and outer shafts reaches exactly 90°. According to the aforementioned mechanical model, the restoring torque reaches its theoretical maximum value (sin90°=1) at this point. This design ensures the strongest reset capability at the extreme position where the driving force is most needed, and the restoring torque increases monotonically with the rotation angle from 0° to 45°, without directional ambiguity, achieving 100% reset reliability.

[0083] To demonstrate the superiority of this design, a comparative analysis of different schemes is presented below: Recommended schemes (2 pairs): As mentioned above, within the rotation range of 0° to 45°, the system electrical angle increases linearly from 0° to 90°, and the restoring torque... It increases monotonically, reaching its theoretical maximum value at the endpoint. This characteristic ensures the strongest reset capability even at the extreme positions where the driving force is most needed, with no directional ambiguity throughout the entire process and 100% reset reliability.

[0084] Comparative Example 1 (too few pole pairs, such as 1 pair): If p=1, then =45°, Only 70.7% of the maximum possible torque, which may lead to reset failure under conditions of high mud viscosity or bearing jamming.

[0085] Comparative Example 2 (too many pole pairs, such as 4 pairs): If p=4, then =180°, If the actual rotation angle slightly exceeds 45° (e.g., 46°) due to tolerance or vibration, then , If the torque direction is reversed, the system will be pushed to a pseudo-equilibrium point of 180° electrical angle (i.e. 90° mechanical angle), causing the rotary valve to jam and seriously threatening operational safety.

[0086] Specifically, the self-resetting device 6 adopts an axial nested structure, with the inner rotating shaft coaxially fitted inside the outer rotating shaft; the output shaft of the reducer 5 is rigidly connected to the inner rotating shaft, the inner rotating shaft serves as the main transmission shaft, and its outer circumferential surface serves as the mounting carrier for the permanent magnet.

[0087] Specifically, the outer rotating shaft is a cylindrical structure open at both ends, its outer wall fixed inside the tool housing by threaded connection or interference fit, serving as a stationary component. Its inner circumferential surface serves as the working surface of the magnetic yoke, and is machined with mounting grooves for installing permanent magnets. The inner rotating shaft is a solid or hollow shaft structure located within the cavity of the outer rotating shaft. The inner and outer rotating shafts are separated by sliding bearings or oil-free bushings (such as PTFE composite bushings), forming a controllable fit clearance. This clearance is the working air gap of the magnetic circuit; in this embodiment, a single-sided air gap value of 0.2mm-0.5mm is preferred. Within this clearance range, the rotational flexibility of the inner rotating shaft in the mud environment is ensured, while maintaining a high magnetic flux density and preventing the restoring torque from attenuating due to excessive magnetic reluctance. An internal spline hole is machined at the end of the reducer output shaft, and an external spline shaft is correspondingly machined at the front end of the inner rotating shaft. The two are connected by a spline joint and secured with an axial locking nut.

[0088] Specifically, the control circuit 2 includes a microcontroller and an H-bridge drive circuit, and is configured with predictive protection logic;

[0089] The microcontroller monitors the output voltage of the turbine generator 1 in real time. When the voltage is detected to be lower than the preset threshold and continues for a set time, it determines that the power supply is abnormal and triggers the safety reset process first, driving the rotary valve rotor 7 to return to the fully open position, thereby realizing active safety control before power failure.

[0090] Specifically, the microcontroller (MCU) is an industrial-grade microcontroller (such as the STM32 series or DSP controller) with a high-precision analog-to-digital converter (ADC) module and fast interrupt response capability. Its function is to process the voltage sampling signal in real time, run predictive protection algorithms, and output PWM control signals. The H-bridge drive circuit is a full-bridge inverter circuit composed of four power MOSFETs, connected to the brushless DC motor. The PWM signal output by the MCU drives the MOSFETs after opto-isolation, controlling the motor's forward rotation (adjusting valve position) or reverse rotation (resetting) by changing the conduction sequence, and also has a braking function. The voltage sampling circuit sets up a resistor divider network at the output terminal of the turbine generator 1, and after filtering out high-frequency noise through a low-pass filter, it is connected to the MCU's ADC pin for real-time monitoring of the generator output voltage. The energy storage circuit (a key configuration) is equipped with a large-capacity tantalum capacitor or supercapacitor bank at the power supply input of the control circuit. This energy storage circuit is designed to provide continuous operating power to the MCU and H-bridge drive circuit for at least 500ms to 1s after the generator output is interrupted. The predictive protection logic is stored in the MCU's non-volatile memory, and its specific execution steps are as follows:

[0091] The MCU uses an ADC to set a frequency (e.g., 1kHz) to... Sampling is performed, and a moving average filtering algorithm is used to eliminate instantaneous fluctuation interference to obtain the current effective voltage value. The MCU will With preset threshold (Typically set to 80% of the rated operating voltage) for comparison. If The system enters "early warning mode" and starts the debounce timer. If the set time... If the voltage remains below the threshold for 100ms (e.g., 100ms), it is considered a power supply abnormality (distinct from voltage drops caused by instantaneous displacement fluctuations). If the voltage recovers within the set time, the system continues to operate normally to avoid false triggering. Once the abnormality is determined, the MCU immediately triggers the highest priority non-maskable interrupt (NMI), suspending all current adjustment tasks (such as position closed-loop PID calculation, communication response, etc.) and forcibly jumping to the safety reset subroutine. The MCU calls the remaining energy in the energy storage circuit and outputs a reset control signal (such as a PWM wave with a preset duty cycle) to the H-bridge drive circuit. The H-bridge drive motor rotates in reverse, generating active driving torque, which assists the magnetic force of the self-reset device, forcibly driving the rotary valve rotor to move to the fully open position (0°).

[0092] Specifically, the present invention provides an analog decoding device for a self-generating rotary valve mud pulse generator, comprising:

[0093] Test box 9 is used to provide operating power to the pulse generator and output control command signals that are analog downhole encoded;

[0094] An infrared diffuse reflection photoelectric switch 10 is installed on the outside of the rotary valve stator 8 of the pulse generator. Its beam is directly facing the movement trajectory area of ​​the rotor blades. The photoelectric switch integrates a transmitter and a receiver. When a reflective surface exists within the detection distance, the receiver captures the reflected light and outputs a high level; otherwise, it outputs a low level.

[0095] The interface box 11 is electrically connected to the infrared diffuse reflection photoelectric switch 10 and is used to collect its output signal and perform level conversion and transmission.

[0096] The host computer 12 is communicatively connected to the interface box 11 and is used to receive signals, decode status, and record and store them.

[0097] Specifically, when the rotary valve rotor 7 rotates to the throttling position, the rotor blades enter the detection area of ​​the photoelectric switch, forming a reflective surface and outputting a high level; when the rotor is in the 0° fully open position, there are no blades blocking the reflection, resulting in no effective reflection and outputting a low level.

[0098] The high / low level sequence constitutes a simulated mud pressure pulse signal, which is used to verify the function of the pulse generator under normal pressure.

[0099] Specifically, the test box has a built-in adjustable DC regulated power supply, whose output voltage range covers the operating voltage range of the pulse generator turbine generator 1 (e.g., 24V DC - 36V DC), used to replace the downhole turbine generator and provide operating power for the control circuit of the pulse generator. The command generation module integrates an encoder chip or microcontroller to generate control commands that simulate those issued from the ground. This module is connected to the communication interface of the pulse generator via a cable, sending analog electrical signals such as "positive pulse test," "negative pulse test," or specific coded sequences (e.g., MCM encoding) to drive the rotary valve rotor to perform corresponding rotational actions. The infrared diffuse reflection photoelectric switch serves as a non-contact position sensor to capture the motion state of the rotary valve in real time. A diffuse reflection photoelectric sensor with adjustable detection distance (e.g., an industrial-grade sensor with an M18 or square shape) is selected. Its working principle is as follows: the transmitter emits an infrared modulated beam, which is diffusely reflected when it encounters an obstacle. The receiver detects the intensity of the reflected light and converts it into an electrical signal. The photoelectric switch is fixedly mounted on the outer wall of the rotary valve stator by a bracket, with its sensing probe pointing perpendicularly to the edge motion trajectory of the rotor blades. Adjust the sensor's sensitivity knob to set its effective detection distance to [value missing]. to (For example, 5mm to 20mm). The logic is as follows: when the rotor blade rotates to a position below the probe, the metal surface of the blade acts as an effective reflective surface, with a distance of less than... The sensor detects the presence of an object and outputs a high-level signal.

[0100] When the rotor blades rotate away, the area below the probe is either an empty air gap or a dark light-absorbing coating on the inner wall of the stator, with a distance greater than [missing information]. If the reflectivity is insufficient, the sensor determines that "there is no object" and outputs a low-level signal.

[0101] The interface box is responsible for signal acquisition, conditioning, and transmission, specifically including:

[0102] Level Conversion Unit: The signal voltage output by the photoelectric switch is typically an industrial level (such as 12V or 24V). The level conversion circuit inside the interface box converts this signal to a logic level compatible with the host computer (such as TTL 5V or RS232 level) to prevent damage to the data acquisition card due to excessive voltage.

[0103] Filtering and Shaping: The circuit integrates an RC low-pass filter and a Schmitt trigger to eliminate noise interference caused by the photoelectric switch jittering at the critical position, ensuring steep edges of the output signal and improving decoding accuracy.

[0104] The host computer runs dedicated decoding software and performs the following steps:

[0105] The square wave signal sequence transmitted from the interface box is read in real time via serial port or data acquisition card (DAQ). The width and spacing of the square wave are analyzed according to the preset encoding protocol.

[0106] High level detected: corresponds to blade blocking state, simulating downhole mud pressure increase (positive pulse) or decrease (negative pulse, depending on the specific rotary valve structure).

[0107] Low level detected: This corresponds to the blade not being blocked, and the simulated mud pressure returns to the normal baseline.

[0108] The software interface draws signal waveforms in real time and displays the decoded data (such as the current valve opening and encoding error rate). At the same time, it automatically stores the test data as a log file for subsequent analysis.

[0109] During the specific testing process: The test box is powered on, and the pulse generator control circuit is activated. The test box is operated to send a "throttling" command, causing the inner shaft to rotate the blades (e.g., to 45°). The blades enter the photoelectric switch detection area, the sensor outputs a high level, and the host computer displays "Pulse Start." The power to the test box is then cut off, simulating a power outage. The pulse generator automatically resets under the action of the magnetic self-reset device, the blades leave the detection area, the sensor outputs a low level, and the host computer displays "Pulse End / Valve Reset." By observing whether the falling edge of the waveform recorded by the host computer is smooth and whether there is any jamming or jitter, the power-off reset function and mechanical motion reliability of the pulse generator can be verified under normal pressure.

[0110] Specifically, the infrared diffuse reflection photoelectric switch 10 is a PNP type normally open output mode photoelectric switch with adjustable sensing distance and sensitivity, and its installation position corresponds to the throttling critical angle region of the rotary valve mechanism.

[0111] Specifically, the infrared diffuse reflection photoelectric switch is configured as a PNP type normally open output mode. "Normally open" means that in the sensor's natural state when no valid object is detected (i.e., the rotary valve rotor blades), its internal output transistor is in the off state, and the signal output line has a high impedance or low level relative to the negative terminal of the power supply; when an object is detected, the output transistor is saturated and conducts, and the signal output line outputs a high level (voltage value close to the power supply voltage). This output mode allows for a direct logical mapping between the sensor signal level and the rotary valve's operating state: a low level corresponds to the fully open position of the rotary valve (unobstructed), and a high level corresponds to the throttling position of the rotary valve (obstructed). This logic eliminates the need for polarity reversal processing on the host computer side, reducing decoding latency. The photoelectric switch has a sensitivity adjustment mechanism (usually a multi-turn potentiometer) for setting its action threshold. The threshold refers to the trigger voltage value of the comparator inside the sensor, and its physical meaning corresponds to the critical detection distance at which the sensor can reliably operate (…). When the object being measured is within a distance of the sensor probe... When the reflected light intensity exceeds a threshold, the sensor output flips. By adjusting the threshold, ambient light interference and stray reflections from background objects (such as the inner wall of the rotary valve stator) can be filtered out, ensuring that the sensor only responds to rotor blades within a specific distance. The threshold setting must satisfy the following distance constraints:

[0112]

[0113] in, This is the radial distance from the sensor probe to the inner wall of the stator (the background area without blades); This is the radial distance from the sensor probe to the surface of the rotor blade.

[0114] When setting it up specifically, adjust the sensitivity knob to achieve the critical detection distance. In and Between. For example, if the air gap The blade spacing is 20mm. If it is 5mm, then... The setting is 10mm to 15mm. This value ensures that the signal reliably flips when the blade rotates into the detection area, and when the blade leaves, the sensor considers the inner wall of the stator to be in a "no object" state, thus avoiding false triggering.

[0115] The photoelectric switch is precisely calculated so that the axial cross-sectional position of its optical axis centerline corresponds to the throttling critical angle region of the rotary valve mechanism. This refers to the angular range from when the rotary valve rotor starts rotating from its fully open position until its blade edge just enters the fluid flow channel and begins to produce an effective throttling effect. In this embodiment, this region is defined as the angular position where the leading edge of the rotor blade coincides with the edge of the stator flow channel, typically between 5° and 15°. The photoelectric switch is installed on the outside of the rotary valve stator, with its optical axis centerline aligned with the trajectory of the leading edge of the rotor blade at the throttling critical angle position.

[0116] Specifically, the present invention also provides an analog decoding method for an analog decoding device, comprising:

[0117] Step S1: Power is supplied to the pulse generator through the test box 9, and control command signals simulating downhole coding are output.

[0118] Specifically, the power output terminal of the test box is connected to the power input terminal of the pulse generator to simulate the power supply environment of a turbine generator. The test box outputs control command signals that simulate downhole encoding (such as MCM or PPM encoded signals), which are directly injected into the control circuit communication interface of the pulse generator via a cable.

[0119] Step S2: Drive the rotary valve rotor 7 to reciprocate between the fully open position and the maximum throttling position;

[0120] Specifically, the control circuit of the pulse generator receives the command signal, analyzes it, and drives the motor to rotate. After being reduced in speed and increased in torque by the reducer, the motor drives the rotary valve rotor to perform corresponding mechanical actions. These actions cause the rotor to reciprocate between the fully open position and the maximum throttling position, thereby simulating the opening and closing process of the downhole mud channel.

[0121] Step S3: The position status of the rotor blades is detected in real time using an infrared diffuse reflection photoelectric switch 10. When the rotor blades enter the detection area and form a reflective surface, a high-level signal is output, and when the rotor blades leave the detection area, a low-level signal is output.

[0122] Specifically, when the rotor blades rotate into the optical axis detection area of ​​the photoelectric switch, the blade surface acts as an effective reflective surface, diffusely reflecting infrared light back to the receiver, triggering the photoelectric switch to output a high-level signal. When the rotor blades leave the detection area, there is no effective reflective surface, the receiver receives no signal, the photoelectric switch resets, and outputs a low-level signal. These high and low-level signals are then converted and filtered by the interface box before being transmitted to the host computer.

[0123] In step S4, the host computer 12 reconstructs the received level sequence into a simulated mud pressure pulse waveform according to the mapping relationship that high level corresponds to throttling state and low level corresponds to fully open state, and calculates the pulse width and on / off response time.

[0124] Specifically, based on a preset mapping relationship, the received level sequence is reconstructed into a simulated mud pressure pulse waveform. Let the received signal voltage be V, and the preset software decision threshold be... .

[0125] when When the signal is high, it is mapped to a throttling state (simulating an increase or decrease in downhole pressure), and the reconstructed waveform amplitude is set to... .

[0126] when When the signal is low, it is mapped to the fully open state (simulating the downhole pressure baseline), and the reconstructed waveform amplitude is set to... .

[0127] Specifically, the software decision threshold The value is typically set to 50% to 70% of the sensor's high-level output voltage (for example, if the sensor outputs a 24V high level, then...). (It can be set from 12V to 16V). The function of this threshold is to eliminate noise interference on the signal transmission line and jitter in the critical state of the sensor, ensuring the robustness of the state judgment.

[0128] set up The moment when the signal level changes from low to high. This refers to the moment when the signal level transitions from high to low. Pulse width. The calculation formula is: To evaluate the electromechanical delay characteristics of the system, the on / off response time parameter is defined. On response time. The moment when control commands are issued from the test box From the moment the photoelectric switch detects rotor movement (i.e., the signal level first jumps to a high level) Time difference, closing response time This refers to the time difference from the moment a power interruption or reset command is issued until the moment the signal level transitions to a low level. It is calculated... and It can quantitatively evaluate the inertial delay of the motor drive system, the transmission efficiency of the reducer, and the reset speed of the magnetic self-resetting device, thereby completing a comprehensive verification of the dynamic performance of the pulse generator during the ground testing phase.

[0129] Specifically, step S4 further includes comparing the reconstructed analog waveform with the theoretical encoded waveform. If the level transition delay or duration deviation is detected to exceed a preset threshold, it is determined that the rotary valve is mechanically stuck or the control logic is abnormal.

[0130] Specifically, the host computer internally stores a standard encoding library corresponding to the control command signals issued by the test box in step S1. Based on the received command sequence, the host computer generates an ideal theoretical encoded waveform. This waveform is a standard square wave sequence, with its rising edge time strictly aligned with the command issuance time, and its pulse width strictly consistent with the preset encoding parameters. The host computer uses a timestamp alignment algorithm to synchronously align the reconstructed analog waveform and the theoretical encoded waveform on the time axis, and extracts the following feature parameters for quantitative comparison:

[0131] Jump delay bias Defined as the time difference between the level transition moment in the simulated waveform and the corresponding transition moment in the theoretical waveform. This parameter reflects the electromechanical response speed of the system.

[0132] Duration deviation Defined as the difference between the actual duration of the high-level pulse in the analog waveform and the theoretical pulse width, this parameter reflects the execution accuracy of the control logic.

[0133] The preset threshold includes the maximum allowable delay threshold ( ) and the maximum permissible pulse width deviation threshold ( The threshold is used to define normal error and fault state. The threshold represents the maximum permissible dynamic error range of the system under normal operating conditions, taking into account factors such as motor start-stop inertia, reducer backlash, and hysteresis. As a criterion for fault detection, it filters normal electromechanical transient fluctuations and accurately identifies abnormal faults. In this embodiment, based on the electromechanical characteristics of the pulse generator, the following maximum permissible delay threshold is set: The setting is 50ms to 200ms. If it exceeds this range, it indicates excessive rotor resistance or insufficient driving force. Maximum permissible pulse width deviation threshold. Set the value to ±10% of the theoretical pulse width or a fixed value of 20ms. If the value exceeds this range, it indicates a timing error in the control logic.

[0134] The host computer calculates the feature parameters in real time and executes the judgment logic based on the preset threshold:

[0135] If detected If the delay increases over multiple consecutive pulse cycles, it is determined to be mechanical jamming of the rotary valve. This is usually due to increased frictional torque caused by mud deposition, bearing wear, or magnet adsorption of iron filings, resulting in a delayed rotor motion response.

[0136] If detected However, if Δt is within the normal range, it is determined to be a control logic anomaly. This is usually due to crystal oscillator frequency drift, program malfunction, or incorrect control algorithm parameters, causing the duration of the motor drive signal to differ from the command.

[0137] Once an anomaly is detected, the host computer automatically marks the faulty waveform segment, generates a fault report, and issues an audible and visual alarm signal to prompt the operator to inspect or calibrate the pulse generator.

[0138] Specifically, the analog decoding method further includes:

[0139] The test box 9 outputs a simulated power supply voltage that decreases at a preset slope. The control circuit of the pulse generator is monitored to see if it triggers a safety reset process when the voltage drops to a threshold. Combined with the waveform response time recorded by the host computer, the reset reliability of the self-reset device under simulated power interruption conditions is verified.

[0140] Specifically, the programmable power module integrated inside the test box executes a voltage drop simulation program, outputting a simulated supply voltage V(t) that decreases at a preset slope. The preset slope k is defined as the rate at which the voltage decreases over time (unit: V / s). Its value is set based on the actual output characteristics of the downhole turbine generator under conditions of displacement fluctuation or pump shutdown.

[0141] Specifically, when simulating displacement fluctuations, the slope k can be set to a smaller value (e.g., 5V / s~10V / s) to simulate a gradual drop; when simulating a sudden pump stoppage, the slope k can be set to a larger value (e.g., 50V / s~100V / s) to simulate a rapid drop. The function of this parameter is to simulate real-world changes in the downhole power supply environment and to verify the response sensitivity of the control circuit under different voltage decay rates.

[0142] The control circuit of the pulse generator monitors the input voltage in real time and has a built-in undervoltage lockout threshold. . This is the critical voltage value for determining a power supply abnormality. When the power supply voltage is lower than this value, the control circuit determines that the energy is insufficient to maintain normal regulation functions, and must forcibly interrupt the current task and perform a reset operation. The value is typically set to 70% to 85% of the pulse generator's rated operating voltage. This setting avoids false triggering caused by normal voltage fluctuations while ensuring sufficient energy margin for performing a reset action before the capacitor's energy storage is depleted.

[0143] The host computer executes reliability verification logic by recording the time points and waveform changes during the voltage drop process: This indicates that the power supply voltage has dropped to a certain level. , This refers to the moment when the host computer receives the photoelectric switch signal and it transitions from a high level to a low level (i.e., the moment the rotor returns to the fully open position). Reset response time. Based on the design of the energy storage capacitor in the control circuit, a maximum allowable reset time threshold is set. (e.g., 500ms).

[0144] If the calculated result If the waveform displayed on the host computer successfully transitions to a low level and remains stable, the reset is considered reliable. This indicates that the control circuit successfully triggered the safety reset process, and the magnetic torque of the self-reset device effectively cooperated with the residual electrodynamic torque of the motor to complete the action.

[0145] like If the waveform does not change (remains at a high level), the reset is considered to have failed. This indicates potential issues such as insufficient energy storage, mechanical jamming, or insufficient magnetic force.

[0146] Specifically, this invention converts the kinetic energy of drilling fluid into electrical energy to drive the system via a turbine generator, achieving energy self-sufficiency. The magnetic engagement device utilizes the characteristic of magnetic fields penetrating non-magnetic isolation sleeves to achieve non-contact torque transmission, ensuring transmission efficiency while physically isolating sand-containing mud from the motor cavity, completely eliminating the risk of media intrusion caused by dynamic seal wear. The self-resetting device, based on the magnetic torque angle characteristics between the permanent magnets of the inner and outer rotating shafts, uses the restoring torque automatically generated by magnetic potential energy to drive the rotary valve rotor to reset to the fully open position when the active driving torque is lost due to power failure. This effectively prevents downhole pressure accidents caused by rotary valve closure and significantly improves the sealing life and intrinsic safety of the system.

[0147] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0148] The above description is merely a preferred embodiment of the present invention and is not intended to limit the 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 self-generating rotary valve mud pulse generator, characterized in that, include: Turbine generator, control circuit, brushless DC motor, magnetic drive assembly, and rotary valve mechanism; The turbine generator is installed in the drilling fluid flow channel, and its power output terminal is electrically connected to the control circuit to convert the kinetic energy of the drilling fluid into electrical energy and supply power to the control circuit. The control signal output terminal of the control circuit is electrically connected to the brushless DC motor and is used to drive the brushless DC motor to rotate. The output shaft of the brushless DC motor is connected to the input end of the magnetic drive assembly; The magnetic drive assembly includes a magnetic engagement device, a reducer, and a self-resetting device connected sequentially along the power transmission path. The magnetic meshing device includes an inner magnetic rotor and an outer magnetic rotor, which are separated by a non-magnetic isolation sleeve. The inner magnetic rotor is connected to the output shaft of the brushless DC motor, and the outer magnetic rotor is connected to the input shaft of the reducer. This is used to achieve non-contact torque transmission and isolate the motor cavity from the sand-containing mud environment. The output shaft of the reducer is connected to the inner rotating shaft of the self-resetting device; The self-resetting device includes an inner rotating shaft and an outer rotating shaft arranged coaxially, with the outer rotating shaft fixed to the housing; two pairs of permanent magnets with alternating N and S poles are fixed to the outer circumference of the inner rotating shaft and the inner circumference of the outer rotating shaft, respectively. The rotary valve mechanism includes a rotary valve stator and a rotary valve rotor. The rotary valve stator is fixedly installed, and the rotary valve rotor is connected to the inner rotating shaft of the self-resetting device.

2. The self-generating rotary valve mud pulse generator according to claim 1, characterized in that, The maximum designed operating angle of the rotary valve rotor is 45°; the number of pole pairs p of the permanent magnet in the self-resetting device is related to the maximum operating angle. Satisfying Relationship: ≤ 90°; When power is interrupted due to pump stoppage or displacement fluctuation, the restoring torque generated by the self-resetting device increases monotonically with the deflection angle in the range of 0° to 45°, and the system has only one stable equilibrium position throughout the entire operating range.

3. The self-generating rotary valve mud pulse generator according to claim 2, characterized in that, The product of the number of magnetic pole pairs of the self-resetting device and the maximum working angle is set to 90 degrees. At the maximum working angle position, the relative electrical angle between the inner and outer rotating shafts reaches 90 degrees, and the restoring torque generated by the permanent magnet self-resetting component increases monotonically with the increase of the angle within the stroke from 0 degrees to the maximum working angle.

4. The self-generating rotary valve mud pulse generator according to claim 3, characterized in that, The self-resetting device adopts an axial nested structure, with the inner rotating shaft coaxially fitted inside the outer rotating shaft; the output shaft of the reducer is rigidly connected to the inner rotating shaft, the inner rotating shaft serves as the main transmission shaft, and its outer circumferential surface serves as the mounting carrier for the permanent magnet.

5. A self-generating rotary valve mud pulse generator according to claim 4, characterized in that, The control circuit includes a microcontroller and an H-bridge drive circuit, and is equipped with predictive protection logic; The microcontroller monitors the output voltage of the turbine generator in real time. When the voltage is detected to be lower than the preset threshold and continues for a set time, it determines that the power supply is abnormal and triggers the safety reset process first, driving the rotary valve rotor to return to the fully open position, thereby realizing active safety control before power failure.

6. A simulation decoding device based on a self-generating rotary valve mud pulse generator according to any one of claims 1-5, characterized in that, include: The test box is used to provide operating power to the pulse generator and output control command signals that are analog downhole encoded. An infrared diffuse reflection photoelectric switch is installed on the outside of the rotary valve stator of the pulse generator. Its beam is directly facing the movement trajectory area of ​​the rotor blades. The photoelectric switch integrates a transmitter and a receiver. When a reflective surface exists within the detection distance, the receiver captures the reflected light and outputs a high level; otherwise, it outputs a low level. An interface box is electrically connected to the infrared diffuse reflection photoelectric switch and is used to collect its output signal and perform level conversion and transmission. The host computer is communicatively connected to the interface box and is used to receive signals, decode status, and record and store them. Specifically, when the rotary valve rotor rotates to the throttling position, the rotor blades enter the detection area of ​​the photoelectric switch, forming a reflective surface and outputting a high level; when the rotor is in the 0° fully open position, there are no blades blocking the light, no effective reflection, and outputting a low level. The high / low level sequence constitutes a simulated mud pressure pulse signal, which is used to verify the function of the pulse generator under normal pressure.

7. The analog decoding device according to claim 6, characterized in that, The infrared diffuse reflection photoelectric switch is a PNP type normally open output photoelectric switch with adjustable sensing distance and sensitivity, and its installation position corresponds to the throttling critical angle region of the rotary valve mechanism.

8. The analog decoding method according to claim 6, characterized in that, include: Step S1: Power is supplied to the pulse generator through the test box, and control command signals simulating downhole coding are output. Step S2: Drive the rotary valve rotor to reciprocate between the fully open position and the maximum throttling position; Step S3: The position of the rotor blades is detected in real time using an infrared diffuse reflection photoelectric switch. When the rotor blades enter the detection area and form a reflective surface, a high-level signal is output, and when the rotor blades leave the detection area, a low-level signal is output. In step S4, the host computer reconstructs the received level sequence into a simulated mud pressure pulse waveform based on the mapping relationship that high level corresponds to throttling state and low level corresponds to fully open state, and calculates the pulse width and on / off response time.

9. The analog decoding method according to claim 8, characterized in that, Step S4 further includes comparing the reconstructed analog waveform with the theoretical encoded waveform. If the level transition delay or duration deviation is detected to exceed a preset threshold, it is determined that the rotary valve is mechanically stuck or the control logic is abnormal.

10. The analog decoding method according to claim 9, characterized in that, The analog decoding method further includes: The test box outputs a simulated power supply voltage that decreases at a preset slope. The control circuit of the pulse generator is monitored to see if it triggers a safety reset process when the voltage drops to a threshold. Combined with the waveform response time recorded by the host computer, the reset reliability of the self-reset device under simulated power interruption conditions is verified.

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