A constant liquid level adaptive parameter adjustment variable frequency control method and system for an electric submersible pump

Abstract

The present application provides a kind of electric submersible pump constant liquid level adaptive parameter adjustment frequency conversion control method and system, it is related to oil and gas field artificial lifting technical field, the method includes S1: parameter pre-setting;S2: obtains dynamic liquid level estimated value and judges whether in control dead zone, if yes, then keep current frequency does not adjust conclusion;If not, then calculate deviation;S3: according to the size and direction of deviation, adaptive PID and fuzzy control are used to generate adjustment amount;S4: automatically adjust frequency adjustment step;S5: the frequency instruction generated is frequency limiting, current limiting check, and output frequency conversion instruction;S6: acquisition electric pump operating state and dynamic liquid level estimated value;S7: closed loop iteration, including repeating steps S1-S6, form closed loop feedback and iteration.The system is used to realize the above method, the present application is applicable to the dynamic liquid level accurate closed loop control of electric submersible pump under complex working condition, realizes energy saving optimization and working condition adaptation.

Description

Technical Field

[0001] This invention relates to the field of artificial lift technology in oil and gas fields, and in particular to a constant liquid level adaptive parameter adjustment frequency conversion control method and system for electric submersible pumps. Background Technology

[0002] Electric Submersible Pumps (ESPs) are one of the main pieces of equipment for artificial lift in oil and gas fields, widely used in medium- to high-yield oil wells. During ESP operation, the dynamic fluid level, i.e., the fluid depth within the annular space of the casing and oil well, is a key parameter reflecting the match between the well's fluid supply capacity and the ESP's discharge capacity. An excessively high dynamic fluid level may lead to insufficient fluid supply or even depletion, damaging the ESP unit; an excessively low dynamic fluid level indicates insufficient discharge capacity, affecting production. Therefore, achieving precise control of the dynamic fluid level is crucial for ensuring the efficient and safe operation of ESPs.

[0003] With the development of power electronics and variable frequency speed control technologies, variable frequency control has become a core means of maintaining constant liquid level and reducing energy consumption in electric submersible pumps (ESPs). By adjusting the input frequency of the ESP, the motor speed is changed, thereby regulating the pump's discharge capacity and maintaining the dynamic fluid level within the target range. However, in actual oil well production, parameters such as formation fluid supply capacity, water cut, and gas-liquid ratio change dynamically over time, and these changes are complex and difficult to model accurately, posing a significant challenge to the constant liquid level control of ESPs.

[0004] Existing variable frequency control technologies mostly employ control strategies with fixed PID parameters and fixed frequency adjustment step sizes. In practical applications, this approach suffers from the following core drawbacks: 1. Poor adaptability. Existing technologies typically use a fixed set of PID parameters (proportional coefficient Kp, integral coefficient Ki, derivative coefficient Kd) throughout the production process, which cannot match the dynamic changes in well water cut, gas-liquid ratio, and fluid supply capacity. When the well enters a high water cut phase, the gas-liquid ratio changes abruptly, or the formation fluid supply capacity decreases, the fixed-parameter control system cannot respond in time, easily leading to problems such as large fluctuations in the dynamic fluid level, control overshoot or undershoot, and in severe cases, frequent start-stop of the electric pump, affecting the oil production rate.

[0005] 2. Lack of range-based control. Existing technologies mostly use single-point control, setting a target dynamic fluid level and controlling the deviation to approach zero. This control mode lacks a target range and dead zone (insensitive zone), resulting in an overly sensitive pump frequency response. Even slight fluctuations in the dynamic fluid level near the target value trigger frequency adjustments, causing frequent pump frequency changes. Frequent frequency adjustments not only increase the switching losses of the frequency converter but also exacerbate the mechanical wear of the pump unit, significantly shortening the equipment's lifespan.

[0006] 3. Inadequate protection mechanisms. Existing technologies do not adequately incorporate protection mechanisms such as frequency limiting and current limiting during the control process. When the control command requires the pump frequency to continuously increase, the motor current may exceed the rated range, causing the motor to overload and burn out; when the command requires the frequency to continuously decrease, the pump's drainage capacity is insufficient, the dynamic liquid level continues to drop, eventually leading to pump cavitation and causing serious equipment accidents.

[0007] 4. Inappropriate adjustment step size. Existing technologies mostly use a fixed frequency adjustment step size, that is, each adjustment is made according to a preset fixed increment (such as 0.5Hz or 1.0Hz), which cannot adapt to different operating conditions. When the dynamic liquid level deviation is large, a fixed small step size results in an excessively slow adjustment speed and excessive time for the liquid level to return to the target range; while when the dynamic liquid level is close to the target value, a fixed large step size is prone to overshoot, causing the liquid level to oscillate repeatedly around the target value, resulting in unsatisfactory control effect.

[0008] To address the aforementioned issues, some existing technologies attempt to optimize variable frequency control using intelligent control algorithms such as fuzzy control and adaptive PID. However, these improvements still suffer from the following shortcomings: First, they are not integrated with the dynamic fluid level interval control depth, still relying on a single-point control mode; second, they fail to achieve self-tuning of the adjustment step size, making it impossible to adaptively adjust the step size according to changes in well conditions; and third, they do not fully consider the comprehensive impact of multiple operating parameters (gas-liquid ratio, water cut, fluid supply capacity, etc.) on the control strategy. Therefore, they still cannot effectively cope with the dynamic changes in the dynamic fluid level under complex well conditions.

[0009] Furthermore, existing technologies do not adequately address the handling mechanisms after inverter failures. When an inverter trips due to overvoltage, undervoltage, or overcurrent, most solutions require manual on-site troubleshooting and restarting, increasing maintenance costs and reducing the system's automation level.

[0010] Therefore, there is an urgent need for a constant liquid level adaptive parameter adjustment frequency conversion control method and system for electric submersible pumps to solve the above-mentioned technical problems. Summary of the Invention

[0011] The purpose of this invention is to provide a constant liquid level adaptive parameter adjustment variable frequency control method and system for electric submersible pumps. This system enables closed-loop control of the dynamic liquid level interval, automatic tuning of control parameters and adjustment step size, and features multiple amplitude limiting protections and fault self-recovery functions. This addresses the technical problems of existing technologies, such as poor adaptive capability, frequent frequency adjustments, inadequate protection, and unreasonable adjustment step size. The numerous technical effects of the preferred solutions among the many technical solutions provided by this invention are detailed below.

[0012] To achieve the above objectives, the present invention provides the following technical solution: The present invention provides a constant liquid level adaptive parameter adjustment frequency conversion control method for electric submersible pumps, comprising the following steps: S1: Parameter preset; S2: Obtain the estimated value of the dynamic liquid level and determine whether it is within the control dead zone. If yes, maintain the current frequency without adjustment; otherwise, calculate the deviation. S3: Based on the magnitude and direction of the deviation, adaptive PID and fuzzy control are used to generate the adjustment amount; S4: Automatically adjusts the frequency adjustment step size; S5: Perform frequency limiting and current limiting verification on the generated frequency command, and output the frequency conversion command; S6: Collect the operating status of the electric pump and the estimated value of the dynamic liquid level, and repeat steps S2-S6 to form a closed-loop feedback and iteration.

[0013] Furthermore, in step S1, the preset parameters include: The preset target dynamic liquid level range [Hd1-Hd2], control dead zone δ, electric pump frequency operating range [fmin-fmax], and motor current safe range [Imin-Imax] are defined.

[0014] Further, in step S2, obtaining the estimated dynamic liquid level and determining whether it is within the control dead zone specifically includes: Obtain the current dynamic liquid level estimate Hd, and calculate the deviation e between Hd and the target interval; If Hd is within the interval [Hd1+δ,Hd2-δ], then no adjustment is performed.

[0015] Furthermore, in step S3, the adaptive parameter tuning control law is generated as follows: based on the magnitude and direction of the deviation e, a control law combining adaptive PID and fuzzy control is used to generate the frequency adjustment command Δf.

[0016] Furthermore, in step S3, the adaptive parameter tuning control law is generated, specifically including: The adaptive PID control law automatically adjusts the proportional coefficient Kp, integral coefficient Ki, and derivative coefficient Kd based on the deviation e and the rate of change of deviation ec, thereby achieving parameter self-tuning. The fuzzy control law is based on a fuzzy rule base and generates a frequency adjustment quantity according to the deviation and the rate of change of the deviation. Reinforcement learning control laws optimize control strategies online through reward functions.

[0017] Furthermore, in step S4, the frequency adjustment step size is automatically adjusted according to the oil well conditions. When the deviation is large, a large step size is used for rapid adjustment, and when the deviation is small, a small step size is used for fine adjustment.

[0018] Furthermore, in step S4, specifically: The adjustment step size is automatically adjusted dynamically based on real-time data of gas-liquid ratio, water content, and liquid supply capacity. When the gas-liquid ratio is high and the liquid supply capacity is poor, use a small step size to avoid fluctuations. When the liquid supply capacity is stable but the deviation is large, a large step size is used for rapid adjustment.

[0019] Furthermore, in step S5, the limiting protection and frequency conversion output include frequency limiting and current limiting verification of the generated frequency command. If it exceeds the safe range, the command is cut off, and the final frequency command is output to the frequency conversion drive terminal of the electric submersible pump.

[0020] Furthermore, in step S5, Frequency limiting restricts the frequency command to the range of [fmin-fmax]; Current limiting restricts the motor current to the range of [Imin-Imax]; If the current approaches the upper limit, stop increasing the frequency to avoid overload; At the same time, a self-recovery mechanism for frequency converter faults is introduced, which automatically restores control after the fault is cleared.

[0021] An adaptive parameter-adjusting frequency conversion control system for constant liquid level of an electric submersible pump, used to implement the above method, includes: The parameter preset unit is used to preset control parameters; The dynamic liquid level input unit is used to obtain the estimated value of the dynamic liquid level; The deviation calculation unit is used to calculate the deviation between the estimated dynamic liquid level and the target range; An adaptive control unit is used to generate an adaptive parameter-tuning control law based on the deviation. The step size self-tuning unit is used to automatically adjust the frequency and step size according to the oil well operating conditions. The limiting protection unit is used to perform frequency limiting and current limiting verification on frequency commands. The frequency converter output unit is used to output the final frequency command to the frequency converter drive terminal of the electric submersible pump.

[0022] The electric submersible pump constant liquid level adaptive parameter adjustment frequency conversion control method provided by this invention adopts interval control and dead zone setting to avoid frequent frequency adjustment of the electric pump, significantly reduce dynamic liquid level fluctuations, and stabilize it within the target range; it realizes automatic tuning of control parameters and adjustment step size, perfectly adapting to the dynamic changes of oil well water cut, gas-liquid ratio, and liquid supply capacity; it introduces frequency limiting, current limiting, and fault self-recovery mechanisms to effectively suppress abnormal operating conditions such as pumping cavitation and overload, and extend equipment life; it is compatible with existing dynamic liquid level estimation systems and frequency conversion control cabinets, requiring no large-scale modification, with low deployment costs, and is easy to promote on a large scale. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart of the constant liquid level adaptive parameter adjustment frequency conversion control method for electric submersible pumps of the present invention; Figure 2 This is a schematic diagram of the adaptive parameter adjustment logic in the constant liquid level adaptive parameter adjustment frequency conversion control method for electric submersible pumps of the present invention; Figure 3 This is a schematic diagram of a constant liquid level adaptive parameter adjustment frequency conversion control system for an electric submersible pump. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0026] In the description of this invention, it should be understood that the terms "center," "side," "length," "width," "height," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and "side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0027] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] This invention provides a constant liquid level adaptive parameter adjustment frequency conversion control method for electric submersible pumps, comprising the following steps: S1: Parameter preset; S2: Obtain the estimated value of the dynamic liquid level and determine whether it is within the control dead zone. If yes, maintain the current frequency without adjustment; otherwise, calculate the deviation. S3: Based on the magnitude and direction of the deviation, adaptive PID and fuzzy control are used to generate the adjustment amount; S4: Automatically adjusts the frequency adjustment step size; S5: Perform frequency limiting and current limiting verification on the generated frequency command, and output the frequency conversion command; S6: Collect the operating status of the electric pump and the estimated value of the dynamic liquid level, and repeat steps S2-S6 to form a closed-loop feedback and iteration.

[0029] Figure 1 This is a flowchart of this embodiment, as shown below. Figure 1 As shown, the specific process includes: Start → Parameter Preset → Obtain Estimated Dynamic Liquid Level → Determine if within Control Dead Zone → →Yes→Keep the current frequency and do not adjust; →No→Calculate deviation→Generate adjustment amount using adaptive PID and fuzzy control→Adjustment step size self-tuning→Frequency / current limiting protection→Output frequency conversion command→Acquire operating status and dynamic liquid level→Closed-loop iteration until end.

[0030] Figure 2 This is a schematic diagram of the adaptive parameter tuning logic of the present invention, as shown below. Figure 2 As shown, this specifically includes: comparing the dynamic liquid level Hd with the target interval [Hd1, Hd2] → Hd > Hd2 (liquid level too low) → reduce frequency → liquid level rises → prevent cavitation; Hd < Hd1 (liquid level too high) → increase frequency → liquid level drops → prevent excessive liquid supply; No adjustment is made within the dead zone; Simultaneously, it combines multiple parameters such as gas-liquid ratio, water content, and liquid supply capacity for integrated analysis → adaptively adjusts the adjustment step size → passes through frequency limiting and current limiting protection → outputs the final frequency command.

[0031] The present invention will be further described in detail below with reference to specific embodiments.

[0032] S1: Parameter preset; Specifically, the preset control parameters include: preset target dynamic liquid level range [Hd1-Hd2], control dead zone δ, electric pump frequency operating range [fmin-fmax], and motor current safe range [Imin-Imax].

[0033] In this embodiment, the preset target dynamic liquid level range is [800m-1000m], the control dead zone is δ=50m, the frequency operating range is 30.0Hz-50.0Hz, and the current safety range is 20.0A-40.0A.

[0034] By setting a target dynamic liquid level range and a control dead zone, zoned control is achieved, avoiding frequent frequency adjustments of the electric pump. The fluctuation of the dynamic liquid level is significantly reduced and stabilized within the target range. By setting the operating frequency range and current safety range, a basis is provided for subsequent limiting protection, effectively suppressing abnormal operating conditions such as cavitation and overload.

[0035] Then, the estimated value of the dynamic liquid level is obtained in real time. If it is within the dead zone, no adjustment is made; if it deviates from the range, the adaptive PID automatically adjusts the parameters Kp, Ki, and Kd to generate a frequency adjustment command. See steps S2 and S3 for details.

[0036] S2: Obtain the estimated value of the dynamic liquid level and determine whether it is within the control dead zone. If yes, maintain the current frequency without adjustment; otherwise, calculate the deviation. The dynamic liquid level deviation calculation includes: obtaining the current dynamic liquid level estimate Hd, and calculating the deviation e between Hd and the target interval; if Hd is within the interval [Hd1+δ,Hd2-δ], no adjustment is performed.

[0037] By controlling the dead zone setting, no adjustment is performed when the dynamic liquid level is within the target range, avoiding frequent frequency adjustments of the electric pump, significantly reducing the fluctuation of the dynamic liquid level, and stabilizing it within the target range.

[0038] S3: Based on the magnitude and direction of the deviation, adaptive PID and fuzzy control are used to generate the adjustment amount; In this embodiment, the adaptive parameter tuning control law is generated as follows: based on the magnitude and direction of the deviation e, a control law combining adaptive PID and fuzzy control is used to generate the frequency adjustment command Δf. The control law combining adaptive PID and fuzzy control achieves automatic tuning of the control parameters to adapt to the dynamic changes in oil well water cut, gas-liquid ratio, and fluid supply capacity.

[0039] Specifically, the adaptive parameter tuning control law generation includes: an adaptive PID control law that automatically adjusts the proportional coefficient Kp, integral coefficient Ki, and derivative coefficient Kd based on the deviation e and the rate of change of deviation ec, achieving parameter self-tuning; a fuzzy control law that generates frequency adjustment based on the deviation and the rate of change of deviation using a fuzzy rule base; and a reinforcement learning control law that optimizes the control strategy online through a reward function. Through adaptive PID parameter self-tuning, fuzzy control rule base inference, and online optimization using reinforcement learning, automatic tuning of control parameters is achieved, significantly improving the adaptability to operating conditions and accommodating dynamic changes in oil well water cut, gas-liquid ratio, and fluid supply capacity.

[0040] S4: Automatically adjusts the frequency adjustment step size; Specifically, the frequency adjustment step size is automatically adjusted according to the oil well operating conditions. When the deviation is large, a large step size is used for rapid adjustment, and when the deviation is small, a small step size is used for fine adjustment. This achieves automatic tuning of the adjustment step size, adapts to the dynamic changes in oil well operating conditions, and improves the self-adaptive capability.

[0041] In this embodiment, the adjustment step size is dynamically adjusted based on real-time data of gas-liquid ratio, water cut, and fluid supply capacity. A small step size of 0.5Hz is used when the gas-liquid ratio is high and the fluid supply capacity is poor to avoid fluid level fluctuations. When the fluid supply capacity is stable but the deviation is large, a large step size of 1Hz-2Hz is used for rapid adjustment to return to the target range. Through multi-parameter fusion analysis of gas-liquid ratio, water cut, and fluid supply capacity, the adjustment step size is adaptively adjusted. Small step sizes are used for fine adjustment when the gas-liquid ratio is high and the fluid supply capacity is poor to avoid fluid level fluctuations. Large step sizes are used for rapid adjustment when the fluid supply capacity is stable but the deviation is large to quickly return to the target range. This achieves automatic adjustment of the adjustment step size to adapt to the dynamic changes in oil well conditions.

[0042] S5: Perform frequency limiting and current limiting verification on the generated frequency command, and output the frequency conversion command; Limiting protection and frequency conversion output include frequency and current limiting verification of the generated frequency command. If the frequency exceeds the safe range, the command is truncated, and the final frequency command is output to the frequency converter drive of the electric submersible pump. Through dual verification of frequency and current limiting, multiple protection mechanisms are introduced to prevent the electric pump from operating beyond its range, effectively suppressing abnormal operating conditions such as cavitation and overload, and extending the equipment life.

[0043] Among them: frequency limiting restricts the frequency command within the range of [fmin-fmax]; current limiting restricts the motor current within the range of [Imin-Imax]; if the current approaches the upper limit, frequency increase is stopped to avoid overload; at the same time, a frequency converter fault self-recovery mechanism is introduced, and control is automatically restored after the fault is cleared.

[0044] In this embodiment, when the frequency command exceeds 50.0Hz, it is automatically truncated to 50.0Hz; when the current approaches the upper limit of 40.0A, the frequency increase is stopped and the current frequency is maintained; through frequency limiting, current limiting and fault self-recovery mechanism, multiple limiting protection is achieved, which effectively suppresses abnormal operating conditions such as evacuation and overload, extends the equipment life, and after the frequency converter fault is eliminated, the system automatically restores closed-loop control without manual intervention.

[0045] S6: Collect the operating status of the electric pump and the estimated value of the dynamic liquid level, and repeat steps S2-S6 to form a closed-loop feedback and iteration.

[0046] By collecting the real-time operating status of the electric pump and the estimated dynamic liquid level, steps S2-S6 are repeated to form a closed-loop control.

[0047] This adaptive variable frequency control method for constant fluid level in electric submersible pumps (ESPs) achieves precise and stable closed-loop control of the dynamic fluid level based on adaptive parameter adjustment within the dynamic fluid level range, suppressing large fluctuations. It enables automatic tuning of control parameters and adjustment step sizes to adapt to dynamic changes in oil well conditions, enhancing its adaptive capability. Multiple protection mechanisms are introduced to prevent ESP operation beyond its range and suppress abnormal conditions such as cavitation and overload. It is compatible with existing dynamic fluid level estimation systems, requiring no large-scale modifications and facilitating large-scale deployment.

[0048] This embodiment also provides a constant liquid level adaptive parameter adjustment frequency conversion control system for electric submersible pumps, used to implement the above method. It is suitable for precise closed-loop control of the dynamic liquid level of electric submersible pumps under complex operating conditions, achieving energy-saving optimization and operating condition adaptation. Specifically, it includes: The parameter preset unit is used to preset control parameters; The dynamic liquid level input unit is used to obtain the estimated value of the dynamic liquid level; The deviation calculation unit is used to calculate the deviation between the estimated dynamic liquid level and the target range; An adaptive control unit is used to generate an adaptive parameter-tuning control law based on the deviation. The step size self-tuning unit is used to automatically adjust the frequency and step size according to the oil well operating conditions. The limiting protection unit is used to perform frequency limiting and current limiting verification on frequency commands. The frequency converter output unit is used to output the final frequency command to the frequency converter drive terminal of the electric submersible pump.

[0049] like Figure 3 The diagram shown is a system framework diagram of this embodiment. In the diagram, the components are: dynamic liquid level input unit → deviation calculation unit → main controller → step size self-tuning unit → amplitude limiting protection unit → frequency conversion output unit → electric submersible pump frequency conversion drive. Dynamic liquid level monitoring value → real-time feedback → dynamic liquid level input unit, forming a closed-loop control system.

[0050] This system can achieve closed-loop control of dynamic liquid level intervals, automatic tuning of control parameters and adjustment step size, multiple amplitude limiting protection and fault self-recovery, significantly improve the stability of dynamic liquid level control and the adaptability of operating conditions, effectively suppress problems such as cavitation, overload and frequent frequency adjustment, is compatible with existing systems, has low deployment cost, and is suitable for intelligent frequency conversion control of constant liquid level in electric submersible pumps under various complex operating conditions.

[0051] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A constant liquid level adaptive parameter adjustment frequency conversion control method for an electric submersible pump, characterized in that, Includes the following steps: S1: Parameter preset; S2: Obtain the estimated value of the dynamic liquid level and determine whether it is within the control dead zone. If yes, maintain the current frequency without adjustment; otherwise, calculate the deviation. S3: Based on the magnitude and direction of the deviation, adaptive PID and fuzzy control are used to generate the adjustment amount; S4: Automatically adjusts the frequency adjustment step size; S5: Perform frequency limiting and current limiting verification on the generated frequency command, and output the frequency conversion command; S6: Collect the operating status of the electric pump and the estimated value of the dynamic liquid level, and repeat steps S2-S6 to form a closed-loop feedback and iteration.

2. The constant liquid level adaptive parameter adjustment frequency conversion control method for electric submersible pumps according to claim 1, characterized in that... In step S1, the preset parameters include: The preset target dynamic liquid level range [Hd1-Hd2], control dead zone δ, electric pump frequency operating range [fmin-fmax], and motor current safe range [Imin-Imax] are defined.

3. The constant liquid level adaptive parameter adjustment frequency conversion control method for electric submersible pumps according to claim 1, characterized in that... In step S2, obtaining the estimated dynamic liquid level and determining whether it is within the control dead zone specifically includes: Obtain the current dynamic liquid level estimate Hd, and calculate the deviation e between Hd and the target interval; If Hd is within the interval [Hd1+δ,Hd2-δ], then no adjustment is performed.

4. The constant liquid level adaptive parameter adjustment frequency conversion control method for electric submersible pumps according to claim 1, characterized in that... In step S3, the adaptive parameter tuning control law is generated as follows: based on the magnitude and direction of the deviation e, a control law combining adaptive PID and fuzzy control is used to generate the frequency adjustment command Δf.

5. The constant liquid level adaptive parameter adjustment frequency conversion control method for electric submersible pumps according to claim 4, characterized in that... In step S3, the adaptive parameter tuning control law is generated, specifically including: The adaptive PID control law automatically adjusts the proportional coefficient Kp, integral coefficient Ki, and derivative coefficient Kd based on the deviation e and the rate of change of deviation ec, thereby achieving parameter self-tuning. The fuzzy control law is based on a fuzzy rule base and generates a frequency adjustment quantity according to the deviation and the rate of change of the deviation. Reinforcement learning control laws optimize control strategies online through reward functions.

6. The constant liquid level adaptive parameter adjustment frequency conversion control method for electric submersible pumps according to claim 1, characterized in that... In step S4, the frequency adjustment step size is automatically adjusted according to the oil well conditions. When the deviation is large, a large step size is used for rapid adjustment, and when the deviation is small, a small step size is used for fine adjustment.

7. The constant liquid level adaptive parameter adjustment frequency conversion control method for electric submersible pumps according to claim 6, characterized in that... In step S4, the specific steps are as follows: The adjustment step size is automatically adjusted dynamically based on real-time data of gas-liquid ratio, water content, and liquid supply capacity. When the gas-liquid ratio is high and the liquid supply capacity is poor, use a small step size to avoid fluctuations. When the liquid supply capacity is stable but the deviation is large, a large step size is used for rapid adjustment.

8. The constant liquid level adaptive parameter adjustment frequency conversion control method for electric submersible pumps according to claim 1, characterized in that... In step S5, the limiting protection and frequency conversion output include frequency limiting and current limiting verification of the generated frequency command. If it exceeds the safe range, the command is cut off and the final frequency command is output to the frequency conversion drive terminal of the electric submersible pump.

9. The constant liquid level adaptive parameter adjustment frequency conversion control method for electric submersible pumps according to claim 8, characterized in that... In step S5, Frequency limiting restricts the frequency command to the range of [fmin-fmax]; Current limiting restricts the motor current to the range of [Imin-Imax]; If the current approaches the upper limit, stop increasing the frequency to avoid overload; At the same time, a self-recovery mechanism for frequency converter faults is introduced, which automatically restores control after the fault is cleared.

10. A constant liquid level adaptive parameter adjustment frequency conversion control system for an electric submersible pump, characterized in that: To implement the method according to any one of claims 1-9, comprising: The parameter preset unit is used to preset control parameters; The dynamic liquid level input unit is used to obtain the estimated value of the dynamic liquid level; The deviation calculation unit is used to calculate the deviation between the estimated dynamic liquid level and the target range; An adaptive control unit is used to generate an adaptive parameter-tuning control law based on the deviation. The step size self-tuning unit is used to automatically adjust the frequency and step size according to the oil well operating conditions. The limiting protection unit is used to perform frequency limiting and current limiting verification on frequency commands. The frequency converter output unit is used to output the final frequency command to the frequency converter drive terminal of the electric submersible pump.

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