Power limiting circuit and method for electric workover rig

Abstract

The invention discloses a power limiting circuit and method for an electric workover rig, and relates to the technical field of electric workover rigs, the circuit comprises an operational amplification controller, an MOS tube circuit and a power element circuit, the power element circuit obtains motor real-time torque and motor real-time rotating speed, and the operational amplification controller is further connected with a motor of the electric workover rig. The operational amplification controller is used for acquiring a motor torque target value and a motor rotating speed target value, determining a correction value by using the fuzzy PID controller according to the motor real-time torque, the motor real-time rotating speed, the motor torque target value and the motor rotating speed target value, and feeding back the correction value to a motor of the electric workover rig; according to the application, the operational amplification controller, the MOS tube circuit and the power element circuit are arranged, so that the reasonability of power limitation of the electric workover rig can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of electric workover rigs, and in particular to a power limiting circuit and method for an electric workover rig. Background Art

[0002] With the advancement of motor technology, electric workover rigs are gradually replacing traditional internal combustion engine equipment. This requires more sophisticated technical means for the control and management of motors, especially power control under high load and unstable working conditions. Advances in battery technology, such as the development of lithium-ion batteries, have enabled electric workover rigs to achieve higher energy density and longer battery life. However, battery characteristics (such as charging and discharging rates, temperature effects, etc.) need to be effectively managed through power limiting methods to avoid overcharging or overdischarging, as well as to extend the battery life. The operating environment of the oil and gas industry is complex and safety is of paramount importance. Limiting rates can prevent equipment from operating under overload conditions and reduce the risk of failures and accidents. The development of compliant safety standards has also promoted the development of power management technology. With the development of sensors and real-time monitoring technology, the working status of electric workover rigs can be monitored in real time, including parameters such as current, voltage, temperature and load. These data provide the basis for the formulation of power limiting strategies. Modern electric workover rigs are usually equipped with high-performance control systems that optimize power output through algorithms and control strategies. These systems can dynamically adjust the power of the motor according to different working conditions to ensure the efficiency and stability of the system. As environmental protection requirements increase, electric equipment (compared to traditional fuel-driven equipment in oilfield operations) is gaining more and more attention. Power limiting strategies can help reduce energy consumption, reduce carbon emissions, and improve economic benefits, becoming an important part of the industry's transformation. Well repair operations often involve complex processes, such as the up and down movement of downhole equipment and changes in loads, requiring the power limiting system to respond quickly and adapt to various working conditions to ensure the reliability and efficiency of the operation. With the promotion of intelligent and automated technologies, electric well repair rigs are increasingly dependent on automated control systems during operation, and the demand for power limiting solutions has become more complex and diverse. Summary of the invention

[0003] The purpose of the present application is to provide a power limiting circuit and method for an electric workover rig, which can improve the rationality of the power limiting of the electric workover rig.

[0004] To achieve the above objectives, this application provides the following solutions:

[0005] In a first aspect, the present application provides a power limiting circuit for an electric workover rig, comprising: an operational amplifier controller, a MOS tube circuit, and a power element circuit;

[0006] The operational amplifier controller, the MOS tube circuit and the power element circuit are all connected to a power supply;

[0007] The power element circuit and the MOS tube circuit are both connected to the operational amplifier controller;

[0008] The power element circuit is connected to the motor of the electric workover machine; the power element circuit is used to obtain the real-time torque and real-time speed of the motor;

[0009] The operational amplifier controller is connected to the input component; the operational amplifier controller is also connected to the motor of the electric workover machine; the operational amplifier controller is used to obtain the motor torque target value and the motor speed target value, and determine the correction amount using a fuzzy PID controller according to the motor real-time torque, the motor real-time speed, the motor torque target value and the motor speed target value, and feed the correction amount back to the motor of the electric workover machine.

[0010] Optionally, the electric workover rig power limiting circuit further includes: a power supply;

[0011] The power supply is connected to the operational amplifier controller, the MOS tube circuit and the power element circuit respectively.

[0012] Optionally, the operational amplifier controller is a MCS-51 single chip microcomputer series, and the model of the operational amplifier controller is 80C51.

[0013] Optionally, the x1 pin of the operational amplifier controller is used as a target value input terminal and is connected to the input component;

[0014] The x2 pin of the operational amplifier controller is used as an actual value feedback terminal and is connected to the motor of the electric workover machine;

[0015] The p1 pin of the operational amplifier controller is connected to the first end of the MOS tube circuit;

[0016] The p2 pin of the operational amplifier controller is connected to the second end of the MOS tube circuit;

[0017] The do+ pin of the operational amplifier controller is connected to the second end of the MOS tube circuit and is connected to the positive electrode of the power supply as a first DC input terminal;

[0018] The do-pin of the operational amplifier controller, the second end of the MOS tube circuit and the first end of the power element circuit are connected, and connected to the negative electrode of the power supply as a second DC input end;

[0019] The g1 pin of the operational amplifier controller is connected to the second end of the power element circuit;

[0020] The g2 pin of the operational amplifier controller is connected to the third end of the power element circuit;

[0021] The g3 pin of the operational amplifier controller is connected to the fourth end of the power element circuit;

[0022] The g4 pin of the operational amplifier controller is connected to the fifth end of the power element circuit;

[0023] The g5 pin of the operational amplifier controller is connected to the sixth end of the power element circuit;

[0024] The g6 pin of the operational amplifier controller is connected to the seventh end of the power element circuit.

[0025] Optionally, the MOS transistor circuit includes: a first MOS transistor, a second MOS transistor, a first capacitor, a second capacitor and an inductor;

[0026] The gate of the first MOS tube serves as the first end of the MOS tube circuit;

[0027] The gate of the second MOS tube serves as the second end of the MOS tube circuit;

[0028] The source of the first MOS tube and the drain of the second MOS tube are connected to the first end of the inductor;

[0029] The second end of the inductor is connected to the first end of the first capacitor to serve as the third end of the MOS tube circuit;

[0030] The second end of the first capacitor, the source of the second MOS transistor and the first end of the second capacitor are connected to serve as the fourth end of the MOS transistor circuit;

[0031] The drain of the first MOS tube is connected to the second end of the second capacitor, serving as the fifth end of the MOS tube circuit, and is connected to the eighth end of the power element circuit.

[0032] Optionally, the power element circuit includes: a first power element, a second power element, a third power element, a fourth power element, a fifth power element and a sixth power element;

[0033] The cathode of the first power element is connected to the anode of the fourth power element, and the ninth end of the power element circuit is connected to the first phase signal of the motor of the electric workover machine;

[0034] The cathode of the second power element is connected to the anode of the fifth power element, and the ninth terminal of the power element circuit is connected to the second phase signal of the motor of the electric workover machine;

[0035] The cathode of the third power element is connected to the anode of the sixth power element, and the ninth end of the power element circuit is connected to the third phase signal of the motor of the electric workover machine;

[0036] The cathode of the fourth power element, the cathode of the fifth power element and the cathode of the third power element are connected as a first end of the power element circuit;

[0037] The gate of the first power element serves as the second end of the power element circuit;

[0038] The gate of the second power element serves as the third terminal of the power element circuit;

[0039] The gate of the third power element serves as the fourth terminal of the power element circuit;

[0040] The gate of the fourth power element serves as the fifth terminal of the power element circuit;

[0041] The gate of the fifth power element serves as the sixth terminal of the power element circuit;

[0042] The gate of the sixth power element serves as the seventh terminal of the power element circuit;

[0043] The anode of the first power element, the anode of the second power element, and the anode of the third power element are connected to serve as an eighth terminal of the power element circuit.

[0044] Optionally, the first power element, the second power element, the third power element, the fourth power element, the fifth power element and the sixth power element are all power tubes.

[0045] In a second aspect, the present application provides a power limiting method for an electric workover machine, the power limiting method for an electric workover machine is applied to the power limiting circuit for the electric workover machine, and the power limiting method for an electric workover machine includes:

[0046] Get the motor torque target value and the motor speed target value;

[0047] Get the real-time torque and speed of the motor;

[0048] The correction amount is determined by using a fuzzy PID controller according to the motor real-time torque, the motor real-time speed, the motor torque target value and the motor speed target value;

[0049] The correction amount is fed back to the motor of the electric workover rig.

[0050] Optionally, the correction amount is determined by using a fuzzy PID controller according to the real-time torque of the motor, the real-time speed of the motor, the target value of the motor torque and the target value of the motor speed, including:

[0051] Determine the torque error value according to the motor real-time torque and the motor torque target value;

[0052] Determine the speed error value according to the real-time speed of the motor and the target speed value of the motor;

[0053] According to the torque error value and the speed error value, the torque correction value is determined by using the fuzzy PID controller;

[0054] The torque correction value is converted into a rotational speed frequency, and the rotational speed frequency is determined as the correction amount.

[0055] Optionally, the torque error value is the difference between the real-time torque of the motor and the target torque value of the motor; the speed error value is the difference between the real-time speed of the motor and the target speed value of the motor.

[0056] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0057] The present application provides a power limiting circuit and method for an electric well repair machine, including: an operational amplifier controller, a MOS tube circuit and a power element circuit; the operational amplifier controller, the MOS tube circuit and the power element circuit are all connected to a power supply. The power element circuit and the MOS tube circuit are both connected to the operational amplifier controller. The power element circuit is connected to the motor of the electric well repair machine; the power element circuit is used to obtain the real-time torque of the motor and the real-time speed of the motor. The operational amplifier controller is connected to the input component; the operational amplifier controller is also connected to the motor of the electric well repair machine. The operational amplifier controller is used to obtain the motor torque target value and the motor speed target value, and according to the motor real-time torque, the motor real-time speed, the motor torque target value and the motor speed target value, the fuzzy PID controller is used to determine the correction amount, and the correction amount is fed back to the motor of the electric well repair machine. The present application can improve the accuracy of the power limiting of the electric well repair machine by setting the operational amplifier controller, the MOS tube circuit and the power element circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0059] Figure 1 This is a power limiting circuit diagram of an electric workover machine in one embodiment of the present application. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0061] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0062] The diesel-driven workover rig is driven by a traditional diesel engine. Through the mechanical structure, the power of the diesel engine is transmitted to the load. When the load is blocked by shaft locking, stuck rotation, pipe jamming, etc., the output of the diesel engine is continuous. When the output power of the diesel engine is less than the maximum torque that the load can bear, the equipment is blocked; when the output power of the diesel engine is greater than the maximum torque that the load can bear, it will cause equipment damage or accidents. In this case, the operator can only slow down the diesel engine or disengage the clutch and disconnect the power input end. There is a time difference, which is a test for the operator's comprehensive quality and reaction. Some companies install torque sensors in the mechanical transmission part to detect the torque of the load in real time. When there is a blockage and the maximum real-time torque of the load exceeds the torque protection setting value, an audible and visual alarm is issued to remind the operator that the load is blocked or faulty. This can also play a certain protective role. Since the alarm signal is only a reminder and the input power cannot be disconnected in time, the operator can only disconnect the power input. In this way, there will be a time difference, causing equipment damage or accidents. Therefore, in an exemplary embodiment, a power limiting circuit for an electric well repair machine is provided, which controls and monitors the power output and load input in real time; when the load is working, the system works according to the parameters set in this application, and requests the output signal, output power, speed, and torque to the power output end. The current, voltage, torque, and speed of the input and output ends are monitored in real time; when the monitored torque, current, and speed of the load end increase or decrease within the set parameter range of this application, the system adjusts the torque, current, and speed of the power output end to always let the input power follow the output power demand; when the monitored torque, current, and speed of the load end increase or decrease beyond the set parameter range of this application, the system cuts off the power input to protect the system. The technical terms involved in this embodiment include:

[0063] Dynamic load prediction: It is necessary to accurately predict the load changes during the well repair process in real time to ensure that the power distribution can adapt to the needs under different working conditions.

[0064] Power distribution and management: How to intelligently distribute the power of batteries and motors to meet operational needs while preventing overload, including charging and discharging management strategies.

[0065] Battery capacity and life: Control power output to suit the capacity and health of the battery, and prevent rapid battery degradation due to excessive power output.

[0066] Temperature control: Power limitation needs to take into account the temperature of the motor and battery to avoid overheating, which affects performance and safety under high temperature conditions.

[0067] Real-time monitoring and feedback control: Use sensors and control systems to achieve real-time monitoring of current, voltage, load, etc., so as to implement feedback control and adjust power output in time.

[0068] Respond to emergencies: Develop fast-response power limiting strategies to respond to sudden heavy loads, motor blockages, or other abnormal situations, and reduce power in a timely manner to ensure safe operation of the equipment.

[0069] Support for multiple working modes: How to achieve power limits in different working modes, such as drilling, workover, unloading, etc., to ensure flexibility and adaptability under various working conditions.

[0070] Energy saving and efficiency optimization: While limiting power, try to optimize energy usage, improve the energy efficiency of the overall system, reduce energy consumption, and improve economy.

[0071] System integration and coordinated control: Ensure the effective integration and coordination of the power limiting system with other systems (such as control systems, monitoring systems, etc.).

[0072] Safety and Compliance: Ensure that the power limit design complies with relevant safety standards and regulations to prevent safety incidents caused by equipment failure.

[0073] like Figure 1As shown, a power limiting circuit for an electric well repair machine is provided, including: an operational amplifier controller, a MOS tube circuit and a power element circuit. The operational amplifier controller, the MOS tube circuit and the power element circuit are all connected to a power supply. The power element circuit and the MOS tube circuit are all connected to the operational amplifier controller. The power element circuit is connected to the motor of the electric well repair machine. The power element circuit is used to obtain the real-time torque and real-time speed of the motor. The operational amplifier controller is connected to the input component. The operational amplifier controller is also connected to the motor of the electric well repair machine. The operational amplifier controller is used to obtain the motor torque target value and the motor speed target value, and according to the motor real-time torque, motor real-time speed, motor torque target value and motor speed target value, the correction amount is determined by using a fuzzy PID controller, and the correction amount is fed back to the motor of the electric well repair machine. MOS tube is a semiconductor three-terminal device that uses electric field effect to control its current size, and many characteristics and application directions are similar to triodes. This device is not only small in size, light in weight, low in power consumption, and long in life, but also has the advantages of high input impedance, low noise, good thermal stability, and strong radiation resistance, and is widely used, especially in large-scale integrated circuits. MOS tube circuits are mainly used as electronic switches in circuits. They have fast switching speeds and can achieve switching frequencies of hundreds to hundreds of thousands of times per second. Power component circuits include capacitors, inductors, resistors, and isolation transformers to power MOS tubes.

[0074] The power limiting circuit of the electric workover machine also includes a power supply, which is respectively connected to the operational amplifier controller, the MOS tube circuit and the power element circuit.

[0075] The operational amplifier controller is of the MCS-51 single-chip microcomputer series, and the operational amplifier controller model is 80C51.

[0076] The x1 pin of the operational amplifier controller is used as a target value input terminal and is connected to the input component.

[0077] The x2 pin of the operational amplifier controller is used as an actual value feedback terminal and is connected to the motor of the electric workover machine.

[0078] The p1 pin of the operational amplifier controller is connected to the first end of the MOS tube circuit.

[0079] The p2 pin of the operational amplifier controller is connected to the second end of the MOS tube circuit.

[0080] The do+ pin of the operational amplifier controller is connected to the second end of the MOS tube circuit and is connected to the positive electrode of the power supply as a first DC input terminal.

[0081] The do-pin of the operational amplifier controller, the second end of the MOS tube circuit and the first end of the power element circuit are connected to serve as a second DC input end connected to the negative electrode of the power supply.

[0082] The g1 pin of the operational amplifier controller is connected to the second end of the power element circuit.

[0083] The g2 pin of the operational amplifier controller is connected to the third terminal of the power element circuit.

[0084] The g3 pin of the operational amplifier controller is connected to the fourth end of the power element circuit.

[0085] The g4 pin of the operational amplifier controller is connected to the fifth terminal of the power element circuit.

[0086] The g5 pin of the operational amplifier controller is connected to the sixth end of the power element circuit.

[0087] The g6 pin of the operational amplifier controller is connected to the seventh terminal of the power element circuit.

[0088] The MOS tube circuit includes: a first MOS tube, a second MOS tube, a first capacitor, a second capacitor and an inductor.

[0089] The gate of the first MOS tube serves as the first end of the MOS tube circuit.

[0090] The gate of the second MOS tube serves as the second end of the MOS tube circuit.

[0091] The source of the first MOS tube and the drain of the second MOS tube are connected to the first end of the inductor.

[0092] The second end of the inductor is connected to the first end of the first capacitor to serve as the third end of the MOS tube circuit.

[0093] The second end of the first capacitor, the source of the second MOS tube and the first end of the second capacitor are connected to serve as the fourth end of the MOS tube circuit.

[0094] The drain of the first MOS tube is connected to the second end of the second capacitor, serving as the fifth end of the MOS tube circuit, and connected to the eighth end of the power element circuit.

[0095] The power element circuit includes: a first power element, a second power element, a third power element, a fourth power element, a fifth power element and a sixth power element.

[0096] The cathode of the first power element is connected to the anode of the fourth power element, and the ninth end of the power element circuit is connected to the first phase signal of the motor of the electric well repair machine.

[0097] The cathode of the second power element is connected to the anode of the fifth power element, and the ninth end of the power element circuit is connected to the second phase signal of the motor of the electric well repair machine.

[0098] The cathode of the third power element is connected to the anode of the sixth power element, and the ninth end of the power element circuit is connected to the third phase signal of the motor of the electric well repair machine.

[0099] The cathode of the fourth power element, the cathode of the fifth power element and the cathode of the third power element are connected as a first end of the power element circuit.

[0100] The gate of the first power element serves as the second end of the power element circuit.

[0101] The gate of the second power element serves as the third terminal of the power element circuit.

[0102] The gate of the third power element serves as the fourth terminal of the power element circuit.

[0103] The gate of the fourth power element serves as the fifth terminal of the power element circuit.

[0104] The gate of the fifth power element serves as the sixth terminal of the power element circuit.

[0105] The gate of the sixth power element serves as the seventh terminal of the power element circuit.

[0106] The anode of the first power element, the anode of the second power element, and the anode of the third power element are connected to serve as an eighth terminal of the power element circuit.

[0107] The first power element, the second power element, the third power element, the fourth power element, the fifth power element and the sixth power element are all power tubes.

[0108] Specifically, this embodiment includes a target value input terminal, an actual value feedback terminal, an operational amplifier controller, a motor signal feedback, a power element, a MOS tube, a DC input and an electronic circuit. The principle description and action relationship are as follows:

[0109] Control the operation of the motor, mainly controlling the speed and forward and reverse rotation of the motor. The system adopts an adaptive PID control algorithm to ensure the normal operation of the system output and the motor. This algorithm not only has the strong anti-interference of the controller, but also has the high-precision advantage of PID control and has strong control capabilities. The system uses a rotary transmitter and a photoelectric encoder to collect the output torque of the system motor end and the speed of the motor, and calculate the torque error value and the speed error change rate. The error value is then adjusted by the fuzzy PID controller, and the torque correction value is converted into the corresponding speed frequency. At the same time, it is fed back to the motor to adjust the speed of the motor to achieve smooth control of the system output torque. For example: the load requires a torque of 1000Nm, the motor accelerates from zero, and the motor end feeds back the real-time torque. When the real-time torque reaches the required torque, the motor runs at a constant speed, for example, the motor is just 800 rpm. When the load torque drops from 1000Nm to 800Nm, the motor end signal is fed back to the actual value feedback processing, and the operational amplifier controls the motor speed to increase to more than 800 rpm, so that the load end torque is constant at 1000Nm. On the contrary, when the load torque increases from 800Nm to 1000Nm, the motor-end signal is fed back to the actual value feedback processing, and the operational amplifier controls the motor speed to drop to less than 800 rpm, so that the load-end torque is constant at 1000Nm. If the load torque disappears and the torque increases exponentially, the control system will cut off the output and sound and light alarm, so that the operator can start the equipment after maintenance.

[0110] The power limiting circuit of the electric workover machine provided in this embodiment uses motor signal feedback to feed back data to the actual value feedback terminal, converts the electrical signal into a data signal, and outputs the result after comparing the operational amplifier controller with the manually set threshold value, so as to monitor the power usage of the electric workover machine in real time and ensure that the power is within the design range.

[0111] According to the comparison between the motor operating conditions, the thresholds set in advance by humans and the actual values ​​collected by the operational amplifier controller, load analysis is carried out according to the operating conditions, and the power requirements under different working conditions are evaluated to ensure that the power configuration of the equipment is reasonable; a current limiting device is set through the input signal terminal and the operational amplifier controller to prevent damage to the equipment due to excessive current; temperature sensors are installed inside the motor and the operational amplifier controller to monitor the temperature of the motor and related components to prevent malfunctions caused by overheating; the operational amplifier controller controls the starting current when the motor starts to avoid instantaneous high-power shocks; when it is detected that the power or current exceeds the set range, the power is automatically cut off or the power is reduced; a short-circuit protection device is configured to immediately cut off the power in the event of a short circuit to ensure the safety of the equipment; temperature, faults, etc. are fed back by the motor signal and realized through the actual value feedback terminal, the operational amplifier controller and the target input terminal: once the temperature exceeds the safe range, the system automatically alarms and cuts off the power to prevent damage to the equipment due to overheating; a fault detection and alarm system is implemented to provide timely feedback on the equipment status for easy maintenance; a regular inspection and maintenance system is formulated to ensure that the equipment is in good operating condition and potential problems are discovered in a timely manner.

[0112] In another embodiment, a power limiting method for an electric workover machine is provided. The power limiting method for an electric workover machine is applied to the power limiting circuit for the electric workover machine. The power limiting method for an electric workover machine includes:

[0113] Step 1: Get the motor torque target value and the motor speed target value.

[0114] Step 2: Get the real-time torque and speed of the motor.

[0115] Step 3: Determine the correction amount using the fuzzy PID controller according to the motor real-time torque, the motor real-time speed, the motor torque target value and the motor speed target value.

[0116] Step 4: Feedback the correction amount to the motor of the electric workover rig.

[0117] Step 3 includes: determining a torque error value according to the real-time torque of the motor and the target torque value of the motor. Determining a speed error value according to the real-time speed of the motor and the target speed value of the motor. Determining a torque correction value using a fuzzy PID controller according to the torque error value and the speed error value. Converting the torque correction value into a speed frequency, and determining the speed frequency as a correction amount.

[0118] The torque error value is the difference between the motor real-time torque and the motor torque target value. The speed error value is the difference between the motor real-time speed and the motor speed target value.

[0119] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0120] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A power limiting circuit for an electric workover rig, characterized in that: include: Operational amplifier controller, MOS tube circuit and power component circuit; The operational amplifier controller, the MOS tube circuit and the power element circuit are all connected to a power supply; The power element circuit and the MOS tube circuit are both connected to the operational amplifier controller; The power element circuit is connected to the motor of the electric workover machine; the power element circuit is used to obtain the real-time torque and real-time speed of the motor; The operational amplifier controller is connected to the input component; the operational amplifier controller is also connected to the motor of the electric workover machine; the operational amplifier controller is used to obtain the motor torque target value and the motor speed target value, and determine the correction amount using a fuzzy PID controller according to the motor real-time torque, the motor real-time speed, the motor torque target value and the motor speed target value, and feed the correction amount back to the motor of the electric workover machine.

2. The power limiting circuit of the electric workover rig according to claim 1, characterized in that: The electric workover rig power limiting circuit further includes: a power supply; The power supply is connected to the operational amplifier controller, the MOS tube circuit and the power element circuit respectively.

3. The power limiting circuit of the electric workover rig according to claim 2, characterized in that: The operational amplifier controller is a MCS-51 single-chip microcomputer series, and the operational amplifier controller model is 80C51.

4. The power limiting circuit of the electric workover rig according to claim 3, characterized in that: The x1 pin of the operational amplifier controller is used as a target value input terminal and is connected to the input component; The x2 pin of the operational amplifier controller is used as an actual value feedback terminal and is connected to the motor of the electric workover machine; The p1 pin of the operational amplifier controller is connected to the first end of the MOS tube circuit; The p2 pin of the operational amplifier controller is connected to the second end of the MOS tube circuit; The do+ pin of the operational amplifier controller is connected to the second end of the MOS tube circuit and is connected to the positive electrode of the power supply as a first DC input terminal; The do-pin of the operational amplifier controller, the second end of the MOS tube circuit and the first end of the power element circuit are connected, and are connected to the negative electrode of the power supply as a second DC input end; The g1 pin of the operational amplifier controller is connected to the second end of the power element circuit; The g2 pin of the operational amplifier controller is connected to the third end of the power element circuit; The g3 pin of the operational amplifier controller is connected to the fourth end of the power element circuit; The g4 pin of the operational amplifier controller is connected to the fifth end of the power element circuit; The g5 pin of the operational amplifier controller is connected to the sixth end of the power element circuit; The g6 pin of the operational amplifier controller is connected to the seventh end of the power element circuit.

5. The power limiting circuit of the electric workover rig according to claim 4, characterized in that: The MOS tube circuit comprises: a first MOS tube, a second MOS tube, a first capacitor, a second capacitor and an inductor; The gate of the first MOS tube serves as the first end of the MOS tube circuit; The gate of the second MOS tube serves as the second end of the MOS tube circuit; The source of the first MOS tube and the drain of the second MOS tube are connected to the first end of the inductor; The second end of the inductor is connected to the first end of the first capacitor to serve as the third end of the MOS tube circuit; The second end of the first capacitor, the source of the second MOS transistor and the first end of the second capacitor are connected to serve as the fourth end of the MOS transistor circuit; The drain of the first MOS tube is connected to the second end of the second capacitor, serving as the fifth end of the MOS tube circuit, and is connected to the eighth end of the power element circuit.

6. The power limiting circuit of the electric workover rig according to claim 5, characterized in that: The power element circuit comprises: a first power element, a second power element, a third power element, a fourth power element, a fifth power element and a sixth power element; The cathode of the first power element is connected to the anode of the fourth power element, and the ninth end of the power element circuit is connected to the first phase signal of the motor of the electric workover machine; The cathode of the second power element is connected to the anode of the fifth power element, and the ninth terminal of the power element circuit is connected to the second phase signal of the motor of the electric workover machine; The cathode of the third power element is connected to the anode of the sixth power element, and the ninth end of the power element circuit is connected to the third phase signal of the motor of the electric workover machine; The cathode of the fourth power element, the cathode of the fifth power element and the cathode of the third power element are connected as a first end of the power element circuit; The gate of the first power element serves as the second end of the power element circuit; The gate of the second power element serves as the third terminal of the power element circuit; The gate of the third power element serves as the fourth terminal of the power element circuit; The gate of the fourth power element serves as the fifth terminal of the power element circuit; The gate of the fifth power element serves as the sixth terminal of the power element circuit; The gate of the sixth power element serves as the seventh terminal of the power element circuit; The anode of the first power element, the anode of the second power element, and the anode of the third power element are connected to serve as an eighth terminal of the power element circuit.

7. The power limiting circuit of the electric workover rig according to claim 6, characterized in that: The first power element, the second power element, the third power element, the fourth power element, the fifth power element and the sixth power element are all power tubes.

8. A method for limiting power of an electric workover rig, characterized in that: The electric workover rig power limiting method is applied to the electric workover rig power limiting circuit according to any one of claims 1 to 7, and the electric workover rig power limiting method comprises: Get the motor torque target value and the motor speed target value; Get the real-time torque and speed of the motor; The correction amount is determined by using a fuzzy PID controller according to the motor real-time torque, the motor real-time speed, the motor torque target value and the motor speed target value; The correction amount is fed back to the motor of the electric workover rig.

9. The method for limiting the power of an electric workover rig according to claim 8, characterized in that: According to the motor real-time torque, motor real-time speed, motor torque target value and motor speed target value, the fuzzy PID controller is used to determine the correction amount, including: Determine the torque error value according to the motor real-time torque and the motor torque target value; Determine the speed error value according to the real-time speed of the motor and the target speed value of the motor; According to the torque error value and the speed error value, the torque correction value is determined by using the fuzzy PID controller; The torque correction value is converted into a rotational speed frequency, and the rotational speed frequency is determined as the correction amount.

10. The power limiting method of an electric workover rig according to claim 9, characterized in that: The torque error value is the difference between the real-time torque of the motor and the target torque value of the motor; the speed error value is the difference between the real-time speed of the motor and the target speed of the motor.

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