Abstract: This paper analyzes the specific factors contributing to the low operating efficiency of current oil pumping unit motors, focusing on energy conservation and improved energy utilization. By analyzing the operating state of the oil pumping unit and considering the characteristics of switched reluctance motors, an energy-saving control system based on a switched reluctance motor is designed, using the ARMS3C2410 as the core control component. This system solves the problems of torque detection and follow-up control and stroke adjustment in the oil pumping unit, resulting in a high-efficiency and stable switched reluctance motor control system. The entire system effectively improves the overall energy utilization rate of the oil pumping unit system and has significant potential for widespread application. Keywords : Energy saving, switched reluctance motor, oil pumping unit, ARMS3C2410 [align=center]Energy-saving Control System of Oil-pumping Unit Based on Switched Reluctance Motor Tian Jingwen1,2, Wu Hao1, Gao Meijuan2 1 School of Information Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China [email protected] 2 Beijing Union University, No. 97, North Fourth Ring Road East, Chaoyang District, Beijing 100101, China [email protected] [/align] Abstract : The low efficiency of the motor of the current oil-pumping unit is analyzed from the point of energy saving and increasing the utilization efficiency of energy source. An energy-saving control system for oil-pumping unit is designed which uses a switched reluctance motor based on an ARMS3C2410 central processor via the characteristics of the switched reluctance motor and oil-pumping unit. It solves the following problem: monitoring the torque of the oil-pumping unit This system controls the motor and adjusts the stroke of the oil pumping unit. It is a stable control system for switched reluctance motors and has high efficiency. The system can enhance the utilization efficiency of power and has a good future for popularization. Keywords : Energy-saving, Switched reluctance motor, Oil pumping unit, ARMS3C2410 1 Introduction Currently, the widely used oil pumping units in China are of two types: beam pumping units and beamless pumping units, with beam pumping units being the main type. Most of the motors used in these units are Y-series motors. Beam pumping units use direct-start under load, requiring a large starting torque, and the motor starting current is 6-8 times the rated current. The motors used to meet the starting requirements have a large power output, while the torque required during operation is relatively small, with over 90% of the motors operating at a load rate below 50%. For a long time, the motors used in oil pumping units have mostly been operating under light load, with extremely low load rates, large power losses, and serious energy waste. Pumping unit power consumption accounts for a large proportion of oilfield production electricity consumption, with electricity costs accounting for about one-third of the total oilfield development cost. 2. Pumping Unit Energy-Saving System Currently, major oilfields prioritize energy conservation and efficiency improvement to reduce production costs, aiming to minimize the power consumption of pumping units' motors. Based on the operating characteristics of pumping units, to achieve this goal, the motor should possess the following characteristics: low motor loss; maintaining a high power factor and efficiency over a wide load variation range; smooth, stepless speed adjustment with a wide speed range to adapt to different well conditions and their supply and drainage relationships; and the ability to achieve soft start, reducing the impact on the pumping unit during startup and lowering the capacity of the selected motor and transformer. A motor meeting these requirements must have a high power factor and efficiency, and also ensure good coordination between the pumping unit's motor, rod, and pump system, improving system efficiency. Therefore, developing motors with these characteristics has become an inevitable trend, and the switched reluctance speed-regulating motor is a new type of motor with these characteristics. It has a simple and reliable structure, high system efficiency, large starting torque, many controllable parameters, and simple control mode. Its comprehensive performance is outstanding. It is the most ideal power system for pumping units at present. Its research and development and production have milestone significance for energy-saving production in oil fields. In order to solve the energy-saving problem of pumping unit system, in addition to the need for high power factor and efficiency of motor, smooth speed adjustment over a wide range, soft start and system protection function, it is also necessary to consider the optimization of pumping unit motor power, solve the problem of "big horse pulling small cart", and improve the efficiency of the whole system. Oil wells that have entered the middle and late stages of exploitation often have low pump filling coefficient and the pumping unit stroke is difficult to determine, which is also a relatively difficult problem to solve [1]. Switched reluctance speed control motor is a new type of speed control motor system. It is another stepless speed control system that has gradually matured internationally after AC variable frequency speed control motor. Its emergence has greatly improved the efficiency of pumping units. This paper designs an energy-saving control system for pumping units based on switched reluctance motor based on ARMS3C2410 embedded system. It mainly solves the energy-saving problem from the perspective of motor and pumping unit [2]. 3 System Design This paper designs the entire energy-saving control system based on the ARMS3C2410 embedded system. The principle block diagram is shown in Figure 1: [align=center] Figure 1 System Principle Diagram[/align] 3.1 Pumping Unit Torque Measurement The pumping unit (as shown in Figure 2) drives the sucker rod by the up-and-down movement of the pump head, sucking crude oil into the pipeline network on the ground. The pumping unit requires a large amount of power to lift the oil column during the upstroke, while it can fall freely without power during the downstroke. In order to make the load uniform, a certain balancing mechanism, such as a balance block, is usually provided. The total load torque formed on the motor shaft is the sum of the oil well load torque and the balancing torque. Figure 3 shows the load curve of a typical pumping unit. As can be seen from Figure 3, the load of the pumping unit fluctuates periodically. To make the pumping unit motor work optimally at every point of the load curve, and at the same time make the power output of the pumping unit follow the load change in each cycle, the torque curve of the pumping unit can be stored in the system. The control system can calculate the corresponding torque by detecting the crank angle, thereby changing the motor control and adjusting the speed to match the actual output torque, avoiding the problem of "overpowered motor," and greatly saving energy. Simultaneously, the pumping unit operates smoothly, significantly reducing mechanical wear, lowering the failure rate, and increasing production. Theoretically, this motor control method has been proven to reduce energy consumption by up to 60% compared to ordinary motors, demonstrating significant energy savings. 3.2 Steplessly Adjustable Stroke Rate Stroke rate refers to the number of times the pumping unit's rod moves up and down per minute, indicating the operating status of the pumping unit. In actual testing, one stroke of the pumping unit rod's up and down movement is considered one stroke, and the stroke rate is expressed as the number of times the up and down strokes (stroke refers to the vertical distance between the top dead center and bottom dead center of the pumping unit's rod) are completed per minute. The variation in pumping unit stroke frequency affects the amplitude and frequency of the load change at the pumping unit's suspension point. The amplitude and frequency of this load change determine the service life of equipment such as the pumping unit rod string, motor, pumping unit, and pump, as well as the energy consumption per well and the efficiency of the mechanical pumping system. This, in turn, determines the pump inspection and overhaul cycle and the production cost per ton of oil. Furthermore, multiple tests have demonstrated that adjusting the stroke frequency has a significant impact on the production of high-yield wells, but little impact on the production of wells with insufficient fluid supply. From the above analysis, it is clear that studying the variation law of pumping unit stroke frequency is of great significance for reducing energy consumption, especially production costs. Oil wells entering the mid-to-late stages of production often face the problem of low pumping unit fill factor, making it difficult to determine the pumping unit stroke frequency. Moreover, the fill factor changes continuously with the dynamic fluid level, making it a challenge to tightly integrate the pumping unit fill factor with the stroke frequency to form a closed-loop control. The intelligent control system designed in this paper can track changes in the well's fluid output, determine the magnitude of the fill factor, and provide signals to increase or decrease the stroke frequency, adjusting the pumping unit stroke frequency to significantly save energy. The switched reluctance motor control system can ensure stepless adjustment of the stroke rate between 0.8-8 strokes/min, ensure reasonable pump filling degree, and reduce pump dry running. At the same time, corresponding safety monitoring is set up. When there is well jamming, rod breakage or other faults, the system stops pumping and alarms. The system design enables the pumping unit to work in the best working state, prolongs the pump inspection cycle, and reduces the energy consumption of the pumping unit [3][4][5]. 3.3 Motor control strategy The switched reluctance motor is a relatively new type of motor that has developed rapidly since the 1970s. Unlike traditional AC motors (asynchronous motors and synchronous motors), the switched reluctance motor (SR motor) adopts a stator and rotor double salient pole iron core structure, and only installs each phase excitation winding on the stator. Its working principle is to make the rotor position tend to the position of minimum magnetic resistance, so that the motor rotates. Based on the operating characteristics of the pumping unit and the operating characteristics of the switched reluctance motor, this paper designs a fuzzy control strategy for the speed control of the motor and the serious nonlinear characteristics of the motor. For specific speed control methods, due to the characteristics of the motor itself, this paper designs low-speed fixed-angle current chopping control-high-speed variable-angle voltage chopping control. When the motor is running at low speed, due to the small rotational electromotive force, the current peak value is large. Using fixed-angle current occupancy control can effectively protect the power switching devices and reduce torque pulsation. When the motor is running at high speed, due to the large rotational electromotive force, the current is small. By adjusting the PWM wave voltage, the average phase voltage is changed, and the waveform and peak value of the current are effectively adjusted, so that the motor output is maximized, the operation is stable, and the noise is small. Due to the characteristics of SR motor, it is desirable to place the winding current waveform in the rising segment of the inductance as much as possible during operation. Since the current establishment process and the freewheeling disappearance process require a certain amount of time, the shorter the time corresponding to the energized area when the speed increases, the more the current waveform lags. This can be corrected by adjusting the switching conduction angle. Under this working mode, the speed and torque adjustment range is large, and the motor performance is good at both high and low speeds. Several control methods have their own advantages and disadvantages. The combined application is conducive to taking advantage of their respective advantages and giving full play to their respective advantages, so that the motor has good performance indicators in a wide speed range [6][7]. 4 Motor Control System 4.1 Power Converter The power converter is a key part of energy transmission in the SRD system, playing a role in controlling the switching on and off of the windings, and is also a major factor affecting the system's performance-price ratio. An ideal SRD power converter should meet the following design requirements: using as few main switching elements as possible to reduce system cost, and being able to feed energy back to the power supply to avoid system losses. The system can be modulated by the main switching devices to effectively control the magnitude of the phase winding current. The power circuit should have the ability to rapidly increase the phase winding current with the smallest possible delay. The system should minimize losses as much as possible to ensure that the power supply voltage is provided to the motor phase windings as much as possible. Topology design is one of the key aspects of SR motor power converter design. Various main circuit structures have emerged to address the issue of handling the magnetic energy of the discharge winding. This paper studies and develops a new type of power converter circuit with low-power switching devices based on the asymmetric bridge circuit. The schematic diagram of the power converter is shown in Figure 4. [align=center] Figure 4 Power Converter Circuit[/align] This power converter retains all the advantages of the bridge circuit and meets the conditions that an ideal power converter should possess. In two-phase operation, the A-phase and C-phase windings will not conduct simultaneously, nor will the B-phase and D-phase windings conduct simultaneously. Therefore, their currents will not overlap, ensuring that the current flowing through each main switching device at any given time is only the current of one phase winding. Thus, in the traditional asymmetrical half-bridge structure, phases A and C, and phases B and D, can each share a single main switch, reducing the number of switching devices in the entire circuit by two, significantly saving costs and reducing the control complexity. In summary, this simplified circuit scheme retains the advantages of the asymmetrical half-bridge design while minimizing the number of switching devices, improving cost-effectiveness. 4.2 D/A Conversion and Low-Speed ​​Chopper Circuit When the switched reluctance motor (SRM) operates at low speed, the motor angular velocity ω is very small, and the winding current increases rapidly. To protect the power switching elements and the motor, and to simultaneously achieve high efficiency, high output, and low torque ripple, amplitude modulation chopping is required during low-speed operation. The chopping current limit value is issued by the ARM. Since the ARM controller itself does not have a D/A unit, an adjustable duty cycle PWM signal needs to be converted into a corresponding analog voltage signal through an external conversion circuit. This system uses the ARM's general-purpose timer 1 to generate an adjustable duty cycle PWM signal, which, after buffering, filtering, and amplification, yields a stable 0-5V analog voltage signal. The D/A conversion circuit is shown in Figure 5. The obtained voltage is converted into current. A chopper current-limiting input is given to one end of the chopper circuit, and the measured winding current is given to the other end, as shown in Figure 6. [align=center] Figure 6 Chopper Circuit[/align] 4.3 The PWM voltage is controlled within the θ[sub]on[/sub]-θ[sub]off[/sub] conduction range, so that the power switch operates in PWM mode, with a fixed pulse period T and an adjustable duty cycle T[sub]1[/sub]/T. Within T[sub]1[/sub], a positive voltage is applied to the winding, and within T[sub]2[/sub], zero voltage is applied. Changing the duty cycle will change the average winding voltage U, thereby indirectly changing the magnitude of the phase winding current, thus achieving speed and torque regulation. This paper outputs the required PWM pulse width modulation wave through a timer. 4.4 Position Detection and Angle Control The position sensor related circuit has two parts: the position sensor input circuit and the position signal processing and angle subdivision circuit. It mainly completes the functions of position signal processing and stator-rotor relative position angle subdivision. This paper adopts photoelectric type, and the research object is pole SRM. [align=center] Figure 7 Relative position of photoelectric sensor Figure 8 Measurement signal of sensor[/align] 4.4 Fuzzy control strategy Due to the significant nonlinearity of the switched reluctance motor system, the simple PID control algorithm cannot fully adapt to a wide range when the adjustment range is very wide, resulting in the system not obtaining good dynamic characteristics. Therefore, fuzzy control is introduced into the switched reluctance motor speed regulation system. The strong robustness of fuzzy control can effectively solve the nonlinearity of the switched reluctance motor. Based on the fundamental theory of fuzzy control, the analysis of fuzzy control for switched reluctance motors is as follows: 5. Conclusion As a new type of motor with broad market potential, the switched reluctance speed-regulating motor has been successfully applied to oil pumping units, serving as an energy-saving option for oilfield pumping units and providing a solid foundation for cost savings and increased production in oilfields. After multiple improvements tailored to specific field conditions, it can adapt to the actual requirements of oilfield operations, and its excellent comprehensive performance is increasingly attracting widespread attention. Based on the ARMS3C2410, this paper designs an energy-saving control system for oil pumping units based on switched reluctance motors, focusing on solving problems such as torque detection and tracking and stroke adjustment. For the operating characteristics of the motor, a fuzzy control strategy and a low-speed fixed-angle current chopper control—high-speed variable-angle voltage chopper control method are proposed. Simultaneously, if faults such as phase loss, overcurrent, or undervoltage occur during system operation, the system will automatically protect itself. The entire system scheme is feasible and can effectively improve the efficiency of oil pumping units, increase the safety factor, and achieve significant energy savings, with very long-term economic benefits and practical significance. By fully utilizing and exploring its potential characteristics and further improving the system, we can make a greater contribution to energy conservation and efficiency improvement in oil fields. References [1] Dai Yudong. Application of SRD in oil pumping wells [J]. Liaoning Chemical Industry. 2004, 33 (2) [2] Wu Jianhua. Design and application of switched reluctance motor [M]. Beijing: China Standards Press, 2000 [3] Lu Xiaojun, Wang Xuefeng. Application of switched reluctance speed control motor in oil pumping unit [J]. Petroleum Mining Machinery. 2006, 35 (4) [4] Liu Diji. Switched reluctance speed control motor [M]. Machinery Industry Press. 1994 [5] Wang Xiaojun. Research on speed control system of switched reluctance motor [MA]. Northwestern Polytechnical University. 2006, 3 [6] Sun Changchun. New design of switch reluctance motor control system [J]. Science and Technology Information Development and Economy. 2005, 15 [7] Wang Honghua. Speed ​​control technology of switched reluctance motor [M]. Machinery Industry Press, 1995 [8] Cui Jianfeng. Design and research of speed regulation system of switched reluctance motor [MA]. Northwestern Polytechnical University. 2005, 3 [9] Chen Hao. Research on speed regulation system of switched reluctance motor [J]. Journal of Instrumentation. 2001, 22 (3) [10] Song Wenchao, Lin Yong. Speed ​​regulation system of switched reluctance motor [J]. Coal Science and Technology. 2001, 29 (9) [11] Chen Xin, Zheng Hongtao, Jiang Jingping. Fuzzy control system of switched reluctance motor based on angle control [J]. Power Electronics Technology. 2004.4 [12] Wang Xiang. Research on the characteristics of switch reluctance motor control system based on fuzzy control rules [J]. China Science and Technology Information. 2006, 16