An Experimental Study on Microcomputer Control of Pump Controlled Motor Systems

Pump controlled motor electrohydraulic servo systems are much used in circumstances where high power drive is needed. This kind of system has the advantage of energy-saving. But, it also has some defects that have to be improved. Microcomputer control of a pump controlled motor electrohydraulic servo system is studied. A PID controller is first adopted on the closed loop control system, and experimental results are obtained. Then, a model reference adaptive controller is designed and realised on the same system applying a single board microcomputer. Experimental results show that the dynamic properties of the adaptive control system is much better than those of the PID system under different inertia load conditions.

Lubrication characteristics of external return spherical hinge pair of axial piston pump or motor under combined action of inclination and offset distance

External return mechanism is a mechanical structure applied to axial piston pumps.To study its lubrication characteristics,the Reynolds equation applied to an external return spherical hinge pair was deduced based on the vector equation of relative-motion velocity of the external return spherical hinge pair under the influence of external swash plate inclination and offset distance.The results show that the total friction,axial leakage flow,and maximum value of the maximum oil-film pressure increase with increasing pump-shaft speed and decrease with increasing offset distance in one working cycle when the external-swash-plate inclination is constant.However,the varying offset distance has little effect on the axial leakage flow.The maximum value of the maximum oil-film pressure decreases with increasing external-swash-plate inclination and the total leakage flow increases with increasing external-swash-plate inclination in one working cycle when the offset distance is constant.It can be seen that the abovementioned parameters are important factors that affect the lubrication characteristics of external return spherical hinge pairs.Therefore,the complex effects of different coupling parameters should be comprehensively considered in the design of the external return mechanism.

Design on Vibration Monitoring and Fault Diagnosis System of Large Water Pump Motor

Large water pump motor,whose operation decides the reliability of the whole production line,plays a very important role.Therefore,its online condition monitoring can help companies better know its operation,process fault analysis and protection.The essay mainly studies and designs large water pump motor′s real time vibration monitoring and fault diagnosis system.The essay completes the systems project design,the establishment of the system and performance test.Eddy-currentsensor,XM-120 vibration module,XM-320 axial translation module,XM-362 temperature module,XM-360 process amount module and XM-500 gateway module are used to measure the axial vibration and displacement of main motors.Laboratory tests prove that the system can meet the requirements of motor vibration monitoring.

LMI Approach to Robust H_∞/H_2 Controller Design with Regional Poles Constraint of a Pump-Motor System

The time domain guideposts requirements of a pump-motor system is transfered into a series of constraints which express the robust performance upper bound and regional poles limits of the closed loop system. Then the servo system control problem is transferred into the problem of robust performance optimizing under regional poles constrains described by linear matrix inequality （LMI）. These LMIs are easy to solve through the Matlab LMI-toolbox. Simulations indicate that the controller has excellent dynamic, static and disturbance rejection performance, and the control system is robust and has perfect H2 performance to the bounded external torque disturbance.

LQ Speed Control of Pump Controlled Motor System

A linear quadric (LQ) optimal speed control algorithm is proposed for the speed control of a pump controlled motor hydraulic system. The control theme consists of optimal state feedback and disturbing compensation based on observation. The optimal state feedback bases on LQ cost function. The disturbing compensation is realized through reconstructing the state of load torque. A series of simulation are performed, and the results show that the control performance is satisfactory and can be maintained under changes of load torque.

STUDY ON POWER SPARE COEFFICIENT OF ELECTRICAL MOTOR IN LARGE PUMP STATION BASED ON RELIABILITY

Characters of head of low head pump station and the pump shaft power areanalyzed. Influence of each single factor on pump shaft power is expressed as change of specificshaft power. (non-dimensional) and the probability density function is determined. Influences ofmultiple factors on pump shaft power are analyzed. Method of calculating none over-loadedprobability of motor by integration by successive reductions is put forward and then relationbetween power spare coefficient and none over-loaded reliability of electric motor is established.Influences of all factors on pump shaft power being considered completely; power spare coefficientsof motor are calculated in three kinds of heads (changing and unchanging), two kinds of dirty-outconditions. Electrical motor power spare coefficients should be chosen as 1.20 approx 1.44, 1.11approx 1.19, 1.09 approx.14 respectively when pump heads are 4, 7, 9.5 m. The results mean much toreasonable choose of electrical motors in large pump stations, increasing reliability of pump unitsand saving equipment investment.

Dynamic Modelling of Submersible Pump Based Solar Water-Pumping System with Three-Phase Induction Motor Using MATLAB

The main purpose of this paper is to design and model a water-pumping system using a submersible multi-stage centrifugal pump driven by a three-phase induction motor. The system is intended for pumping water to the surface from a deep well using three power supply systems: a general network, a photo-voltaic (PV) system, and a PV system with a battery bank. These systems are used to compare two three-phase induction motors—namely, a motor with a drive and another one without a drive. The systems dynamic models are simulated in MATLAB/Simulink and the results compared with the manufacturer’s data for validation purposes. The simulation results generally show system dynamics and expected performance over a range of operation.

The Design of a Mobile Phone-Based Remote-Control Application to Submersible Motor for Effective Water Supply

In the last few decades, several monitoring systems integrated with water level detection have been the major research focus. Production boost and its sustainability depend mainly on sustainable water supply, measuring water level, and avoiding waste of water is an essential task for all stakeholders. Therefore, the aim of this paper is to design and implement a mobile phone-based remote control. This will be applied to control the operation of a submersible motor in a water tank. The water level in the tank is detected and the device remotely turns the motor pump on/off. The design process is accomplished by developing an android application that works on GSM technology to manage the filling of water tank. An AT89C51 microcontroller is used for the desired programming. At the transmitting end, sensor is used for level detection and GSM module is used to send the information to user. According to this information, user controls the on/off operation of the pump. A SIM card is required for its operation and it works on attention (AT) commands. After the design and implementation of the device, the test results showed that all features of the device worked properly, and the device functions exactly as expected. More significantly, the paper has shown that ultrasonic sensors can be used to determine the level of water in a water tank and a GSM module can be used to control a submersible pump. The design and implementation of this device can help to reduce waste of time and power. Ultimately, it avoids water wastage thereby ensuring availability, conservation, and sustainability of water supply.

Submersible direct-drive progressing cavity pump rodless lifting technology

Submersible electrical motor direct-drive progressing cavity pump (PCP) rodless lifting was studied to solve the traditional rod-drive pump problems, such as rod-tubing wearing, low efficiency and short running time. The theoretical researches and laboratory experiments of key tools such as submersible motor and the construction technology of lifting system were introduced. The field application and economic benefit were analyzed and compared with the traditional rod pumping unit. A new low speed and large torque permanent magnet synchronous motor was developed. This motor was used to drive PCP without gear reducer, which improved the reliability and feasibility. It can run at the speed from 50 to 500 r/min with stepless speed regulation, and it can perform high efficiency and large torque. Besides, other key supporting tools, such as motor protector and flex shaft, were developed. The submersible electrical motor direct- drive PCP technology can be used in a 139.7 mm (5.5 in) casing well, with daily output ranging from 5 to 50 m3. Until now, the technology has been deployed more than 100 wells. The field application results show that it eliminates the rod-tubing wearing and saves electric energy by more than 30% compared with the traditional rod pumping unit. And it also makes the oil produced in a safe and environmental friendly way.

PV-Grid Tie System Energizing Water Pump

This paper presents the behaviours of three-phase induction motor driving centrifugal pump under various solar irradiation levels, where the motor speed and torque depend on the source voltage and frequency, while the water-flow rate depends on the motor speed, density, and static head according to affinity flow. Matlab/Simulink model is proposed for studying the behaviours of these machines with respect to water flow capacity, motor current, electro-magnetic torque, and motor efficiency. The proposed photovoltaic with maximum power point tracking model based on observation and perturbation (O&P) maximum power tracking model is applied. The output voltage is regulated throughout Buck-Boost converter with purpose maintaining the output voltage at predetermined values. Since Induction motors are widely used in pump systems, the electromagnetic torque, water-flow rate are studied for various source frequencies. Comparison analysis is conducted for both motors with respect to water flow-rate, heads elevation, and motor current. In addition to that, the proposed system presents Photovoltaic-Grid (PV-Grid) Integrated model, where the power shortage required for normally operation of the pump is drawn from the electrical grid.

Variable Speed Photovoltaic Water Pumping Using Affinity Laws

Photovoltaic (PV) power is most commonly used for water pumping applications. The DC output voltage of PV arrays is connected to a DC-DC converter using a maximum power point tracking (MPPT) controller to maximize their produced energy. Then, that converter is linked to a voltage source inverter (VSI) that converts DC power to AC power. Vector control is used to control the VSI fed three phase induction motor driving the water pump. The Affinity laws are used to change the pump characteristics by changing the pump speed, and consequently, the pump flow rate, head, and power will be varied. In this paper, the Affinity laws are adapted to achieve the pump hydraulic requirements while the power delivered to the pump motor remains unchanged by constructing new pump curves. A Matlab/Simulink model of the PV pumping system is observed over a wide range of weather and loading conditions.

基于混合模型的特种车辆转向泵马达性能评估

为了实现转向泵马达运行性能的实时评估,首先构建了转向泵马达物理模型,该模型考虑了转向泵马达运行机理,通过求解泵马达外特性方程、液压回路平衡方程、内部流量计算方程等,实现内部不可测参数的初步评估与计算,进而获得各类参数对转向泵马达性能的影响机制.同时采用LSTM深度学习方法构建了转向泵马达数据驱动模型,学习并预测不同工况下转向泵马达容积效率的变化规律,并将其输入至物理模型形成转向泵马达性能评估混合模型,提高不同工况条件下转向泵马达性能评估的准确性及适用性.实例分析表明,该混合模型可实现复杂工况下转向泵马达高低压侧压力、流量、转速及转矩等参数的计算与评估,模型误差低于10%.

A new diagnostic method for identifying working conditions of submersible reciprocating pumping systems

The submersible pumping unit is a new type of pumping system for lifting formation fluids from onshore oil wells, and the identification of its working condition has an important influence on oil production. In this paper we proposed a diagnostic method for identifying the working condition of the submersible pumping system. Based on analyzing the working principle of the pumping unit and the pump structure, different characteristics in loading and unloading processes of the submersible linear motor were obtained at different working conditions. The characteristic quantities were extracted from operation data of the submersible linear motor. A diagnostic model based on the support vector machine （SVM） method was proposed for identifying the working condition of the submersible pumping unit, where the inputs of the SVM classifier were the characteristic quantities. The performance and the misjudgment rate of this method were analyzed and validated by the data acquired from an experimental simulation platform. The model proposed had an excellent performance in failure diagnosis of the submersible pumping system. The SVM classifier had higher diagnostic accuracy than the learning vector quantization （LVQ） classifier.

基于多点电压电流信息融合的泵房设备故障诊断方法

为了实现自来水厂泵房及其二次加压泵房中配电设备与水泵故障的快速在线诊断与报警,保障泵房设备的安全运行,提出一种基于多点电压与电流信息融合技术的泵房设备故障在线诊断方法.基于泵房设备配电系统与设备构成,从理论上系统地分析了泵房配电设备与水泵常见故障所具有的电压与电流特征及其相互影响机理,使用配电线路中多个关键节点的实时电压、电流测量值进行融合处理,提取泵房配电主回路供电电压超限、配电线路中空气开关或接触器触头开路、水泵电机绕组开路、水泵电机绕组不平衡与匝间短路、水泵堵转、电机与水泵连接机构断开6类故障的故障特征,实现这些故障的在线诊断.阐述了故障诊断方法的执行条件、实现原理及具体实现步骤.使用MATLAB/Simulink搭建仿真模型进行实验验证,仿真结果表明,本文方法能有效地诊断泵房设备故障,克服了现有人工排查耗时耗力与离线分析不及时的不足,为自来水厂及其二次加压泵房配电设备与水泵的安全运行提供有效保障.

基于TRIZ理论的一种提升罗茨真空泵基础压力的设计方法

以TRIZ理论为研究工具,采用因果分析方法得到了影响罗茨真空泵基础压力的根本原因和薄弱点,通过技术矛盾和技术系统进化法则解决方案模型的启示,进一步改进了罗茨真空泵的密封结构和转子型线,然后基于改进方案,对ZJP70型罗茨真空泵进行了优化。测试结果表明:在同等条件下,优化后的新型罗茨真空泵基础压力提升明显,同时最大零流量压缩比、整机漏率和噪声等核心指标也得到了显著改善。

基于FPCB绕组的导管泵用电动机设计及损耗分析

基于无槽无刷直流电动机具有体积小、功率密度高、无齿槽转矩的特点,采用柔性印刷电路板(FPCB)技术设计了一种导管泵用无槽无刷微型直流电动机,提出了基于3D多物理场耦合模型分析方法,对导管泵用无槽无刷微型直流电动机进行了损耗分析和优化设计.结果表明:导管泵用无槽无刷微型直流电动机的铜损占整个电动机损耗的88%左右,是导致电动机发热的主要原因;在温度场仿真中,温度变化会改变电动机损耗,影响电动机输出转矩;在流场仿真模型中,电动机温度会使人体血液温度升高,影响血液相容性;流动的血液会带走部分热量,降低电动机温度;绕组优化后的导管泵用电动机输出转矩得到提高,损耗得以降低.

Power Stabilization System with Counter-Rotating Type Pump-Turbine Unit for Renewable Energy

Traditional type pumped storage system contributes to adjust the electric power unbalance between day and night, in general. The pump-turbine unit is prepared for the power stabilization system, in this serial research, to provide the constant power with good quality for the grid system, even at the suddenly fluctuating/turbulent output from renewable energies. In the unit, the angular momentum changes through the front impeller/runner must be the same as that through the rear impeller/runner, that is, the axial flow at the outlet should be the same to the axial flow at the inlet. Such flow conditions are advantageous to work at not only the pumping mode but also the turbine mode. This work discusses experimentally the performance of the unit, and verifies that this type unit is very effective to both operating modes.

真空泵用屏蔽电机无传感器残压重投控制策略

针对真空干泵机组故障、生产工艺需要等原因影响真空设备产线在线运行时间的问题,研究真空干泵用屏蔽式感应电机带速重投策略,寻求重投的有利时刻以保证带速重投的成功,对电机断电后的转速和定子失电残压特性展开研究。为此,根据屏蔽感应电机空间向量模型,建立基于电压电流混合磁链观测的无速度传感器估算模型、推导电机断电期间的转速估算方法以及定子失电残压解析式。通过重点研究定子残压和虚拟重投电压间幅值特性和相角特性,确定控制系统的首次重投点和其次重投点。以4 kW真空干泵用屏蔽感应电机机组为例,通过模型仿真和失电残压实验验证了该控制方法在泵类工程中有较好的适用性和准确性,重投阶段的转速稳定时间为0.5 s以内,重投阶段的冲击电流平均减小59.18%。

大型变速抽水蓄能发电电动机不同转速下三维端部电磁场和损耗研究

大型变速抽水蓄能发电电动机端部区域漏磁和构件损耗较高,为了研究不同转速时大型变速抽水蓄能发电电动机三维端部电磁场和端部构件损耗的变化规律,本文建立326 MW变速抽水蓄能发电电动机三维端部瞬态电磁场的数学模型,研究变速抽水蓄能电机在发电机工况下不同转速时定转子端部构件磁密的变化规律,确定变速抽水蓄能电机端部构件涡流密度的分布情况,探究变速抽水蓄能电机在发电机工况下不同转速时定子压圈、定子环板、转子护环以及转子齿压板等端部构件损耗的变化规律。采用相同的计算方法对小容量10 MW变速抽水蓄能发电电动机进行研究,通过试验测试和计算结果的对比验证了本文计算方法的可行性。

泵/马达困油现象充分缓解的等排量大模数方法

为了充分缓解外啮合齿轮泵/马达困油现象,在确保产品输出能力不变的等排量前提下,分析模数对困油腔内的负荷流量、泄漏流量和卸荷流量的影响,提出了一种等排量大模数的设计方法,并基于这3种流量的瞬时平衡和同齿形参数、不同模数下卸荷面积的演绎计算,计算出困油压力并由此判断出困油现象的缓解程度。结果表明,对于给定的齿轮副和工况条件,等排量下的齿宽系数反比例于模数的3次方,模数越大,困油现象越趋于缓解,且径向力越小,但齿宽系数越小;同齿形参数、不同模数下的卸荷面积等于模数的平方乘基准模数为1下的卸荷面积,从而为同齿形参数、不同模数下的卸荷面积计算,提供了极大方便;卸荷槽外通的进出口压力互为颠倒,导致泵较马达的困油现象更严重,但等排量小模数马达同样也会出现较为严重的困油现象。得出了选择最大化/较大的模数应为泵/马达的设计准则的重要结论。