永磁伺服电机驱动的液压动力系统性能及测控技术研究

发布时间：2018-07-30 08:25

【摘要】：针对液压动力系统中定速定量泵液压源能耗高、效率低，定速变量泵系统结构复杂、抗污染能力差、调速范围窄，以及异步变频电机驱动液压系统惯性大、响应慢、低速性能差、电机功率因数低等缺点，本文提出了基于永磁同步伺服电机驱动定量泵的液压动力源结构形式，将永磁电机调速精度高、调速范围宽、动态特性好、功率因数高等优点与齿轮泵抗油液污染能力强、工作可靠性高、结构紧凑、价格低廉等优点相结合。在充分研究伺服电机电压、电流、转速、转矩，定量泵的流量、压力、排量、泄漏量，以及油液的温度、粘度、弹性模量等系统参数的基础上，，提出了定量泵输出流量、压力的软测量方法；针对不同负载类型实现了伺服驱动液压动力系统的流量控制、压力控制、恒功率控制；提出了不同工况下液压动力系统效率状态图示分析方法，为液压动力系统高效节能运行、负载匹配、负载自适应控制提供了新思路、新方法。本文完成的主要研究与创新工作：（1）根据永磁同步伺服电机的工作原理，以齿轮泵为例，利用解析法建立了伺服电机驱动定量泵液压动力系统数学模型和比例溢流阀加载模型；从系统层面对液压动力系统的运行参数、耦合机理、约束条件进行分析，为液压动力系统的控制模式、流量-压力间接测量、负载效率匹配特性研究奠定理论基础。（2）根据液压动力系统流量、压力、转速、转矩电流、泄漏系数、转动惯量等参数的耦合机理，建立了流量、压力的软测量模型，通过容易测量的转速、转矩电流等相关参数实现了流量、压力的间接测量，根据油液的粘温粘压特性对流量测量模型进行补偿，提高流量测量模型精度。实验和仿真表明：软测量模型具有足够的精度和动态响应速度，保证流量控制精确性、快速性和稳定性指标。（3）在分析了流量开环控制、流量闭环PID控制、前馈补偿PID控制和模糊参数PID控制的基础上，提出了流量的模型与条件PID补偿控制，将模型开环控制响应及时、容易稳定的特点与PID控制能够消除系统稳态误差的特点相结合，并且可通过PID控制中条件阈值的设定有效减小系统超调量和调整时间，实现了流量控制的快速性、准确性和稳定性要求。（4）根据工程中广泛使用的恒压变量泵技术性能指标，提出了伺服驱动液压源的压力负反馈控制和直接转矩压力开环控制，实验表明：压力负反馈控制能够稳定系统压力，消除系统误差；直接转矩压力开环控制响应速度快，稳定性好；而带有粘滞阻尼补偿的直接转矩压力开环控制既保持了原有转矩压力控制的快速性、准确性的同时，还具有足够的精度，能够满足负载对恒压变流量的需求。（5）对恒功率变量泵控制特性进行分析，建立了永磁电机驱动定量泵恒功率控制模型，提出了电机的弱磁升速控制，仿真与实验均表明：液压源恒功率、电机弱磁升速控制时能够充分利用电机的功率，并且能够自动适应负载流量、压力恒功率变化需求，实现液压动力源输出高压小流量和低压大流量控制。（6）对感应异步电机和永磁同步电机驱动液压动力源的能耗、调速特性、功率匹配、响应特性等主要技术性能进行了对比分析；通过工况等效变换研究了负载效率匹配特性，建立了基于RGB的效率二维彩色表示法和基于叠加法的效率二维灰度表示法，为负载匹配选型、效率工况区间划分提供了直观的图示化新方法。
[Abstract]:In view of the disadvantages of high energy consumption, low efficiency, low efficiency, low efficiency, low pollution resistance, narrow speed regulating range, high inertia of the hydraulic system driven by asynchronous frequency conversion motor, slow response, poor low speed performance and low power factor of the motor, this paper proposes a permanent magnet synchronous servo motor drive in this paper. The hydraulic power source structure of the dynamic quantitative pump has the advantages of high speed regulating precision, wide speed range, good dynamic characteristic, high power factor, high power factor, high reliability of gear pump, high working reliability, compact structure, low price and so on. It is fully studied the voltage, current, speed, torque and quantitative pump of servo motor. On the basis of the system parameters such as flow, pressure, displacement, leakage, temperature, viscosity and elastic modulus of the oil, a soft measurement method for the output flow and pressure of the pump is put forward, and the flow control, pressure control and constant power control of the servo driven hydraulic power system are realized for different load types, and the hydraulic pressure is put forward in different working conditions. The graphical analysis method of efficiency state of power system provides new ideas and new methods for high efficiency and energy saving operation of hydraulic power system, load matching and load adaptive control. The main research and innovation work completed in this paper is:
(1) according to the working principle of the permanent magnet synchronous servo motor and taking the gear pump as an example, the mathematical model of the hydraulic power system of the servo motor driven quantitative pump and the proportional overflow valve loading model are established by analytic method, and the operation parameters, coupling mechanism and constraint conditions of the hydraulic power system are analyzed from the system layer, and the control of the hydraulic power system is made. It lays a theoretical foundation for the research of indirect measurement of flow pressure and load efficiency matching characteristics.
(2) according to the coupling mechanism of the parameters of the hydraulic power system, such as flow, pressure, speed, torque current, leakage coefficient, and moment of inertia, the soft measurement model of flow and pressure is established. The flow and pressure are measured by the parameters of speed, torque current and other related parameters easily measured, and the flow measurement model is based on the viscosity and pressure characteristics of the oil. The accuracy of the flow measurement model is improved. The experiment and simulation show that the soft sensing model has enough precision and dynamic response speed to ensure the accuracy, speediness and stability of the flow control.
(3) on the basis of analyzing the flow open loop control, the flow closed loop PID control, the feedforward compensation PID control and the fuzzy parameter PID control, the flow model and the conditional PID compensation control are proposed. The characteristics of the model open loop control response in time and the stability are combined with the characteristics of the PID control that can eliminate the steady-state error of the system, and can be passed through PID. The setting of the conditional threshold in the control effectively reduces the overshoot and adjustment time of the system, and realizes the rapidity, accuracy and stability requirements of the flow control.
(4) according to the technical performance index of constant pressure variable pump widely used in the project, the pressure negative feedback control and direct torque pressure open loop control of the servo driven hydraulic source are put forward. The experiment shows that the pressure negative feedback control can stabilize the system pressure and eliminate the system error; the direct torque pressure open loop control has fast response speed and good stability. The direct torque pressure open loop control with viscous damping compensation not only keeps the speed of the original torque pressure control, but also has enough accuracy to meet the demand of the load to constant pressure variable flow.
(5) the constant power variable pump control characteristic is analyzed, the permanent magnet motor driving quantitative pump constant power control model is established, and the weak magnetic lifting speed control of the motor is put forward. The simulation and experiment show that the power of the hydraulic source is constant and the motor weak magnetic lifting speed control can fully utilize the power of the motor, and it can automatically adapt to the load flow and pressure constant. Power change needs to control the output of hydraulic power source with high pressure and low flow rate and large flow rate.
(6) the energy consumption, speed regulation, power matching and response characteristics of induction induction motor He Yongci synchronous motor are compared and analyzed. The matching characteristics of load efficiency are studied by the equivalent transformation of working conditions, and two dimensional color representation method based on RGB and two dimensional efficiency based on superposition method are established. Grayscale representation provides an intuitive graphical method for load matching selection and efficiency division.
【学位授予单位】：西安建筑科技大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TH137;TM383.4

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