SHI Yu-ping1, GU Li-chen1,2, ZHAO Song1, LIU Chang-chang1
（1. School of Construction Machinery, Chang’an University, Xi’an 710064, China；2. School of Mechanical-Electronic Engineering, Xi’an University of Architecture and Technology, Xi’an 710054, China）
Abstract： In order to online monitor the running state of variable voltage and variable frequency(VVVF) hydraulic system, this paper presents a graphic monitoring method that fuses the information of variable frequency electric parameters. This paper first analyzes how the voltage and current of the motor stator change with the operation conditions of VVVF hydraulic system. As a result, we draw the relationship between the electric parameters (voltage and current) and power frequency. Then, the signals of the voltage and current are fused as dynamic figures based on the idea of Lissajous figures, and the values of the electric parameters are related to the features of the dynamic figures. Rigorous theoretical analysis establishes the function between the electric power of the variable frequency motor (VFM) and the features of the plotted dynamic figures including area of diagram, area of bounding rectangle, tilt angle, etc. Finally, the effectiveness of the proposed method is verified by two cases, in which the speed of VFM and the load of VVVF hydraulic system are changed. The results show that the increase of the speed of VFM enhances its three-phase electric power, but reduces the tilt angle of the plotted dynamic figures. In addition, as the load of VVVF hydraulic system is increased, the three-phase electric power of VFM and the tilt angle of the plotted dynamic figures are both increased. This paper provides a new way to online monitor the running state of VVVF hydraulic system.
Key words： variable frequency motor (VFM); hydraulic system; condition monitoring; Lissajous figures; electric power; information fusion
CLD number： TP271+.31 Document code： A
Article ID： 1674-8042（2018）04-0307-09
doi： 10.3969/j.issn.1674-8042.2018.04.001
References
［1］ Cui N X, Zhang C H, Du C S. Advances in efficiency optimization control of inverter-fed induction motor drives. Transactions of China Electrotechnical Society, 2004, 19(5)： 36-42.
［2］ Kirschen D S, Novotny D W, Lipo T A. On-line efficiency optimization of a variable frequency induction motor drive. IEEE Transactions on Industry Applications, 1985, IA-21(3)： 610-616.
［3］ Kioskeridis I, Margaris N. Loss minimization in induction motor adjustable-speed drives. IEEE Transactions on Industrial Electronics, 1994, 43(1)： 226-231.
［4］ Zhang J M, Yang H Y, Chen G. The application of frequency control technology in speed control of hydraulic elevators. Chinese Hydraulics and Pneumatics, 1997, (5)： 9-10.
［5］ Zeng Z R. The application of frequency control technology in bridge incremental launching hydraulic system. Chinese Hydraulics and Pneumatics, 2013, (10)： 62-65.
［6］ Bao E B. The application of frequency control technology in hydraulic pipe jacking machine. Fluid Power Transmission and Control, 2012, (6)： 41-42.
［7］ Jiang W, Gao Q H, Zhang Z Y. A survey of fault diagnosis technology for hydraulic system. Hydraulics Pneumatics and Seals, 2010, 30(11)： 8-12.
［8］ Hou X G, Wu Z G, Xia L. A method for detecting rotor faults in asynchronous motors based on the Park’s vector modulus. In： Proceedings of the CSEE, 2003, 23(9)： 137-140.
［9］ Ukil A, Chen S, Andenna A. Detection of stator short circuit faults in three-phase induction motors using motor current zero crossing instants. Electric Power Systems Research, 2011, 81(4)： 1036-1044.
［10］ Legowski S F, Sadrul Ula A H M, Trzynadlowski A M. Instantaneous stator power as a medium for the signature analysis of induction motors. IEEE Transactions on Energy Conversion, 1996, 32(4)： 904-909.
［11］ Luo P P. Running state monitoring for hydraulic system base on the electrical Lissajous graph. Xi’an： Xi'an University of Architecture and Technology, 2015： 8-15.
［12］ Drif M, Cardoso A J M. Stator fault diagnostics in squirrel cage three-phase induction motor drives using the instantaneous active and reactive power signature analyses. IEEE Transactions on Industrial Informatics, 2014, 10(2)： 1348-1360.
［13］ Kirschen D S, Novotny D W, Suwanwisoot W. Minimizing induction motor losses by excitation control in variable frequency drives. IEEE Transactions on Industry Application, 1984, IA-20(5)： 1244-1250.
［14］ Gu L C, Liu P J. A monitoring method for power condition of AC motors via graphic recognition. In： Proceedings of the CSEE, 2012, 32 (9)： 100-108.
［15］ Yang D Y. The principle of control and frequency control of the motor. Beijing： China Machine Press, 2012： 170-193.
［16］ Peng L J, Gu L C, Liu P J. Design of hydraulic equipment electricity parameters data acquisition system based on DSP. Electrical Measurement and Instrumentation, 2010, 47(3)： 59-67.
变频调速液压系统电功率图形化监测方法
石玉萍1， 谷立臣1,2， 赵 松1， 刘畅畅1
（1. 长安大学 机械工程学院， 陕西 西安 710064； 2. 西安建筑科技大学 机电工程学院， 陕西 西安 710054）
摘 要： 为了在线监测变转速泵控液压系统的运行状态， 识别其负载工况， 提出了基于变频电参量信息融合的图示化监测方法。 分析了变转速泵控液压系统动力源—变频电机的定子电压、 电流随工况的变化规律， 揭示了电压、 电流幅值随频率变化的特点； 基于李萨如方法将变频电机的电压电流信号融合为李萨如动态图形， 包含了电机定子的三相电压、 电流中的幅值、 频率和相位差信息， 并理论推导、 分析了李萨如图形面积、 外接矩形面积、 摆动角度等特征量与变频电机功率之间的函数关系； 通过变转速、 变负载实验验证了提出方法的可行性与有效性。 实验与理论分析结果一致表明， 当转速升高时， 三相功率均随之增大， 而李萨如图倾角随之减小； 当负载增加时， 三项功率随之增大， 李萨如图倾角也随之增大， 从而为变转速泵控液压系统运行状态的在测监测提供了新方法。
关键词： 变频电机； 液压系统； 状态监测； 李萨如图形； 电功率； 信息融合
引用格式： SHI Yu-ping, GU Li-chen, ZHAO Song, et al. A graphic monitoring method for electric power of VVVF hydraulic system. Journal of Measurement Science and Instrumentation, 2018, 9(4)： 307-315. ［doi： 10.3969／j.issn.1674-8042.2018.04.001］
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