scholarly journals Stall Inception and the Prospects for Active Control in Four High-Speed Compressors

1999 ◽  
Vol 121 (1) ◽  
pp. 18-27 ◽  
Author(s):  
I. J. Day ◽  
T. Breuer ◽  
J. Escuret ◽  
M. Cherrett ◽  
A. Wilson
Keyword(s):  
Control System ◽  
Active Control ◽  
High Speed ◽  
Collaborative Project ◽  
Stall Inception ◽  
Speed Range ◽  
Full Speed ◽  
Stall Warning ◽  
Stall Control ◽  
Engine Type

As part of a European collaborative project, four high-speed compressors were tested to investigate the generic features of stall inception in aero-engine type compressors. Tests were run over the full speed range to identify the design and operating parameters that influence the stalling process. A study of data analysis techniques was also conducted in the hope of establishing early warning of stall. The work presented here is intended to relate the physical happenings in the compressor to the signals that would be received by an active stall control system. The measurements show a surprising range of stall-related disturbances and suggest that spike-type stall inception is a feature of low-speed operation while modal activity is clearest in the midspeed range. High-frequency disturbances were detected at both ends of the speed range and nonrotating stall, a new phenomenon, was detected in three out of the four compressors. The variety of the stalling patterns, and the ineffectiveness of the stall warning procedures, suggests that the ultimate goal of a flightworthy active control system remains some way off.

scholarly journals Stall Inception and the Prospects for Active Control in Four High Speed Compressors

1997 ◽  
Author(s):  
I. J. Day ◽  
T. Breuer ◽  
J. Escuret ◽  
M. Cherrett ◽  
A. Wilson
Keyword(s):  
Control System ◽  
Active Control ◽  
High Speed ◽  
Rotating Stall ◽  
Collaborative Project ◽  
Stall Inception ◽  
Speed Range ◽  
Full Speed ◽  
Stall Warning ◽  
Stall Control

As part of a European collaborative project, four high speed compressors were tested to investigate the generic features of stall inception in aero-engine type compressors. Tests were run over the full speed range to identify the design and operating parameters which influence the stalling process. A study of data analysis techniques was also conducted in the hope of establishing early warning of stall. The work presented here is intended to relate the physical happenings in the compressor to the signals that would be received by an active stall control system. The measurements show a surprising range of stall related disturbances and suggest that spike-type stall inception is a feature of low speed operation while modal activity is clearest in the mid speed range. High frequency disturbances were detected at both ends of the speed range and non-rotating stall, a new phenomenon, was detected in three out of the four compressors. The variety of the stalling patterns, and the ineffectiveness of the stall warning procedures, suggests that the ultimate goal of a flightworthy active control system remains some way off.

scholarly journals Simultaneous Load Disturbance Estimation and Speed Control for Permanent Magnet Synchronous Motors in Full Speed Range

2020 ◽  
Vol 10 (24) ◽  
pp. 9006
Author(s):  
Yingming Tian ◽  
Yi Chai ◽  
Li Feng
Keyword(s):  
Permanent Magnet ◽  
High Speed ◽  
High Efficiency ◽  
Weight Ratio ◽  
Permanent Magnet Synchronous Motors ◽  
Position Information ◽  
Synchronous Motors ◽  
Speed Range ◽  
Combined Control ◽  
Full Speed

Permanent magnet synchronous motors (PMSM), which are with the advantages of high torque-to-weight ratio and high efficiency, are widely applied in modern industrial systems. However, existing approaches may fail to accurately track the speed trajectory because of the load disturbances. This paper proposes an equivalent and combined control strategy to mitigate the slow time-varying load disturbances and decrease the overshoot for PMSM in full speed range. First, a state observer is proposed to reconstruct the current variables and speed state in the d-q axis. Hence, one can get the speed and position information without the sensors. Then, the disturbance and the load are estimated by the estimating law. Thus, it can reduce the effect of load and disturbances. Further, the PD control is introduced to weaken the overshoot. As a result, the speed trajectory can be more effectively hold both in high speed and low speed. Finally, numerical examples are presented to demonstrate the validity and effectiveness of the proposed estimation scheme and its robustness under different conditions.

A Control System for Chatter Avoidance by Ramping the Spindle Speed

1998 ◽  
Vol 120 (4) ◽  
pp. 674-683 ◽  
Author(s):  
E. Soliman ◽  
F. Ismail
Keyword(s):  
Control System ◽  
High Speed ◽  
Spindle Speed ◽  
Cutting Process ◽  
Statistical Indicator ◽  
Speed Range ◽  
Force Signal ◽  
On Line ◽  
Full Immersion ◽  
R Value

This paper presents a new control system for chatter avoidance in milling. The control system monitors the cutting process using a statistical indicator named the R-value which is computed from the cutting force signal. When chatter is detected, the control system ramps the spindle speed in search of a speed at which chatter ceases. The system does not involve time consuming computations and therefore is suitable for on-line implementation. Also, it does not interrupt the cutting process by halting the feedrate or the spindle speed. Simulations showed that the control system has a significant chatter avoidance potential in the high speed range, and also for partial and full immersion cuts. The system was implemented successfully to avoid chatter in slotting and half immersion down milling.

The Dynamic Analysis of an Energy Storage Flywheel System With Hybrid Bearing Support

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Hongchang Wang ◽  
Shuyun Jiang ◽  
Zupei Shen
Keyword(s):  
Control System ◽  
Energy Storage ◽  
Active Control ◽  
High Speed ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Squeeze Film ◽  
Transmitted Force ◽  
Hybrid Bearing ◽  
Active Control System

Active magnetic bearings and superconducting magnetic bearings were used on a high-speed flywheel energy storage system; however, their wide industrial acceptance is still a challenging task because of the complexity in designing the elaborate active control system and the difficulty in satisfying the cryogenic condition. A hybrid bearing consisting of a permanent magnetic bearing and a pivot jewel bearing is used as the support for the rotor of the energy storage flywheel system. It is simple and has a long working life without requiring maintenance or an active control system. The two squeeze film dampers are employed in the flywheel system to suppress the lateral vibration, to enhance the rotor leaning stability, and to reduce the transmitted forces. The dynamic equation of the flywheel with four degrees of complex freedom is built by means of the Lagrange equation. In order to improve accuracy, the finite element method is utilized to solve the Reynolds equation for the dynamic characteristics of the squeeze film damper. When the calculated unbalance responses are compared with the test responses, they indicate that the dynamics model is correct. Finally, the effect of the squeeze film gap on the transmitted force is analyzed, and the appropriate gap should be selected to cut the energy loss and to control vibration of the flywheel system.

scholarly journals Commissioning of a High Speed Composite Rotor With Hydrostatic Dampers and Ceramic Rolling Element Bearings

1993 ◽  
Author(s):  
Ross N. Headifen ◽  
Robert L. Fuller ◽  
Jon R. Kitzmiller
Keyword(s):  
High Speed ◽  
System Analysis ◽  
Rolling Element Bearings ◽  
Lumped Mass ◽  
One Dimensional ◽  
System A ◽  
Rolling Element ◽  
Speed Range ◽  
Full Speed ◽  
Stiffness And Damping

Abstract A high speed (25,000 rpm) routing machine with a 300 lb rotor was designed and manufactured. To accommodate the high shaft speed, 2.6 million DN, rolling element bearings were used with ceramic balls and inner races. In order to control the magnitude of the vibration, damping was incorporated into the system using nonrotating hydrostatic dampers. The journal for the dampers was a cylindrical cartridge that had the rolling element bearings clamped inside of it. Extensive analysis was performed on this system. A computer program was written that could model the orbit path of the lumped mass shaft in the damper over the full speed range. A second program was also written that calculated the damper nonlinear stiffness and damping coefficients, and incorporated them in with a one-dimensional beam, finite element rotordynamics model of the system. Analysis results are presented along with experimental run data from the machine. Balancing problems encountered during commissioning have limited the results to 16,500 rpm to date. The last of which is currently being remedied.

Hardware Design for Active Vibration Isolation Controller

2011 ◽  
Vol 211-212 ◽  
pp. 1061-1065
Author(s):  
Qiang Hong Zeng ◽  
Shi Jian Zhu ◽  
Jing Jun Lou ◽  
Shui Qing Xie
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Active Control ◽  
High Speed ◽  
Vibration Isolation ◽  
Active Vibration Control ◽  
Signal Acquisition ◽  
Acceleration Sensor ◽  
Series Acceleration ◽  
Active Vibration

The active vibration control system are described in this paper, and the controller was designed for the active control system, the controller is based on ARM Cortex M3 microcontroller core, ICP series acceleration sensor is use for signal acquisition module, the A / D converter module was designed based on ADS1158 chip, the D/ A converter module was designed based on DAC8564 chip. The controller has the characteristics of high speed and versatility.

Reduction of Hull Whipping in Slamming by Active Control System

1994 ◽  
Vol 38 (02) ◽  
pp. 115-122
Author(s):  
Wen-Jeng Hsueh ◽  
Ya-Jung Lee
Keyword(s):  
Control System ◽  
Active Control ◽  
High Speed ◽  
Active Vibration Control ◽  
Mathematical Formulation ◽  
Active System ◽  
Hull Girder ◽  
Hydraulic Servo ◽  
Active Vibration ◽  
Active Control System

The reduction of hull girder whipping in slamming by an active control system is investigated. Under the consideration of hull flexibility, a mathematical formulation is developed for the whipping of a hull, subject to slamming, and including an active vibration control system consisting of a tuned mass and hydraulic servo system. Using the optimal theory, the control law of the active system is determined. In addition, a closed-loop estimator is introduced to estimate the distribution of hull motion, which is required to compute the actuator output of the active system. Finally, a numerical example of an application to a 205-ton high-speed craft is described. The results show that the whipping will be reduced significantly. The whipping acceleration and induced stress in particular are reduced more than 95% within 2 sec by this scheme.

Stall Inception in a High-Speed Centrifugal Compressor

2001 ◽  
Author(s):  
Jeong-Seek Kang ◽  
Shin-Hyoung Kang
Keyword(s):  
Centrifugal Compressor ◽  
High Speed ◽  
Good Method ◽  
Fast Response ◽  
Stall Inception ◽  
Pressure Transducers ◽  
Stall Warning ◽  
Response Pressure ◽  
Set Up ◽  
Warning Time

Stall inception in a high-speed centrifugal compressor has been examined. The main objective was to find stall precursor and to develop a reliable stall warning method. Eight equally spaced fast-response pressure transducers in the inducer detected the spatial structure of small amplitude perturbations, via spatial Fourier transform, as stall is approached. Near the stall inception point, the phase of spatial Fourier coefficients increased linearly with the speed of impeller rotation for several impeller revolutions at all test speeds, and the spectrum at impeller frequency increased as stall is approached. This is the clear evidence that the impeller frequency participates in the stalling process. For stall warning, a method which uses the spectrum at impeller frequency is suggested. The use of spectrum at impeller frequency as a stall warning method showed a warning time of about two hundreds impeller revolutions. This method uses only one sensor that it has made the stall warning method more useful. And the well-known traveling wave energy method proved to be a good method for stall warning also in a high-speed centrifugal compressor. The warning time was about one hundred impeller revolutions at lower speeds, and about one thousand impeller revolutions at higher speeds. The stall warning methods used here were found to be robust and reliable. Therefore, it seems to be promising to set up a reliable stall avoidance control based on this analysis.

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