Design and Implementation of Redundant Sensors in Active Magnetic Bearing

2017 ◽  
Author(s):  
Zhengang Shi ◽  
Jiaji Yang ◽  
Ni Mo ◽  
Xingnan Liu ◽  
Yan Zhou
Keyword(s):  
High Reliability ◽  
Short Circuit ◽  
Stability Control ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Displacement Sensor ◽  
Special Equipment ◽  
Design And Implementation ◽  
Displacement Sensors ◽  
Redundancy Design

With the advantages of frictionless, no need of lubrication, no pollution, low consuming and long life, active magnetic bearing (AMB) is applied in the primary helium circulator of the High Temperature Gas-Cooled Reactor-Pebble bed Module (HTR-PM), which is under construction in Shidao Bay Nuclear Power Plant. Active magnetic bearing is a typical mechatronic system with interconnection of mechanical and electronic components with the function of picking up signals, processing and producing. Displacement sensor is an important component to pick up signals for stability control, and also the most susceptible part to fail due to variation of air temperature and vibration of high rotation speed. However, rotating system can’t run normally if a single sensor fails in AMB without redundancy design. For security considerations, higher reliability is required in some special equipment, especially in primary helium circulator of HTR-PM. Design and implementation of redundant sensors is an effective method. This paper reviewed the present research of fault diagnosis and redundant control of displacement sensors, simulation of coil’s short-circuit and open-circuit fault was made with MATLAB/SIMULINK. Parameters were optimized for fault diagnostic circuit by Multisim. Based on the high reliability demand, redundancy design was applied both on structure and control system in AMB. Schematic drawing and PCB board were finished by Altium Design, and experiments were carried out. The result showed that if the coils of sensor failed, AMB system could still work normally by switching to the redundant sensors automatically.

Circularity Error Analysis of Axial Displacement Sensor Detecting Surface for Active Magnetic Bearings of 10MW High Temperature Gas-Cooled Reactor (HTR-10GT)

2013 ◽  
Author(s):  
Jingjing Zhao ◽  
Yan Zhou ◽  
Zhe Sun ◽  
Suyuan Yu
Keyword(s):  
High Temperature ◽  
Degrees Of Freedom ◽  
Magnetic Bearing ◽  
Axial Displacement ◽  
Working Environment ◽  
Active Magnetic Bearing ◽  
Displacement Sensor ◽  
Displacement Sensors ◽  
Circularity Error ◽  
High Temperature Gas

The 10MW high temperature gas-cooled test module reactor (HTR-10GT) with the core made of spherical fuel elements was designed and constructed by the Institute of Nuclear and New Energy Technology of Tsinghua University in China. In the HTR-10GT, turbo-compressor and generator rotors are connected by a flexible coupling and a decelerator. The rotors, restricted by actual instruments and working environment, must be supported without any contact and lubrication. Active magnetic bearing (AMB), is the best way to suspend and stabilize the position of rotors of HTR-10GT. In AMB system, the displacement sensors are designed for converting measured physical value into proportional electric signals and transferring it into the control and monitoring system. The characteristics and influence of circularity error of the axial displacement sensor detecting surface is analyzed according to AMB with five degrees of freedom. In order to reduce the circularity error of the magnetic bearing system, the sensor detecting surface requires high-precision machining.

scholarly journals INDUCTIVE LINEAR DISPLACEMENT SENSOR IN ACTIVE MAGNETIC BEARING

2019 ◽  
Vol 3 ◽  
pp. 151
Author(s):  
Sergei Loginov ◽  
Dmitriy Fedorov ◽  
Igor Savrayev ◽  
Igor Plokhov ◽  
Andrey Hitrov ◽  
...  
Keyword(s):  
Control System ◽  
High Speed ◽  
High Reliability ◽  
Magnetic Bearing ◽  
Linear Displacement ◽  
Magnetic Bearings ◽  
Active Magnetic Bearing ◽  
Displacement Sensor ◽  
Main Trend ◽  
Active Magnetic Bearings

Active magnetic bearings are increasingly used in various fields of industry. The absence of mechanical contact makes it possible to use them in ultra-high-speed electric drives. The main trend of active magnetic bearings development is the improvement of the control system. The main problem of the control system is the displacement sensor (most of them has low accuracy and large interference). The sensor must have the following properties: simple in realization, high linearity of the characteristic, high sensitivity and noise immunity, high reliability. At the present time there is no sensor that satisfies all these conditions. Most manufacturers use various kinds of filters to get an accurate position signal. This increases the response time of the control system. Thus, problem of designing and modeling the position sensor, considered in the article is topical.

scholarly journals Inductive Displacement Sensors with a Notch Filter for an Active Magnetic Bearing System

Sensors ◽  
2014 ◽  
Vol 14 (7) ◽  
pp. 12640-12657 ◽  
Author(s):  
Seng-Chi Chen ◽  
Dinh-Kha Le ◽  
Van-Sum Nguyen
Keyword(s):  
Notch Filter ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Displacement Sensors ◽  
Bearing System

Evaluation of Q-Values of a Rotor-Bearing System Using a Modal Open Loop Transfer Function

2009 ◽  
Author(s):  
Hiroyuki Fujiwara ◽  
Yasuo Fukushima ◽  
Naohiko Takahashi ◽  
Hiroto Oyama ◽  
Osami Matsushita
Keyword(s):  
Transfer Function ◽  
Damping Ratio ◽  
Magnetic Bearing ◽  
Open Loop ◽  
Active Magnetic Bearing ◽  
Q Value ◽  
Oil Whip ◽  
Displacement Sensors ◽  
Loop Transfer Function ◽  
Value Estimation

As indicated by ISO standard 10816, Q-value estimation is very important for rotating machinery commission and/or machine safety operation. Impulse tests and resonance curve measurements are commonly contributed to Q-value estimation. Instead of two methods, we are developing a new method using open-loop transfer function (Go) at real operational condition. In this paper, we present a theoretical background on how to measure the open loop transfer function. Our key technique is the measurement of the modal coordinates with a combination of several displacement sensors. Concerning the experimental measurement of Go, we use multiple sensors and only one active magnetic bearing (AMB) in a rotor system supported by oil-film/ball bearing. This Go is converted to damping ratio. In fact, a smaller damping ratio is recognized just before oil-whip instability by our open loop measurement. In addition, we set a dynamic damper which has been developed for suppression of oil whip instability, and an increasing damping ratio is also recognized by our method.

scholarly journals Research on Coil Impedance of Self-Inductive Displacement Sensor Considering Core Eddy Current

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6292
Author(s):  
Zongqiang Ren ◽  
Hongwei Li ◽  
Wentao Yu
Keyword(s):  
Electromagnetic Field ◽  
Theoretical Model ◽  
Eddy Current ◽  
Experimental Situation ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Displacement Sensor ◽  
Complex Permeability ◽  
Impedance Change ◽  
Finite Element Software

The inductive displacement sensor is widely used in active magnetic bearing (AMB) systems to detect rotor displacement in real time, and the performance of the sensor directly affects the performance of AMB. At present, most theoretical studies on the working principle of inductive displacement sensor are based on a traditional mathematical model, ignoring the influence of the core magnetic resistance and core eddy current, which will lead to a certain error between the theoretical analysis of the sensor output characteristics and the actual situation. In this regard, based on the theory of electromagnetic field and circuit, an improved theoretical model of the inductive sensor was established in this paper by introducing the complex permeability, by which the influence of core eddy current on magnetic field can be taken into account. In order to verify the improved model, an eight-pole radial self-inductive displacement sensor with an air gap of 1 mm was designed. Then the electromagnetic field of the designed sensor was simulated by a finite element software and the GW LCR-6100 measuring instrument was used to measure the changes of the inductance and resistance of the designed sensor core coils with the rotor displacement at 20–100 kHz. The results demonstrated that there is a good linear relationship between the impedance change of the sensor coils and the rotor displacement within the measurement range of −0.4 ~ +0.4 mm. At the same time, compared with the traditional model, the sensitivity of the improved theoretical model is closer to the results from FEM and experiment, and the accuracy of the sensitivity of the improved theoretical model can be approximately doubled, despite there are certain differences with the experimental situation. Therefore, the improved theoretical model considering complex permeability is of great significance for studying the influence of core eddy current on the coil impedance of sensor.

Magnetically Suspended Rotary Blood Pump (Keynote)

2005 ◽  
Author(s):  
Hooshang Heshmat ◽  
James F. Walton ◽  
Michael J. Tomaszewski ◽  
Said Jahanmir
Keyword(s):  
High Reliability ◽  
Medical Center ◽  
Magnetic Bearing ◽  
Operating Conditions ◽  
Active Magnetic Bearing ◽  
Blood Pump ◽  
Rotary Blood Pump ◽  
Centrifugal Blood Pump ◽  
Pump Rotor ◽  
Blood Flows

MiTiHeart™ LVAD is a rotary centrifugal blood pump with a hybrid passive/active magnetic bearing support system. It exhibits low power loss, low vibration, and high reliability under transient operating conditions. Unique features of the design include a simple and direct flow path for both main and washing blood flows, non-contact pump rotor, i.e., no rubbing surfaces, and relatively large clearances between the pump rotor and housing. The first prototype was constructed from medical grade polycarbonate. To reduce the possibility of thrombosis, the internally exposed surfaces were coated with a biocompatible polymer. Hemolysis test results showed a low normalized index of hemolysis of 0.01 mg/dL. An acute animal test was successfully completed at the Hershey Medical Center. During the test, the pump was implanted in a calf and operated in parallel with the heart. Following the acute test a chronic 200-hour implant study was completed. A second prototype was constructed using a titanium alloy for all blood contacting surfaces and incorporating a redundant hydrodynamic thrust bearing. This prototype was successfully evaluated in two chronic implant studies in a calf animal model for a total of 130 hours.

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