New Signal Conditioning Circuit for MR Angle Transducers With Full-Circle Range
22 Jan 2013-IEEE Transactions on Instrumentation and Measurement (IEEE)-Vol. 62, Iss: 5, pp 1308-1317
TL;DR: An efficient signal conditioning (SC) scheme that helps to obtain a linear output from a magnetoresistive (MR) angle sensor for 0–360 $^{\circ}$
Abstract: An efficient signal conditioning (SC) scheme that helps to obtain a linear output from a magnetoresistive (MR) angle sensor for 0 $^{\circ}$ –360 $^{\circ}$ range is presented in this paper. Most of the existing MR angle sensors have a sine/cosine relationship between the output and sensing angle, but a linear characteristic will be very useful. The new SC circuit of the proposed transducer accepts and processes output signals from an MR sensor that is sine/cosine in nature and gives an output directly proportional to the sensing angle. The sensitivity of the transducer output to variations in different circuit and mechanical parameters has been analyzed in detail, and their effect has been quantified. The functionality of the SC has been studied using SPICE simulations. A prototype of the proposed SC circuit has been built and tested using emulated sensor output signals. The output of the prototype circuit was linear from 0 $^{\circ}$ to 360 $^{\circ}$ , and worst case error was less than 0.08%. An angle sensor unit has been built using an MR sensor IC, interfaced to the SC circuit and tested. As expected, the output was found to be linear for a full-circle range.
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06 May 2013
TL;DR: This paper is focused on new methods of noncontact sensing vibrations and deflections of rotating machine parts, especially blades of steam turbines, developed in the Institute of Thermomechanics.
Abstract: The paper is focused on new methods of non-contact sensing vibrations and deflections of rotating machine parts, especially blades of steam turbines. Special attention is paid to the induction and magnetoresistive sensors developed in the Institute of Thermomechanics for non-contact measurements of characteristics of rotating blades inside steam turbines under operation. Different principles of non-contact sensors based on measuring deflections or velocity components are described and compared, including new types of magnetoresistive sensors. Hitherto unpublished principles of sensors intended for shrouded blades are described and discussed.
24 citations
Cites background from "New Signal Conditioning Circuit for..."
...formed by a permanent magnet or ferrite and a system of coils [11]....
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TL;DR: The proposed linearizing digitizer for TMR angle sensors (LDTA) converts sine and cosine natured analog outputs from the TMR sensor into a digital output that varies linearly over 360° range, done without using any analog-to-digital converter.
Abstract: This paper proposes an efficient linearizing direct digitizer for tunneling magnetoresistance (TMR)-based angular position sensor. The proposed linearizing digitizer for TMR angle sensors (LDTA) converts sine and cosine natured analog outputs from the TMR sensor into a digital output that varies linearly over 360° range. The digitization is done without using any analog-to-digital converter. The novel methodology of the LDTA ensures that its performance is least affected by the phase error of the quadratic oscillator used for sensor excitation. This principle also prohibits the adverse effects of the parasitic capacitances of the TMR sensor on angle measurement. Error sources influencing the LDTA performance are identified and analyzed. Detailed simulation and emulation studies of the LDTA were conducted to confirm its methodology. The worst case nonlinearity spotted during emulation studies remains within 0.08% for various probable values of phase error. A TMR-based angle sensor unit is designed and built. Interfacing the LDTA with the developed sensor unit gives an output with worst case nonlinearity of 0.28% and minimal phase-error dependence. The performance of the LDTA is tested and quantified for various other scenarios, including dynamic input conditions and sensor-unit imperfections. The superior performance of the LDTA to that of the existing techniques is also revealed in this paper.
22 citations
Cites background from "New Signal Conditioning Circuit for..."
...An analog circuit insensitive to parasitic capacitances (and phase error) was reported in [22]....
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TL;DR: In this article, a new temperature measurement method using a giant magnetoresistance (GMR) sensor based on Johnson noise thermometry (JNT) is proposed, which demonstrates its feasibility by measuring power spectral density of noise voltage in the bandwidth from 10 kHz to 22.8 kHz and resistance of GMR sensor and analyzing their relationship with the absolute temperature.
Abstract: A new temperature measurement method using a giant magnetoresistance (GMR) sensor based on Johnson noise thermometry (JNT) is proposed in this paper. This paper presents the principle of this GMR-based JNT and demonstrates its feasibility by measuring power spectral density of noise voltage in the bandwidth from 10 kHz to 22.8 kHz and resistance of GMR sensor and analyzing their relationship with the absolute temperature. The measuring errors throughout the measurement of temperature from −40 °C and 150 °C in the thermal chamber were less than ±1.8 °C with integration time of 58.6 s. Its dynamic sensing performance under both varying temperature and changing external magnetic field was characterized and demonstrated. A practical demonstration of the GMR-based JNT for measurement of surface temperature of a battery pack on an electric-vehicle testbed was also provided. Therefore, it is feasible to implement this new thermometry with a GMR sensor, making spintronic sensor multifunctional in EV applications by being a temperature sensor as well.
13 citations
TL;DR: The working principle of the LDCS is mathematically derived and explained in this paper and the dynamic performance and effect of mechanical misalignments of the combined TMR-LDCS system is revealed.
Abstract: This paper proposes a novel linear direct-digital converter for sinusoidal encoders (LDCS) to measure the angular position of a rotating shaft The outputs of a sinusoidal encoder vary as sine and cosine functions of the shaft angle The proposed LDCS, which has a low component count, processes these outputs and renders a linear accurate direct-digital output for full-circle range The LDCS is suitable for both static and dynamic measurements of the shaft angular position The working principle of the LDCS is mathematically derived and explained in this paper An elaborate evaluation of non-ideal parameters affecting the LDCS operation is carried out and reported Furthermore, the static and dynamic performances of the LDCS are verified using simulation and emulation studies The output nonlinearity obtained during emulation studies, for static measurement, is 0027 % A close agreement between simulation and emulation results is observed during these studies Later, a tunneling magnetoresistance (TMR) angle sensing unit which acts as a representative sinusoidal encoder is fabricated The LDCS is interfaced with the sensing unit, and several experimental tests are carried out The worst-case nonlinearity in the static measurement of shaft angle is 029 % Additional tests which study the dynamic performance and effect of mechanical misalignments of the combined TMR-LDCS system is also revealed in this paper
12 citations
Cites background or methods from "New Signal Conditioning Circuit for..."
...It can be seen that the newly defined vHS do not have any sharp discontinuities, as opposed to [23] and [24]....
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...An analog signal conditioner with 360° range was presented in [23]....
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...In addition, the circuits in [23] and [24] have discontinuities in the transfer characteristic of intermediate output, which makes them unsuitable for dynamic input measurement....
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TL;DR: TMR sensors excited by the altering voltage are integrated with the PMSM without taking up extra space and the rotation position is measured by counting the time pulses corresponding to the phase shift of the TMR sensor’s output signal, which is a simple and effective method to detect the position.
Abstract: Accurate rotor position is essential for a permanent magnet synchronous motor (PMSM) to execute vector control Due to the big volume, the resolver and the encoder as standard position sensors cannot be used in the space-limited application The sensor-less methods whose characteristic are sensitive to the parameter of the motor cannot be used in mass-produce Therefore, this paper presents tunnel magnetoresistance (TMR) sensors as a sensing element embedded into the PMSM to detect the magnetic field applied by the built-in magnets and high-frequency time pulses served as a measurement standard to measure the position TMR sensors excited by the altering voltage are integrated with the PMSM without taking up extra space Besides, the rotation position is measured by counting the time pulses corresponding to the phase shift of the TMR sensor’s output signal, which is a simple and effective method to detect the position Related design aspects include the corresponding signal circuit, and the sensing element is introduced in detail in this paper Experimental results prove the validity of the proposed method, and multi-group TMR sensors are used to get higher detection accuracy Although developed for the PMSM, the presented embedded position detecting approach can be used for where the space is limited or the other types of actuators to make it integration
9 citations
Cites methods from "New Signal Conditioning Circuit for..."
...Hence, various methods have been reported to accomplish a linear output, for example inverse-cosine operation [18] and complex iterative algorithm [19]....
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476 citations
Additional excerpts
...Several angle sensors suitable for automotive applications have been described in [2] and [16]....
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TL;DR: This work is trying to collect the Spanish contributions to the progress of the research related to the GMR based sensors covering, among other subjects, the applications, the sensor design, the modelling and the electronic interfaces, focusing on electrical current sensing applications.
Abstract: The 2007 Nobel Prize in Physics can be understood as a global recognition to the rapid development of the Giant Magnetoresistance (GMR), from both the physics and engineering points of view. Behind the utilization of GMR structures as read heads for massive storage magnetic hard disks, important applications as solid state magnetic sensors have emerged. Low cost, compatibility with standard CMOS technologies and high sensitivity are common advantages of these sensors. This way, they have been successfully applied in a lot different environments. In this work, we are trying to collect the Spanish contributions to the progress of the research related to the GMR based sensors covering, among other subjects, the applications, the sensor design, the modelling and the electronic interfaces, focusing on electrical current sensing applications.
214 citations
01 Sep 2000
TL;DR: Giant Magnetoresistance (GMR) and Spin Dependent Tunneling (SDT) material structures are highly sensitive to magnetic fields and can be miniaturized and integrated with silicon circuits.
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79 citations
TL;DR: A model-based diagnostic system based on a nonlinear model for predicting the pressure transients in the brake chamber that correlates the brake Chamber pressure to the treadle valve (brake application valve) plunger displacement and the pressure of the air supplied to the brake system is presented.
Abstract: The safe operation of vehicles on roads depends, among other things, on a properly functioning brake system. Air brake systems are widely used in commercial vehicles such as trucks, tractor-trailers, and buses. In these brake systems, compressed air is used as the energy transmitting medium to actuate the foundation brakes mounted on the axles. In this paper, a model-based diagnostic system for air brakes is presented. This diagnostic system is based on a nonlinear model for predicting the pressure transients in the brake chamber that correlates the brake chamber pressure to the treadle valve (brake application valve) plunger displacement and the pressure of the air supplied to the brake system. Leaks and "out-of-adjustment" of push rods are two prominent defects that affect the performance of the air brake system. Diagnostic schemes that will monitor the brake system for these defects will be presented and corroborated with experimental data obtained from the brake testing facility
71 citations
Additional excerpts
...Such transducers will have many applications including steering angle sensor [31] and brake-wear sensor (to estimate the amount of wear in automotive brakes by measuring angle of rotation of slack adjuster [32])....
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TL;DR: In this paper, the frequency-dependent impedance of magnetic tunnel junctions with MgO barriers was investigated and the capacitance of the MTJ switches from high to low when the relative electrode magnetizations change from parallel to antiparallel, opposite the resistance change.
Abstract: The frequency-dependent impedance of magnetic tunnel junctions (MTJs) with MgO barriers was investigated. The capacitance of the MTJs switches from high to low when the relative electrode magnetizations change from parallel to antiparallel, opposite the resistance change. Additionally, for parallel magnetizations, the capacitance varies with temperature though resistance remains approximately constant. The low frequency resistance and the tunneling magnetoresistance are in agreement with dc values. The capacitance is found to be larger than the expected (geometrical) capacitance, in contrast to MTJs with Al2O3 barriers. These results are explained by screening due to charge and spin accumulation at the interfaces.
66 citations
"New Signal Conditioning Circuit for..." refers background in this paper
...Parasitic capacitances are present in most of the MR sensors [38], [39]....
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