• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.11
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• pp.1894-1899
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• 2016

In this paper, because the position sensor represents the important factor in BLDC (Brushless DC) motor drives, BLDC motor is necessary that the three Hall-sensors evenly be distributed around the stator circumference in case of the 3 phase motor. The Hall-sensor is set up in this motor to detect the main flux from the rotor. So the output signal from Hall-sensor is used to drive IGBT to control the stator winding current. However, in case of breakdown Hall sensor, we research that the estimation algorithm of Hall sensor signal to detect rotor position and for the speed feedback signals with BLDC motor whose six stator and two rotor designed. In addition, this paper presents a sensorless speed control of BLDC Motor using terminal voltage of the one phase. Rotor position information is extracted by indirectly sensing the back EMF from only one of the three terminal voltages for a three-phase BLDC motor.

• Korean Journal of Materials Research
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• v.4 no.1
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• pp.113-116
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• 1994

InSb thin film magnetic sensor, which have been prepared on glass substrate by vacuum evaporation, is investigated in this paper. The dependance of Hall voltage on magnetic field and temperature is examined by Hall effect. The variation of Hall voltage with magnetic field is almost linear at constant current drive but it is deviated from the linearity at constant voltage drive. Hall voltage decreases as the ambient temperature increases, so it is necessary to take into account the temperature effect when the InSb thin film is used as magnetic sensor.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.4
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• pp.358-363
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• 2006

This paper demonstrates a new non-contact electronic joystick using single hall sensor which detects a horizontal vector of the magnetic field. Furthermore, in this paper, it is mathematically modeled that nonlinear characteristics between the output of hall sensor and the movement of joystick bar. The dynamic horizontal vector of magnetic flux is detected by the hall sensor while a permanent magnet is rotated with the joystick bar, which has two dimension detecting area. Using the nonlinear adjustment equations, the output signals of hall sensor have been linearized to give higher accuracy in the two dimension movement. Finally, through the real experiments, it is showed that the single hall sensor structure mechanism is superior to the dual sensor structure in sensing the two-dimensional motion without offset.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.3
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• pp.205-210
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• 2013

This paper presents a novel hall sensor fault detection and fault-tolerant control method for a high-speed permanent magnet synchronous motor (PMSM) drive system. A phase locked loop (PLL) type position estimator is used with a conventional interpolation based rotor position estimator to reduce position errors due to misalignment of hall sensors. The expected trigger time of hall sensor's output is used for detecting hall sensor fault condition and the PLL type position estimator is reconfigured for fault-tolerant control at the hall sensor fault condition. The proposed method can minimize current ripples during the transition from sensored control using hall sensors to sensorless control. Experimental results have been proposed to prove the validity of the proposed method.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.5
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• pp.152-159
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• 2016

This paper describes an offset and 1/f noise cancellation technique based hall sensor signal processor. The hall sensor outputs a hall voltage from the input magnetic field, which direction is orthogonal to hall plate. The two major elements to complete the hall sensor operation are: the one is a hall sensor to generate hall voltage from input magentic field, and the other one is a hall signal process system to cancel the offset and 1/f noise of hall signal. The proposed hall sensor splits the hall signal and unwanted signals(i.e. offset and 1/f noise) using a spinning current biasing technique and chopper stabilizer. The hall signal converted to 100 kHz and unwanted signals stay around DC frequency pass through chopper stabilizer. The unwanted signals are bloked by highpass filter which, 60 kHz cut off freqyency. Therefore only pure hall signal is enter the ADC(analog to dogital converter) for digitalize. The hall signal and unwanted signal at the output of an amplifer and highpass filter, which increase the power level of hall signal and cancel the unwanted signals are -53.9 dBm @ 100 kHz and -101.3 dBm @ 10 kHz. The ADC output of hall sensor signal process system has -5.0 dBm hall signal at 100 kHz frequency and -55.0 dBm unwanted signals at 10 kHz frequency.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.5
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• pp.866-874
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• 2008

Motor frequency can be measured by a hall sensor. Among the many hall sensors, a linear type hall sensor is good at high accuracy frequency measuring problem. However, in general, this linear type hall sensor has DC offset which can vary along sensor's operating voltage change. Therefore, In motor frequency measurement problem using the linear hall sensor, it needs an estimator that can estimate frequency and DC offset simultaneously. In this paper, we propose the least mean square estimator to estimate motor frequency. To verify its performance, we compare the LMS estimator with a commercial analog tachometer. Experimental results shows the proposed LMS estimator works well in varying frequency and stationary DC offset.

• Journal of Sensor Science and Technology
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• v.14 no.2
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• pp.85-90
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• 2005

In this study, we have fabricated a three branches vertical Hall sensor for detecting three phases rotation informations of miniaturized brushless motor. The sensor gives three position signals phase shifted by $120^{\circ}$, corresponding to the motor driving signals. The branch has one Hall output and one input each other. The central part acts as common driving input. Sensor has branch width of $150{\mu}m$ and distance from central electrode to Hall electrode of $100{\mu}m$. The sensitivity of sensor is 250 V/$A{\cdot}T$ at magnetic field of 0.1 T. It has also showed three sine waves of Hall voltages with $120^{\circ}$ phase over a $360^{\circ}$ rotation. A packaged sensing part are $2{\times}2mm^{2}$ and has been successfully tested on a motor rotation at a speed up to 60,000 rpm.

• Electrical & Electronic Materials
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• v.8 no.2
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• pp.165-170
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• 1995

This paper describes the fabrication and characteristics of a Si Hall sensor fabricated on a SOI (Si-on-insulator) structure. The SOI structure was formed by SDB(Si-wafer direct bonding) technology and the insulator of the SOI structure was used as the dielectrical isolation layer of a Hall sensor. The Hall voltage and sensitivity of the implemented SDB SOI Hall sensors showed good linearity with respect to the applied magnetic flux density and supplied current. The product sensitivity of the SDB SOI Hall sensor was average 600V/A.T and its value has been increased up to 3 times compared to that of bulk Si with buried layer of 10.mu.m. Moreover, this sensor can be used at high-temperature, high-radiation and in corrosive environments.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.9
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• pp.840-845
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• 2005

A three branches vortical Hall sensor for detecting rotation angle of brushless motor has fabricated. The sensor is constructed three branches of $150{\mu}m$ width and $300{\mu}m$ distance from central electrode to Hall electrode. Each branch has one Hall output and one Hall input. The central electrode acts as common driving input. According to rotation angle change of brushless motor, sensor gives three position signals phase shifted by $120^{\circ}$. The sensitivity of sensor is 200V/A$\cdot$T at magnetic field of 0.1 T and constant driving current of 1mA. It has also showed three sine waves of Hall output voltages with $120^{\circ}$ phase over one motor rotation. The noise can limit sensor's resolution. We have measured sensor's noise characteristics. The detectable minimum magnetic field is $20{\mu}T$ at driving current 1mA, measured frequency 1 kHz and bandwidth$({\Delta}f)$ of 1Hz.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.6
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• pp.490-495
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• 2016

Pulsed eddy current (PEC) testing signals have typically been obtained from the electromotive force induced in a sensor coil. However, an increasing number of studies have elected to incorporate the Hall plate as a sensor. Thus, accurate numerical modeling of the Hall sensor signal is necessary. In this study, a PEC probe is designed and a numerical modeling program is written so that Hall sensor signals and coil sensor signals can be calculated simultaneously. First, a step current is used as the input current. The predicted Hall sensor signals show similar characteristics to those of the experimental signals reported by other researchers. The characteristics of the two types of signals are then analyzed and compared as the thickness of test object changes. The results show that the Hall sensor signal provides less information for evaluating the thickness of the test object than the coil sensor signal. The response signals from a pulsed input current are also calculated, and it is confirmed that an equivalent reversed signal pattern appeared after the pulse width at both signals.