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Coreless Hall Current Sensor for Automotive Inverters Decoupling Cross-coupled Field
Abstract
Automotive inverters may require current sensors for motor torque control, especially, in applications of hybrid electric vehicles or fuel cell vehicles. In this paper, to achieve a compact, integrated and low cost current sensor, a hall current sensor without magnetic core is introduced for integrating an automotive inverter. The compactness of the current sensor is possible by using integrated magnetic concentrators based on the Hall effect. Magnetic fields caused by three-phase currents are analyzed and a magnetic shield design is proposed for decoupling the cross-coupled field. It offers galvanic isolation, wide bandwidth (>100kHz), and accuracy (< 1%). Using 2D FEM analysis, its performance is demonstrated with design parameters at a U-shaped magnetic shield. The proposed coreless current sensor is tested with rated current to validate the linearity and accuracy.
... A great proportion of this energy is consumed as AC, and it is extremely critical, therefore, to monitor the AC electricity consumption in order to establish an effective electricity management system. Various kinds of current sensor devices have been developed for different measurement applications [1][2][3][4]. Hall effect based current sensor is the main stream at the present day, but it cannot be applied directly to two-wire appliances without a cord separator or a complicated structure with algorithm. A drive voltage, additionally, is physically needed to run the Hall element based sensors and it makes the monitoring inconvenient. ...
... that the remanence of the permanent magnet is uniform and aligned in the positive y-direction. An analysis of the gradient of the magnetic field surrounding an electric power cord begins by recalling the field surrounding a single current-carrying wire are described by Equation (2): (4) Output voltage of piezoelectric film can be obtained as Equation (5) (5) t is the two times thickness of the piezoelectric film, is the width of the cantilever beam, l is the length of the cantilever beam, 31 d is the piezoelectric coefficient. The output of a piezoelectric cantilever based current sensor for three-phase four-wire appliances under symmetrical loads is a sinusoidal voltage. ...
... There are many current sensors, including Hall-effect current sensors, current transformers, shunt resistors etc. Compared with the current transformers and shunt resistors, Hall-effect current sensors are preferred because of their wide measuring range, better linearity and accuracy, good isolation between the input and output [1].The traditional Hall current sensors are divided as open loop current sensor and closed loop current sensor, in which a magnetic core with a high permeability is used to concentrate the magnetic flux generated by the primary current so that the sensors can get a high sensitivity [2,3,4]. However, in some applications where space is limited and sensitivity and accuracy are not dominantly concerned, such as a low cost servo driver, freespace current sensors can be used thanks to its simple structure, small size and low cost. ...
... Where B s , B m and B t are the simulated, measured and theoretical values of the magnetic flux density of the straight cable, respectively. Fig. 11 shows the relative error between the simulation, measured and theoretical values according to (4). B m is the average of each measured magnetic field density. ...
In this paper, simulation is done to optimize the conductor structural parameters of a new free space current sensor by using Ansoft Maxwell software. These parameters are conductor shape, gap between conductor and Hall-effect sensor, cross-section geometry and length of conductor pins, respectively. The optimized parameters are implemented in a new free-space current sensor with using a Hall-effect element. Experimental results show that the sensitivity of the new designed current sensor is relatively stable, the linearity can be controlled within ±0.6% and the total measuring error is less than 3.0%, which is lower than that of the integrated current sensor, for instance ACS756.
... There are many current sensors, including Hall-effect current sensors, current transformers, shunt resistors etc. Compared with the current transformers and shunt resistors, Hall-effect current sensors are preferred because of their wide measuring range, better linearity and accuracy, good isolation between the input and output [1].The traditional Hall current sensors are divided as open loop current sensor and closed loop current sensor, in which a magnetic core with a high permeability is used to concentrate the magnetic flux generated by the primary current so that the sensors can get a high sensitivity [2,3,4]. However, in some applications where space is limited and sensitivity and accuracy are not dominantly concerned, such as a low cost servo driver, freespace current sensors can be used thanks to its simple structure, small size and low cost. ...
... Where B s , B m and B t are the simulated, measured and theoretical values of the magnetic flux density of the straight cable, respectively. Fig. 11 shows the relative error between the simulation, measured and theoretical values according to (4). B m is the average of each measured magnetic field density. ...
... In this method, the measured current range can be adjusted via distance adjustments. However, magnetic sensors are susceptible to interference from external magnetic fields or nearby currents 254,255 and are sensitive to temperature changes. Because of this, it is difficult to measure small sensing currents. ...
Advances in micro- and nanotechnology have led to rapid employment of spintronic sensors in both recording and non-recording applications. These state-of-the-art magnetoresistive spintronic sensors exhibit high sensitivities and ultra-low field detectivities that meet requirements of smart sensing applications in the fields of internet of things, mobile devices, space technology, aeronautics, magnetic flux leakage, domotics, the environment, and healthcare. Moreover, their ability to be customized and miniaturized, ease of integration, and cost-effective nature make these sensors uniquely competitive with regard to mass production. In this study, we discuss magnetoresistive field sensors based on the planar-Hall effect, which are very promising for their high sensitivity and sensing ultra-low magnetic fields. We provide a detailed historical overview and discuss recent dramatic developments in several application fields. In addition, we discuss sensor material property requirements, design architectures, noise-reduction techniques, and sensing capabilities, along with the high repeatabilities and good flexibility characteristics of such devices. All of these high-performance characteristics apply across a wide temperature range and make the sensor robust when used in various novel applications. The sensor also appears promising because it is cost-effective and can be used in micro-sensing applications. Recently, a noteworthy study that combined integrated planar-Hall magnetoresistive sensors with microfluidic channels revealed their potential for highly localized magnetic field sensing. This characteristic makes them suitable for point-of-care-technologies that require resolutions of a few pT at room temperature.
... Circular arrays of Hall sensors have received significant attention [81][82][83][84]. The main advantage of a circular array is that it provides much better suppression of external currents than a differential sensor configuration. ...
We review recent advances in magnetic sensors for DC/AC current transducers, especially novel AMR sensors and integrated fluxgates, and we make critical comparison of their properties. Most contactless electric current transducers use magnetic cores to concentrate the flux generated by the measured current and to shield the sensor against external magnetic fields. In order to achieve this, the magnetic core should be massive. We present coreless current transducers which are lightweight, linear and free of hysteresis and remanence. We also show how to suppress their weak point: crosstalk from external currents and magnetic fields.
... Moreover, the IMC is sensitive to temperature variations. Another challenge of the open-type structure is that the open-type structure of the sensor is so vulnerable to an external magnetic field that the sensing magnetic field is highly affected by magnetic interference due to adjacent conducting lines [16,17]. Recently Allego demonstrated a 2.5 A current sensor using a differential structure with two Hall sensors in a commercial product [18]. ...
In this paper, we propose a high accuracy open-type current sensor with a differential Planar Hall Resistive (PHR) sensor. Conventional open-type current sensors with magnetic sensors are usually vulnerable to interference from an external magnetic field. To reduce the effect of an unintended magnetic field, the proposed design uses a differential structure with PHR. The differential structure provides robust performance to unwanted magnetic flux and increased magnetic sensitivity. In addition, instead of conventional Hall sensors with a magnetic concentrator, a newly developed PHR with high sensitivity is employed to sense horizontal magnetic fields. The PHR sensor and read-out integrated circuit (IC) are integrated through a post-Complementary metal-oxide-semiconductor (CMOS) process using multi-chip packaging. The current sensor is designed to measure a 1 A current level. The measured performance of the designed current sensor has a 16 kHz bandwidth and a current nonlinearity of under ±0.5%.
... I NTEGRATED CMOS Hall sensors are widely used as position sensors and magnetometers in automotive and industrial applications [1] and more recently as current sensors in energy inverter applications demanding a bandwidth greater than 100 kHz [2]. Unfortunately, planar Hall sensors experience a relative change of magnetic sensitivity caused by mechanical stress through the piezo-Hall effect [3]. ...
A magnetic sensor microsystem with Hall plates, temperature sensor, and stress sensor designed for the purpose of temperature-dependent piezo-Hall effect compensation has been implemented in 0.35 mu m CMOS technology. The sensor microsystem as well as the compensation method is entirely realized in integrated analog circuitry. A dedicated stress sensor delivers a signal proportional to the sum of in-plane normal stresses. At the systems level, the analog circuit compensates the stress-related drift of the magnetic sensitivity by adding a current proportional to the stress sensor signal on top of the Hall plate supply current. After a three-temperature calibration of a sensor molded in a SOIC-8 package extending from −40 °C to +125 °C, the residual thermal drift of the magnetic sensitivity was reduced to <0.5%. The stress-related drift due to a humidity change from humid to dry was reduced to <0.6% for samples packaged in SOIC-8 and single-in-line molded packages.
... The Hall element sensor with a magnetic yoke is currently used for sensing the motor current and the charge/discharge current of the battery. However, it is not so easy to measure the current correctly because the electromagnetic noise, which is due to very large current switching in the PCU with a rating K. Ogawa, S. Suzuki, M. Sonehara, T. Sato, and K. Asanuma, Optical Probe Current Sensor Module using the Kerr Effect of Exchange-coupled Magnetic Film and its Application to IGBT Switching Current Measurements ratio of the current sensing [2]. In addition, the Hall-effect sensor has the undesired temperature dependent drift. ...
An optical probe current sensor module using the Kerr effect of exchange-coupled magnetic film has been fabricated and applied to switching current measurements for IGBT used for the DC-DC converter and the DC-AC inverter of EV/HEV. Since the sensor module using the Kerr effect of the single domain exchange-coupled magnetic film utilizes magnetization rotation only, Barkhausen noise due to domain wall pinning can be excluded. The current sensor consists of a Laser-diode, a polarizer, a Fe-Si/Mn-Ir exchange-coupled film, a quarter-wavelength plate, PIN Photodiodes and a differential INTERNATIONAL JOURNAL ON SMART SENSING AND INTELLIGENT SYSTEMS, VOL. 5, NO. 2, JUNE 2012 347 amplifier. The current sensor has a current measurement range of ±60 A and a frequency range of DC-200 kHz. The switching current of IGBT has been measured by it.
... 시스템에 직접 저항을 접촉하는 shunt 저 항 측정법 및 비접촉식인 변압기 원리를 이용한 CT (Current Transformer) 측정법, hall effect효과를 이용한 hall IC 측정법, 자기저항효과를 이용한 MR(Magneto Resistive)센서 측정법이 있다. [4][5][6][7][8] ...
This paper proposes a low power-loss current measurement using a resistor and bypass switch. Conventional current sensing method using a resistor has a disadvantage of power loss which degrades the efficiency of the entire systems. On the other hand, proposed measurement technique operating with bypass-switch connected in parallel with sensing resistor can reduce power loss significantly the current sensor. The propose measurement works for discrete-time sampling of current sensing. Even while the analog-digital conversion does not occur at the controller, the sensing voltage across the sensor still causes ohmic conduction loss without information delivery. Hence, the bypass switch bypasses the sensing current with a small amount of power loss. In this paper, a 90[W] prototype hardware has been implemented for photovoltaic MPPT experimental verification of the proposed low power-loss current measurement technique. From the results, it can be seen that PV power observation is successfully done with the proposed method.
... An example of such a system is a three-phase 400 A current sensor for a power converter. The thickness of the U-shaped shields should be 1.5 mm to avoid saturation and to suppress the neighbouring currents by a factor of 100 (Kim et al 2009). ...
The review makes a brief overview of traditional methods of measurement of electric current and shows in more detail relatively new types of current sensors. These include Hall sensors with field concentrators, AMR current sensors, magneto-optical and superconducting current sensors. The influence of the magnetic core properties on the error of the current transformer shows why nanocrystalline materials are so advantageous for this application. Built-in CMOS current sensors are important tools for monitoring the health of integrated circuits. Of special industrial value are current clamps which can be installed without breaking the measured conductor. Parameters of current sensors are also discussed, including geometrical selectivity. This parameter specific for current sensors means the ability to suppress the influence of currents external to the sensor (including the position of the return conductor) and also suppress the influence on the position of the measured conductor with respect to the current.
An integrated Hall sensor with a 100-kHz signal-sensing bandwidth suitable for current measurements is proposed in this paper. By combining feedback technology and the bandgap compensation principle, the temperature drift of the proposed Hall sensor is compensated. Α 0.095%/°C temperature drift can be achieved over a temperature ranging from −40 °C to +125 °C. The proposed Hall sensor is implemented using 180-nm CMOS technology. The overall chip size is 3 mm², with a total current consumption of 7 mA at a 3.3-V supply voltage. Experimental chip measurements demonstrate that the proposed Hall sensor is capable of achieving an equivalent magnetic-field noise density of 114 nT/Hz and a linearity error of 1.5%.
Monitoring and analysis of power consumption are critical in terms of energy management, especially when managing the energy of factories with high energy consumption equipment. Hall sensors can be used for monitoring the power consumption. In this paper, we propose a novel superpositioning method for use with the three-phase current lines of an electrical switchboard, to improve the accuracy of current sensing by distinguishing the wanted magnetic field from magnetic interference. The relationship between magnetic interference and the magnetic field which we are trying to measure was investigated quantitatively by using numerical simulations as well as an experimental measurement. We subsequently designed a CMOS system-on-chip (SoC) for use with magnetic Hall sensors, for practical validation of the proposed method. With this technique, measurement errors were less than ±0.8 %, based on experiments conducted with 50 A flowing through a three-phase current switchboard.
A novel magnetic thin film with large anisotropy magnetic field and good thermal stability has been developed for optical probe current sensor using Kerr effect of the magnetic film. Also a sensor module has been fabricated, and its basic characteristic has been evaluated. A fabricated optical probe current sensor module consisted of a polarizer, half-wavelength plate, prism beam splitter and periodically-arrayed Fe-Si/Ru magnetic strips with a large uniaxial magnetic anisotropy field of 16 kA/m. Such large magnetic anisotropy was due to a high aspect ratio (over 1000) rectangular shape of the film. In addition, since the shape magnetic anisotropy field corresponding to the demagnetizing field in the width direction is proportional to the saturation magnetization of the film, temperature independent anisotropy can be realized at least when the ambient temperature is much lower than Curie temperature Tc of the film. In case of Fe89Si11 (at.%) with Tc of 700 degree-C, temperature coefficient of the anisotropy magnetic field was 0.03 %/degree-C small. Therefore thermal stable Kerr effect can be realized and will be useful for mobile applications such as EV/HEV. The fabricated sensor module exhibited a good linear relation between sensor output and the external magnetic field in the ranging from-16 kA/m to 16 kA/m.
This paper proposes a low power-loss averaging current mode control using a resistor and bypass switch. Generally, current sensing method using a resistor has a disadvantage of power loss which degrades the efficiency of the entire systems. On the other hand, proposed measurement technique operating with bypass-switch connected in parallel with sensing resistor can reduce power loss significantly the current sensor. An analog-circuited bypass driver is implemented and used along with an average-circuit mode controller. The bypass switch bypasses the sensing current with a small amount of power loss. In this paper, a 50[W] prototype average current mode boost converter has been implemented for the experimental verification.
A high accuracy large current sensor which can directly output the current signal without integral has been designed, fabricated, and tested. It is composed of a coreless helix coil cut by pure copper tube and a hall probe installed inside. It has excellent linear performance due to the absence of iron core. The ability of resisting disturbance is much improved because the hall probe is installed inside. A calibrated prototype sensor has been applied on a 40 T long pulsed magnetic field system to output the current data as feedback signal. A long pulse magnetic field with 25.6 T/200 ms flat-top and ripples less than 0.02% was achieved.
In this paper a statistical characterization of the spatial properties of MIMO PLC channels is provided, where the term spatial refers to the multiple input and output ports. Based on a set of channel measurements in the range from 0 to 100 MHz, the channel covariance matrices and their eigenvalues and eigenvectors are analyzed. Spatial eigenvalues can be approximated by uniform random variables while the eigenvectors can be obtained by QR decomposition of a square matrix with i.i.d. Gaussian samples. Finally the consistency between the measured and the generated spatial correlation model for power line channels is proven. Furthermore, the statistical descriptions extracted from the field measurements are used to update a previously proposed MIMO power line channel model.
This paper presents a flexible inductive coil tag for sensing the electric current in the two-wire power cords of household goods. The tag is fabricated using a complementary metal-oxide semiconductor compatible SU-8 flexible technology which provides unique device characteristics of low-cost, reliability and pervasiveness. With a 30-turns coil design in an area of 0.51 , the coil tag can provide sensitivity of 18 and 21 for detecting 50-and 60-Hz electric current in the ampere regime, respectively.
A methodology for decoupling cross-coupled fields in compact, integrated current sensor arrays is presented. The compactness of the current sensor array elements is made possible by using highly sensitive field detectors based upon giant magnetoresistive (GMR) technology, which offers galvanic isolation, small size (~mm2) and high bandwidth (>1 MHz). By using known geometric relations between the conductor geometries and locations of the field detectors, cross-coupled magnetic field signals can be used to extract necessary current signals, as well as separate unknown disturbance fields. This methodology can also be used to simplify the magnetic biasing requirements of GMR field detectors, including decoupling of the temperature dependence of the biasing magnet. Moreover, the methodology also can be extended to estimate the temperature of the magnet to provide an extra temperature signal for thermal management algorithms.
AC magnetic fields due to bus-bar currents are analyzed to design
a three-phase optical current transformer arranged longitudinally. The
optical current transformer with a single or double shield structure is
studied in order to reduce mutual interference of magnetic fields due to
three-phase transmission currents and an additional field induced by
eddy currents
Motor drive technology relies on power electronic devices and current sensors for motor control. With active thermal control of IGBT junction temperatures, the reliability and full utilization of power devices can be improved. The intent of this research is to introduce the module-level integration of the GMR field detector as both a current and temperature sensor. The integration effort also includes a new type of flexible planar interconnect to replace conventional wire bonds. The integration goal is to improve the reliability and lower the cost of motor drive systems. Cost and reliability will benefit from a lower parts count and fewer interconnections. Because of the small size, inherent galvanic isolation, temperature dependence, high sensitivity and bandwidth, the magnetoresistive field detector offers promising options for both integrated current and temperature sensing methods. This research describes the operation of GMR, as well as the necessary signal conditioning circuitry for integrated current and temperature sensing. The measured performance attributes of the sensor are also shown. Finally, future plans are discussed which involve combining the current and temperature sensing capabilities with the design of an interconnect layout and observers for junction temperature estimation.
Current sensing is one of the important functions in a dc-dc converter. It may be used for implementing current mode control or for achieving current sharing in a paralleled converters. Many current sensing schemes have been reported in literature, but they are either lossy or they require precise knowledge of the component value. In this paper, a giant magneto resistive effect based sensor is used for low voltage, high current voltage regulator module type applications. Since the current sensing is based on magnetic field, the sensing accuracy depends upon the placement of sensor on the conductor. Optimum distance is obtained for sensing the current with desired accuracy. It also gives the optimum location of the sensor to minimize the interference from closely lying current carrying conductors. Finally the performance of the sensor is experimentally verified on a 1 V/15 A buck converter switching at 1 MHz.
Electric actuators in automotive systems may require a current transducer for control purposes. A low-cost non-invasive transducer design based around a current transformer (CT) is described in this letter. The problem of droop in the output signal is addressed by controlling the CT's secondary terminal voltage in response to the core flux change. This is detected using a tertiary flux-change sense winding. The circuit is suited for use in high-temperature automotive environments. The bandwidth of the circuit is high allowing it to be used in peak current mode or hysteresis control schemes. Operation when sensing a 100-A current pulse of 10-ms duration is demonstrated
The dc and ac magnetic fields due to transmission currents flowing
through bus bars arranged side-by-side are analyzed to design the
three-phase optical current transformer. The structure of optical
current transformer with a double core for magnetic shielding is
proposed based on the analysis of the interference effect of magnetic
fields originated in the three-phase transmission currents and those of
the eddy current fields induced by the component of three-phase ac
fluxes perpendicular to the wide flat face of plate-form bus bar. It is
shown that when a value of 100 is assumed as a relative permeability for
the inner shield-core, the eddy current fields which hinder the exact
measurement of transmission currents can be decreased by less than 1/10
in the space between the inner core and the outer one, where the
magneto-optical field sensor is arranged