Index terms current sensor, cross winding structure, fluxgate principle. The emphasis is given on current sensors based on magnetic materials, but other methods are also mentioned for. The objective of the tida00905 design is to provide a reference solution for accurate current measurement variant c using closedloop fluxgate magnetic current sensors. Excitation current is passed through the primary winding. Typically the hall sensor is used for large currents, and magnetoresistive sensors amr, gmr are used for higher resolution applications. A compass is one such device, one that measures the direction of an ambient magnetic field, in this case, the earths magnetic field. The ferromagnetic core is excited by the ac current i exc of frequency f into the excitation winding. The major application of fluxgate sensors is in magnetometers for the measurement of earths magnetic field. This transformer has been developed to work together with a texas instruments sensor signal conditioner, with the aim of building high precision current sensors.
Magnetic sensor systems current sensors and power metering. Although the measurement accuracy of closedloop and second harmonic based fluxgate. A fluxgate magnetometer consists of a small magnetically susceptible core wrapped by two coils of wire. Drv421 integrated magnetic fluxgate sensor for closedloop. The design of the saturable inductor current sensor is similar to that of a closedloop halleffect. A cmos analog frontend circuit for microfluxgate sensors by. This month, we put our fluxgate sensors to work and build. Ripkac a power electronics research centre, department of electronic engineering, national university of ireland, galway, ireland b department of radiology, brigham and womens hospital, harvard medical school, boston, ma, usa. Drv425 data sheet, product information and support. In this paper, a compact selfoscillating current sensor for dc current measurement with a new feedback strategy is proposed. Low cost power metering for smart grid applications. The detectable current is within a range from 6 to 600a, and is perfect mainly for industrial equipment and medical equipment that require high accuracy measurement. Current sensing for battery management system bms functions. Its normal range is suitable for measuring earths field and it.
Inside the fluxgate gradiometer popular electronics. The main advantage of closedloop fluxgate sensors is their measurement sensitivity and ability to accurately measure currents of small amplitude. During the last years, coreless current sensors based on circular arrays of magnetic field sensors have been investigated. An alternating electric current is passed through one coil, driving the core through an alternating cycle of magnetic saturation. This device provides both, a proprietary integrated. Although closedloop hall effect current sensors performs at the level of fluxgate technology at the ambient temperature of 105 c, but this technology cannot be used for high ambient temperatures of 250 c due to individual technological temperature limits. In this paper, a compact selfoscillating current sensor for dc current measurement with a new feedback strategy is pro.
Unlike a hall effect sensor, it can be extremely sensitive. The output of the sensor is a 40 to 125khz frequency that is proportional to the applied magnetic field. Fluxgate sensors and current transformers are used in applications, where resolution and stability is critical the traditional construction of the fluxgate sensor tends to be. Fluxgatebased current sensor texas instruments incorporated. For attaining better linearity of the measurement, many fluxgate sensors use the feedback mechanism to null the ambient magnetic field.
This month, we put our fluxgate sensors to work and build a practical magnetometer and gradiometer. A novel closed loop current sensor based on a circular array. In this mode of operation, where the fluxgate is used as a null detector, the current in the feedback coil is proportional to the sensed field. A fluxgate magnetometer is a device that measures the intensity and orientation of magnetic lines of flux. Sensors and actuators a 1 2004 156165 157 c r cr rs ls fluxgate current sensor square voltage source zr zs fig. Flux gate current sensor kohshin electric corporation. Figure 4 ring core, rod forster, racetrack sensor geometries figure 3 fluxgate sensors 2.
Fluxgate based, closed loop zero flux current transformer. The sensor is excited by a periodic square wave signal, sweeping the inductor across the bh curve in and out of saturation resulting in a symmetric current waveform. Today, lem uses different versions of fluxgate technologies, each. A first magnetic field produced by the current in the first region is sensed using a first magnetic field based current mfbc sensor having a first sensitivity. Figure 2 shows a method for providing an analog interface to the fgm3 and its relatives. The injected current compensates the magnetic field created by the current to be measured, and its value is proportional to this current. Dec 19, 2018 a novel closed loop current sensor based on a circular array of magnetic field sensors abstract. To enable applications with enhanced performance, current. Flux gate sensors or saturable inductor current sensors work on the same measurement principle as halleffectbased current sensors. Its normal range is suitable for measuring earths field and it is capable of resolving well below one 10,000th of that. The measurement of the magnetization of a magnetic material like a ferromagnet is an example. Analysis and design of a selfoscillating bidirectionally. Fluxgate hmc2003 2n6028 application note tilt sensors degree 3 axis fluxgate compass 3 axis compass abstract of gps vehicle location tracking system fluxgate magnetometer car sensor parking text.
Sensors free fulltext rectangular array electric current. The secondary coil picks up the imbalance in the magnetic flux due to the ambient magnetic field which acts. A conventional fluxgate sensor typically comprises a core in a soft magnetic material of high magnetic permeability that is subjected to an alternating magnetic field by an excitation coil of the fluxgate. Integrated microfluxgate sensors have been developed in recent years. There are several types of contactless current sensors. Drv425 fluxgate magneticfield sensor datasheet rev. A cmos analog frontend circuit for microfluxgate sensors. In order to increase the dynamic range of packaged current sensor 800, fluxgate sensors 811814 are positioned on the parallel portions 806809 so that a portion of current 230 flows around the sensors as indicated by current path 831 and a portion bypasses the sensors as. Research on the simplified directcurrent fluxgate sensor and. Electrical current sensor comprising a measuring circuit and an inductor for measuring a primary current i p flowing in a primary conductor over a current range from a minimum specified current amplitude to a maximum specified current amplitude, the inductor comprising a saturable magnetic core made of a highly permeable magnetic material and a secondary coil for. Current sensors are available at mouser electronics from industry leading manufacturers. Novel rectangular yokeless current transducer with the range 400 a using 16 microfluxgate sensors around the busbar conductor is presented in this paper. The emphasis is given on current sensors based on magnetic. Drv421 integrated magnetic fluxgate sensor for closedloop current sensing.
A magnetometer is a device that measures magnetismthe direction, strength, or relative change of a magnetic field at a particular location. Frequency deratings apply, see mfg user manual for full set of specifications. A flux gate current sensor has basically the same structure as a current sensor with a magnetic balance system, except that it has a magnetic probe coil instead. Sensitivity andphase plane analysis zucheng gao, member, ieee, and r. This sensor enables electricallyisolated, highsensitivity, and precise dc and acfield measurements. It creates a compensating magnetic field by passing dc current through a separate coaxial feedback coil to the sense coil or by passing dc current back to the sense coil itself 10. Rectangular array electric current transducer with. Pcb fluxgate current sensor with saturable inductor. Magnetometers are used in navigation systems and electronic compasses. The present invention relates to a closedloop current sensor, in particular of the fluxgate type. The technique improves linearity of measurement, allows a much greater dynamic range.
Fluxgate sensors fluxgate sensors are a saturable inductor constructed of a magnetic core and wound coil. The third current sensor is not necessary in this case either. Design of a dc current sensor based on fluxgate principle conference paper pdf available in aip conference proceedings 211. The current measurement range can be fixed by setting the value of resistance of the shunt resistor. A novel closed loop current sensor based on a circular array of magnetic field sensors. The injection of current in an auxiliary winding creates a compensating magnetic field that restores the symmetry of the hysteresis cycle. Fluxgate main principle uses a saturable inductor for sensing the field produced by an external current. By measuring the magnetic field around a conductor, the current level can be accurately predicted. Open loop hall effect, differential fluxgate based current sensing. Compared to yokeless transducers utilizing the differential pair of magnetic sensors, our solution has much better suppression of the external currents lower crosstalk.
Fluxgate magnetometers have been used by robotic space probes to analyze, map and monitor the magnetic fields of the earth and other planets. It converts the duty cycle variation of the excitation. Addressing highvoltage current sensing design challenges in hevevs. Investigating fluxgate current sensors dc capable with detours into analog electronics and switched mode power supplies. Fluxgate sensors and current transformers are used in applications, where resolution and stability is critical. This device provides both, a proprietary integrated fluxgate sensor, and the required analog signal conditioning, thus minimizing component count and cost. Fluxgate magnetometers evolved during the second world war as a means of detecting submarines. Closedloop fluxgate current sensor lem intellectual. The temperature variation i o t of the electrical offset current i o e is the variation of the electrical offset from 25 c to the considered temperature. Thus, the main idea of automatic 30 40 50 60 compensation is to synchronize the free running counter with excitation current. Research on the simplified directcurrent fluxgate sensor. Pdf design of a dc current sensor based on fluxgate.
High current measurement application guide yokogawa. Fluxgate current sensor uses a high permeability magnetic. Its normal range is suitable for measuring earths field and it is capable of resolving well below one 10,000 th of that. This article presents the design and implementation of a transducer system for the measurement of ac and dc highcurrent using the flux compensation technique in the measurement transformer, also called fluxgate technology. The sensor core used here consists of high gradient hysteresis curve and of very low power loss. A novel closed loop current sensor based on a circular. Fluxgate magnetic current sensing with high linearity for.
Selfcompensating excitation of fluxgate sensors for space. Us20170059627a1 us14986,121 us201514986121a us2017059627a1 us 20170059627 a1 us20170059627 a1 us 20170059627a1 us 201514986121 a us201514986121 a us 201514986121a us 2017059627 a1 us2017059627 a1 us 2017059627a1 authority us united states prior art keywords current mfbc sensor region magnetic field prior art date 20150824 legal status the legal status is. The electrical offset current i o e is the residual output current when the input current is zero. A new compact fluxgate current sensor for ac and dc application article pdf available in ieee transactions on magnetics 5011. This paper gives a comparison between circular arrays built from hall and fluxgate magnetic field sensors in both the closed loop and open loop operation. If closed loop configuration fluxgate sensors are used, instead of hall sensors, the measurement. The electronic operation of these sensors is generally the same as normal fluxgates. You should choose a current sensor to suit the application in which you plan to use it, based on an understanding of the differences among the various methods of measuring currents, including the hall element method, the rogowski method, and the zeroflux method. Compared to industrial transducers with yoke, the new transducer has 15. Oct 03, 2017 in order to increase the dynamic range of packaged current sensor 800, fluxgate sensors 811814 are positioned on the parallel portions 806809 so that a portion of current 230 flows around the sensors as indicated by current path 831 and a portion bypasses the sensors as indicated by current path 832. Operating a current sensor by conducting a current serially through a first region and a second region of an electrically conductive member. A flux gate current sensor has basically the same structure as a current sensor with a magnetic balance system, except that it has a magnetic probe coil instead of a hall element.
Various types of fluxgate magnetometer sensors are designed and developed for the determination of very weak magnetic field. Fluxgate magnetometer designs fall into broadly two styles, those employing rod cores and those using ring cores. The fluxgate magnetometer is a magnetic field sensor for vector magnetic field. The traditional construction of the fluxgate sensor tends to be complicated and expensive. Military applications continue to be an important market, but geologists and archeologists have also become big fans of these robust and extremely sensitive instruments. The core permeability t is therefore changing with 2f frequency. Currently, the fluxgate sensor excitation and detection control circuitry is based on digital counters dividing a clock frequency from a crystal oscillator, hencethephaseshift is set to a fixed value.
Doncaster russell abstractin a previous paper 1 wehave shownthat the transient ment, is economical to manufacture, and has low power behavior offluxgate sensors in magnetometer andin gradiometer can requirements. Leakage current sensors industrial monitoring and control systems overcurrent detection frequency, voltage, and solar inverters 3 description the drv421 is designed for magnetic closedloop current sensing solutions, enabling isolated, precise dc and accurrent measurements. Drv425drv425q1 fluxgate magnetic field sensor ti mouser. Design of fluxgate magnetometer sensors semantic scholar.
They are most frequently used where low power and low noise are the overriding. Indicates the realtime current flowing through the battery, which would be used to calculate the start of charge of the battery. Pdf a new compact fluxgate current sensor for ac and dc. They are also used in geological prospecting, aerospace navigation. Sumida corporation has developed a new transformer for use in fluxgate current sensors targeted at the industrial power electronics market. Sensors and actuators a 123124 2005 430437 application of. Texas instruments drv425drv425q1 precision fluxgate magnetic field sensor is designed for singleaxis, magneticfield sensing applications. The sensor consists of a magnetic core with compensation winding interfaced to driver ic with a builtin fluxgate sensor. Doncaster russell abstractin a previous paper 1 wehave shownthat the transient ment, is economical to manufacture, and has low power behavior offluxgate sensors in magnetometer andin.