Search results for "Current Sensor"
showing 10 items of 22 documents
Electronic Energy Meter Based on a Tunnel Magnetoresistive Effect (TMR) Current Sensor
2017
In the present work, the design and microfabrication of a tunneling magnetoresistance (TMR) electrical current sensor is presented. After its physical and electrical characterization, a wattmeter is developed to determine the active power delivered to a load from the AC 50/60 Hz mains line. Experimental results are shown up to 1000 W of power load. A relative uncertainty of less than 1.5% with resistive load and less than 1% with capacitive load was obtained. The described application is an example of how TMR sensing technology can play a relevant role in the management and control of electrical energy.
Modeling of Magnetoresistive-Based Electrical Current Sensors: A Technological Approach
2007
The utilization of modeling tools can, in many cases, help us in the design and final prototyping of any sort of sensors. In this paper, we describe a finite-element method (FEM) model applied to a hybrid technology involving a full Wheatstone bridge spin-valve-based electrical current sensor. After validating the model against experimental results, we focus our studies on geometrical aspects of the sensor configuration, in order to detect possible deviations that may have occurred during the fabrication process. In this regard, the characteristics of the behavior of the sensor depending on lateral displacements and inclination are included. Moreover, the frequency response of the sensor is…
A Non-Invasive Thermal Drift Compensation Technique Applied to a Spin-Valve Magnetoresistive Current Sensor
2011
A compensation method for the sensitivity drift of a magnetoresistive (MR) Wheatstone bridge current sensor is proposed. The technique was carried out by placing a ruthenium temperature sensor and the MR sensor to be compensated inside a generalized impedance converter circuit (GIC). No internal modification of the sensor bridge arms is required so that the circuit is capable of compensating practical industrial sensors. The method is based on the temperature modulation of the current supplied to the bridge, which improves previous solutions based on constant current compensation. Experimental results are shown using a microfabricated spin-valve MR current sensor. The temperature compensati…
Design, fabrication, and analysis of a spin-valve based current sensor
2004
Abstract In this work, we suggest a novel current sensor design, based on spin valve technology, with a full Wheatstone bridge configuration. The principal characteristic is that the four magnetoresistance sensing elements, fully active, are deposited and patterned at the same time. This way, differences among them should be insignificant, so improving voltage offset and drift temperature parameters. The complete IC fabrication process involves only three lithography steps, making the process cheaper and faster. In order to get a balanced bridge, the measured current must be properly driven, by means of an auxiliary PCB. Some prototypes, with different input impedances, have been fabricated…
On the design of observers robust to load variations for synchronous converters
2015
Due to the ever growing concern on energy efficiency issues, synchronous rectification gained increasing attention in recent years. In the semiconductor industry fast controllers developed for DC-DC converters are typically based on inductor current measures. In this context system costs and performances strictly depend on the current sensor and its proper design. In this paper we present a sensorless synchronous approach based on a current observer. The same observer formulation is valid for the three standard DC-DC converters, simplifying its design for different configurations. Furthermore the designed observers are proven to be robust against load variations, the most uncertain paramete…
Robust current observer design for DC-DC converters
2014
In recent years several fast response controllers have been proposed for DC-DC converters. The majority of them rely on a cascade control structure involving the inductor's current in the control function as its faster dynamics, respect to output voltage, allows a significant increase in the regulation performance; the drawback is the need of a proper and expensive current sensor. In this paper a simple and robust formulation for the design of a current observer, based on the output voltage measurement is presented. The formulation is common for the three standard DC-DC converters and the resulting observer is robust to load variation. The observers have been tested in a cascade PI control …
Analytical compact modeling of GMR based current sensors: Application to power measurement at the IC level
2010
An analytical compact model for giant magnetoresistance (GMR) based current sensors has been developed. Different spin-valve based full Wheatstone bridge sensors, with the current straps integrated in the chip, have been considered. These devices have been experimentally characterized in order to extract the model parameters. In this respect, we have focused on the sensors linear operation regime. The model, which allows the individual description of the magnetoresistive elements, has been implemented in a circuit simulator by means of a behavioral description language: Verilog-A. We also propose the use of the devices in a direct power measurement application at the integrated circuit (IC)…
Analog isolated electronic dynamometer based on a magnetoresistive current sensor.
2017
In this work, an electronic system is presented to measure the force applied by a solenoid. The originality of the work is focused on the use of a magnetoresistive current sensor to provide the isolation barrier needed in the actual industrial plant where the solenoids are working. The design of the electronic system is presented as well as experimental measurements as a result of a calibration process showing a negligible hysteresis with that specific sensor. The magnetoresistive current sensor is used to develop transmission functions rather than playing its usual sensing roles.
Low cost electrical current sensors with automatic measurement range
2014
We present a simple and low cost Smart Current Sensor with wide automatic measurement range. The logic core system of the sensor is the Atmel AT32UC3C2256C AVR 32-bit microcontroller, the wireless core is a Microchip MRF24J40MA IEEE 802.15.4 RF transceiver[3]. The MCU features 11 ADC multiplexed channels, with 12-bit resolution and sample rate up to 2Msps, two of which can be sampled in parallel. The sensing board consists of two hall-effect based current sensors, assembled on different PCBs in order to perform with different sensitivities. Custom primary conductor design allowed us to sense the current flowing in the conductor with two different sensitivities: the sensor mounted inside the…
Low Cost Electrical Current Sensors with Extremely Wide Measurement Range
2015
A new electrical current measurement system is presented. It features the ability to dynamically and automatically change its measurement range to the sensed current amplitude without user action. It also exhibits galvanic isolation and near zero insertion loss characteristics.