Tunnel Magnetoresistance-Based Noncontact Current Sensing and Measurement Method

An optimal slip control algorithm has been proposed in this paper to improve the driving performance of a mobile robot in outdoor environments. The optimal slip control is aimed to achieve a straight line driving accurately by minimizing the slip. The slip is occurred by dynamic characteristics of the mobile robot and external environmental factors, which has a critical effect on the straight line driving efficiency. To reduce the slip, an ASS(Anti Slip System) has been implemented using FSC(Fuzzy Slip Control) where encoder and current sensor data are properly used not to cause cumulative errors. To demonstrate superiority of the proposed control algorithm, real experiments are performed using a mobile robot in the outdoor.

The flexible eddy current array sensor has the characteristics of flexibility, bendability and light weight, which has a great application prospect in the field of structural health monitoring. The traditional flexible eddy current array sensor is affected by the skin effect and the crack monitoring depth is relatively low. This paper proposes an eddy current array sensor which uses TMR (tunnel magneto-resistance) sensor as sensing channels. It reduces the excitation frequency and increases the eddy current skin depth. The TMR sensor realizes the quantitative monitoring of cracks by the array arrangement. First, the finite element model of the sensor is established, and the influence of the cracks on the different layers of the multilayer structure on the magnetic induction intensity at the test point is analyzed. The simulation and results show that when the crack passes through the sensor, the magnetic induction intensity at the three test points changes in sequence and gradually increases to the maximum value. The direct relative position of the maximum value of the three test points is approximately the same as the distance among the test points. Then, the simulated crack growth experiment of the corresponding sensor is carried out. The experimental results show that as the crack grows, the signals of the three TMR sensors on the eddy current sensor change in sequence, and the distance between the characteristic points is consistent with the distance between the TMR sensors. The output voltage of the sensor decrease with the crack depth increases. The experimental results are consistent with the simulation results, which further verifies the correctness of the simulation model.

Aiming at the problem that the current measurements provided by phasor measurement unit (PMU) is difficult to introduce to traditional state estimation, a new method to solve the compatibility problems of PMU and supervisory control and data acquisition (SCADA) is presented in this paper. By the rotated-pseudo-measurement (RPM) method, current measurements are transformed into the pseudo measurements and decoupled in polar coordinates, so that they could taken into nonlinear state estimation. Then the RPM method is simulated compared with the current transformation (CT) method. According to the result, it is showed that the RPM method has many advantages compared with the CT, such as independence of other measurements, small error in propagation and more significant in improving estimation accuracy. Moreover, the RPM method has the compatibility with traditional nonlinear state estimation and the fast calculating speed, which have good prospects of practice.

With the continuous development of power electronic power systems, the dynamic characteristics of power systems become much more complex, which may cause wide-band oscillation problems. However, due to the constraints of Nyquist sampling theorem and communication bandwidth, it is difficult for the existing dynamic monitoring devices to transmit and monitor wide-band oscillation signals. In this paper, a method for wide-band oscillation data compression and restoration identification based on autoencoder is proposed. Firstly, the encoder is used at the sub-station to reduce the dimension of the measurement data. On the one hand, it is convenient to carry out the wide-band oscillation signal transmission with the existing bandwidth. On the other hand, it also effectively reduces the redundancy of the oscillation data. On this basis, the master station uses the decoder to restore and identify the uploaded compressed data, which can not only verify the effectiveness and accuracy of the proposed method, but also enable the master station to conduct a more comprehensive monitoring and analysis of wide-band oscillation. Finally, case study is carried out in the four-machine and two-area system with a wind farm. The results show that the method can be applied to the data transmission of subsynchronous, supersynchronous and even medium/high frequency oscillation, and has high restoration accuracy and good anti-noise performance.

To guarantee renewable energy resources accommodation of power system, the use of energy storage facilities has become an inevitable trend. Owing to the various operation restrict of different energy storage facilities, it’s difficult to realize the stable operation and the renewable energy accommodation of the power system with only one kind of energy storage facility. To solve this problem, the dynamic characteristics of power system with various types of energy storage devices are studied in this paper. Through the Individual Based Model (IBM) method, the dynamic model of power system under the background of large-scale renewable energy accommodation is established. This model is tested in typical situations, and the precision and computation efficiency of the IBM are proved.

Purpose This paper aims to design and investigate a high-precision tunneling magnetoresistance (TMR) noncontact current sensor based on a dual-gap anti-interference structure, to address the susceptibility of traditional TMR current sensors to external interference in complex electromagnetic environments. Design/methodology/approach A systematic methodology integrating theoretical modeling, finite element simulation and experimental validation was used. A mathematical model of the dual-gap magnetic circuit was established based on magnetic Ohm’s law to analyze its differential output mechanism for suppressing common-mode magnetic field interference. Key parameters such as magnetic core cross-section and air gap dimensions (a = b = 7 mm) were optimized through finite element simulation, evaluating magnetic field uniformity and conductor displacement error. Thermal performance and anti-interference capability were experimentally validated under controlled conditions. Findings The optimized dual-gap structure improves magnetic field uniformity to 0.0010 and reduces measurement error caused by conductor displacement to below 0.08%. It also demonstrates superior thermal management, lowering temperature rise by 27.4% compared to a single-gap structure under high load. Under an external interference field of 10 Oe, the dual-gap sensor achieves an output voltage error of 0.014%, outperforming the single-gap design (0.017%). The sensor maintains a linearity of ± 0.5% and an accuracy of ± 1% across a temperature range of –50°C to 70°C. Originality/value This study proposes an innovative dual-gap magnetic circuit structure that effectively enhances anti-interference performance and thermal stability in TMR current sensors. The research provides a practical and reliable design pathway for developing high-precision, robust current sensors suitable for demanding electromagnetic environments.

Current sensing is an integral part of most power electronic systems. For increased power density and galvanic isolation, module integrated current sensing using Giant Magnetoresistance (GMR) Point Field Detectors (PFDs) has been demonstrated. In this paper, submillimeter 2D Tunnel Magnetoresistance (TMR) PFD is characterized for galvanically isolated current sensing. TMR properties that make it superior to AMR and GMR are evaluated. The 2D field shaping and characterization methodology is developed, and 2D PFDs are used in compact integrated current sensing in busbars. It is demonstrated how the 2D Magnetoresistance (MR) PFDs can inherently provide disturbance decoupling with fewer PFDs than 1D MR PFDs, in power dense traction applications.

Traditional current transformer and Hall current sensor possess several drawbacks such the remanence, magnetic saturation and core losses. A novel non-contact type of current transducer based on the tunneling magneto-resistance (TMR) effect is presented to solve these problems. Due to the high sensitivity and low hysteresis of the TMR, the magnetic field concentrator can be canceled, therefore, no remanence occurs. Using PCB-IC mixed technology, a novel non-contact type of current transducer based on the tunneling magneto-resistance (TMR) sensor is designed, in which the TMR sensors were configured as a Wheat stone bridge. The bridge excitation circuit with temperature compensation, and the conditioning circuit with a closed loop controller is described. In a setting-4.0A-4.0A range, the full scale output of the designed prototype is 1.30 V, the static accuracy is 0.0923% F.S., linearity is 0.0550% F.S., Hysteresis Error is 0.0712% F.S. a frequency response up to 1MHz has been obtained.

Silicon carbide (SiC) <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s offer significant advantages in terms of improved efficiency and reduced size of power electronic converters. However, they possess lesser short-circuit withstand time than silicon devices. An ultrafast short-circuit protection scheme for TO-247 packaged SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s is presented in this article. The protection scheme utilizes printed circuit board (PCB) coils to sense the rate of change of current through SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s in a half-bridge circuit. The PCB coils are fabricated near a single interconnect trace between the power device and the dc busbar. To ensure minimal intrusion inside the power-loop, the methodology of selecting the minimum trace length for a desired mutual inductance between the coil and the interconnect trace is presented through finite-element analysis. Experimental results for an SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> subjected to a hard switched fault and a fault under load are presented, and the protection circuit response time under 25 ns is reported. Lastly, the peak current-mode control of a buck converter is implemented using the designed PCB coil-based sensor as current feedback sensor. Therefore, the PCB coil is demonstrated to be an effective alternative for Hall effect and magnetic core-based sensors in current control applications with dc/dc converters.

Modeling and analysis of printed circuit board (PCB) based coils as current sensors is presented. The layout of a printed coil realization with interleaved winding is presented along with its performance characteristics. Immunity to external magnetic fields for both single and differential coils are investigated. The differential PCB coil is a variant of the Rogowski coil, having the return coil realized as a PCB with turns similar to the forward coil. The printed coil designs are analyzed using a magneto-quasi-statics based simulation tool. The mutual inductance of both the single printed coil and differential Rogowski coil obtained using simulations are in agreement with the measurement results leading way to the investigations on the immunity of printed coils to external magnetic field through simulations.

In this paper, we present a new technique to unify and intensify the magnetic fields that results in higher performance of Anisotropic Magneto-Resistive (AMR) current sensors and consequently develop a closed loop controller for 100W synchronous GaN buck converter at 1MHz. The closed loop operation of high switching frequency converters at high power has always been a big challenge due to lack of access to current information. The proposed method that also intensifies the magnetic fields through the sensor, significantly improves the bandwidth limits, and reduces electromagnetic interference (EMI) on AMR sensors, making them applicable for high switching frequency and high current power electronics converters. After verifying uniform distribution concept through simulation, we also implemented a prototype of AMR current sensors onto Printed Circuit Board (PCB) for verification of the concept at high frequency converter. We then present the design procedure and associated challenges of an integrated analogue peak current controller for creating the closed loop operation of a GaN buck converter at high switching frequency.

A low-inductive half-bridge and gate driver package with on-package gate and dc-link capacitors is realized by printed circuit board (PCB) embedding of two GaN-on-Si ICs. While monolithic half-bridge and driver integration reduces on-chip parasitics, it does not solve the interconnection challenge to external capacitors. This letter solves this issue through advantageous combination of PCB embedding and monolithic circuit integration. This letter uses GaN-on-Si power circuits with integrated gate drivers, freewheeling diodes, and temperature and current sensors. GaN ICs are fabricated with thick copper on both sides, which makes them applicable to commercial PCB-embedding technologies. Thermal aspects are discussed and electromagnetic simulations used to compare the PCB-embedded package to a bond wire based package. A PCB-embedded dc-dc converter is operated up to 350 V and 450 W with up to 98.7% efficiency. 380 V hard-switching transitions show below 8% over- and undershoot despite over 120 V/ns slew rates. Parallel platelike placement of silicon flip-chip capacitors above the gate driver final stage transistors and separated only by a thin PCB layer increased the gate-loop parasitic inductance by only 40 pH.

Purpose – The purpose of this paper is to develop a novel technique for the pre-design of a printed circuit board (PCB) of a DC-DC power converters where the placement of electric components can cancel the electromagnetic emissions through subtractive coupling and in this sense to minimize the stray magnetic and electric fields at a specific location. For this work the location of interest is a current transducer used for control purposes positioned in the center of a DC-DC Cuk converter board as a constrain. Design/methodology/approach – The methodology of design is based on the development of an interface software platform through MatLab script coding which interconnects the solution of a numerical analysis software and an optimization technique. The numerical analysis software is based on finite element calculations where quasi-static field analysis are performed to calculate the radiated electric and magnetic fields. The optimization technique is conducted by genetic algorithms (GAs). Findings – The r...

Magnetoelectric (ME) composites have been proven to apply to current sensors. However, the previously reported ME materials-based current sensors mainly focus on direct current and sine alternating current sensing, which put a critical limit on the measurement of transient current. In this paper, a cylindrical ME composite consisting of a magnetostrictive Fe83Ga17 (FeGa) cylinder and a piezoelectric Pb(Zr, Ti)O3 (PZT) circular tube is fabricated for lightning current sensing applications. The time-domain output voltage of the FeGa/PZT composite is simulated and measured in detail. Under the excitation of 8/20 µs lighting current, the output voltage of the composite can change with the current. But the damping oscillation at its resonant frequency is observed. Furthermore, to obtain an obvious ME response, the FeGa/PZT cylinder and current-carrying wire should be arranged closely and in an orthogonal way. When the amplitude of 8/20 µs lightning current is in the range of 500 A–9 kA, the ME FeGa/PZT composite shows a sensitivity of 1.36 mV A−1, a linear response (R 2 = 0.9993), and a small return error (0.12 V). These results provide that the ME composite is suitable to be used in non-contact lightning current measurements.

In this letter, we propose a noncontact method for simultaneously measuring the current and voltage change rates by Rogowski coils. The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dv/dt</i> measurement capability is achieved based on electric field coupling, which is incorporated into the state-of-the-art Rogowski coil-based current sensing solutions. The application of the proposed method for power semiconductor devices is demonstrated by a case study of an insulated gate bipolar transistor (IGBT) switching circuit. The Rogowski coils are integrated with a printed circuit board (PCB) and fit with the IGBT module terminals. The comparable results from high-performance commercial instruments verify the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">di/dt</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dv/dt</i> measurement accuracy of the presented compact and cost-effective solution.