The current sensor based on the principle of fluxgate is characterized by high linearity, accuracy and wide frequency band, widely used for precise measurement AC DC current. Derive magnetomotive force balance equation analyze excitation cancellation mechanism. According to method, was divided into two types: external type self type. research progress at home abroad elaborated, including application fields, structural principle, key technical indicators, main innovation points. Clear...

We presented a theoretical study on the spin-polarized transport of one single-molecule magnet. The results show it has spin filter behavior, and can also be used as molecular valve with large abnormal magnetoresistance, which is an excellent candidate for spintronics devices. It found that steplike features negative differential resistance in I-V curve indeed originate from discreteness narrow density states levels.

Heterogeneous strong base catalysts possessing ordered nanoporous structure are highly expected due to their high activity and shape selectivity in diverse reactions. However, fabrication remains a great challenge because quite temperatures (600–700 °C) compulsory for the generation of basicity on conventional materials (i.e., zeolites mesoporous silicas). Here, we report first time direct basic sites metal–organic frameworks (MOFs) by using guest–host redox (GHR) interaction between...

The spin-polarized transport properties of a high-spin-state spin-crossover molecular junction with zigzag-edge graphene nanoribbon electrodes have been studied using density functional theory combined the nonequilibrium Green's-function formalism. presents integrated spintronic functionalities such as negative differential resistance behavior, spin filter and rectifying effect, associated giant magnetoresistance effect by tuning external magnetic field. Furthermore, are almost unaffected...

A new generation of adsorbents is designed by grafting smart molecular gates onto the orifices mesopores. The are reversibly closed/opened according to adsorption/desorption conditions. can thus realize both selective adsorption and efficient desorption, which extremely desirable for adsorptive separation but unlikely conventional with fixed pore openings. As a service our authors readers, this journal provides supporting information supplied authors. Such materials peer reviewed may be...

This paper carries on the research sensorless control of dual three-phase (DTP) permanent magnet motor (PMSM) at low speed. If high frequency voltage signal is injected into one set stator windings, it can achieve well control. The mathematical model DTP PMSM obtained from d-q synchronous frames theory. One cosine γ axis ABC windings. rotor position error estimated current responses. experiments results are carried for verification designed method.

In this paper, a PWM modulated Three-Level single-phase grid-connected inverter is proposed for photovoltaic (PV) generation system to reduce ripple of the current injected into grid and voltage stress on switches To achieve high quality output sinusoidal current, Proportional-Resonant (PR) controller applied PV inverter. Moreover, dynamic compensator used THD current. Simulation results are provided testify validity feasibility scheme.

Mathematical model of magnetic modulator was established, characterized by the consistency with actual structure, which is two cores differential structure and excitation winding doubling as detection winding. Simulate analyze influence source (sine wave, triangle wave square wave) saturation depth core on output voltage The result shows that characteristic optimal when employing source. Meanwhile, working in over saturated state will lead to oscillation waveform.

In order to reduce the torque ripple of Permanent Magnet Synchronous Motor (PMSM) with model predictive control (MPC), a PMSM dual (Dual-MPC) strategy within two steps is proposed in this paper. First, extends basic voltage vector generalized double vectors suppress compared conventional duty cycle MPC strategy. Then, Dual-MPC consists processes, which selecting each period and then calculating their time. To validate strategy, simulation experiment are carried on. With results flux circle,...

The demodulation circuit is a major part of DC current comparator (DCC), which performance directly influences the accuracy, sensitivity and noise whole system. Separately describe working principle two methods, based on corresponding circuits were designed; experiments simulation studies carried out. research results show that both methods can realize function converting even harmonic signals characterizing measured to voltage. important advantage peak difference it demodulate all signals....

This paper proposes a direct injection-locked frequency divider (ILFD) with wide locking range in the Ka-band. A complementary cross-coupled architecture is used to enhance overdriving voltage of switch transistor so that extended efficiently. New insights into and output power are proposed. new method analyze optimize injection sensitivity presented layout technique reduce parasitics transistors applied decrease shift degradation. The circuit designed standard 90-nm CMOS process. total ILFD...

Resonant controllers can be utilized in the variable frequency control system of permanent magnet synchronous motor (PMSM) to suppress current harmonics for its capacity on extracting signals specific frequency. However, performance resonant high-order suppression weakened by limited bandwidth system. This paper improves space vector pulse width modulation (SVPWM) algorithm asymmetric-SVPWM (ASVPWM) and combine it with expand promote suppressing harmonics.

Advanced design and operation consideration for the close-connected winding permanent-magnet brushless DC machine is proposed in this paper, including circulating current elimination, fault-tolerant control breakdown of a power electronic switch, sensorless method. With finite-element analysis, influence parameters on investigated. By properly controlling status switches, coils being connected into equivalent circuit can be changed to avoid failure switch. Sensorless explored by detecting...

For realizing finer granularity rate adaptation with tradeoff between visual quality and network bandwidth, DASH provides sub-representation structure that can further refine QoE options multiple temporal operating point at a fixed spatial quality, i.e., PSNR. In order to facilitate streaming driven decisions sub-representations, in this paper, we shall develop new for constructing sub-representations. Besides, utilize the fame significance metric characterize introduce gradient layer...

The performance of electronic transformer (ET) directly influences power measurement accuracy, which output mode is quite different from that electromagnetic transformers. Thus, conventional calibration method not suitable for testing ET. This paper starts with the definition ration error and phase by IEC standard; analyzes problems in existing methods then innovatively puts forward employing standard current (CT), precise shunt oscilloscope to measure ratio ET analog signal at frequency...

In order to improve the measurement performance characterized by sensitivity and drift value of DC current comparator, this paper analyzed two kinds differential structure cores; constructed device formed excitation voltage source, oscilloscope, peak difference demodulation circuit meter. Through formula derivation, it was proved that winding can play role detection output is still an even harmonic function. This simplified reduce leakage flux accordingly accuracy ratio. Meanwhile, pairs ten...

In virtue of modern control theory, combining with the analysis structure and principle direct current comparator (DCC), relative error formula ratio was derived to theoretically analyze steady state value. Resolve each part transfer function then compound closed-loop function. Employ Nyquist stability criterion judge system stability; establish characteristic simulation model; take unit ampere turn value as example result analyzed. The results showed that secondary side fast tracked primary...

The power density of electrical machine is crucial for aircraft applications and the slot/pole number combinations have an essential effect. In this paper, various Halbach surface-mounted permanent magnet machines with different are evaluated. Based on sensitivity analysis global optimization, optimized rated 150 kW at speed 12000 r/min comprehensively compared, particular refence to their density, efficiency, mass, cost. As a result, basic rule in high concluded, reference guideline...

This article firstly models high-frequency and low-frequency signals based on their different characteristics, then proposes a model an estimation method for predicting the capacitive shaft voltage of electric vehicle drive systems without power supply. Then, model, influence two mainstream transmissions is further considered, equivalent circuit transmission established, which can obtain motor shaft, realize modeling calculation overall system vehicles. Finally, paper compares simulation...

A novel method was proposed to improve hydrogen sensitive performance of fiber Bragg grating (FBG) sensor. The the sensor can be greatly improved by using WO3-Pd2Pt-Pt composite films as sensing element. high reflective gratings written in single mode fiber. end-face deposited with WO3-Pd 2 Pt-Pt peak intensity FBG is employed for reference, while that baseline reflected light source used characterization. experimental results prove resolution system reach 5 ppm, and displays good...