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Article
Publication date: 21 March 2016

Yue Ji, Xingfei Li, Tengfei Wu and Cheng Chen

Magnetohydrodynamics angular regular sensor (MHD ARS) has been used in many applications for its low noise in wide bandwidth, impact resistance and low power consumption; however…

Abstract

Purpose

Magnetohydrodynamics angular regular sensor (MHD ARS) has been used in many applications for its low noise in wide bandwidth, impact resistance and low power consumption; however, it is unable to estimate the angular velocity at low frequencies such as below 1 Hz. It is difficult to design compensation methods without an exact model. The aim of this study is to investigate a more exact analytical model characterization of the sensor’s frequency response, especially at a low-frequency zone.

Design/methodology/approach

A correction coefficient of electromagnetic force in simplified MHD ARS model was introduced according to the theoretical analysis of MHD flow and it was obtained by numerical simulation of electromagnetic force varying with time, space structure and frequency.

Findings

To make comparison, the transfer function of the designed MHD ARS in the experiment was identified using Gauss–Newton method with reasonable weights. The identification results confirmed the analytical model. Furthermore, a digital filter was designed based on the analytical model, and the compensation results showed that the frequency limit at low-frequency side was extended from 1 to 0.01 Hz.

Originality/value

The modified analytical model can describe the MHD ARS’s frequency response exactly and may be applied in its low-frequency compensation.

Article
Publication date: 3 September 2019

Hamed Aminzadeh

Multistage amplifiers require a reliable frequency compensation solution to remain stable in a closed-loop configuration. A frequency compensation scheme creates an inner negative…

Abstract

Purpose

Multistage amplifiers require a reliable frequency compensation solution to remain stable in a closed-loop configuration. A frequency compensation scheme creates an inner negative feedback loop amongst different amplifying stages and shapes the frequency response such that an unconditionally stable single-pole amplifier results for closed-loop operation. The frequency compensation loop is thus responsible for the placement of the poles and zeros and the final stability of multistage amplifiers. An amplifier incorporating a sophisticated frequency compensation network cannot be, however, analyzed in the presence of a complex ac feedback loop. The purpose of this study is to provide a reliable model for the compensation loop of multistage amplifiers at the higher frequencies.

Design/methodology/approach

In this paper, the major part of the amplifier, including a two-port network comprising the compensation network, is characterized using a reliable feedback model.

Findings

The model integrates all the frequency-dependent components of the frequency compensation network, and it can evaluate the nondominant real or complex poles of an amplifier.

Originality/value

The reliability of the proposed model is verified through analysis of the frequency response of the amplifiers and by comparing the analytic results with the simulation results in standard CMOS process.

Details

Circuit World, vol. 45 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 10 January 2024

Tingwei Gu, Shengjun Yuan, Lin Gu, Xiaodong Sun, Yanping Zeng and Lu Wang

This paper aims to propose an effective dynamic calibration and compensation method to solve the problem that the statically calibrated force sensor would produce large dynamic…

Abstract

Purpose

This paper aims to propose an effective dynamic calibration and compensation method to solve the problem that the statically calibrated force sensor would produce large dynamic errors when measuring dynamic signals.

Design/methodology/approach

The dynamic characteristics of the force sensor are analyzed by modal analysis and negative step dynamic force calibration test, and the dynamic mathematical model of the force sensor is identified based on a generalized least squares method with a special whitening filter. Then, a compensation unit is constructed to compensate the dynamic characteristics of the force measurement system, and the compensation effect is verified based on the step and knock excitation signals.

Findings

The dynamic characteristics of the force sensor obtained by modal analysis and dynamic calibration test are consistent, and the time and frequency domain characteristics of the identified dynamic mathematical model agree well with the actual measurement results. After dynamic compensation, the dynamic characteristics of the force sensor in the frequency domain are obviously improved, and the effective operating frequency band is widened from 500 Hz to 1,560 Hz. In addition, in the time domain, the rise time of the step response signal is reduced from 0.29 ms to 0.17 ms, and the overshoot decreases from 26.6% to 9.8%.

Originality/value

An effective dynamic calibration and compensation method is proposed in this paper, which can be used to improve the dynamic performance of the strain-gauge-type force sensor and reduce the dynamic measurement error of the force measurement system.

Details

Sensor Review, vol. 44 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 3 July 2017

Vladimir Kindl, Michal Frivaldsky, Pavol Spanik, Marek Piri and Viliam Jaros

This paper aims to develop mathematical models of variously compensated wireless energy transfer (WET) systems. Attention is primarily paid to the derivation of the most important…

Abstract

Purpose

This paper aims to develop mathematical models of variously compensated wireless energy transfer (WET) systems. Attention is primarily paid to the derivation of the most important energy transfer characteristics such as efficiency and amount of transferred power. This paper discusses the main advantages and disadvantages of various compensation techniques to show their possible application areas. On the basis of these results, a designer will be able to quickly identify which compensation type suites as the best solution to fulfill a given system’s requirements.

Design/methodology/approach

First, the current state in the field of mathematical modeling of WET systems is introduced. Next, the non-resonant magnetic-coupled circuit together with four most common resonant magnetic-coupled circuits is analyzed. The equivalent circuit models using loop currents methodology is applied to the analyses. The proposed methodology is experimentally verified by the laboratory measurement of selected circuit topology. The main contribution of the proposed methodology lies in its quick applicability on more complicated or extended systems while keeping a relatively good match with the real system’s behavior.

Findings

The authors have presented the usage of a simple and accurate methodology for investigating variously compensated WET systems. Electrical engineers who require effective and powerful tools for the identification of basic WET systems properties will find this methodology to be of extensive help.

Research limitations/implications

The analyses consider only the sinusoidal type of supply voltage; so, it is valid mainly for the close range of the resonant state. Nonlinearities cannot be taken into account.

Practical implications

This research may be applied in the field of WET systems.

Originality/value

Research in the area of power electronic systems, which provides a clear and straightforward procedure for WET system identification, will be helpful to most practical technicians who are not well versed in areas of physical-based phenomena.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 15 September 2022

Parul Trivedi and B.B. Tiwari

The primary aim of this paper is to present a novel design approach for a ring voltage-controlled oscillator (VCO) suitable for L-band applications, whose oscillation frequency is…

Abstract

Purpose

The primary aim of this paper is to present a novel design approach for a ring voltage-controlled oscillator (VCO) suitable for L-band applications, whose oscillation frequency is less sensitive to power supply variations. In a few decades, with the advancement of modern wireless communication equipment, there has been an increasing demand for low-power and robust communication systems for longer battery life. A sudden drop in power significantly affects the performance of the VCO. Supply insensitive circuit design is the backbone of uninterrupted VCO performance. Because of their important roles in a variety of applications, VCOs and phase locked loops (PLLs) have been the subject of significant research for decades. For a few decades, the VCO has been one of the major components used to provide a local frequency signal to the PLL.

Design/methodology/approach

First, this paper chose to present recent developments on implemented techniques of ring VCO design for various applications. A complementary metal oxide semiconductor (CMOS)-based supply compensation technique is presented, which aims to reduce the change in oscillation frequency with the supply. The proposed circuit is designed and simulated on Cadence Virtuoso in 0.18 µm CMOS process under 1.8 V power supply. Active differential configuration with a cross-coupled NMOS structure is designed, which eliminates losses and negates supply noise. The proposed VCO is designed for excellent performance in many areas, including the L-band microwave frequency range, supply sensitivity, occupied area, power consumption and phase noise.

Findings

This work provides the complete design aspect of a novel ring VCO design for the L-band frequency range, low phase noise, low occupied area and low power applications. The maximum value of the supply sensitivity for the proposed ring VCO is 1.31, which is achieved by changing the VDD by ±0.5%. A tuning frequency range of 1.47–1.81 GHz is achieved, which falls within the L-band frequency range. This frequency range is achieved by varying the control voltage from 0.0 to 0.8 V, which shows that the proposed ring VCO is also suitable for low voltage regions. The total power consumed by the proposed ring VCO is 14.70 mW, a remarkably low value using this large transistor count. The achievable value of phase noise is −88.76 dBc/Hz @ 1 MHz offset frequency, which is a relatively small value. The performance of the proposed ring VCO is also evaluated by the figure of merit, achieving −163.13 dBc/Hz, which assures the specificity of the proposed design. The process and temperature variation simulations also validate the proposed design. The proposed oscillator occupied an extremely small area of only 0.00019 mm2 compared to contemporary designs.

Originality/value

The proposed CMOS-based supply compensation method is a unique design with the size and other parameters of the components used. All the data and results obtained show its originality in comparison with other designs. The obtained results are preserved to the fullest extent.

Details

Circuit World, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 11 February 2021

Yongxing Guo, Min Chen, Li Xiong, Xinglin Zhou and Cong Li

The purpose of this study is to present the state of the art for fiber Bragg grating (FBG) acceleration sensing technologies from two aspects: the principle of the measurement…

Abstract

Purpose

The purpose of this study is to present the state of the art for fiber Bragg grating (FBG) acceleration sensing technologies from two aspects: the principle of the measurement dimension and the principle of the sensing configuration. Some commercial sensors have also been introduced and future work in this field has also been discussed. This paper could provide an important reference for the research community.

Design/methodology/approach

This review is to present the state of the art for FBG acceleration sensing technologies from two aspects: the principle of the measurement dimension (one-dimension and multi-dimension) and the principle of the sensing configuration (beam type, radial vibration type, axial vibration type and other composite structures).

Findings

The current research on developing FBG acceleration sensors is mainly focused on the sensing method, the construction and design of the elastic structure and the design of a new information detection method. This paper hypothesizes that in the future, the following research trends will be strengthened: common single-mode fiber grating of the low cost and high utilization rate; high sensitivity and strength special fiber grating; multi-core fiber grating for measuring single-parameter multi-dimensional information or multi-parameter information; demodulating equipment of low cost, small volume and high sampling frequency.

Originality/value

The principle of the measurement dimension and principle of the sensing configuration for FBG acceleration sensors have been introduced, which could provide an important reference for the research community.

Details

Sensor Review, vol. 41 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 1 December 2005

Peter Sergeant, Luc Dupré and Jan Melkebeek

To design an optimal active shield for the mitigation of the magnetic stray field around an induction heating device.

Abstract

Purpose

To design an optimal active shield for the mitigation of the magnetic stray field around an induction heating device.

Design/methodology/approach

The active shield consists of several compensation coils in series and generates a counter field opposite to the main field. One extra compensation winding – the “generating compensation winding” (GCW) – is positioned close to the excitation coil and works as the secondary winding of a transformer. The power in this winding is used to drive the other compensation coils (the active shield), which are the load of the transformer. A circuit with passive components is inserted between the GCW and the other compensation coils. The shield is optimal if it achieves a high field reduction, while the energy dissipation is low. By using a genetic algorithm (GA) that minimizes an objective function, the optimization algorithm finds the optimal geometry and the optimal current for the GCW and the other compensation coils. The objective function uses time harmonic and axisymmetric finite element calculations.

Findings

The transformer driven active shield reduces the magnetic field effectively. It is cheap and easy to build, but it works well only for one frequency.

Research limitations/implications

The shield is sensitive to tuning of the passive circuit and to changes in the frequency of the induction heater.

Practical implications

This transformer driven shield is an alternative for the classical active shield with external power supply.

Originality/value

An active shield that does not need an external power supply is a cheap solution for the shielding of magnetic fields.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 24 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 7 July 2020

Xiaolei Jiao, Jinxiu Zhang, Hongchao Zhao and Yong Yan

Bellows-type fluid viscous damper can be used to isolate micro vibration in high-precision satellites. The conventional model cannot describe hydraulic stiffness in the medium…

Abstract

Purpose

Bellows-type fluid viscous damper can be used to isolate micro vibration in high-precision satellites. The conventional model cannot describe hydraulic stiffness in the medium- and high-frequency domain of this damper. A simplified analytical model needs to be established to analyze hydraulic stiffness of the damping element in this damper.

Design/methodology/approach

In this paper, a bellows-type fluid viscous damper is researched, and a simplified model of the damping element in this damper is proposed. Based on this model, the hydraulic stiffness and damping of this damper in the medium- and high-frequency domains are studied, and a comparison is made between the analytical model and a finite element model to verify the analytical model.

Findings

The results show that when silicone oil has low viscosity, a model that considers the influence of the initial segment of the damping orifice is more reasonable. In the low-frequency domain, hydraulic stiffness increases quickly with frequency and remains stable when the frequency increases to a certain value; the stable stiffness can reach 106 N/m, which is much higher than the main stiffness. Excessive dynamic stiffness in the high-frequency domain will cause poor vibration isolation performance. Adding compensation bellows to the end of the original isolator may be an effective solution.

Practical implications

A model of the isolator containing the compensation bellows can be derived based on this analytical model. This research can also be used for dynamic modeling and vibration isolation performance analysis of a vibration isolation platform based on this bellows-type fluid viscous damper.

Originality/value

This paper proposed a simplified model of damping element in bellows-type fluid viscous damper, which can be used to analyze hydraulic stiffness in this damper and it was found that this damper showed stable hydraulic stiffness in the medium- and high-frequency domains.

Details

Engineering Computations, vol. 38 no. 1
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 6 August 2020

Hamed Aminzadeh and Mohammad Mahdi Valinezhad

The purpose of this study is to discuss the effect of hybrid cascode compensation with quality factor (Q-factor) control module for the three-stage amplifiers driving ultra-large…

Abstract

Purpose

The purpose of this study is to discuss the effect of hybrid cascode compensation with quality factor (Q-factor) control module for the three-stage amplifiers driving ultra-large load capacitors. Compared to the present frequency compensation solutions, it extends the amplifier bandwidth by establishing an extra AC feedback pathway besides the primary pathway through the Miller capacitor, increasing the loop gain at the gain–bandwidth product (GBW) frequency by pushing to the higher frequencies the nondominant poles.

Design/methodology/approach

A Q-factor control block is used to improve the damping factor of the compensation loop with no power or area overhead, thereby reducing the frequency peaking and the undesired oscillation in the time response for small load capacitors. The Q-factor control module is realized by a tiny-size on-chip capacitor, and provides an extra feedback loop to feed the damping current back to the input stage. A left-half-plane (LHP) zero is also introduced to further improve the stability.

Findings

A prototype of the proposed amplifier is simulated in 180-nm CMOS with a quiescent current of 24-µA from 1.80-V voltage supply. It achieves a 3.98-MHz gain–bandwidth product for 500-pF load capacitor, while the overall compensation capacitor is limited to 0.5-pF and the DC gain is extended beyond 100-dB.

Originality/value

The proposed amplifier is absolutely stable for the load capacitors ranging between 80-pF and 100-nF.

Details

Circuit World, vol. 47 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 11 January 2024

Yuepeng Zhang, Guangzhong Cao, Linglong Li and Dongfeng Diao

The purpose of this paper is to design a new trajectory error compensation method to improve the trajectory tracking performance and compliance of the knee exoskeleton in…

Abstract

Purpose

The purpose of this paper is to design a new trajectory error compensation method to improve the trajectory tracking performance and compliance of the knee exoskeleton in human–exoskeleton interaction motion.

Design/methodology/approach

A trajectory error compensation method based on admittance-extended Kalman filter (AEKF) error fusion for human–exoskeleton interaction control. The admittance controller is used to calculate the trajectory error adjustment through the feedback human–exoskeleton interaction force, and the actual trajectory error is obtained through the encoder feedback of exoskeleton and the designed trajectory. By using the fusion and prediction characteristics of EKF, the calculated trajectory error adjustment and the actual error are fused to obtain a new trajectory error compensation, which is feedback to the knee exoskeleton controller. This method is designed to be capable of improving the trajectory tracking performance of the knee exoskeleton and enhancing the compliance of knee exoskeleton interaction.

Findings

Six volunteers conducted comparative experiments on four different motion frequencies. The experimental results show that this method can effectively improve the trajectory tracking performance and compliance of the knee exoskeleton in human–exoskeleton interaction.

Originality/value

The AEKF method first uses the data fusion idea to fuse the estimated error with measurement errors, obtaining more accurate trajectory error compensation for the knee exoskeleton motion control. This work provides great benefits for the trajectory tracking performance and compliance of lower limb exoskeletons in human–exoskeleton interaction movements.

Details

Robotic Intelligence and Automation, vol. 44 no. 1
Type: Research Article
ISSN: 2754-6969

Keywords

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