Search

The full-bridge can further improve the output power through parallel inverters. The inverter output voltage of single-switch LC resonant circuit is a combination of trapezoidal wave and half sine wave, there is no relevant research on parallel connection of single-switch LC resonant circuit. Therefore, this paper presents a novel input-parallel single-switch LC resonant circuit, this topology adopts switchable secondary networks for constant-current (CC) and constant-voltage (CV) output, and prevents shoot-through of power switches. The decoupling between transmitters simplifies the analysis and calculation. The input-parallel structure avoids the unbalanced input voltage of each inverter and improves the stability of the WPT system. CC and CV output modes can be achieved by controlling one relay without adding DC-DC converters or changing switching frequency. This paper includes decoupling equivalent analysis of coils, topologies analysis of CC mode and CV mode, calculation of equivalent input AC voltage source, design of magnetic coupler and circuit parameters. Finally, a 1-kW experimental prototype is built to verify the theoretical analysis, the maximum efficiency can reach 92.5%.

In this article, a 10-MHz low-profile converter for bendable equipment based on aircore inductor is proposed. The mathematical model and inductance calculation method of the bendable planar circular spiral coil under different bending situations is analyzed. An optimal design method of the T type matching network is depicted in detail which helps to guarantee soft-switching characteristics and high efficiency within the whole bending range by realizing weak inductive equivalent input impedance. A 32 V input, 9V/6.3 W output prototype is proposed in the laboratory and the experimental results verify the feasibility of the proposed optimal design methodology, the system efficiency can be improved by 4% than the traditional method.

In this paper, an auxiliary-model method is proposed for calculating equivalent input seismic loads in research of ground motions. This method can be used to investigate the local effect of 3D complex sites subjected to obliquely incident SV and P waves. Using this method, we build a fictitious auxiliary model along the normal direction of the boundary of the area of interest, with the model’s localized geological features remaining the same along a vector normal to this boundary. This model is divided into five independent auxiliary models, which are then dynamically analyzed to obtain the equivalent input seismic loads. Unlike traditional methods, in this new technique, the mechanical behavior of the auxiliary model can be nonlinear, and its geometry can be arbitrary. In addition, a detailed description of the steps to calculate the equivalent input seismic loads is given. Numerical examples of incident plane-wave propagation at uniform sites with local features validate the effectiveness of this method. It is also applicable to elastic and non-elastic problems.

for the longitudinal seismic response analysis of a tunnel structure under asynchronous earthquake excitations, a longitudinal integral response deformation method classified as a practical approach is proposed in this paper. The determinations of the structural critical moments when maximal deformations and internal forces in the longitudinal direction occur are deduced as well. When applying the proposed method, the static analysis of the free-field computation model subjected to the least favorable free-field deformation at the tunnel buried depth is performed first to calculate the equivalent input seismic loads. Then, the equivalent input seismic loads are imposed on the integral tunnel-foundation computation model to conduct the static calculation. Afterwards, the critical longitudinal seismic responses of the tunnel are obtained. The applicability of the new method is verified by comparing the seismic responses of a shield tunnel structure in Beijing, determined by the proposed procedure and by a dynamic time-history analysis under a series of obliquely incident out-of-plane and in-plane waves. The results show that the proposed method has a clear concept with high accuracy and simple progress. Meanwhile, this method provides a feasible way to determine the critical moments of the longitudinal seismic responses of a tunnel structure. Therefore, the proposed method can be effectively applied to analyze the seismic response of a long-line underground structure subjected to non-uniform excitations.

Hybrid AC-DC systems integrate ac bus and various dc buses as well as multiple power electronic converters, and such systems are consequently vulnerable to instability issues. In order to investigate the stabilities of hybrid AC-DC systems with multiple dc buses and identify which converters are mainly responsible for instability, this article proposes a stage-by-stage stability analysis method. The small-signal models of AC-DC and DC-DC converters are established, based upon which the whole system is separated into multiple stages according to its structure, and checked stage-by-stage. Make sure that equivalent input admittance (or impedance) of stage $k(k=2, 3, \ldots)$ has no right-half-plane poles so that it is self-stable, then consider the equivalent input admittance (or impedance) of stage $k$ as the equivalent load admittance (or impedance) of stage $k-1$ , and check the stability of stage $k-1$ ; and repeat the process until the whole system has been checked. All stage being stable can ensure the stability of overall system. The converters that are mainly responsible for instability can be clearly identified by this stage-by-stage method, and it could be beneficial for stability enhancement of the system. The effectiveness of the proposed method is verified by simulations in PSCAD/EMTDC and experiments of the control hardware in the loop (CHIL).

Micromachined resonant accelerometers (MRAs) are very attractive for high-precision measurement applications due to their high sensitivity, frequency output, and large dynamic range. The sensitivity is one of critical metrics in MRA sensors. In order to enhance this metric, a micro-lever is usually used. However, the micro-lever may suffer from the attenuation of effective amplification ratio and increasing the structure complexity. Lowering spring stiffness of suspension structure and enlarging the proof mass are alternative methods, but these methods are restricted in real devices due to the trade-offs for the device sizes, cross-axis sensitivity, robustness and fabrication yield. This paper presents a novel method to improve sensitivity of MRAs by using electrostatic spring softening effect without sacrificing the mechanical robustness or enlarging footprint size of the device. Besides, this method can on-line adjust the sensitivity of MRAs, which is another potential advantage for specific applications. The prototype has been designed, fabricated and characterized in both open-loop and close-loop ways. In agreement with the proposed device model, the experiment results demonstrated that the sensitivity of the prototype device increased from 492.7 Hz/ ${g}$ ( ${g}$ being the gravity acceleration) to 2277 Hz/ ${g}$ by using a sensitivity enhancing bias voltage of 67V in a linear scale range of $\pm 1~{g}$ . Moreover, the prototype’s equivalent input acceleration noise reduces down from 5.5 ug / $\surd $ Hz to 1.6 ug / $\surd $ Hz within 1Hz bandwidth, and the bias-instability is down from 6.1 ug to 2.2 ug .

This brief presents a low power low noise amplifier (LNA) in TSMC $0.18~{\mu }\text{m}$ CMOS technology for ultrasound imaging probes. The proposed LNA is based on a trans-impedance amplifier (TIA). Single-ended to differential conversion is realized using a common-gate and a common-source (CG-CS) based structure. Resistive feedback is exploited to provide a noise canceling scheme for the CS transistor. Unlike the conventional CG-CS structure that can only eliminate the noise of the CG transistor, the proposed structure eliminates the noise of both CG and CS transistors as well as the CG stage load resistor. Furthermore, by using negative feedback in the CG stage and current reuse technique in both stages, power consumption is reduced. Post-layout simulation results show a trans-impedance gain of 82 dB ${\Omega }$ with a −3 dB bandwidth of 77 MHz, while input impedance is $731~{\Omega }$ . The second harmonic distortion (HD2) is lower than −48.5 dB and the equivalent input referred noise is $1.95~{pA/\sqrt {Hz}}$ at 5 MHz. The circuit occupies an active area of $312~{\mu m^{2}}$ and consumes 47 $\boldsymbol {\mu }\text{W}$ from a 1.2 V supply.

International audience; Ensemble statistics of a visual scene can be estimated to provide a gist of the scene without detailed analysis of all individual items. The simplest and most widely studied ensemble statistic is mean estimation, which requires averaging an ensemble of elements. Averaging is useful to estimate the mean of an ensemble and discard the variance. The source of variance can be external (i.e., variance across the physical elements) or internal (i.e., imprecisions in the estimates of the elements by the visual system). The equivalent noise paradigm is often used to measure the impact of the internal variance (i.e., the equivalent input noise). This paradigm relies on the assumption that the averaging process is equally effective independently of the main source of variance, internal or external, so any difference between the processing when the main source of variance is internal or external must be assumed not to affect the averaging efficiency. The current fMRI study compared the neural activity when the main variance is caused by the stimulus (i.e., high variance) and when it is caused by imprecisions in the estimates of the elements by the visual system (i.e., low variance). The results showed that the right superior frontal and left middle frontal gyri can be significantly more activated when the variance in the orientation of the Gabors was high than when it was low. Consequently, the use of the equivalent noise paradigm requires the assumption that such additional neural activity in high variance does not affect the averaging efficiency.

This article proposes a double-sided inductor–capacitor–capacitor–capacitor matrix (D-LC-CCM) impedance matching network to eliminate the impact of the load and the mutual inductance variation on inductive power transfer system. A thorough mathematical analysis is conducted and a control strategy is proposed to obtain a constant current output when the load and the mutual inductance vary. When the load changes, the equivalent impedance of the secondary side can be kept unchanged by adjusting the capacitor matrix in the receiver, then adjusting the input voltage can achieve constant current output simultaneously. The equivalent input impedance of the primary side and the output current can remain stable by adjusting the capacitor matrix in the transmitter when the mutual inductance changes. The experimental prototype was built, and the system constant current output was achieved when the load changes from 40 to 80 Ω and the mutual inductance varies from 13 to 17 μ H, which has validated the effectiveness of the D-LC-CCM impedance matching network.

Multitransmitter wireless power transfer system gets more and more applications as it can maintain high efficiency in a large space range. This article focuses on modeling the multitransmitter system, and proposes an impedance matching method to improve efficiency under lateral-misalignment conditions. The theoretical analysis shows that the maximum transfer efficiency can be achieved as long as the equivalent input impedance of the transmitters is regulated to be the same under misalignment condition. Hence, a double closed-loop control strategy is proposed to realize maximum efficiency point tracking, where the primary control loop adjusts the input impedance of the transmitters through pulsewidth modulation, while the second control loop maintains constant output power by a dc–dc converter. A 500-W prototype is built to validate the feasibility of the proposed method. The efficiency is always higher than 90% with an improvement of up to 20.3% compared to that without such a method when the lateral misalignment increases from 0 to 10 cm (0%–41% of maximum coil size).

This paper proposes a clock strategy to improve the precision of power-efficient readout circuit for capacitive sensor. To achieve high power efficiency, capacitive sensor such as MEMS accelerometer is designed with open-loop architecture rather than close-loop one. In the open-loop architecture, the capacitance variation of sensing element is limited to femto-farad level in order to overcome nonlinearity problem. However, due to this limitation, the signal charge from sensing element is weak and the interference charge due to coupling capacitance between clock wires and sensing electrodes becomes a significant issue. Therefore, split clock bus is employed to meet this challenge, but the split clock bus introduces the timing mismatch which causes the charge injection sensitive to fabrication process and circuit operating voltage. As a result, the input offset, the variation of the offset and the nonlinearity of readout circuit will increase, and this will lead to reduction of precision. In this work, a clock scheme named “multi-nested clocks” is proposed to address the charge injection problem. The multi-nested clocks are demonstrated in a readout circuit fabricated using a $0.18-\mu \text{m}$ BCD process. The measurement results show that compared to the readout circuit using traditional clock, the readout circuit using the multi-nested clocks significantly reduces the equivalent input offset from 1.66fF to 0.25fF, the offset variation from 1.4fF to 0.2fF and the nonlinearity from 5.5% to 0.9%.

An in situ colored dissolved organic matter sensor based on a frequency spectrum shifted maximum-length sequence (FSSM) modulation method was proposed in this paper. The energy behavior resulting from the direct maximum-length sequence (m-sequence) modulation method was analyzed. We found a kind of twice modulation method, which optimizes m-sequence frequency spectrum structures. This novel method can effectively reduce the energy loss caused by filtering and reduce the noise introduced by demodulation. The sensitivity of the developed sensor was improved to an unprecedented level by optimizing the modulation/demodulation scheme without increasing the light-emitting diode intensity. Subsequently, we developed a cost-saving hardware sensor which can meet the requirements of the in situ measuring system with the FSSM modulation method. The equivalent input noise current of the electronic system can be as low as 12.20 fA. The limit of detection (LOD) of the sensor reached a maximum of $0.0168 \mu \text {g/L}$ within a concentration range of 0– $3000~\mu \mathrm {g/L}$ , and with an R-squared value of 0.9967. The results demonstrated that the LOD of our sensors was fivefold higher than the LOD of commercially available chromophoric dissolved organic matter (CDOM) sensors and doubled its normal detection range. The sensor also exhibited excellent anti-interference ability and it can attenuate sunlight and electromagnetic interference by up to ten times while improving the stability of the system. The improvement of the CDOM sensor’s performance is of great significance to the marine environmental information monitoring field.

A methodology for designing ternary circuits is proposed and evaluated. The method is based on a schema that consists of voltage levels, conditional blocks and weighting elements. The main idea is selecting appropriate voltage levels in conditional blocks and weighting them to generate desired output. In fact, the diagram is a framework for designing ternary logic gates. Hence, the optimum design can be accomplished by choosing the proper strategy particularly in conditional blocks. This could lead to minimum count of elements and decrement in complexity of the circuit. To examine the efficiency of the proposed method, three designs for standard ternary inverter (STI), ternary NAND (TNAND) and ternary NOR (TNOR) gates in carbon nanotube field-effect-transistor (CNFET) technology are presented, respectively. Several simulations are done using Synopsys HSPICE tool in 32 nm CNFET technology to measure the performance parameters for proposed designs and state-of-the-art CNFET-based designs. Moreover, the robustness of STIs in different operational conditions such as variations frequency and output load, and their senility to process deviations are measured. The simulation is done for TNAND, TNOR and half adder cell as well. The results demonstrate the proper functionality of the proposed methodology. Moreover, the designed circuits benefit from the minimum count of CNFETs, least maximum equivalent input capacitor, minimum variety of CNT diameters and delay time, while its pdp is very close to best results in comparison with state-of-the-art designs.

MMI like power coupler using nano-pixel exhibits unique “equivalent” input of, not only intensity, phase. The simulated results show equivalent input (intensity and phase) coupling capability, with 1/500 times compact foot-print.

The method of inputting the seismic wave determines the accuracy of the simulation of soil-structure dynamic interaction. The wave method is a commonly used approach for seismic wave input, which converts the incident wave into equivalent loads on the cutoff boundaries. The wave method has high precision, but the implementation is complicated, especially for three-dimensional models. By deducing another form of equivalent input seismic loads in the finite element model, a new seismic wave input method is proposed. In the new method, by imposing the displacements of the free wave field on the nodes of the substructure composed of elements that contain artificial boundaries, the equivalent input seismic loads are obtained through dynamic analysis of the substructure. Subsequently, the equivalent input seismic loads are imposed on the artificial boundary nodes to complete the seismic wave input and perform seismic analysis of the soil-structure dynamic interaction model. Compared with the wave method, the new method is simplified by avoiding the complex processes of calculating the equivalent input seismic loads. The validity of the new method is verified by the dynamic analysis numerical examples of the homogeneous and layered half space under vertical and oblique incident seismic waves.

This paper presents both an observer/Kalman filter identification (OKID) method-based linear quadratic digital tracker (LQDT) and a new functional observer-based discrete equivalent input disturban...

A design method of line commutated converter (LCC) compensation network for the dynamic wireless power transfer (DWPT) system based on a complex impedance model (Z-model) of the input impedance of the rectifier is proposed in this study. The continuous conduction mode and discontinuous conduction mode (DCM) of the rectifier are analysed to calculate the equivalent input impedance of the rectifier. Based on the proposed model of the input impedance of the rectifier, a design method of LCC compensation network for the DWPT system is presented. Simulation results prove that the Z-model of the rectifier is more accurate than the prevailing resistive model. Experiments show that the DWPT system with the designed LCC network meets the requirement of the average output power with an average DC–DC efficiency over 93%.

Magnetoelectric (ME) gyrators are unique circuit elements capable of direct conversion of the current to voltage or vice versa. In order to understand the power conversion and loss processes in the gyrators, an equivalent input loss factor has been developed in this paper based on Mason's model (equivalent circuit model). This factor serves to understand the loss transferring mechanism and to evaluate the conversion efficiency for the electric power in ME gyrators. Studies have been carried out for modeling the power conversion in both the solenoid and the ME core. Several important factors have been proposed and discussed to enhance the conversion efficiencies in the electric–magnetic–mechanical three-phase conversion process. A simplification of our equations reveals that the efficiency of the ME gyrator is related to the product of the effective coupling ( k2 $_{\text{eff, m}}$ ) and mechanical quality ( Q mech). According to our model, magnetic and electric materials with high k $_{\text{eff, m}}$ and Q mech values are the key ingredients to enhance the efficiency of ME gyrators. We have successfully realized a power efficiency of 92% based on a Metglas/hard-PZT ME gyrator, which showed a good correlation to the predicted values.

Totally implantable hearing devices have been proposed as a solution to mitigate limitations associated with external elements in traditional hearing devices. However, requirements for an implantable sensor are difficult to be achieved concurrently, and therefore, no sensor developed fulfills them entirely. In this paper, we investigate how various geometries of MEMS piezoelectric accelerometers, optimized via different optimization techniques, behave in terms of the equivalent input noise (EIN) in sound pressure level (SPL) when coupled to the middle ear ossicular chain. An alternative optimization goal based on the minimization of the EIN is proposed in contrast to the traditional charge sensitivity maximization, and this alteration rendered near 20-dB improvement in EIN in low frequencies. Prototypes are fabricated through a multi-user batch process featuring a 500-nm aluminum nitride piezoelectric layer and experimentally characterized for the validation of the finite-element analysis and analytic modeling of spectral noise. Despite limitations imposed by the current batch fabrication process, we are able to design a highly competitive implantable sensor in the form of a $2\times 2\,\,\textrm {mm}^{2}$ footprint cantilever accelerometer, which should be able to detect 60-dB SPL between 250 Hz and 8 kHz. These promising results establish piezoelectric sensors as a viable alternative for totally implantable hearing devices and put an implantable sensor, which fulfills all requirements concurrently within our grasp.

SRM is nonlinear system. This study discusses the SRM speed control as the main driving force for electric vehicles using linear approach. The SRM used in this paper has a narrow input saturation range. SRM only rotates at the PWM value of 72-84 or the equivalent input voltage to the SRM driver of 1.446 volts - 1.753 volts. At the PWM value of 0-71 and PWM 85-255, the SRM does not rotate (dead zone). This study discusses the design of SRM speed control with PI and PI Antiwindup (PI AW) methods in that narrow input saturation range. The design is done by modelling the system in the SysId MATLAB by looking at the SRM response when PWM input is given. A first-order dynamic model is obtained from the identification results with the SysId MATLAB. The controller design is carried out analytically. At the implementation stage, the control signal used is only a positive control signal that makes the motor rotate without any braking effect. The results of the implementation of PI and PI AW are compared to see the performance of the two controllers. From the simulation and implementation, data is obtained that the designed control system can control the SRM speed in reaching the steady state value, the overshoot value and the steady state error leading to 0%. PI AW controller has better performance than PI controllers in terms of settling time and overshoot percentage. The PI controller has a slight advantage at steady state error over the PI AW controller.

DC microgrids have become a prevalent topic in research in part due to the expected superior efficiency of DC/DC converters compared to their AC/DC counterparts. Although numerous side-by-side analyses have quantified the efficiency benefits of DC power distribution, these studies all modeled converter loss based on product data that varied in component quality and operating voltage. To establish a fair efficiency comparison, this work derives a formulaic loss model of a DC/DC and an AC/DC PFC boost converter. These converters are modeled with identical components and an equivalent input and output voltage. Simulated designs with real components show AC/DC boost converters between 100 W to 500 W having up to 2.5 times more loss than DC/DC boost converters. Although boost converters represent a fraction of electronics in buildings, these loss models can eventually work toward establishing a comprehensive model-based full-building analysis.

The Holos-Quad micro-reactor concept is proposed by HolosGen LLC for civilian applications to generate 22 MWt with a lifetime of approximately 8 effective full power years (EFPYs). The design is based on a very innovative high-temperature gas-cooled reactor concept using four Subcritical Power Modules (SPMs) that fit into one commercial 40-foot transport ISO container. Neutronics benchmarks were developed based on a preliminary version of the Holos-Quad design to confirm feasibility of the neutronics design of this non-traditional high temperature gas-cooled (HTGR)-type micro-reactor concept. Calculations were performed using Monte Carlo codes (SERPENT and OpenMC) as well as the PROTEUS high-fidelity deterministic code for two exercises based on a unit cell model and a full core model. The results obtained showed good agreement with all of the evaluated parameters for the unit cell problem and the full core problem. SERPENT and OpenMC display consistently good agreement in eigenvalue within 150 pcm for the unit cell benchmark and less than 270 pcm for the full core benchmark. PROTEUS eigenvalues showed relatively larger differences but still reasonable agreement with the SERPENT solutions. For the depletion benchmark, the observed eigenvalue differences between SERPENT and OpenMC were within 300 pcm throughout the depletion up to 100 GWd/MT, ensuring that the two codes used equivalent input parameters such as the recoverable heat values for fission reactions. This benchmark exercise confirms the neutronic feasibility and core performance of the preliminary Holos-Quad design.

The paper presents a system for noise measurements in infrared photodetectors characterized by low shunt resistances based on a two-channel ultra-low-noise voltage amplifier with paralleled discrete JFETs at the input stages. Using cross correlation method, a background noise well below of 10−19 V2/Hz can be obtained at frequencies above 10 Hz. To facilitate the estimation of the noise in such a wide frequency range (5 decades), we also developed a software based on the QLSA library. As a result of these efforts, the equivalent input voltage noise of the system is below 10−19 V2/Hz at 10 Hz and 10−20 V2/Hz for frequencies above a few hundred Hz. The system effectiveness is demonstrated by noise measurements at room temperature on advanced InAsxSb1-x photodetectors characterized by an active area of 1 mm2 and a shunt resistance below 10 Ω.

A source-follower (SF) based differential input buffer for high speed ADCs, in which an auxiliary SF pair and a current amplifier pairs generate a differential compensation current injecting into the main SF pair to achieve linearization is presented. Designed in a 28nm CMOS, the two tone simulation (1.4-Vpp input at 5.92GHz and 5.98GHz) result with 6-GSPS sampling frequency, and 2.5-V VDD supply voltage shows that the buffer achieves an SFDR of 76.3dBFS, equivalent input noise about 200uV and offet 1mV at most while consumes only 150-mW power(Differential pair). Compared to the conventional structure, the proposed input buffer is more suitable for low-power and low-voltage applications, and brings smaller capacitive load to the input source.

In this paper, the design method of matching network in a 10MHz DC / DC converter based on flexible aircore inductor is proposed. The mathematical model and inductance calculation method of flexible planar circular spiral coil under different bending situations is analyzed. The design method of T-matching and π-matching networks under variable inductance are depicted in detail to ensure resistive or weak inductive equivalent input impedance of the matching network, which helps to guarantee soft-switching characteristics and high efficiency within a wide bending range. A 32V input, 9V/6.3W output prototype is proposed in the laboratory and the experimental results verify the feasibility of the proposed optimal design methodology.

A low noise precision operational amplifier is presented in this paper, which has the advantages of low offset and low noise for high precision, high resolution and low error applications. The design was fabricated with a 40V bipolar process. The input stage of the circuit is a resistive load differential pair with an input bias current compensation structure. The second stage is a common-emitter structure in the middle. The output stage is complementary push-pull structure. When power supply is ±15V, measured results show that slew rate of the OPA is 0.3V/μs, it gets an open loop gain of 132dB with a supply current of 1.7mA and an input bias current of 2nA, the equivalent input noise is only 8nV/ √ Hz, and the area is about 2.3mm×1.6mm.

In this paper, we derive new models that describe the noise voltage and equivalent input noise current spectral densities for multiplicative distributed amplifiers. Based on the derived models, design optimisation techniques to minimise the noise contribution of transimpedance amplifiers based on the multiplicative DA topologies are proposed.

Bridge crane system is widely used in production and life. Even so, we still have a lot of problems to solve on it, such as trajectory planning for the large vehicle and small vehicle and anti-swing of the hoist. However, the anti-swing problem of the bridge crane system is an issue of great value. A sliding mode control method is designed to solve this problem. Because of the characteristic that the bridge crane system is an under-actuated system, it is modeled on Lagrangian dynamics. The effect of the ordinary sliding mode control method for under-actuated systems is no longer satisfactory. A hierarchical sliding mode control is used instead of the ordinary sliding mode control. For under-actuated systems, the basic idea of the hierarchical sliding mode control method is to separate the driving part and under-acting part of the system into different subsystems. In this control method, the slip surface is divided into two layers. The first layer of slip surface includes two parts: one is the displacement error sub-sliding surface of vehicle, and the other is the suspended swing error sub-sliding surface. The second layer is the total slip surface. It contains two sub-sliding surfaces in the direction of the vehicle. The equivalent input term in the sense of Filippov is obtained according to the sliding mode surface of the first layer, and the switching control function term is obtained from the sliding mode surface of the second layer using the Lyapunov feedback function design method. The total system input can be got by combining the equivalent input term and the switching control function term. The simulation experiment by using the simulation module of Matlab is operated, and the simulation results prove the method has good control effect and robustness.

Innovation is the core driving force of high-end equipment manufacturing industry, and the evaluation of its efficiency has important theoretical and practical value. In this paper, taking Guangdong Province as an example, which is a strong province of high-end equipment manufacturing industry in China. DEA Malmquist index method is utilized. Different from other DEA methods, this method is used to study the variation of efficiency, instead of just giving the efficiency value. In order to reduce the repeatability of the existing index system and ensure the scientificity and accuracy of the evaluation results, two new input index parameters, namely, full-time equivalent input of R&D personnel and internal expenditure of R&D funds, were constructed innovatively. The results show that in order to improve the technological innovation efficiency of high-end intelligent manufacturing in Guangdong province, it is not enough to focus on innovation itself, but also to focus on the transformation of innovation achievements.

Purpose Recent evidence shows that macular damage is common even in early stages of glaucoma. Here we investigated whether contrast sensitivity loss in the central vision of glaucoma patients is due to an increase in equivalent input noise (Neq), a decrease in calculation efficiency, or both. We also examined how retinal undersampling resulting from loss of retinal ganglion cells (RGCs) may affect Neq and calculation efficiency. Methods This study included 21 glaucoma patients and 23 age-matched normally sighted individuals. Threshold contrast for orientation discrimination was measured with a sinewave grating embedded in varying levels of external noise. Data were fitted to the linear amplifier model (LAM) to factor contrast sensitivity into Neq and calculation efficiency. We also correlated macular RGC counts estimated from structural (spectral-domain optical coherence tomography) and functional (standard automated perimetry Swedish interactive thresholding algorithm 10-2) data with either Neq or efficiency. Furthermore, using analytical and computer simulation approach, the relative effect of retinal undersampling on Neq and efficiency was evaluated by adding the RGC sampling module into the LAM. Results Compared with normal controls, glaucoma patients exhibited a significantly larger Neq without significant difference in efficiency. Neq was significantly correlated with Pelli-Robson contrast sensitivity and macular RGC counts. The results from analytical derivation and model simulation further demonstrated that Neq can be expressed as a function of internal noise and retinal sampling. Conclusions Our results showed that equivalent input noise is significantly elevated in glaucomatous vision, thereby impairing foveal contrast sensitivity. Our findings further elucidated how undersampling at the retinal level may increase equivalent input noise.

The galvanic-coupled human body communication (HBC) has come out as an alternative to radio frequency communication for connecting miniaturized wearable, implantable devices in, on the human body. The existed researches focused on the channel characteristics measurement, less on transceiver. The analog front-end (AFE) circuit is the significant part of the transceiver. In this paper, a wearable AFE circuit for human body communication is proposed, which can be utilized for subsequent signal recovery or demodulation. Differential input and filter hold circuits are used to get rid of interference from the environment and the human body. The variable gain amplifier module is applied as the final stage amplifier to reduce the influence of the change caused by the contact instability of the output electrodes. The performance index of the front-end circuit is obtained by analyzing the experimental results. The results show that the circuit has a high gain flatness. When the circuit gain is 40 dB, the gain error is within ± 0.5 dB in the frequency range of 10kHz-1MHz. The common-mode rejection ratio of the circuit can reach 112 dB, and the voltage equivalent input noise is only 3 nV/√Hz, which can guarantee the stability of HBC in complex situations. In the end, the effectiveness of the analog front-end circuit is verified by in vivo experiments.

Compared with the traditional plug-in charging system, the wireless charging system for battery charging has broad application prospects due to its significant advantages, such as security, convenience, and aesthetics. In practical applications, in order to prolong the battery lifecycles, it is preferred to charge the battery with constant current (CC) and constant voltage (CV) modes. However, since the battery equivalent resistance varies greatly during charging, it is not easy to design a complete charging system owning CC and CV output characteristics. Besides, the equivalent input impedance of the system is preferably resistive to improve efficiency and enhance power transfer capability; therefore, achieving the zero phase angle (ZPA) operation is extremely important. Hence, a novel three-coil structure WPT system is proposed in this paper to solve the above issues. A comprehensive theoretical analysis for the three-coil system to realize the CC and CV charging modes with perfect ZPA operation at two fixed operating frequencies is presented. Furthermore, due to the parasitic losses of passive components and the instability of the dc input voltage, it is unrealistic to achieve accurate and stable CC and CV outputs through the inherent properties of the circuit itself. Consequently, a simple closed-loop controller is introduced into the system to enable the desired CC and CV charging characteristics with zero voltage switching (ZVS) operation by slightly adjusting the operating frequency. Finally, a confirmatory experimental prototype with 4.6-A charging current and 56-V charging voltage is fabricated to confirm the feasibility and validity of the proposed method. The experimental results agree well with the theoretical analysis.

In this paper, we present a monolithic microsystem, which can perform bioimpedance analysis and electroimpedance tomography measurements as well as record electrocardiogram signals. In contrast to a full analog lock-in approach, a mixed analog/digital solution is adopted. The proposed solution has been designed, implemented, and tested using a commercial 0.35-μm CMOS technology. The tuning range of the signal generator and the detector is from 10 kHz to 10 MHz in 1 kHz steps. The circuit ensures a CMRR of 81 dB@10 kHz, which increases to 84 dB@10 MHz. The measured equivalent input noise power spectral density is en = 2.57 nV/√Hz at 10 kHz in the worst case, close to the 1/f corner frequency. It decreases until en = 1.8 nV/√Hz at 1 MHz and en = 1.9 nV/√Hz at 10 MHz. Measurements of a reference RC network performed with the proposed monolithic solution and compared with a Keysight E4980A Precision LCR Meter shows a maximal relative error of 0.8% over the whole operating frequency range.

An active disturbance rejection control (ADRC) based on equivalent input disturbances (EID) for load frequency control (LFC) is proposed for power system with communication delays. This method can eliminate the influence of parameter uncertainty and load variation, and ensure high dynamic performance by compensation of EID. The proposed method can effectively compensate kinds of disturbance, neither need the characteristic information of the disturbance nor need the inverse model of the plant. The state of the controlled object is reconstructed by the improved state observer, and then the state space model of the close-loop time delay power system is established. The system stability conditions are given in the form of LMI and the parameters of the controller are obtained. Finally, simulation results show the proposed method is significant to maintain system stability and validate its robustness and effectiveness.

This paper presents an impedance-based method to systematically investigate the interaction between multi-train and traction networks, focusing on evaluating the harmonic instability problems. Firstly, the interaction mechanism of multi-train and the traction network is represented as a feedback interconnection of the two subsystems, i.e., an equivalent output impedance of the traction network and an equivalent input admittance of the multi-train. Then the harmonic instability is evaluated through a series of pole-zero diagrams drawn from the closed loop transfer matrix of the multi-train and traction network interaction system. The interaction system is unstable and the harmonic instability will happen if there are some high frequency poles of the closed loop system located in the right half plane. This method is used for analyzing the harmonic instability phenomena and its characteristics, its factors and also possible mitigation schemes. The theoretical results are further validated by the simulations and experiments.

This paper presents the analysis of a rectifier load used for an electric vehicle (EV) wireless charging system, as well as its applications on compensation network design and system load estimation. First, a rectifier load model is established to get its equivalent input impedance, which contains both resistance and inductance components, and can be independently calculated through the parameters of the rectifier circuit. Then, a compensation network design method is proposed, based on the rectifier load analysis. Furthermore, a secondary side load estimation method and a primary side load estimation method are put forward, which adopt only measured voltages and consider the influence of the rectifier load. Finally, an EV wireless charging prototype is developed, and experimental results prove that the rectifier equivalent load can be correctly calculated on conditions of different system load resistances, rectifier input inductances, dc voltages, and mutual-inductances. The experiments also show that rectifier load equivalent inductance will impact system performances, and the proposed methods have good accuracy and robustness in the cases of system parameter variations.

This paper presents new operational floating current conveyor (OFCC) based Programmable Gain Amplifier (PGA). It operates in trans-impedance mode i.e. it receives current signal as input and provides voltage as output. It uses four blocks – a current amplifier, digitally controlled trans-impedance amplifier, digitally controlled R-2R ladder network and a voltage buffer. First block amplifies input signal. Second and third blocks of proposed PGA provide control over coarse and fine gain through bits (B5–B0) and a total of 60 different gain values are possible through the arrangement. The last block provides output at low impedance thereby avoiding need of impedance matching circuit. The operation of the proposal has been verified through SPICE simulations using 0.5 µm technology model parameters from MOSIS (AGILENT). The simulated variable gain range is found to be 56.76 dBΩ to 95.84 dBΩ. The total power dissipation is 3.13 mW under maximum gain settings. The equivalent input referred noise is found to be 6.9 pA/√Hz. Experimental verification of proposed PGA is also done by bread boarding the entire circuit. The measured results are found to be in close agreement with the theoretical and simulated values.

Este trabajo fue parcialmente financiado por CSIC (Comisión Sectorial de Investigación Científica, Uruguay), ANII (Agencia Nacional de Investigación e Innovación, Uruguay) y CAP (Comisión Académica de Posgrado, Uruguay). There are neural recording applications in which the amplitude of common-mode interfering signals is several orders of magnitude higher than the amplitude of the signals of interest. This challenging situation for neural amplifiers occurs, among other applications, in neural recordings of weakly electric fish or nerve activity recordings made with cuff electrodes. This paper reports an integrated neural amplifier architecture targeting invivo recording of local field potentials and unitary signals from the brain stem of a weakly electric fish Gymnotus omarorum. The proposed architecture offers low noise, high common-mode rejection ratio (CMRR), current-efficiency, and a high-pass frequency fixed without MOS pseudoresistors. The main contributions of this work are the overall architecture coupled with an efficient and simple single-stage circuit for the amplifier main transconductor, and the ability of the amplifier to acquire biopotential signals from high-amplitude common-mode interference in an unshielded environment. A fully-integrated neural preamplifier, which performs well in line with the state-of-the-art of the field while providing enhanced CMRR performance, was fabricated in a 0.5 μm CMOS process. Results from measurements show that the gain is 49.5 dB, the bandwidth ranges from 13 Hz to 9.8 kHz, the equivalent input noise is 1.88 μVrms, the CMRR is 87 dB and the Noise Efficiency Factor is 2.1. In addition, in-vivo recordings of weakly electric fish neural activity performed by the proposed amplifier are introduced and favorably compared with those of a commercial laboratory instrumentation system.

The other-race effect is the finding of diminished performance in recognition of other-race faces compared to those of own-race. It has been suggested that the other-race effect stems from specialized expert processes being tuned exclusively to own-race faces. In the present study, we measured recognition contrast thresholds for own- and other-race faces as well as houses for Caucasian observers. We have factored face recognition performance into two invariant aspects of visual function: efficiency, which is related to neural computations and processing demanded by the task, and equivalent input noise, related to signal degradation within the visual system. We hypothesized that if expert processes are available only to own-race faces, this should translate into substantially greater recognition efficiencies for own-race compared to other-race faces. Instead, we found similar recognition efficiencies for both own- and other-race faces. The other-race effect manifested as increased equivalent input noise. These results argue against qualitatively distinct perceptual processes. Instead they suggest that for Caucasian observers, similar neural computations underlie recognition of own- and other-race faces.

The efficiency of wireless power transfer (WPT) systems is highly dependent on the load, which may change in a wide range in field applications. Besides, the detuning of WPT systems caused by the component tolerance and aging of inductors and capacitors can also decrease the system efficiency. In order to track the maximum system efficiency under varied loads and detuning conditions in real time, an active single-phase rectifier (ASPR) with an auxiliary measurement coil (AMC) and its corresponding control method are proposed in this paper. Both the equivalent load impedance and the output voltage can be regulated by the ASPR and the inverter, separately. First, the fundamental harmonic analysis model is established to analyze the influence of the load and the detuning on the system efficiency. Second, the soft-switching conditions and the equivalent input impedance of ASPR with different phase shifts and pulse widths are investigated in detail. Then, the analysis of the AMC and the maximum efficiency control strategy are provided in detail. Finally, an 800-W prototype is set up to validate the performance of the proposed method. The experimental results show that with 10% tolerance of the resonant capacitor in the receiver side, the system efficiency with the proposed approach reaches 91.7% at rated 800-W load and 91.1% at 300-W light load, which has an improvement by 2% and 10% separately compared with the traditional diode rectifier.

HEPS-BPIX3 is a hybrid pixel detector readout chip for X-ray applications for the High Energy Photon Source (HEPS) in China. The readout chip contains an array of 88 × 88 pixels with a pixel size of 55 μm × 55 μm, working in single photon counting mode. Each pixel handles both polarities of positive and negative input charge signals and has a counting depth of 11 bits. Using a clock with a frequency up to 160 MHz, the chip can read out serially with zero dead time. Designed in a 130 nm CMOS technology, the chip has been measured and given the CSA charge gain of 17.6 mV/ke- for electron collection and 13 mV/ke- for hole collection, respectively. Bump-bonded detector modules with a 320-μm-thick silicon sensor were also tested. The test results showed an equivalent input noise of 156 e- and a counting rate up to 2.2 Mcps. Besides, an image using an X-ray tube was demonstrated and a frame rate of 1.8 kHz could be guaranteed. Measured characteristics present the normal functionality of the HEPS-BPIX3 chip and prove that the chip satisfies the HEPS requirements.

This paper presents a new approach to the classical method for failure detection with eddy currents. In contrast to traditional methods of measuring reflected impedance on the probe circuit, this paper uses concepts of identification theory to find a transfer function that characterizes the dynamics of the measuring system by eddy currents. The transfer function represents the admittance of the input equivalent circuit. The estimated parameters of the transfer function were used to compute the inductive time constant of equivalent circuit of the metal specimen. The results of the time constant variation of the equivalent circuit of the sample were compared with the equivalent input impedance variation. A preliminary analysis is done in a simple case study, which has shown that the inductive time constant is more sensitive than the reflected impedance on the probe circuit, especially at low frequencies. Moreover, the estimated time constant is independent of the excitation frequency and mutual inductance.

The optimal design of Induction Magnetometer (IM) is a prevalent and practical issue. A major combinatorial optimization problem is to design an IM so that it operates optimally in the sense of producing minimal equivalent input magnetic noise level and having the minimal total weight. In this paper, we constructed a desirability function that combines the above two conflicting criteria and proposed a novel Adaptive Chemical Reaction Optimization based on Stimulating Strategy (SE-ACRO) to address this multi-objective optimization problem. CRO is a newly developed evolutionary algorithm inspired by the interactions between molecules in chemical reactions. In the proposed SE-ACRO, on the basis of the original CRO, we further introduced probability selection mechanism and stimulating strategy to improve the performance of the algorithm. In addition, the adaptive mechanism was used for the adjustment of some parameters in CRO. Simulation results demonstrate that the proposed SE-ACRO algorithm is highl...

A constrained adaptive neural network control scheme is proposed for a multi-input and multi-output (MIMO) aeroelastic system in the presence of wind gust, system uncertainties, and input nonlinearities consisting of input saturation and dead-zone. In regard to the input nonlinearities, the right inverse function block of the dead-zone is added before the input nonlinearities, which simplifies the input nonlinearities into an equivalent input saturation. To deal with the equivalent input saturation, an auxiliary error system is designed to compensate for the impact of the input saturation. Meanwhile, uncertainties in pitch stiffness, plunge stiffness, and pitch damping are all considered, and radial basis function neural networks (RBFNNs) are applied to approximate the system uncertainties. In combination with the designed auxiliary error system and the backstepping control technique, a constrained adaptive neural network controller is designed, and it is proven that all the signals in the closed-loop system are semi-globally uniformly bounded via the Lyapunov stability analysis method. Finally, extensive digital simulation results demonstrate the effectiveness of the proposed control scheme towards flutter suppression in spite of the integrated effects of wind gust, system uncertainties, and input nonlinearities.

In this paper, we investigate the responsivities and output voltage noise power spectral densities of magnetoelectric (ME) laminate sensors, consisting of length magnetized Terfenol-D alloys and transverse/width poled Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PMNT) crystals (i.e. L-T mode and L-W mode respectively), which are directly integrated with custom-build low noise charge amplifier circuits. Both the theoretical analyses and experimental results prove that the L-W mode sensor with the optimized polarized direction of the PMNT plate possesses lower magnetic detection limit at the interested high frequency range of 10 kHz≤ f ≤50 kHz. The equivalent magnetic noise ( EMN ) of the L-W mode sensor is 0.78 pT/Hz 1/2 at 30 kHz, which is about 1.7 times lower than the 1.35 pT/Hz 1/2 for conventional L-T mode sensor. Furthermore, an effective method of using operational amplifiers with low equivalent input noise voltage and employing ME laminate composites with high voltage coefficient to reduce the EMN s of the ME laminate sensors at high frequency range has been established.

Distribution networks may be disturbed by lightning in case of either direct strikes to the line conductors or nearby strokes. In order to evaluate the lightning transients and their impact on a power distribution network, the knowledge of the response of the main system components when subjected to the resulting surges is of essential importance. The radial configuration is characterized, on the one hand, by minimal control of power flow, and, on the other hand, by straightforward circuit design, easy fault current protection, and low cost. In this paper power distribution networks, along with models of the main system components, including poles, transformers, insulators, surge arresters, SPDs, grounding systems, and the equivalent input impedance of LV power installations. The models are very useful as they are reliable, relatively simple, and can be used in programs for the evaluation of lightning electromagnetic transients in MV and LV networks.

The realization of zero-voltage switching (ZVS) of inverter can reduce the circuit switching loss. It meets the high power density requirements of the inductive power transfer (IPT). To achieve ZVS, it is necessary to consider the matching of impedance properties to dead-band. Therefore, based on the input equivalent impedance and dead-band, the conditions for achieving ZVS are studied in this paper. Firstly, the equivalent input impedance model is established based on secondary-side full compensation and the switching process is analyzed in the case of ZVS. Secondly, based on the above model, the dead-band range of ZVS is derived. Then, the influence of the primary-side compensation capacitor on the ZVS is discussed, which provides a theoretical basis for fine-tuning the compensation capacitor. Finally, the feasibility of the method is verified by simulation.

In this paper a comparison between a LCCL and CLLC resonant compensations for Capacitive Wireless Power Transfer (CWPT) system is presented. A review of several compensation topologies is presented. From this analysis emerges that these two topologies represent the more promising compensation for high power applications, such as Electric Vehicle (EV) wireless charging. The frequency behavior of each topology is analyzed studying the equivalent input impedance and the voltage transfer function. After design of each compensation to operate at optimum operating condition, the output power and the efficiency are evaluated under load, coupling parasitic resistances variations through LTspice simulations.