有源滤波器的三相四线制谐波检测新方法研究

基于瞬时无功理论的传统有源滤波器在三相四线制电路中不适用,文章针对这个问题,综合运用瞬时无功理论中的p-q方法和ipi-q方法,提出了一种新的基于瞬时无功理论的有效的三相四线制谐波检测新方法,将三相电流中的零序电流剔除,完善了p-q方法和ip-iq方法的不足,通过计算验证了该方法适用于任何三相电路,包括三相四线制电路,并且三相电压波形的畸变不影响检测结果的准确性。并用MATLAB仿真验证了该方法的准确性和有效性。该方法有效地解决了传统有源滤波器不适用于三相四线制电路的缺陷。     

激光陀螺随机漂移的渐消Kalman滤波

随机漂移误差是激光陀螺的主要误差源之一.Kalman滤波算法能够有效抑制激光陀螺的随机误差,但是当计算模型不准确时,采用常规Kalman滤波易导致结果发散.渐消Kalman滤波能够抑制历史信息、重用现时量测信息,得到连续平稳的滤波结果.采用渐消Kalman滤波对激光陀螺随机漂移进行最优估计,取得了较好的效果.结果表明,...     

一种面向多标准无线收发器的低功耗宽调谐范围基带滤波器设计

本论文提出了一种面向多标准收发器的具有精确片上调谐电路的低功耗宽调谐范围基带滤波器。设计的滤波器是由三级Active-Gm-RC类型的双二次单元级联组成的六阶巴特沃斯低通滤波器。采用改进的线性化技术来提高低通滤波器的线性度。论文提出了一种新的匹配性能与工艺无关的跨导匹配电路和具有频率补偿的频率调谐电路来增加滤波器的频率响应精度。为了验证设计方法的有效性,采用标准的130nm CMOS工艺对滤波器电路进行流片。测试结果表明设计的低通滤波器带宽调谐范围为0.1MHz-25MHz,频率调谐误差小于2.68%。滤波器在1.2V的电源电压下,功耗为0.52mA到5.25mA,同时取得26.3dBm的带内输入三阶交调点。     

Online control of current-source-type active rectifier usingtransfer function approach

Current-source topology AC/DC converters (buck converters) operated using pulsewidth modulation have significant drawbacks in lack of line current control and AC-side filter damping. Also, an AC-side filter is usually overrated in order to keep harmonic distortion under imposed limits. Discontinuous current at converter line inputs disables the use of current control techniques known from control of voltage-source converters. In order to overcome these problems, an online control method for the buck converter is presented in this paper. This method is based on the AC filter transfer function approach. Such an approach enables a novel solution for line-side filter optimization in the case of hysteresis line current control. This method leads to a filter with minimal apparent power (cost) and the fast and accurate converter's control response. Furthermore, a line current estimation method was developed. It uses only one current sensor at the converter DC side in order to estimate power supply currents. Suggested methods were numerically and experimentally verified     

A technique for power supply harmonic impedance estimation using acontrolled voltage disturbance

A method for power system impedance estimation is presented. The method employs a power converter to inject a voltage transient onto the supply system. As the technique employs controlled power electronic devices it may be used as a stand alone piece of a portable measurement equipment, or it may be embedded into the functions of an active shunt filter for improved harmonic control. The impedance is estimated through correlation of the measured voltage and current transients. Simulations and experimental results demonstrate the measurement technique is highly accurate and effective     

基于小波变换的电能质量暂态分析

随着国家工业规模的扩大和科学技术的发展,电的使用越来越广泛,电力负荷迅速增加,对电网运行状态进行高效而准确的检测分析具有重大意义。相对于稳态分析,暂态分析的难点在于快速、及时地捕获信号突变和进行准确、稳定的分析。对于暂态信号突变的检测,该文从微分算子可以监测突变的特性出发,发现了小波滤波器Ⅳ阶消失矩和Ⅳ次卷积微分算子的等价关系,并对小波滤波器的检测能力做出了分析。     

Real-Time Estimation of Fundamental Frequency and Harmonics for Active Shunt Power Filters in Aircraft Electrical Systems

A novel algorithm for fundamental frequency and harmonic components detection is presented in this paper. The technique is based on a real-time implementation of discrete Fourier transform, and it allows fast and accurate estimation of fundamental frequency and harmonics of a distorted signal with variable fundamental frequency. It is suitable for active shunt filter applications, when fast and accurate tracking of the reference signal is required to achieve a good control performance. The main application for the algorithm is aircraft ac power systems, where the fundamental frequency can be either fixed on 400 Hz and its actual value fluctuates around the nominal value, or variable in the range 360–900 Hz. Hence, a real-time estimation of fundamental frequency is essential for active filter control. The proposed algorithm has been at first implemented in Matlab/Simulink for computer simulation, and it has been compared with a Phase Locked Loop (PLL) algorithm for frequency detection and the synchronous $dq$ reference method for harmonic detection. Experimental tests have been carried out in order to validate the simulation results. The distorted current absorbed by a nonlinear load is analyzed and processed by means of a digital implementation of the algorithm running on the active shunt power filter control DSP, in order to calculate the active filter compensating current.      

Deconvolution of tracer and dilution data using the Wiener filter

In the study of living systems it is often necessary to inject or infuse a substance into the peripheral circulation and monitor its subsequent concentration in the plasma with time. Examples abound in the pharmacokinetic study of drugs and in the use of the indicator dilution technique for measuring blood flow. Furthermore, it is often necessary to deconvolve one such measured, and hence noisy, data set with another. One of the standard methods for deconvolving noisy signals is the Wiener filter, which is generally derived as a real window in the frequency domain such that the mean squared error between the estimated deconvolved function and the truth, on average, is minimized. Application of the Wiener filter requires some (often crude) model of the noise-to-signal power ratio as a function of frequency. In the pharmacokinetic and indicator dilution situations, however, one invariably has a good model of the actual function to be deconvolved in the form of a sum of decaying exponential functions. Such a model may be employed to calculate the signal-to-noise power ratio for use in the Wiener filter, or alternatively may be directly deconvolved itself. It is shown that better results are achieved with the Wiener filter if the model of the signal is not particularly accurate, whereas with a very accurate model it is better to deconvolve the model itself. The point at which the two deconvolution approaches perform comparably occurs when the error in the model is of a similar magnitude to the noise.     

Power estimation methods for analog circuits for architecturalexploration of integrated systems

This paper describes methods for analog-power estimation and applies them practically to two different classes of analog circuits. Such power estimators, which return a power estimate given only a block's specification values without knowing its detailed circuit implementation, are valuable components for architectural exploration tools and hence interesting for high-level system designers. As an illustration, two estimators are presented: one for high-speed analog-to-digital converters (ADCs) and one for analog-continuous time filters. The ADC power estimator is a technology scalable closed formula and yields first-order results within an accuracy factor of about 2.2 for the whole class of high-speed Nyquist-rate ADCs. The filter-power estimator is of a more complex nature. It uses a crude filter synthesis, in combination with operational transconductor amplifier behavioral models to generate accurate results as well, but restricted to certain filter implementations     

Optimum design of Nd-doped fiber optical amplifiers

The waveguide parameters for a Nd-doped fluoride (Nd:ZBLANP) fiber amplifier have been optimized for small-signal and booster operation using an accurate numerical model. The optimum cutoff wavelength is shown to be 800 nm and the numerical aperture should be made as large as possible. Around 80% booster quantum conversion efficiency can be reached for an input power of 10 dBm and a pump power of 100 mW by the use of one filter     

Design and evaluation of a high-precision, fully tunable OTA-Cbandpass filter implemented in GaAs MESFET technology

A second-order bandpass filter employing the operational transconductance amplifier-capacitor (OTA-C) method and featuring independent tuning of center frequency and Q is described. The filter, which is realized in 0.5-μm GaAs MESFET technology, is intended for use in high-precision, continuous-time (CT) IF bandpass filtering applications requiring both accurate amplitude and group delay responses. The filter center frequency is tunable in the range 12-50 MHz, Q is tunable in the range 4-60, and a transfer function accuracy of the order of 1% is achieved throughout the tuning range. Active area is 1 mm² and static power consumption is 230 mW     

Modeling the Effect of Voltage Ripple on the Power Output of Photovoltaic Modules

This paper proposes a model for the static power loss in photovoltaic (PV) panels due to switching-frequency ripple. Small-signal modeling is used to determine the amplitude of the voltage ripple that is imposed on the PV panel, and a closed-form expression is developed for the output power. The expression is shown to be more accurate than the power loss that was predicted by small-signal modeling alone, resulting in a median error of 0.8%. The model presented allows dc-dc converter designers to more precisely choose the input filter components that are critical during times of low insolation.     

基于最小均方和递归最小二乘的有源滤波器谐波检测

针对当前有源滤波器谐波检测算法的精度低、运算量大、实时性差等不足,为了获得更加理想的谐波检测结果,提出了基于最小均方和递归最小二乘的有源滤波器谐波检测算法。首先针对锁相环获取输入信号运算量大、谐波检测时间长的难题,将过负载电流作为参考输入,加快有源滤波器的响应速度,然后基于最小均方算法和递归最小二乘算法快速、准确的实现谐波检测,最后在MATLAB 1204平台对本文算法的有效性和先进性进行了仿真验证性实验。 实验结果表明,本文算法得到了较高的有源滤波器谐波检测精度,能够提高有源滤波器的补偿性能,而且具有较快的动态响应速度,改善了算法的实时性。     

A new simple method for analysing of thermal noise in switched-capacitor filters

Thermal noise is one of the most important challenges in analogue integrated circuits design. This problem is more crucial in switched-capacitor (SC) filters due to the aliasing effect of wide-band thermal noise. In this article, a new simple method is proposed for estimating the power spectrum density of output thermal noise in SC filters, which have acceptable accuracy and short running time. In the proposed method, first using HSPICE simulator, accurate value of accumulated sampled noise on sampler capacitors in each clock state is achieved. Next, using difference equations of the SC filter, frequency response of the SC filter is shaped by time domain analysis. Based on the proposed method, a SC low-pass filter and a second-order SC band-pass filter are analysed. The results are validated by comparing to the previously measured data.     

截止频率精确可调跨导电容滤波器实现

提出了一种新的利用开关电容技术调节偏置电流值大小的电路,应用该电路可以精确调节跨导运放Gm值的大小。采用既具有电压共模负反馈(CMFB)电路, 又同时具有工作在线性区的MOS管作源极反馈有源电阻, 实现其良好线性度的跨导运放。设计了三阶椭圆函数低通滤波器,并实现其频率的精确可调。应用台积电(TSMC)2层多晶硅,4层金属(2P4M),3.3V电源电压,0.35m CMOS工艺Spice model仿真得到的频响曲线与理想情况十分接近。     

PTF-based control algorithm for three-phase interleaved inverter-based SAPF

In this paper, modelling and hardware implementation of three-phase interleaved inverter-based shunt active power filter (SAPF) is proposed to mitigate current harmonics, reactive power for ensuring unity power factor and load balancing without shoot-through effect. Shoot-through effect is one of the hazardous issues in conventional voltage source inverters such as damage of power electronic switches, electromagnetic interference, ringing in the power circuitry. The present power system has inevitable non-linear loads which create large variations in the supply voltage distortions. Therefore, the compensation capability and efficiency of the SAPFs degrades. A novel predictive tuned filter is proposed in this paper to estimate the variations in the amplitude of supply voltage, frequency and harmonics for extracting the fundamental voltage signal. The fundamental extracted signal is further processed for reference current generation using generalized p-q theory. The performance of the proposed system is simulated using MATLAB®/Simulink environment and tested under different supply voltage conditions. The simulation results have been validated by developing a prototype in the laboratory by using a dSPACE1104 controller. It is found from the simulated and experimental results that the proposed system is fast, robust and accurate which improves the power quality without shoot-through problem.     

A UWB-IR Transmitter With Digitally Controlled Pulse Generator

A novel transmitter for ultra-wideband (UWB) impulse radio has been developed. The proposed architecture enables low-power operation, simple design, and accurate pulse-shape generation. The phase and amplitude of the pulse are controlled separately and digitally to generate a desired pulse shape. This digital control method also contributes to the low-power transmission and eliminates the need for a filter. The transmitter is fabricated using a 0.18-mum CMOS process. The core chip size is only 0.40 mm². From experimental measurements, it was found that the generated signal satisfied the FCC spectrum mask, and the average power dissipation was only 29.7 mW at A 2.2-V supply voltage. Therefore, the developed UWB transmitter generates accurate pulses with low power consumption and simple design architecture     

Electromechanical-Filter-Based Bandpass Sigma–Delta Modulator

This brief proposes an electromechanical-filter-based continuous-time (CT) bandpass (BP) sigma-delta modulator for wideband digitization at high intermediate frequency (> 70 MHz). Both the mechanically coupled microelectromechanical system and the longitudinally coupled surface acoustic wave (SAW) filters can be employed as loop filters. The advantages of the electromechanical filter are its low power consumption and accurate center frequency without the need for tuning. As a proof of concept, a fourth-order BP sigma-delta modulator is demonstrated with a 110-MHz SAW filter. Realized in a 0.35- mum SiGe heterojunction-bipolar-transistor bipolar complimentary metal-oxide-semiconductor technology, the prototype chip is clocked at 440 MHz and achieves 65-dB DR and 60-dB SNDR over 1 MHz, as well as 58-dB DR and 53-dB SNDR over the 3.84-MHz signal band. The total power consumption is 57 mW under a 3-V supply.     

A Novel Dual-Rate Sampling Switched-Capacitor Configuration and Its Application

In order to realize accurate bilinear transformation from s- to z-domain,a novelswitched-capacitor configuration is proposed in the light of principles of dual-rate sampling and chargeconservation,which has also been used for building a 5th-order elliptic lowpass filter.The filter issimulated and measured in typical 0.34 μm/3.3 V Si CMOS process models,special full differentialoperational amplifiers and CMOS transfer gate switches,which achieves 80 MHz sampling rate,17.8MHz cutoff frequency,0.052 dB maximum passband ripple,42.1 dB minimum stopband attenuation and74 mW quiescent power dissipation.At the same time,the dual-rate sampling topology breaks thetraditional restrictions of filter introduced by unit-gain bandwidth and slew rate of operational amplifiersand also improves effectively their performances in high-frequency applications.It has been applied forthe design of an anti-alias filter in analog front-end of video decoder IC with 15 MHz signal frequencyyet.     

Quantization and roundoff noises in fixed-point FIR digital filters

The errors in a fixed-point finite impulse response (FIR) filter due to quantization (analog-to-digital conversion) and roundoff are considered. Expressions for the exact moments of the filter output noise are derived. It is well known that, when the input signal satisfies certain conditions, the popular additive white noise model can be valid in describing the quantization noise. The characteristics of multiplicative roundoff noises, however, differ from what this model predicts, even under conditions where the roundoff noises are white. Hence the additive white noise model does not provide accurate results on the characteristics of the output error in an FIR filter. Using the exact formulas for the moments, the author computes the exact power spectrum of the filter output error. These results agree well with those obtained from simulation