谐振式环形管科里奥利质量流量计

给出了一种建立在驱动与科里奥利（coriolis)模态固有频率相等、连续信号处理技术和频率跟踪法基础上的谐振式环形管coriolis质量计量计。在驱动模态与coriolis模态固有频率相等的条件下,当环形管有流体流过时环形管就处于谐振状态,因此具有较高的灵敏度;由于该质量流量计输出信号是连续的,所以可采用连续信号处理技术,得到较高的检测精度;流体密谋的检测是采用自激振荡原理和频率跟踪法得到的。文章还详细给出了该质量流量计的数学模型和检测原理。     

一种新型硅微陀螺仪闭环驱动方案的研究

研究了一种新的硅微陀螺仪闭环驱动方案,对推挽驱动方式的性能进行了分析,结果表明驱动力矩的频段与噪声信号频段是分离的,因此噪声信号不会影响到驱动效果。在此基础上,利用锁相技术满足正弦自激振荡的相角和增益条件,建立环路的自激振荡,实现了闭环控制。同时在闭环回路中利用正弦自激振荡的相角条件和锁相环的鉴相特性,消除了驱动信号对敏感信号的同频干扰,并抑制了环路中的噪声干扰,明显提高闭环性能。试验结果显示在1小时内交流信号频率和幅度的标准方差分别为0.132 H z和0.258 mV,实现了驱动稳幅稳频的目的,从而使陀螺仪精度和可靠性得到了显著提高。     

A highly effective load adaptive servo drive system for speed control of travelling-wave ultrasonic motor

This paper presents a highly effective load adaptive drive system to control the speed of a travelling-wave ultrasonic motor. The motor driver was built based on the two-phase high-frequency inverter using the mechanical resonant frequency of the ultrasonic motor. To digitally control the drive system, a TMS320F243 digital signal processor was adapted to the driver. The developed system includes two feedback loops; speed control loop and feedback voltage-resonant frequency tracking loop. The driving frequency was used as a control input to control the motor. Direct pulse-width modulation (PWM) control was used to obtain the required driving frequency. The developed drive system was experimentally tested under several operating conditions. The obtained results demonstrated the effectiveness of the drive system for high performance drive applications.     

A new short-time high-overload BLDC driving system based on electronic flywheel and time-division switching control

Most of the existing (BLDCM) brushless dc motor drive systems are designed with the traditional drive scheme for long-time operation. For short-time and heavy-duty applications, there are problems of energy consumption, large volume, heavyweight and high-cost. In this paper, a new short-time high-overload BLDCM drive system based on "electronic flywheel" and time-division switching control is proposed, which includes three core contents: a crushing chamber based on combined cutter head, an energy storage device based on an "electronic flywheel" and high overload factor BLDC using a new calculation method of capacitance and a speed control system based on time-division switching control of the speed loop and the current loop. To prove the effectiveness of the proposed scheme, a kitchen garbage processor is developed and tested. The results show that the "electronic flywheel" energy storage driving device designed in this paper is able to provide most of the energy required in the heavy-duty driving process. The designed time-division switching control scheme can well meet the control requirements for the short-time heavy load drive of the kitchen waste processor. Compared with the traditional long-time rated load drive scheme, the proposed system has the advantages of energy-saving, small volume, lightweight and low-cost.     

Small signal analysis of the LCC-type parallel resonant converterusing discrete time domain modeling

Discrete state-space modeling of the LCC-type parallel resonant power converter is presented. Using these large signal equations, small signal modeling of the power converter is obtained. Multiple loops have been used for the closed loop operation. State variable feedback control has been integrated with the linear small signal state-space model and the associated control aspects are studied. The small signal state-space model has been used to study the small signal behavior of the power converter for open loop and closed loop operation for parameters like control to output transfer function, audio-susceptibility and output impedance. Key theoretical results have been experimentally verified     

Phase-Locked Loop Coherent Combiners for Phased Array Sensor Systems

Phase-locked loops (PLL's) may be used to implement signal combiners which coherently sum multiple signals from an array of sensors. In each combiner channel, the sensor signal is simultaneously downconverted to an intermediate frequency (IF) signal and phase-locked to an appropriately generated reference signal by a "long-loop" PLL. This loop maintains a nominal 90° phase difference between the IF signal and the reference signal irrespective of phase of the channel input (sensor output) signal. The channel IF signals are summed to generate the combiner output signal. The reference signal may be a locally generated sine wave or a delayed version of the combiner output signal. Imperfect phase control and, thus, imperfect signal combining results when noise voltages are associated with the channel signals. In this paper, a lincarized model of a PLL coherent combiner is developed. This model applies when the desired channel signals are equal amplitude and angle modulated; the channel noise voltages are equal level, Gaussian distributed, and independent; and the combiner phase errors are appropriately small. This model is then used to derive equations for the variance of differential phase errors associated with combiner operation and to show the effect of these phase errors on the average power in the combiner output signal. Relevant experimental results from a four-channel combiner are compared with the performance predicted by the linear model.     

On the Mode-Matched Control of MEMS Vibratory Gyroscope via Phase-Domain Analysis and Design

This paper investigates a novel method for the mode-matched control of a microelectromechanical systems (MEMS) vibratory gyroscope through a phase-domain analysis. Compared with the previous works, the proposed method presents a simple and robust automatic mode tuning scheme for sensitivity enhancement. In designing the mode-matched control loop, the resonant characteristics of the driving axis are used as the reference mode. Then, the phase difference between sense and drive modes at the resonant frequency of drive mode is used to generate a control signal for phase error regulation. For the control loop design, a linear phase-locked loop is adapted. Through the simulation using practical MEMS gyroscope parameters, the mode-matching performance and robustness of the designed control loop is demonstrated. It is also shown that coupling effect yields no degradation of output sensitivity. Finally, the experimental results obtained by implementing the electronics of mode-matched control verify the feasibility of the proposed method.      

基于欧拉回路的无线传播模型校正路测路径优化方法研究

为了提高无线传播模型校正等路测工作中路径规划的准确性,本文利用图论中的欧拉回路概念,结合中国邮路问题的相关研究,综合考虑测试区域的道路拓扑结构、路径长度、交通规则等因素,提出一种基于欧拉回路并采用改进的深度优先搜索算法实现的道路测试路径优化方法.该方法可以实现自动生成最优测试路线,提升了路测效率.     

基于压缩采样结构的盲多带信号预失真模型

针对在支撑集未知的情况下重构多频带信号的问题,本文提出了一种基于压缩采样结构的盲多带信号预失真模型,即将多频输出信号视为单个宽带信号,经下变频和低通滤波器处理后,送入A-MWC (Alternate Modulated Wideband Converter)结构进行盲压缩采样,而后通过基于随机支撑挑选的变步长稀疏度自适...     

Optimum design of transferred-electron amplifier devices in GaAs

The paper concern the design of GaAs transferred electron amplifying diodes with a cathode doping notch. Simple analytical expressions for small signal impedance and noise factor are expressed in terms of the growth factor and transit phase angle for a constant electric field notch device. These are compared to experimental results, measured on such a device, and the agreement is remarkably good considering the simple model. A minimum measured noise figure of 10.5 dB was obtained. The gain saturation curves are given and briefly discussed. Although at higher frequencies, a small gain increase is encountered with increasing drive a properly controlled notch device does not show a marked gain jump at higher levels as is frequently encountered with Gunn amplifiers.     

无传感器交流传动技术的展望

在电机轴上无机械速度传感器的可控交流电机驱动，由于其低廉的价格和较高的可靠性，一直备受关注。为了取代传感器，它通过测量定子电流和电机端电压得到转子速度信息。矢量控制传动需要估计定子或转子磁通基波的大小和空间位置。为此需要使用开环估计器或闭环观测器，它们在准确性、鲁棒性以及对模型参数变化的敏感性等性能上均不相同。通过信号注入即利用电机的各向异性，可以获得零速范围附近的动态性能和稳态速度精度。本文使用复杂空间矢量的信号流程图来形象地描述交流电机无传感器的控制系统。     

Performance of PLL Synchronized Optical PPM Communication Systems

Receiver timing synchronization of an optical PPM communication system can be achieved using a phase-locked loop (PLL) if the photodetector output is properly processed. The synchronization performance is shown to improve with increasing signal power and decreasing loop bandwidth. The bit error rate performance of the PLL synchronized PPM system is analyzed and compared to that of the perfectly synchronized system. It is shown that the increase in signal power needed to compensate for the imperfect synchronization is small (less than 0.1 dB) for loop bandwidths less than 0.1 percent of the slot frequency.     

开关电源驱动信号斜率补偿技术的研究

对电流型PWM控制器的扰动来源进行分析，给出了解决办法和几种比较实用的斜率补偿电路，如控制电压补偿方式和电流补偿方式，对改善开关电源驱动信号稳定性有很好的效果。最后给出了一种电流环补偿电路实例予以验证。     

Mechanical sensorless speed control of permanent-magnet AC motors driving an unknown load

A new sensorless scheme for high-performance speed control of permanent-magnet ac motors (PMACMs) driving an unknown load is proposed. This scheme uses an extended nonlinear reduced-order observer to estimate the induced electromotive force (EMF) and load torque. From the estimated variables, the rotor position, the rotor speed, and the position derivative of flux are calculated and are used to close the control loop. In order to improve the drive performance, the estimated load torque is incorporated as a feedforward signal in the closed control loop. In addition, the proposed sensorless PMACM drive allows the torque-ripple and copper-loss minimization for motors with an arbitrary EMF waveform. Simulation and experimental results to validate the proposal are presented in this paper.     

双频GPS接收机的动态辅助L2P(Y)跟踪

双频接收机中对L2P(Y)信号的跟踪可以使用半无码方法.但由于半无码方法本身具有平方损耗,因此实际获得的L2P(Y)信号载噪比很低,对L2P(Y)信号跟踪环路的性能提出了更高的要求.文中提出了一种利用接收机动态辅助L2P(Y)码跟踪的方法,给出了环路的设计细节,并详细地讨论了影响环路性能的各个因素.通过计算机仿真,比较了动态辅助环路和未辅助环路的性能.仿真结果表明,使用动态辅助的L2P(Y)信号跟踪环路可以在更低的载噪比下进行有效跟踪.     

Comparative analysis of experimental performance and stability of sensorless induction motor drives

This paper compares the experimental performance of three flux and speed observers for speed-sensorless induction motor drives and discusses the cause of their differences. The small signal analysis using the linearized model is carried out to analyze stability. Three methods are generally accepted to be representative candidates for high sensorless performance, namely: 1) rotor-flux model reference adaptive system (MRAS); 2) torque-current MRAS; and 3) adaptive nonlinear flux observer. Many other sensorless methods improved these methods. The paper discusses baseline conditions for the experiments and the stability analysis, which include matched load inertia, specified speed estimator dynamics, and sensorless operation within a speed control loop. For the comparison tests in the paper, the speed estimation dynamics of the methods are the same; this is important for parameter sensitivity. The paper concentrates on the low-speed performance, and all results shown are under sensorless speed control.     

Modeling of output resistance in SiGe heterojunction bipolartransistors with significant neutral base recombination

A simple compact model, suitable for circuit simulations, is derived which enables quantitative determination of the impact of neutral base recombination on the small signal ac output resistance of SiGe HBT's for arbitrary base ac drive conditions. The model uses existing SPICE parameters which are routinely extracted from bipolar transistors plus an additional model parameter which can be extracted from a proposed experimental technique involving output resistance measurements under base ac voltage and current drive conditions. The modeling approach also enables the forward and reverse base transit times to be related to transistor small signal ac output resistance by a simple analytic expression. The currently accepted expression for the r _μ parameter, which is used to model neutral base recombination in the ac hybrid-π equivalent circuit, is shown to be incorrect and is replaced by a new correct expression. Numerical simulations of a SiGe HBT structure which exhibits neutral base recombination are used to verify the validity of the model     

基于74HC4046AD的感应加热电源设计

针对感应加热过程中,铁质负载的电阻率和磁导率会发生变化,使谐振频率发生变化的情况,文中介绍了一种锁相驱动方案。该方案可以实现负载频率自动跟踪,它的电路包括锁相环电路、同步信号提取电路和隔离驱动电路三部分。其中锁相电路实现负载频率的跟踪,同步信号提取电路和隔离驱动电路实现IGBT驱动。设计并制作一台2.5 kW/20 kHz感应加热电源样机,通过给注塑机炮筒加热,实验数据表明锁相驱动方案锁相稳定。     

带光耦双闭环反激式开关电源小信号模型分析

双闭环控制在开关电源中的应用非常普遍,是因为它使系统具有较好的动态性和稳定性。文章就是在双闭环控制的反激电路中,分析了反激变换器的功率级电路的平均模型和控制电路中TL431和光耦器件的非理想模型;运用控制理论写出整个变换器系统闭环的环增益,并且用网络分析仪测出系统环增益,结果表明系统具有良好的稳定性和动态性。     

3RR测量系统的高精度新型应答机设计

介绍了一种基于3RR应测量系统的三通道高精度新型应答机,该应答机采用一路相参、两路非相参的方案。比较了中频调制转发（中转调）和中频混频转发（中转发）两种方案的特点,并对特殊环路设计、多路信道带宽设计和强弱信号增益线性设计等关键技术进行了详细论述。