Modeling the sequential switching shunt series regulator

This letter characterizes, in terms of the bandwidth and limit cycle frequency of its constituent subsystems, the sequential switching shunt series regulator -S/sup 4/R, a high-efficiency, low-mass and volume power cell devised to power the next generation of regulated power buses in telecommunication spacecrafts. Transconductance power source modeling is used to obtain linear and nonlinear models. These are used to establish a design control strategy which involves the dynamic response in large load requirements or at the end of the satellite life. Simulations and experimental results are also given to demonstrate the validity of the model.     

A dual-loop shunt regulator using current-sensing feedback techniques

The dual-loop shunt regulator using current-sensing feedback techniques is proposed in this paper. This architecture adopts a voltage and current loops to increase the transient response of the proposed shunt regulator. The maximum output current of the proposed shunt regulator is 180 mA at a 1.8 V output. Moreover the architecture of the proposed shunt regulator can suppress the stray effect which is from power supply. The prototype of the proposed shunt regulator is fabricated by the Taiwan Semiconductor Manufacturing Corporation (TSMC) 0.35-μm CMOS 2P4M process. The active area is only 579×355 μm².     

基于改进型PR调节器的三相PWM整流器控制

应用三相PWM整流器在两相静止坐标系下电流矢量αβ分量的可解耦控制,解决了传统的基于两相旋转坐标系下三相PWM整流器控制系统电流矢量dq分量无法解耦控制的问题,提高了系统的控制性能。且采用改进型PR调节器控制代替传统的PI调节器控制能够对指定频率的交流信号实现稳态无静差跟踪控制,有效抑制低次谐波和高次谐波;相比于传统PR调节器对于系统波动过于敏感的特点,改进型PR调节器在能够保持谐振频率处的敏感度和高增益的基础上,可以增强系统稳定性。对此系统进行Matlab/Simulink仿真分析,验证了该方法的可行性。     

A new current-mode fast-transient-response shunt regulator using CMOS technology

The demand for current-mode fast-transient-response shunt regulator is increasing for the growth of portable electronics, such as cellular phones, PDA, laptops, etc. A new current-mode fast-transient-response shunt regulator is presented in this paper. The proposed shunt regulator used a single Miller compensation capacitor to increase stability. The current-mode shunt regulator helps the transient response to be faster than the voltage-mode low-dropout regulator (LDO) and the power noise (bounce noise) is smaller than one. The proposed current-mode shunt regulator has been fabricated with TSMC 0.35 μm 2P4M CMOS technology. The experimental results show the transient-response time is only 400 ns within 0.5% error and the maximum output voltage dip is only 70 mV for full loading current variation. Moreover, the line and load regulations are 26 μV/mA and 8 ppm/mA, respectively. The dropout current is 1.0741 mA for loading current 150 mA. The active chip area is 226 μm × 310 μm.     

Adjustable speed control of ultrasonic motors by adaptive control

The driving principle of the ultrasonic motor (USM) is different from those of the electro-magnetic type motors. Some mathematical models for the USM have been reported; however, these models are very complex to apply for speed control of the USM. Therefore, the speed controllers have been designed using PI controllers or fuzzy controllers and it is necessary to develop a simple and convenient mathematical model for the USM in order to achieve a high-performance speed control. In this paper, a mathematical model for the USM is proposed which is simple and useful for speed control. The speed controller is designed based on the model using adaptive control theory. Adaptive control is attractive for control of the USM because the speed characteristics of the USM vary with drive conditions. The application of this control scheme to speed control for the USM is attempted first. The effectiveness of proposed control is demonstrated by experimental     

Disturbance observer based control for nonlinear systems

This work presents a general framework for nonlinear systems subject to disturbances using disturbance observer based control (DOBC) techniques. A two-stage design procedure to improve disturbance attenuation ability of current linear/nonlinear controllers is proposed where the disturbance observer design is separated from the controller design. To facilitate this concept, a nonlinear disturbance observer is developed for disturbances generated by an exogenous system, and global exponential stability is established under certain condition. Furthermore, semiglobal stability condition of the composite controller consisting of a nonlinear controller and the nonlinear disturbance observer is established. The developed method is illustrated by the application to control of a two-link robotic manipulator.     

基于FPGA的可调信号发生器

基于FPGA的应用技术,采用Altera 公司 DE2-70开发板的Cyclone Ⅱ系列EP2C70作为核心器件,设计了一种基于FPGA的新型可调信号发生器.通过Quartus Ⅱ软件及Verilog HDL编程语言设计LPM_ROM模块定制数据ROM,并通过地址指针读取ROM中不同区域的数据,根据读取数据间隔的不同,实现调整频率功能,该系统可产生正弦波、方波、三角波和锯齿波4种波形信号,并使用嵌入式逻辑分析仪对产生的不同波形信号进行实时测试,实验证明,该可调信号发生器系统软件模拟数据和理论定制波形相吻合.     

时延网络控制系统控制方法研究综述

本文介绍了网络控制系统的基本概念,分析了网络控制系统的优缺点,并主要针对网路控制系统中的时延问题,论述了6种时延网络控制系统控制方法:增广状态离散时间模型法、缓冲队列法、摄动法、随机最优控制方法、鲁棒控制方法、模糊逻辑调节法.本文对6种控制方法各自的特点和适用范围进行了较为详细地讨论,并对各自的优缺点进行了对比分析,对进一步研究适合于时延网络控制系统自身特点的控制方法进行了展望.本文研究的内容是当今控制领域研究的热点问题之一,无论对网络控制系统的研究与应用,还是对网络控制系统中时延问题的解决都具有一定的意义和参考价值.     

Compensation strategies for shunt active-filter control

Compensation strategies for control of shunt active filters are compared in the paper. It is shown that the strategy based on unity-power factor control is appropriate when the supply voltage waveform of the plant where the active filter is connected shows significant distortion. As voltage distortion increases, this strategy provides compensated line current having lower harmonic distortion and RMS value with respect to the strategy generally used. This contributes to diminish the current and voltage distortion in networks. The unity-power factor compensation strategy conditions the current flowing in the plant where compensation is realized to fit the voltage waveform, thus reaching a unity power factor. Hence, the line current RMS value is minimum. The comparison of the strategies is performed by both Monte Carlo and ATP simulation     

Dual closed-loops current controller for a 4-leg shunt APF based on repetitive control

ABSTRACT

Current repetitive control strategy for a 4-leg APF is usually of a poor speed in responding to the drastic changes in load harmonic profile. In this paper, a dual closed-loop current controller composed of a repetitive control-based outer loop and a PI-based inner loop is proposed to improve the performance of a 4-leg APF, with a focus on response speed and harmonic current compensation gain. The principle of the dual loop controller is explained in detail, and the stability of the system is analysed thoroughly. To further decrease the inherent time delay associated with the PWM strategy, a zero-sequence-voltage-based PWM strategy is proposed to solve the complexity in the implementation of 3D-SVPWM methods. By formulating the relationship between the duty ratio of the neutral leg control pulse and the zero-sequence-component of the reference voltages, the duty ratios of the other three legs can be calculated conveniently. The simulation and lab experiment results are provided to verify the correctness and effectiveness of the proposed dual closed-loop current controller and the zero-sequence-voltage-based PWM strategy.     

A four-switch shunt active filter based on one cycle control for compensating non-linear loads

ABSTRACT

This paper introduces a Four-Switch Three-Phase Shunt Active Power Filter (FSTP-APF) based on One Cycle Control (OCC) technique for compensating the currents of three phase non-linear loads. The power stage of FSTP-APF uses only four semiconducting switches which leads to reduce the overall cost of APF. The proposed technique retains the advantages of the conventional OCC, such as no reference current calculation, no need for using Phase-Locked Loop (PLL), very simple control circuit and constant switching frequency. In addition, the modification reduces the number of semiconductor switches, reduces the filter output inductances, reducing the number of sensors to only four sensors, two of them for measuring supply currents and the others for measuring DC-link voltages, and the control algorithm becomes simpler. The feasibility and performance of the proposed technique are demonstrated through the simulation and experimental verifications.     

Finite control set predictive control of shunt hybrid power filter

This paper proposes a finite control set predictive control (FCS-PC) scheme for the shunt hybrid power filter (SHPF) to reduce the power loss while maintaining satisfactory power quality at the utility’s grid terminals. By means of the instantaneous power theory, the controller for the proposed method can generate the reference voltage for the SHPF voltage source inverter (VSI) for the future sampling time. Therefore, during a sampling time, the vector of the reference voltage is compared with the finite number of voltage vectors existent in the VSI to select the vector that best fits the cost function of the controller. The proposed method, compared with the conventional pulse width modulation (PWM) carrier method, has the capability of suppressing similarly the harmonic currents at grid terminals and controlling VSI DC-link voltage while maintaining low switching frequencies in the devices. This method shows simplicity in digital implementation because it does not need a PWM block to obtain the VSI gating signals. In addition, a comparison of the proposed FCS-PC method with the conventional carrier-based PWM method is presented and discussed. Parameter errors in the controller are studied and their effects on system performance are explained. The effectiveness of the proposed method is demonstrated with simulation and experimental results during steady-state operation and transient response of the system.     

基于MAX8515并联稳压器的Li+电池充电器应用

由于Li+电池充电器的充电过程会持续一个小时甚至更长的时间,利用实际负载(即电池)对充电器进行测试将非常耗时。文中介绍了一种简单的Li+电池仿真方法,与采用实际电池进行测试相比,这种方法能够更加方便地测试Li+电池充电器。     

Passive vibration control via electromagnetic shunt damping

This work will present a new type of passive vibration control technique based on the concept of electromagnetic shunt damping. The proposed technique is similar to piezoelectric shunt damping, as an appropriately designed impedance is shunted across the terminals of the transducer. Theoretical and experimental results are presented for a simple electromagnetic mass spring damper system.     

Three-phase four-wire shunt active filter control strategies

This paper describes a three-phase four-wire shunt active power filter using a conventional three-leg converter, without the need of power supply at DC bus. Two approaches have been developed to control the active filter. Both control strategies consider harmonics and zero sequence components in the voltage and current simultaneously. The first one provides constant power and the second one sinusoidal current to the source, even under unbalanced voltage conditions. Simulation results from a complete model of shunt active filter are presented to validate and compare the control strategies     

基于改善相关性的混沌控制

通过改善混沌信号的相关性,离散混沌系统能以较快的速度收敛到它的平衡点或多周期轨道,文中给出了数学分析,和以Henon和耦合映象格子为例的仿真实验.     

模糊控制下的混沌跳频系统的同步

针对混沌信号的伪随机性和易于产生等特点，以改进的Logistic映射为例，用混沌序列取代跳频通信中的跳频码，给出了混沌跳频序列的神经网络实现；提出了用模糊控制的方法产生模糊随机序列，并以此控制混沌跳频系统的同步。计算机仿真结果表明，此方法是可行的，能达到良好的同步。     

Power control algorithm for MMSE receiver based CDMA systems

In this paper, a fully distributed power control algorithm (PCA) based on the minimum mean-squared error (MMSE) receiver is introduced. We study the convergence of the signal to interference plus noise ratio (SINR) and the total transmitted power and we compare, in terms of the capacity, the performance of a system in which the proposed PCA has been implemented and compared with a system with perfect power control. We show that capacity improvement of the order of 20% is obtained by using the proposed PCA     

CHAOTIC CONTROL OF NONLINEAR SYSTEMS BASED ON IMPROVED CORRELATIVITY

Chaotic sequences are basically ergodic random esquences.By improving correlativity of a chaotic signal,the chaotic dynamic system can be controlled to converge to its equilibrium point and,more significantly,to its multi-periodic orbits.Mathematical theory analysis is carried out and some computer simulation results are provided to support such controllability of the chaotic Henon system and the discrete coupled map lattice.