A family of single-phase direct-link uninterruptible power supply with unity power factor and sinusoidal input current

In this paper, a family of single-phase direct-link uninterruptible power supply (DLUPS) is proposed to achieve sinusoidal input current waveforms, unity power factors without current sensors and conduct single-stage voltage conversion in normal, backup and charging modes. The design considerations concerning the determination of the power circuit elements are also given for reference. Finally, some examples of simulated and experimental results are presented.     

A control method to realize sinusoidal input and output current waveforms for matrix converters based on PWM

A matrix converter (MC) is a three‐phase AC‐to‐AC direct converter without any energy storage requirement. It is expected to be a next‐generation converter by reason of possibilities of small size and high efficiency. At present, there are some problems preventing it from being used practically. One of the problems is the distortion in the input current. The control methods proposed so far have not realized sufficient reduction of the input current harmonics compared with conventional PWM rectifiers. As a solution to these problems, many approaches have been proposed. In the present paper, an improved PWM method that can achieve both sinusoidal input and output currents simultaneously is considered. In this method, the MC is treated as a controlled voltage source viewed from the load side. On the other hand, it is treated as a controlled current source viewed from the line side. The proposed control method is based on the mathematical expression of the function of the PWM operation of MC. To improve the input current waveform, two line‐to‐line voltages of the three‐phase line are used to control the output current. The output duty ratio of the two line‐to‐line voltages is utilized to improve the input current waveform without affecting the controllability of the output current. In addition, the compensation of the variations in the line voltage and the output current are introduced. In this way, the proposed method can realize the sinusoidal input and output currents. The effectiveness of the proposed control method is confirmed by some experimental results employing a laboratory prototype. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(1): 66–76, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20242     

A sinusoidal PAM-PWM inverter

A new strategy, using both PAM (pulse amplitude modulation) and PWM (pulsewidth modulation) in combination for a power inverter is described. The output waveforms in the proposed PAM-PWM inverter are investigated both theoretically and experimentally. The line-to-line voltage waveform includes the fundamental component and the sidebands of the carrier frequency. Lower-order harmonics are not included in the output waveform. The amplitude of the fundamental component increases 15 percent more than that of a conventional sine-wave inverter. Since each inverter arm does not operate during two-thirds of the period, the heat generated in the devices is reduced, i.e., the size of the inverter system can be minimized because of the reduction in the heat dissipating equipment.     

Initial value compensation with additional input considering optimization of control input

This paper presents a novel method of initial value compensation (IVC) with additional input by considering the optimization of control input. IVC has been used to improve the control performance of various control systems with different initial values. Essential subjects, however, have still remained: in the conventional IVC approaches, the increases in the amplitude and number of high‐frequency components of the control input that accompany an increase in the control bandwidth could not be avoided. In this research, therefore, an optimization approach for control input is applied under the constraints of the conventional IVC approach. The effectiveness of the proposed approach has been verified by numerical simulations and experiments using a prototype. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(2): 63‐73, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21026     

Design criteria for high-frequency RC-active sinusoidal oscillators

High-frequency RC-active sinusoidal oscillators using two op amps are surveyed from a unified viewpoint. Information about their performance is obtained using linear and non-linear approaches. As a consequence of this analysis, two main criteria are proposed to optimize these systems and to select the best configuration for a given application. the first criterion is related to the feasibility of obtaining an oscillation frequency independent of the op amps used in the design. the second criterion is connected with the level of harmonic distortion present in the signal. Experimental measurements obtained agree closely with the theoretical analysis carried out.     

可逆变流器正弦滞环宽度控制方法

滞环控制方法具有动态响应速度快和电路结构简单的优点,该方法获得了广泛的应用和发展。从改善系统的输入电流谐波总畸变率THD（Total Harmonic Distortion）角度,提出一种改进的正弦滞环宽度控制方法,可有效减小脉宽调制（PWM）可逆变流器系统的THD。在PWM可逆变流器系统状态空间模型的基础上利用Psim仿真软件进行分析。和固定滞环宽度控制方法相比．应用改进的正弦滞环宽度控制方法,系统具有更小的THD。快速傅里叶变换结果表明,应用改进的正弦滞环宽度控制方法．系统具有更小的谐波含量。     

Electronically controlled multiphase sinusoidal oscillators using current amplifiers

A novel current‐mode multiphase oscillator topology is introduced in this letter. This is realized by employing current amplifiers and only grounded capacitors. Attractive characteristics offered by the new topology are the electronic adjustment of the oscillation frequency, the absence of passive resistors, and the requirement of only grounded capacitors. Comparison with the corresponding already published current follower based structure shows that the proposed topology has better performance in terms of the number of required active elements, the employment of passive resistors, and the ability for electronic adjustment of the oscillation frequency. Copyright © 2008 John Wiley & Sons, Ltd.     

四相开关磁阻电机带直流偏置正弦激励特性研究

针对四相开关磁阻电机（SRM）传统方波励磁转矩脉动大的问题,提出了一种单极性正弦励磁控制方法。首先建立了两相旋转坐标系下四相SRM的数学模型,分析了带直流偏置正弦励磁时瞬时转矩,结果表明转矩和iq分量成正比并且转矩不含三相SRM单极性正弦励磁时的磁阻转矩分量。然后研究了在两相旋转坐标系下对电流分量的控制方法,转矩分量采用SPWM控制,励磁分量采用电流滞环跟踪控制。最后对本文提出的控制方法通过有限元进行仿真分析并给出实验验证。实验结果表明在该种控制方式下SRM的转矩脉动小于传统方波励磁的转矩脉动。     

New sinusoidal oscillator configurations using operational transresistance amplifier

The objective of this brief is to introduce four new structures of electronically tunable sinusoidal oscillators (SOs) designed using operational transresistance amplifier (OTRA). Each of the proposed SO consists of forward path derived from a generic structure along with one/two OTRA-based resistive gain stages or differentiator in its feedback path. All the proposed SOs enjoy independent tuning of the frequency of oscillation (FO) through resistors without affecting the condition of oscillation (CO). Further, all topologies are found to exhibit low f_o sensitivities at all frequencies with respect to circuit parameters, and the second topology is capable of achieving very low frequencies (VLFs) using less RC component spread and provides linear tuning too. The fourth circuit provides quadrature output. The proposed SOs have been successfully implemented and verified in 180-nm CMOS technology node using ADE (analog design environment) tool Cadence Virtuoso. Both prelayout and postlayout simulation results have been included. To assess the oscillator prefabrication performances, Monte Carlo and process-voltage-temperature (PVT) analyses have been performed. The total harmonic distortion (THD) is observed to be less than 3.5%.     

Non-adaptive second-order generalized integrator for sinusoidal parameters estimation

In this paper, a simple method for frequency, amplitude and phase estimation of a single sinusoidal signal is proposed. The approach described herein uses an orthogonal signals generator based on a Second-Order Generalized Integrator (SOGI). The frequency, amplitude and phase are estimated on the base of straightforward explicit formulas without any adaption of SOGI parameters. The method is implemented as a dynamic third- or fourth-order system according to specified cost function to be minimized. In case of highly corrupted signal a double-SOGI scheme can be used to further improve the filtering capabilities. The effectiveness of the proposed algorithm is demonstrated through simulated experiments and comparisons with existing methods.     

正弦电压馈电的直线感应发射器加速特性

为了给直线感应发射器实验平台的设计与实验提供前期理论参考,介绍了基于网孔矩阵法的直线感应发射器集中参数电路等效模型及其数值算法,对三相正弦电压激励下的直线感应发射器加速特性与电压初始相位、幅值、频率的关系进行了仿真分析。仿真结果表明,对于结构参数确定的直线感应发射器,有最佳的电源电压初始相位、幅值和频率对应关系,可以实现其加速性能的充分发挥。     

A novel approach for a sinusoidal output inverter

Minimization of the total harmonic distortion (THD) at the output of an inverter is essential to reach the ideal case, i.e. a pure sinusoidal. So far, very intensive studies about this topic have been carried out. In this study, a fully rectified version of a sinusoidal voltage waveform at an utility amplitude and frequency obtained from a well-known buck–boost regulator has been converted to a sinusoidal AC voltage waveform with a simple inverter operation. The purpose of this innovative circuit is to generate an approximate sinusoidal voltage waveform with a quite low THD at the inverter output without invoking the harmonic elimination techniques. Since distortions in the AC link voltage in this circuit fully depend on how well the capacitor current is regulated to its reference, the value of the load current is a critical component in this regulation.     

Quick regulation of sinusoidal output current in PWMconverter-inverter system

An induction motor drive system composed of a current output-type power converter and a current source inverter with sinusoidal input and output voltage/current is presented. Pulsewidth modulation (PWM) strategies with GTOs are applied to the converter and the inverter sections from the point of view of reduction of the current harmonics and suppression of the motor torque pulsations. A simple method for quick regulation of the AC output current amplitude is presented and applied to the PWM inverter section. To demonstrate the improvement in the current response of the inverter, a slip frequency/current regulation of an induction motor is considered. The experimental results of steady-state and dynamic operations of the motor are shown. The merits and demerits of this control method are discussed     

基于正弦函数模型的电压暂降检测算法

为解决电压暂降问题,动态补偿技术是其最终途径,而准确检测出电压暂降的主要特征量是电压暂降补偿的前提.并且检测装置需采取滤波处理措施以减少非基频信号的影响.将基于正弦函数模型的算法应用于电压暂降检测方法,采用图基低通数字滤波器进行数字滤波,且对其检测结果进行分析,并提出了一种基于正弦函数模型的改进方法.仿真结果证明了该方法的有效性.