The stability of a chaotic PWM boost converter

A novel chaotic pulse‐width‐modulation (PWM) boost converter has been previously proposed to reduce electromagnetic interference (EMI) in DC–DC converters, where the circuit design and simulations have been conducted, but the problems such as the mean value estimation of state variables for circuit parameter design, the ripple estimation of the input current and the stability analysis have been remained to be addressed in this paper. Here, a mean value estimation method is first proposed, which is used to estimate the mean values of state variables of chaotic PWM boost converters for facilitating the circuit parameter design and selection of circuit components. Although ripples are slightly increased, caused by adopting chaotic carriers, the DC–DC converter with reduced EMI is still stable under the chaotic PWM control. This work provides a theoretic verification of the effectiveness and practicability of the proposed chaotic PWM DC–DC converters. Copyright © 2010 John Wiley & Sons, Ltd.     

电压型PWM整流器故障诊断方法综述

PWM整流器因其具备网侧单位功率因数,能量双向流动等特点在变频调速得到广泛应用,同时也成为变频系统故障多发环节,为减少故障对工业生产的不利影响,其故障诊断研究工作得到了极大的重视,本文对PWM整流器开关管主要故障之一的开路故障目前的诊断方法进行了总结,从故障特征向量的提取和故障的识别、定位方法的角度进行了分类,介绍了各故障诊断方法的原理,对各诊断方法的适用范围、可靠性进行了对比,指出了PWM整流器故障诊断和故障预警今后的研究方向和趋势。     

三相电压型PWM整流的新型直接功率控制

介绍了三相电压型PWM整流器的数学模型,以及传统直接功率控制的基本原理和系统组成,分析了其所采用的开关表存在的不足。提出了一种新的直接功率控制方法,该方法采用新的开关表,功率内环采用简单的PI算法,省去两滞环比较器,易于实现。系统在Simulink下的仿真结果表明,与传统直接功率控制相比,该方法可以得到更高的功率因数、更低的输出直流纹波系数。     

Improved control‐to‐output characteristics of a PWM buck‐boost converter

An indirect control variable for improving the control‐to‐output characteristics of a Pulse Width Modulation (PWM) buck‐boost converter is introduced in this letter. The voltage gain and the small‐signal model of the buck‐boost converter are reviewed. The actual voltage command at one input of the PWM comparator is from the proposed indirect control variable and the peak value of the high‐frequency PWM carrier. The resulted voltage gain function appears proportional to this indirect control command. Also the dependence of the DC gain of the control‐to‐output transfer function on the duty cycle is eliminated. Experimental results conform well to the theoretical analysis. Copyright © 2010 John Wiley & Sons, Ltd.     

三相逆变器统—PWM实现方法研究

在3相逆变器中获得普遍应用的脉宽调制方式是正弦波脉宽调制(SPWM)和空间矢量脉宽调制(SVPWM).根据SVPWM和载波PWM的内在关系,将SPWM、各种连续和不连续SVPWM方法统一于一个显性调制函数表达式中,从而提出了基于载波的统一PWM方法.所建立的统一PWM调制函数既简单又直观,是进行PWM逆变器仿真分析的有效工具,特别是在此基础上提出了一种统一PWM快速算法.该算法直接利用三相参考电压瞬时值计算PWM信号的开关状态切换时间,不需进行坐标变换、三角函数运算、扇区判断和有效矢量作用时间的计算, 更易于SPWM和各种SVPWM方法的数字化实现.最后,对各种PWM方法的电压谐波特性进行了对比分析.仿真和实验结果证明了统一PWM实现方法的正确有效性.     

三相PWM高频整流器主电路参数选择

介绍了一种常用的三相PWM高频整流器单位功率因数时主电路参数的设计方法，给出了设计实例，并基于MAT－LAB领导具软件对整流和逆变2种运行状态进行了仿真研究，结果表明所选择的参数是正确的。     

基于滞环空间矢量三相PWM整流器的研究

为了提高三相PWM整流器的电流跟踪性能,减少开关频率及开关损耗,在研究滞环电流控制方法以及空间矢量控制方法的基础上,提出了改进的空间电压矢量控制方法.该方法通过检测电流误差矢量与参考电压矢量的空间分布给出最佳的电压矢量切换,使电流误差控制在滞环宽度以内;采用空间电压矢量消除相间影响,并且实现简单,无需复杂的矢量变换.仿真及实验结果验证了所提方法的可行性.     

三相PWM整流器电路谐振过电压分析及预防

在三相6开关电压型PWM整流器电路的实际应用中,会发生过电压导致击穿器件绝缘的现象,而目前业界对这种现象研究较少.从新的理论机理分析,发现整流器电路进线阻抗不匹配以及电路的寄生电容电感,这两个因素引发的电路谐振是引起瞬态过电压的主要原因.基于此机理之上,针对性地提出了实用有效的预防方法,经过较多的实际现场验证,证明其对...     

Design of a linearization model for three-phase PWM rectifiers for electrochemical machining

Electrochemical machining (ECM) is a processing method for metals that uses a DC power supply and flowing electrolyte. In some cases, discharge occurs during ECM when the gap between the electrode and workpiece, whose distance is rather small, is filled with hydrogen generated via electrolysis. We attempt to utilize a DC inductor placed between the DC supply and the ECM load in order to limit di/dt of the short or discharge current, which damages both the electrode and workpiece. When the output current surges, that is, when discharge occurs, the output voltage is suppressed by the DC inductance. In this paper, we propose a method for designing a PWM rectifier to reduce the discharge current, establish a linear approximation model for use in the PWM rectifier, describe a control method of the PWM rectifier, and demonstrate the efficacy of the model via simulations and experiments.     

基于滞环电流控制三相整流器的开关频率分析与仿真

通过数学模型对滞环控制三相整流器的开关频率进行了分析,得出开关频率与电感值和滞环宽度的关系,并在Matlab／Simulink环境下进行了仿真,仿真结果验证了分析结论。     

基于低开关损耗滞环控制三相整流器的研究

为了减少三相PWM整流器的开关频率及开关损耗,在研究滞环电流控制方法以及空间矢量控制方法的基础上,提出了改进的空间电压矢量控制方法。该方法通过检测电流误差矢量与参考电压矢量的空间分布给出最佳的电压矢量切换,使电流误差控制在滞环宽度以内;采用空间电压矢量消除相间影响,并且实现简单,无需复杂的矢量变换。仿真及实验结果验证了所提方法的可行性。     

一种新型的高效率Boost PWM变换器的研究

传统的BoostZVTPWM变换器的主开关管实现了软开关 ,但是辅助开关管是在硬开关下关断。因此 ,变换器的效率低。提出了一种新型的BoostZVTPWM变换器 ,详细分析它的工作原理及实现软开关的条件。实验结果证明了所提出的Boost变换器的有源开关管和二极管均实现了软开关 ,并且在满载时效率可达到 94 %左右。新型的BoostZVTPWM变换器的思想也可以扩展到其它的基本变换器拓扑中得到新型零电压转换PWM变换器     

Mathematical modelling of a 3 -phase to single -phase cycloinverter

The paper outlines the operating principles of a 3 -phase to single -phase cycloinverter, as used in heating and melting applications, and presents a digital computer model on which performance predictions may be based. Ideal power switches, an input filter and a compensated heating load are assumed in formulating an initial set of state -variable equations which are valid when all the switching devices are conducting. Connection matrix techniques are then used to generate the mesh equations relevant to the continually changing pattern of the switching devices, leading to a very versatile simulation program. Experimental results from a laboratory -scale unit are presented for different output power levels, and these are compared with corresponding computed results to illustrate the close similarity that exists.     

基于改进滞环控制技术三相整流器的研究

为了减少三相PWM整流器的开关频率及开关损耗,在研究滞环电流控制方法以及空间矢量控制方法的基础上,提出了改进的滞环电流控制方法。该方法通过检测电流误差矢量与参考电压矢量的空间分布给出最佳的电压矢量切换,使电流误差控制在滞环宽度以内;采用空间电压矢量消除相问影响,并且实现简单,无需复杂的矢量变换。仿真及实验结果验证了所提方法的可行性。     

Analysis of a novel four-level DC/DC boost converter

In this paper, novel two-quadrant buck/boost and one-quadrant boost four-level DC/DC power converters are introduced. The primary application for these converters is that of interfacing a low-voltage DC source, such as a fuel cell or battery, to a high-voltage four-level inverter. One important feature of the four-level DC/DC power converters proposed is the ability to perform the power conversion and balance the inverter capacitor voltages simultaneously. With the capacitor voltage balancing, it is possible to obtain the full voltage from the inverter. For the boost converter, the steady-state and nonlinear average-value (NLAM) models are developed. The NLAM is verified against a detailed simulation of a four-level converter/inverter drive system. The proposed converter is experimentally verified using an 18 kW converter/inverter system     

基于合成中矢量的三电平PWM整流器中点平衡新方法

通过分析各种矢量对三相三电平PWM整流器中点电位的影响,提出了一种基于合成中矢量的新的5段式矢量调制算法.采用Matlab对新型5段式和传统7段式三电平PWM整流系统进行了对比仿真.结果表明,该法从中矢量入手,有效地解决了在小输出滤波电容情况下,PWM整流器瞬态过程中的中点电位不平衡问题.     

Motor performance investigation of an indirect matrix converter with a reactor‐free boost converter

This paper describes a three‐phase power converter which utilizes the neutral point of an induction motor and demonstrates the performance of the motor using the proposed method under various operating conditions. Several motor test results, such as the speed–torque characteristic, the torque impact, and the acceleration–deceleration characteristic, are included to confirm the performance of the induction motor. The structure of the proposed circuit consists primarily of an AC/AC converter [indirect matrix converter (IMC)] and a boost converter connected to the neutral point of the induction motor. In addition, this paper also proposes a method to reduce the ripple found in the battery current. Several experimental results show that the motor works well, and even the leakage inductance is utilized in the boost converter. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

A frequency approach for current loop modeling with a PWM converter

A new method based on a frequency approach is used to model a DC permanent magnet actuator driven by a pulsewidth modulated amplifier as a transfer function. This paper investigates two carriers used in industrial applications with analog or digital control. The accurate model presented takes into account the supply amplifier with the motor dynamics and includes the input control voltage sampling effect. Advantages and limitations of both carriers and control signals are discussed, and information about harmonic angles, magnitudes, and distortion are provided. The validation of the pulsewidth modulated model is carried out through simulations and experiments of both open and closed current loop systems with the effect of current ripple     

Steady‐state analysis of a novel ZVT interleaved boost converter

In this paper, a novel soft‐switched interleaved boost converter composed of two‐cell boost conversion units and an auxiliary circuit is proposed and investigated. The proposed auxiliary circuit is implemented using only one auxiliary switch and a minimum number of passive components without an effective increase in the cost and the complexity of the converter. The main advantage of this auxiliary circuit is that it not only provides zero‐voltage‐transition (ZVT) for the main switches but also provides soft switching for the auxiliary switch and diodes. Though all semiconductor devices operate under soft switching, they do not have any additional voltage and current stresses. The proposed converter operates successfully in soft‐switching operation mode for a wide range of input voltage level and the load. In addition, it has advantages such as fewer structure complications, lower cost and ease of control. Since the two‐cell interleaved boost units are identical, operational analysis and design for the converter module become quite simple. In this study, the detailed steady‐state theoretical analysis of the proposed converter is presented, which is verified exactly by simulation and experiments carried out on a prototype of a 120 W and 50 kHz/cell interleaved boost converter. The practical results confirm the results obtained from theoretical analysis. Copyright © 2010 John Wiley & Sons, Ltd.     

紧凑而可靠的新型126kV三相共筒型GIS

笔者介绍了一种紧凑而可靠的新型126 kV三相共筒型GIS,同时对产品的成本进行了分析。分析结果表明,新设计在基础材料成本、运输、运行、维护成本上均有一定的优势。