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。     

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.     

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。     

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...     

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。     

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。     

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。     

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.     

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     

介绍一种三相交流电源缺相、错相检测与保护

三相交流电被广泛地应用在工农业生产中 ,发电和输配电一般都采用三相制。如果发生某一相断线或错相连接 ,便会产生缺相或错相的不正常运行状态。三相电源缺相或错相的长期运行 ,轻则导致系统工作不正常 ,重则烧毁用电设备。因此三相交流电源的缺相或错相保护一直是电力系统和供电系统研究和探讨的重点。本文介绍的三相交流电源缺相和错相保护装置 ,改变了传统的应用互感器的检测方法 ,因而使线路简单方便 ,提高了缺相和错相保护的可靠性 ,性价比较高。本文介绍的装置 ,如附图所示 ,装置采用了陕西高科电力电子有限责任公司生产的TH2 2 1厚…     

A novel slip‐power recovery system using a PWM boost rectifier

A novel compact slip‐power recovery system having sinusoidal rotor currents is proposed. In this system, a PWM boost rectifier is used as a substitute for a diode rectifier and a boost chopper in a conventional compact slip‐power recovery system. The conventional compact system has the disadvantage that it has a rectangular rotor current, and a motor torque with large ripple, because a diode rectifier remains in the system. Also, the rotor current cannot reach the current reference value near the synchronous speed, because the voltage drop caused by the resistance of the semiconductor devices and so on cannot be neglected when the rotor voltage becomes smaller near the synchronous speed. The use of the system proposed in this paper has solved these problems. The effectiveness of the proposed system was verified through computer simulations and experiments. As a result, the proposed system brings the sinusoidal rotor current, the small torque ripple, and wide controllable range near the synchronous speed. © 2002 Scripta Technica, Electr Eng Jpn, 139(2): 52–60, 2002; DOI 10.1002/eej.10012     

Detection of initiation of a bifurcation phenomenon in the dynamics of a PWM converter

The possibility of diagnosing bifurcation phenomena in the dynamics of a PWM converter by the symbolic and the spectral methods is explored. The investigation is carried out using an experimental DC PWM drive setup.     

Voltage control of super high-speed reluctance generator systemwith a PWM voltage source converter

A voltage control system for a reluctance generator with a PWM voltage source converter is proposed. A phasor diagram of the generator is developed by introducing an iron loss conductance. A practical method for achieving optimal efficiency over the complete operating range is suggested. It is based on the optimal-efficiency current angle tracking by adjusting the voltage ratio of AC-to-DC voltage. The performance of the system is investigated by using the new phasor diagram. It is shown that a system with a PWM converter has wider operating range than one with a self-commutated six-pulse converter. The proposed control system is realized on a laboratory prototype, where control routines are mainly implemented by a 16 b single-board microcomputer. Experimental results show that 10% or more improvement compared with that of the system fed by a six-pulse converter is obtained at half full load     

基于DSP的新型全桥PWM DC/DC变换器研究

提出了一种原边带钳位二极管的移相全桥ZVS DC/DC变换器拓扑,解决了传统的移相全桥ZVSPWM DC/DC变换器整流桥寄生振荡问题,给出了主电路结构,阐述了变换器的工作原理,设计了具有限流保护功能的电压环、限流环控制系统,并采用TMS320LF2407A作为主控芯片,实现了变换器系统的双闭环数字控制,最后进行了实验...     

Comparative evaluation of sliding mode fuzzy controller and PID controller for a boost converter

Nonlinear controllers such as fuzzy controllers and sliding mode controllers have been applied to boost converters because of their nonlinear properties. Although both fuzzy and sliding mode controllers have desirable characteristics, they have disadvantages in practice when applied individually. A sliding mode fuzzy controller is proposed to control boost converters. The sliding mode fuzzy controller combines the advantages of both fuzzy controllers and sliding mode controllers. It also has advantages of its own that are well suited for digital control design and implementation. A sliding mode fuzzy controller is designed and verified with experimental results using a prototype boost converter with a DSP-based digital controller. Experimental results of the boost converter using sliding mode fuzzy control are evaluated in comparison with experimental results using a linear PID and PI controller. The comparison indicates that the sliding mode fuzzy controller is able to obtain the desired transient response under varying operating points without chattering. The startup response using sliding mode fuzzy control is superior to the response using PID and PI control, while the load transient response shows no obvious advantage.     

双开关三相四线PFC电路的研究

提出了一种双开关三相四线功率因数校正拓朴电路,该电路能够提高电力电子装置的功率因数,减少装置对电网的谐波污染,满足或者接近相关的谐波标准;降低三相PFC的复杂性,降低制造成本,达到实用化的要求。本文叙述了该电路拓朴的工作原理和控制方法,最后给出了实验结果,验证该电路的正确性。