A New Analog Controller for Three-Phase Four-Wire Voltage Generation Inverters

This paper introduces a new controller for three-phase four-wire inverters, with the control goal of generating high-quality three-phase output voltages for all sorts of linear/nonlinear and balanced/unbalanced loads. The proposed controller employs a circuit-level decoupling method, and it is implemented by logic circuitry in combination with a control core and a feedback signal processor. Almost all dc–dc control methods can be adapted as the control core, while the feedback signal processor can be implemented by either voltage compensator and/or current compensator. The implementation of the controller is simple and flexible with only logic and analog circuitry needed. Yet, it demonstrated experimentally excellent load handling and source voltage noise rejection ability. The prototype is tested under balanced and unbalanced resistive and nonlinear loads, as well as under extreme load transients. It is also tested with power from a noisy dc input source. In all cases, the prototype demonstrated high-quality output voltages.      

一种新的模拟电压分类器

本文介绍了一种用于比较和分类两个模拟输入电压的新方法，利用该电路作为一个基本单元设计了一个四输入的分类器，同时也提出了一种确定与某一个输出量相对应的输入量地址编码的方法，应用这种方法也可以设计更多输入量的分类器。     

一种新型软开关三相PWM逆变器拓扑的研究

本文提出了一种三相交流谐振环节软开关逆变器的电路拓扑及其控制方法。该拓扑采用正负斜率交替的锯齿载波．使所有功率开关器件的计通集中征锯齿载波的垂直沿处，在此时启动辅助谐振电路，完成功率开关器件的切换。分析软开关动作模式．并对各模式的过渡过程进行数学解析。对系统进行了仿真，仿真结果表明采用该控制方法能实现逆变器功率开关器件的零电压软开关动作。     

A New Phase-shifted Cascade High Voltage Inverter

This paper presents the characteristic and structure of phase-shifted cascade high voltage inverter. The high voltage inverter utilizes fewer power switches and has a balance load, a good linearity between input and output and a perfect control feature.     

A Universal Vector Controller for Four-Quadrant Three-Phase Power Converters

Power factor corrected (PFC) rectifiers, active power filters (APFs), static VAR compensators (STATCOM), and grid-connected inverters (GCI) are indispensable elements in distributed generation power systems. PFC rectifiers are essential for load side harmonic and reactive power correction, APFs can suppress the harmonics generated by nonlinear loads or sources, STATCOMs can control the power flow in the grid, while GCIs are the key elements bridging the renewable energy sources and the power grid. Previous theory and experiments have demonstrated that one-cycle control is capable of controlling all above mentioned three-phase converters, featuring excellent performance, simple circuitry, and low cost. This paper further unifies the control key equations for the previously mentioned converters, which results in a universal solution that realizes all these functions with a same controller. The concept has been verified by a 1-kVA prototype and supported by a series of experimental results     

Selective Harmonic Elimination PWM Control Scheme on a Three-Phase Four-Leg Voltage Source Inverter

A selective harmonic elimination (SHE) control strategy on a three-phase four-leg inverter is reported in this paper. The control signals of the four legs are calculated as follows: 1) control signals of three legs are mathematically expressed using Fourier-based equations on line-to-line basis as conventional SHE technology, which eliminates lower order nontriplen harmonics, and 2) the fourth leg produces the harmonics that are equal to the lower triplen harmonics produced by the other legs. The inverter has almost symmetric three-phase output voltage with unbalanced load because the fourth leg provides a low-impedance path for the triplen harmonics. The switching-to-fundamental frequency ratio is only 13 and 27 (per unit) p.u. for the three legs and the fourth leg in the proposed prototype, which is with the total harmonic distortion of output voltage lower than 4%. Selected solutions for the switching angles are presented and verified by simulation and experimentation in order to confirm the effectiveness of the proposed scheme.     

Trapezoidal Modulating Signal for Three-Phase PWM Inverter

Trapezoidal wave is suitable for the modulating signal of the microcomputer-based pulsewidth modulation (PWM) inverter for the use of motor drives because the switching patterns can be generated by means of on-line computation. The waveform is changed from a rectangular to a triangular wave.     

三相并网逆变器LCL滤波器的简明设计

LCL滤波器以其较好的滤波性能被广泛地用于并网逆变器,但无阻尼时系统产生谐振,给系统的稳定性控制带来困难。文中在建立三相并网逆变器数学模型的基础上,采用基于d,q同步旋转坐标系的电网电压定向控制策略,利用被动阻尼抑制谐振提高了并网逆变器的稳定性能。文中给出了被动阻尼LCL滤波器的详细设计方法,并比较其与单L滤波器的滤波效果,运用Matlab/simulink建立系统模型并进行仿真,实现了单位功率因数并网。     

A Simple Analog Controller for Single-Phase Half-Bridge Rectifier

A simple analog controller is proposed for the single-phase half-bridge pulsewidth modulation rectifier to maintain near unity power factor at the input and balance the voltages across each half of the dc bus. The controller works in the principle of constant-frequency current programmed control. The required gating pulses are generated by comparing the input current with a linear and bipolar carrier without sensing the input voltage. Two voltage controllers and a single reset-integrator are used to generate the carrier. All the necessary control operations are performed without using any phase locked loop, multiplier, and/or divider circuits. Resistor based sensors are used to measure the voltages across two halves of the dc bus and the input current. The controller can be fabricated as a single integrated circuit. The averaged small signal models and all the necessary design equations are provided. The condition of stability against subharmonic oscillation is analyzed. Calculation of switching and conduction losses is presented. The control concept is validated through simulation and also experimentally on an 800-W half-bridge rectifier. Experimental results are presented for ac-dc application, and also for ac-dc-ac application with both linear and nonlinear loads at two different output fundamental frequencies (50 and 60Hz)     

一种电流反馈型三相无刷直流电机控制器

基于经典的闭环反馈控制理论和PWM理论在电机控制中的应用,设计了一种三相无刷直流电机控制器.该电路可实现对三相无刷直流电机的驱动和控制,具有功率电压高、驱动电流大、零点精确等优点,同时具有高边占空比100％可调和过流保护等功能,是一款真正的四象限扭矩电机控制器.     

弥补模拟控制器缺点的数字控制器

新兴的电源控制数字IC缺乏模拟IC中一些很常见的基本特性,如内建栅极驱动和限流特性。数字电源控制器通常只有PWM（脉宽调制）逻辑输出,而离散栅极驱动器很少包括限流功能。此外,多数带保护的FET只能在低频、低端应用中工作。     

高效率三相谐振极逆变器

为优化三相逆变器的性能,提出了一种高效率三相谐振极逆变器.在各相桥臂上增设的辅助谐振电路参与逆变器的换流过程时,桥臂上的各主开关并联的谐振电容的电压能周期性形成零状态,使主开关能完成零电压软切换,而且辅助谐振电路中的各开关器件也能完成零电流软开通和零电压软关断.开关器件实现软切换能降低开关损耗,从而使逆变器实现高效率运行.文中分析了电路的工作流程.3kW样机上的实验结果表明主开关和辅助开关都处于软切换.因此,该拓扑结构对于研发高性能三相逆变器具有借鉴价值.     

模拟电路故障诊断的结点电压灵敏度比值法

在证明线性电路中结点电压变化量比值等于结点电压灵敏度比值的基础上,提出了结点电压灵敏度比值法,通过结点电压变化量比值和结点电压灵敏度比值的比对确定电路的故障元件。理论分析和实验结果表明,该方法算法简单、诊断速度快,在可测点受限条件下具有较高的诊断精度,特别适合大规模线性模拟电路的故障诊断和测试。     

Three-Phase Low-Frequency Commutation Inverter for Renewable Energy Systems

The connection of distributed power sources with the utility grid generally needs an electronic power converter for processing the locally generated power and injecting current into the system. If the source provides a dc voltage, the converter must be able to produce a low-distortion high-power-factor ac current. The same aspects related with the voltage and current distortion produced by nonlinear loads can be considered for the injection of power into the grid. In the absence of a specific standard, this paper takes as a reference the limits for current harmonics given by international standards. The justification for this approach is that, from the resulting line voltage degradation, there is no difference between injected and absorbed currents. This paper presents a three-phase inverter using low-frequency commutation. An auxiliary circuit is added to the inverter topology to reduce the output voltage distortion, thus improving the current waveform. The main advantages of this approach are the minimization of the switching losses and the elimination of the electromagnetic interference, which avoids high-frequency filters necessary in high-frequency commutation inverters     

新型低压无功补偿器的设计

主要介绍了基于ATT7022B和ST-SRC或ST-SRCS-4智能开关的新型无功补偿统。该控制器通过高精度多功能三相电能专用计量芯片ATT7022B实时检测电网的电压、电流、功率因数、无功电流和无功功率,并有CAN总线通信接口。ST-SRC或ST-SRCS-4智能开关可在电压或电流过零点时动作,并可以通过CAN总线接口与和无功补偿控制器进行通信,最终使电容器组按一定的规律进行投切,最终实现无功补偿。     

新型三相谐振直流环节逆变器

为实现三相逆变器的高效率运行,提出了一种新型三相谐振直流环节逆变器拓扑结构,其在直流环节设置了结构简单的辅助谐振电路.分析了电路的工作流程.实验结果表明开关器件实现了软切换,而且逆变器输出电流波形无明显畸变.因此,该逆变器能实现高效率稳定运行.     

自举式三相半桥级联型多电平逆变器

本文提出了一种新型的三相四线制多电平逆变器,它在常规六开关三相全桥逆变输出上,再级联一级半桥,并加入自举电路,负载中线与输入电源正极相连.在纹波跟踪分段式SPWM(Sinusoidal Pulse Width Modulation)调制下,级联的半桥电能由自举电路工作时得到.该电路拓扑结构及其控制方法,减少了多电平逆变的独立直流电源数,提高了逆变输出电压.文章用逐段计算法分析了规则采样SPWM调制法的自举电容的纹波和电流,以及产生的谐波.通过分析和实验表明,自举电容的电容量、充电回路电阻、负载和调制度等,均对自举电容的纹波和电流有影响.     

新型三相谐振极软开关逆变器

为提高三相逆变器的转换效率,提出了一种新型三相谐振极软开关逆变器拓扑结构,通过在每相桥臂上增加结构简单的辅助电路,实现了主开关的零电压软开通和零电流软关断.逆变器主开关采用金属氧化物半导体场效应晶体管（Metal Oxide Semiconductor Field Effect Transistor,MOSFET）或者绝缘栅双极型晶体管（Insulated Gate Bipolar Transistor,IGBT）时,都能实现无损耗切换,解决了MOSFET内部结电容造成的容性开通损耗问题和IGBT拖尾电流造成的关断损耗问题.分析了电路的工作过程,实验结果表明开关器件完成了软切换.因此,该拓扑结构对于提高逆变器的性能具有重要意义.     

Fundamental-Frequency-Modulated Six-Level Diode-Clamped Multilevel Inverter for Three-Phase Stand-Alone Photovoltaic System

This paper presents a fundamental-frequency-modulated diode-clamped multilevel inverter (DCMLI) scheme for a three-phase stand-alone photovoltaic (PV) system. The system consists of five series-connected PV modules, a six-level DCMLI generating fundamental-modulation staircase three-phase output voltages, and a three-phase induction motor as the load. In order to validate the proposed concept, simulation studies and experimental measurements using a small-scale laboratory prototype are also presented. The results show the feasibility of the fundamental frequency switching application in three-phase stand-alone PV power systems.