关于UPS逆变器并联控制技术的研究

文章通过工作实践并结合相关资料分析了最新无互联线逆变器并联控制基本原理,相比较传统的集中控制、主从控制、分散逻辑控制,总结了各种逆变嚣并联控制技术的优缺点,结合模块化UPS逆变器并联控制技术的发展趋势,分析了基于下垂特性的无互联线逆变器并联控制技术,指出无互联线的并联控制技术将成为未来模块化UPS的发展主流。     

用于逆变器并联的电力线通信技术研究

提出了一种逆变器并联的策略，和一般的控制策略不同的是不需要逆变器之间的互联线，而是通过电力线通信来实现负载有功和无功的均分。仿真结果表明这是一种可行的控制方法。     

一种用于提高无线并联逆变器均流性能的控制方法

本文基于传统的无互线逆变器并联下垂法,提出一种用于提高逆变器均流性能的控制方法。同时本文考虑了连线阻抗和逆变器输出阻抗,分析了逆变器并联系统的有功环流和无功环流,本文提出的控制方法可以减小下垂法的频率和幅值的波动幅度,增加系统输出的稳定性,并提高系统的动态和静态环流抑制能力。仿真和实验结果均验证了该方案的良好性能。     

多路太阳能功率变换模块控制策略研究

针对传统的太阳能电池单个功率变换器模块功率不易扩展的问题,设计一种可并联工作的太阳能电池变换器模块,在实际应用过程中,可通过直接改变并联在母线上的模块数调节整个发电系统的功率.设计模块的并联方案,对负载处于临界状态时的控制问题进行分析并提出一种解决方法.对该并联控制方案进行仿真与实际硬件电路并联实验,结果验证了方案的可行性.     

基于功率均分的逆变器并联控制技术

本文介绍了一种基于功率均分控制的无主从独立结构的逆变器并联控制系统。分析了逆变器无功功率与电压幅值、有功功率与电压相位之间的关系，提出了并联控制方案．成功实现了5台3kVA逆变器的并联均流控制。     

现场总线在并联逆变电源系统中的应用

提出将现场CAN总线引用到并联逆变电源系统中的设计理念,对逆变器并联技术进行分析,由此提出一种利用CAN总线实现各逆变单元的通信,最终实现消除各逆变器之间环流的方案。介绍CAN总线的特点,并利用DSP2407A实现逆变器的控制和CAN总线的通信,同时给出CAN总线的软件设计。最后在Matlab平台上对系统进行仿真,仿真实验结果证明:利用CAN总线可以更好地实现该电源系统的稳定性和抗干扰性。     

逆变器无线并联控制方案的设计与实现

首先对逆变器无线并联的原理作了简单的介绍。其次依据逆变器技术指标设计了一种以dsPIC30F3011芯片为核心控制器的无线并联控制方案,结合系统主电路和相关控制原理,给出了该系统的硬件设计和软件设计。最后以两台逆变器并联为研究对象进行实验验证,实验结果表明该控制方案能够达到技术指标的要求并且能够有效地抑制并联系统产生的环流,使输出功率和负载电流得到均分。     

UPS逆变电源的并联控制技术综述

多模块UPS能较灵活地实现对电源系统容量的扩展，为了增加整个电源系统的可靠性，它可以组成冗余并联系统。文中对目前采用的UPS并联连接控制方式和均流控制技术进行了综述。逆变器并联的全数字化控制方案是交流电源领域的发展趋势。     

光伏并网逆变器电压型控制技术研究

本文主要对电压源电压型并网控制技术进行了研究.根据逆变器并联运行中的无功调幅.有功调频的控制原理,将此方法应用到光伏并网逆变器中实现了有功和无功的独立控制.使得逆变器在输出功率上控制更加灵活详细讨论了电压型并网控制算法,并给出了关键模块I_(d)、I_(q)。的计算方法和正弦波合成器的实现过程最后.在Matlab/Simulink中建立了仿真模型,并进行了实验验证.仿真和实验结果表明电压型并网控制方案具有可行性。     

基于无主从式和数字均流的逆变器并联研究

逆变电源的并联对于扩大系统供电容量，提高供电系统的可靠性等具有重要的意义。本文详细分析了逆变器并联的原理，提出了一种采用无主从式方法消除逆变器并联有功环流和采用CAN现场总线消除逆变器并联无功环流的数字均流方案，这种方案可以有效的减少并联系统中逆变器之间的相互影响，提高了并联系统的工作可靠性能。该方案在3kVA逆变器并联系统中得到了成功的运用。     

3C strategy for inverters in parallel operation achieving an equalcurrent distribution

A circular chain control (3C) strategy for inverters in parallel operation is presented in the paper. In the proposed inverter system, all the modules have the same circuit configuration, and each module includes an inner current loop and an outer voltage loop control. A proportional-integral controller is adopted as the inner current loop controller to expedite the dynamic response, while an H^∞ robust controller is adopted to reach the robustness of the multimodule inverter system and to reduce possible interactive effects among inverters. With the 3C strategy, the modules are in circular chain connection and each module has an inner current loop control to track the inductor current of its previous module, achieving an equal current distribution. Simulation results of two-module and a three-module inverter systems with different kinds of loads and with modular discrepancy have demonstrated the feasibility of the proposed control scheme. Hardware measurements are also presented to verify the theoretical discussion     

逆变电源并联技术的现状与发展

分析了逆变电源并联的基本原理，介绍了并联技术发展过程中出现的几种控制方案，并针对各种并联方案的优缺点讨论了今后逆变电源的发展趋势。     

Multilevel inverter by cascading industrial VSI

In this paper, the modularity concept applied to medium-voltage adjustable speed drives is addressed. First, the single-phase cascaded voltage-source inverter that uses series connection of insulated gate bipolar transistor (IGBT) H-bridge modules with isolated DC buses is presented. Next, a novel three-phase cascaded voltage-source inverter that uses three IGBT triphase inverter modules along with an output transformer to obtain a 3-p.u. multilevel output voltage is introduced. The system yields in high-quality multistep voltage with up to four levels and low dv/dt, balanced operation of the inverter modules, each supplying a third of the motor rated kVA. The concept of using cascaded inverters is further extended to a new modular motor-modular inverter system where the motor winding connections are reconnected into several three-phase groups, either six-lead or 12-lead connection according to the voltage level, each powered by a standard triphase IGBT inverter module. Thus, a high fault tolerance is being achieved and the output transformer requirement is eliminated. A staggered space-vector modulation technique applicable to three-phase cascaded voltage-source inverter topologies is also demonstrated. Both computer simulations and experimental tests demonstrate the feasibility of the systems.     

Modular design of soft-switching circuits for two-level and three-level inverters

This paper presents a negative-bus auxiliary resonant circuit (NBARC) and novel mirror symmetrical pair of resonant link modules for soft commutation of two-level and three-level inverters. The NBARC topology reduces the power device counts and requires low device power ratings. While the basic NBARC resonant circuit is conceived and analyzed for zero-voltage switching (ZVS) of two-level inverters, the topology and modular design approach are extended to form a pinched-link resonant stage of ZVS for three-level inverters using mirror-symmetrical pair of resonant modules. The circuit is also designed as an optional module that can be attached to a standard inverter bridge and converted into a soft-switched inverter. Experimental results verify our circuit analysis and implementation.     

基于环流反馈的逆变器并联系统仿真分析

对于逆变器并联系统,各模块输出电压之间如若存在幅度和相位上的差异,势必会产生在模块间流动的环流。文中在逆变器并联系统环流产生机理分析的基础上,对是否加入环流反馈时系统的阻抗和稳定性进行了分析,证明采用环流反馈可以增大系统环流阻抗,在保持输出电压不变的前提下有效地减小了环流,最后通过Simulink仿真证明此方式的有效性。     

A High-Frequency Resonant Inverter Using Current-Vector Control Scheme and Its Performance Evaluations

The authors introduce a new configuration of resonant-type high-frequency inverter having inherent fast control response of the output power and variable-voltage variable-frequency (VVVF) capability. The circuit is composed of a parallel combination of two series-resonant inverters with common input and output terminals. Both inverter units are operated at synchronous frequency and with an adjustable phase difference from 0° to 180°, allowing control of the output power from full to null power, respectively. Operation of this inverter is explained and computer-simulated operating waveforms and characteristic curves are shown in terms of normalized control variables and circuit parameters. A prototype inverter using Power MOSFET modules has been originally tested with a high-frequency induction heating and melting load to demonstrate experimentally the proposed control principle and the steady-state inverter performances under parallel tuned load conditions.     

Continuous and discrete variable-structure controls for parallel three-phase boost rectifier

We describe three nonlinear control schemes for a parallel three-phase boost rectifier consisting of two modules. The basic idea, however, can be extended to a system with N modules. All of the control schemes are developed in a synchronous frame. Moreover, each of the closed-loop power-converter modules operates asynchronously without any communication with the other module. Based on the dynamical equations of the parallel converter, we find that independent control of both of the modules on the DQ axes is not necessary and possible. Consequently, we develop control schemes that stabilize the dq axes and limit the zero-axis disturbance by preventing the flow of the pure zero-sequence current. One of the control schemes is developed purely in the discrete domain. It combines the space-vector modulation scheme with a variable-structure control, thereby keeping the switching frequency constant and achieving satisfactory dynamic performance. The performances of the other control schemes are also satisfactory.     

A grid-interfacing power quality compensator for three-phase three-wire microgrid applications

This paper proposes a grid-interfacing power quality compensator for three-phase three-wire microgrid applications with consideration of both the power quality of the microgrid and the quality of currents flowing between the microgrid and utility system. It is proposed that two inverters connected in shunt and series are used for each distributed generation (DG) system in the microgrid. In each inverter, both positive- and negative-sequence components are controlled to compensate for the effects caused by the unbalanced utility grid voltages. Specifically, the shunt inverter is controlled to ensure balanced voltages within the microgrid and to regulate power dispatches among parallel-connected DG systems, while the series inverter balances the line currents by injecting appropriate voltage components. A current-limiting algorithm is also proposed and integrated within the inverter control schemes to protect the microgrid from large fault currents during utility voltage sags. The proposed compensator has been tested in simulations and experimentally using a laboratory hardware prototype.     

A power-efficient wide-range phase-locked loop

This work presents a phase-locked loop for clock generation that consists of a phase/frequency detector, charge pump, loop filter, range-programmable voltage-controlled ring oscillator, and programmable divider. The phase/frequency detector and charge pump are designed to reduce the dead zone and charge sharing for enhancing the locking performance, respectively. In the design of the range-programmable voltage-controlled oscillator, the original inverter ring of a delay line is divided into several smaller ones, and then they are recombined in parallel to each other. Programming the number of paralleled inverter rings allows us to generate the wide-range clock frequencies. This design shuts off some inverters that are not in use to reduce power consumption. To allow the phase-locked loop to shut off inverters, the feasibility of using controllable inverters by the output-switch and power-switch schemes is explored. Theoretical analyses indicate that power consumption of the voltage-controlled oscillator depends on transistors' sizes rather than operating frequencies. By applying the TSMC 0.35-μm CMOS technology, the proposed phase-locked loop that uses the power-switch scheme can yield clock signals ranging from 103 MHz to 1.02 GHz at a supply voltage of 1.8 V. Moreover, power dissipation that is proportional to the number of paralleled inverter rings is measured with 1.32 to 4.59 mW. The phase-locked loop proposed herein can be used in various digital systems, providing power-efficient and wide-range clock signals for task-oriented computations     

Decoupling Control Strategy for Single Phase SPWM Parallel Inverters

A deconpling control strategy of inverter parallel system is proposed based on the equivalent output impedance of single phase voltage source SPWM （sinusoidal pulse width modulation） inverter. The active power and reactive power are calculated in terms of output voltage and current of the inverter, and sent to the other inverters in the parallel system via controller area network （CAN） bus. By calculating and decoupling the circumfluence of the active power and reactive power, the inverters can share load current via the regulation of the reference-signal phase and amplitude. Experimental results of an 110V/2kVA inverter parallel system show the feasibility of the decoupling control strategy.