共查询到20条相似文献,搜索用时 31 毫秒
1.
《Industrial Electronics, IEEE Transactions on》2009,56(8):2862-2874
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Chandra A. Singh B. Singh B.N. Al-Haddad K. 《Power Electronics, IEEE Transactions on》2000,15(3):495-507
This paper deals with an implementation of a new control algorithm for a three-phase shunt active filter to regulate load terminal voltage, eliminate harmonics, correct supply power-factor, and balance the nonlinear unbalanced loads. A three-phase insulated gate bipolar transistor (IGBT) based current controlled voltage source inverter (CC-VSI) with a DC bus capacitor is used as an active filter (AF). The control algorithm of the AF uses two closed loop PI controllers. The DC bus voltage of the AF and three-phase supply voltages are used as feedback signals in the PI controllers. The control algorithm of the AF provides three-phase reference supply currents. A carrier wave pulse width modulation (PWM) current controller is employed over the reference and sensed supply currents to generate gating pulses of IGBTs of the AF. Test results are presented and discussed to demonstrate the voltage regulation, harmonic elimination, power-factor correction and load balancing capabilities of the AF system 相似文献
3.
Three-phase four-wire shunt active filter control strategies 总被引:30,自引:0,他引:30
This paper describes a three-phase four-wire shunt active power filter using a conventional three-leg converter, without the need of power supply at DC bus. Two approaches have been developed to control the active filter. Both control strategies consider harmonics and zero sequence components in the voltage and current simultaneously. The first one provides constant power and the second one sinusoidal current to the source, even under unbalanced voltage conditions. Simulation results from a complete model of shunt active filter are presented to validate and compare the control strategies 相似文献
4.
目前电力系统中有不平衡负荷存在,不平衡负荷会引起电能计量的误差。对于计量误差的处理目前普遍在主站结算并归于线损。文中为判断用户是否使用不平衡负荷及其所引起的误差值,利用电力系统中电压电流关系推算出不能直接测量的电压电流值,并应用三相四线制功率计算方法建立本地功率基准,与实际功率加以比较,判断用户是否存在不平衡负荷,并将计量误差量化。这对于防窃电、安全用电有重要作用,同时对于电力系统的节能降损也起着关键作用。通过Matlab仿真分别对正常用电和存在不平衡负荷用电进行了仿真,验证结果表明,不平衡负荷用电时,存在计量误差,且电力部门少计量了使用不平衡负荷用户所消耗的电能。 相似文献
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《Power Electronics, IEEE Transactions on》2008,23(6):2710-2718
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三相四线制电路中由于非线性负载的大量使用,使得中线上累加了大量的零序谐波电流,给电网的安全运行带来隐患。为此本文提出了一种新的中线零序谐波治理方案,即采用Zigzag变压器与有源电力滤波器(Active Power Filter,APF)相结合的方法。Zigzag变压器因其接线简单、性价比高而在中线谐波治理方面倍受青睐。两者的结合使得目标装置具有较高的性价比和广阔的市场应用前景。经仿真验证,此方案滤波效果在三相负载对称和不对称时均较好,是解决目前日益严重的中线零序谐波污染问题的一种切实可行的方案。 相似文献
7.
A three-phase voltage-source inverter for a power quality compensator under the unbalanced mains and nonlinear loads is proposed to provide balanced three-phase source current and improve input power factor. The proposed converter is based on the conventional three-phase voltage-source inverter with three additional ac power switches to achieve three-level pulsewidth modulation. The voltage stress of three ac power switches is clamped to half the dc-link voltage. The balanced reference mains currents are estimated using the dc-bus voltage and load currents. A proportional-integral voltage controller is used in the outer loop to compensate the switching losses of the voltage-source inverter. To perform the integrated power quality compensation, a hysteresis current control scheme is adopted to track the balanced line current command in phase with mains voltage. Three voltage levels are generated on the ac terminal of the proposed inverter. Computer simulation and experimental results are provided to verify the effectiveness of the proposed control scheme. 相似文献
8.
Shunt active power filters are connected in parallel with the electricity supply network. If the AC mains has a neutral conductor, it is desirable to compensate the mains harmonic currents zero-sequence components. This can be achieved with a four-wire pulsewidth modulation voltage converter connected to the AC mains. In this case, the three-phase and the neutral AC currents must be controlled. A generalization of the space-vector-based current controller in the αβo coordinate system is presented in this paper. With this current controller, all the current harmonic systems of positive, negative, and zero sequence can be injected by the converter and, thus, compensated on the AC mains. The system is also useful to compensate unbalanced currents of fundamental frequency. A useful benefit of this system is that it is possible to control the converter four-wire currents with equal hysteresis errors. Simulation and experimental results are presented 相似文献
9.
正弦脉冲宽度调制(SPWM)技术应用于传统的电压型PWM整流中,SPWM的控制波形可由相间解耦得到。然而,这个过程复杂且直流电压利用率很低。本文提出了一种在同步参考坐标下的三相电压模型的控制策略,空间矢量脉冲宽度调制(SVPWM)。整流器具有高质量的直流侧电压和功率因数。文章提供了MATLAB/SIMULINK的仿真模型。结果证实了模型的正确性及其控制方法。仿真结果表明,与传统的SPWM方法相比,这种方法能明显提高系统的动态性能。 相似文献
10.
The growth in distorting loads has given an interest in the design of three-wire active power filters, switching circuits which can be installed in an installation and generate harmonic currents to neutralize the loads' distorting current. With no neutral, the currents have two degrees of freedom and can be represented by two-dimensional (2-D) vectors. This approach leads to a control strategy which can compensate for balanced three-phase distorting loads. However, there has been a growth of single-phase distorting loads which give large neutral currents at triplen frequencies and which cannot be dealt with by the three-wire active power filter control. This paper reports the development of a three-dimensional (3-D) vector treatment of unbalanced three-phase circuits which can be used instead for the development of a control strategy. Simulation studies show that the control is effective, not only for the removal of harmonics, but also for the compensation of fundamental unbalance currents 相似文献
11.
对于三相四线制供电的配电系统中的单相负载,由于负荷消耗的随机性,经常会引起三相有功负载不平衡。本文提出了一种有效的方法,利用相量图分析了如何用纯电感和纯电容这两种无功元件平衡三相不平衡的有功负载。 相似文献
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14.
《Power Electronics, IEEE Transactions on》2009,24(7):1711-1721
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《Power Electronics, IEEE Transactions on》2009,24(1):45-58
16.
《Industrial Electronics, IEEE Transactions on》2009,56(8):2821-2828
17.
Neacsu D.O. Wagner E. Borowy B.S. 《Industrial Electronics, IEEE Transactions on》2008,55(4):1628-1636
A solution for high current applications consists of paralleling power stages of lower power. Given the complexity of these systems, a comprehensive computer-based analysis is required before physical implementation. This paper presents a simulation benchmark for selection of the pulsewidth modulation (PWM) algorithms used to control interleaved three-and four-wire three-phase power inverters. The analysis considers the resulting phase current harmonics, dc link current harmonics, neutral point voltage, and inter converter circulation currents. Analytical aspects of different current control structures used within interleaved power electronics systems and effects of selecting various PWM algorithms are revealed for both the three-wire and the four-wire structure. Finally, analysis of the DSP implementation for different practical solutions is shown. 相似文献
18.
Escobar G. Valdez A.A. Torres-Olguin R.E. Martinez-Montejano M.F. 《Power Electronics, IEEE Transactions on》2007,22(6):2261-2270
This paper presents a model-based controller for a three-phase four-wire shunt active filter, which uses a three-leg split-capacitor topology to implement the voltage source inverter. The controller is aimed to compensate reactive power and harmonic distortion in the general case of distorted and unbalanced source voltages and load currents, including distorted loads connected between a phase and the neutral line. In addition, the controller is able to compensate for the homopolar component of the load current, that is, the current flowing to the source via the neutral line can be considerably reduced without modifying the actual topology. The complete model in (fixed frame) alphabetagamma-coordinates is presented. Special attention is given to the homopolar component (referred here as the gamma-component) of the line current, source voltage and control input, which are instrumental for the control design purpose. Experimental results in a 2 kVA prototype are provided to illustrate the benefits of the proposed solution. 相似文献
19.
在生产与生活中三相电路的应用最为广泛,针对三相电路运行工况的实验就显得重要而且必然,然而实际的三相电路实验不仅危险性较大,而且一些故障性试验较难进行。电路仿真软件Multisim提供了适用于三相电路仿真的各种元件模型及分析工具,利用该软件对三相电路的3种不对称短路故障进行了仿真分析,与理论分析比较的结果表明仿真软件效果理想。通过虚拟实验分析了负载变化对三相电路的影响,从而得出了照明线路为保持各相电压不变一般采用三相四线制的结论。两组实验表明利用Muttisim可以方便快捷地对三相电路进行各种实验分析。优点明显.适合在电工实验中推广。 相似文献
20.
Fang Zheng Peng Ott G.W. Jr. Adams D.J. 《Power Electronics, IEEE Transactions on》1998,13(6):1174-1181
This paper presents harmonic and reactive power compensation based on a generalized theory of instantaneous reactive power for three-phase power systems. This new theory gives a generalized definition of instantaneous reactive power, which is valid for sinusoidal or nonsinusoidal and balanced or unbalanced three-phase power systems with or without zero-sequence currents and/or voltages. The properties and physical meanings of the newly defined instantaneous reactive power are discussed in detail. A harmonic and reactive power compensator based on the new theory for a three-phase harmonic-distorted power system with zero-sequence components in the load current and/or source voltage is then used as an example to show harmonic and reactive power measurement and compensation using the new theory. Simulation and experimental results are presented 相似文献