共查询到20条相似文献,搜索用时 31 毫秒
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提出了新型并网逆变器的高阶功率滤波器的拓扑电路,称为LLCL滤波器。采用新型LLCL型滤波器对单相光伏并网逆变器进行滤波,LLCL滤波器通过在传统LCL滤波器的电容支路中串联一个小的电感达到在开关频率处产生串联谐振,相比LCL型滤波器能够更大程度地对串联谐振频率处的电流谐波进行衰减,可以减少电感装置的体积和重量,减少动态响应时间。更重要的是,能够减少电网侧的电感值,这样可以提高特征谐振频率点,有利于并网逆变器的控制。对比分析了传统LCL滤波器和LLCL滤波器的性能,证实和评估LLCL滤波器的优越性。对LLCL滤波器进行了参数设计,使用Matlab仿真软件搭建模型,仿真结果表明系统具有较好的稳态性能,且抗干扰性能好。 相似文献
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A new approach for digital feedback control of a PWM inverter is proposed, in which an output DB (deadbeat) control is achieved combined with a disturbance observer. In the proposed scheme, the pole placements of the state observer and the disturbance observer are chosen separately. When the two observers employed the same pole placements, the experimental setup had a tendency to become unstable due to the detection error. By selection of the different pole placements, the disturbance observer quickly estimates the disturbance and feedforward disturbance cancellation is achieved. Then the state observer estimates the state variables at the next sampling instant, and the deadbeat controller is applied to the nominal system. This scheme has advantages in robustness in the practical application. From the view point of UPS applications, the advantages and disadvantages are discussed through simulations and experiments. Compared with other digital control laws, the superiority of the proposed control law is verified 相似文献
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LCL滤波器可以有效抑制高次谐波,然而LCL滤波器的使用增加了系统阶数,对系统控制策略提出了更高的要求。为此,采用一种基于极点配置的电流双环控制策略,以DSP作为主控制器,充分利用DSP控制器的CLA、高精度PWM和AD等模块,使其硬件电路大大简化。最后,通过极点配置的方法选定控制参数,整个系统操作简单、控制灵活、功能强大,实现了节能降耗和精密制动。 相似文献
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LCL滤波器在并联型有源电力滤波器中的设计 总被引:1,自引:0,他引:1
在满足相同的高频滤波效果的情况下,LCL滤波器所需的总电感值比L滤波器小,因此更适于在大功率、开关频率较低的电流源控制型并网设备上应用。然而针对该类型滤波器的参数设计不仅关系到开关频率处纹波抑制效果,同时也会影响电流控制器的性能。随着高频谐波抑制效果明显的LCL滤波器在并联型有源滤波器中应用,基于谐波电流跟踪控制器的LCL参数设计需要进一步研究,因此文中基于并联型有源电力滤波器给出一套LCL滤波器设计方法,并通过仿真验证该LCL滤波器的有源电力滤波器的有效性。 相似文献
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Sheng-Ming Yang Chen-Haur Lee 《Power Electronics, IEEE Transactions on》2002,17(5):772-778
Accurate stator current control is essential in high performance field orientation-controlled induction motor drives. Any current error degrades the drive's performance in the same way as an incorrectly tuned field orientation. This paper presents an efficient current control scheme that can achieve high accuracy and a fast dynamic response. This scheme uses voltage decoupling and deadbeat control loops. The decoupling controller provides the voltage needed to oppose the motor's back EMF. The deadbeat controller reduces the current error as fast as possible and stabilizes the system. The control law does not require knowledge of the rotor flux and is independent of the field orientation control tuning. Good static and dynamic performances were obtained in both the simulation and experimental verifications. Because the motor leakage inductance and resistance information were required for this control method, the influence of the estimation errors for these parameters was also investigated. The results show that the leakage inductance model error might cause a current ripple. However, this parameter can be tuned to its correct value easily by inspecting the current response. 相似文献
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由于对高频谐波的抑制效果明显好于L型滤波器,因此LCL滤波器在电流源控制的并网逆变器中应用越来越广泛。而针对该类型的并网逆变器的控制策略更为复杂,为了简化控制策略一种基于电流双环的并网控制方案被提出来。与电压电流的双环控制器设计方法不同,设计电流双环控制器参数时除了考虑内外环控制器的相互影响以外,还需要考虑双环控制器带来的降阶和少自由度问题。因此本文在介绍基于高阶极点配置的电流双环控制器设计方法的基础上,重点分析在电流双环控制带来的少自由度的情况下如何合理的设计控制器参数。实验结果表明,根据该方案设计的控制器参数能够使三相并网逆变器安全、可靠运行且具有较快的动态响应速度。 相似文献
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Active compensation of torque harmonics in high-performance synchronous permanent magnet (PM) motor drives requires high-bandwidth current control. It is demonstrated that proportional integral (PI) current control exhibits performance limits, even when feedforward compensation of the rotor induced voltage and the stator inductance drop is used. High bandwidth requirements are satisfied using a digital deadbeat current controller. Sampling time delays are eliminated to the extent possible by means of a current predictor. The current controller and the predictor refer to a model of the parasitic effects of the PM synchronous machine that is acquired and adapted to parameter changes in real time. Stator current distortions due to deviations from the sinusoidal flux linkage distribution are thus eliminated. The control system facilitates compensation of high-frequency torque ripple of the machine 相似文献
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倒立摆状态反馈极点配置与LQR控制Matlab实现 总被引:2,自引:0,他引:2
为了实现对绝对不稳定的非线性多变量倒立摆系统的控制,采用了状态反馈极点配置和LQR控制2种方法。状态反馈极点配置是将多变量系统的闭环系统极点配置在期望的位置上,从而使系统满足瞬态和稳态性能指标。LQR算法是在一定的性能指标下,利用最少的控制能量,来达到最小的状态误差。通过Matlab软件仿真实验,发现2种控制方法对于倒立摆这种不稳定的系统有一定的控制作用,证明了两种控制方案的可行性和有效性。仿真表明二次型最优控制有较小的振荡和超调量,对系统有更好的控制效果。 相似文献
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A space vector-based rectifier regulator for AC/DC/AC converters 总被引:12,自引:0,他引:12
A voltage-sourced rectifier control scheme for use with AC/DC/AC variable speed drives is presented. A control scheme is derived that directly calculates the duration of time spent on the zero state and on each switching state adjacent to the reference vector, over a constant switching interval, in order to drive the line current vector to the reference vector. In addition, under transient conditions, when deadbeat control is not possible, a control scheme is presented that ensures that the line current vector is driven in the direction of the reference current vector. The current reference for the rectifier controller is derived from the bus voltage error and a feedforward term based on the estimated converter output power. The proposed space vector-based rectifier regulator is shown to exhibit improved harmonic and transient performance over existing per-phase duty cycle prediction methods, especially at modulation indices near unity. The deadbeat control of the rectifier input current is accomplished every half-cycle with constant switching frequency while still symmetrically distributing the zero state within the half-cycle period 相似文献
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Critical inductance in voltage regulator modules 总被引:1,自引:0,他引:1
Pit-Leong Wong Lee F.C. Peng Xu Kaiwei Yao 《Power Electronics, IEEE Transactions on》2002,17(4):485-492
Multichannel interleaving makes it possible to use small inductances to improve voltage regulator modules' (VRMs) transient responses. However, smaller inductances reduce efficiency. Analysis shows that the transient responses are not only determined by the inductances but also the control bandwidths. This paper presents the concept of critical inductance in VRM. Critical inductance is the largest inductance that gives the fastest transient responses. Critical inductance is a good reference for optimal VRM design. Critical inductance is a function of the feedback control, the step current magnitude and the steady-state operating point 相似文献
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为了提高新能源整个并网系统的性能,在分析无差拍控制和PI控制的工作原理基础上,提出了基于电流无差拍和PI复合控制的PWM逆变的控制策略。通过Matlab/Simulink建模仿真三相并网系统,采用LCL滤波器滤波。当系统接三相对称纯阻性负载和整流性负载时,将系统逆变电压与电网电压、逆变电流与电网电压进行比较,以及对三相逆变电流进行谐波分析。仿真结果表明,该并网控制策略能较好地跟踪电网电压,波形畸变较小、动态响应快。 相似文献
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新能源并网逆变器入网电流通用控制 总被引:1,自引:0,他引:1
太阳能电池、风力发电,以及燃料电池等新能源发电中的并网逆变器技术的研究已经成为一个重要的研究方向。为了消除逆变器输出电流中的高次谐波,通常采用LCL滤波器对谐波进行处理。但是LCL滤波器是无阻尼三阶系统,使输出容易产生谐振,因此逆变器电流控制器的研究成为了研究的热点。本文就当今使用较为热门的电容电流内环、入网电流外环的双闭环控制策略进行分析,使用MATLAB/Simulink进行仿真,并在仿真中加入功率因数(PF)的验证。从仿真结果看出该方案可有效地避免入网电流谐振,入网电流能很好地跟踪并网电压,达到同频同相,功率因数约等于1,并且在FFT谐波分析中达到满意的效果。 相似文献
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Grid current regulation of a three-phase voltage source inverter with an LCL input filter 总被引:16,自引:0,他引:16
Many grid connected power electronic systems, such as STATCOMs, UPFCs, and distributed generation system interfaces, use a voltage source inverter (VSI) connected to the supply network through a filter. This filter, typically a series inductance, acts to reduce the switching harmonics entering the distribution network. An alternative filter is a LCL network, which can achieve reduced levels of harmonic distortion at lower switching frequencies and with less inductance, and therefore has potential benefits for higher power applications. However, systems incorporating LCL filters require more complex control strategies and are not commonly presented in literature. This paper proposes a robust strategy for regulating the grid current entering a distribution network from a three-phase VSI system connected via a LCL filter. The strategy integrates an outer loop grid current regulator with inner capacitor current regulation to stabilize the system. A synchronous frame PI current regulation strategy is used for the outer grid current control loop. Linear analysis, simulation, and experimental results are used to verify the stability of the control algorithm across a range of operating conditions. Finally, expressions for ""harmonic impedance" of the system are derived to study the effects of supply voltage distortion on the harmonic performance of the system. 相似文献
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VSC-HVDC在电网电压不平衡情况下,输出功率及直流母线电压会产生二倍频波动,进而影响系统的稳定运行。文中研究了柔性直流输电系统在电压不平衡情况下的改进无差拍控制策略,该策略以瞬时有功功率波动分量为零为约束条件,推导了正负序参考电流表达式。针对传统无差拍控制算法存在的控制延时及对交流侧电感参数变化鲁棒性差的问题,提出了一种改进无差拍控制策略。该控制策略利用拉格朗日插值法预测出下一个采样时刻的参考电流;对电网电压进行了线性预测;对网侧电流进行了非线性预测。最后借助MATLAB/Simulink平台搭建相应的仿真模型,仿真结果证明了该控制策略的正确性和有效性。 相似文献
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Dong Seong Oh Kwan Yuhl Cho Myong Joong Youn 《Power Electronics, IEEE Transactions on》1992,7(2):364-373
A current control technique for a voltage-fed PWM inverter is presented. The discretized state equation of an inverter and a load independent of operating conditions with the delayed input voltage feedback has been derived using the averaging concept. The discretized current controller is proposed to reduce the current error as fast as possible using the deadbeat control strategy and to stabilize the closed loop system asymptotically when the variations of load parameters are given in the predetermined stabilized region. This proposed control scheme is realized by the symmetrical uniform sampling method and is easily implemented using a microprocessor-based system. Computer simulation for the proposed controller has been carried out and the results show good static and dynamic performances 相似文献