共查询到18条相似文献,搜索用时 234 毫秒
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研究了二极管钳位型三电平逆变器的中点电压平衡控制方法.建立了三电平逆变器的综合数学模型,提出了一种采用最近三矢量法合成参考矢量的空间矢量脉宽调制SVPWM算法,给出了小三角形区域判断规则、合成参考电压矢量的相应输出电压矢量的作用顺序,并推导出各合成电压矢量的作用时间.探讨了影响三电平逆变器中点电压平衡的主要因素,提出了... 相似文献
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三电平变频器以其优越的性能,特别是在大功率伺服系统中的应用,以逐渐淘汰两电平变频器。在三电平sVPwM控制中,关键问题之一是直流侧中点电位波动的问题,中点电位的波动直接影响输出波形的质量。文章通过对NPC型三电平sVPWM控制中各矢量作用状态的研究,以逆变器为例,深入分析了直流侧中点电位波动的原因,给出了矢量合成时中点电压平衡区域。通过改进SVPWM算法实现了中点电位的控制,使其更加平稳。 相似文献
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本文深入研究了空间矢量调制模式下的三电平逆变器中点电压波动的机理,建立了平均中点电流数学模型,为中点电压平衡控制提供了理论依据,并提出基于电压中矢量合成的中点电压平衡控制方法,该方法对于系统动态过程中出现的电压不平衡,可以通过调整冗余小矢量的相对作用时间进行补偿,由于电压中矢量的部分作用时间被均分给相应的小矢量,因此其补偿效果明显。实验结果证实了本文研究方法的正确性。 相似文献
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针对中点嵌位型(Neutral Point Clamp,NPC)三电平逆变器的中点电压波动会引起输出电压失真的问题,设计了一种观测器对中点电压波动进行观测,并根据观测结果设计了模糊PI控制器对其进行控制。首先建立了NPC三电平逆变器的数学模型,通过对直流侧电容电压的数学模型进行分析,将逆变器的中点电位不平衡问题近似为系统存在扰动下的误差估计;其次,根据模糊逻辑规则定义了新的误差变量,设计了模糊PI控制器,对中点电位波动问题进行控制;最后通过仿真和实验结果表明:设计的观测器可有效完成对中点电位的准确观测,利用模糊PI控制器实现了对中点电压波动的有效控制。 相似文献
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T型三电平逆变器作为常见的光伏并网逆变器拓扑结构之一,因其能够能量双向流动的特点,时常被用做储能设备与电网之间的能量转换器,在微电网电压波动时对微电网进行削峰填谷。针对T型三电平逆变器双向控制这一点,在传统的SVPWM调制策略的基础上设计了电压电流双闭环控制,以此来控制电流的双向流动。实验波形验证了这一方法的有效性。 相似文献
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Three Phase Three-Level PWM Switched Voltage Source Inverter With Zero Neutral Point Potential 总被引:1,自引:0,他引:1
《Power Electronics, IEEE Transactions on》2006,21(5):1320-1327
A new three phase three-level pulsewidth modulation (PWM) switched voltage source inverter with zero neutral point potential is proposed. It consists of three single-phase inverter modules and each module is composed of a switched voltage source and inverter switches. The major advantage is that the peak value of the phase output voltage is twice as high as that of the conventional neutral-point-clamped PWM inverter. Thus, the proposed inverter is suitable for applications with low voltage sources such as batteries, fuel cells, or solar cells. Furthermore, three-level waveforms of the proposed inverter can be achieved without the switch voltage unbalance problem. Since the average neutral point potential of the proposed inverter is zero, a common ground between the input stage and the output stage is possible. Therefore, it can be applied to a transformerless power conditioning system. The proposed inverter is verified by a PSpice simulation and experimental results based on a laboratory prototype. 相似文献
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A two-level four-leg inverter has been developed for the three-phase four-wire power quality compensators. When it is applied to medium and large capacity compensators, the voltage stress across each switch is so high that the corresponding dv/dt causes large electromagnetic interference. The multilevel voltage source inverter topologies are good substitutes, since they can reduce voltage stress and improves output harmonic contents. The existing three-level neutral point clamped (NPC) inverter in three-phase three-wire systems can be used in three-phase four-wire systems also, because the split dc capacitors provide a neutral connection. This paper presents a comparison study between the three-level four-leg NPC inverter and the three-level NPC inverter. A fast and generalized applicable three-dimensional space vector modulation (3DSVM) is proposed for controlling a three-level NPC inverter in a three-phase four-wire system. The zero-sequence component of each vector is considered in order to implement the neutral current compensation. Both simulation and experimental results are given to show the effectiveness of the proposed 3DSVM control strategy. Comparisons between the 3DSVM and the 3-D hysteresis control strategy are also achieved. 相似文献
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三电平中点箝位逆变器在高压大容量变频调速中得到了广泛的研究和应用,文中对二极管箝位型三电平逆变器的控制系统进行研究并介绍采用CPLD与DSP的组合来实现三电平逆变器空间矢量发生的一个方法。这种方法可以控制中点电位平衡,限制输出电压dw/dt。试验结果体现了该方法的可行性。 相似文献
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《电子学报:英文版》2016,(5):965-973
Z-source Neutral point clamped (NPC) inverter inherits the advantages of Z-source inverter,which can buck-boost energy and allow the shoot-through states.At the same time,Z-source NPC inverter has high running efficiency and less harmonic content.Hence,it can be widely used in motor drives and fuel cell applications.When increasing the modulation index,one can only get smaller shoot through value in Z-source NPC inverter,therefore the output voltage of the inverter can not be boosted very high.In this paper,a novel cascaded Z-source neutral point clamped inverter is proposed by cascading two Z-source networks in series.An Alternative phase opposition disposition (APOD) carrier-based modulator is applied to control the proposed Z-source inverter.To confirm the operating principle of the new Z-source NPC inverter,a generic APOD carrier-based modulator for the cascaded Z-source NPC Inverter under Matlab/Sinmulink is built.The simulation results show that the boost factor has been increased from 1/(1-2D) for the traditional Z source NPC inverter to 1/(1-4D) for the proposed cascaded Z-source NPC inverter.A prototype of the cascaded Z-source NPC inverter has been set up.The experimental results verify that the new topology can increase the boost factor and expand the voltage regulation range of the inverter. 相似文献
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A dual two-level inverter scheme with common mode voltage elimination for an induction motor drive 总被引:1,自引:0,他引:1
Baiju M.R. Mohapatra K.K. Kanchan R.S. Gopakumar K. 《Power Electronics, IEEE Transactions on》2004,19(3):794-805
Pulse-width modulated (PWM) inverters are known to generate common mode voltages which cause motor bearing currents in the induction motor drives. They also result in leakage currents which act as sources of conducted electromagnetic interference in the drive system. The common mode voltage generated by a conventional three-level inverter can be eliminated by switching only the voltage space vectors which do not produce the common mode voltage. This paper presents a PWM switching strategy to eliminate common mode voltage using the open-end winding configuration for the induction motor. The switching strategy presented in this paper, does not generate any alternating common mode voltages in the drive system and hence the electrostatic coupling of the common mode voltage, which results in the bearing currents and the leakage currents, is avoided. The proposed scheme is devoid of neutral point voltage fluctuations and does not require neutral point clamping diodes, when compared to the common mode elimination scheme based on the conventional three-level inverter topology. Also, the present scheme uses a single dc-link with half the voltage compared to the conventional three-level inverter based scheme. 相似文献
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Muhammad Jamil 《International Journal of Electronics》2013,100(12):1293-1303
This article presents carrier-based modulation strategies for a neutral point clamped inverter that substantially reduces harmonics in the output line to line voltages, phase voltages, reference voltages and common mode voltage. A graphical technique that has already been proposed in the literature and that also allows various carrier disposition modulation strategies for a diode clamped inverter is being described here. For this graphical technique two new modulation strategies – alternative phase opposite disposition (APOD) and phase disposition (PD) – are being used to create reduced harmonics for diode-clamped inverters under both continuous and discontinuous switching conditions. These strategies can be further expanded in a very simple way. A comparison of conventional-, APOD- and PD-strategies will be given by simulation results by using the software ‘Simplorer’ and ‘Post Processor Day’. The common mode voltage has been reduced particularly with PD-strategy. The strategies have been confirmed using a three level inverter for medium voltage. 相似文献