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采用新型H10三相逆变器抑制光伏并网系统中的泄漏电流与电流谐波

Mitigation of Leakage Current and Current Harmonics in PV Grid-Connected Systems Using a New H10 Three-Phase Inverter

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中文摘要

本文提出一种新型10开关(H10)逆变器,用于抑制光伏并网系统中的共模电压(CMV)、泄漏电流及电网电流谐波。所设计的空间矢量脉宽调制(SVPWM)策略将CMV波动范围限制在Vdc/3至2Vdc/3之间,dv/dt为Vdc/6,性能接近三电平逆变器但开关数量更少。该SVPWM在零电压矢量期间实现光伏侧与电网的隔离,并减少CMV跳变次数,从而有效降低泄漏电流和输出电流谐波。系统具备自平衡中点电压能力,且通过数学分析与实验验证。仿真与实验结果表明,相较于H8及现有H10拓扑,所提方案在抑制CMV和泄漏电流方面更具优势。

English Abstract

This article proposes a new 10-switch (H10) inverter to alleviate the leakage current and grid current harmonics in grid-connected photovoltaic (PV) systems. A space vector pulsewidth modulation (SVPWM) control approach has been developed for this inverter to maintain an overall fluctuation of the common mode voltage (CMV) between V_ dc/3 and 2V_ dc / 3 with a dv /dt of V_ dc/6 , which is similar to the three-level inverters with smaller number of switches. Furthermore, the proposed SVPWM for this new inverter isolates the PV from grid during the zero voltage vectors. Additionally, the number of CMV transitions will be reduced, resulting in a lower leakage current and less harmonics in output currents. Moreover, the self-balancing neutral point voltage (NPV) of the proposed system will be mathematically and experimentally proved. The performance of the PV grid-connected system with the proposed H10 inverter will be compared to other topologies in the literature, e.g., H8 and H10 inverters. Numerous MATLAB simulations and experimental results indicate the effectiveness of CMV and leakage current reductions of the proposed inverter.
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SunView 深度解读

该H10逆变器拓扑对阳光电源SG系列光伏逆变器及ST储能变流器具有重要应用价值。其将CMV波动限制在Vdc/3-2Vdc/3范围、dv/dt降至Vdc/6的特性,可直接应用于非隔离型光伏并网系统,有效解决薄膜组件泄漏电流超标问题。相比传统H6/H8拓扑,该方案在零矢量期间实现PV侧与电网隔离,可优化SG系列高频开关策略,降低EMI滤波器成本。其自平衡中点电压能力对阳光电源三电平拓扑设计具有借鉴意义,可简化ST系列储能变流器的电压均衡控制算法。建议评估该拓扑在1500V高压系统中的器件应力分布,结合SiC器件应用进一步提升功率密度。