Abstract

This paper presents a detailed performance analysis of multilevel inverter for both stand-alone and grid connected PV systems. Here, converter circuit is not only tested for parameters like total harmonic distortion (THD), power output and system efficiency by connecting the non-linear load but the variations of power factor is also considered which is not found commonly. First the simulated results for THD, power output and efficiency are tabulated with variation of load power factor individually for both systems and best operating power factor is found with respect to distortions and efficiency respectively. For Stand-alone system, circuit efficiency as high as 96.8% is achieved when operated at 0.85 power factor. Then the analytical analysis has been carried out for grid connected system where efficiency of 84.3% is achieved for 60^o grid phase angle and 75.8% for 10^o and thus proposing operation at higher grid phase angle. Harmonic components have been further reduced and brought below 5% level by means of passive filters. Finally, to validate the proposed outcome, simulated results have been compared with analytical results and corresponding plots have been shown.

中文翻译：

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提高独立系统和并网系统的太阳能逆变器性能

摘要

本文对独立和并网光伏系统的多电平逆变器进行了详细的性能分析。这里，转换器电路不仅通过连接非线性负载来测试总谐波失真（THD）、功率输出和系统效率等参数，还考虑了通常不存在的功率因数的变化。首先，将两个系统的 THD、功率输出和效率的模拟结果与负载功率因数的变化分别制成表格，并分别针对失真和效率找到最佳运行功率因数。对于独立系统，当功率因数为0.85时，电路效率高达96.8%。然后对并网系统进行了分析分析，60次时效率达到84.3%^o电网相位角为 10 ^o的 75.8% ，因此建议在更高的电网相位角下运行。通过无源滤波器，谐波分量进一步减少并降至 5% 以下。最后，为了验证所提出的结果，将模拟结果与分析结果进行了比较，并显示了相应的图。