A tremendous increase in the industrial and commercial applications of low voltage variable frequency drives (VFD) has been observed in the last decade. VFD are mainly used for energy saving and reliable speed control of industrial motors in an electrical system. However, power quality issues are becoming more apparent due to the installation of VFD. In this paper, a nonintrusive technique has been employed to determine the optimum operation of VFD system for improving the performance of heating, ventilation, and air conditioning centrifugal chiller system. The effect of load and speed ratios of VFD systems on total harmonic distortion (THD), power factor, distortion loss ratio, temperature, and efficiency has been investigated. The measurement of these parameters has been carried out by performing a series of experiments under variable operating conditions. The binomial relations have been developed between the various performance parameters and the operating conditions. Based on experimental results, optimum operating conditions have been proposed and implemented for the VFD system. Moreover, the results have been compared with the existing operating conditions and indicate a considerable improvement in THD, power factor, distortion loss ratio, efficiency, and the annual cost of energy consumed.

中文翻译：

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低压变频器的最佳运行，以改善采暖，通风和空调冷却器系统的性能

在过去的十年中，已经观察到低压变频器（VFD）在工业和商业应用中的巨大增长。VFD主要用于节能和电气系统中工业电机的可靠速度控制。但是，由于安装了VFD，电源质量问题变得更加明显。在本文中，非侵入式技术已被用来确定VFD系统的最佳运行，以提高采暖，通风和空调离心式冷却器系统的性能。研究了VFD系统的负载和速度比对总谐波失真（THD），功率因数，失真损耗比，温度和效率的影响。这些参数的测量是通过在可变操作条件下进行一系列实验来进行的。已经在各种性能参数和操作条件之间建立了二项式关系。根据实验结果，已为VFD系统提出并实现了最佳操作条件。此外，将结果与现有的运行条件进行了比较，表明总谐波失真，功率因数，失真损耗比，效率以及每年消耗的能源成本都得到了显着改善。