Effects of Source Voltage Harmonics on Power Factor Compensation in AC Chopper Circuits

In recent years, the detailed modelling of power electronic devices and their behaviours on various system conditions are a great concern of the power industries and customers. One of the widely proliferated such devices is the triac controlled ac choppers. Although these types of devices have important application areas, their poor power factor is the main obstacle for the large scale implementation in power systems. This paper presents an analysis on the behaviour of a single phase load composed with triac controlled ac chopper during the reactive power compensation with a basic capacitor in nonsinusoidal voltage case. The results of these analysis show that the distortion of voltage improves power factor, which is contradicting with previous findings, for the high conduction angles of triac controlled ac chopper. In addition, it is observed that the performance of power factor improvement with a basic capacitor is noticeably affected by the phase angles of voltage harmonics, which is an extensively ignored issue in the literature.