Power Factor Analysis of an Energy Efficient Single Phase VFD for Industrial Sewing Machines

The Ready-Made Garments (RMG) sector plays a huge role in the Bangladesh economy in terms of employment, foreign exchange earnings and its contribution to GDP. Mainly clutch motors are used in this industry which has no speed control, low starting torque, energy loss through heat and motor burn problems, etc. A VFD based inverter can protect the motors from these problems. Moreover, a stand by position for controlling the speed by VFD during no-load time can make the system more energy efficient. But, an inversion process can affect the line power factor though it increases the system efficiency. In this paper, the field implemented data of a 1kW capacity VFD for clutch motors is shown. Efficiency improvement and distortion in PF is analyzed by field implementation and lab experiment. In addition, in this paper, a boost converter integrated VFD inverter is also analyzed for the specific capacity to get an ideal power factor with improved efficiency.