Power Quality Improvement using Canonical Switching Cell Converter Fed BLDC motor drive

Abstract: Power factor correction (PFC) methods shapes the input current to maximise the real power from the supply mains. And they are also employed in present power supplies to comply with regulatory requirements. The rectifier circuits with power factor correction generally employs boost converters and as a result the output voltage becomes limited. To expand the controlled voltage range, buck-boost or Cuk converter types should be utilized. The converter which is advantageous over other converters must be utilised. Here the 'canonical switching cell' (CSC) converter is employed and it is advantageous over other converters. In this paper, the design and simulation of a reduced sensor based CSC converter fed brushless dc motor (BLDCM) drive for low-power household applications is discussed. The BLDCM is electronically commutated for reduced switching losses in voltage source inverter (VSI) due to low-frequency switching. By varying the dc-bus voltage of VSI, the speed of BLDCM is controlled. A front-end CSC converter operating in discontinuous inductor current mode (DICM) is used for dc-bus voltage control with unity power factor at ac mains, then voltage follower method can be effectively used. Since voltage follower method is used for the control, only one voltage sensor is needed which is advantageous. And also it is a cost-effective method. From the simulation analysis it is observed that the THD is improved drastically by employing this converter and the analysis of the circuit is also performed. Keywords: Brushless dc motor (BLDCM), canonical switching cell (CSC) converter discontinuous inductor current mode (DICM), power factor correction (PFC).