One cycle controlled bridge-less SEPIC converter fed BLDC motor drive

This paper presents a One Cycle Controlled (OCC) Bridge-less (BL) SEPIC converter fed Brush-Less DC (BLDC) motor drive for air conditioning application. The speed control of proposed drive is obtained by Pulse Amplitude Modulation (PAM) of three-phase Voltage Source Inverter (VSI). The Pulse Amplitude Modulation is facilitated by the DC bus voltage variation via duty ratio modulation of BL-SEPIC converter switches. A non-linear technique called One Cycle Control (OCC) is used to accomplish the duty ratio control of BL-SEPIC converter. Autoshaping of supply current is achieved by designing BL-SEPIC converter to ensure Discontinuous Inductor Current Mode (DICM) operation. The Total Harmonic Distortion (THD) of supply current is maintained within the limits as specified by IEC-61000-3-2. The proposed system is designed and simulated in MATLAB/Simulink environment and its performance is analyzed for speed control over a wide range.