SEPIC-SC Rectifier With Continuous Current Feature for Brushless DC Motor Ceiling-Fan

Primary concerns with an existing brushless direct current motor ceiling fan (BLDCMCF) are its high cost, high power, and poor power quality (PPQ) at supply side, which restricts its usefulness. In order to improve functionality and user attraction towards an existing BLDCMCF, this paper presents a solution of issues in it. For this, a discontinuous inductor current mode (DICM) operated AC-DC single-ended primary-inductor converter (SEPIC) with switched-capacitor (SC) is used at front-end. DICM operation simplifies control structure, exhibits inherent power factor correction (IPFC) and helps to make it sensorless using single-turn secondary winding in an intermediate SEPIC inductor, as it requires simple voltage control. Unlike traditional AC-DC SEPIC and Zeta PFC converters, presented SEPIC-SC converter comprises continuous current features at supply and load side, while operating under DICM. Therefore, it shows excellent power quality performance (PQP) with low values of input filter for BLDCMCF. SEPIC-SC converter has low switch stresses, and offers an effective operation over a wide change in output voltage (15V-60V). High DC-link voltage reduces current requirement of the rewound BLDCM, and minimizes i2R losses. Moreover, voltage source inverter (VSI) losses are minimized with its fundamental-switching (.50Hz), which simplifies motor control. With these changes, BLDCMCF significantly lowers power-input, overall-cost, and offers a high PQP. Finally, a prototype is built to verify functionality and effectiveness of a presented BLDCMCF.