A Novel Three-Phase Induction Motor Drive for Domestic Fan Application with Improved Reliability

Electrolytic capacitors are popular in high power motor drive systems due to their high capacitance per unit volume and ride through capability. However, their short lifetime jeopardizes the reliability of the drive, and their high capacitance value results in a highly distorted grid current. This paper proposes a novel electrolytic capacitor-less, induction motor drive (IMD) system for domestic fan application. The drive circuit consists of a 1-phi bridge rectifier, a small dc-link film capacitor, and a three-leg inverter. A design methodology is presented to calculate the value of the do-link capacitor. The double-line frequency ripple superimposed on the electromagnetic torque due to the rectification stage is suppressed by multiplying the carrier wave with the measured dc-link voltage. A modified common mode injection scheme is used to reduce the switching loss of the system further. V/F control is adapted to vary the speed of the fan. The analytical and simulation results are included.