A Novel Soft Switched Improved Power Quality Converter Fed D.C. Motor Drive

In this paper, an attempt is made to improve the performance of DC drive by reducing motor ripples and discontinuous armature current operation and simultaneously maintain the high power factor and better input power quality in the entire load torque and current range of the motor. The improved power quality converter makes the input power factor unity over a wide operating shaft speed range, also reduces the total harmonic distortion (THD) of input supply current, and nearly ripple free the armature current and voltage waveform. Increase in switching frequency has the advantageous effects on both the amplitudes and the orders of load ripples and line harmonics besides having the advantage of lower armature series inductance requirement in case of controlled DC drives.