Ćuk topology based high performance three phase to single phase Switch Mode cycloconverter with V/f motor control

Abstract

In this paper, a high performance Switch Mode Power Supply (SMPS) using a three-phase to single-phase AC cycloconverter is proposed. The proposed SMPS based cycloconverter is implemented using the Ćuk topology, which has higher reliability, low switching losses and thereby increased efficiency as the number of switches is reduced. It also provides means to have high input power factor and low input current Total Harmonic Distortion (THD) with use of simple input and output filter. Incorporation of SMPS topology enables the proposed circuit to operate in either buck or boost voltage mode. The proposed topology ensures high performance by maintaining reduced input current THD (below 10%), improved input power factor (above 0.85), and better efficiency (greater than 85%) as the duty cycle of the PWM control signal is varied for resistive load while the voltage gain is varied between 50% to 150%. The improvement in converter performance is compared with the conventional 12-SCR three to single phase AC cycloconverter. Furthermore, a closed loop control circuit is designed to provide V/f control while the cycloconverter is employed to drive machines with constant flux at low speed. The integration of control circuit provides enhanced reliability and better grip over the output voltage and frequency of the cycloconverter.