A bi-directional induction motor drive with high power quality

This paper presents the modeling, design, and analysis of a thyristor-based, current-controlled bi-directional AC-DC converter. The converter is not only capable of featuring bi-directional power flow, but also offers unity power factor and a near sinusoidal current waveform at the AC side in both powering and regenerating modes. By applying the y-parameter modeling technique, small-signal models of the converter and a unified feedback controller circuit for both modes are derived. Systematic procedures for determining the circuit components in the power conversion stage and the feedback controller are described. The operation is illustrated with the design of a 500 W, 100 V(AC)/200 V(DC) prototype converter, supplying to a voltage fed induction motor drive. Experimental results showing operation in the powering mode, regenerating mode and during mode changeover are given, confirming the feasibility of the proposed design technique and the operation of the converter