A new zero-voltage-transition (ZVT) two-quadrant (2Q) converter for DC motor drives is presented. It possesses the definite advantage that both main switches and diodes can operate with zero-voltage switching in both motoring and regenerating modes, while both of these switches are subjected only to unity voltage and current stresses, namely the same as their PWM counterpart. This converter is particularly useful for DC traction systems in which both motoring and regenerative braking are desired to have high efficiency. The corresponding theoretical analysis and its high-efficiency performance are verified by both simulation and experimental results. © 1998 Taylor and Francis Group, LLC.