Regenerative and ride-through capability for AC drives through thyristor-based extensions of the diode front-end - Industry Applications Conference, 2003. 38th IAS Annual Meeting. Conference Record of the

This paper presents SCR-based circuit extensions to a diode rectifier to allow regeneration during braking and ride-through during voltage sags. The proposed topology uses two line-commutated SCR bridges – one connected to the dc bus rails and the other to the dc bus center-tap. The inverting SCR bridge connected to the dc bus rails transfers energy from the dc link to the mains during regeneration. The bridge connected to the center-tap provides improved commutation to the inverting bridge. In addition, it can be used to boost the dc bus during input voltage sags. The circuit provides a lower cost alternative to PWM rectifiers and other currently used regenerative and ridethrough modules. Advantages of the proposed SCR-based circuit include low cost and ruggedness. Simulation waveforms are presented to indicate circuit operation.