Synchronous Chopper for Improved Performance Converters

The use of a synchronous chopper in series with a controlled rectifier bridge realizes a viable two-quadrant force-commutated converter with improved performance on the ac side. The synchronous chopper requirements are seen to be significantly different from those of conventional choppers, especially for the regenerating mode. Three chopper topologies are investigated for application in high-power improved performance converter structures. Sensitivity of design parameters to illdefined variables such as line inductance is made an integral part of the design process. The optimum chopper configuration selected is shown to have desirable characteristics, including a reasonably fast and load- independent commutation process, controlled voltage stresses, and a high efficiency.