Design of a soft switched 8kW battery charging converter for 100% Low Floor Light Rail Vehicle

100% LFLRV (low floor light rail vehicle) is a new-style, humanized urban rail transit Vehicle. The design challenges for 100% LFLRV BCC (battery charging converter) main circuit were presented. A 20 kHz, 8 kW full bridge ZVS (zero voltage switching) DCDC converter with phase shift PWM control was developed. ldquoDSP + CPLDrdquo mode was employed in control system to perform full process digital management. To avoid the DC bias of high frequency transformer, a full digital control solution was adopted, rather than other traditional solution, such as connecting the blocking capacitors in series in main circuit. The phase shift drive pulses were generated by DSP controller, instead of analog controller like UC3879. Still, the optimal IUOU battery charge characteristics curve was introduced. In the end, the experimental prototype was presented and some experiment waveforms and analysis were given. The conclusions show that the developed full digital control battery charger is stable, reliable and accordant with the 100% LFLRV designing.