A new threephase DC/DC converter integrated system was presented to realize a permanentmagnetdrive reconstructed onboard charger, which integrated permanent magnet machine windings and DC/AC converters into an onboard charger to achieve drivecharging integration in electric vehicle, and aimed at high space utilization, fast charging and high reliability. The structure and working principle of the integrated system were analyzed, and the mathematical model of the threephase DC/DC converter of the charging system was deduced. Based on this, the simulation model of the drivecharging integrated system was built by MATLAB/Simulink simulation software. The performances of two pulse width modulation (PWM) control strategies were evaluated based on the comparison of the ACside voltage, ACside current, DCside machine winding inductor current and DCside voltage waveform. The simulation results showed that compared with the interleaved PWM control strategy, the new reconstructed onboard charger system had better running performance under the synchronous PWM control strategy.