This paper discusses about a nonlinear control technique employed for AC/DC PFC converter to charge the battery of PHEV. It consists of two stages, first stage is conversion from ac to dc where the power factor improvement is achieved by reducing the harmonics at the input side. In second stage, output dc voltage is boosted according to the requirement. The control law implemented in the first stage is based on discrete energy control which helps in recovering the output at a faster rate during transient period. This also helps in maintaining unity power factor at the input side. The discrete optimal control is compared with the average current mode control and the significant simulation results are presented. From the results it is depicted that the discrete energy function control has a good dynamic response for load transients compared to average current mode control.