Universal input battery charger circuit for PHEV applications with simplified controller

Plug-in hybrid electric vehicles (PHEVs) are equipped with a high energy density battery pack, which should be externally charged form the grid. This requires a high power battery charger circuit which can operate at universal input voltage and be capable of maintaining the required output voltage and current with low ripple. The topology composed of PWM boost rectifier cascaded with a bidirectional DC/DC converter is a simple and low cost solution for this application. However, when individual average mode current controllers are used for each converter, the controller parameters have significant effect on the circuit performance. Moreover, feedforward compensator is necessary at the AC/DC conversion stage, if the circuit is working with universal input voltage. In this paper, to make the design and implementation process easier, a simplified controller is proposed in the battery charger circuit which produces pulses according to the sign of the error of the feedback and which does not require any parameter. Since it is the most critical and restrictive case, charging mode of operation is addressed for the controller design. The simplified control is compared with conventional PI control in terms of performance, stability and robustness for universal input operation and the simulation results are supported with experimental verification.