Effect of PWM schemes on integrated battery charger for plug-in hybrid electric vehicles: Performance, power factor, and efficiency

Most eco-friendly vehicles can adopt a concept of an integrated battery charger (IBC), which utilizes a motor drive system for charging a high voltage battery pack. The IBCs inevitably require an additional boost inductor when the common mode inductance of the motor/generator (M/G) is too small to satisfy a condition for continuous conduction mode operation. In this paper, the IBC system with the additional boost inductor for plug-in hybrid electric vehicles (PHEVs) is analyzed and system performance according to the pulse-width-modulated (PWM) switching schemes, such as interleaved PWM scheme and synchronous PWM scheme, is discussed in terms of efficiency, power factor, and current distortion factor. Contrary to general multi-phase boost power factor correction converters, the synchronous PWM scheme results in a higher efficiency than the interleaved PWM scheme. The effects of the PWM switching scheme on the IBC system are experimentally demonstrated on a prototype, which consists of a hybrid power control unit for PHEVs and two interior permanent magnet motors.