Switched Capacitor Based Voltage Boost Converter for Electric Vehicle Applications

A switched-capacitor (SC) voltage boost converter and its control methods for implementing dc-ac and ac-dc power conversion. The SC converter employs a switched-capacitor circuit augmented with the main converter circuit to the power source, thus providing unique features that cannot be attained by the traditional voltage-source inverter (VSI) or boost VSI. The additional features include doubling the area of the linear modulation region and eliminating both the large inductor in the boost dc-dc stage and the large filtering capacitor, which leads to a higher energy density and lower cost. The SC converter concept can be applied to all dc-ac, ac-dc, ac-ac, and dc-dc power conversions. To describe the operating principle and the control, we focus on one example: a bidirectional SC converter for dc-ac and ac-dc power conversion in electric and hybrid electric vehicles.