PFC Converter with Three Phase and Single Phase Grid Compatibility and Integrated APD Circuit

This paper presents a Power Factor Correction (PFC) converter for onboard EV chargers that works with both single- and three-phase grid connections. The double line frequency power ripple, which skews DC output stability and may shorten battery life, is a major problem when operating in single phase mode. This problem can be solved by adding a power decoupling circuit to buffer the double-line frequency ripple power. Usually, large capacitor banks or LC branches are used to do this, which lowers power density. On the other hand, active power decoupling circuits are used to buffer the double frequency power into a secondary energy storage component through an active circuit. For single-phase operation the proposed solution employs a traditional three-phase Boost PFC converter, with the first two legs as an interleaved boost PFC converter and the third leg as an active decoupling circuit. Effective active power decoupling is achieved by controlling the energy storage components using the voltage ripple-based reference generation method. Analytical modeling is used to derive the conditions under which power decoupling is achieved and the phasor constraints for this. Simulation models are then used to validate the proposed scheme in closed loop mode.