Dual-Inverter-Integrated Three-Phase EV Charger Based on Split-Phase Machine

Abstract

Significant effort has been dedicated to developing integrated onboard charging circuits for electric vehicles, aiming to improve cost, range anxiety, and charging convenience. The dual-inverter drivetrain topology has attracted particular attention as a platform for developing such solutions, being previously leveraged for the implementation of dc and single-phase ac onboard charging. This work proposes an integrated three-phase onboard charger based on the dual-inverter drivetrain. The proposed converter is implemented with minimal change to the dual inverter and no additional power electronics by introducing a split-phase electric machine. A mathematical model is developed, decomposing the system into four decoupled subsystems, individually responsible for charging, driving, grid common-mode current, and zero-sequence current generation, respectively. In light of this model, a novel space-vector pulsewidth modulation technique is introduced to ensure charging current control while generating no flux-producing, nor zero-sequence currents, and having superior common-mode performance. Simulation-based and experimental verification is conducted on a 7.2-kW scaled-down prototype to prove the charging concept, as well as the common-mode current elimination.