Universal Bridgeless Nonisolated Battery Charger With Wide-Output Voltage Range

The existing onboard battery chargers (OBCs) are incompatible to adopt for different electric vehicle (EV) power-train configurations owing to different battery pack voltages and input power supplies. This letter proposes a new universal battery charger to charge EV batteries whose output voltage is ranging from 48 to 450 V. A dual-loop distinct current controller with a seamless transition for boost and buck operations is designed, which regulates the output voltage and maintains the unity power factor at the grid side. Furthermore, an active harmonic minimization method is incorporated with the designed controller to attenuate the prominent third-harmonic in the reference current and eradicate subharmonic oscillations. The performance of the proposed OBC is validated through the MATLAB simulations and experiments on a 1.5-kW laboratory prototype with an universal ac power supply and compared with existing OBCs.

Automated summary

This letter proposes a new universal battery charger for electric vehicles with a range of output voltage from 48 to 450 V. It features a dual-loop distinct current controller that seamlessly switches between boost and buck operations to regulate the output voltage and maintain unity power factor at the grid side. It also incorporates an active harmonic minimization method to reduce prominent third-harmonic in the reference current and eliminate subharmonic oscillations. The proposed OBC's performance was validated through MATLAB simulations and experiments on a 1.5 kW laboratory prototype with a universal AC power supply, and compared with existing OBCs.