Step-Up and Step-Down Converter Integrated With Motor Inverter for Powertrain Applications

Motor inverter high-voltage regulation improves the system efficiency and reduces the dimensions of a permanent magnet synchronous motor (PMSM). This article presents an isolated inverter with step-up and step-down dc-link voltage regulation for an electrical vehicle powertrain system, which will improve the system performance in wide ranges of load and battery levels. Step-up and step-down converter and the motor inverter are merged into a single converter. Bidirectional and galvanically isolated energy transmission between battery and motor with reduced semiconductors number, easy control, and high efficiency are demonstrated. In addition, inverter transistors' RMS current results lower than in common solutions. Topology waveforms, devices losses, and zero-voltage switching (ZVS) condition are analyzed. Based on this study, a converter design procedure to meet main electrical vehicles requirements is proposed. Converter operation and design procedure are verified by simulation and experiment in two prototypes of 3.3 kW and 300 W.