A Composite Converter with Reduced Power Electronics for Electric Powertrain Applications
Résumé
This study proposes a composite converter for electric powertrain applications, which integrates the functionalities of a boost converter and a variable speed drive with reduced power electronic devices. By utilizing the neutral point of traction motor, the potential of zero-sequence circuit of traction drive is unlocked, thus enabling an equivalent boost and achieving internal dc/dc power conversion bidirectionally. Theoretical analysis and equivalent circuits are presented to explain the principle of the composite converter. A modified field-oriented control strategy with an augmented zero-sequence control-loop is proposed to regulate the dc-bus voltage and the traction motor simultaneously. Experimental validations are carried out on a 1.2 kW permanent magnet synchronous machine traction platform to verify the effectiveness. Compared to a classic two-stage converter, the total efficiency can be improved by 3.1-3.4% due to the reduced switching losses.