A Space Vector Modulation-Based Sinusoidal Current Control Strategy for the Three-Phase Dual Active Bridge Converter

In most electric vehicles, there is a high-voltage system of around 200-450V to power the drive train and a low-voltage system to power the low-voltage loads. The three-phase DAB (3P-DAB) converter is one potential bidirectional topology that can be used to connect the two systems, due to its characteristics of inherent soft-switching and high-power density. A commonly used modulation scheme for the 3P-DAB converter is single phase-shift (SPS) modulation. On this basis, several modulation schemes have been proposed to extend the soft-switching range and minimize the conduction losses. However, almost all of the existing modulation schemes for the 3P-DAB are achieved by adjusting the phase-shift angle and duty cycle. Considering that the 3P-DAB converter is comprised of two three-phase two-level converters, space vector modulation (SVM) can also modulate the 3P-DAB converter, which can help to achieve sinusoidal transformer current waveforms with lower harmonics, and thus lower transformer losses. Hence, this paper presents an SVM-based sinusoidal current control strategy to achieve a circular trajectory of the current vector with lower harmonics. The feasibility of the proposed method is verified through simulation.