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This paper reports on a novel unipolar current excited control scheme for the asymmetric bridge converter (ABC)‐based switched reluctance drive (SRD), where the 3D space vector modulation under three modes is developed to reduce the total harmonic distribution (THD) and torque ripple. Firstly, two different 3D vector distributions, namely, the small voltage amplitude mode and large mode are presented based on the asymmetric converter. For both distributions, the zero‐sequence voltages generated by the effective vectors are considered. Additionally, zero‐sequence vectors (1,1,1) and (−1,−1,−1) are no longer treated as null vectors and involved in the control of zero‐sequence current. Then, the duty cycles of both two modes are obtained by the combination of the zero‐sequence and two adjacent active vectors. Moreover, based on the large modulation mode, a novel method combined with the small mode is proposed to further optimise the switching costs and torque ripples. The effectiveness of the proposed modes is verified through the simulation in MATLAB and the experiment on a dSPACE‐1103‐based prototype. Compared with the conventional switched reluctance motor vector control, the proposed scheme delivers better performances of THD, efficiency and torque ripple reduction.