Three-Dimensional Vector Cube Decomposition-Based Power Allocation for Multisource Inverter-Fed PMSM Drives

The multisource inverter (MSI)-fed motor drive is an attractive solution for hybrid electric vehicles. However, the design of the modulation scheme for the MSI is a challenging task since the desired motor control and the flexible power allocation between energy sources under unbalanced dc links should be realized simultaneously. In view of this, this article proposes a three-dimensional vector cube decomposition (3DVCD)-based power allocation strategy for the MSI to achieve flexible power allocation and desired motor control under unbalanced dc links. In the proposed 3DVCD scheme, the reference vector is synthesized in two symmetrical subcubes instead of the uneven three-dimensional voltage vector cube, which simplifies the modulation scheme with unbalanced dc links. By proportionally decomposing the reference vector as two subvectors and mapping them into two symmetrical subcubes, the additional degree of freedom of the power flow control of sources without affecting the motor control is obtained. Based on this, the power allocation between each source is realized by directly adjusting the decomposition factor of the reference vector. Besides, the theoretical power allocation range with the proposed scheme is analyzed. Experimental tests are conducted to validate the effectiveness and superiority of the proposed scheme.