Dual Discontinuous PWM-Based Power Distribution Control of Multisource Inverters

The multisource inverter (MSI) is a promising topology for hybrid electric vehicles (HEVs) due to its advanced merits of single-stage power conversion from each source to the motor without dc-dc converters. However, it is challenging to design a modulation scheme for the MSI since it not only determines the output voltage on the ac side but also the power distribution between the sources on the dc side. Furthermore, the computation burden for the MSI is heavy due to its unsymmetrical distributed voltage vectors. Given this, this paper proposes a dual discontinuous pulse-width modulation (D <tex-math notation="LaTeX">²</tex-math> PWM) scheme to simultaneously realize power distribution and motor drive control for the MSI. In the proposed D <tex-math notation="LaTeX">²</tex-math> PWM, the MSI is decomposed into two independent sub-inverters, and modulation schemes of each sub-inverter can be implemented in symmetric space-vector diagrams, which avoids heavy computational burden under the unsymmetrical voltage vector diagram. Besides, the total switching times of 3 in the proposed D <tex-math notation="LaTeX">²</tex-math> PWM are realized by assigning the desired voltage vector for one of the sub-inverters aligned with the basic voltage vectors, which reduces the switching losses in this decomposed model and improves the current quality of the MSI. Comparative experimental results confirm the effectiveness of the proposed D <tex-math notation="LaTeX">²</tex-math> PWM.