Modulation Waveform Split-Based Power Flow Control of Multisource Inverters

The multisource inverter (MSI) serves as a high-efficiency interface for hybrid energy electric vehicles by eliminating the need for intermediate dc–dc converters. Nevertheless, modulation design for the MSI is challenging as the motor drive on the ac side and power distribution between the energy sources on the dc side should be achieved concurrently. Besides, unbalanced dc port voltage of the MSI stemming from the direct energy storage integration leads to a heavy computational burden under the asymmetrical space vector diagram. Given this, this article introduces a modulation waveform split (MWS)-based power flow control for MSIs, aiming to achieve power flow control on the dc side and motor drive control on the ac side concurrently with easy implementation. In the proposed scheme, a carrier-based pulse-width modulation with third-order harmonic injection is utilized to address motor drive control on the ac side, and an MWS scheme under the virtual two-level inverter is proposed to achieve power flow control between the dc sources. With the proposed scheme, control objectives on both ac and dc sides can be met simultaneously in the carrier-based modulation framework, without the complexity of voltage vector synthesis under an asymmetrical space vector diagram. Besides, the power conversion efficiency can also be improved due to the discontinuous characteristics of the split-obtained duty cycle waveform. The steady-state and dynamic performances validate the effectiveness of the proposed method.