Design and Operation of a Three-Phase Split-Source Inverter with a Saturable Inductor

In low-voltage-fed applications, single-stage inverters with buck and boost capabilities represent an appealing alternative to conventional voltage source inverters that require an additional boosting stage and, hence, imply higher cost, complexity, and volume. Among the available single-stage topologies, the recently proposed split-source inverter (SSI) offers several advantages over its competitors (e.g., the ability to employ conventional pulse-width modulation (PWM) schemes, constant voltage across the bridge, etc.). This paper examines the impact that the inductor's magnetic saturation can have on the design and operation of an SSI. The theoretical considerations are first presented using the test data of an actual saturated inductor. Four PWM schemes - two biased and two unbiased - are included in the analysis. A laboratory setup has been constructed for evaluation of the considered impact. The obtained results demonstrate that the inductor current ripple may be significantly underestimated if magnetic saturation is neglected in the SSI design.