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This letter studies single-input dc-dc converter topologies that are suitable to be expanded into their multiple-input converter version. The analysis is based on several assumptions, restrictions, and conditions, including the goal of minimizing the total number of components and the use of at least one forward-conducting bidirectional blocking switch in each input leg. These conditions may affect the outcome of the multiple-input converter synthesis and lead to different configurations from those suggested before in the literature. Although simultaneous power delivery from all sources is not required, it should be possible to independently control the power drained from each input with some degree of freedom. The letter lists four rules that must be observed in order to be able to realize a multiple-input converter from its single-input version. These rules are used to identify the only feasible input cell that complies with all assumptions and conditions. Unfeasible input cells are also shown. The letter also identifies some additional feasible input cells if some of the assumptions and conditions are relaxed. These input cells are used to suggest several multiple-input converter topologies. Among them, six topologies, including versions of the single-ended primary inductance converter and the Cuk converters, are introduced through their circuit schematic. Index Terms--Converter realization rules, feasible dc-dc converter topologies, independent input power control, input cells, multiple-input converters.

This paper (also presented at [27]) presents an integrated design approach to small drives for emerging 42-V automotive systems. The emphasis is on motors for ancillary loads. The final result offers a simple and low cost solution with high efficiency and high power density. Motor and inverter designs are combined to gain advantages in power factor and operating range. A near-minimum-distortion method is introduced for the overmodulation regime to improve power factor without sacrificing harmonic performance. The design is addressed in several steps: integration of the induction motor into a 42-V environment, selection of the inverter modulation scheme, and final system integration. The proposed system consists of an induction motor wound for the proper voltage range and driven by an inverter. The inverter is used partly in the overmodulation regime when bus voltage is low. A signal is formed based on triangle injection to minimize distortion. Some alternative modulation approaches are also analyzed and compared with the proposed solution. Experimental results confirm that a low-distortion overmodulation approach can be implemented successfully. Index Terms--Automobile auxiliary loads, dc bus utilization, 42-V automotive power, induction motor, overmodulation, pulse-width modulation (PWM), three-phase inverter.