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The Operating Room (OR) is more and more equipped with surgical assist systems which make use of modern image acquisition and processing technologies. Within this scenario, the surgeon has to deal with a large amount of information which must be available at the right time and in the right place. This results in various real-time problems which must be addressed while building surgical assist systems. The components of such systems and their real time requirements are presented in this paper. Several concrete systems are presented and their real time properties discussed.

A prominent boost-type 3-level topology, which is proved to represent a cost effective and highly efficient solution for switched mode rectifiers is inspected towards its application at wide input voltage range and power line distorted conditions including single-phase supply. Supplementary measures for a low cost control scheme are described to facilitate the operation under these unfavorable conditions. Shutdown of e.g. telecommunication plants can thus be avoided, if a maximum power limitation is observed. The inherent adaptation of the control scheme to the largely varying supply conditions supports the high yielding efficiency at high output voltage, even when supplied out of two phases. Simulation and measurement results prove the maturity of this rectifier scheme.

A prominent boost-type three-level topology, which proved to represent a cost effective and highly efficient solution for switched mode rectifiers is inspected towards its operation at discontinuous conduction mode (DCM). This mode of operation occurs not only at high input voltage in conjunction with low load currents but even at medium loading in the vicinity of mains voltage zero crossings. Since the requirements on THD conflict with the actual behavior of the circuit when operated at DCM, measures are needed for optimization. After reviewing basic measures to avoid DCM the resemblance to three-phase/single-switch boost rectifiers is utilized to control the circuit. Novel measures to optimize the modulation scheme are proposed, facilitating the design of even smaller inductors, thus lowering costs. Selected simulation and measurement results prove the enhanced modulation scheme.