--This paper derives general topological and electrical properties common to all lossless passive soft-switching converters with defined characteristics and proposes a synthesis procedure for the creation of new converters. The synthesis procedure uses the properties to determine all possible locations of the inductor and capacitor added to achieve soft switching. Then a set of circuit cells are used to easily add the additional circuitry to recover the energy stored in these elements. A family of soft-switching boost converters are given as an example of the synthesis procedure. Experimental waveforms are shown for a new soft-switching Cuk converter.

-A comparison study was conducted to characterize the loss mechanisms, component stresses, and overall efficiencies of a group of voltage-mode softswitching PWM methods including two newly developed methods. All soft-switching methods in the selected group allow zero voltage turn-on and turn-off of the main switch and utilize a single auxiliary switch with some resonant components. Advantages and disadvantages are identified for each method. Experimental verification for each soft-switching method are provided. It was found that not all the existing methods improved efficiency over most of the load range, but only those methods that softly switch the auxiliary switch, minimumize redirection current, and recover the auxiliary circuit energy.

-A comparison study was conducted to characterize the loss mechanisms, component stresses, and overall efficiencies of a group of voltage-mode softswitching PWM methods including two newly developed methods. All soft-switching methods in the selected group allow zero voltage turn-on and turn-off of the main switch and utilize a single auxiliary switch with some resonant components. Advantages and disadvantages are identified for each method. Experimental verification for each soft-switching method are provided. It was found that not all the existing methods improved efficiency over most of the load range, but only those methods that softly switch the auxiliary switch, minimumize redirection current, and recover the auxiliary circuit energy.

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Document VersionPeer reviewed version Link back to DTU Orbit Citation (APA): Smith, K. M., & Svendsen, S. (2016). The effect of a rotary heat exchanger in room-based ventilation on indoor humidity in existing apartments in temperate climates. Energy and Buildings, 116, 349-361. DOI: 10.1016/j.enbuild.2015.12 AbstractThe investigation constructed and simulated moisture balance equations for single-room ventilation with a non-hygroscopic rotary heat exchanger. Based on literature, the study assumed that all condensed moisture in the exhaust subsequently evaporated into the supply. Simulations evaluated the potential for moisture issues and compared results with recuperative heat recovery and whole-dwelling ventilation systems. To assess the sensitivity of results, the simulations used three moisture production schedules to represent possible conditions based on literature. The study also analyzed the sensitivity to influential parameters, such as infiltration rate, heat recovery, and indoor temperature. With a typical moisture production schedule, the rotary heat exchanger recovered excessive moisture from kitchens and bathrooms, which provided a mold risk. The rotary heat exchanger was only suitable for single-room ventilation of dry rooms, such as living rooms and bedrooms. The sensitivity analysis concluded that varying heat recovery or indoor temperature could limit indoor relative humidity in dry rooms when a moderate risk was present. The rotary heat exchanger also elevated the minimum relative humidity in each room, which could help to avoid negative health impacts. A discussion emphasized the potential benefits of selecting heat recovery to match the individual needs of each room. KeywordsDecentralized ventilation; single-room ventilation; room-based ventilation; rotary heat exchanger; moisture issues; mold risk; renovated buildings; energy retrofit; temperate climate. 2 Highlights• The simulated rotary heat exchanger provided moisture concerns in several rooms.• The rotary heat exchanger was only suitable for ventilation of so-called dry rooms.• Varying heat recovery or temperature can limit indoor relative humidity in dry rooms.• Single-room ventilation allows selection of heat recovery to match the needs of rooms. Nomenclature

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