Converters with a dc port and a single-phase ac port must store energy to buffer the inherent double-frequency power flow at the ac port. The minimum energy storage required to isolate the power ripple from the dc port is presented, and leads to the minimum capacitance required for converters that use capacitive energy storage. This paper presents a ripple power port to manage energy storage and decouple capacitor ripple from power ripple. A ripple power port allows the designer to make a choice of capacitor voltage independent of other system voltages. A combination of an ac link converter and a ripple power port leads to a dramatic increase in reliability: it is shown that converters with nominal ratings up to 200 W can be designed with expected mean-time-between-failure ratings on the order of 1.4 × 10 6 hsufficient for hundred-year operation in long-life applications such as photovoltaic converters and LED lamps. This large increase in life is achieved with minimal extra cost.

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As photovoltaic (PV) energy continues to gain market penetration, thanks in part to substantial cost reductions on the solar modules, attention is shifting to the balance-of-system performance and costs. This paper proposes an approach to explore the design limits of a module -integrated inverter by means of the component-level multi-objective optimization. A two-stage inverter along with an active filter to eliminate double-frequency content of the DC-link current is proposed for the topology of module-integrated inverter, and three candidate topologies were taken into account for the DC-DC stage. Efficiency, volume and reliability of the converters are taken as objective functions, and comprehensive component modeling is performed. Pareto frontiers reveal the limits of the system are illustrated, which help the designer to pick the most suitable topology and design for the entire converter. Experimental results show the validity of the modeling and optimization technique.

Design optimisation techniques for power electronic converters have been the subject of numerous research studies for the past 15 years. Accurate modelling is the most important task in the optimisation, and, because the nature of optimisation problem demands evaluating an objective function numerous times, fast and simplified modelling techniques are required. The objective of this study is to categorise and analyse the previous studies related to modelling techniques incorporated in design optimisation of power electronic converters. Common trends in modelling and optimisation of power electronic converters are analysed and suggestions for future research in this field will be presented.