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Fig. 2. "Average power models" of step-up, step down and "indirect" (or buck-boost) converters The "direct average current" (is the maximum possible common current, that would transfer the maximum possible "direct power" in a loop including the source and the load. That is, the minimum value of input and output currents, as illustrated in 0.b. Then, the "direct power" is the product of this current by the minimum of input and output voltages, as illustrated in (1). Consequently, P diff may be expressed as (2). The internal power (P int) processed by all the components of a power converter is in general higher than P diff (3), especially in isolated converters and most hybrid and SC converters. In general, the internal power is processed by inductors and capacitors, though the power processed by transformers need to be included in any design and optimization process, and in some cases, the power processed by capacitors is transferred in a resonan fashion, so it may be accounted for separately, as illustrated in (4).

We investigate with computer simulations the effect of applying an electric field on the water-to-ice transition. We use a combination of state-of-the-art simulation techniques to obtain phase boundaries and crystal growth rates (direct coexistence), nucleation rates (seeding) and interfacial free energies (seeding and mold integration). First, we consider ice Ih, the most stable polymorph in the absence of a field. Its normal melting temperature, speed of crystal growth and nucleation rate (for a given supercooling) diminish as the intensity of the field goes up. Then, we study polarised cubic ice, or ice Icf, the most stable solid phase under a strong electric field. Its normal melting point goes up with the field and, for a given supercooling, under the studied field (0.3 V nm) ice Icf nucleates and grows at a similar rate as Ih with no field. The net effect of the field would then be that ice nucleates at warmer temperatures, but in the form of ice Icf. The main conclusion of this work is that reasonable electric fields (not strong enough to break water molecules apart) are not relevant in the context of homogeneous ice nucleation at 1 bar.

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