The use conditions include two aspects: reliability and electromagnetic compatibility. In the past, only reliability was considered, but now due to the enhanced environmental protection awareness, electromagnetic compatibility must also be taken into account.
Reliability refers to the ability of a high-frequency power transformer to function normally until the end of its service life under specific use conditions. Generally, the use conditions that have the greatest impact on high-frequency power transformers are environmental temperatures. Some soft magnetic materials have relatively low Curie points and are sensitive to temperature changes. For example, manganese-zinc soft ferrites have a Curie point of only 215℃, and their flux density, permeability, and losses all change with temperature. Therefore, reference data at normal temperature (25℃), as well as at 60℃, 80℃, and 100℃, should be provided. Thus, the operating temperature of manganese-zinc soft ferrite cores is restricted to below 100℃. This means that when the ambient temperature is 40℃, the allowable temperature rise is below 60℃, which is equivalent to the temperature of Class A insulation materials. The manganese-zinc electromagnetic wire and insulating components that accompany the manganese-zinc soft ferrite cores generally use Class E and Class B insulation materials. Is it overkill to use Class H insulated triple-insulated electromagnetic wires and polyamide films? How much does the cost increase? Is it because the optimized design scheme of Class H insulated high-frequency power transformers can reduce the volume by 1/2 to 1/3?