Magnetic element in a non-saturated region in a transformer/inductor

Abstract

Single, multistage, and distributed magnetic switched and tank resonant power conversion systems can use a transformer with a magnetic element operating in a non-saturated region (NSME). The NSME provides superior protection to conducted lightning transients, superior thermal operating bandwidth, higher magnetizing efficiency, greater flux / power density potential and form factor flexibility when implemented with many circuit strategies, some of which are disclosed herein. Efficient energy storage and transfer is achieved by the optimized application of NSME. The use of efficient rectifying flyback management techniques protects switches and provides additional output. The preferred embodiment teaches against common theories of transformers and uses a NSME in the core.

Description

CROSS REFERENCE APPLICATIONS [0001] This application is a divisional application of application Ser. No. 09 / 923,027 filed Aug. 6, 2001 which is a divisional of application Ser. No. 09 / 410,849 filed Oct. 1, 1999 and issued as U.S. Pat. No. 6,272,025 on Aug. 7, 2001.FIELD OF INVENTION [0002] The present invention relates to converters, power supplies, more particularly, to single, or multi stage, AC / DC or DC / DC isolated and non-isolated push-pull converters including but not limited to, forward, flyback, buck, boost, push pull, and resonant mode converters, and power supplies, having individual or distributed NSME with high speed PET switching and efficient flyback management and or having input PFC (power factor correction) and input protection from lightning transients. The invention also allows the magnetic element(s) be distributed to accommodate packaging restrictions, multiple secondary windings, or operation at very high winding voltages. BACKGROUND OF THE INVENTION [0003] Ther...

AI Technical Summary

Benefits of technology

[0021] Another aspect of the present invention is to provide protection from high voltage (input line) transients.

Problems solved by technology

The push-pull approach makes efficient use of the magnetic element by producing AC bias, but suffers from high parts count, thermal derating, oversized magnetics, and elaborate core reset schemes.

In addition to the aforementioned issues the forward converter suffers from inefficient (dc bias) use of the magnetic element.

The magnetics of the prior art power supplies are generally designed for twice the required power rating and require complex methods to reset and cool the magnetic elements resulting in increased costs and limited operating temperatures.

This is because high permeability magnetic elements saturate during operation producing heat in the core, which increases permeability and lowers the saturation threshold.

This produces runaway heating, current spikes and / or large leakage currents in the air gap, reduced efficiency, and ultimately less power at higher temperatures and / or high load.

The overall effects are, lower efficiency, lower power density, and forced air / heatsink dependant supplies that require over-rated ferrite magnetic elements for a given output over time, temperature, and loading.

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