Switch mode converters
AssigneeElectrotech Instruments Limited
InventorKeith H. Billings
Life of this patent
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Abstract
A magnetic amplifier which has a main winding and at least one secondary reset winding, and a core composed of amorphous magnetic material, the amplifier being arranged to operate at a frequency greater than 20 KH.sub.z. The invention also includes a switch mode converter which includes such a magnetic amplifier arranged to regulate the output of the converter by pulse width modulation.
Claims8
A magnetic amplifier having a main winding and at least one secondary reset winding, and a core composed of amorphous magnetic material, the amplifier being arranged to operate at a frequency greater than 20 KH.sub.z, wherein the amorphous magnetic material has the following characteristics measured at a frequency of 35 KH.sub.z :
- (i) a remanence ratio B.sub.R /B.sub.S greater than 0.7, where B.sub.R is the remanence and B.sub.S the magnetic flux at notional saturation;
- (ii) a post-saturation permeability .DELTA.B/.DELTA.H of less than 1000, when measured at a magnetic field strength of H=1 ampere turn per cm., where the flux B is measured in Tesla;
- (iii) a permeability .DELTA.B/.DELTA.H of greater than 50,000 when measured at magnetic flux B=0, using units of Tesla and ampere turns per cm.;
- and
- (iv) a coercivity such that the high frequency power loses of the core are less than 100 watts per kg of core material measured at a maximum flux of 0.4 Tesla.
A switch mode converter which includes a high frequency transformer having a primary winding in a primary circuit arranged to be energized by direct current and having means for switching the direct current at a frequency greater than 20 KH.sub.z, and at least one secondary winding included in a secondary winding circuit having means for smoothing and integrating the output of the secondary winding to provide a relatively smooth d.c. voltage and current at output terminals, wherein the primary circuit includes a magnetic amplifier arranged to regulate the output of the secondary circuit by pulse width modulation of the current in the primary circuit.
A switch mode converter which includes a high frequency transformer having a primary winding in a primary circuit arranged to be energized by direct current and having means for switching the direct current at a frequency greater than 20 KH.sub.z, and at least one secondary winding included in a secondary winding circuit having means for smoothing and integrating the output of the secondary winding to provide a relatively smooth d.c. voltage and current at output terminals, wherein the secondary circuit includes a magnetic amplifier arranged to regulate the output of the secondary circuit by pulse width modulation of the output of the secondary winding.
Dependencies are inferred from the claim text.