Design considerations in multi‐output DC‐DC converter with magnetic amplifiers

Abstract

The multioutput converter has the feature of fewer number of components and high efficiency. to produce more than one highly stabilized output, the corss‐regulation error should be compensated. to compensate the cross‐regulation error in the forward type multioutput converter, this paper proposes a circuit using magnetic amplifier. the circuit analysis is made to give the quantitative expressions for the cross‐regulation error and magnetic characteristics of the saturable reactor. Based on the relation between the dead angle and the temperaturerise of the saturable reactor, the relation between the number of turns and the cross section of the saturable reactor was derived in order to realize a satisfactory constant‐voltage control using magnetic amplifiers. Using the obtained relation, the design as related to the material properties of the saturable reactor and the conversion frequency of the converter is discussed. It is shown quantitatively that the core with a high saturated permeability and low iron‐loss should be used to miniaturize the saturable reactor and the amorphous core will be effective to miniaturize the magnetic amplifier by raising the conversion frequency.

Stabilizing magamp control loop by using an inner-loop compensation

“…Using the same circuit parameters and same crossover frequency requirements as ing to (6). Under this condition, a dominant-pole compensation can be used without risking system instability.…”