This paper proposes a new switching strategy for switch-mode power audio amplifiers that reduces the power dissipation in the switching devices of the power stage. The strategy is based on a thorough analysis of the loss mechanism and operating conditions of the power stage and how it relates to the audio input. The strategy utilizes a high-ripple current combined with full state control to improve soft switching capabilities. This shifts the losses from switching devices to the filter inductors, which are less sensitive to loss variations because of a larger form factor. Measured results on 100-W test amplifiers show that the proposed strategy reduces the power dissipation within the switches, causing up to 45°C temperature reduction locally in the switches and up to 35°C globally in the amplifier. THD+N levels are reduced to 0.03 % and power density of the implemented amplifiers is 6 W/cm3. Two amplifiers were implemented.
Iversen, Niels E.; Dahl, Nicolai J.; Knott, Arnold; Andersen, Michael A.E.
Affiliation: Technical University of Denmark, Kgs. Lyngby, Denmark
JAES Volume 66 Issue 12 pp. 1051-1061; December 2018
Publication Date: December 20, 2018
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