1 / 14

SUPERCONDUCTING VOICE COIL – A ROUTE TO INCREASE EFFICIENCY OF AN ELECTRODYNAMIC LOUDSPEAKER

SUPERCONDUCTING VOICE COIL – A ROUTE TO INCREASE EFFICIENCY OF AN ELECTRODYNAMIC LOUDSPEAKER. Ivan Djurek *1 , Danijel Djurek *2 , Branko Somek *1 *1 Faculty of EE and Computing, Zagreb, Croatia *2 AVAC, Zagreb, Croatia. INTRODUCTION. Complex system Several steps of energy transformation

kaili
Télécharger la présentation

SUPERCONDUCTING VOICE COIL – A ROUTE TO INCREASE EFFICIENCY OF AN ELECTRODYNAMIC LOUDSPEAKER

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SUPERCONDUCTING VOICE COIL – A ROUTE TO INCREASE EFFICIENCY OF AN ELECTRODYNAMIC LOUDSPEAKER Ivan Djurek*1, Danijel Djurek *2, Branko Somek *1 *1Faculty of EE and Computing, Zagreb, Croatia *2AVAC, Zagreb, Croatia

  2. INTRODUCTION • Complex system • Several steps of energy transformation • Loss of energy • Hard to construct the loudspeaker with low distortion level and high efficiency • Possible route: SC voice coil

  3. CONVENTIONAL LOUDSPEAKER • Example of forced damped oscillator • M – mass of voice coil and membrane • RS, XS – real and imaginary part of emission impedance • k – elastic restoring force • RM – friction part

  4. CONVENTIONAL LOUDSPEAKER • Emission impedance • Imaginary part represented with aproximation of Struve function [3]

  5. CONVENTIONAL LOUDSPEAKER • Characteristics of used commercial loudspeaker Manufacturer data

  6. CONVENTIONAL LOUDSPEAKER • Current from back electromotive force (BEF) • Driving force • Amplitude of oscillation

  7. CONVENTIONAL LOUDSPEAKER • Amplitude at resonant frequency

  8. CONVENTIONAL LOUDSPEAKER • Total power • Efficiency

  9. CONVENTIONAL LOUDSPEAKER • Efficiency of used commercial loudspeaker

  10. LOUDSPEAKER WITH SC VOICE COIL • Changes: • One turn in voice coil: l = 0.075 m • RC = 0 W • No inductance - L • Total mass (calculated): 11 g

  11. LOUDSPEAKER WITH SC VOICE COIL • Efficiency

  12. EXPERIMENTAL • Test of previous calculations • Copper voice coil cooled to 130 K (-143°C) • Vibration amplitude vs resistance of voice coil

  13. EXPERIMENTAL • Amplitude and resistance measurements f=40 Hz

  14. DISCUSSION • Advantages: • Disappearance of electro-mechanical coupling terms > lower distortion • Reduction of voice coil inductance L • Reduction of mass • Higher efficiency • Problems: • Impedance matching between SC loudspeaker and common amplifiers • Cooling

More Related