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N. Dahl, N. Iversen, A. Knott, and MI. E.. Andersen, "Optimal Control of a High Frequency Class-D Amplifier," J. Audio Eng. Soc., vol. 66, no. 1/2, pp. 34-43, (2018 January.). doi: https://doi.org/10.17743/jaes.2017.0046 N. Dahl, N. Iversen, A. Knott, and MI. E.. Andersen, "Optimal Control of a High Frequency Class-D Amplifier," J. Audio Eng. Soc., vol. 66 Issue 1/2 pp. 34-43, (2018 January.). doi: https://doi.org/10.17743/jaes.2017.0046
Abstract: During the last decade, switch-mode audio amplifiers have become a common choice for audio applications because of efficiencies approaching 90% and distortions as low as 0.001%. Such amplifiers modulate the input audio into a high-frequency discrete signal that drives a Class-D power stage. The control loop is the key element in achieving high-quality performance. Modern control theory methods were used to design and simulate a full-state feedback integrating controller for use with a high-frequency bridge class-D amplifier. An optimal linear full-state integral controller based on the state-space model was designed using the Linear Quadratic Regulator (LQR) method, and verified on a linear and switching model. Measurements on a Class-D amplifier with the implemented controller showed that the step responses and THD+N measurements were aligned with theoretic predictions. A 30-fold reduction in THD+N was observed compared to open-loop. The results prove that the principals of modern control achieve good performance in Class-D amplifiers, even when the output filter has a large resonance.

@article{dahl2018optimal,
author={dahl, nicolai and iversen, niels and knott, arnold and andersen, michael a. e.},
journal={journal of the audio engineering society},
title={optimal control of a high frequency class-d amplifier},
year={2018},
volume={66},
number={1/2},
pages={34-43},
doi={https://doi.org/10.17743/jaes.2017.0046},
month={january},} @article{dahl2018optimal,
author={dahl, nicolai and iversen, niels and knott, arnold and andersen, michael a. e.},
journal={journal of the audio engineering society},
title={optimal control of a high frequency class-d amplifier},
year={2018},
volume={66},
number={1/2},
pages={34-43},
doi={https://doi.org/10.17743/jaes.2017.0046},
month={january},
abstract={during the last decade, switch-mode audio amplifiers have become a common choice for audio applications because of efficiencies approaching 90% and distortions as low as 0.001%. such amplifiers modulate the input audio into a high-frequency discrete signal that drives a class-d power stage. the control loop is the key element in achieving high-quality performance. modern control theory methods were used to design and simulate a full-state feedback integrating controller for use with a high-frequency bridge class-d amplifier. an optimal linear full-state integral controller based on the state-space model was designed using the linear quadratic regulator (lqr) method, and verified on a linear and switching model. measurements on a class-d amplifier with the implemented controller showed that the step responses and thd+n measurements were aligned with theoretic predictions. a 30-fold reduction in thd+n was observed compared to open-loop. the results prove that the principals of modern control achieve good performance in class-d amplifiers, even when the output filter has a large resonance.},}

TY - paper
TI - Optimal Control of a High Frequency Class-D Amplifier
SP - 34 EP - 43
AU - Dahl, Nicolai
AU - Iversen, Niels
AU - Knott, Arnold
AU - Andersen, Michael A. E.
PY - 2018
JO - Journal of the Audio Engineering Society
IS - 1/2
VO - 66
VL - 66
Y1 - January 2018 TY - paper
TI - Optimal Control of a High Frequency Class-D Amplifier
SP - 34 EP - 43
AU - Dahl, Nicolai
AU - Iversen, Niels
AU - Knott, Arnold
AU - Andersen, Michael A. E.
PY - 2018
JO - Journal of the Audio Engineering Society
IS - 1/2
VO - 66
VL - 66
Y1 - January 2018
AB - During the last decade, switch-mode audio amplifiers have become a common choice for audio applications because of efficiencies approaching 90% and distortions as low as 0.001%. Such amplifiers modulate the input audio into a high-frequency discrete signal that drives a Class-D power stage. The control loop is the key element in achieving high-quality performance. Modern control theory methods were used to design and simulate a full-state feedback integrating controller for use with a high-frequency bridge class-D amplifier. An optimal linear full-state integral controller based on the state-space model was designed using the Linear Quadratic Regulator (LQR) method, and verified on a linear and switching model. Measurements on a Class-D amplifier with the implemented controller showed that the step responses and THD+N measurements were aligned with theoretic predictions. A 30-fold reduction in THD+N was observed compared to open-loop. The results prove that the principals of modern control achieve good performance in Class-D amplifiers, even when the output filter has a large resonance.