Abstract:
In sound amplification, mostly in audio power amplifiers, the Signal to Noise Ratio (SNR) and
efficiency of the amplifier carries vital significance. In most switching devices, switching losses
and the parasitic voltage ringing cause problems at higher frequency spectrum. Higher order LC
(Inductor- Capacitor) circuit is used as a filter for removal of above mentioned issues by providing
us more attenuation at cutoff frequency resulting in improvements within total harmonic distortion
(THD) of an amplifier. The proposed control approach is based on two different sliding mode
controller types’ namely terminal sliding mode controller and arbitrary order sliding mode
controller. The controller uses capacitor current feedback and inductor current feedback for
proposed control law. The control laws are derived from Sliding surface equations for proposed
controller respectively. Differentiators are also used for the purpose of noise rejection using their
state approximation property. Simulations show that controllers outperformed according to
expectations with better results in the form of efficiency, SNR, and frequency response.
Performance of controllers in terms of resolving issues like overshoot settling time and steady state
error has been excellent. However, further improvements in terms of frequency response and
robustness of system, the addition of differentiator proved to be useful. This thesis also presents a
detailed comparison between proposed controllers, in terms of their distinctive features and
performance.
