Mapúa Institute of Technology School of Electrical, Electronics and Computer Engineering Feedback and Control Systems Laboratory ECE131L/B12
CONTROL SYSTEMS Module No.: 8 Understanding RLC circuits through MATLAB demos
Submitted by: Sapalaran, Ma. Carmela P.
Submitted to: Engr. Ernesto Vergara
Submitted on: September 3, 2015
Interpretation of Results Module 8 is about Understanding RLC circuits through MATLAB demos. In the MATLAB RLC Response Demo the four graphs shows the response of the system, initially it was set to low-pass parallel topology filter, then by increasing the resistance it affects the frequency response of the system because the amplitude increases, the poles moves to the right meaning the response approaches oscillation and becomes stable, the Nyquist graph widens. Varying the capacitance and inductance of the system also affects the frequency of the system because the amplitude phase, poles and Nyquist diagram also varies, it either increases or decreases. For a high pass, band pass, and band stop filters the resistance when it decreased the response is stable and fast; when it is increased the response is less stable and slow. For inductance when it is decreased, the response is less stable and slow; when it is increased the response is stable and fast. For capacitance when it is decreased the response is stable and fast and when it is increased the response is less stable and slow. When the topology was changed for the high pass, band pass and band stop filters, for resistance when it is decreased, the response is stable and fast; when it is increased the response is very fast. For inductance when it is decreased the response is very fast and stable; when it is increased the response is fast but less stable.
For capacitance when it is decreased the response is very fast but with overshoot; when it is increased the response is fast and stable. The advantage of series or parallel topology in the implementation of filters using RLC circuits is it give more reliability of passing or rejecting certain signals since L and C are frequency dependent while the disadvantage is the component RLC depend on each other making the system susceptible to variation. The pole-zero-map, step response, bode plot, and Nyquist plot are related to each other because they show the stability of the system. They can determine the location of the poles in the pole-zero-map, the number of closed and opened loop poles in the Nyquist diagram and frequency with data it the Bode plot. Through transfer function we can know the response of the system given the variables at the numerator of denominator.
Conclusion: Upon the completion of this module I’ve learned that there are different types of analog filters which are the high pass filter, low pass filter, band pass filter, and band stop filter. A high pass filter accepts signals of high frequencies and rejects those of lower frequencies. A low pass filter accepts signals of low frequencies and rejects those of higher frequencies. A bandpass filter accepts signals at middle frequencies and rejects those outside the range of middle frequencies. A bandstop filter accepts signals outside the middle frequencies which means it is the opposite of the bandpass filter. Analog RLC filters have can be any of the two topologies its either series or parallel.
