Creating bode plots using straightline approximations. Convert the phasors for the output components into time functions of various frequencies. Lectures 112 recitations 112 homeworks 17 homework 7 will not be collected or graded. Freely browse and use ocw materials at your own pace. Find materials for this course in the pages linked along the left.
Bel is a large unit and decibel db is usually used. In minimum phase system, how the start and end of polar plot are identified. Sketching straightline approximations of bode plots is a matter of following the straightforward approach outlined here, and the result is a plot that is very close to the actual frequency response of the circuit. Lecture examples of bodebased control system design.
In negative feedback, unstable conditions arise when closedloop gain a cl approaches. Nyquist stability theorem formally stated if p0 then stable iff no encirclements of 1. In both the plots, xaxis represents angular frequency logarithmic scale. Assume 0, the input pole frequency is lower than the output pole and zero frequencies, and all pole zero frequencies are well separated. Friends, check out the pdf ebook and notes for control system engineering for the students studying in electrical engineering branch. Bode plots page 1 bode plots a bode plot is a standard format for plotting frequency response of lti systems. Zahran another advantage is the ability to sketch using a simple method based on asymptotic approximation. Many common system behaviors produce simple shapes e. For the love of physics walter lewin may 16, 2011 duration. So, so far what we have done in the previous module was to learn how to design compensators and our main. Introduction to bode plot 2 plots both have logarithm of frequency on xaxis o yaxis magnitude of transfer function, hs, in db o yaxis phase angle the plot can be used to interpret how the input affects the output in both magnitude and phase over frequency. So, lets return back to the previous figure 4 ol bode plot below right, prior to solving for the second controller zero.
Bode plot is the graphical tool for drawing the frequency response of a system. September 6, 2011 control systems laboratory, iit kanpur page 31 32. Lecture 18 bode plot electrical engineering ee notes. Determine magnitude and phase bode plots for smallsignal voltage gain v outv in. Nyquist stability criterion, bode plots and stability margins in frequency domain. Lecture examples of bode based control system design example 1. The approximate bode magnitude plot of a minimum phase system is shown in figure. Page 1 nptel mechanical engineering modeling and control of dynamic electromechanical system module 3 lecture 25 introduction to bode plot introduction to bode plot d bi h kh bh tt h dr. So, it is called the bode plot it is also called the logarithmic plot. Design using bode plots lecture 01 introduction to design in the frequency domain hello. Becoming familiar with this format is useful because. Ramkrishna pasumarthy, department of electrical engineering, iit madras. Bode plot tutorial university of california, berkeley.
Niknejad bode plot overview z technique for estimating a complicated. Madan gopal, department of electrical engineering, iit delhi. Design oriented analysis our aim in design is to always keep the whole system view at hand so that we can alter some parts of the system and immediately see the results of the change in other parts of the system. Passive filters university of california, san diego. Increase in k necessary to scale plot to encircle 1. Bode plots versus root locus amit patel, student member, ieee, and gabriel a. Purpose the plot can be used to interpret how the input affects the output in both magnitude and phase over frequency. Chapter 6 frequency response, bode plots, and resonance. Control systems ebook pdf lecture notes download for. Nptel syllabus digital control system web course course outline. Agashe, department of electrical engineering,iit bombay. Ee40 lec 12 transfer function bode plots filterstransfer.
Smith bode plot overview zthen put the transfer function into standard form. Bode plot cant be used for stability analysis of non minimumphase system. Obtain the phasor for each output component by multiplying the phasor for each input component by the corresponding transferfunction value. At iit madras, the prerequisite courses are electrical and magnetic circuits and networks and systems. Lecture 41 polar plot and bode plots lecture 42 logarithmic scale for frequency lecture 43 asymptotic db gain lecture 44 compensating network.
Lecture notes of control systems i me 431analysis and synthesis of linear control system me862 department of mechanical engineering, university of saskatchewan, 57 campus drive, saskatoon, sk s7n 5a9, canada 6 3. Lec35 the nyquist stability criterion and stability margins youtube. Nptel mechanical engineering modeling and control of dynamic electromechanical system. So, we will call it as design in the frequency domain. It is represented by two separate plots, one is the magnitude vs frequency and the other one is phase vs frequency. Low q approximation for two pole ts often our two pole transfer functions have widely separated poles in frequency space allowing some nice approximate solutions to gs.
Last time we talked about the nonlinear response to dc voltage. Content in lectures 1 6 and 2029 will be relevant for this course. The exact curve can be obtained using some known corrections. Chapter 6 frequency response, bode plots, and resonance 3. Whereas, yaxis represents the magnitude linear scale of open loop transfer function in the magnitude plot and the phase angle linear scale of the open loop transfer function in the phase plot. Lecture notes of control systems i me 431analysis and synthesis of linear control system me862 department of mechanical engineering, university of saskatchewan, 57 campus drive, saskatoon, sk s7n 5a9, canada. Copyrights to these rest solely with the instructor and iit delhi. Nptel mechanical engineering modeling and control of dynamic electro mechanical system. Bode plots bode magnitude and phase plots topic wise questions in control systems from 1987 2003 1.
Bode plots are a simpler method of graphing the frequency response, using the poles and zeros of the system to construct asymptotes for each segment on a loglog plot. Bode plots bode magnitude and phase plots topic wise. Number of bels log10 p o pi or number of bels 2log10 vo vi because p v2. This ebook is very useful and can help you score really well during your exam. Download pdf of nptel material offline reading, offline notes, free download in app, engineering class handwritten notes, exam notes, previous year questions, pdf free download works best with javascript, update your browser or enable javascript. Bode plots a bode plot is a straight line approximation of h. From the last lecture we have noted how we can use the bodeplot for obtaining the frequency response of a system. They consist of the variation of the amplitude ratio log10 a and the relative phase versus the angular frequency log10 as discussed in the previous lecture, bode plots represent the steadystate response to sinusoidal excitation only. Bishakh bhattacharya professor, department of mechanical engineering iit kanpur joint initiative of iits and iisc funded by mhrd page 2 nptel mechanical engineering modeling and control. It is a standard format, so using that format facilitates communication between engineers.
The magnitude is expressed in db and the frequency is generally plotted in log scale. In this module we will learn how to use boded plots for meeting our design purposes. Lecture 5 bode plot lecture 6 lead compensator design using bode plot lecture 7 lag compensator design using bode plot lecture 8 laglead compensator design in frequency domain 6 deadbeat response design 03 lecture 1. Lecture notes feedback control systems aeronautics and. Control engineering online course video lectures by iit bombay. Analyze the system using bode plot and root locus techniques and suggest the relative. The operational amplifier is a directcoupled high gain amplifier usable from 0 to over 1mh z to which feedback is added to control its overall response. The q factor affects the sharpness of peaks and dropoffs in the system. Bode plots and decibel the ratio of output to input power in a twoport network is usually expressed in bell. The asymptotic bode plot of a transfer function is as shown in figure. Lecture series on networks,signals and systems by prof. Department of eecs university of california, berkeley eecs 105 fall 2003, lecture 3 prof.
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