Badea George-Cosmin Dr inż. Zdzisław Pólkowski Automation in electronics and telecommunication

Badea George-CosminDr inż. Zdzisław Pólkowski

Automation in electronics and telecommunication

http://www.momac.de/pop_el.html

Contents

1. Automatic control system ;

2. Classification SRA;

3. Synthesis of controllers P, PI, PD, PID continue;

4. The design dead-beat controllers;

5. The design regulators Dahlin;

6. Designing regulators with allocation poles method;

7. Automatic control for amplification and frequency;

8. Control power supply in switching;

9. Sources

Automatic control system

• SRA- Automatic system control;• The automatic control system is then automatically resize the output

control and closed loop are made so that in the steady:

Automatic control system

http://www.electrokoles.home.ro/auto%20web/05_Cap02-95.pdf

EP- prescribing elementEC- comparison elementR- automatic regulatorE- Execution elementM- measuring element


Classification SRA

Classification SRA

https://prezi.com/ekcw65td8bnq/clasificarea-sra/

1. After character aprioric information on IT:

a) SRA with complete pre-requisite information:• IT features are practically invariable in time.

b) SRA pre-requisite with incomplete information:• These characteristics change in a manner not known before.

2. After dependencies- steady state- between input and output sizes of components:

a) SRA linear:• When dependencies are linear.

b) SRA nonlinear:• When at least one of dependent is non-linear.


Classification SRA


3. After character signal processing: a) SRA continue :• When the all sizes involved are continuous in time.

b) SRA discrete:• When the least one of size has a discreet vibration in time.

4. After appearance time variation of input size:

a) Automatic control systems:• If the input size is constant.

b) Software systems:• If the size varies input is according to a particular program.

c) Tracking systems:• If input size varies randomly in time.


Classification SRA


5. By number of main loops:

a) A main loop systems;

b) Systems with several main loops or control systems.

6. Need for speed IT response to a signal being input:

a) SRA for fast processes:• IT’s time constans do not exceed 10.

b) SRA for slow processes:• When IT have the time constants large and often have a dead time.


Synthesis of controllers P, PI, PD, PID continue


http://www.shiva.pub.ro/PDF/TRA/slide_curs9_TRA.pdf

• In terms of automatic regulators continue constructive relies on the use of electronic amplifiers correction circuit provided input and feedback. Making laws by regulatory adjustment will depend on these two elements: amplifiers used and circuits correction.

• At continue regulators, in functional terms, input and output sizes are type continuously being made continuously addiction . Linear regulators performs a linear dependence between and . Linear regulators types are: P, PI, PD, PID.




1. Regulator with proportional action P•In this regulator, between the size of the input and the command it establishes a relationship of proportionality: ; where is the amplification factor of the controller.

• If areas of input-output variation differs, the proportionality is given by the relation:




2. Regulator with proportional-integral action PI• This type of controller is a combination of a proportional regulator and

one full. PI control law controller contains a term that is proportional action and a term P ensure integrator effect:

• The first form is the law regulating the type made by most industrial PI controllers:




3.Regulator with action proportional–derivative PD

• By using a PD controller is reduced during the transitional arrangements:

• Such a regulator introduces a proportional component, similar to that of the PI controller and a derivative component D introducing a proportionality between the last component output size and the drift of input sizes, . PD control law is expressed by:




4. Regulator proportional integral-derivative action PID

• PID controllers are some of the most complex industrial regulators, providing superior control performance. They capture the effects of proportional P, integral I and derivative D above, the law regulating:


The design dead-beat controllers

The design dead-beat controllers

http://lorien.ncl.ac.uk/ming/digicont/control/digital3.htm

• The dead-beat controller aims for the best response possible to a set point change. Qualitatively, this means that following a set-point change, and after a time period equal to the system time-delay, the output should be at set-point and remain there. This requirement is formulated as:

• Where k is the system delay, expressed as an integer multiple of the sampling interval Ts.• The system delay has to be at least one, because the system delay will include the unit delay due to the use of the sampler. At any particular sampling instant, the current state of the controlled output is sampled while at the same time, a control signal is sent to the process. • The dead-beat controller is therefore given by:

The design regulators Dahlin

The design regulators Dahlin


• Less exacting control can be achieved by making the closed loop behave like a first order plus time-delay system with unit gain, instead of following set point changes in the quickest way possible as in dead-beat control. That is we let:

• This is the z-transform of where will be set equal to the delay of the process being controlled. is the time-constant of the desired closed loop response and can be used as a tuning parameter to vary the speed of response. Substituting this into the synthesis Equation, we obtain the following controller:

• which is known as the Dahlin Controller.

Designing regulators with allocation poles method

Designing regulators with allocation poles method

http://www.engineering.upm.ro/master-ie/mse/mat_did/elen089/curs/C_1_4.pdf

• This method leaves from the general relationship: in which SRA transfer function is second order, ie:

• SRA design usually starts by placing poles dominant and in the left half-plane C in complex plan, which mainly determine performance SRA, so that in case of failure to satisfy performance requirements to be introduced additional poles and zeros.• The usual processes for more than two time constants (ef ≥2) is recommended for the position , next model:

Automatic control for amplification and frequency


http://www.radartutorial.eu/09.receivers/rx08.ro.html

1.a. Sensitivity Time Control (STC)• In radar receivers, the wide variation in return signal amplitudes make

adjustment of the gain difficult. Circuits used to adjust amplifier gain with time, during a single pulse repetition period, are called STC circuits, or “swept gain attenuator”.

• Sensitivity time-control circuits apply a bias voltage that varies with time to the IF amplifiers to control receiver gain. The Figure shows a typical STC waveform. When the transmitter fires, the STC circuit decreases the receiver gain to zero to prevent the amplification of any leakage energy from the transmitted pulse.



1.b. Automatic Gain Control (AGC)• Gain control is necessary to adjust the receiver sensitivity for the best

reception of signals of widely varying amplitudes. A complex form of automatic gain control (AGC) or instantaneous automatic gain control (IAGC) is used during normal operation.

• The simplest type of AGC adjusts the IF amplifier bias (and gain) according to the average level of the received signal. With AGC, gain is controlled by the largest received signals. When several radar signals are being received simultaneously, the weakest signal may be of greatest interest. IAGC is used more frequently because it adjusts receiver gain for each signal.



1.Methods for adjusting the amplification:

• The vast majority of radar receivers use different methods for adjusting the amplification. These methods generally acts on the amplification of one or more intermediate frequency amplification stages.

• The simplest method is the manual adjustment by the operator amplification. Other methods involve the use of special circuits which carry out an automatic gain control, depending on various factors.

• Classification:a) STC- sensitivity time controlb) AGC- automatic gain controlc) Log amp- logaritmic amplifierd) Dynamic Swept Gain



1.b. Logarithmic Amplifier• The logarithmic amplifier is a nonsaturating amplifier that does not

ordinarily use any special gain-control circuits. The output voltage of the logarithmic amplifier is a linear function of the input voltage for low-amplitude signals.

• It is a logarithmic function for high-amplitude signals. In other words, the range of linear amplification does not end at a definite saturation point, as is the case in normal IF amplifiers. Therefore, a large signal does not saturate the logarithmic amplifier; rather, it merely reduces the amplification of a simultaneously applied small signal.

• This sum produces an increase in the output even though the final stage is saturated. Detector 3 causes the output to continue to increase after the second stage saturates. The overall gain becomes less and less as each stage saturates, but some degree of amplification is still available. The proper choice of IF stage gains and saturation points produces an approximately logarithmic response curve.



1.b. Dynamic Swept Gain• Local clutter levels dictate the magnitude of swept gain and differing

requirements for swept gain are presented as the antenna rotates. Modern systems dynamically measure clutter levels for a large number of cells within the coverage area of the radar.

• These measurements are slowly adjusted to take account of changing clutter levels and used to set the swept gain attenuator to an appropriate level for the range azimuth cell currently being processed. In most cases, the values used are a variation on the normal static law.



2. Automatic Frequency Control

• The radar receiver requires a limited tuning range to compensate for transmitter and local oscillator frequency changes because of variations in temperature and loading. Microwave radar receivers usually use automatic frequency control (AFC) for this purpose.

• Classification:a) AFC in radio receivers;b) AFC in radar sets.



2.a. AFC in radio receivers• AFC circuits are used in situations where you must accurately control

the frequency of an oscillator by some external signal. The AFC circuit senses the difference between the actual oscillator frequency and the frequency that is desired and produces a control voltage proportional to the difference.

• A varicap is used to keep the IF stable. The varicap application here produces an apparent reactance, which is included in the oscillator frequency control circuitry. For example, let's assume the IF is 10,7 megahertz and the local oscillator (LO) is tracking below the incoming frequency.

• This variant of AFC circuits are used in radio receivers, fm transmitters, and frequency synthesizers to maintain frequency stability. It requires a relatively constant amplitude of the (received) input-signal. For pulse-radar sets this form isn't practicable therefore.



2.b. AFC in radar sets• Automatic frequency control circuits in a non-coherent or pseudo-coherent radar use two different but similar systems:a) The transmitters frequency readjust the receiver;b) The receivers frequency readjust the transmitter.

• The Local Oscillator is adapted to the actual line frequency in this wiring. As a second variant the control circuit can control the transmitters frequency instead of the LO frequency! In this case the transmitter-frequency would regulated to the more stable LO-frequency.

Sources

• http://www.electrokoles.home.ro/auto%20web/05_Cap02-95.pdf• https://prezi.com/ekcw65td8bnq/clasificarea-sra/• http://www.shiva.pub.ro/PDF/TRA/slide_curs9_TRA.pdf• http://www.creeaza.com/tehnologie/electronica-electricitate/Studiu-de-caz-privind-proiecta413.php• http://lorien.ncl.ac.uk/ming/digicont/control/digital3.htm• http://www.engineering.upm.ro/master-ie/mse/mat_did/ elen089/curs/ C_1_4.pdf• http://www.radartutorial.eu/09.receivers/rx08.ro.html• http://www.radartutorial.eu/09.receivers/rx11.ro.html• http://www.academia.edu/8283915/Surse_de_alimentare_in_comutatie




http://www.creeaza.com/tehnologie/electronica-electricitate/Studiu-de-caz-privind-proiecta413.php

http://www.creeaza.com/tehnologie/electronica-electricitate/Studiu-de-caz-privind-proiecta413.php






http://www.academia.edu/8283915/Surse_de_alimentare_in_comutatie

Documents

Badea George-Cosmin Dr inż. Zdzisław Pólkowski Automation in electronics and telecommunication