Questions tagged [closed-loop]
The closed-loop tag has no usage guidance.
38
questions
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1answer
51 views
Open and Closed Loop Amplifier Circuit
For example, say that a system requires an input voltage of 5V, however, you only have a source that can provide 1V. The use of a voltage amplifier is obviously the solution to the problem. However, ...
0
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2answers
63 views
What is the significance of phase margin in an open loop amplifier?
I know the importance of phase margin to ensure stability in closed loop systems, but what about in open loop systems?
I am designing a regulated common based LNA IC that operates in open loop.
Can we ...
0
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1answer
54 views
What is the controlled variable in this particular case?
I have a question, maybe you can help me because I am not sure of the correct definition.
As an example I have a plant with a measured output y in a closed loop system. But as the feedback variable I ...
0
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1answer
58 views
closed loop pole of negative feedback
given w be the pole of open loop what in the pole of the closed lop shown bellow?
i have found axpression for GAIN but for the pole i am not sure.
Thanks.
-1
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1answer
74 views
Can a strong electric field generate an electric current within a closed loop of wire?
I would like to know if an electric current can be generated in a closed loop of wire by using a strong electric field to circulate the free electrons within the closed loop of wire.
Say that you have ...
1
vote
1answer
46 views
How to deal with controling force by positioning oscillating magnet?
I am trying to code up a closed loop control system on force generated by the paring of strong rare earth magnets. I do not have much experience with PID logic but i have a weak grasp of the basics (...
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0answers
38 views
Closed-loop position control with a stepper motor
Disclaimer: I understand this might not be the optimal setup for this application, but this is what I currently have available.
My controller is connected to:
a stepper motor with a lead screw for ...
0
votes
2answers
69 views
Can an open loop system replace a close loop system
I'm thinking about a mathematical possibility how an open loop system can replace a close loop system so here is my explanation
Let's say I have a plant with transfer function as given in image (1)
...
0
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1answer
55 views
What micro-controllers are suitable for a closed-loop DC Motor? [closed]
I am working on a small experiment on a closed loop DC motor for speed control.
The DC motor is separately excited and fed through a DC chopper.
I would like to know what are the best micro-...
0
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2answers
73 views
Closed Loop Transfer Function - PD Control
For the following control system, I am trying to find the characteristics of the system.
I have firstly found the closed loop transfer functions \$T(s) =\frac{C(s)}{R(s)}\$ , to be:
\$G(s) =K_p(s+9)...
0
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2answers
154 views
Closed Loop system with a second order dominated response on the verge of instability
I have the forward path transfer function of C(s)G(s) = K/s(s+3)(s+7) and want to find K so that it is second order dominated on the verge of instability.
But i'm not sure how to find it when it is ...
0
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1answer
191 views
Dominant Pole Approximation for loop gain
I have the following loop transfer function for a unity feedback system:
I understand that the \$(s+2)\$ term becomes \$2\$, but what happens to the \$s\$ ?
1
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1answer
306 views
Closed loop vs. open loop system analysis and design
I have found questions similar to mine in the forum but none were quite answered to my full satisfaction. I have two questions:
1) Why is controller design is traditionally done with the open-loop ...
1
vote
1answer
46 views
PID controller - should terms be completely independant?
I was under the impression that the P, I and D terms of a PID controller should be calculated independently of each other. That is, they would all use the same error information, but none of the three ...
0
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1answer
71 views
Closed loop equation initial value
I am doing math for a closed loop equation. I know the transfer function for a closed loop system is:
(Image copied from "Loop Gain and its Effect on Analog Control Systems" by Gabino ...
0
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1answer
130 views
Improve the performance of Buck Converter Loop Stability
The following are the specifications of my Buck Converter.
Input Voltage Range : 6V to 16V
Output Voltage : 5V
Switching Freq : 2.1MHz
Output Inductor : 22uH
Minimum Load Current : 200mA
Typical ...
0
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0answers
28 views
Drive signal (duty cycle) calculation for PI compensator
I am trying to simulate an inverter with 4 ideal switching devices in LTSpice. I have the compensator working, however I don't the correct equation in terms of calculating the duty cycle.
What I ...
0
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1answer
77 views
Dependent vs. independent current paths
Taking the following circuit:
The path on the left will be on and the same, whereas the path on the right is dependent on what is connected to the base of the transistor (not shown in the above ...
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0answers
48 views
Determining/Specing the proper stepper Motor
I am trying to properly spec a proper stepper motor for a project I am working on. I am attempting to provide roughly 3000 pounds of compressive force (about 13300 Newtons) using a p series NEMA 34 ...
0
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2answers
190 views
Confusion regarding root locus. Open loop or close loop?
Which transfer function ,open loop or close loop do we use/need as a pre req to perform root locus analysis?
I have also attached a snapshot of the relevant webpage of university of Michigan.
I have ...
5
votes
2answers
265 views
Circuit stable in the Bode diagram, unstable in step-response
I am designing a simple current control circuit and trying to simulate it in LT Spice. The circuit is not optimized for some real-world application, it's more a learning method for me to get grip on ...
2
votes
6answers
943 views
How does opamp open-loop gain affect closed-loop gain in a circuit?
The gain of an opamp circuit is basically $$A_v=-\frac{R_f}{R_i}$$
But how come the gain of the opamp itself does not appear in the equation? How is the opamp amplifying anything in the circuit? What ...
1
vote
2answers
98 views
Calculate closed loop gain with Oscilloscope measurements
Using these reading from Agilent MSO-X2012a oscilloscope:
from this circuit:
How do you calculate the close loop gain using these measurements. I already calculated by hand and got Av = 11V.
1
vote
1answer
322 views
Phase margin is 90 degrees but transient step response shows overshoot
The bode plot of the loop is as shown here
The transient step response looks like this
The block diagram looks something like this -
Basically a single stage opamp(OPAMP in fig) with high gain(...
0
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2answers
218 views
To prove that Close Loop transfer function is sensitive to perturbation in H(s) but not to perturbations in G(s)
The feedback control system with high gain K is shown in figure
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1answer
166 views
how to display an output variable from a speed sensor to a 7 segment display in C. DSPIC33E
I have just started an electrical engineering degree and been set an assignment to create a closed loop motor speed control system in C programming language.
The PIC is a DSPIC33E (BLO032) and the ...
2
votes
2answers
124 views
Proportional Control Balance Beam
Bit of an unorthodox question I'm sure, but I'm making a balance beam (two rotors on either end of a see saw) with proportional control, and I can't seem to get it to balance at 0.
The proportional ...
3
votes
1answer
125 views
What is the difference between 'x' and 'plus' symbol in the block diagram
Generally speaking, what is the difference between the 'x' and the 'plus' symbol in a closed loop block diagram?
For example, in
(https://ieeexplore.ieee.org/document/6983570)
, what's the ...
1
vote
1answer
323 views
SG3525 Closed Loop Inverter Waveform Problem
I'm using a sg3525 ic on a full bridge dc-dc converter in closed loop. The system is working fine, I don't have a problem with it. Output is just like what I want.
The problem is inverter part's ...
1
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1answer
193 views
Sample time of PI controller
I have designed a closed loop current control (PI controller) of a DC-DC converter in continuous time domain and it is working fine. The next task is discreetization of the controller and implement it ...
0
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2answers
629 views
Where does the negative sign come from in this transfer function?
I have a transfer function that was given to me. It's been a really long time since I've done block diagram math, so sorry if this is a newbie question.
Based on the block diagram below (I forgot to ...
1
vote
0answers
254 views
Implementing PID in PWM feedback to lower the settling time
I have created the following simple PWM feedback:
The step response is:
I have tried to add PID controller and I ran the following code to test it:
...
0
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1answer
109 views
Why doesn't current flow in the other loop?
I am just now learning about how transistors work, so please let me know if I have a misunderstanding.
I ran a simulation of the circuit drawn below, and the results were that current flowed only in ...
1
vote
2answers
122 views
Closed current loop control without H-Bridge, PWM
I am trying to find a way how to control the Voice Coil Motor (VCM) or PMSM motor with a closed current loop without the use of an H-Bridge & PWM.
Does anyone know how to make an analog closed ...
4
votes
2answers
254 views
Cannot predict closed-loop gain of this amplifier
This is the circuit I am currently analyzing: (link to LTSpice file)
I am trying to predict each stage closed loop gain and overall gain (with all loops closed).
First thing I did is calculate DC ...
0
votes
1answer
117 views
Find optimal gains transfer function
I have the following closed loop transfer function:
$$G(s) = \frac{K(s^2 + 200^2)}{0.05s^3 + (1+K)s^2 + 200{K_v}s + 200K}$$
Where \$K\$ and \$K_v\$ are gains.
My goal is to find the optimal gains ...
0
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2answers
139 views
Closed Loop control of a propeller
Hello I'm trying to control the velocity of the propeller with the pitch angle. I have a diagram from the factor cp over J and phi (see image: Draw.io diagram), but not a analytical formula.
J = v*60/...
2
votes
5answers
4k views
Understanding of Dominant Pole Compensation
According to Miller Effect, within amplifying devices such as transistors that have inverting voltage gain higher that one, there should be increased input capacitance with increased voltage gain of ...
