Questions tagged [control]

Control refers to systems that control other systems, whether that be industrial machinery, lighting or devices used in a home

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Is it possible to plot this transfer function on MATLAB / GNU Octave?

I have to implement a transfer function such that $$H(z) = \sum_{k=0}^{N} \frac{B(z) - z^{-N} \: C(z)}{A(z)}$$ where \$A(z) = z^2 - 1.9 \: z + 0.98 \$, \$B(z) = z^2\$ and \$C(z) = -0.162126 \: z + 0....
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1 answer
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How to integrate action variables of logic type into the split range control structure?

I have following control task. I have to limit a current drawn from a source of power in a grid where I have following power consumptions: battery charger variable frequency drive aux power ...
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0 answers
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Need to change output voltage on MIC5891 driver

I have an LED control panel that uses the MIC5891 driver. I measured the VBB load voltage at 9.05 V, however, the outputs (1 through 8) all register at 1.96 V. What could be controlling this output ...
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2 answers
567 views

Single phase capacitor start induction motor TRIAC speed control and centrifugal switch replacement

I have a machine tool with a 1 HP reversible motor. I am looking at implementing speed control by using a zero crossing detector and phase angle controlling circuit. I am planning on using a micro ...
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1 answer
40 views

On-Time Control for Buck Converter

Can someone explain how they got equation 5.1. Why is the output voltage of their buck look like an equation for an non-inverting op-amp amplifying a Vref?
1 vote
3 answers
247 views

Solid State Variable AC

At work I often need a variable AC source and I usually use a large variable transformer which gives me anywhere from 1 to 300VAC. I do a lot of testing and was looking for methods to control the AC ...
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1 answer
28 views

How to control position and speed of a motor in Simulink?

I am trying to make a system that can launch a ball kind of like how a catapult would do. I'm going to be using an Arduino and an H-bridge with PWM but I'm not sure how I can control both speed and ...
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2 answers
54 views

Why does low DC gain move an integrator pole?

The author is describing a voltage-mode buck control loop. In particular, he is describing PI compensation. The line I have highlighted is where he mentions 'In the simulation results, the dominant ...
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0 answers
19 views

Flyback Converter Valley Switching and QR mode

I watched TI's basic flyback video about the different control methods. and I am confused about some things, please see mine below questions. 1.) Valley Switching and QR, last time I ask a question ...
2 votes
3 answers
2k views

Controller vs compensator?

Both these terms: controller(forexample PID controller) and compensator(Lead compensator) are often encountered in control systems,but what is difference between these two? Brain douglas in this ...
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2 answers
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Flyback Frequency Foldback Mode (FFM) and Skip Mode

I would like to know why flyback needs to use Frequency Foldback Mode (FFM) and Skip Mode. I did some research but I don't understand the details of what I've read. Below is a figure that I found in ...
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1 answer
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ZCD SIMPLIS function block questions

I find the figure which used to do the ZCD circuit. please see the below figure. Does anyone know what's name of U7? I can't find this module in SIMPLIS. I would like to use this way to do the ZCD, ...
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1 answer
222 views

How to control a proportional valve with an Arduino

I would like to know how to control a proportional valve (pvq13-5l-03-m5-a) with an Arduino. The valve operates with a constant 12 V and is driven by a current in the range of 0-170 mA. Could you help ...
4 votes
1 answer
102 views

Peak current mode control question

I read two different figures about the peak current mode control block diagram, and I am confused about one thing, please see the below two figures. In this figure, voltage loop output is connected to ...
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1 answer
749 views

How to find gain and phase crossover from a Nyquist plot?

Note: I need to do this by hand which is why I'm struggling. I'm only using MATLAB here to show the nyquist plot, and I was also using it to try and check my answer. Edit: There are poles at -50, -10 ...
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1 answer
347 views

How to make sure a clocked operation happens just once in Vhdl

title may be a bit confusing but what I try to do is to take data from ram/modify it and put that data back to the ram. I want all of this to happen just for the operation(Brightness/Contrast) time ...
1 vote
2 answers
67 views

Understanding voice voil actuator vendor specifications

I'm thinking of potentially using a linear voice coil actuator to move a 90g mass between 0 mm and 1 mm and back in the horizontal direction with a frequency of 20 Hz. Assuming triangular acceleration,...
3 votes
1 answer
745 views

Phase margin is 90° 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 op-amp (OPAMP in figure) with high ...
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1 answer
7k views

Find a point on root locus for specific damping ratio

Although I have seen many types of root locus plots which have some curved behavior, I cannot find the poles for which my system has a given damping ratio of \$ \zeta = 0.59 \$. I need to somehow find ...
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1 answer
369 views

Setting the initial output value for state space block in MATLAB

I've got the following control loop in Simulink: What I'm trying to do is to set the initial value for the output to be 23, right now it starts from 0 and I can't find any explanation how that's done,...
4 votes
1 answer
584 views

Modeling scalar control of PMSM

I have met with a scalar control algorithm for a permanent magnet synchronous motor. I haven´t heard about it before so I decided to develop a dynamic model to further analyze this control algorithm. ...
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1 answer
46 views

Small-Signal Modelling of Buck Control

In equation 3.7, why is the author using v_in and not v_in(s)?
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1 answer
719 views

Holding signal true for x seconds in LabView

I'm trying to create an automatic startup override system whereby when an ESD override button is clicked, a signal will be held true for 10 seconds overriding my ESD interlocks. This seems like there ...
3 votes
1 answer
301 views

Find transfer function and step function for this circuit

Can someone help me to find the transfer function of this circuit (i want to have the tension through the capacitor I think) and the step response in order to get the voltage in the function of the ...
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0 answers
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Adding variable speed control to 3-speed bldc pool pump motor

I have several 1.5 hp 240 V bldc pool pump motors I've repaired and salvaged from work with plans to re-purpose them on certain projects, an upgraded high torque motor for my mini lathe being a good ...
2 votes
1 answer
69 views

How can I use a microcontroller to trigger an existing capacitive-touch pad?

(Note: I have found several other questions on a similar topic, but none of them address my specific issue.) I have a lamp that is controlled by non-contact touch buttons. The user-facing surface is ...
0 votes
1 answer
477 views

Op-amp control theory

back at it again trying to use your genius brains. I have been trying to teach myself audio amplifier design. The big road block I am getting into is the control theory part of it, meaning how does ...
2 votes
1 answer
665 views

How to tackle noise with PI controller

Updated: I am not sure if the title fits my inquiry here but I will try to explain. I have this system show in Fig1. It is a simple plant \$\frac{1}{as}\$ (expressed in the frequency domain). Then I ...
1 vote
2 answers
78 views

How to drive 12V from a RPi GPIO?

I am building a smart lock and while the software and hardware parts are OK, the electronics part are an adventure for me. I have an old 230-12V power unit and I need to use it to power both a ...
0 votes
1 answer
48 views

What does it mean to have a settling time at 5% of final value?

I need to make my control system to have a tolerance of 5% in less than 0.5 seconds (settling time ts = 0.5s at 5%). My question is: does 5% mean the error band can be between these values in red (...
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58 views

Hard disk motor as a generator - controlling torque/rotation speed

I'm a mechanical engineer, currently working on a project concerning wind turbines: I want to use an hard disk spindle motor (4 pins) as my generator. Since I want to do wake experiments, I'd like to ...
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0 answers
26 views

Extra electric strike protection for access control system

I have an access control system with a linear power supply 230VAC/12VDC 5A that powers an electric bolt lock and an electric strike. When the exit button is pushed it cuts the power from the electric ...
11 votes
5 answers
3k views

What are the effects of removing P, I, and D from a PID controller respectively?

A proportional, integral, and derivative (PID) controller can feature three terms.) We sometimes see only two of the terms in use. For example, the derivative is disregarded for a PI controller. While ...
0 votes
2 answers
657 views

Limit MC-60 controller output

I am building a CNC engraver/Router. I have a Chinese 12-48 VDC, 400 W PM spindle. The spindle speed is from 3000 RPM at 12 V input to 12000 RPM at 48 V. I want to drive the spindle with a MC-60 ...
0 votes
1 answer
375 views

How can I get the viscous coefficient of friction B for a DC motor?

How can I get the value of B for a DC motor when the data sheet has Viscous Damping (F1) like the following?
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2 answers
92 views

Replacing a thermistor sensor with a common resistor to 'trick' it

Here's the catch: we have a device that has a sensor that helps shutting it down when air temperature is too high. This sensor is based on a thermistor. We are now switching to a more powerful cooling ...
0 votes
1 answer
234 views

Implementing quadratic linear regulator (lqr) in simulink

I am working with a non-linear model of a hot-air balloon. I have linearized the system, found the operating point, the state space matrices and I know these are correct:- ...
0 votes
1 answer
135 views

PID control with anti-windup time specifications

I have scoured the internet for a quite some time now and could not seem to find the answer to this. Is there a formula that approximates, with these specific gains (Kp, Ki, Kd, Kt), the rise time, ...
2 votes
2 answers
132 views

Synchronous Buck Converter - PWM modulation

Let's say that our Vin = 9V, Vout = 5V. Hence our duty cycle D = 5/9. Let's say that our switching frequency is 100kHz. Consider T_on as the time the HSFET is on. So our T_on in this case is: T_on = (...
0 votes
1 answer
519 views

Maintaining fixed shaft position of BLDC/PMSM

I intend to control the position and speed of a BLDC motor (still to be selected) using field oriented control (FOC) and an Encoder to determine shaft position and speed. From what I understand from ...
0 votes
2 answers
49 views

Using dual output LDO

I want to use this LDO: AP7346D-1828FS6-7. This LDO has two outputs and it has "Enable" controls. I want to connect these outputs 1.8V and 2.8V for one input. I can control this with EN pins,...
0 votes
3 answers
150 views

Current Sharing Circuit

I want to use this TI document to do the current sharing, about this document I have some questions I cannot get it. Could someone give some advice? I do not understand how this circuit works and why ...
2 votes
1 answer
308 views

Why do we ground the common probe on a 3 probe liquid level sensor?

I have a liquid level sensor with 3 probes, one us common, the other is for low level and the third is for high level. On the liquid level control relay diagram, I've noticed that the common probe ...
1 vote
2 answers
245 views

Larger phase margin means less overshoot?

Why is it that the larger phase margin means the system has less overshoot? I have heard that the larger phase margin means greater damping, but I don't how they are connected to each other. Could ...
1 vote
1 answer
51 views

Questions regarding analog compensator

Consider the following analog compensator for a DC-DC converter. Vo is the DC-DC converter. FB is the feedback voltage. Vref is the reference voltage. It is expected that $$ FB = V_o\frac{R_4}{R_4 + ...
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3 answers
137 views

Flyback CCM right-half-plane-zero and control question

The document Under the Hood of Flyback SMPS Designs, talks about the RHPZ effect. I have some questions about that. 1.) Why do we need to design in the low input voltage and maximum current? 2.) I don'...
3 votes
1 answer
1k views

How to plot Nyquist Plots?

By using the open loop transfer function for a control system, how would you then sketch the Nyquist plot by hand? I'm aware you'd substitute any \$s\$ term for \$j\omega\$ and then rationalise the ...
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1 answer
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Question on showing function in a control system block

I am trying to add a function to a control system diagram. I have a constant F being fed back into the diagram but it depends on a signal 'v'. In equations I directly used a signum function but for ...
1 vote
2 answers
2k views

Confusion calculating steady state error in MATLAB?

I am trying to use MATLAB to calculate steady state error I have found a weblink that gives code for finding steady state error but when i use that code i get value of steady error to be greater than ...
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what is the open and closed loop function of this system?

i found this in the text book. i solved by: 1- found the closed loop function of just the part of B(p) and its "feedback", let's call it B'(p). 2- after that i did H(p) = A(p) / ( 1 + A(p) * ...

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