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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TMC5160 stepper driver - one phase seems to be offset and clipped

I am using the TMC5160 stepper driver with a stepper motor. I am configuring it in SPI mode from an STM32F4. I used the sample commands from the datasheet on page 116 (section 23 getting started) with ...
1 vote
3 answers
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Confusion regarding sensitivity topic of closed loop system

I am reading about closed loop systems in Dorf, Modern Control Systems. While reading, I got confused by highlighted text in the attached snapshot. What does "variations in parameters" mean. ...
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Why is a step signal frequently used as a test signal?

Why do we use a step signal most frequently as a test signal in signal processing and control systems? What is the reason for not (frequently) using other signals? Especially in MATLAB and Simulink ...
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6 answers
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What are some of the examples of "plant" in control systems?

What is meant by "plant" in control system? This above question gives some detail about the term "plant" in context of control systems. But it mainly mentions "DC motor" ...
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1 answer
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How to increase the damping of a buck system?

I have designed a buck circuit. The Bode plot of my system is as follows: I use a type Ⅲ compensator to control my system. The switching frequency is 100 kHz. The cut-off frequency is 20 kHz and the ...
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1 answer
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Confusion regarding transfer function and state space conversion in MATLAB

I have values of my state space MATRICES(A,B,C,D). I implemented them in MATLAB. My code is below, but I got confused when I tried to convert my state space representation to transfer function, ...
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2 votes
1 answer
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One cycle control for PFC

Does anyone know how to build the resettable integrator in SIMPLIS or PSIM simulation? The figure below is from IRF I would like to do an OCC control for PFC, but I get into some trouble with how to ...
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1 answer
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FET voltage-controlled resistor schematics

I am trying to design and build a circuit that will accept a 1 to 5 VDC input and based on the voltage offer a 30 to 240 Ω resistance. I'd like the circuit to be linear. ie R = 30 + 210 x (Vin-1)/4 ...
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6 votes
3 answers
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Which would be better to control a 1 hp, 6 A water pump motor? Time relay or magnetic contactor?

Usually to control our water pump motor, we have to turn the switch on, wait for 15-20 minutes and then turn the switch off. Often times someone forgets to turn the motor off. I want the motor to turn ...
-1 votes
2 answers
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Can you sketch the step response of a transfer function like this using just pen and paper and a simple calculator?

I have a transfer function like this: $$H(s)= \frac{1}{10s^3+25s^2+10s+1}$$ If you have a transfer function that is composed of simple elements like P, I, D and second-order lag elements, you can find ...
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How to speed up precharging of the DC link capacitor of the three-phase inverter?

Let's say I have a three-phase inverter with a DC link capacitor of substantial capacity. I would like to charge the DC link capacitor to a DC voltage. One possibility is to use a resistor which is ...
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Can we say "transfer function" is almost same as black box, in context of mathematical modelling of physical systems?

In context of mathematically modelling of physical systems,can we say that representation of a system using "transfer function" form is almost same as black box form? Is it ok/correct? As ...
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Confusion understanding the term "classic control"?

I am trying to study basics of control systems, and I have came across terms like "classic control" and "modern control". These two terms "classic control" and "...
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How to calculate torque of a three-phase induction motor?

I have a three-phase induction machine with following nameplate data: \$V_{s_n}=\frac{425}{\sqrt{3}}\,\mathrm{V}\$ - effective value of the phase voltage, \$f_n=70\,\mathrm{Hz}\$ - nominal frequency, \...
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3 votes
3 answers
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Meaning of time parameters in control theory

I know in control theory there are different time parameters, but I'm not sure why they are used and defined that way, with my main doubts being about rise time; definitions from here: Delay time (td)...
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1 answer
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Relation of Eigenvalues with poles and zeros

I have modeled a system showing the following properties. It has some negative eigenvalues. All poles are placed in a left-half plane. Some zeros are right-half plane. In my knowledge, eigenvalues ...
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1 answer
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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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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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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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1 answer
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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?
0 votes
1 answer
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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 ...
0 votes
2 answers
58 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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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 ...
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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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4 votes
1 answer
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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 vote
2 answers
68 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,...
0 votes
1 answer
47 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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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
76 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 ...
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1 vote
2 answers
90 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 ...
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1 answer
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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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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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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 ...
0 votes
2 answers
160 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 ...
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2 votes
2 answers
147 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
156 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, ...
0 votes
2 answers
54 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,...
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1 vote
1 answer
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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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0 votes
3 answers
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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'...
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0 votes
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 ...
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 ...
1 vote
1 answer
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Nyquist plot mirrored across imaginary axis

I am reading Foundations of Oscillator Design by Guillermo Gonzales. When an amplifier is connected in a positive feedback configuration, the transfer function is \$A_{vf}(s)=\frac{A_v(s)}{1-\beta (s)...
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2 votes
3 answers
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Voltage is below 380

I am Vango from Ethiopia. Am junior electrical engineer. While working today I've faced some problem. That is when incoming voltage drops below 380 V, I mean when it is about 370 V, motor stops ...
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4 answers
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How to connect a bistable valve?

I need to control a bi-stable valve: Here is the typical wiring provided for such 3 wires type valve: But I don't want to continue to feed it when actually closed or opened which is normaly ...
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1 answer
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Why I am seeing 120 ohms resistance in obd connector Pin6 amd Pin16 and at ABS connector resistance between can+ and can- shows 60 ohms. Why?

I am seeing a resistance of 120 ohms between CAN high and CAN low at the OBD Connector between pin 6 and pin 14. I also checked the can bus resistance at the ABS/ESP module connector and it shows 60 ...
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0 answers
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BLDC Hall Sensor Angle Offset

I'm running a BLDC motor and I'm working on my own Software. I want to run the BLDC Motor with field oriented control, that's why I need a precise electrical angle. I'm using three hall sensors in the ...
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0 answers
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Lyapunov Theory to Prove that a Controller minimize the Control Energy or Actuation

Hello Control Engineers! I am currently trying to prove that certain controller actually tried to minimize the control actuation or energy, like utilizes less battery as compared to the classical ...
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1 answer
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TEC cold side temperature decreases, then increases rapidly [closed]

first post to this stack exchange. Self teaching on TEC circuits. I bought a diymore TEC1-12706 12V 60W 6A. Note no heat sink installed on the TEC. To test the TEC I put together a series circuit as ...
0 votes
1 answer
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Kiln SSR zero-cross frequency

I am planning on using a WATLOW DC2T-24C0-0000 power controller for a three phase electric kiln. It is a zero-cross 3 phase, 2 leg controlled contactor capable of driving 46 amps with its huge heat ...
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