# 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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### Controls - seeing if a discrete time system can arrive from a certain input to a certain output

Given a system: $$A = \begin{pmatrix} 7 & -3 \\ 18 & -8 \end{pmatrix} \quad B = \begin{pmatrix} -2 \\-6\end{pmatrix} \quad C = \begin{pmatrix}1 & 0 \end{pmatrix} \quad D =0$$ I need to see ...
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### Basic Buck Converter Analog Control Circuit [closed]

I am trying to design a 5 V -> 3.3 V buck converter as a design exercise and am implementing my own analog control circuit. At the moment I am not considering compensation or loop response as I am ...
1 vote
95 views

### Connecting the LC circuit to dc voltage source without transient

Let's say I have following circuit where the transistors are controlled via a software in the microcontroller. I have been looking for a control algorithm how to achieve a state when both of the ...
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### Simplest Peltier Control

I wish to control the delta-T across a Peltier module using constant voltage and variable current. If efficiency is not an issue, can I just wire a potentiometer in parallel with the module? I ...
35 views

### Need help understand phase shift control in SPS dual active bridge converter

I am trying to understand the control scheme of the phase shift controller in a dual active bridge (DAB) converter. I initially started with the built in PLECS DAB converter and understood all the ...
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### How can a system's overall transfer function be the same if the poles are different?

I am working through a problem that gives a block diagram representation of a physical variable state space. It then asks to build the state system for that physical variable system and a phase ...
56 views

### Wifi LED Smart Bulb

I'm trying to use my smart wifi bulb ESP8266 as a wireless controller for RGB LED. Currently it's a 9 W bulb works from 220 V AC. My question is, if I disassemble the ESP8266 board from it and use it ...
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1 vote
46 views

### Speed control fan with PWM and capacitor (no pwm fan)

For my project I want to control the speed of a regular non-PWM fan. I was wondering if what I came out with is a good idea or not. I noticed that the capacitor I used (25V 47µF) gets a bit warm after ...
41 views

### measuring NI 9215 for measuring pressure using pressure transducer

I need to measure pressure using pressure transducer with output of 0-10 V & 0-10000 psi range and NI 9215. How could be the code?
21 views

### Using Integral of Error as Input in Fuzzy Logic Controllers

I'm currently working on a control system for a doubly fed induction generator (DFIG) as part of my thesis project. Traditionally, fuzzy logic controllers (FLCs) use the error (e) and the derivative ...
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### Trying to understand (and mimic) the multimeter's interference with a circuit

I am trying to use a microcontroller to regulate the speed control of a sewing machine, rather than the foot pedal that normally serves this purpose. The pedal cord has 2 wires that connect it to the ...
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48 views

### Current mode control or voltage mode control of flyback converters [closed]

What is used more nowadays - current mode or voltage mode control when considering flyback converters?
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### Plotting the bode plot of a high pass filter using matlab

I am trying to theoretically find the frequency response of the circuit given below: Firstly i found the impedance value of the RC Ladder by applying the equation below, then i defined this as "...
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### How does "pass band" relate to the response speed of a digital controller?

I am reading the page 318 of "Digital Control Systems: Identification, Design and Implementation" by I. D. Landau and G. Zito, which talks about the choice of desired performances in digital ...
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1 vote
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### Using Buck-Boost as LED driver

I am trying to use a buck-boost controller like LT8390 as a LED driver. This controller can act as a current controller if the current through sensing resistor connected to (ISP/ISN) can be adjusted. ...
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66 views

### 25A SSR Failing

I have a 25A soild state relay I'm using to control a boiler. Using a SSR-25 DA https://cdn.sparkfun.com/datasheets/Components/General/SSR40DA.pdf. The issue I have is that if I supply 12v to the ...
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### Confusion about finding poles by inspection

I have a few doubts regarding finding poles by inspection and why sometimes the 'quick, intuitive' techniques do not work. Question 1 Consider the circuit shown in figure 1 below: By manually writing ...
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### Multi-loop systems block reduction techniques

Do I start by multiplying 18/s+3 * 1/s+3 = 18/(s+3)^(2)? Then is it (18/(s+3)^(2))/(1+(18/(s+3)^(2)*4)) = 18 / ((s + 3)^2 * (72 / (s + 3)^2 + 1))?
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### PMSM - RMS phase current as a function of Id and Iq

Assuming to have a 3-phase PMSM driven with a balanced system of currents with sinusoidal shape, is there a way to write the RMS phase current as a function of Id and Iq? I want to use the RMS phase ...
1 vote
93 views

### How to obtain the pole zero map and step response of the 2nd order system and determine the mode of damping in the system using MATLAB?

$$\frac{C(s)}{R(s)}=\frac{\omega_n^2}{s^2+2\zeta \omega_n s+\omega_n^2}$$ Obtain the pole zero map and step response of the 2nd order system and determine the mode of damping in the system. If the ...
171 views

### Kalman filter for estimation of braking resistor temperature

Let's say I have an inverter fed three phase induction motor drive where in the braking phase (when the motor operates in a generator mode) the generated electrical power is dissipated in the braking ...
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### Solenoid valve gating and time proportional control

I'm trying to complete this simple task: I have solenoid valves to control the humidity in an array of boxes. I use time proportional PID control to turn them on or off. I suspect I keep wearing them ...
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### How can a power converter small signal model predict transient behaviour during a load step which is a large signal disturbance?

I see small signal model being used to predict the Overshoot/Undershoot of output voltage due to a load step. How do we justify this approach, since the basic assumption of small signal modelling is ...
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### Reference Voltage Tracking for DC-DC boost converter

I have a boost converter which works perfectly with an s-domain controller (using a type-3 compensator and dual loop). Now, I need to do this using digital control (z-domain). I have converted the s-...
61 views

### Design a PID controller for a MG=1.5

Consider the following system: I need to design a PID controller with a gain margin of 1.5 for the disturbance P(s). In order to have a certain gain margin I need to find the critical gain Ku, so ...
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### Dual 4-20 mA inputs to voltage ramp

I'm trying to take dual 4-20 mA signals and use them as a heat/cool signal for a Peltier module. I have an integrator but I'm trying to find the best way to decipher the dual signals and turn them ...
106 views

### PCB layout/schematics of solenoid lock control - Problem - uncontrollable unlocking

I have a problem with opening solenoid locks. Sometimes, immediately upon connecting the power, and other times after about half an hour or even an hour, the locks start to open uncontrollably. I have ...
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1 vote
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### How do I find my phase margin using the Bode plot?

From the Bode plot, is my phase margin correct? I estimate around +30 degree phase margin - or is it -30 degree phase margin? I am unsure about this thing.
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### Can a MOC3032M optocoupler be used to generate a DC PWM signal?

I'm trying to make a circuit that can output an 80 Hz PWM signal. I'm planning to use an Arduino to switch an optocoupler that will control the duty cycle. Here is my circuit: After building the ...
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### Reflow oven control technique

I am developing a DIY reflow oven using a 10L common electric oven with quartz heating elements. Below is a graph that represents the oven's step response (open loop response): In blue: oven's step ...
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### Zener diode as a switch

I would like to use a Zener and a NPN transistor as a voltage switch to close a 12 VDC relay. My thought was 12 V zener to the base to turn on the transistor and close the relay when supply is above ...
496 views

### Is it wise to determine heating element temperature from resistivity?

Context I'm making an electric furnace for melting metal, and aiming to make my own controller. Everyone seems to just use thermocouples and a control loop, I thought perhaps I could just measure the ...
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### Can anyone point me in the right direction to solve this control systems problem?

The problem is the one at the top of the page. I was able to reduce the first block diagram into the feedback loop block and I got H(s) = 4s + 1 using the identities in the book. I've spent hours ...
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1 vote
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### Allowable process variation for non minimum phase plant

Scenario (plant model subject to process variations) Consider a plant $P(s)$ in series with a controller $D(s)$ with a negative feedback path around it, where the closed loop is given by the ...
114 views

### Connecting every other DIN terminal to each other

I am building a custom panel. My output DIN terminals are supposed to be in this order: Power, Ground, Power, Ground, Power, Ground.... I cannot find a proper way (jumpers or bars) to connect them. ...
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1 vote
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### Control engineering: how to design a system for desired impulse response

I've designed a system to get a desirable step response. However, I think the impulse response of my system is more important. There are many methods for designing a system for transient response ...
207 views

I have a circuit to control a small motor which is modelled in Falstad. See model below. when I start the simulation the voltage on the MOSFET side of the motor is low and then climbs until it reaches ...
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### Relation between controllers and compensators?

https://www.control.utoronto.ca/people/profs/kwong/ece311/2018/lecture_notes/lead_or_lag.pdf Please check the above link especially the lines shown highlighted in attached snapshot. So can we say that ...
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### How does a voltage controller (outer loop) set the current reference for the (inner) current loop in cascaded control of a boost-converter?

I am currently trying to understand the cascaded current-voltage control of a boost converter (and later design the PI-controller). Let me summarize the information I have collected so far: Outer (...
1 vote
206 views

### How can I implement current control for proportional valves?

I am currently working on operating a proportional valve for airflow, but I am facing some challenges. Initially, I attempted to control it using a DRV8871 motor driver with PWM frequencies of 500 Hz, ...
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1 vote
155 views

### How to reduce gain margin to finite value?

I am trying to observe bode plots for a system but i am getting infite gain margin. I know that positive phase margin and/or positive gain margin represent stable system while negative phase margin ...
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### I don't understand this temperature controller circuit's behaviour [duplicate]

I am trying to build a circuit to regulate temperature for a few microheaters. Here's the circuit I am using: This is a constant temperature controller circuit often found in the research papers and ...
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### How to vary output current by maintaining constant output voltage? [closed]

I want to control a proportional valve by keeping its voltage constant while varying its output current. Is there any way to achieve this
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### Can an RCL circuit be asymptotically unstable? If so, what does that mean physically?

I'm analyzing the asymptotic stability of the system of ODEs that comes from an RCL circuit in series. Below is my circuit, with battery voltage $u(t)$, resistor with constant $R>0$, capacitor ...
1 vote
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### Why doesn't the LED shut off?

Why doesn't the LED doesn't shut off when I set the input to 0V? The simulation does, but that's not what happens in the real circuit. I've grounded the second op amp's inputs (on a NE5532), tried ...
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### BLDC motor position control

For my project, I need to control position and speed of a BLDC motor with PID. Although there is information about the speed control of the motor, I could not find much information about the position ...
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### Rexroth Indramat CLM 1.3, how to execute command

I have to execute the command: CLA Clear Axis (Absolute Encoder Value) E 0170 CLA 2 To be honest I don't know how the CLM works ...
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### For the equation below, how would I calculate the gain required for a settling time of 1 s?

The equation is: $G=\dfrac{k(s+4)}{(s+1)(s^2+6s+13)}$ How would I calculate the gain (k) required for a settling time of 1 s? By using $ts=\dfrac{4}{(ωζk)}$ the closest value I got was ...