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40 Threads found on Voltage Controlled Pwm
Hi folks, I am currently learning the bldc motor drive. I am not understanding how changing the terminal voltage across the motor affects the motor speed. As per my knowledge the speed depends only on the frequency at which we are energizing the coils. But using pwm we are not changing the rate at which the three coils are energ
Hi everybody, I am currently trying to build a converter model for a DFIG. To get a faster computing time i want it to be in a state space model system. so my aim is to create the pwm on both sides, the grid side and the rotor side, with each two controlled voltage source. All this should be modelled on simulink. Unfortunately i cannot (...)
Does the overcurrent occur at a certain point in each mains waveform? When mains voltage amplitude is near zero (twice per cycle), is your amplitude high? Then that means your waveform is pouring current at the wrong point in the mains waveform. It could be a power factor issue.
In actual practice wouldn't you just set the maximum current and pwm the voltage to keep a constant current. A V/f operated inverter is voltage controlled, the current varies according to the load. Current limiting may be implemented as an auxilary function. It should be mentioned however that only few recent VFDs (...)
The control topology makes no sense. You can either operate the system with current or voltage controlled feedback. But what's the purpose of substracting voltage and a current proportional value?
"voltage controlled Pulse Width Oscillator" Found in this lengthy collection of circuits for the 555 timer IC. (Scroll halfway down.)
pwm is generated by an electromechanical or electronical timer, switching the input to the high voltage transformer supplying the magnetron.
do you mean like having a 3-phase controlled rectifier and you change the firing angle to acheive the variable DC voltage you want? well, at least i said something :)
YOu better review your Gate voltage levels for turn off and timing vs Threshold. Note detailed selection of RC+diode control of gate voltage. This following design uses fast turn Off and slow turn on. Dead time is critical, which is controlled in this
You can regulate either current or voltage at one time.
Since the intensity of a LED is controlled by current and not voltage, the best way to dim it is to use pwm and a variable duty cycle. You set the max current by the output voltage and a resistor to generate the current through the LED, or you can use a special switch mode driver that generates a specified current. The (...)
The 555 pwm circuit that Electro ns referenced is controlled by a floating mechanical pot and is not readily controlled by a voltage input as the OP wanted. Here is an IC that should allow you to control the motor speed by the control voltage using pwm. You will need to add a (...)
here's a few ideas - drop the 0.3R to 0.1R if you mount all active devices on a CPU cooler with low speed fan. - use a series pass transistor as pwm controlled charger to maintain a lower voltage drop on the regulators or use a stock SMPS to maintain a 2 V drop on the linear regulator. - use a lower
Hi all, I am making an H bridge for a supply voltage range of 12V to 24V and a max current of 4A. The motor speed will be controlled by a pwm signal (>10kHz) provided by a PIC microcontroller. I noticed that for driving the gate people use gate drivers (because the gate has some capacitance and it needing more than 5V to fully switch (...)
Hello friends, I want to make power supply which is controlled by PIC mcu (with filtrated pwm outputs for current and voltage limit) and with LCD for show voltage and current measurements. I tried to find some good schematics for this and didn't succeeded :-(. I need IDEA how to do this. So, some internet links, or (...)
You said the current sense signal would be compared to a reference signal. That reference signal itself would have to be controlled according to the lookup table for micro stepping. Essentially your micro controller would no longer be providing pwm directly to the motor. Instead you pwm could be filtered into an analog (...)
The section on the right is just a large voltage amplifier. As for the part on the left, I can't really tell without knowing specific component values.
Hi, Anyone who has experience with that how to get a pwm signal whose Puls should be controlled based one the I/P voltage ?5V Using simple OP-Amp ? Thanks in advance
If you are trying to control a normal CPU fan, designed to connect to a PC motherboard, then that circuit won't work. The fan is not voltage controlled, it is pwm (pulse-width modulated) controlled. You need to make a pwm controller - there are many examples if you search google, here is one that's (...)
Take a step back and ask what attribute of the solenoid you are trying to control. Current? voltage? Position? Flow? Get your mind right about feedback. There's plenty of options for power switches, drivers and so on. But these are only the nuts and bolts, and I don't see a plan.
voltage controlled oscillators based on the 555 series are well known. One way to do that with your MCU would be to generate a pwm output, then pass that through a low-pass D/A filter, say 10K and 10 uF (just a guess). Use that voltage output at the Control voltage pin (pin5) of the 555. Why would you (...)
Better working circuit based on same pwm function is achieved by comparing triangle wave against voltage set by potentiometer. Triangle wave is used because it has slope against time, so on time and off time is easily controlled. A capacitor is charged and discharged wi
Digital potentiometer in picture has value for max. current <2.5mA & max. voltage 5V I thought that might be a problem. Also, getting a pot with a low enough value could be difficult as well. I still think the constant-current source would work well; a cheap transistor and 2 resistors and the digital pot. Still, if y
hello friend thank you i came to know about a good pulse width modulator with your post. you have to use two pots one for varying duty cycle and other for varying frequency. you didnt told at what voltage you want to operate. i suppose it as 3V and you have to connect 2K ohm resistor plus 1k ohm potentiometer and 100 ohm resistor in series between
looks like voltage controlled pwm to me. PIC reading voltage value through ADC and feed it to pwm, so its duty cycle varies proportional to voltage.
How output of an inverter can be controlled? What is the need of voltage control of full bridge inverters? It all depend on your desinge of the inverter and the type of oscilator used,some of the ic's used as oscilators has an in buid pwm control by feeding in feed back loop to the pwm control pin,eg SG3524.352
In the first step convert 4-20mA to 1.0-to-5.0V using 250Ω resistor .. In the second step, apply this 1-5V control voltage to voltage controlled P(ulse) W(idth) M(odulator) = pwm .. Here are details of the voltage controlled pwm:
Hi, I have a question about the error amplifier in a voltage mode controlled buck converter. I designed a TYPE III erroramp with the correct transfer function to give me a stable loop in combination with the LC plant and the pwm modulator. According to the books, so to say. In simulation everything works fine, exept for one thing: the (...)
Hi everyone, I design a Boost circuit with specification: Input: 3.3v Output: 5v, 50mA After soft-start, the output voltage increases very high: around 18v. Then it decreases to 10v, but very slowly. How can I control the output voltage? Best Regard! Thanks
1. FISHER, NGO and KUO; ?A 500 KHz, 250 W DC-DC Converter with Multiple Outputs controlled by Phase SHifted pwm and Magnetic Amplifiers ? HFPC 1988 2. ANDREYCAK, W. ?Controlling Zero voltage Switched Power Supplies?; HFPC Proceedings, 1990 and any papers related to design of phase shifted zvs full-bridge dc-dc converter
Impossible without input voltage.
So i'm in the process of converting a voltage controlled device into a current controlled device which utilizes the PIC16C54C microcontroller. The original voltage controlled schematic involved using multiple ZVN3306FCT-ND MOSFET transistors which were controlled by the PIC. These MOSFETs (...)
i am fibished with ths job.. i did it using a voltage controlled oscilator integrated circuit called 8038. i amplified the output of the microcontroller using an octocoupler. i obtained the DC value of the pwm pulses using an R-C circuit.. then i fed this DC value to the 8038 integrated circuit. now by changing the duty cycle of the (...)
the pwm is a good idea, but if the contrast voltage is negative used a diode doubler circuit for negative voltage
Hey everyone.... Im working on a new one now and I just wanted to get some input.... Ive been thinking of building a "dummy" load for test. I am thinking of using a PIC16F676 to read and display voltage and current... I was thinking of using the pic to limit the current by using pwm and shunting a MOSFET through a limit resistor to ground. But I do
Hello, Can any body tell me what is the maximum allowable ripple voltage at the output of a DC-DC buck converter. Thanks Kasi
Hi to control the brighness you need to conrol current passing in the led. To do this you can either coontrol the current itself or to control the resistor through which the current is passing. To control current itself, you will use a voltage controlled current source where the voltage control signal is a low pass filtered version of (...)
The LM321 can work with the input voltage of 0V. What is the maximum voltage of your pwm I/P? I thiank this maybe not a safe salution.
if sinewave generator+power mosfet is pwm, regulator state can be removed to save energy and output voltage can be controlled by feedback output to pwm.
Feedback loop will regulate the o/p voltage and also stabilize the ckt. bimbla.