What is Pwm: Definition and 76 Discussions

PWM rectifier is an AC to DC power converter, that is implemented using forced commutated power electronic semiconductor switches. Conventional PWM converters are used for wind turbines that have a permanent-magnet alternator.
Today, insulated gate bipolar transistors are typical switching devices. In contrast to diode bridge rectifiers, PWM rectifiers achieve bidirectional power flow. In frequency converters this property makes it possible to perform regenerative braking. PWM rectifiers are also used in distributed power generation applications, such as micro turbines, fuel cells and windmills.
The major advantage of using the pulse width modulation technique is the reduction of higher order harmonics. It also makes it possible to control the magnitude of the output voltage, and improve the power factor by forcing the switches to follow the input voltage waveform using a PLL loop.
Thus we can reduce the total harmonic distortion (THD).

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  1. R

    Does anyone make zero-flicker computer monitors?

    Are any of the low-flicker monitors completely flicker free, not just low enough flicker to meet some low-flicker certification. Ideally I’m looking for something completely flicker-free like the LG EVO OLED TVs but smaller. I do not know all the terminology but some things I’ve been told to...
  2. PhysicsTest

    PWM sweep from 0 - 100% duty cycle in LTSpice

    How do i simulate the PWM signal with duty from 0% to 100% in Ltspice. I can generate a pwm signal with single duty.
  3. Echo43

    Can Resonant Frequency Disassociate Water Molecules?

    I am experimenting with finding the resonant frequency of water in an attempt to disassociate the H2O bond without high voltage/current and using just tap water - no electrolytes, etc. I know how it works in classic electrolysis but that's not what I am attempting. Assume that there is a...
  4. N

    How to Implement 25us Delays in PIC16F84A PWM Code?

    Hello how are you :D I have some problems with my code, which is to control the speed of a DC motor by pwm with the pic16f84A. I already have the combinations and the diagram of the signals, but I still need to implement the part in bold. How would the delays be implemented so that they have...
  5. S

    Isolate solar charger PWM pulses

    After we got the solar array working, we made all lamps, laptop chargers, most kitchen appliances... run on 48vDC (so that we can have the inverter switched off unless we're running any 220v appliances). Then everyone in the house got a headache. We traced this down to being indoors at daytime...
  6. Z

    PWM signal generating circuit based on LM393

    This is a PWM signal generating circuit based on LM393. When I was running this LM393 circuit, I found that this circuit only consumes about 10 milliwatts of power at a voltage of 5V. Not only that, this circuit can work normally at 3.3V, 12V and 18V. But later I found that this circuit...
  7. maxwells_demon

    Papers on the Mathematical Basis for Using PWM for Sine-Wave Generation

    Need some sources on why PWM is widely used in inverters for DC - AC conversion applications, and their mathematical basis? Basically, I was wondering why inverters had to use PWM, instead of just getting a square wave of let's say a 50Hz frequency and just filtering out the odd order harmonics...
  8. A

    Signal Integrity of PWM Across Boards

    Hello, Looking for advice/thoughts on a PWM signal going across multiple PCBs. The signal would be relatively slow (1kHz) but I've really only ever dealt with PWM on a single board or cable. The premise of this effort would be to have a PWM control signal and be able to daisy chain multiple...
  9. kunalvanjare

    PWM for controlling liquid flow through a Solenoid Valve

    Hello guys, I am looking to control the flowrate of water through a Solenoid Valve in a continuous closed-loop process. I inquired about Proportional Flow Solenoid Valves and these are a little too expensive and only a handful of manufacturers are supplying those. But I looked online for some...
  10. Sveral

    PWM and it`s duration (picosecond pulse widths)

    Hello, I wanted to ask, if anyone knows of a realistic circuit, which could be capable of producing a PWM of 1 pico second on and 350 ps off. Thanks to everyone taking the time to answer in advance.
  11. Tesladude

    MOSFET not working with digital input gate signal, Help please

    Ok, so i have a picaxe microcontroller putting out a pwm signal to the gate of an irlb3034 "logic level" n-channel mosfet. The mosfet is for grounding on and off about 8v of 20 to 40 amps. When i take my circuit and jump 8v directly to the gate of my mosfet everything works perfectly...
  12. Archie Medes

    Analog zero-point synced AC PWM: is there a better way?

    Hi, Thinking of a circuit to control the AC power to a heating element. I wanted something fairly linear, and analog. I don't have anything against using a programmable controller, I just wanted to think of an analogue solution, seeing as I don't need to learn how to write a program. The...
  13. C

    Control Solenoïd Valve Proportionally w/166Hz PWM

    Hello everyone, I have to control a solenoïd valve proportionally using a 166Hz PWM signal. The resistance of the coil is 2,5-4 ohm. If i'd be using a pure DC signal I'd have around 8 amps of power. However this is an oscillating signal. Since a coil resists changes in current, the effective...
  14. rumborak

    Could PWM be applied to emulate resistance?

    This thought occurred to me when reading about class D amplifiers, which essentially "emulates" amplification by very quickly switching on and off. Could one use the same principle to eliminate for example heat losses during impedance matching? IIRC, in the perfect condition of matched...
  15. T

    Simplest way to build a light dimmer using PWM

    I need to build a light dimmer using the PWM on the microcontroller to dim an incandescent 60W bulb. What would be the simplest way to do it ?, any suggestions ?, would a optocoupler and triac suffice ?
  16. SSGD

    Microcontroller Pulse Width Modulation to Analog DC Voltage

    What are some effective ways to convert a Pulse Width Modulation from a Microcontroller to a DC Voltage as a function of Pulse Width? 1. Use a low pass filter to remove the unwanted harmonics and leave only the 0th term of the Fourier Series. What produces a better DC Voltage an Active or a...
  17. I

    A Can PWM sine pulses be generated without a lookup table?

    I need an algorithm for generating a pwm (pulse width modulation) sine, but with an important constraint: it is not allowed to use a lookup table. The pwm encoded sine pulse sequence must come directly from the algorithm itself. All attempts to find it were in vain. Can you help me? Thank you in...
  18. D

    Question about PWM inverter output

    So, this is what I know so far, please correct me if I'm wrong. The amplitude of the output of a PWM inverter depends on how long the sinusoidal modulating signal is greater than the carrier. If you subtract the output (scaled down) from a reference signal in order to get some error and use...
  19. Shuvam Agarwal

    How to get a pwm output for a 35 V, 0.35 A dc input signal?

    I am doing a project where I need to control brightness of a led light. according to presence. the brightness can be controlled using pwm but I cannot find a way to do that for high voltage input signals.
  20. J

    24VDC 0,570 Amp pump controller

    Hi,So let's start with this, I don't have a lot of electronics circuits background and not really an idea on how to build an electronic circuit. Ok, now the problem, at my job I am in need of controlling a 24VDC 0,570 Amp pump with a pot, preferably one with a "preset" in it so that the values...
  21. J

    I built a 3 stage PWM solar charger using an arduino

    I am an electrical engineering student. I have been on summer break for a few weeks now and I had time to work on my project. This is not a school project but something I had wanted to complete for a while. I haven’t decided what I am going to do with it yet. I just built it for the fun of it...
  22. W

    How do pull up/pull down resistors affect PWM signals in motor control?

    Hi all, I am an electrical engineer and feel I should know this (embarrassing!), but I for the life of me still can't quite get this concept. I understand conceptually the idea behind a pull up or a pull down, in that we want the IC to read a high state, by defaultm in the case of a pull up...
  23. H

    Control design for PWM converter

    Hi Everyone, here is Hubert again. Here attached is my design and the problems I am facing. Can anyone be of help? Thanks in advance. Best regards Urbain
  24. B

    Troubleshooting a PWM Circuit Design

    I need to design a pwm circuit, i using the circuit from internet that i attached it.. freq is 20khz which is my requirement and 15v to power up the tl494.. there is no response when i connect potentiometer to it... waveform is attach can anyone give me advice?
  25. H

    PID controller for current control by adjusting the PWM

    Hi, I'm a starter here! I am trying to build a buck converter without the use of any IC. I want to drive a single LED. Here are some calculated data: Vin =5V, Vout =3.225V, Duty circle = 0.651, L=6.8micro Henri, Switching frequency = 1.4Mhz, Desired current is 1A, I also assume ripple current...
  26. C

    Can somebody please explain and walk me though this motor drive circuit?

    The Drive terminals are connected to a PWM signal generated by an arduino micro controller. The purpose of this circuit is to isolate the arduino from the motors to avoid too much current being drawn. What I understand so far: The motor will only turn when the diode is reverse biased. When it...
  27. J

    Help selecting the proper size PWM for a motor

    I'm building a machine using a 3-12VDC gear motor, 1.5A draw no load, stall at 25A. Would a PWM rated at 6-90V 15A 1000W be an appropriate controller? These two items: https://www.amazon.com/gp/product/B00HTZSK5Q/?tag=pfamazon01-20 https://www.amazon.com/gp/product/B005IR1NBA/?tag=pfamazon01-20
  28. S

    PWM Controller period and duty cycle questions

    I've carried out some testing on a PWM controller using a 555 timer IC (see attached for circuit diagram) and I am having a little trouble understanding the results. When the POT resistance is increased the duty cycle decreases. As I understand it, when the resistance is increased the voltage...
  29. P

    Understanding PWM Inverter Input & Output

    Hi, could someone confirm whether I am right in thinking that for a PWM inverter, the input sine voltage is converted to DC using a bridge rectifier? Does this DC voltage then have a value which is the same as the PEAK value of the sine input? Is the DC voltage then 'chopped' using IGBT's to...
  30. P

    PWM Inverter Drive explanation please

    Hi, I understand that the PWM inverter drive system first uses a diode bridge rectifier in order to convert the AC incoming into DC before using an inverter to convert this DC into PWM for use on the induction motor. Could someone please explain in simple terms how the PWM inverter section...
  31. F

    Transmission of PWM signal not working.

    Hey guys, So I'm working on a project currently being built off of a cheap commercial Quad-copter (Syma X1) as it's base platform. Just as a little background I am trying to make it so that it is not controlled by a remote (that is pushing knobs and levers up and down to control it) but by EMG...
  32. EagleOnePro

    Can I Use PWM to Control My Electromagnet with a MOSFET and 12V Battery?

    Hi, I need help with my electro magnet pulse with modulation PWM. I have a Velleman® IR Light Barrier Kit from Radio Shack and this kit is ment to turn on and off a 9V buzzer. But instead of soldering in the buzzer I tried to hook it up to a MOSFET transistor NTE2984 so that I could use it with...
  33. M

    Is PWM for control of Peltier Element logical?

    I'm making a circuit to control the temperature of a peltier element, and I'm trying to figure out the cheapest way that will actually work over the long term, and not burn out my components fast. At first I wanted to just use standard power regulation to control the power to the element and...
  34. P

    Changing the duty cycle of a PWM signal

    I'm trying to control the speed of a computer fan using the radio input from an RC transmitter/ reciever. The PWM output of the reciever is 1ms to 2ms high and 20ms low, so 10%-20% duty cycle. The computer fan requires a 30% to 100% duty cycle, at 25khz (about a 40uS pulse) I was thinking of...
  35. W

    Looking for Analog to PWM signal -

    Hello All: This may be a repeat post - I looked at my history and did not see it. I am looking for a product ( finished/qualified) that takes a standard Analog signal ( 0-10V and/or 4-20mA) and converts to a PWM signal with fixed but settable; Frequency of ~ 100 to 5000hZ - possibly with a...
  36. V

    Why Use Both Voltage and Phase Control with PWM for AC Motor Speed Regulation?

    I want to controll ac motor using pwm.sir told me for that you required volage controller and phase controller.if voltage is controlled by pwm so why i want to use this phase and voltage controller?
  37. Artlav

    PWM controlled fan responds unexpectedly

    Hello. I'm trying to control the speed of a fan (12V cpu cooler) with PWM (555 + MOSFET). Should be quite straightforward, but i noticed that the speed of the fan does not seem to always change in the same way the duty cycle does. With an optical RPM meter I'm seeing that the lowest RPM...
  38. N

    Peltier Project: Increasing Performance w/ 50% PWM & Alternating Circuits

    Peltier Project: 50% PWM --> alternate circuit switching for increased performance? Hi all, I have a project where I am making a drink cooler device using four peltier devices which can draw up to 30amps or 24 volts each. we are considering battery power (pretty ridiculous but anyway..) and...
  39. R

    Debugging C Code of Heating Machine - PWM & Actual Current

    Hi, I am debugging a C code of a heating machine. I am so confused about real time current and programming control over all the parameters of the machine. The code was written by some one though, i understand it well until now. Problem is that the previous code works according to...
  40. G

    Can You Run PWM Fan Without PWM Input?

    Excuse my lack of knowledge on PWM and fans, but can a fan configured with 4 wires (power, ground, tach. signal, and PWM input) be run off of a DC power supply without using the PWM to control its speed? As in, not using the PWM lead and just hooking up power/ground and controlling fan speed...
  41. F

    DMA Scope: Affordable PC Oscilloscope for PWM Waveforms

    Hi, i need an oscilloscope but i don't have money to buy one, so i was thinking about some way to use the PC to emulate an osciloscope. I saw on internet people using the sound board, but they say that's a lot of interference... So i found a PC Oscilloscope and i wanted to know if it works. I...
  42. N

    PWM, Limit switches, and TX's / RX's

    Hey everyone. I am a total noob to electronics, so I would really appreciate your help on my first engineering project! I am building an RC Excavator and need help with the circuits for the linear actuators I plan to build. I have 3 DC motors on the way with a voltage range from 6-12V. I have...
  43. T

    Engineering Determining motor speed from PWM waveform

    As part of a lab report I have to determine the speed of a motor from the PWM waveform. The motor in question is a lego motor, of type at disassembled at http://www.philohome.com/motors/motor.htm. It has three coils on the rotor and a 4 pole permanent magnet stator. This is the waveform I...
  44. E

    How Can I Generate a 2kHz PWM Control with PIC16F84?

    hello friends, how can i generate a PWM control 2 kHz with PIC16F84
  45. S

    Design PWM to cope with supercapacitor and battery(help)

    I need to design an electric circuit which require PWM to let the battery and supercapacitor take turn to supply current to the loads. stage1: battery charge up supercap and supply current to the load stage2: supercap voltage increase to a certain level, battery current is cut, supercap...
  46. E

    Difference between Pulse Wave and PWM ?

    Hi! I have been getting really confused about this one thing. Can someone please clear my confusion ? Is there a difference between Pulse Wave and Pulse Width Modulation? If yes, what is it ? If no, can one be used in place of the other ? :smile: Thanx !
  47. D

    Can an Arduino and PWM circuit be used to create an arc generator and speaker?

    Hello everyone. My first post so bear with me. I'm planning on buliding an arcgenerator (and possibly an arc speaker later on if this works) with my arduino and a coil. I'm relatively to electrical engineering, so there are a few things I need some help with. If I've understood things...
  48. L

    Pulse Width Modulation & Servo Motors Explained

    Hi everyone, I am really trying to get the concept of Servo Motors and am sort of stuck on something, particularly how the motor gets its Pulse Width Modulation. I understand the 0 to 5V with a period of about 20ms and different pulse widths generate different angular positions. What I am...
  49. L

    PWM and IGBT for 200V bulb dimmer

    Greetings! This is my first thread. I am creating a 200V bulb dimmer using PWM and IGBT. Currently, this is how I connect the components: The output of the PWM goes into the gate of IGBT. The bulb connects in series with the 220V supply and the collector of IGBT. The emitter of IGBT is...
  50. S

    PWM Drive to H-Bridge with IR2113

    I am using 4 MOSFETs in an H-bridge. The H-bridge is controlled with two MOSFET drivers (specially IR2113). I aim to drive the H-bridge via PWM which is carrying a 50Hz sine wave. Note that, the load is not a motor. Instead, the H-bridge is being used as a inverter. My question is, does the...