Pulse Width Modulation and frequency, power electronics

[unkn0wn]

Pulse Width Modulation

Does Pulse Width Modulation change the frequency?

Is Pulse Width Modulation a type of Phase Modulation or Frequency Modulation or is it something else?

Is there any concept of Frequency Modulation in POWER Electronics??!

 

[Awarapunshee]

Re: Pulse Width Modulation

Pulse Width time Plus Space Width time equal to Time period. In Pulse Width Modulation the width of pulse is changed not the time period ( if pulse width is increased the space width decrease and the total time period remains the same)

 

[s_cihan_tek]

Re: Pulse Width Modulation

Hi,

PWM signals are generated by keeping the frequency (and hence the period) constant and varying the on time of the signal. They're neither a type of Phase modulation, nor a type of frequency modulation.

Frequency modulation and Phase modulation convey information over a carrier wave by varying its frequency and phase, respectively. On the other hand, in PWM, this information is conveyed by changing the on time of a constant frequency signal.

Regards

 

[ferdinand_leo]

Re: Pulse Width Modulation

Does Pulse Width Modulation change the frequency?

Is Pulse Width Modulation a type of Phase Modulation or Frequency Modulation or is it something else?

Is there any concept of Frequency Modulation in POWER Electronics??!

PWM is simply varying the Duty Cycle(DC) or On Time(Ton) of an square wave signal. Ton is frequency dependent, while DC is not...
Frequency is determined by the resonant components like capacitors and inductors.
DC is controlled by the feedback circuit.

In power electronics, there is the so-called Quasi-Resonance (QR) which is closed to FM but not actually the same. The frequency varies as per load and supply conditions to minimize losses.