tylerjbrooks
Newbie level 3
I have been messing around with various topologies in an attempt to make a Sinewave dimmer (sometimes called a universal dimmer). I don't see many examples of these things on the web so I am a little in the dark. Has anybody made one before? Could you share your ideas?
Please see the attached schematic.
I started with a standard buck regulator inside a bridge rectifiter. I moved the load and capacitor outside the bridge rectifier so that the load would experience sinusoidal current and voltage. I left the inductor inside the bridge so that I could use the diode to counteract the inductive buck. Capacitor C2 and resistor R3 are there to act as a snubber to squelch some of the spikes.
This all spices out reasonably. However, it doesn't maintain a sinusoid as the dutycycle is reduced. Around 30% or lower dutycycle, the peak of the wave begins to collapse. To fix this, I plan on varying the dutycycle with the phase of the sine wave (shorter pulses near 0 and 180 degrees, longer pulses near 90 and 270 degrees).
I guess my question is: Am I on the right track here? Is there a better topology?
Please see the attached schematic.
I started with a standard buck regulator inside a bridge rectifiter. I moved the load and capacitor outside the bridge rectifier so that the load would experience sinusoidal current and voltage. I left the inductor inside the bridge so that I could use the diode to counteract the inductive buck. Capacitor C2 and resistor R3 are there to act as a snubber to squelch some of the spikes.
This all spices out reasonably. However, it doesn't maintain a sinusoid as the dutycycle is reduced. Around 30% or lower dutycycle, the peak of the wave begins to collapse. To fix this, I plan on varying the dutycycle with the phase of the sine wave (shorter pulses near 0 and 180 degrees, longer pulses near 90 and 270 degrees).
I guess my question is: Am I on the right track here? Is there a better topology?