Hi all,
Hopefully someone will be able to help me. I have just started messing with this stuff and I do not have much of a theoretical background, although I know the basics of resonant circuits and I am picking up the rest as I go.
I want to implement a basic wireless energy transfer system (loose resonant coupling) for eventual use in a rotating POV display. I started with the basic ZVS driver circuit (intended for use as a flyback driver), wound a few different coils and started experimenting. Here is my setup:
with this coil I was (from memory) getting an inductance of about .027mH, coupled with a 100nF cap for a resonant frequency of ~96KHz. The secondary here is matched.
I also tried winding a higher-Q primary, which you see here. The inductance of this coil is unknown but I was able to achieve coupling by tuning the coil using the ferrite rod that you see. This one yielded slightly higher efficiency, but...
With both of these setups I could not pull more than 60-100mA off the secondary, and certainly not enough power to blow up the LED (without current limiting), which is what I would have expected!
Tuning the tank capacitance for higher frequency (up into the MHz range) reduced the efficiency still further.
The driver is using 2n7000 MOSFETs which I know are pretty underrated, but they're not even getting hot at resonance. Current draw of the driver circuit is in the tens of mA range! Almost as though I am not injecting enough current into my primary circuit.
Now, as I said, I'm just starting out in this stuff, so please be gentle. Could someone possibly suggest where I may be going wrong in these experiments?
I'm not expecting great efficiency, but I have seen people light incandescent bulbs with a similar setup - yet I can't get enough power to blow a poxy LED.
Hopefully someone will be able to help me. I have just started messing with this stuff and I do not have much of a theoretical background, although I know the basics of resonant circuits and I am picking up the rest as I go.
I want to implement a basic wireless energy transfer system (loose resonant coupling) for eventual use in a rotating POV display. I started with the basic ZVS driver circuit (intended for use as a flyback driver), wound a few different coils and started experimenting. Here is my setup:
with this coil I was (from memory) getting an inductance of about .027mH, coupled with a 100nF cap for a resonant frequency of ~96KHz. The secondary here is matched.
I also tried winding a higher-Q primary, which you see here. The inductance of this coil is unknown but I was able to achieve coupling by tuning the coil using the ferrite rod that you see. This one yielded slightly higher efficiency, but...
With both of these setups I could not pull more than 60-100mA off the secondary, and certainly not enough power to blow up the LED (without current limiting), which is what I would have expected!
Tuning the tank capacitance for higher frequency (up into the MHz range) reduced the efficiency still further.
The driver is using 2n7000 MOSFETs which I know are pretty underrated, but they're not even getting hot at resonance. Current draw of the driver circuit is in the tens of mA range! Almost as though I am not injecting enough current into my primary circuit.
Now, as I said, I'm just starting out in this stuff, so please be gentle. Could someone possibly suggest where I may be going wrong in these experiments?
I'm not expecting great efficiency, but I have seen people light incandescent bulbs with a similar setup - yet I can't get enough power to blow a poxy LED.