Mosaic
Well-Known Member
I was looking at a 5A ,12VDC electronic transformer for a track light and it made me wonder about creating a variable voltage & current linear power supply by using the higher frequency approach to improve ripple numbers and remove low voltage linear regulation heating.
Since I am looking to use 'regular' iron core 60Hz rated transformers at a higher frequency, I guess I'll have to evaluate the balance between increased eddy current losses vs regulation and other efficiency gains. Working between 60Hz and 480Hz (64x eddy currents) is the goal.
The premise is this...
1) Create a variable higher frequency A.C. with a modified sine wave oscillator from rectified A.C. mains.
2) Use voltage & current control feed back opto or hall effect coupled from the low voltage side of the transformer to influence the amplitude of the primary voltage rise by throttling the oscillator frequency. Higher frequency = lower voltage peaks for a given winding inductance. Thus regulation is achieved.
3) This implies that while iron core losses increase at higher frq., this could be offset by the lower power (voltage or current) demand on the secondary side.
4) Low voltage bridge rectification and capacitor ripple handling will benefit from the higher freq. operation.
5) Use a hall effect current sensor to provide isolated feedback to the A.C. oscillator for current limiting. Optoisolator driven by a voltage reference for voltage regulation.
Is this worth a try?
Since I am looking to use 'regular' iron core 60Hz rated transformers at a higher frequency, I guess I'll have to evaluate the balance between increased eddy current losses vs regulation and other efficiency gains. Working between 60Hz and 480Hz (64x eddy currents) is the goal.
The premise is this...
1) Create a variable higher frequency A.C. with a modified sine wave oscillator from rectified A.C. mains.
2) Use voltage & current control feed back opto or hall effect coupled from the low voltage side of the transformer to influence the amplitude of the primary voltage rise by throttling the oscillator frequency. Higher frequency = lower voltage peaks for a given winding inductance. Thus regulation is achieved.
3) This implies that while iron core losses increase at higher frq., this could be offset by the lower power (voltage or current) demand on the secondary side.
4) Low voltage bridge rectification and capacitor ripple handling will benefit from the higher freq. operation.
5) Use a hall effect current sensor to provide isolated feedback to the A.C. oscillator for current limiting. Optoisolator driven by a voltage reference for voltage regulation.
Is this worth a try?