[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[TCML] 4 Quadrant AC Chopper / Solid State Variac

Attached is a present (2006) 4 quadrant AC chopper to be used for
light dimmers for stage/theatrical applications.  The advantage of
this particular circuit topology is continuous current conduction mode
operation (no dead time) and is specifically designed to tolerate and
operate with reactive current components. As shown the prototypical
circuit capable of supplying a 300W load, but scaling appears
straightforward.  The logic within the PAL / FPGA could be
implemented with 5 or 6 discrete CMOS / TTL logic chips, although
a PLD/PAL/small FPGA makes a lot of sense if one has access to the
supporting development hardware/software.  This glue logic might even be
possible using an Arduino with DIO, although level translation would
be required on either side of the controller.


With independent duty cycle and current feedback control; a true solid
state variac + ballast replacement subsystem seems possible. If wide input
voltage range logic power supplies are used for housekeeping power
(85-280V input), a 120/240V system could be relatively easily built in
a quite small footprint.

Dave Sharpe, TCBOR/HEAS
Chesterfield, VA USA

Sharpe's Axiom of Murphy's Law
"Physics trumps opinion!"
Tesla mailing list