One of the interesting things about living here in the DR is that almost everybody has an inverter because the power is only on half the time or less. This has created a cottage industry phenomenon, A sort of generic inverter design that everybody and their cousin (or uncle) builds to sell.
Two main designs, one based on the trace DR Series, the other homegrown, with many variants. The boards are modular (you could in most cases put one of many control boards into your inverter as a replacement). Most of the control boards use a matching MOSFET (transistor) board. Separate ac input (TRIAC based) modulating charge controllers are also common, although most control boards include a charge controller circuit (for the charger function of the inverter). The inverters are of the inverter / charger variety, and commonly range from 12v-24v and from 1 to 6 KVA. The control boards range from 40 - 60 US$, and then you add the mosfets and the transformer, relay, etc.
All parameters are typicaly adjustable, and the boards are made without pesky surface mount parts. Some of the boards are Microprocessor controlled, some are not. One in particular uses an 8 pin PIC, and although the code is proprietary, it can only have (up to) 6 control pins, how hard can it be to reverse engineer? (with the schematic!) could be very interesting for folks who would like to build a DIY unit with monitoring capability, etc. (open source inverters, anyone??)
A 3.5 KVA inverter - charger can be built for about $400 US, smaller ones (1 - 1.5kva) for around $160ish. Of course, the high frequency designs from china are much cheaper, but these are DIYable repairable, modified sine (modified square) inverter - chargers with transfer switching and current / voltage adjustable chargers, adjustable ac / dc cut in cut out, etc.
One thing I am working on is a PWM wave shaping stage that might be able to be integrated into these designs, to make a full sine unit.
Anybody aside from myself me tantalized by the possibilities?
