The SOLiC works by varying the proportion of on-time to off-time using 'very' fast power switching, mathematically creating a continuously moving average output power over 5 seconds approx. The resulting RMS voltage fed to the immersion element varies from zero to full mains depending on the instantaneous decision made by the microprocessor.
EMC compliance is achieved by judicious use of 'snubber' networks and 'capacitor decoupling', along with carefully considered circuit board component positioning and track layout. The sealed metal enclosure traps any stray radio signals inside. The power requirement to run the unit takes advantage of noisy mains and harmonics. A switched capacitor filter arrangement is used to keep the power factor close to 1.0.
Harmonic compliance is achieved by taking advantage of deliberately introduced prime number switching points (spread spectrum rotating vectors), averaged over every 200ms or 10 cycles, as specified by the standard. Harmonics are mathematically cancelled out resulting in low level high frequency noise which is then filtered out.
The low voltage directive is met, again, by carefully considered physical planning, spacing components and tracks of high potential difference to ensure reliability and safety even under abusive conditions. Thermal control and electrical safety are also controlled by careful choice of material properties such as the anodised aluminium enclosure to conduct heat, resist moisture corrosion (condensation), physical impact and vermin or insect ingression. )
In mode 2, The current direction flow to (or from) the house is measured in a similar way to how a standard electrical meter does it. The instantaneous voltage, current and power factors are measured and calculated. The microprocessor mathematically integrates the readings every few seconds to determine which way the current is flowing. It then uses a proprietary control algorithm to change the current level needed to to offer the Immersion circuit to hold the energy export at zero.
In all the whole process works exactly like an industry standard power factor correcting system, that uses load resistors as a power dump instead of inductive or capacitative control.
And of course as you can see it works!
