# Mixing two or more AC sources to handle overload

Can I mix two or more AC sources to handle overload and maintain a stable voltage of 230V AC?

For example if power from solar panel cannot handle a heavy load can I mix power from different source say a battery (after inverting) or main grid.

Bear in mind that the other source should not provide half the power but only complement that the solar panel cannot provide to handle the load.

If it can be done, how?

Mixing AC sources as you are imagining is an absolute nightmare; you need to control the amplitude and phase angle exactly. It is sort of possible using a multi-primary ferro-resonant transformer, but with extreme losses (and cost), so I imagine that isn't something you would be interested in.

Your best solution would simply be to operate your load off of a single DC battery Link, driving an inverter. Size a main's supply to be just lower than your solar supply voltage, and parallel them to the battery charging circuit with series diodes in each supply line. When the solar panel cannot deliver the required voltage, the mains supply will silently switch in.

You can control an active circuit with a PIC or Arduino and some MOSFETS if you want to actively control how much power is delivered by each source by PWM'ing the sources to the DC Link.

• I really want mixing to happen.... So is this possible....first ill convert the Ac powers to DC, mix thoses DC currents.. Then convert it back to Ac...Will it work? Will it be very lossy? and thanks for helping.. May 15, 2015 at 7:38

The simplest way to do this is first to make sure that your inverter can handle the power you need. I presume you already have a suitable battery for your PV system. Then, simply add another battery on the DC side of the inverter to ensure that enough current is supplied for your needs. The extra battery can be topped up using a separate charger and also protected with a diode.

Mixing AC supplies is not straightforward.

• I really want mixing to happen.... So is this possible....first ill convert the Ac powers to DC, mix thoses DC currents.. Then convert it back to Ac...Will it work? Will it be very lossy? and thanks for helping.. May 15, 2015 at 7:40