Lauren Said:

Do **pv** **inverters** produce ac voltage?

We Answered:

PV inverters create voltage and current, yes.

However, the above author is mistaken in that you cannot have current without a voltage.

You can definitely have current without voltage. A superconductor is one example of this. By definition, a superconductor cannot have a voltage gradient across any two points in it, otherwise there would be resistance to currents.

Also, if you are not working in a high-power industry, wires can be very well approximated as being able to carry currents without having a voltage across them (although this is not strictly true)

Marlene Said:

Active **Power** P and reactive **Power** **Q**. What are their signs are source and loads?

We Answered:

Power inputs (contributions if you like) to the grid simply add up arithmetically as do the the various loads in terms of the power they consume. The grid itself consumes a small percentage all the power it transmits due to the resistance of its conductors and transformer windings etc.

One of the main tasks of a grid control centre is to balance power input and consumption in order to maintain the system frequency.

Jimmie Said:

How do I calculate the value of inductor and capacitor in DC-DC converter connected to DC-AC **inverter**?

We Answered:

Use the equation E = L (DI/DT). It is dependant on the frequency, the voltage and the inductance value. To insure continuous operation, the switch must turn on before the current goes to zero in each cycle.