There are some basic design criterias of solar inverters, such as:
voltage rating,battery capability,efficiency,output AC power quality,etc.

Voltage Rating—the most commonly used AC voltages are 120V or 220V for single phase and 208V/380V for three phases while 480V is also typical for three-phase industrial purposes.

Capacity/power rating—this number varies in a range from 200W (panel integrated modules) to several hundred of kilo-watts. The cost of solar inverters is calculated in dollar/W.

Battery capability—the addition of battery packs to the inverter DC side will serve as an energy buffer to smooth the possible voltage change and store the surplus energy that is not taken by loads. A favourable feature of battery capability is the continuation of supplying power when it is dark.

Efficiency—every solar inverter has its requirement on efficiency (output power divided by input power) and for example, a typical efficiency for a several kilowatt system is up to 95 per cent. Based on the fact that solar arrays have relatively low energy conversion efficiency, roughly 15 per cent or so, high efficiency of inverter is very important to have maximum output power with minimum area of solar panels.

Output power quality—the AC output waveform is not ideally sinusoidal and usually contains a wide range of high frequency harmonics caused by pulse width modulation (PWM). A good design of solar inverter is expected to output nearly sinusoidal waveforms and reduce the undesirable low frequency components going to grids.