The biggest difference is the difference in charging speed, which respectively represent the fastest charging of 7 degrees, 11 degrees, and 22 degrees per hour.
Different backward compatibility, 7kW can be backward compatible with 3.5kW, 11kW can be downward compatible with single-phase 3.5kW, 22kW can be downward compatible with 16kW, 11kW, single-phase 7kW, 3.5kW.
The purchase conditions depend on the power of the meter you apply for. If your community can install 380V, it is recommended that you choose "Energy Efficiency T22 Smart Fast Charging Pile" with 22kW DC output, 10-fold safety protection, fast charging, and high safety.