Residential inverter usually refers to single-phase inverter and 3-phase inverter deployed in residential system. The power level of single-phase inverter is usually less than 10KW and 10KW to 50KW for 3-phase inverter. The system architecture of 3-phase residential inverter is very similar to that of string inverter discussed before.

The biggest difference is that residential inverter has much smaller number of independent MPPT inputs, and the number of PV strings per MPPT can be 1 or 2 depending on the power level. For example, a 50KW 3-phase residential inverter has 4 MPPT inputs and total 5 to 8 PV string inputs. This is much simpler for single-phase inverter. For example, a 10KW single-phase residential inverter has 3 MPPT inputs and total 3 PV string inputs. Figure 2-4 shows the typical single-phase residential inverter block diagram with hall-effect current sensors.

Considering the inverter power level and the target application scenarios, residential inverter does not have strict high accuracy requirement in string current sampling and MPPT boost current sampling, compared with string inverter. Because residential system is usually independent from each other and the deployment scale is minimal, this is not a big deal even low current sampling accuracy can cause some power generation output losses. While for phase current sampling, residential inverter has the same high accuracy requirement and reasons as those of string inverter.

Figure 2-4 Single-phase Residential Inverter Block Diagram with Hall-effect Current Sensors