The solar power system includes PV grid-connected power systemand PV off-grid power system.

1. PV Grid-Connected Power System
PV grid-connected power system includes PV modules, grid-connectedinverter, meter and power switchboard. The PV modules convert thesolar energy to DC power, then the grid-connected inverter convertthe DC power to sine wave AC power which has the same frequency andphase with the grid voltage. The AC power feed in the grid partlyand the other power supply the local loads.

2. PV Off-Grid Power System
PV off-grid power system includes PV modules, controller, batteriesand off-grid inverter. The PV modules convert the solar energy toDC power, then the controller store the electricity in thebatteries. The DC loads can use the electricity directly. Theoff-grid inverter can change the DC power to AC power and supplythe AC loads.