The choice of pump type, size, and capacity depends on the application and its requirements. In principle, submersible pumps are used in wells deeper than 7 meters and surface are used for shallow wells.
Regardless of that, DC motors are widely applied in small applications with capacity not exceeding 3 kW, mainly applicable for small water demand such as gardening, landscaping, small volume livestock watering, etc. DC pumps are more efficient and more practical as they do not require an additional component to convert current to Ac for instance. This reduces costs and avoids additional efficiency drops.
Ac pumps are used for larger applications with capacities exceeding 3 kW, requiring an inverter to change the current that the solar panels produce (DC) to a current that is suitable for the pump (AC).
Latest 3-phase pumps use a variable frequency AC motor and a three-phase AC pump controller that enables them to be powered directly by DC power produced by the solar modules.