Constant pressure water supply is a water supply method for water conservancy systems. It is used to provide clean water resources in remote areas where power facilities are scarce; the controller can convert the direct current of the photovoltaic array into alternating current and drive various water pumps. It supports input and AC grid input, and can realize automatic switching function without manual intervention. It has a water level control logic function to avoid dry and water-free operation and adds a full water level protection function