Abstract : This paper introduces a method for achieving CVT (Constant Voltage Tracking) type MPPT (Maximum Power Point Tracking) control by using a general-purpose frequency converter to drive a photovoltaic water pump. Practice has proven that the system can achieve good control results. Keywords : Inverter, Solar Photovoltaic Array, CVT, MPPT, Photovoltaic Water Pump 1. Introduction The basic principle of a "photovoltaic water pump system," also known as a "solar photovoltaic water pump system," is to directly convert solar energy into electrical energy using semiconductor solar cells, which then drives various motors to power a water pump that draws water from deep wells, rivers, lakes, ponds, etc. In some small-to-medium power photovoltaic water pump systems, DC brushless motors are often used as the drive motor, while in some larger power systems, AC asynchronous motors are also used. In cases where AC asynchronous motors are used as the drive motor, a dedicated photovoltaic water pump inverter is typically employed. However, using a dedicated photovoltaic water pump inverter presents several limitations: its application is relatively limited, it is not a standardized product, manufacturing processes are not guaranteed, and maintenance is inconvenient. These limitations hinder the widespread application of photovoltaic water pumps. Therefore, we designed a photovoltaic water pump control system that uses a general-purpose inverter instead of a dedicated photovoltaic water pump inverter. 2. Composition of the Photovoltaic Water Pump System A photovoltaic (PV) water pump system typically consists of a solar photovoltaic array (hereinafter referred to as the PV array), a water pump frequency converter, and a pump, as shown in Figure 1. Unlike common water pump systems powered by AC mains, the PV water pump system uses the DC power output from the solar photovoltaic array as its power source. The output of the solar photovoltaic array is a strongly nonlinear DC power supply, greatly affected by meteorological conditions such as sunlight and ambient temperature. To ensure the PV water pump system can reach its maximum output power potential under any sunlight and ambient temperature conditions, a controller is needed to achieve a harmonious, efficient, and stable working state between the power supply and the load. The frequency converter in Figure 1 is responsible for this function, primarily implementing MPPT (Maximum Power Point Tracking), inversion, and some protection functions. The pump is the system's actuator, including the drive motor and the water pump itself. The system load can be adjusted by regulating the pump's speed. [b][align=center]For more details, please click: Application of General-Purpose Frequency Converters in Photovoltaic Water Pump Systems[/align][/b]