Abstract : To address the power loss and poor adaptability issues in the maximum power point (MPPT) control of constant voltage tracking photovoltaic (PV) systems, an adaptive voltage change rate MPPT control method is proposed. This method detects the gradient change of the PV system's voltage-output power curve, derives the inverter voltage change using the least squares method, and uses a constant voltage PI controller to control the inverter's output frequency. The effectiveness of this control method is verified through simulation experiments on a PV water pump system. The results show that: ① the actual power generation of the system reaches more than 99% of the theoretical maximum power generation; ② it has fast start-up performance, with a start-up time of only 8 seconds to rated output; ③ it has good dynamic performance, and can quickly stabilize the output when the solar irradiance changes rapidly, avoiding system collapse. This method can be applied to various PV systems. Keywords : solar power generation; maximum power point tracking control method; inverter; constant voltage PI control; least squares method 1 Introduction In recent years, with the rapid development of China's economy and the sharp increase in electricity consumption, the power shortage situation is difficult to solve in the short term; moreover, with the depletion of non-renewable resources such as oil and coal, energy issues have become a focus of attention from many parties. Because solar energy is an inexhaustible, clean, and pollution-free energy source, its development and utilization have attracted the attention of governments at all levels. Many enterprises and research institutions have joined the ranks of developing and utilizing solar energy, and solar energy application products are emerging in an endless stream. This article introduces an unattended photovoltaic water pump system. This system is mainly designed for areas without power grids and can be used for agricultural irrigation, drinking water for livestock in pastures, and household water supply. The system can operate automatically when there is sunlight (including sunny and cloudy days). During the power conversion process, the frequency converter adopts a maximum power point tracking (MPPT) control method with an adaptive algorithm to maximize the power generation of the solar cells under the same light conditions, thus making the most of the relatively expensive solar cells. [b][align=center]For more details, please click: Maximum Power Point Tracking Control Method for Solar Power Generation Frequency Converter Drive System[/align][/b]