To overcome the unstable photovoltaic input and high randomness in the conventional three-stage battery charging method, this paper proposes a charging control strategy based on a combination of maximum power point tracking (MPPT), and an enhanced four-stage charging algorithm for a photovoltaic power generation energy storage system. This control algorithm ensures that the charging process is not affected by fluctuations in the photovoltaic power. The discharge bus waveform, push–pull discharge load switching waveform, push–pull circuit efficiency, and voltage and current regulation accuracies of the system were investigated. The experimental results show that the charging process is consistent with the designed four-stage charging control algorithm, the voltage and current regulation accuracies satisfy the charging requirements, the busbar remained stable during the battery charging and discharging switch, and the battery balancing effect was good.

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