A Constant Current and Constant Voltage Charging Circuit through MPPT Method and Its Stability Analysis

Abstract

In this paper, a constant current and constant voltage charging circuit through MPPT method, and its stability analysis is proposed. The input part is a solar cell array, the converter uses a super buck circuit, and the output is a battery pack, which constitutes an unregulated primary power bus system. Aiming at the dynamic characteristics of the solar cell output, small-signal modeling of the solar array is carried out. To convert the super buck into a more suitable output constant current source model and accomplish the design of the constant current and constant voltage circuit for the closed-loop control, the average space state method is used for modeling and the proposed circuit’s switching stability can be verified at the same time. The experimental results show that the system can accurately track the maximum power point of the solar cell array in MPPT mode, charge the battery pack with constant current or constant voltage control, and maximize energy utilization of SAR solar power system.